WO2022241881A1 - Catalyst for dehydrogenation of alkanes into olefins and preparation thereof, and dehydrogenation method - Google Patents

Catalyst for dehydrogenation of alkanes into olefins and preparation thereof, and dehydrogenation method Download PDF

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WO2022241881A1
WO2022241881A1 PCT/CN2021/099761 CN2021099761W WO2022241881A1 WO 2022241881 A1 WO2022241881 A1 WO 2022241881A1 CN 2021099761 W CN2021099761 W CN 2021099761W WO 2022241881 A1 WO2022241881 A1 WO 2022241881A1
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catalyst
dehydrogenation
source
preparation
olefins
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French (fr)
Chinese (zh)
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周永华
林百宁
徐凡
刘雨薇
仇普文
王华伟
王雷
王宁
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中南大学
天津大沽化工股份有限公司
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J27/00—Catalysts comprising the elements or compounds of halogens, sulfur, selenium, tellurium, phosphorus or nitrogen; Catalysts comprising carbon compounds
    • B01J27/24—Nitrogen compounds
    • B01J35/615—
    • B01J35/647—
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J37/00—Processes, in general, for preparing catalysts; Processes, in general, for activation of catalysts
    • B01J37/08—Heat treatment
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C5/00—Preparation of hydrocarbons from hydrocarbons containing the same number of carbon atoms
    • C07C5/32—Preparation of hydrocarbons from hydrocarbons containing the same number of carbon atoms by dehydrogenation with formation of free hydrogen
    • C07C5/327—Formation of non-aromatic carbon-to-carbon double bonds only
    • C07C5/333—Catalytic processes
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C2527/00—Catalysts comprising the elements or compounds of halogens, sulfur, selenium, tellurium, phosphorus or nitrogen; Catalysts comprising carbon compounds
    • C07C2527/24—Nitrogen compounds
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P20/00—Technologies relating to chemical industry
    • Y02P20/50—Improvements relating to the production of bulk chemicals
    • Y02P20/52—Improvements relating to the production of bulk chemicals using catalysts, e.g. selective catalysts

Definitions

  • the invention belongs to the field of chemical synthesis, and in particular relates to a catalyst for preparing alkenes by dehydrogenating alkanes and a dehydrogenation method.
  • Olefins are important chemical raw materials.
  • styrene as a derivative of aromatic hydrocarbons, is an important monomer raw material for the production of high polymers in the chemical industry, and is widely used in fields closely related to people's daily life. It is estimated that the annual industrial output value related to styrene can reach 60 billion US dollars. In the past 20 years, with the continuous development of the global styrene downstream product market, the demand for styrene has increased year by year.
  • Lummus/Monsanto/UOP that uses potassium-containing iron oxide or zinc oxide as a catalyst to catalyze the direct dehydrogenation of ethylbenzene to produce styrene at a high temperature of 600-650°C and under the protection of excess water vapor (water/hydrocarbon ratio 7-15)
  • the process is currently the most widely used styrene production technology in the world. This technology research has a history of more than 70 years, and the corresponding research results have also been widely recognized. More than 90% of the total production. However, the large consumption of water vapor makes the whole production process consume a lot of energy.
  • the catalyst reported in patent CN105749934A can be used at a relatively low water/hydrocarbon (1.2-2.0) ratio, but the problem of high energy consumption when water vapor is introduced still exists.
  • the catalysts of the above systems all use cerium, chromium, manganese and other metal oxides or rare earth elements as additives. Some of them, such as chromium oxides, not only increase the cost of the catalyst, but also have a greater impact on the environment and even human health. Great harm.
  • hexagonal boron nitride (h-BN) is considered to be an emerging characteristic material in the field of heterogeneous catalysis because of its strong thermal stability, strong oxidation resistance and high thermal conductivity.
  • h - BN has a structure similar to C3N4 and is a metal-free catalyst for alkane dehydrogenation, especially carbon-doped BN nanosheets in propane dehydrogenation and ethylbenzene-carbon dioxide oxidative dehydrogenation (Angew. Chem.Int.Ed., 2017, 56, 8231-8235; J.Energy.Chem.Doi: 10.1016/j.jechem.2020.03.027), greatly enriched heteroatom-doped two-dimensional metal-free materials Application in the field of catalytic alkane dehydrogenation. Some materials such as commercial boron carbide (CN109126843A) also showed higher stability, but lower activity.
  • boron nitride-based catalysts prepared by the research group are mostly powder-based, with a particle size of 100-200 mesh, which is not convenient for kilogram-level preparation and application in actual production, and its practical value is limited; and long-term operation, carbon deposition The phenomenon of deactivation still exists; and there is still room for improvement in the selectivity of the catalyst.
  • the first purpose of the present invention is to provide an alkane dehydrogenation
  • the preparation method of the hydrogen-to-olefins catalyst aims to improve product selectivity, carbon deposition resistance and long-term stability while maintaining a good conversion rate.
  • the second purpose of the present invention is to provide the catalyst prepared by the preparation method.
  • the third object of the present invention is to provide a method for alkane dehydrogenation using the catalyst prepared by the preparation method.
  • a preparation method of a catalyst for alkane dehydrogenation to olefins which is to recrystallize the compound raw materials that can provide B, P, S, and N elements in a solvent, and then recrystallize the recrystallized product in an atmosphere containing ammonia at a temperature greater than or equal to 5
  • the temperature is raised to 700-1000°C at a heating rate of °C/min, and heat preservation is carried out to obtain the catalyst;
  • the S:B element molar ratio in the compound raw material is greater than or equal to 10;
  • the N:B element molar ratio is 10 or more.
  • the technical solution of the present invention innovatively uses S and P compounds to participate in the in-situ preparation of boron nitride, and is further based on the raw material form, B:S element ratio, B:P element ratio and roasting mechanism (such as heating rate and roasting temperature) Synergistic control can unexpectedly obtain a new catalyst with P modification, special microstructure and excellent catalytic performance.
  • boron nitride is synthesized in situ with the synergistic assistance of S and P, and the synergistic control of the raw material form, ratio and roasting mechanism is to improve the microstructure of the prepared catalyst and improve its dehydrogenation process.
  • the P and S elements need to be introduced in the form of compounds, which can unexpectedly cooperate with other conditions, thereby improving the microstructure of the prepared material and improving its dehydrogenation performance.
  • the compound raw materials include a boron source, a phosphorus source, a sulfur source and a nitrogen source, wherein the boron source is a boron compound that can provide boron;
  • the phosphorus source is a phosphorus compound that can provide phosphorus
  • the sulfur source is a sulfur compound capable of providing elemental sulfur
  • the nitrogen source is a nitrogen compound that can provide nitrogen.
  • the raw material can be a compound that only provides one element among B, P, S, and N, or a compound that can provide two or more elements among B, P, S, and N,
  • a compound containing two elements, N and S can be used as both a nitrogen source and a sulfur source.
  • the sulfur source is one or more of thiourea, thioethylthiourea, ammonium thiosulfate and ammonium sulfate.
  • the preferred sulfur source compound and other conditions are unexpectedly synergistic, which can unexpectedly improve the microstructure of the prepared catalyst and improve the performance of the catalyst.
  • the sulfur source is thiourea.
  • Preferred compounds can further improve the synergistic effect of the technical solution of the present invention, and contribute to unexpectedly further improving the performance of the prepared catalyst.
  • the phosphorus source is at least one of hydroxyethylidene diphosphate, hexachlorotrimeric phosphazene and ammonium dihydrogen phosphate.
  • the boron source is selected from at least one of boric acid and boron oxide.
  • the nitrogen source is at least one of urea, cyanamide, dicyandiamide, thiourea and melamine.
  • the combined control of the B, P, and S elements in the raw materials can unexpectedly further improve the microstructure of the prepared material, improve the P-modified hybridization, improve its catalytic performance, and especially help to improve the product selective.
  • the S:B element molar ratio is 10-90:1; more preferably 16-60:1; still more preferably 20-60:1; most preferably 28-60:1.
  • the molar ratio of P:B element is 0.5-2:1; more preferably 1-2:1; still more preferably 1-1.4:1.
  • the molar ratio of N:B is 10-200:1; more preferably 30-130:1; still more preferably 40-120:1.
  • the compound capable of providing B, S, P and N elements can be recrystallized in a solvent.
  • a solvent can be water;
  • the recrystallization temperature is 30-90°C, more preferably 40-90°C; even more preferably 50-80°C.
  • the product obtained by recrystallization is roasted in an ammonia-containing atmosphere. It is found that benefiting from the assistance of the S and P compounds, further matching the heating rate and temperature can improve the synergy and improve the obtained material. Catalytic properties, especially help to improve the selectivity and stability of the prepared materials.
  • the heating rate is 5-15°C/min; more preferably 5-10°C/min; further preferably 5-7.5°C/min.
  • the amount of ammonia gas introduced into the ammonia-containing atmosphere is 5-100 mL/min; more preferably 5-80 mL/min; still more preferably 40-60 mL/min.
  • the firing temperature is 700°C to 900°C; more preferably 800°C to 900°C.
  • the time for heat preservation and roasting is greater than or equal to 2 hours; preferably 2 to 5 hours.
  • the preferred preparation method of the present invention is obtained by recrystallizing the raw material aqueous solution of boron source, nitrogen source, phosphorus source and sulfur source, followed by drying and roasting the recrystallized product under ammonia atmosphere.
  • the phosphorus source is one or more compounds of hydroxyethylidene diphosphate monohydrate, hexachlorotripolyphosphazene, and ammonium dihydrogen phosphate;
  • the sulfur source is thiourea, thioethylthiourea , one or more of ammonium sulfate, ammonium thiosulfate;
  • the boron source is selected from one of boric acid, boron oxide;
  • the nitrogen source is selected from urea, cyanamide, dicyandiamine, One or several kinds of melamine.
  • the recrystallization temperature of the raw material liquid is 40-90°C; the vacuum drying temperature of the recrystallized product is 50-80°C, and the drying time is 10-20h; The amount is 5-100mL/min, the heating rate is 5-15°C/min, the calcination temperature is 700-900°C, and the calcination time is 2-5h.
  • the catalyst can also be supported on a carrier.
  • the carrier can be a carrier known in the industry, and can be prepared by using a known loading method in the industry.
  • the carrier is at least one of aluminum oxide, silicon dioxide or other carrier containing one of the two components;
  • the steps of the load are as follows:
  • the compound raw materials that can provide B, P, S and N elements, formaldehyde and precursor raw materials that can be converted into carriers are recrystallized in a solvent, and then the recrystallized products are subjected to the gradient roasting to obtain.
  • the preparation of another supported catalyst of the present invention is, for example: mixing the carrier and the synthetic raw materials to carry out the recrystallization and roasting treatment to obtain final product.
  • the invention also includes the catalyst prepared by the preparation method.
  • the catalyst can be in the form of nanometer, micron or millimeter-scale powder, or in a structured form with a larger size and further obtained by means of self-forming.
  • the innovative preparation method of the present invention is based on compound S and P participating in the in-situ synthesis of BN, and based on the combined control of conditions, it can contribute to the modification of P and the control of the modified form, in addition, it can also have the effect of compound S , to control the microstructure of materials, can unexpectedly obtain new materials with special chemical and physical structures.
  • the invention also discloses a method for producing alkenes by dehydrogenating alkanes.
  • the raw materials of alkanes are contacted with the catalyst prepared by the preparation method to carry out dehydrogenation reaction to prepare corresponding alkenes products.
  • the direct dehydrogenation or oxidative dehydrogenation of alkanes can be realized, and the corresponding alkenes can be efficiently obtained, and have good conversion rate, product selectivity and stability.
  • the alkane feedstock is a compound of formula 1:
  • R 1 to R 4 are independently H, C 1 to C 10 alkyl, C 3 to C 10 cycloalkyl or aryl; or, R 1 and R 4 are ringed with each other to form a ring group;
  • the alkyl group, cycloalkyl group, ring group or aryl group are allowed to have substituents, which are respectively substituted alkyl group, substituted cycloalkyl group, substituted ring group, and substituted aryl group; wherein, the described substituent group is C At least one substituent selected from 1 to C 6 alkyl, C 1 to C 6 alkoxy, halogen, phenyl, nitro, and trifluoromethyl.
  • the alkyl group described in the present invention is a straight chain or branched chain alkyl group.
  • the cycloalkyl group is a three- to six-membered monocyclic ring, a spiro ring or a bridged ring.
  • the aryl group is a benzene ring, a five-membered heterocyclic aryl group, a six-membered heterocyclic aryl group, or a combination of two or more aromatic rings in a benzene ring, a five-membered heterocyclic aryl group, or a six-membered heterocyclic aryl group. condensed rings formed.
  • the R 1 and R 4 are ringed with each other to form a ring group, and the ring group is, for example, a five-membered or six-membered ring.
  • the alkane raw material structure after cyclization is, for example,
  • formula 1 is directly or oxidatively dehydrogenated to obtain the olefin product of formula 2
  • the alkane raw material is a compound having the structure of formula 1-1;
  • R 1 is H, C 1 -C 6 alkyl, phenyl or substituted phenyl; the phenyl ring of the substituted phenyl contains C 1 -C 6 alkyl, C 1 -C 6 At least one substituent of C6 alkoxy, halogen, phenyl, nitro, trifluoromethyl.
  • the dehydrogenation reaction is carried out under anhydrous conditions; or under an atmosphere containing weak oxygen.
  • the oxygen content of the weak oxygen-containing atmosphere is, for example, not higher than 10 vol.%; for example, it can be 1-5 vol.%.
  • the dehydrogenation reaction is carried out under an oxygen atmosphere or an oxygen-free atmosphere;
  • the temperature of the dehydrogenation reaction is 500-700°C; preferably 550-650°C; more preferably 600-650°C.
  • the dehydrogenation reaction can be realized based on existing reaction equipment, for example, it can be filled into a reactor, and a gas-solid phase catalytic reaction can be performed.
  • All groups can be used as active groups in this reaction; moreover, the microstructure of the catalyst has a significant impact on selectivity and stability; by introducing sulfur and phosphorus compounds during the in-situ synthesis of boron nitride, based on sulfur compounds and phosphorus compounds And the synergy of conditions can improve the modification of P, and at the same time can regulate the microstructure of the material, which in turn helps to improve the catalytic performance of the prepared material.
  • the invention innovates in-situ synthesis of boron nitride under the synergy of sulfur-phosphorus compounds, and further based on the synergy of S, P material form, content and roasting mechanism, it can improve the modification of P to BN. In addition, there are It helps to regulate the microstructure, and then while maintaining a good conversion rate, it can significantly improve the selectivity of the product, improve the problem of carbon deposition, and improve the stability of the catalyst.
  • the present invention takes typical ethylbenzene dehydrogenation as an example, the amount of styrene produced per unit catalyst and unit time can reach 24.33mmol/(g ⁇ h), the selectivity of styrene is greater than 97%, and the stable operation is more than 100 hours. For the industrialization reaction with practical significance, it has important economic value, environmental protection value and social value.
  • the structured catalyst has better mechanical strength and formability, which can meet the production technology requirements of different conditions.
  • the catalyst of the present invention has the advantages of high temperature resistance, stronger carbon deposition resistance, simple preparation process, and no metal pollution, and has a very good industrial application prospect .
  • the nitrogen adsorption-desorption curve of the prepared material has an H3 hysteresis loop, that is, there is a slit pore structure, and the specific surface area is 101.13m 2 /g.
  • the specific surface area (140-260m 2 /g) of BNP-1.2 (comparative example 1) in the previous work combined with the pore size analysis, the average pore size of the material is 13.39nm, which is much larger than the pore size of BNP-1.2 (3nm), so it is better than The surface area is lower than BNP-1.2.
  • the XPS test in Figure 3 found that the atomic percentage of S is lower than the detection line of the instrument, that is, it is difficult for S to enter the BN framework or surface, so it can be inferred that the role of the S source mainly affects the microstructure of the catalyst during the heat treatment of the material. form.
  • the test method of the catalyst performance is: 50mg of the catalyst is added to 2mL of quartz sand with a particle size of 40-60 mesh to dilute, put into a ⁇ 8mm fixed-bed quartz reaction tube, and both ends of the catalyst bed are blocked with a small amount of quartz wool. Inject 20 mL/min of nitrogen to provide an inert gas atmosphere. Under the protection of nitrogen, the temperature was raised to 600°C at a rate of 4°C/min, and the catalyst was stabilized for 30 minutes to preactivate the catalyst, and then a mixed raw material gas with a volume fraction of 2.8% ethylbenzene was introduced at a flow rate of 20mL/min for continuous reaction.
  • the reaction product was collected with ethanol at 5°C, and its composition was analyzed by Shimadzu GC-2010Plus gas chromatograph, the column model was RTX-5, and the detector was FID.
  • the initial conversion rate of ethylbenzene is 77.43%
  • the selectivity of styrene is 97.25%
  • the corresponding amount of styrene generated per unit time on the catalyst is 22.72mmol/(g ⁇ h), which can be stable for more than 40 hours.
  • Example 1 Compared with Example 1, the only difference is that the composition of the sulfur source was changed, and ammonium thiosulfate and ammonium sulfate were used for research respectively. Wherein, when ammonium thiosulfate was used as the sulfur source, urea was used as a supplementary nitrogen source, and urea was used as a supplementary nitrogen source. The ratio of control B:N remains unchanged, and other parameters and operations are the same as in Example 1.
  • Example 1 Compared with Example 1, the only difference is that the molar ratio of the sulfur source is changed, respectively, the molar ratios of B:S are 1:16, 1:20, 1:24, 1:28, and urea is used to supplement nitrogen Source, to keep B:N unchanged, in addition, the molar ratio of B:S is 1:60 in the case, no additional urea is added as a nitrogen source; other parameters and operations are the same as in Example 1.
  • Adopt the catalyst performance test method in embodiment 1 record the performance of catalyst as shown in table 2:
  • Example 1 Compared with Example 1, the only difference is that the composition of the phosphorus source was changed, and ammonium dihydrogen phosphate and hexachlorotrimeric phosphazene were used for research, and other parameters and operations were the same as in Example 1.
  • Example 1 Compared with Example 1, the only difference is that the molar ratio of the phosphorus source is changed, the molar ratios of B:P are respectively 1:1.0 and 1:1.4, and other parameters and operations are the same as in Example 1.
  • Example 1 Compared with Example 1, the heating rate (the rate of heating up to the calcination temperature) was changed to 7.5°C/min and 10°C/min respectively, and other parameters and operations were the same as in Example 1.
  • Adopt the catalyst performance test method in embodiment 1 record the performance of catalyst as shown in table 5:
  • Example 1 Compared with Example 1, the firing temperature was changed to 600°C, 700°C, and 900°C respectively, and other parameters and operations were the same as in Example 1.
  • Example 2 Compared with ammonium thiosulfate as the sulfur source in Example 2, the only difference is that the N sources are supplemented with cyanamide and dicyandiamide respectively, and other parameters and operations are the same as in Example 1.
  • Example 2 Compared with Example 1, the nitrogen flow rate, heating rate and roasting temperature (80mL/min, 10°C/min, 900°C) were changed at the same time.
  • the performance of the catalyst is measured as follows: the initial ethylbenzene conversion rate is 63.09%, the styrene selectivity is 97.33%, and the styrene production amount realized per unit time on the corresponding unit catalyst is 18.53mmol /(g ⁇ h), can be stable for more than 40 hours.
  • Embodiment 11 (compared with embodiment 1, the structured catalyst prepared by loading method)
  • Example 1 Compared with Example 1, 20-40 mesh activated alumina particles were added to the mixed solution of boric acid, thiourea, and hydroxyethylidene diphosphonic acid monohydrate, and other steps remained unchanged.
  • the catalyst is recorded as: BNP@alumina/HEDP-48/1.2.
  • the performance of the catalyst is measured as follows: the initial ethylbenzene conversion rate is 82.50%, the styrene selectivity is 97.72%, and the styrene production amount realized per unit time on the corresponding unit catalyst is 24.33mmol /(g ⁇ h), can be stable for more than 100 hours.
  • Embodiment 12 (oxidative dehydrogenation)
  • the catalyst of Example 1 was applied to oxidative dehydrogenation under weak oxygen atmosphere.
  • the nitrogen of 20ml/min is changed into the nitrogen-oxygen mixture containing oxygen 3% (volume percent), and the performance of recording catalyst is: initial ethylbenzene conversion rate 78.35%,
  • the selectivity of styrene is 94.60%, and the corresponding amount of styrene produced per unit time on the catalyst is 22.36mmol/(g ⁇ h), which can be stable for more than 100 hours.
  • Example 1 Compared with Example 1, the only difference is that the temperatures of the dehydrogenation reaction process are 550°C, 575°C, and 625°C respectively, and other parameters and operations are the same as in Example 1.
  • Example 2 Compared with Example 1, the main reason is that no sulfur source is added, and the nitrogen source is replaced by urea.
  • the specific steps are the same as Example 1 with application number 201910739798.4; the catalyst is recorded as BNP 1.2.
  • the catalytic effect of this comparative example is: the initial conversion rate of ethylbenzene is 62.42%, and the selectivity of styrene is 93.54%. hours or more. Its effect is significantly worse than that of Example 1, and the selectivity of the product is worse than that of the embodiment of the present invention.
  • Example 1 Compared with Example 1, the only difference is that elemental sulfur is used (sublimed sulfur, the added molar weight is the same as that of Example 1; the N source is provided by urea, and the molar weight of the N source is the same as that of Example 1), and other conditions are the same as in Example 1.
  • the catalyst is recorded as: BNSP-sublimed sulfur/HEDP-48/1.2.
  • the performance of the catalyst was measured as follows: the initial ethylbenzene conversion rate was 22.36%, and the styrene selectivity was 93.71%. The corresponding amount of styrene produced per unit time on the catalyst is 6.32 mmol/(g ⁇ h).
  • Example 1 Compared with Example 1, the only difference is that no phosphorus source is added.
  • the catalyst is recorded as: BNS-48.
  • the performance of the catalyst was measured as: 29.73%, and the selectivity to styrene was 97.68%.
  • the corresponding amount of styrene produced per unit time on the unit catalyst is 8.76mmol/(g ⁇ h), which can be stable for more than 20 hours. Its effect is significantly worse than that of Example 1, mainly because the conversion rate of the product is worse than that of the embodiment of the present invention.
  • Example 1 Compared with Example 1, the only difference is that the phosphorus source is phosphorus simple substance (red phosphorus, the added molar amount is the same as that of Example 1).
  • the catalyst is recorded as: BNSP-thiourea/P-48-1.2.
  • the performance of the catalyst was measured as follows: the initial ethylbenzene conversion rate was 20.04%, and the styrene selectivity was 90.68%. The corresponding amount of styrene produced per unit time on the catalyst is 5.48 mmol/(g ⁇ h).
  • Example 1 Compared with Example 1 and Example 5, the only difference is that the molar ratio of boron element to phosphorus element is 1:0.2), and the catalyst is recorded as: BNSP-thiourea/HEDP-48/0.2.
  • the performance of the catalyst is measured as follows: the initial conversion rate of ethylbenzene is 28.42%, the selectivity of styrene is 95.31%, and the amount of styrene generated per unit time on the corresponding unit catalyst is 8.17mmol /(g ⁇ h).
  • Example 1 Compared with Example 1 and Example 6, the only difference is that the heating rate is 1° C./min.
  • the performance of the catalyst was measured as follows: the initial ethylbenzene conversion rate was 46.59%, and the styrene selectivity was 92.42%.
  • the amount of styrene produced per unit time on the corresponding unit catalyst is 12.99mmol/(g h), which can be stable for more than 20 hours.
  • Example 1 Compared with Example 1 and Example 7, the only difference is that the firing temperature is 1100°C.
  • the performance of the catalyst was measured as follows: the initial ethylbenzene conversion rate was 50.33%, and the styrene selectivity was 83.03%.
  • the corresponding amount of styrene produced per unit time on the unit catalyst is 12.61 mmol/(g ⁇ h), which can be stabilized for more than 20 hours.
  • Example 1 Compared with Example 1, the difference is mainly that BN is directly synthesized without adding a phosphorus source and a sulfur source (the synthesis method is the same as in Example 1, for example, using B to sinter under an ammonia atmosphere); then BN and sulfur The source (thiourea) and the P source were mixed in proportion, and further heat-treated under a nitrogen protective atmosphere.
  • the catalyst performance testing method in Example 1 the performance of the catalyst was measured as follows: the initial ethylbenzene conversion rate was 18.51%, and the styrene selectivity was 85.47%.
  • the corresponding amount of styrene produced per unit time on the unit catalyst is 4.77mmol/(g ⁇ h), which can be stabilized for more than 20 hours.
  • Example 2 Measure 2mL of quartz sand with a particle size of 40 to 60 meshes, and use the catalyst performance test method in Example 1 to measure the performance of the catalyst: the initial ethylbenzene conversion rate is 8.82%, and the styrene selectivity is 58.33%. The amount of styrene produced per unit time was 1.55 mmol/(g ⁇ h).
  • the doping of sulfur element can significantly improve the selectivity of the phosphorus nitrogen boron catalyst to styrene.
  • the joint addition of sulfur source and phosphorus source is one of the keys to obtain high-performance catalysts.
  • the type of sulfur source, the type of phosphorus source, and the amount added are the second key to obtaining a high-performance catalyst.
  • the heating system is the third key to obtain high-performance catalysts.
  • the catalyst is a distinctly porous material. Sulfur element mainly affects the formation of pore structure in the catalyst synthesis process. The pore structure of the catalyst is more reasonable, the kinetics is beneficial to the transfer and conversion of intermediates, and the occurrence of side reactions is avoided.

Abstract

The present invention belongs to the technical field of catalytic dehydrogenation, and particularly discloses a preparation method for a catalyst for the dehydrogenation of alkanes into olefins, which comprises: recrystallizing a compound raw material capable of providing B, P, S and N elements in a solvent, heating the recrystallized product to 700-1000ºC in an ammonia-containing atmosphere at a heating rate of greater than or equal to 5ºC/min, and carrying out heat preservation and roasting to obtain the catalyst. In the compound raw material, the molar ratio of S:B is greater than or equal to 10; the molar ratio of P:B is greater than or equal to 0.5; and the molar ratio of N:B is greater than or equal to 10. The present invention also includes the catalyst prepared by the preparation method and the use of the catalyst in the preparation of olefins by means of direct or oxidative dehydrogenation of alkanes. According to the preparation method of the present invention, a special catalyst can be obtained, and the catalyst has a good conversion rate, as well as excellent product selectivity and stability.

Description

烷烃脱氢制烯烃催化剂及其制备和脱氢方法Catalyst for dehydrogenating alkanes to olefins and its preparation and dehydrogenation method 技术领域technical field
本发明属于化学合成领域，具体涉及一种烷烃脱氢制备烯烃的催化剂及脱氢方法。The invention belongs to the field of chemical synthesis, and in particular relates to a catalyst for preparing alkenes by dehydrogenating alkanes and a dehydrogenation method.
背景技术Background technique
烯烃是重要的化工原料，例如苯乙烯作为芳烃的衍生物，是化工行业生产高聚物重要的单体原料，被广泛应用于和人们日常生活密切相关的领域中。据估计，每年苯乙烯相关的工业产值可达600亿美元。近20年来，随着全球苯乙烯下游产品市场的不断开拓，苯乙烯需求量逐年上升。虽然从国际市场来说苯乙烯的产能有所富裕，但我国作为苯乙烯需求增速最快的国家之一，苯乙烯自给率仍处于较低水平。相关数据显示，到2022年我国苯乙烯生产能力将超过1500万吨/年，而根据目前己知的下游装置新、扩、拟建计划，下游装置苯乙烯表观需求量将达到1800～1900万吨/年，缺口仍然超过300万吨/年。在反倾销、贸易战的大背景下，我国苯乙烯进口附加税大幅上涨，这意味着开发新的苯乙烯生产技术，尤其是自主研发高性能、低成本、低能耗的乙苯脱氢制苯乙烯催化剂，对于提高国内苯乙烯自给率具有重要的意义又富有挑战性。Olefins are important chemical raw materials. For example, styrene, as a derivative of aromatic hydrocarbons, is an important monomer raw material for the production of high polymers in the chemical industry, and is widely used in fields closely related to people's daily life. It is estimated that the annual industrial output value related to styrene can reach 60 billion US dollars. In the past 20 years, with the continuous development of the global styrene downstream product market, the demand for styrene has increased year by year. Although the production capacity of styrene is affluent from the international market, my country is one of the countries with the fastest growth rate of styrene demand, and the styrene self-sufficiency rate is still at a low level. Relevant data show that by 2022, my country's styrene production capacity will exceed 15 million tons per year, and according to the currently known plans for new, expanded and planned downstream devices, the apparent demand for styrene in downstream devices will reach 18-19 million tons/year, the gap still exceeds 3 million tons/year. Against the backdrop of anti-dumping and trade wars, my country’s styrene import surtax has risen sharply, which means developing new styrene production technologies, especially the independent research and development of high-performance, low-cost, and low-energy Ethylbenzene Dehydrogenation to Styrene Catalyst is of great significance and challenging to improve the domestic styrene self-sufficiency rate.
在实际生产过程中，考虑到乙苯脱氢制备苯乙烯的反应为分子数增加的强吸热反应，受热力学平衡限制较大，低压和高温条件下有利于提高反应转化率。1937年，美国陶氏化学公司(Dow)和德国巴斯夫公司(BASF)同时实现了乙苯脱氢制取苯乙烯的工业化生产。经过80多年的发展，目前工业上应用的苯乙烯生产方法主要有两种：乙苯直接脱氢法和苯乙烯环氧乙烷联产法，而乙苯催化脱氢催化剂也已由初期使用的锌系、镁系催化剂逐步被综合性能更为优异的铁系催化剂所取代。当前，使用含钾氧化铁或氧化锌作为催化剂、在600～650℃的高温和过量水蒸气(水/烃比7～15)保护下催化乙苯直接脱氢生产苯乙烯的 Lummus/Monsanto/UOP工艺是现目前世界上应用最为广泛的苯乙烯生产技术，该项技术研究至今已有70多年的历史，相应的研究成果也得到了广泛的认可，采用该工艺生产的苯乙烯量占全球苯乙烯生产总量的90％以上。但水蒸气的大量消耗，使得整个生产过程能耗巨大。此外，考虑到温度过高会加剧苯乙烯的聚合，且钾在高温下不稳定，容易向低温区或催化剂颗粒中心转移，导致催化剂的稳定性变差。In the actual production process, considering that the reaction of dehydrogenation of ethylbenzene to prepare styrene is a strong endothermic reaction with an increase in the number of molecules, which is greatly restricted by thermodynamic equilibrium, the conditions of low pressure and high temperature are conducive to improving the reaction conversion rate. In 1937, the American Dow Chemical Company (Dow) and the German BASF Company (BASF) simultaneously realized the industrial production of ethylbenzene dehydrogenation to produce styrene. After more than 80 years of development, there are two main styrene production methods currently used in industry: direct dehydrogenation of ethylbenzene and co-production of styrene-ethylene oxide, and the catalytic dehydrogenation catalyst of ethylbenzene has also been used in the early stage. Zinc-based and magnesium-based catalysts are gradually replaced by iron-based catalysts with better comprehensive performance. Currently, Lummus/Monsanto/UOP that uses potassium-containing iron oxide or zinc oxide as a catalyst to catalyze the direct dehydrogenation of ethylbenzene to produce styrene at a high temperature of 600-650°C and under the protection of excess water vapor (water/hydrocarbon ratio 7-15) The process is currently the most widely used styrene production technology in the world. This technology research has a history of more than 70 years, and the corresponding research results have also been widely recognized. More than 90% of the total production. However, the large consumption of water vapor makes the whole production process consume a lot of energy. In addition, considering that the polymerization of styrene will be intensified if the temperature is too high, and potassium is unstable at high temperature, and it is easy to transfer to the low temperature region or the center of the catalyst particle, resulting in poor stability of the catalyst.
目前，国外最大的乙苯催化脱氢催化剂供应商是德国南方化学公司和美国标准催化剂公司，德国巴斯夫公司和陶氏化学公司也仍在生产该类催化剂。就南方化学公司来说，其新推出的Styromax系列催化剂已取代了早期生产的G-64、G-84和G-97系列催化剂。美国标准催化剂公司的乙苯催化脱氢催化剂也开发较早，尤其是Shell-105曾长期应用于各大型生产装置。近年来，标准公司为适应生产装置的要求，又相继推出C-035、C-045、C-145和Flexi Cat yellow/blue等催化剂。我国乙苯催化脱氢催化剂的自主研究始于20世纪60年代，中田石油集团石油化工研究院兰州化工研究中心研发的LH系列和厦门大学的XH系列、中科院大连化学物理研究物所开发的DC系列和中国石化上海石油化工研究院开发的GS系列催化剂均已实现工业应用。如：CN106423187A、CN106423240A、CN105312059A及CN105749934A。特别是专利CN105749934A报道的催化剂可在相对较低的水/烃(1.2～2.0)比下使用，但引入水蒸气时的高能耗问题仍然存在。此外，以上体系的催化剂，均以铈、铬、锰等金属的氧化或稀土元素做助剂，它们中的部分物质，如铬氧化物既提高了催化剂成本，也对环境甚至人类健康都有较大危害。另一方面，催化脱氢工艺的改进，如提高单程转化率和降低热能的使用己接近极限，而氧化脱氢体系中则存在苯乙烯深度氧化、反应选择性不高以及实际操作中反应物组成受***极限范围的限制等问题，也从一定程度上限制了脱氢反应的转化率。在上述背景下，开发高转化率、高选择性、高稳定性和环境友好型的催化剂，尤其是开发出适用于无水或低水/烃比条件下操作的催化剂，对苯乙烯生产过程中的节能降耗具有重要意义。At present, the largest foreign suppliers of catalytic dehydrogenation catalysts for ethylbenzene are German Südchemical Company and American Standard Catalyst Company, and German BASF Company and Dow Chemical Company are still producing such catalysts. As far as Southern Chemical Company is concerned, its newly launched Styromax series catalysts have replaced the G-64, G-84 and G-97 series catalysts produced earlier. The ethylbenzene catalytic dehydrogenation catalyst of American Standard Catalyst Company was also developed earlier, especially Shell-105, which has been used in various large-scale production devices for a long time. In recent years, in order to meet the requirements of production equipment, Standard Company has successively launched catalysts such as C-035, C-045, C-145 and Flexi Cat yellow/blue. my country's independent research on ethylbenzene catalytic dehydrogenation catalysts began in the 1960s. The LH series developed by the Lanzhou Chemical Research Center of the Petrochemical Research Institute of Zhongtian Petroleum Group, the XH series developed by Xiamen University, and the DC series developed by the Dalian Institute of Chemical Physics, Chinese Academy of Sciences And the GS series catalysts developed by Sinopec Shanghai Petrochemical Research Institute have achieved industrial applications. Such as: CN106423187A, CN106423240A, CN105312059A and CN105749934A. In particular, the catalyst reported in patent CN105749934A can be used at a relatively low water/hydrocarbon (1.2-2.0) ratio, but the problem of high energy consumption when water vapor is introduced still exists. In addition, the catalysts of the above systems all use cerium, chromium, manganese and other metal oxides or rare earth elements as additives. Some of them, such as chromium oxides, not only increase the cost of the catalyst, but also have a greater impact on the environment and even human health. Great harm. On the other hand, the improvement of the catalytic dehydrogenation process, such as increasing the single-pass conversion rate and reducing the use of heat energy, is approaching the limit, while in the oxidative dehydrogenation system, there are deep oxidation of styrene, low reaction selectivity, and the composition of reactants in actual operation. Problems such as the limitation of the explosion limit range also limit the conversion rate of the dehydrogenation reaction to a certain extent. In the above background, the development of catalysts with high conversion, high selectivity, high stability and environmental friendliness, especially the development of catalysts suitable for operation under conditions of anhydrous or low water/hydrocarbon ratio, is of great importance to the production process of styrene Energy saving is of great significance.
近年来，非金属催化剂的探索成为研究的热点。特别是具有规整结构的、元素多变的二维材料的出现，为烷烃脱氢催化剂的研究，提供了更多的可能性。2010年，中国科学院沈阳金属研究所苏党生课题组首次报道了纳米金刚石(ND)可作 为无水蒸气条件下催化乙苯直接脱氢制备苯乙烯的高效非金属催化剂，并认为具有较高氧原子电子密度的不饱和酮/二酮型羰基(C＝O)是该催化剂的活性中心。这项工作掀起了有关碳基催化剂应用于乙苯脱氢反应的研究热潮。之后，中科院沈阳金属所以及大连理工大学在此基础上，又陆续报道了碳纳米管(新型炭材料,2013,28,5,336-341)、纳米金刚石(ChemSusChem,2016,9,662-666)、氮化碳(J.Mater.Chem.A,2014,2,13442-13451)以及其复配制得的纳米金刚石/氮化碳(Appl.Catal.A：Gen.,2019,571,82-88；Mater.Chem.A,2014,2,13442–13451)催化剂在无水无氧或无水低氧条件下催化乙苯直接脱氢制备苯乙烯的反应中，表现出较好的活性与选择性；到目前为止，人们已经认识到氮原子掺杂到碳基体中可以向非定域π-体系提供额外的电子，并提高碳材料中C＝O的化学反应活性。除碳材料外，六方氮化硼(h-BN)因具有热稳定性强、抗氧化性能强和热导率高等特点而被认为是多相催化领域中一种新兴的特色材料，它可以在高放热反应(如F-T合成)中快速消散反应热。据报道，h-BN结构与C 3N 4相似，是一种用于烷烃脱氢的无金属催化剂，尤其是碳掺杂BN纳米片在丙烷脱氢和乙苯-二氧化碳氧化脱氢(Angew.Chem.Int.Ed.,2017,56,8231-8235；J.Energy.Chem.Doi:10.1016/j.jechem.2020.03.027)中的应用，极大地丰富了杂原子掺杂二维无金属材料在催化烷烃脱氢领域的应用。部分材料如商业碳化硼(CN109126843A)也表现出了较高的稳定性，但活性较低。 In recent years, the exploration of metal-free catalysts has become a research hotspot. In particular, the emergence of two-dimensional materials with regular structures and variable elements provides more possibilities for the research of alkane dehydrogenation catalysts. In 2010, the research group of Su Dangsheng, Shenyang Institute of Metal Research, Chinese Academy of Sciences reported for the first time that nanodiamond (ND) can be used as an efficient non-metallic catalyst for the direct dehydrogenation of ethylbenzene to styrene under the condition of no water vapor, and it is believed that it has a high oxygen The unsaturated ketone/diketone carbonyl group (C=O) with atomic electron density is the active center of the catalyst. This work set off an upsurge of research on the application of carbon-based catalysts to the dehydrogenation of ethylbenzene. After that, Shenyang Institute of Metals, Chinese Academy of Sciences and Dalian University of Technology successively reported carbon nanotubes (new carbon materials, 2013, 28, 5, 336-341), nanodiamonds (ChemSusChem, 2016, 9, 662-666), nitride Carbon (J.Mater.Chem.A, 2014, 2, 13442-13451) and its compounded nano-diamond/carbon nitride (Appl.Catal.A: Gen., 2019, 571, 82-88; Mater. Chem.A, 2014, 2, 13442–13451) catalysts have shown good activity and selectivity in the reaction of direct dehydrogenation of ethylbenzene to styrene under anhydrous anoxic or anhydrous hypoxic conditions; So far, it has been recognized that the doping of nitrogen atoms into the carbon matrix can provide additional electrons to the delocalized π-system and enhance the chemical reactivity of C=O in carbon materials. In addition to carbon materials, hexagonal boron nitride (h-BN) is considered to be an emerging characteristic material in the field of heterogeneous catalysis because of its strong thermal stability, strong oxidation resistance and high thermal conductivity. Rapid dissipation of heat of reaction in highly exothermic reactions such as FT synthesis. It has been reported that h - BN has a structure similar to C3N4 and is a metal-free catalyst for alkane dehydrogenation, especially carbon-doped BN nanosheets in propane dehydrogenation and ethylbenzene-carbon dioxide oxidative dehydrogenation (Angew. Chem.Int.Ed., 2017, 56, 8231-8235; J.Energy.Chem.Doi: 10.1016/j.jechem.2020.03.027), greatly enriched heteroatom-doped two-dimensional metal-free materials Application in the field of catalytic alkane dehydrogenation. Some materials such as commercial boron carbide (CN109126843A) also showed higher stability, but lower activity.
上述工作极大地拓展了非金属催化剂在乙苯脱氢中的应用，特别是无水条件下直接脱氢制备苯乙烯催化剂的研究。但是由于掺氮碳材料在高温下易于分解，因此大多报道该类催化剂限于在550℃以下应用，使得催化剂的活性、稳定性都不太理想。此外，与无水无氧脱氢相比，无水有氧脱氢易于产生更多的副产物二氧化碳。因此，开发适用于无水条件下，特别是无水无氧条件下，具有耐高温、性能优越、制备工艺简单等优点的非金属脱氢催化剂，仍是目前研究的重点。The above work has greatly expanded the application of non-metallic catalysts in the dehydrogenation of ethylbenzene, especially the research on the preparation of styrene catalysts by direct dehydrogenation under anhydrous conditions. However, because nitrogen-doped carbon materials are easy to decompose at high temperatures, most reports of this type of catalyst are limited to applications below 550 °C, making the activity and stability of the catalyst not ideal. Furthermore, anhydrous aerobic dehydrogenation tends to produce more carbon dioxide as a by-product compared to anhydrous anoxic dehydrogenation. Therefore, the development of non-metal dehydrogenation catalysts suitable for anhydrous conditions, especially anhydrous and oxygen-free conditions, with high temperature resistance, superior performance, and simple preparation process is still the focus of current research.
申请人所在课题组的前期工作(CN 201910739798.4)发现，磷掺杂氮化硼是一类优异的乙苯脱氢非金属催化剂。但目前课题组制备的氮化硼基催化剂，多以粉末为主，粒径尺寸为100～200目，不便于公斤级制备和实际生产中的应用，实用价值受限；而且长期运行，积碳失活的现象依然存在；而且催化剂的选择性还有提升的空间。The previous work of the applicant's research group (CN 201910739798.4) found that phosphorus-doped boron nitride is an excellent non-metallic catalyst for ethylbenzene dehydrogenation. However, the boron nitride-based catalysts prepared by the research group are mostly powder-based, with a particle size of 100-200 mesh, which is not convenient for kilogram-level preparation and application in actual production, and its practical value is limited; and long-term operation, carbon deposition The phenomenon of deactivation still exists; and there is still room for improvement in the selectivity of the catalyst.
发明内容Contents of the invention
针对现有烷烃脱氢制烯烃催化剂(本发明也简称为催化剂)存在的催化选择性不理想、容易积碳，长期稳定性不理想等技术问题，本发明第一目的在于，提供一种烷烃脱氢制烯烃催化剂的制备方法，旨在保持良好转化率的同时，改善产物选择性、抗积碳性以及长期稳定性。Aiming at technical problems such as unsatisfactory catalytic selectivity, easy carbon deposition, and unsatisfactory long-term stability existing in the existing catalyst for alkane dehydrogenation to olefins (the present invention is also referred to as catalyst), the first purpose of the present invention is to provide an alkane dehydrogenation The preparation method of the hydrogen-to-olefins catalyst aims to improve product selectivity, carbon deposition resistance and long-term stability while maintaining a good conversion rate.
本发明第二目的在于，提供所述的制备方法制得的催化剂。The second purpose of the present invention is to provide the catalyst prepared by the preparation method.
本发明第三目的在于，提供所述的制备方法制得的催化剂的烷烃脱氢方法。The third object of the present invention is to provide a method for alkane dehydrogenation using the catalyst prepared by the preparation method.
一种烷烃脱氢制烯烃催化剂的制备方法，将能提供B、P、S、N元素的化合物原料在溶剂中进行重结晶，随后将重结晶产物在含氨气气氛内、在大于或等于5℃/min的升温速率下升温至700～1000℃，并进行保温焙烧，制得所述的催化剂；A preparation method of a catalyst for alkane dehydrogenation to olefins, which is to recrystallize the compound raw materials that can provide B, P, S, and N elements in a solvent, and then recrystallize the recrystallized product in an atmosphere containing ammonia at a temperature greater than or equal to 5 The temperature is raised to 700-1000°C at a heating rate of °C/min, and heat preservation is carried out to obtain the catalyst;
所述的化合物原料中S：B元素摩尔比为大于或等于10；The S:B element molar ratio in the compound raw material is greater than or equal to 10;
P：B元素摩尔比为大于或等于0.5；P: The molar ratio of B element is greater than or equal to 0.5;
N：B的元素摩尔比大于或等于10。The N:B element molar ratio is 10 or more.
本发明技术方案，创新地采用S、P化合物参与氮化硼的原位制备，并进一步基于原料形态、B：S元素比、B：P元素比以及焙烧机制(例如升温速率以及焙烧温度)的协同控制，能够意外地获得P修饰、且具有特殊微观结构、具有优异催化性能的全新催化剂。The technical solution of the present invention innovatively uses S and P compounds to participate in the in-situ preparation of boron nitride, and is further based on the raw material form, B:S element ratio, B:P element ratio and roasting mechanism (such as heating rate and roasting temperature) Synergistic control can unexpectedly obtain a new catalyst with P modification, special microstructure and excellent catalytic performance.
本发明中，在S和P的协同辅助下进行氮化硼原位合成，以及对所述的原料形态、比例和焙烧机制的协同控制是改善制得的催化剂微观结构，并改善其脱氢制烯烃性能的关键。In the present invention, boron nitride is synthesized in situ with the synergistic assistance of S and P, and the synergistic control of the raw material form, ratio and roasting mechanism is to improve the microstructure of the prepared catalyst and improve its dehydrogenation process. The key to olefin performance.
本发明中，所述的P、S元素需要通过化合物形态引入，如此能够意外地和其他条件协同，从而改善制得的材料的微观结构，并改善其脱氢性能。In the present invention, the P and S elements need to be introduced in the form of compounds, which can unexpectedly cooperate with other conditions, thereby improving the microstructure of the prepared material and improving its dehydrogenation performance.
作为优选，所述的化合物原料包括硼源、磷源、硫源和氮源，其中，所述的硼源为能够提供硼元素的硼化合物；Preferably, the compound raw materials include a boron source, a phosphorus source, a sulfur source and a nitrogen source, wherein the boron source is a boron compound that can provide boron;
所述的磷源为能够提供磷元素的磷化合物；The phosphorus source is a phosphorus compound that can provide phosphorus;
所述的硫源为能够提供硫元素的硫化合物；The sulfur source is a sulfur compound capable of providing elemental sulfur;
所述的氮源为能够提供氮元素的氮化合物。The nitrogen source is a nitrogen compound that can provide nitrogen.
本发明中，所述的原料可以是仅提供B、P、S、N中的一种元素的化合物，也可以是能够提供B、P、S、N中的两种及以上的元素的化合物，例如，含有N、 S两种元素的化合物既可以用作氮源也可以用作硫源。In the present invention, the raw material can be a compound that only provides one element among B, P, S, and N, or a compound that can provide two or more elements among B, P, S, and N, For example, a compound containing two elements, N and S, can be used as both a nitrogen source and a sulfur source.
优选地，所述的硫源为硫脲、硫代乙硫脲、硫代硫酸铵和硫酸铵中的一种或几种。研究发现，优选的硫源化合物，和其他条件具有意外地协同性，可意外地改善制得的催化剂的微观结构，改善催化剂的性能。进一步优选，所述的硫源为硫脲。优选的化合物能够进一步改善本发明技术方案的协同效果，有助于意外地进一步改善制得的催化剂的性能。Preferably, the sulfur source is one or more of thiourea, thioethylthiourea, ammonium thiosulfate and ammonium sulfate. The study found that the preferred sulfur source compound and other conditions are unexpectedly synergistic, which can unexpectedly improve the microstructure of the prepared catalyst and improve the performance of the catalyst. Further preferably, the sulfur source is thiourea. Preferred compounds can further improve the synergistic effect of the technical solution of the present invention, and contribute to unexpectedly further improving the performance of the prepared catalyst.
优选地，所述的磷源为羟基乙叉二磷酸、六氯三聚磷腈和磷酸二氢铵中的至少一种。Preferably, the phosphorus source is at least one of hydroxyethylidene diphosphate, hexachlorotrimeric phosphazene and ammonium dihydrogen phosphate.
优选地，所述的硼源选自硼酸和氧化硼中的至少一种。Preferably, the boron source is selected from at least one of boric acid and boron oxide.
优选地，所述的氮源为尿素、单氰胺、二氰胺、硫脲和三聚氰胺中的至少一种。Preferably, the nitrogen source is at least one of urea, cyanamide, dicyandiamide, thiourea and melamine.
本发明中，对原料中的B、P、S元素的联合控制，能够意外地进一步改善制得的材料的微观结构，改善P修饰杂化，改善其催化性能，特别是有助于改善产物的选择性。In the present invention, the combined control of the B, P, and S elements in the raw materials can unexpectedly further improve the microstructure of the prepared material, improve the P-modified hybridization, improve its catalytic performance, and especially help to improve the product selective.
作为优选，化合物原料中，S：B元素摩尔比为10～90:1；进一步优选为16～60：1；更进一步优选为20-60：1：最优选为28-60：1。Preferably, in the compound raw materials, the S:B element molar ratio is 10-90:1; more preferably 16-60:1; still more preferably 20-60:1; most preferably 28-60:1.
作为优选，化合物原料中，P：B元素摩尔比为0.5～2:1；进一步优选为1～2:1；更进一步优选为1～1.4:1。Preferably, in the compound raw materials, the molar ratio of P:B element is 0.5-2:1; more preferably 1-2:1; still more preferably 1-1.4:1.
作为优选，化合物原料中，N：B的元素摩尔比为10～200:1；进一步优选为30～130:1；更进一步优选为40～120:1。Preferably, in the compound raw materials, the molar ratio of N:B is 10-200:1; more preferably 30-130:1; still more preferably 40-120:1.
本发明中，可以将能够提供B、S、P和N元素的化合物在溶剂中进行重结晶反应。作为优选，所述的溶剂可以是水；In the present invention, the compound capable of providing B, S, P and N elements can be recrystallized in a solvent. As preferably, described solvent can be water;
优选地，重结晶的温度为30～90℃，进一步优选为40～90℃；更进一步优选为50～80℃。Preferably, the recrystallization temperature is 30-90°C, more preferably 40-90°C; even more preferably 50-80°C.
重结晶后可以进行常规的固液分离以及干燥处理，获得所述的产物。After recrystallization, conventional solid-liquid separation and drying can be performed to obtain the product.
本发明中，将重结晶获得的产物在含氨气氛下进行焙烧，研究发现得益于所述的S、P化合物的辅助，进一步配合升温速率以及温度，能够改善协同性，改善制得的材料的催化性能，特别是有助于改善制得的材料的选择性以及稳定性。In the present invention, the product obtained by recrystallization is roasted in an ammonia-containing atmosphere. It is found that benefiting from the assistance of the S and P compounds, further matching the heating rate and temperature can improve the synergy and improve the obtained material. Catalytic properties, especially help to improve the selectivity and stability of the prepared materials.
作为优选，升温速率为5～15℃/min；进一步优选为5～10℃/min；进一步优选为5～7.5℃/min。Preferably, the heating rate is 5-15°C/min; more preferably 5-10°C/min; further preferably 5-7.5°C/min.
作为优选，焙烧过程中，所述的含氨气气氛的氨气通入量为5～100mL/min；进一步优选为5～80mL/min；更进一步优选为40～60mL/min。Preferably, during the roasting process, the amount of ammonia gas introduced into the ammonia-containing atmosphere is 5-100 mL/min; more preferably 5-80 mL/min; still more preferably 40-60 mL/min.
作为优选，焙烧的温度为700℃～900℃；进一步优选为800℃～900℃。Preferably, the firing temperature is 700°C to 900°C; more preferably 800°C to 900°C.
本发明中，保温焙烧的时间大于或等于2h；优选为2～5h。In the present invention, the time for heat preservation and roasting is greater than or equal to 2 hours; preferably 2 to 5 hours.
本发明优选的制备方法，将硼源、氮源、磷源和硫源的原料水溶液进行重结晶，随后将重结晶产物经干燥、氨气气氛下焙烧得到。所述的磷源为羟基乙叉二磷酸一水合物、六氯三聚磷腈、磷酸二氢铵中的一种或几种复配；所述的硫源为硫脲、硫代乙硫脲、硫酸铵、硫代硫酸铵中的一种或几种；所述的硼源选自硼酸、氧化硼中的一种；所述的氮源选自尿素、单氰胺、二氰二胺、三聚氰胺中的一种或几种。所述的原料液重结晶的温度为40～90℃；所述重结晶产物的真空干燥温度为50～80℃，所述干燥时间为10～20h；所述氨气气氛焙烧时氨气通入量为5～100mL/min，升温速率为5～15℃/min，焙烧温度为700～900℃，焙烧时间为2～5h。The preferred preparation method of the present invention is obtained by recrystallizing the raw material aqueous solution of boron source, nitrogen source, phosphorus source and sulfur source, followed by drying and roasting the recrystallized product under ammonia atmosphere. The phosphorus source is one or more compounds of hydroxyethylidene diphosphate monohydrate, hexachlorotripolyphosphazene, and ammonium dihydrogen phosphate; the sulfur source is thiourea, thioethylthiourea , one or more of ammonium sulfate, ammonium thiosulfate; the boron source is selected from one of boric acid, boron oxide; the nitrogen source is selected from urea, cyanamide, dicyandiamine, One or several kinds of melamine. The recrystallization temperature of the raw material liquid is 40-90°C; the vacuum drying temperature of the recrystallized product is 50-80°C, and the drying time is 10-20h; The amount is 5-100mL/min, the heating rate is 5-15°C/min, the calcination temperature is 700-900°C, and the calcination time is 2-5h.
本发明中，还可将所述的催化剂负载在载体上。In the present invention, the catalyst can also be supported on a carrier.
本发明中，所述的载体可以是行业内公知的载体，且可以采用行业公知的负载方式进行负载制备。In the present invention, the carrier can be a carrier known in the industry, and can be prepared by using a known loading method in the industry.
优选地，所述的载体为三氧化二铝、二氧化硅中的至少一种或者含有二者之一成分的其他载体；Preferably, the carrier is at least one of aluminum oxide, silicon dioxide or other carrier containing one of the two components;
例如，所述的负载的步骤例如为：For example, the steps of the load are as follows:
将能提供B、P、S和N元素的化合物原料、甲醛以及能够转化为载体的前体原料在溶剂中进行重结晶，随后将重结晶产物进行所述的梯度焙烧，即得。The compound raw materials that can provide B, P, S and N elements, formaldehyde and precursor raw materials that can be converted into carriers are recrystallized in a solvent, and then the recrystallized products are subjected to the gradient roasting to obtain.
进一步具体的负载型催化剂(结构化催化剂)的制备过程例如为：The preparation process of further specific supported catalyst (structured catalyst) is for example:
采用甲醛等作为鼓泡介质的自成型的技术。具体为：称取所需质量的氮源物料，加入甲醛溶液，在30-90℃搅拌条件下冷凝回流至澄清。加入所需配比的硼源、磷源、硫源的原料，继续回流1-10小时。将样品转移到容器内，加入一定质量的硅酸钠、硅溶胶或铝溶胶的一种，搅拌均匀，于100-200℃恒温热处理12-36小时。将热处理后的样品取出破碎后过筛，取一定目数，置于管式炉内，通入5-80mL/min的氨气，以进行梯度焙烧，然后自然降温至室温，即得到负载型催化剂。Self-forming technology using formaldehyde etc. as the bubbling medium. Specifically: Weigh the required mass of nitrogen source material, add formaldehyde solution, condense and reflux under stirring at 30-90°C until clarified. Add the raw materials of boron source, phosphorus source and sulfur source in the required ratio, and continue to reflux for 1-10 hours. Transfer the sample to a container, add a certain quality of sodium silicate, silica sol or aluminum sol, stir evenly, and heat treat at 100-200°C for 12-36 hours. Take out the heat-treated sample, crush it, sieve it, take a certain mesh size, put it in a tube furnace, and pass it into 5-80mL/min ammonia gas to carry out gradient roasting, and then naturally cool down to room temperature to obtain a supported catalyst. .
作为同一发明构思的方案，本发明另一负载型催化剂的制备例如为：将载体 和合成的原料混合进行所述的重结晶以及焙烧处理，即得。As the solution of the same invention concept, the preparation of another supported catalyst of the present invention is, for example: mixing the carrier and the synthetic raw materials to carry out the recrystallization and roasting treatment to obtain final product.
本发明还包括所述的制备方法制得的催化剂。所述的催化剂，形态上可以为纳米、微米或毫米级的粉末状，也可以是更大尺寸的、采用自成型等手段进一步获得的结构化形态。The invention also includes the catalyst prepared by the preparation method. The catalyst can be in the form of nanometer, micron or millimeter-scale powder, or in a structured form with a larger size and further obtained by means of self-forming.
本发明创新地制备方法，其基于化合物S以及P参与BN的原位合成，并基于条件的联合控制，其能够有助于P的修饰以及修饰形态的控制，此外，还能够具有化合物S的作用，对材料的微观结构进行控制，能够意外地获得具有特殊化学以及物理结构的新材料。The innovative preparation method of the present invention is based on compound S and P participating in the in-situ synthesis of BN, and based on the combined control of conditions, it can contribute to the modification of P and the control of the modified form, in addition, it can also have the effect of compound S , to control the microstructure of materials, can unexpectedly obtain new materials with special chemical and physical structures.
本发明还公开了一种烷烃脱氢制烯的方法，将烷烃原料和所述制备方法制得的催化剂接触，进行脱氢反应，制得相应的烯烃产物。The invention also discloses a method for producing alkenes by dehydrogenating alkanes. The raw materials of alkanes are contacted with the catalyst prepared by the preparation method to carry out dehydrogenation reaction to prepare corresponding alkenes products.
本发明中，得益于所述的催化剂的使用，可实现烷烃的直接脱氢或者氧化脱氢，高效获得相应的烯烃，并具有良好的转化率、产物选择性及稳定性。In the present invention, thanks to the use of the catalyst, the direct dehydrogenation or oxidative dehydrogenation of alkanes can be realized, and the corresponding alkenes can be efficiently obtained, and have good conversion rate, product selectivity and stability.
作为优选，所述的烷烃原料为具有式1结构式的化合物：As preferably, the alkane feedstock is a compound of formula 1:
Figure PCTCN2021099761-appb-000001
Figure PCTCN2021099761-appb-000001
其中，R 1～R 4独自为H、C 1～C 10的烷基、C 3～C 10的环烷基或芳基；或者，R 1与R 4相互环合形成环基； Wherein, R 1 to R 4 are independently H, C 1 to C 10 alkyl, C 3 to C 10 cycloalkyl or aryl; or, R 1 and R 4 are ringed with each other to form a ring group;
所述的烷基、环烷基、环基或芳基上允许带有取代基，分别为取代烷基、取代环烷基、取代环基、取代芳基；其中，所述的取代基为C 1～C 6的烷基、C 1～C 6的烷氧基、卤素、苯基、硝基、三氟甲基中的至少一种取代基。 The alkyl group, cycloalkyl group, ring group or aryl group are allowed to have substituents, which are respectively substituted alkyl group, substituted cycloalkyl group, substituted ring group, and substituted aryl group; wherein, the described substituent group is C At least one substituent selected from 1 to C 6 alkyl, C 1 to C 6 alkoxy, halogen, phenyl, nitro, and trifluoromethyl.
本发明所述的烷基为直链或者支链烷基。所述的环烷基为三元～六元的单环、螺环或桥环。所述的芳基为苯环、五元杂环芳基、六元杂环芳基、或者由苯环、五元杂环芳基、六元杂环芳基中的两个及以上芳香环并合形成的稠环。The alkyl group described in the present invention is a straight chain or branched chain alkyl group. The cycloalkyl group is a three- to six-membered monocyclic ring, a spiro ring or a bridged ring. The aryl group is a benzene ring, a five-membered heterocyclic aryl group, a six-membered heterocyclic aryl group, or a combination of two or more aromatic rings in a benzene ring, a five-membered heterocyclic aryl group, or a six-membered heterocyclic aryl group. condensed rings formed.
此外，所述的R 1与R 4相互环合形成环基，所述的环基例如为五元或者六元的环。例如，环合后的烷烃原料结构例如为
Figure PCTCN2021099761-appb-000002
In addition, the R 1 and R 4 are ringed with each other to form a ring group, and the ring group is, for example, a five-membered or six-membered ring. For example, the alkane raw material structure after cyclization is, for example,
Figure PCTCN2021099761-appb-000002
本发明中，在所述的催化剂催化下，将式1直接或氧化脱氢，获得式2的烯烃产物
Figure PCTCN2021099761-appb-000003
In the present invention, under the catalysis of the catalyst, formula 1 is directly or oxidatively dehydrogenated to obtain the olefin product of formula 2
Figure PCTCN2021099761-appb-000003
优选地，所述的烷烃原料为具有式1-1结构的化合物；Preferably, the alkane raw material is a compound having the structure of formula 1-1;
Figure PCTCN2021099761-appb-000004
Figure PCTCN2021099761-appb-000004
式1-1中，R 1为H、C 1～C 6的烷基、苯基或者取代苯基；所述的取代苯基的苯环上含有C 1～C 6的烷基、C 1～C 6的烷氧基、卤素、苯基、硝基、三氟甲基中的至少一种取代基。 In formula 1-1, R 1 is H, C 1 -C 6 alkyl, phenyl or substituted phenyl; the phenyl ring of the substituted phenyl contains C 1 -C 6 alkyl, C 1 -C 6 At least one substituent of C6 alkoxy, halogen, phenyl, nitro, trifluoromethyl.
在本发明所述的催化剂催化下，可将式1-1直接催化制成相应的端烯烃产物(R 1-＝；式2-1)。 Under the catalysis of the catalyst described in the present invention, formula 1-1 can be directly catalyzed to produce the corresponding terminal olefin product (R 1 -=; formula 2-1).
作为优选，脱氢反应在无水条件下进行；或者在含弱氧气氛下进行。含弱氧气氛的氧含量例如不高于10vol.％；例如可以为1～5vol.％。Preferably, the dehydrogenation reaction is carried out under anhydrous conditions; or under an atmosphere containing weak oxygen. The oxygen content of the weak oxygen-containing atmosphere is, for example, not higher than 10 vol.%; for example, it can be 1-5 vol.%.
优选地，脱氢反应在有氧气氛或者无氧气氛下进行；Preferably, the dehydrogenation reaction is carried out under an oxygen atmosphere or an oxygen-free atmosphere;
优选地，脱氢反应的温度为500～700℃；优选为550～650℃；进一步优选为600～650℃。Preferably, the temperature of the dehydrogenation reaction is 500-700°C; preferably 550-650°C; more preferably 600-650°C.
本发明中，所述的脱氢反应可以基于现有的反应设备实现，例如，可以将其填充至反应器中，并进行气固相催化反应。In the present invention, the dehydrogenation reaction can be realized based on existing reaction equipment, for example, it can be filled into a reactor, and a gas-solid phase catalytic reaction can be performed.
原理：principle:
目前，对于非金属催化剂在烃类脱氢反应中的活性位，大多数研究者认为是存在于碳材料和氮化硼材料表面的C＝O基团或者B-OH基团。本发明所制备的催化剂，从后边的实施例、对比例，并利用XPS对表面基团、利用氮气物理吸附对孔结构的分析结果可知，N 3P-OH、N 2P＝O及N-B-O等基团均可以作为本反应的活性基团；而且，催化剂的微观结构对选择性和稳定性影响显著；通过在氮化硼原位合成阶段引入硫元素以及磷元素化合物，基于硫化合物、磷化合物以及条件的协同，能够改善P的修饰，并同时能够调控材料的微观结构，进而有助于改善制得的材料的催化性能。 At present, most researchers believe that the active sites of non-metallic catalysts in hydrocarbon dehydrogenation reactions are C=O groups or B-OH groups existing on the surface of carbon materials and boron nitride materials. The catalyst prepared by the present invention, from the following examples, comparative examples, and the analysis results of the surface groups by XPS and the pore structure by nitrogen physical adsorption, N 3 P-OH, N 2 P=O and NBO, etc. All groups can be used as active groups in this reaction; moreover, the microstructure of the catalyst has a significant impact on selectivity and stability; by introducing sulfur and phosphorus compounds during the in-situ synthesis of boron nitride, based on sulfur compounds and phosphorus compounds And the synergy of conditions can improve the modification of P, and at the same time can regulate the microstructure of the material, which in turn helps to improve the catalytic performance of the prepared material.
有益效果：Beneficial effect:
1、本发明创新在硫-磷化合物协同下进行氮化硼的原位合成，并进一步基于S、P物料形态、含量以及焙烧机制的协同下，能够改善P对BN的修饰，此外，还有助于调控微观结构，进而在保持良好转化率的同时，显著改善产物的选择性，改善积碳问题，改善催化剂的稳定性。本发明以典型的乙苯脱氢为例，单位催化 剂、单位时间内实现的苯乙烯生成量可达24.33mmol/(g·h)，苯乙烯选择性大于97％，稳定运行100小时以上。对于具有实际意义的工业化反应，具有重要的经济价值、环保价值和社会价值。1. The invention innovates in-situ synthesis of boron nitride under the synergy of sulfur-phosphorus compounds, and further based on the synergy of S, P material form, content and roasting mechanism, it can improve the modification of P to BN. In addition, there are It helps to regulate the microstructure, and then while maintaining a good conversion rate, it can significantly improve the selectivity of the product, improve the problem of carbon deposition, and improve the stability of the catalyst. The present invention takes typical ethylbenzene dehydrogenation as an example, the amount of styrene produced per unit catalyst and unit time can reach 24.33mmol/(g·h), the selectivity of styrene is greater than 97%, and the stable operation is more than 100 hours. For the industrialization reaction with practical significance, it has important economic value, environmental protection value and social value.
2、本发明进一步研究发现，传质状况对本反应催化剂的选择性和稳定性影响显著。通过控制所述催化剂制备过程的硫源种类、B/S比、以及焙烧温度、焙烧时间，以及结构化的做法，有助于调控催化剂的孔结构，进一步改善烷烃脱氢的选择性和稳定性。2. The further study of the present invention finds that the mass transfer condition has a significant impact on the selectivity and stability of the reaction catalyst. By controlling the type of sulfur source, B/S ratio, calcination temperature, calcination time, and structuring of the catalyst preparation process, it is helpful to regulate the pore structure of the catalyst and further improve the selectivity and stability of alkane dehydrogenation .
3、本发明进一步研究发现，N 3P-OH、N 2P＝O及N-B-O等基团均可以作为本反应的活性基团，从而为全新催化剂的设计提供理论指导。 3. The further study of the present invention found that groups such as N 3 P-OH, N 2 P=O and NBO can be used as active groups in this reaction, thus providing theoretical guidance for the design of new catalysts.
4、结构化催化剂具有更好的机械强度和成型性，可以满足不同条件的生产技术需求。4. The structured catalyst has better mechanical strength and formability, which can meet the production technology requirements of different conditions.
5、本发明所述的催化剂与目前工业中使用的含钾氧化铁催化剂相比，具有耐高温、抗积碳能力更强、制备工艺简单、无金属污染等优点，具有非常好的工业化应用前景。5. Compared with the potassium-containing iron oxide catalyst currently used in industry, the catalyst of the present invention has the advantages of high temperature resistance, stronger carbon deposition resistance, simple preparation process, and no metal pollution, and has a very good industrial application prospect .
附图说明Description of drawings
附图1：对比例1的催化剂的氮气吸附-脱附曲线Accompanying drawing 1: The nitrogen adsorption-desorption curve of the catalyst of comparative example 1
附图2：实施例1的催化剂的氮气吸附-脱附曲线Accompanying drawing 2: the nitrogen adsorption-desorption curve of the catalyst of embodiment 1
附图3：实施例1的催化剂的XPS图Accompanying drawing 3: the XPS figure of the catalyst of embodiment 1
附图4：实施例1的催化剂的TEM图Accompanying drawing 4: TEM figure of the catalyst of embodiment 1
附图5：实施例11的催化剂的SEM图Accompanying drawing 5: the SEM figure of the catalyst of embodiment 11
具体实施方式Detailed ways
以下结合实施例详述本发明。The present invention is described in detail below in conjunction with embodiment.
实施例1Example 1
称取一定量的硼酸(硼源，0.4g)、硫脲(硫源和氮源)、羟基乙叉二膦酸(磷源)，原料中，B：N：S：P的摩尔比为1：90：48：1.2)，加入40mL蒸馏水，搅拌溶解，然后将装有含前驱物溶液的烧杯在80℃油浴、300rpm搅拌条件下进行重结晶操作，至无明显水分，然后将得到的白色重结晶产物转入50℃真空干燥箱中进一步干燥12h。将干燥后的重结晶产物研磨成粉，装到刚玉方舟中，置 于管式炉内，通入60mL/min的氨气提供焙烧气氛，以5℃/min的升温速率自室温升温至800℃焙烧3h，然后在氨气保护下(氨气的流量为20mL/min)自然降温至室温，即得到催化剂，记：BNSP-硫脲/HEDP-48/1.2。制得的材料的氮气吸附-脱附曲线图2；XPS图见图3；TEM图见图4。Take a certain amount of boric acid (boron source, 0.4g), thiourea (sulfur source and nitrogen source), hydroxyethylidene diphosphonic acid (phosphorus source), in the raw material, the molar ratio of B:N:S:P is 1 :90:48:1.2), add 40mL of distilled water, stir to dissolve, and then recrystallize the beaker containing the precursor solution in an oil bath at 80°C and stirring at 300rpm until there is no obvious moisture, and then the obtained white The recrystallized product was transferred to a vacuum oven at 50°C for further drying for 12 hours. Grind the dried recrystallized product into powder, put it into a corundum ark, place it in a tube furnace, feed 60mL/min of ammonia gas to provide a roasting atmosphere, and raise the temperature from room temperature to 800°C at a heating rate of 5°C/min Roast for 3 hours, then cool down to room temperature naturally under the protection of ammonia gas (the flow rate of ammonia gas is 20mL/min) to obtain the catalyst, record: BNSP-thiourea/HEDP-48/1.2. The nitrogen adsorption-desorption curve of the prepared material is shown in Figure 2; the XPS diagram is shown in Figure 3; the TEM diagram is shown in Figure 4.
从图1、图2对比可以看出，制得的材料的氮气吸附-脱附曲线出现H3型回滞环，即存在狭缝孔结构，比表面积为101.13m 2/g，该材料的比表面积比前期工作中BNP-1.2(对比例1)的比表面积(140～260m 2/g)小，结合孔径分析，材料的平均孔径为13.39nm，远大于BNP-1.2的孔径(3nm),因此比表面积低于BNP-1.2。此外，图3的XPS测试发现，S的原子百分比低于仪器的检测线，即S很难进入到BN骨架或表面，因此可推断S源的作用主要是影响了材料热处理过程中催化剂微观结构的形成。 From the comparison of Figure 1 and Figure 2, it can be seen that the nitrogen adsorption-desorption curve of the prepared material has an H3 hysteresis loop, that is, there is a slit pore structure, and the specific surface area is 101.13m 2 /g. Compared with the specific surface area (140-260m 2 /g) of BNP-1.2 (comparative example 1) in the previous work, combined with the pore size analysis, the average pore size of the material is 13.39nm, which is much larger than the pore size of BNP-1.2 (3nm), so it is better than The surface area is lower than BNP-1.2. In addition, the XPS test in Figure 3 found that the atomic percentage of S is lower than the detection line of the instrument, that is, it is difficult for S to enter the BN framework or surface, so it can be inferred that the role of the S source mainly affects the microstructure of the catalyst during the heat treatment of the material. form.
催化剂性能的测试方法为：将催化剂50mg，加入2mL粒度为40～60目的石英砂稀释，装入Φ8mm的固定床石英反应管中，催化剂床层两端以少量石英棉封堵。通入20mL/min的氮气提供惰性气体气氛。氮气保护下，以4℃/min的速率升温到600℃，稳定30min对催化剂进行预活化，然后以20mL/min的流速通入乙苯体积分数为2.8％的混合原料气，进行连续反应。反应产物用5℃的乙醇收集，通过岛津GC-2010Plus气相色谱仪分析其组成，色谱柱型号为RTX-5，检测器为FID。初始乙苯转化率77.43％，苯乙烯选择性97.25％，对应的单位催化剂上单位时间内实现的苯乙烯生成量为22.72mmol/(g·h)，可以稳定40小时以上。The test method of the catalyst performance is: 50mg of the catalyst is added to 2mL of quartz sand with a particle size of 40-60 mesh to dilute, put into a Φ8mm fixed-bed quartz reaction tube, and both ends of the catalyst bed are blocked with a small amount of quartz wool. Inject 20 mL/min of nitrogen to provide an inert gas atmosphere. Under the protection of nitrogen, the temperature was raised to 600°C at a rate of 4°C/min, and the catalyst was stabilized for 30 minutes to preactivate the catalyst, and then a mixed raw material gas with a volume fraction of 2.8% ethylbenzene was introduced at a flow rate of 20mL/min for continuous reaction. The reaction product was collected with ethanol at 5°C, and its composition was analyzed by Shimadzu GC-2010Plus gas chromatograph, the column model was RTX-5, and the detector was FID. The initial conversion rate of ethylbenzene is 77.43%, the selectivity of styrene is 97.25%, and the corresponding amount of styrene generated per unit time on the catalyst is 22.72mmol/(g·h), which can be stable for more than 40 hours.
实施例2Example 2
与实施例1相比，区别仅在于，改变了硫源的成分，分别采用硫代硫酸铵、硫酸铵进行研究，其中，以硫代硫酸铵作硫源时，以尿素做补充氮源，以控制B:N的比例保持不变，其他参数以及操作均同实施例1。Compared with Example 1, the only difference is that the composition of the sulfur source was changed, and ammonium thiosulfate and ammonium sulfate were used for research respectively. Wherein, when ammonium thiosulfate was used as the sulfur source, urea was used as a supplementary nitrogen source, and urea was used as a supplementary nitrogen source. The ratio of control B:N remains unchanged, and other parameters and operations are the same as in Example 1.
采用实施例1中的催化剂性能测试方法，测得催化剂的性能见表1所示：Adopt the catalyst performance testing method among the embodiment 1, record the performance of catalyst as shown in table 1:
表1：Table 1:
Figure PCTCN2021099761-appb-000005
Figure PCTCN2021099761-appb-000005
Figure PCTCN2021099761-appb-000006
Figure PCTCN2021099761-appb-000006
实施例3Example 3
与实施例1相比，区别仅在于，改变硫源的摩尔比，分别为B:S的摩尔比分别为1:16、1:20、1:24、1:28，并以尿素做补充氮源，以保持B：N不变，另外，B:S的摩尔比为1:60案例中，未额外添加尿素作为氮源；其他参数以及操作均同实施例1。Compared with Example 1, the only difference is that the molar ratio of the sulfur source is changed, respectively, the molar ratios of B:S are 1:16, 1:20, 1:24, 1:28, and urea is used to supplement nitrogen Source, to keep B:N unchanged, in addition, the molar ratio of B:S is 1:60 in the case, no additional urea is added as a nitrogen source; other parameters and operations are the same as in Example 1.
采用实施例1中的催化剂性能测试方法，测得催化剂的性能见表2所示：Adopt the catalyst performance test method in embodiment 1, record the performance of catalyst as shown in table 2:
表2Table 2
Figure PCTCN2021099761-appb-000007
Figure PCTCN2021099761-appb-000007
a:未额外添加尿素。a: No additional urea was added.
实施例4Example 4
与实施例1相比，区别仅在于，改变了磷源的成分，分别采用磷酸二氢铵、六氯三聚磷腈进行研究，其他参数以及操作均同实施例1。Compared with Example 1, the only difference is that the composition of the phosphorus source was changed, and ammonium dihydrogen phosphate and hexachlorotrimeric phosphazene were used for research, and other parameters and operations were the same as in Example 1.
采用实施例1中的催化剂性能测试方法，测得催化剂的性能见表3所示：Adopt the catalyst performance testing method among the embodiment 1, record the performance of catalyst as shown in table 3:
表3table 3
Figure PCTCN2021099761-appb-000008
Figure PCTCN2021099761-appb-000008
Figure PCTCN2021099761-appb-000009
Figure PCTCN2021099761-appb-000009
实施例5Example 5
与实施例1相比，区别仅在于，改变磷源的摩尔比，分别为B:P的摩尔比分别为1:1.0、1:1.4，其他参数以及操作均同实施例1。Compared with Example 1, the only difference is that the molar ratio of the phosphorus source is changed, the molar ratios of B:P are respectively 1:1.0 and 1:1.4, and other parameters and operations are the same as in Example 1.
采用实施例1中的催化剂性能测试方法，测得催化剂的性能见表4所示：Adopt the catalyst performance testing method among the embodiment 1, record the performance of catalyst as shown in table 4:
表4Table 4
Figure PCTCN2021099761-appb-000010
Figure PCTCN2021099761-appb-000010
由实施例5以及我们的前期工作可以看出，B：P摩尔比的大小决定了制备得到的材料中磷元素原子百分比以及活性位点N 2P＝O和N 3P-OH的相对比例。当B:P≤1:1.4时，制备得到的材料中磷元素原子百分比增加，N 2P＝O和N 3P-OH的相对比例逐渐降低。结合DFT理论计算，N 2P＝O促进了乙苯中C-H键的断裂，N 3P-OH降低了断裂后产生的H*结合解吸的能垒，二者协同作用下实现乙苯直接脱氢生成苯乙烯的反应。当B:P＞1:1.4时，由于HEDP的使用在引入P的同时会引入大量的C和O，导致所制备的材料中磷元素的原子百分比降低，所以催化性能较差。综合考虑，优选的B：P摩尔比为1：0.9～1.4。 It can be seen from Example 5 and our previous work that the molar ratio of B:P determines the atomic percentage of phosphorus in the prepared material and the relative ratio of active sites N 2 P=O and N 3 P-OH. When B:P≤1:1.4, the atomic percentage of phosphorus element in the prepared material increases, and the relative ratio of N 2 P=O and N 3 P-OH decreases gradually. Combined with DFT theoretical calculations, N 2 P=O promotes the breaking of the CH bond in ethylbenzene, and N 3 P-OH reduces the energy barrier for H* binding and desorption after the breaking, and the direct dehydrogenation of ethylbenzene is realized under the synergistic effect of the two The reaction to form styrene. When B:P>1:1.4, since the use of HEDP introduces a large amount of C and O while introducing P, the atomic percentage of phosphorus element in the prepared material decreases, so the catalytic performance is poor. Considering comprehensively, the preferred B:P molar ratio is 1:0.9-1.4.
实施例6Example 6
与实施例1相比，改变升温速率(升温至焙烧温度的速率)，分别为7.5℃/min、10℃/min，其他参数以及操作均同实施例1。Compared with Example 1, the heating rate (the rate of heating up to the calcination temperature) was changed to 7.5°C/min and 10°C/min respectively, and other parameters and operations were the same as in Example 1.
采用实施例1中的催化剂性能测试方法，测得催化剂的性能见表5所示：Adopt the catalyst performance test method in embodiment 1, record the performance of catalyst as shown in table 5:
表5table 5
Figure PCTCN2021099761-appb-000011
Figure PCTCN2021099761-appb-000011
Figure PCTCN2021099761-appb-000012
Figure PCTCN2021099761-appb-000012
由实施例1和6可以看出，在大于或等于5℃/min的升温速率下特别是优选的5～7.5℃/min可以获得性能优异的催化性能。It can be seen from Examples 1 and 6 that excellent catalytic performance can be obtained at a heating rate greater than or equal to 5°C/min, especially preferably 5-7.5°C/min.
实施例7Example 7
与实施例1相比，改变焙烧的温度，分别为600℃、700℃、900℃，其他参数以及操作均同实施例1。Compared with Example 1, the firing temperature was changed to 600°C, 700°C, and 900°C respectively, and other parameters and operations were the same as in Example 1.
采用实施例1中的催化剂性能测试方法，测得催化剂的性能见表6所示：Adopt the catalyst performance testing method among the embodiment 1, record the performance of catalyst as shown in table 6:
表6Table 6
Figure PCTCN2021099761-appb-000013
Figure PCTCN2021099761-appb-000013
研究发现，在大于或等于600℃的温度，特别是优选的800～900℃，可以获得良好的催化性能。Research has found that good catalytic performance can be obtained at a temperature greater than or equal to 600°C, especially preferably 800-900°C.
实施例8Example 8
和实施例2中硫代硫酸铵作为硫源相比，区别仅在于，N源的补充分别为单氰胺、二氰二胺，其他参数以及操作均同实施例1。Compared with ammonium thiosulfate as the sulfur source in Example 2, the only difference is that the N sources are supplemented with cyanamide and dicyandiamide respectively, and other parameters and operations are the same as in Example 1.
采用实施例1中的催化剂性能测试方法，测得催化剂的性能见表7所示：Adopt the catalyst performance testing method among the embodiment 1, record the performance of catalyst as shown in table 7:
表7Table 7
Figure PCTCN2021099761-appb-000014
Figure PCTCN2021099761-appb-000014
Figure PCTCN2021099761-appb-000015
Figure PCTCN2021099761-appb-000015
实施例9Example 9
与实施例1相比，同时改变氮气流量、升温速率和焙烧的温度(80mL/min，10℃/min，900℃)。采用实施例1中的催化剂性能测试方法，测得催化剂的性能为：初始乙苯转化率63.09％，苯乙烯选择性97.33％，对应的单位催化剂上单位时间内实现的苯乙烯生成量为18.53mmol/(g·h)，可以稳定40小时以上。Compared with Example 1, the nitrogen flow rate, heating rate and roasting temperature (80mL/min, 10°C/min, 900°C) were changed at the same time. Using the catalyst performance testing method in Example 1, the performance of the catalyst is measured as follows: the initial ethylbenzene conversion rate is 63.09%, the styrene selectivity is 97.33%, and the styrene production amount realized per unit time on the corresponding unit catalyst is 18.53mmol /(g·h), can be stable for more than 40 hours.
实施例10Example 10
称取市售二腈二胺8.4g，加入10ml市售37％浓度甲醛溶液，置于50ml三颈烧瓶内，在85℃油浴、400rpm条件下冷凝回流至澄清后，在同样条件下继续冷凝回流1h。Weigh 8.4g of commercially available dinitrile diamine, add 10ml of commercially available 37% formaldehyde solution, place in a 50ml three-necked flask, reflux in an oil bath at 85°C and 400rpm until clarification, and continue to condense under the same conditions Reflux for 1h.
称取一定量市售硼酸(0.4g)，硫脲，羟基乙叉二膦酸(原料中，B：N：S：P的摩尔比为1：90：48：1.2)，加入三颈烧瓶中，继续在85℃油浴、400rpm条件下冷凝回流至澄清后，在同样条件下继续冷凝回流1h。Weigh a certain amount of commercially available boric acid (0.4g), thiourea, and hydroxyethylidene diphosphonic acid (in the raw material, the molar ratio of B:N:S:P is 1:90:48:1.2), and add them to a three-necked flask , continue to condense and reflux under the conditions of 85°C oil bath and 400rpm until clarification, and continue to condense and reflux for 1h under the same conditions.
将样品转移到试管内，称取市售硅酸钠1.5g加入试管，搅拌均匀，盖上有小孔的塞子，放入180℃烘箱中恒温热处理12h。Transfer the sample to a test tube, weigh 1.5 g of commercially available sodium silicate into the test tube, stir evenly, cover with a stopper with a small hole, and place it in an oven at 180°C for constant temperature heat treatment for 12 hours.
将热处理后的样品取出砸碎后过筛，取20至40目样品，装到刚玉方舟中，置于管式炉内，通入60mL/min的氨气提供焙烧气氛，以5℃/min的升温速率自室温升温至800℃焙烧3h，然后在氨气保护下自然降温至室温，即得到自成型的硫修饰的磷掺杂氮化硼催化剂，记：BNSP-硫脲/HEDP-48/1.2-自成型。Take out the heat-treated sample, crush it, and sieve it. Take a 20-40 mesh sample, put it in a corundum ark, place it in a tube furnace, and feed 60mL/min of ammonia gas to provide a roasting atmosphere. The heating rate is raised from room temperature to 800°C and roasted for 3 hours, and then naturally cooled to room temperature under the protection of ammonia gas to obtain a self-formed sulfur-modified phosphorus-doped boron nitride catalyst, record: BNSP-thiourea/HEDP-48/1.2 -Self-forming.
加入2mL粒度为40～60目的BNSP-硫脲/HEDP-48/1.2-自成型，采用实施例1中的催化剂性能测试方法，测得催化剂的性能为：初始乙苯转化率78.31％，苯乙烯选择性97.39％，对应的单位催化剂上单位时间内实现的苯乙烯生成量为23.01mmol/(g·h)，可以稳定100小时以上。Add 2 mL of BNSP-thiourea/HEDP-48/1.2-self-molding with a particle size of 40 to 60 meshes, adopt the catalyst performance test method in Example 1, and measure the performance of the catalyst: the initial ethylbenzene conversion rate is 78.31%, styrene The selectivity is 97.39%, and the corresponding amount of styrene produced per unit time on the catalyst is 23.01 mmol/(g·h), which can be stable for more than 100 hours.
实施例11(与实施例1相比，负载法制备的结构化催化剂)Embodiment 11 (compared with embodiment 1, the structured catalyst prepared by loading method)
与实施例1相比，将20-40目的活性氧化铝颗粒加入到硼酸、硫脲、羟基乙叉二膦酸一水合物的混合溶液中，其他步骤不变。催化剂记为：BNP@氧化铝/HEDP-48/1.2。采用实施例1中的催化剂性能测试方法，测得催化剂的性能为： 初始乙苯转化率82.50％，苯乙烯选择性97.72％，对应的单位催化剂上单位时间内实现的苯乙烯生成量为24.33mmol/(g·h)，可以稳定100小时以上。Compared with Example 1, 20-40 mesh activated alumina particles were added to the mixed solution of boric acid, thiourea, and hydroxyethylidene diphosphonic acid monohydrate, and other steps remained unchanged. The catalyst is recorded as: BNP@alumina/HEDP-48/1.2. Using the catalyst performance test method in Example 1, the performance of the catalyst is measured as follows: the initial ethylbenzene conversion rate is 82.50%, the styrene selectivity is 97.72%, and the styrene production amount realized per unit time on the corresponding unit catalyst is 24.33mmol /(g·h), can be stable for more than 100 hours.
实施例12(氧化脱氢)Embodiment 12 (oxidative dehydrogenation)
将实施例1的催化剂，应用于弱氧氛围下的氧化脱氢。与实施例1相比，催化剂的性能测试方法中，20ml/min的氮气改为含有氧气3％(体积百分数)的氮氧混合气，测得催化剂的性能为：初始乙苯转化率78.35％，苯乙烯选择性94.60％，对应的单位催化剂上单位时间内实现的苯乙烯生成量为22.36mmol/(g·h)，可以稳定100小时以上。The catalyst of Example 1 was applied to oxidative dehydrogenation under weak oxygen atmosphere. Compared with embodiment 1, in the performance test method of catalyst, the nitrogen of 20ml/min is changed into the nitrogen-oxygen mixture containing oxygen 3% (volume percent), and the performance of recording catalyst is: initial ethylbenzene conversion rate 78.35%, The selectivity of styrene is 94.60%, and the corresponding amount of styrene produced per unit time on the catalyst is 22.36mmol/(g·h), which can be stable for more than 100 hours.
实施例13Example 13
和实施例1相比，区别仅在于，脱氢反应过程的温度分别为550℃、575℃、625℃，其他参数以及操作均同实施例1。Compared with Example 1, the only difference is that the temperatures of the dehydrogenation reaction process are 550°C, 575°C, and 625°C respectively, and other parameters and operations are the same as in Example 1.
采用实施例1中的催化剂性能测试方法，测得催化剂的性能见表7所示：Adopt the catalyst performance testing method among the embodiment 1, record the performance of catalyst as shown in table 7:
表7Table 7
Figure PCTCN2021099761-appb-000016
Figure PCTCN2021099761-appb-000016
对比例1Comparative example 1
和实施例1相比，主要仅在于，未添加硫源，氮源由尿素代替，具体步骤同申请号为201910739798.4的实施例1；催化剂记为BNP 1.2。Compared with Example 1, the main reason is that no sulfur source is added, and the nitrogen source is replaced by urea. The specific steps are the same as Example 1 with application number 201910739798.4; the catalyst is recorded as BNP 1.2.
该对比例的催化效果为：初始乙苯转化率62.42％，苯乙烯选择性93.54％，对应的单位催化剂上单位时间内实现的乙苯转化量为17.62mmol/(g·h)，可以稳定20小时以上。其效果显著差于实施例1，且产物的选择性差于本发明实施方案。The catalytic effect of this comparative example is: the initial conversion rate of ethylbenzene is 62.42%, and the selectivity of styrene is 93.54%. hours or more. Its effect is significantly worse than that of Example 1, and the selectivity of the product is worse than that of the embodiment of the present invention.
对比例2Comparative example 2
与实施例1相比，区别仅在于，采用单质硫(升华硫，添加摩尔量同实施例1；N源由尿素提供，且N源的摩尔量同实施例1)，其他条件均同实施例1，催化剂记为：BNSP-升华硫/HEDP-48/1.2。采用实施例1中的催化剂性能测试方法，测得催化剂的性能为：初始乙苯转化率22.36％，苯乙烯选择性93.71％。对应的单位催化剂上单位时间内实现的苯乙烯生成量为6.32mmol/(g·h)。Compared with Example 1, the only difference is that elemental sulfur is used (sublimed sulfur, the added molar weight is the same as that of Example 1; the N source is provided by urea, and the molar weight of the N source is the same as that of Example 1), and other conditions are the same as in Example 1. 1. The catalyst is recorded as: BNSP-sublimed sulfur/HEDP-48/1.2. Using the catalyst performance test method in Example 1, the performance of the catalyst was measured as follows: the initial ethylbenzene conversion rate was 22.36%, and the styrene selectivity was 93.71%. The corresponding amount of styrene produced per unit time on the catalyst is 6.32 mmol/(g·h).
对比例3Comparative example 3
与实施例1相比，区别仅在于，不添加磷源。催化剂记为：BNS-48。采用实施例1中的催化剂性能测试方法，测得催化剂的性能为：29.73％，苯乙烯选择性97.68％。对应的单位催化剂上单位时间内实现的苯乙烯生成量为8.76mmol/(g·h)，可以稳定20小时以上。其效果显著差于实施例1，主要是产物的转化率差于本发明实施方案。Compared with Example 1, the only difference is that no phosphorus source is added. The catalyst is recorded as: BNS-48. Using the catalyst performance test method in Example 1, the performance of the catalyst was measured as: 29.73%, and the selectivity to styrene was 97.68%. The corresponding amount of styrene produced per unit time on the unit catalyst is 8.76mmol/(g·h), which can be stable for more than 20 hours. Its effect is significantly worse than that of Example 1, mainly because the conversion rate of the product is worse than that of the embodiment of the present invention.
对比例4Comparative example 4
与实施例1相比，区别仅在于，磷源为磷单质(红磷，添加摩尔量同实施例1)。催化剂记为：BNSP-硫脲/P-48-1.2。采用实施例1中的催化剂性能测试方法，测得催化剂的性能为：初始乙苯转化率20.04％，苯乙烯选择性90.68％。对应的单位催化剂上单位时间内实现的苯乙烯生成量为5.48mmol/(g·h)。Compared with Example 1, the only difference is that the phosphorus source is phosphorus simple substance (red phosphorus, the added molar amount is the same as that of Example 1). The catalyst is recorded as: BNSP-thiourea/P-48-1.2. Using the catalyst performance test method in Example 1, the performance of the catalyst was measured as follows: the initial ethylbenzene conversion rate was 20.04%, and the styrene selectivity was 90.68%. The corresponding amount of styrene produced per unit time on the catalyst is 5.48 mmol/(g·h).
对比例5Comparative example 5
与实施例1、实施例5相比，区别仅在于，硼元素与磷元素的摩尔比为1：0.2)，催化剂记为：BNSP-硫脲/HEDP-48/0.2。采用实施例1中的催化剂性能测试方法，测得催化剂的性能为：初始乙苯转化率28.42％，苯乙烯选择性95.31％，对应的单位催化剂上单位时间内实现的苯乙烯生成量为8.17mmol/(g·h)。Compared with Example 1 and Example 5, the only difference is that the molar ratio of boron element to phosphorus element is 1:0.2), and the catalyst is recorded as: BNSP-thiourea/HEDP-48/0.2. Using the catalyst performance testing method in Example 1, the performance of the catalyst is measured as follows: the initial conversion rate of ethylbenzene is 28.42%, the selectivity of styrene is 95.31%, and the amount of styrene generated per unit time on the corresponding unit catalyst is 8.17mmol /(g·h).
对比例6Comparative example 6
与实施例1、实施例6相比，区别仅在于，升温速率为1℃/min。采用实施例1中的催化剂性能测试方法，测得催化剂的性能为：初始乙苯转化率46.59％，苯乙烯选择性92.42％。对应的单位催化剂上单位时间内实现的苯乙烯生成量为 12.99mmol/(g·h)，可以稳定20小时以上。Compared with Example 1 and Example 6, the only difference is that the heating rate is 1° C./min. Using the catalyst performance testing method in Example 1, the performance of the catalyst was measured as follows: the initial ethylbenzene conversion rate was 46.59%, and the styrene selectivity was 92.42%. The amount of styrene produced per unit time on the corresponding unit catalyst is 12.99mmol/(g h), which can be stable for more than 20 hours.
对比例7Comparative example 7
与实施例1、实施例7相比，区别仅在于，焙烧温度为1100℃。采用实施例1中的催化剂性能测试方法，测得催化剂的性能为：初始乙苯转化率50.33％，苯乙烯选择性83.03％。对应的单位催化剂上单位时间内实现的苯乙烯生成量为12.61mmol/(g·h)，可以稳定20小时以上。Compared with Example 1 and Example 7, the only difference is that the firing temperature is 1100°C. Using the catalyst performance testing method in Example 1, the performance of the catalyst was measured as follows: the initial ethylbenzene conversion rate was 50.33%, and the styrene selectivity was 83.03%. The corresponding amount of styrene produced per unit time on the unit catalyst is 12.61 mmol/(g·h), which can be stabilized for more than 20 hours.
对比例8Comparative example 8
探讨BN和硫源和P源物理混合：Explore the physical mixing of BN and sulfur and P sources:
与实施例1相比，区别主要在于，先不加磷源和硫源，直接合成BN(合成方式同实施例1，例如，采用B在氨气气氛下进行烧结)；随后再将BN和硫源(硫脲)和P源按比例混合，进一步在氮气保护气氛下热处理。采用实施例1中的催化剂性能测试方法，测得催化剂的性能为：初始乙苯转化率18.51％，苯乙烯选择性85.47％。对应的单位催化剂上单位时间内实现的苯乙烯生成量为4.77mmol/(g·h)，可以稳定20小时以上。Compared with Example 1, the difference is mainly that BN is directly synthesized without adding a phosphorus source and a sulfur source (the synthesis method is the same as in Example 1, for example, using B to sinter under an ammonia atmosphere); then BN and sulfur The source (thiourea) and the P source were mixed in proportion, and further heat-treated under a nitrogen protective atmosphere. Using the catalyst performance testing method in Example 1, the performance of the catalyst was measured as follows: the initial ethylbenzene conversion rate was 18.51%, and the styrene selectivity was 85.47%. The corresponding amount of styrene produced per unit time on the unit catalyst is 4.77mmol/(g·h), which can be stabilized for more than 20 hours.
对比例9(空白载体石英砂)Comparative example 9 (blank carrier quartz sand)
量取2mL粒度为40～60目的石英砂，采用实施例1中的催化剂性能测试方法，测得催化剂的性能为：初始乙苯转化率8.82％，苯乙烯选择性58.33％，对应的单位催化剂上单位时间内实现的苯乙烯生成量为1.55mmol/(g·h)。Measure 2mL of quartz sand with a particle size of 40 to 60 meshes, and use the catalyst performance test method in Example 1 to measure the performance of the catalyst: the initial ethylbenzene conversion rate is 8.82%, and the styrene selectivity is 58.33%. The amount of styrene produced per unit time was 1.55 mmol/(g·h).
对比例10(空白载体硅酸钠)Comparative example 10 (blank carrier sodium silicate)
量取2mL硅酸钠，采用实施例1中的催化剂性能测试方法，测得催化剂的性能为：初始乙苯转化率7.80％，苯乙烯选择性62.45％，对应的单位催化剂上单位时间内实现的苯乙烯生成量为1.47mmol/(g·h)。Measure 2mL of sodium silicate, adopt the catalyst performance testing method among the embodiment 1, record the performance of catalyst as: initial ethylbenzene conversion rate 7.80%, styrene selectivity 62.45%, realize on the corresponding unit catalyst unit time The amount of styrene produced was 1.47 mmol/(g·h).
分析：analyze:
从实施例、对比例的结果来看，(1)硫元素的掺杂，可以显著提高磷氮硼催化剂对苯乙烯的选择性。(2)硫源、磷源的共同加入，是获得高性能催化剂 的关键之一。(3)硫源类型、磷源类型，及添加量，是获得高性能催化剂的关键之二。(4)升温制度是获得高性能催化剂的关键之三。从附图可以看出，催化剂是明显的多孔材料。硫元素主要影响着催化剂合成过程中孔结构的形成。使得催化剂孔结构更加合理，动力学上有利于中间体的传递和转化，避免副反应的发生。From the results of Examples and Comparative Examples, (1) the doping of sulfur element can significantly improve the selectivity of the phosphorus nitrogen boron catalyst to styrene. (2) The joint addition of sulfur source and phosphorus source is one of the keys to obtain high-performance catalysts. (3) The type of sulfur source, the type of phosphorus source, and the amount added are the second key to obtaining a high-performance catalyst. (4) The heating system is the third key to obtain high-performance catalysts. As can be seen from the figures, the catalyst is a distinctly porous material. Sulfur element mainly affects the formation of pore structure in the catalyst synthesis process. The pore structure of the catalyst is more reasonable, the kinetics is beneficial to the transfer and conversion of intermediates, and the occurrence of side reactions is avoided.

Claims (10)

  1. 一种烷烃脱氢制烯烃催化剂的制备方法，其特征在于，将能提供B、P、S、N元素的化合物原料在溶剂中进行重结晶，随后将重结晶产物在含氨气气氛内、在大于或等于5℃/min的升温速率下升温至700～1000℃，并进行保温焙烧，制得所述的催化剂；A preparation method of a catalyst for alkane dehydrogenation to olefins, characterized in that the compound raw materials that can provide B, P, S, and N elements are recrystallized in a solvent, and then the recrystallized product is placed in an ammonia-containing atmosphere. heating up to 700-1000°C at a heating rate greater than or equal to 5°C/min, and performing heat preservation and roasting to obtain the catalyst;
    所述的化合物原料中，S：B元素摩尔比为大于或等于10；优选为10～90:1；进一步优选为16～60：1；更进一步优选为20-60：1：最优选为28-60：1；In the compound raw materials, the S:B element molar ratio is greater than or equal to 10; preferably 10-90:1; more preferably 16-60:1; still more preferably 20-60:1; most preferably 28 -60:1;
    P：B元素摩尔比为大于或等于0.5；优选为0.5～2:1；进一步优选为1～2:1；更进一步优选为1～1.4:1；The molar ratio of P:B element is greater than or equal to 0.5; preferably 0.5-2:1; more preferably 1-2:1; still more preferably 1-1.4:1;
    N：B的元素摩尔比大于或等于10；优选为10～200:1；进一步优选为30～130:1；更进一步优选为40～120:1。The element molar ratio of N:B is greater than or equal to 10; preferably 10-200:1; more preferably 30-130:1; still more preferably 40-120:1.
  2. 如权利要求1所述的烷烃脱氢制烯烃催化剂的制备方法，其特征在于，所述的化合物原料包括硼源、磷源、硫源和氮源，其中，所述的硼源为能够提供硼元素的硼化合物；The preparation method of alkane dehydrogenation olefin catalyst as claimed in claim 1, is characterized in that, described compound raw material comprises boron source, phosphorus source, sulfur source and nitrogen source, and wherein, described boron source can provide boron boron compounds of the element;
    所述的磷源为能够提供磷元素的磷化合物；The phosphorus source is a phosphorus compound that can provide phosphorus;
    所述的硫源为能够提供硫元素的硫化合物；The sulfur source is a sulfur compound capable of providing elemental sulfur;
    所述的氮源为能够提供氮元素的氮化合物；Described nitrogen source is the nitrogen compound that can provide nitrogen element;
    优选地，所述的硫源为硫脲、硫代乙硫脲、硫代硫酸铵和硫酸铵中的一种或几种；Preferably, the sulfur source is one or more of thiourea, thioethylthiourea, ammonium thiosulfate and ammonium sulfate;
    优选地，所述的磷源为羟基乙叉二磷酸、六氯三聚磷腈、磷酸二氢铵中的至少一种；Preferably, the phosphorus source is at least one of hydroxyethylidene diphosphoric acid, hexachlorotrimeric phosphazene, and ammonium dihydrogen phosphate;
    优选地，所述的氮源为尿素、单氰胺、二氰胺、硫脲和三聚氰胺中的至少一种；Preferably, the nitrogen source is at least one of urea, cyanamide, dicyandiamide, thiourea and melamine;
    优选地，所述的硼源选自硼酸和氧化硼中的至少一种。Preferably, the boron source is selected from at least one of boric acid and boron oxide.
  3. 如权利要求1所述的烷烃脱氢制烯烃催化剂的制备方法，其特征在于，所述的溶剂为水；the preparation method of alkane dehydrogenation olefin catalyst as claimed in claim 1, is characterized in that, described solvent is water;
    优选地，重结晶的温度为30～90℃，进一步优选为40～90℃。Preferably, the recrystallization temperature is 30-90°C, more preferably 40-90°C.
  4. 如权利要求1所述的烷烃脱氢制烯烃催化剂的制备方法，其特征在于， 焙烧过程中，所述的含氨气气氛的氨气通入量为5-100mL/min；优选为40～60mL/min。The preparation method of the catalyst for alkane dehydrogenation to olefins as claimed in claim 1, characterized in that, during the roasting process, the amount of ammonia gas introduced into the ammonia-containing atmosphere is 5-100mL/min; preferably 40-60mL /min.
  5. 如权利要求1所述的烷烃脱氢制烯烃催化剂的制备方法，其特征在于，焙烧的温度为700℃～900℃；进一步优选为800℃～900℃；The preparation method of the catalyst for alkane dehydrogenation to olefins as claimed in claim 1, characterized in that the roasting temperature is 700°C-900°C; more preferably 800°C-900°C;
    优选地，升温速率为5～15℃/min；进一步优选为5～10℃/min；进一步优选为5～7.5℃/min。Preferably, the heating rate is 5-15°C/min; more preferably 5-10°C/min; further preferably 5-7.5°C/min.
  6. 如权利要求1～5任一项所述的烷烃脱氢制烯烃催化剂的制备方法，其特征在于，可以将所述的催化剂负载在载体上；The preparation method of the catalyst for alkane dehydrogenation to olefins according to any one of claims 1 to 5, characterized in that the catalyst can be loaded on a carrier;
    优选地，所述的载体为三氧化二铝、二氧化硅中的至少一种或者含有二者之一成分的其他载体；Preferably, the carrier is at least one of aluminum oxide, silicon dioxide or other carrier containing one of the two components;
    优选地，负载的步骤为：Preferably, the steps of loading are:
    将能提供B、P、S和N元素的化合物原料、甲醛以及能够转化为载体的前体原料在溶剂中进行重结晶，随后将重结晶产物进行所述的焙烧，即得；Recrystallize the compound raw materials that can provide B, P, S and N elements, formaldehyde, and precursor raw materials that can be converted into carriers in a solvent, and then perform the above-mentioned roasting on the recrystallized products to obtain;
    或者，将载体和合成的原料混合进行所述的重结晶以及焙烧处理，即得。Alternatively, it can be obtained by mixing the carrier and the synthetic raw materials and performing the recrystallization and roasting treatment.
  7. 一种烷烃脱氢制烯烃催化剂，其特征在于，由权利要求1～6任一项制备方法制得。A catalyst for alkane dehydrogenation to olefins, characterized in that it is prepared by any one of the preparation methods of claims 1-6.
  8. 一种烷烃脱氢制烯的方法，其特征在于，将烷烃原料和权利要求1～6任一项所述制备方法制得的催化剂接触，进行脱氢反应，制得相应的烯烃产物。A method for producing alkenes by dehydrogenating alkanes, characterized in that the raw materials of alkanes are contacted with the catalyst prepared by the preparation method according to any one of claims 1 to 6, and a dehydrogenation reaction is carried out to obtain corresponding alkenes.
  9. 如权利要求8所述的烷烃脱氢制烯的方法，其特征在于，所述的烷烃原料为具有式1结构式的化合物：The method for alkane dehydrogenation to olefins as claimed in claim 8, wherein the alkane raw material is a compound having the structural formula of Formula 1:
    Figure PCTCN2021099761-appb-100001
    Figure PCTCN2021099761-appb-100001
    其中，R 1～R 4独自为H、C 1～C 10的烷基、C 3～C 10的环烷基或芳基；或者，R 1与R 4相互环合形成环基； Wherein, R 1 to R 4 are independently H, C 1 to C 10 alkyl, C 3 to C 10 cycloalkyl or aryl; or, R 1 and R 4 are ringed with each other to form a ring group;
    所述的烷基、环烷基、环基或芳基上允许带有取代基，所述的取代基为C 1～C 6的烷基、C 1～C 6的烷氧基、卤素、苯基、硝基、三氟甲基中的至少一种取代基； The alkyl group, cycloalkyl group, ring group or aryl group are allowed to have substituents, and the substituents are C 1 -C 6 alkyl, C 1 -C 6 alkoxy, halogen, benzene At least one substituent in radical, nitro, trifluoromethyl;
    优选地，所述的芳基为苯环、五元杂环芳基、六元杂环芳基、或者由苯环、五元杂环芳基、六元杂环芳基中的两个及以上芳香环并合形成的稠环；Preferably, the aryl group is a benzene ring, a five-membered heterocyclic aryl group, a six-membered heterocyclic aryl group, or two or more A condensed ring formed by merging aromatic rings;
    优选地，所述的烷烃原料为具有式1-1结构的化合物；Preferably, the alkane raw material is a compound having the structure of formula 1-1;
    Figure PCTCN2021099761-appb-100002
    Figure PCTCN2021099761-appb-100002
    式1-1中，R 1为H、C 1～C 6的烷基、苯基或者取代苯基；所述的取代苯基的苯环上含有C 1～C 6的烷基、C 1～C 6的烷氧基、卤素、苯基、硝基、三氟甲基中的至少一种取代基。 In formula 1-1, R 1 is H, C 1 -C 6 alkyl, phenyl or substituted phenyl; the phenyl ring of the substituted phenyl contains C 1 -C 6 alkyl, C 1 -C 6 At least one substituent of C6 alkoxy, halogen, phenyl, nitro, trifluoromethyl.
  10. 如权利要求8或9所述的烷烃脱氢制烯的方法，其特征在于，The method for alkane dehydrogenation to olefins as claimed in claim 8 or 9, characterized in that,
    脱氢反应在无水条件下进行；或者在含弱氧气氛下进行；The dehydrogenation reaction is carried out under anhydrous conditions; or carried out under an atmosphere containing weak oxygen;
    优选地，脱氢反应在有氧气氛或者无氧气氛下进行；Preferably, the dehydrogenation reaction is carried out under an oxygen atmosphere or an oxygen-free atmosphere;
    优选地，脱氢反应的温度为500～700℃；优选为550～650℃。Preferably, the temperature of the dehydrogenation reaction is 500-700°C; preferably 550-650°C.
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