CN113058608A

CN113058608A - Catalyst for preparing isopropylbenzene by hydrogenolysis of alpha-dimethyl benzyl alcohol and preparation method thereof

Info

Publication number: CN113058608A
Application number: CN202010003288.3A
Authority: CN
Inventors: 沙宇; 李庆志; 韩红宇; 冉令卫; 崔桐; 卜令军; 詹吉山; 李作金; 于海波; 燕宸; 孙康; 黎源
Original assignee: Wanhua Chemical Group Co Ltd
Current assignee: Wanhua Chemical Group Co Ltd
Priority date: 2020-01-02
Filing date: 2020-01-02
Publication date: 2021-07-02
Anticipated expiration: 2040-01-02
Also published as: CN113058608B

Abstract

The invention provides a catalyst for preparing isopropylbenzene by hydrogenolysis of alpha-dimethyl benzyl alcohol and a preparation method thereof, wherein the preparation method comprises the steps of adding water and an organic pore-forming agent into a reaction kettle, and uniformly stirring to form water dispersion; preparing a mixed salt solution of copper salt, zinc salt, zirconium salt and alkaline earth metal salt and an alkaline precipitator, adding the mixed salt solution and the alkaline precipitator into the aqueous dispersion of the organic pore-forming agent together, and obtaining the catalyst through precipitation reaction, aging, filtering, washing, drying, roasting and forming; the invention also discloses a prepared catalyst and application thereof, wherein zirconia is used as a catalyst carrier, an organic pore-forming agent is added before the precipitation process, Zn and alkaline earth metal are used for modifying the catalyst, and when the catalyst is used for preparing isopropylbenzene by hydrogenolysis of alpha-dimethyl benzyl alcohol, the activity is high, the selectivity is good, the liquid resistance of the catalyst is effectively improved, and the catalyst has high strength and good stability.

Description

Catalyst for preparing isopropylbenzene by hydrogenolysis of alpha-dimethyl benzyl alcohol and preparation method thereof

Technical Field

The invention belongs to the technical field of catalysis, and particularly relates to a catalyst for preparing isopropylbenzene by hydrogenolysis of alpha-dimethyl benzyl alcohol, a preparation method and application.

Background

Propylene Oxide (PO) is an important organic chemical raw material, and is mainly used for producing polyether polyol (polyurethane raw material), propylene glycol and the like, and also is used for producing a large amount of nonionic surfactants, oil field demulsifiers, pesticide emulsifiers, developers and the like.

Industrial PO production methods mainly include a chlorohydrin process, a hydrogen peroxide direct oxidation process, and a co-oxidation process (Halcon process). The chlorohydrin method is a main route for producing PO in China, and the process has the problems of serious equipment corrosion, environmental pollution and the like. The direct hydrogen peroxide oxidation route suffers from high raw material cost and economic impact.

The co-oxidation method is also called co-production method or indirect oxidation method, and is to generate propylene oxide and byproduct organic alcohol through the reaction of organic peroxide and propylene. Although the traditional isobutane co-oxidation method and the ethylbenzene co-oxidation method avoid serious pollution of a chlorohydrin method with high investment and long process flow to the environment, a large amount of co-production byproducts are generated in the PO production process, and the production cost of PO is greatly influenced by the price fluctuation of the co-production products.

The cumene co-oxidation process (PO-CHP process) was first proposed by czech (CS140743), and was first commercialized by sumitomo chemical corporation of japan in 2003. The method comprises three core reactions of cumene peroxidation, propylene epoxidation and dimethyl benzyl alcohol hydrogenolysis and related separation procedures, wherein cumene hydroperoxide is used as an oxygen source, the coproduced dimethyl benzyl alcohol is subjected to hydrogenolysis to generate the cumene hydroperoxide, the cumene hydroperoxide returns to a peroxidation unit to react to obtain the cumene hydroperoxide, and the cumene hydroperoxide is recycled.

Compared with other processes, the cumene co-oxidation method has the advantages of high conversion rate and selectivity, short process route, less equipment investment, no coproduct, more stable economic benefit and the like. The hydrogenolysis reaction of dimethyl benzyl alcohol is one of the core reactions of the PO-CHP process, which is related to the consumption of cumene in the process, the relevant separation process and the like, and the performance of the hydrogenolysis catalyst of the dimethyl benzyl alcohol has obvious influence on the economy of the process.

The dimethyl benzyl alcohol hydrogenolysis catalyst mainly comprises a platinum-palladium noble metal catalyst, a nickel-based catalyst, a copper-based catalyst and the like, and the noble metal catalyst and the nickel-based catalyst have high cost, are easy to cause aromatic ring saturation and have poor isopropyl benzene selectivity.

Catalysts for the hydrogenolysis of dimethylbenzyl alcohol to cumene have been reported in many patents. U.S. Pat. No. 3,3337646 proposes a method for preparing isopropylbenzene by gas phase hydrogenolysis of alpha, alpha-dimethyl benzyl alcohol, which adopts Ni-Cr-Al2O3 catalyst to carry out gas phase hydrogenolysis on benzyl alcohol to isopropylbenzene at 350 ℃, the catalyst adopted in the patent contains Cr, and the preparation, use and recovery treatment processes of the catalyst have serious environmental pollution problems.

Patent CN1308273C discloses a method for preparing cumene by catalytic hydrogenolysis of alpha, alpha-dimethylbenzyl alcohol, the patent adopts 2 wt% of Pd-C catalyst, the cost of the catalyst is higher, substances such as halogenated aromatic hydrocarbon, sodium formate, formic acid, indole and quinoline need to be introduced during the reaction, and the separation difficulty and the cost are increased.

Patent CN1616383A proposes that noble metal Pd is used as a catalyst, H2 or an organic matter is used as a hydrogen source, the conversion rate of alpha, alpha-dimethylbenzyl alcohol is more than 96% and the selectivity of isopropyl benzene is more than 99% at 30-100 ℃, the method stays in a laboratory batch reaction stage, acetic acid and ethanol are added as solvents during reaction, the separation is complex, the Pd content in the catalyst is up to 2 wt%, and the catalyst cost is high.

Patent CN104230642A discloses a method for preparing cumene by directly hydrogenolysis of alpha, alpha-dimethyl benzyl alcohol, wherein a Cu/Co/Ni modified Pd-C catalyst is adopted, the selectivity of the cumene generated by hydrogenolysis reaction is generally less than 98.5 percent, the cost of the catalyst is high, and the selectivity is low.

Patent CN104230640A discloses a method for preparing isopropylbenzene by hydrogenolysis of alpha, alpha-dimethyl benzyl alcohol, which adopts Mg/Ca/Ba modified Pd-Ni/SiO2 catalyst, the selectivity of the isopropylbenzene generated by hydrogenolysis reaction is generally less than 98.5 percent, the cost of the catalyst is high, and the selectivity is low.

Patent CN104874406 discloses a Pt-loaded hydrogenolysis catalyst, which takes phenolic resin-based activated carbon as a carrier, the catalyst preparation process is complex, the amplification preparation difficulty is large, the catalyst selectivity is obviously reduced after the catalyst is operated for 300 hours, and the catalyst stability is poor.

Patent CN108947757A discloses a method for preparing cumene by catalytic hydrogenolysis of alpha, alpha-dimethylbenzyl alcohol, NiB-Zn/ZIF-8 is used as a catalyst, the conversion rate of dimethylbenzyl alcohol is 100%, and the selectivity of cumene is more than 96.8%, but the preparation process of the catalyst is complex and has no related report on catalyst stability.

Compared with noble metal catalysts and nickel catalysts, the copper catalysts have the advantages of high activity and selectivity, low cost and the like when used for the hydrogenolysis reaction of dimethylbenzyl alcohol, so the Cu catalysts are widely concerned, and the catalysts such as Cu-Zn, Cu-Zn-Al, Cu-Si, Cu-Cr and the like are researched more. However, since the simple substance Cu has a low melting point and a weak acting force with the carrier, and is easy to grow and deactivate due to sintering and agglomeration, the problems of poor mechanical stability, poor heat resistance, short service life and the like generally exist in the use process, and therefore, the development of a Cu-based catalyst with high efficiency and good stability is an urgent problem to be solved.

Japanese Sumitomo chemical company patent No. US6646139B2 discloses a process for preparing cumene by catalytic hydrogenolysis of alpha, alpha-dimethylbenzyl alcohol using a Cu-Cr catalyst, the conversion of alpha, alpha-dimethylbenzyl alcohol reaches 100%, and the selectivity of cumene exceeds 97.5%. The Cu-Cr catalyst has a Cr component, so that the problems of serious environmental pollution exist in the preparation, use and recovery processes of the catalyst. Patent CN1257138C proposes a method for reducing Cu catalyst by using H2 mixed gas with CO, and the catalyst used is still Cu — Cr catalyst, and there is no indication of catalyst stability.

Patent CN101992098 discloses a Cu-Zn-Al catalyst for preparing isopropylbenzene by hydrogenolysis of dimethyl benzyl alcohol, and the space velocity adopted by the patent is 1.5h^-1The space velocity is low and the patent does not disclose the state of the catalyst after use and the catalyst strength.

The active center of the copper catalyst is the reduced copper crystal grain, and because the melting point of the copper is lower, the growth and sintering of the copper crystal grain often occur in the reaction process, which directly results in the reduction of the number of active sites of the catalyst and the reduction of the activity of the catalyst. The reduction of hydrogenolysis activity can induce side reactions such as polymerization and the like to occur, so that the active sites of the catalyst are covered by the polymer, and the pore channels of the carrier are blocked by the polymer, thereby reducing the activity and stability of the catalyst.

In the prior art, the copper catalyst for hydrogenolysis reaction is not only acted by various internal or external forces in the processes of storage, filling, reduction, reaction and the like, but also the actual use strength of the catalyst is greatly reduced due to liquid soaking, swelling and the like, so that the catalyst is easy to break and pulverize in a liquid phase system, the service life of the catalyst is influenced, and the stable operation of an industrial device is threatened.

At present, when the Cu-series catalyst prepared by the prior art is used for preparing cumene by catalytic hydrogenolysis of dimethyl benzyl alcohol, the problems of low copper dispersity of an active component, strong acidity of the catalyst, weak interaction force between a carrier and the active component and the like exist, so that the problems of low activity of the catalyst, poor high-temperature stability, poor liquid resistance and serious environmental pollution are caused. Therefore, the method has great significance for preparing the dimethylbenzyl alcohol hydrogenolysis catalyst with high activity, high selectivity and high liquid resistance by improving the dispersion degree of the active component copper and the mass transfer performance of the catalyst, inhibiting the acidity of the catalyst and improving the liquid resistance of the catalyst.

Disclosure of Invention

Aiming at the problems in the prior art, the invention provides the catalyst for preparing the isopropylbenzene by the hydrogenolysis of the alpha-dimethyl benzyl alcohol and the preparation method thereof, the catalyst prepared by the method obviously inhibits side reactions such as recombination and the like, and has high activity and good selectivity; meanwhile, the catalyst has excellent liquid resistance, has high strength after reduction and liquid phase hydrogenation reaction, and can effectively reduce the loss phenomenon of active components in the reaction process.

In order to achieve the purpose, the technical scheme of the invention is as follows:

a catalyst for the hydrogenolysis of α α -dimethylbenzyl alcohol to cumene, the catalyst comprising the following components, based on the total weight of the catalyst (calculated as inorganic oxides, excluding organic impurities), of 100 wt.%:

copper 35-70 wt%, preferably 40-65 wt%, such as 40%, 50%, 60%, 65%;

zinc 5-25 wt%, such as 10%, 15%, 20%, 25%, preferably 10-20 wt%;

zirconium 15-40 wt%, preferably 20-35 wt%, such as 20%, 25%, 30%, 35%;

0.5-15 wt.%, preferably 1-10 wt.%, such as 1%, 3%, 5%, 10%;

the alkaline earth metal is selected from at least one of Mg, Ca and Ba,

wherein copper is calculated as copper oxide, zinc is calculated as zinc oxide, and zirconium is calculated as zirconium dioxide.

In the catalyst, Cu is an active component of the catalyst; the addition of the auxiliary Zn effectively improves the dispersion degree of the active component Cu in the preparation process of the catalyst, can effectively improve the hydrogenolysis reaction activity of the catalyst, and simultaneously, copper and zinc are easy to form copper-zinc solid solution in the processes of precipitation, drying and roasting, so that the loss phenomenon of the active component copper in the reaction process can be effectively prevented. The addition of the alkaline earth metal obviously reduces the acidity of the catalyst, and is beneficial to the improvement of the selectivity of hydrogenolysis reaction, meanwhile, zirconium is very necessary to be used as a catalyst carrier, and zirconium is used as a stable metal material, has very weak acid-base property and is beneficial to reducing the generation of byproducts such as recombinant products.

The invention also provides a preparation method of the hydrogenolysis catalyst, which can be used for preparing the hydrogenolysis catalyst and comprises the following steps:

(1) adding water (preferably deionized water) and an organic pore-forming agent into a reaction kettle, and uniformly stirring to prepare a dispersion liquid;

(2) dissolving copper salt, zinc salt, zirconium salt and alkaline earth metal salt in water to prepare mixed salt solution; dissolving an alkaline precipitator in water to prepare an alkaline precipitator aqueous solution; adding the mixed salt solution and an alkaline precipitant aqueous solution into the aqueous dispersion for reaction, controlling the pH of a reaction system to be 5.0-9.0 in the reaction process, and then aging to obtain slurry;

(3) filtering and washing the slurry to obtain a filter cake;

(4) and drying, roasting and forming the filter cake to obtain the catalyst.

In the invention, the step (1) is to mix the deionized water and the organic pore-forming agent uniformly to prepare the aqueous dispersion containing the organic pore-forming agent, and the solid content in the dispersion can be 0.5-10 wt%, preferably 1-5 wt%. Wherein, the organic pore-forming agent is preferably selected from one or more of PMMA (polymethyl methacrylate), microcrystalline cellulose and methyl cellulose; the organic pore-forming agent is added in the preparation process, so that the internal diffusion resistance of the raw materials and the product is reduced, and the activity and the selectivity are effectively improved.

According to the preparation method of the present invention, preferably, the particle size of the organic pore-forming agent is less than 100 μmm, more preferably 1 to 80 μm, further preferably 3 to 30 μm, such as 5, 10, 15, 20 or 25 μm; the particle size of the organic pore-forming agent is kept in a proper range, which is beneficial to further improving the diffusion mass transfer effect of the raw materials and the product; too large a particle size is not conducive to effective improvement of mass transfer performance, and too small a particle size is not conducive to improvement of mass transfer performance.

According to the preparation method of the present invention, the organic pore-forming agent is preferably used in an amount of 0.5 to 20 wt%, more preferably 1 to 10 wt%, and still more preferably 2 to 5 wt%, based on the total weight (theoretical calculation value) of the catalyst. The addition amount of the organic pore-forming agent is kept in a proper range, so that the influence on the strength of the catalyst is reduced as much as possible on the premise of obtaining better mass transfer performance; the addition amount of the organic pore-forming agent is too small, so that the effect of improving the catalyst mass transfer performance is not facilitated; too much pore former addition affects the mechanical strength of the catalyst.

In the present invention, the precipitant is a substance that can react with metal cations in a mixed salt solution to form a corresponding precipitate. And (2) preparing a mixed salt solution and an alkaline precipitant aqueous solution, and adding the mixed salt solution and the alkaline precipitant aqueous solution into the organic pore-forming agent-containing aqueous dispersion together so as to form corresponding precipitate from the mixed salt in the organic pore-forming agent-containing aqueous dispersion. Research shows that the pore-forming agent is dispersed in the water solution in advance and then forms a precipitate in the water solution, which is beneficial to better dispersion of the pore-forming agent in the precipitate. The total concentration of the mixed salt (copper salt, zinc salt, zirconium salt, alkaline earth metal salt) solution may be 5 to 50 wt%, each in such a ratio that the loading amount of copper, zinc, zirconium, alkaline earth metal oxide satisfies the above-mentioned specifications for the catalyst component (e.g., copper salt concentration of 5 to 20 wt%, zinc salt concentration of 1 to 10 wt%, zirconium salt concentration of 5 to 20 wt%, alkaline earth metal salt concentration of 0.1 to 5 wt%). The concentration of the aqueous alkaline precipitant solution may be 1 to 20 wt%.

According to the preparation method of the present invention, preferably, the alkaline precipitant is a silicon-free alkaline precipitant, preferably one or more of potassium carbonate, sodium bicarbonate, potassium bicarbonate, sodium hydroxide, potassium hydroxide, ammonium carbonate, ammonium bicarbonate, urea, and ammonia water.

It will be appreciated by those skilled in the art that in the present invention, each metal salt forming the mixed salt solution is a soluble salt of the corresponding metal (preferably having a solubility in water of 1% or more). According to the preparation method of the present invention, preferably, the copper salt is one or more of copper nitrate, copper chloride and copper acetate; the zinc salt is one or more of zinc nitrate, zinc chloride and zinc acetate; the zirconium salt is one or more of zirconium nitrate and zirconium chloride, and the alkaline earth metal salt is one or more of nitrate, chloride and acetate, preferably one or more of magnesium nitrate, magnesium chloride, magnesium acetate, calcium nitrate, calcium chloride, calcium acetate, barium nitrate, barium chloride and barium acetate.

In the invention, Zn and Cu can form a solid solution in the preparation process, which can effectively promote the dispersion of the active component copper in the catalyst and reduce the loss of the active component; the addition of the alkaline earth metal obviously inhibits the acidity of the catalyst, can effectively inhibit the generation of heavy components and improve the reaction selectivity, and preferably, the alkaline earth metal is one or two or more of magnesium, calcium and barium. It is understood by those skilled in the art that the amount of each metal component added may be an amount corresponding to the oxide content of each metal component in the prepared catalyst to the target content.

In the step (2), controlling the pH value of a reaction system in the reaction process to be 5.0-9.0, such as 5.5-8.0, and then aging to obtain slurry; preferably, the temperature of the reaction process and the aging process is controlled to be 60 to 90 ℃, such as 70 or 80 ℃. The specific reaction to form a precipitate and the aging of the precipitate are well known in the art, and for example, the reaction to form a precipitate can be completed within 1 to 3 hours and then aged for another 1 to 3 hours.

In the invention, the step (3) is to filter and wash the slurry to obtain a filter cake; the filtration and washing processes can adopt filtration and washing processes commonly used in the field, and are catalyst treatment processes commonly used in the field.

In the present invention, the calcination temperature in step (4) is 300-700 ℃, such as 400, 500 or 600 ℃; the roasting time is 4-12h, such as 6, 8 or 10 h; the molding may be tablet molding or the like.

Meanwhile, the invention also provides the application of the catalyst in the preparation of isopropylbenzene by the hydrogenolysis of alpha-dimethyl benzyl alcohol. Alpha-dimethyl benzyl alcohol is used as a starting material and subjected to hydrogenolysis reaction under the action of the catalyst or the catalyst prepared by the method to prepare the isopropylbenzene.

In the above method, the hydrogenolysis reaction is preferably carried out in the presence of a solvent, preferably cumene, in a mass ratio of the solvent to α -dimethylbenzyl alcohol in a range of 1: 2 to 4.

In the method, the hydrogenolysis reaction is carried out at the pressure of 1-2 MPa (gauge pressure), the temperature of 140-160 ℃ and H₂The volume ratio of the alpha-dimethyl benzyl alcohol to the DMPC (alpha-dimethyl benzyl alcohol) is 300-500: 1, and the liquid hourly space velocity is 1-3h^-1。

Preferably, the catalyst of the present invention comprises a reduction activation treatment before use.

In a preferred embodiment, the method for reductive activation of a catalyst according to the present invention comprises: preferably, the temperature of the reactor is increased to 200-230 ℃, the temperature is kept constant for 1-2H to remove the physical water adsorbed by the catalyst, and then H with the volume fraction not more than 10v percent is introduced₂For example (5 v% + -2 v%) H₂The catalyst is pre-reduced for at least 0.5h, such as 1h, 1.5h or 2h, the proportion of the hydrogen in the hydrogen and nitrogen mixed gas is gradually increased, such as gradually increased to 10 v%, 20 v%, 50 v% and 100%, the temperature of a hot spot of a catalyst bed layer in the process is controlled not to exceed 260 ℃, finally the catalyst is reduced for 2-5 h, such as 3 or 4h, in the reduction activation process, the gas volume space velocity is kept for 300-1000 h^-1And obtaining the activated catalyst.

In the method, the conversion rate of the raw material alpha-dimethyl benzyl alcohol is more than 99 percent; the selectivity of the isopropyl benzene is more than 99 percent; the catalyst has the advantages of stable service life of more than 1000h, good strength maintenance, low temperature and high activity, and obviously reduced side reaction generation amount and excellent product selectivity due to relatively low reaction temperature.

The invention has the beneficial effects that:

compared with the prior art, when the catalyst prepared by the invention is used for preparing cumene by hydrogenolysis of dimethyl benzyl alcohol, the active components of the catalyst are uniformly distributed, the dispersion degree of copper is high, the pore passage of the catalyst is smooth, the acidity is weak, the catalyst has excellent activity, selectivity, stability and mechanical strength, and the conversion rate can reach more than 99.9 percent and the selectivity is more than 99 percent.

In addition, the catalyst prepared by the method disclosed by the invention has the advantages that the mass transfer performance of the catalyst can be effectively improved by adding the pore-forming agent, and the activity of the catalyst is favorably improved; the Zn and the alkaline earth metal in the catalyst composition are added to improve the dispersion degree of the active component Cu, inhibit the acidity of the catalyst, improve the activity and the selectivity of the catalyst, reduce the loss phenomenon of the active component and prolong the service life of the catalyst, and meanwhile, the zirconium is used as a catalyst carrier to ensure that the catalyst has better mechanical strength and liquid resistance and is favorable for reducing the generation of byproducts.

Detailed Description

The advantageous effects of the present invention will be described below by way of specific examples. It will be appreciated by those skilled in the art that the examples are only intended to illustrate the invention and are not intended to limit the scope of the invention. In the examples, the means used are conventional in the art unless otherwise specified.

< sources of raw materials >

Cumene, purchased from Shanghai Allantin Biotechnology GmbH;

ethylbenzene, available from Shanghai Aladdin Biotechnology, Inc.;

dimethylbenzyl alcohol, available from echiicai chemical synthesis industries, ltd.

< test methods >

1. Analyzing the composition of the dimethyl benzyl alcohol hydrogenolysis catalyst by adopting an X-ray fluorescence spectrometer (XRF);

2. conversion of dimethylbenzyl alcohol (1-mole of dimethylbenzyl alcohol remaining in reaction solution/mole of dimethylbenzyl alcohol contained in raw material) × 100%;

cumene selectivity-100% moles of cumene formed/moles dimethylbenzyl alcohol converted;

wherein, the mole number of dimethyl benzyl alcohol contained in the raw material, the mole number of generated isopropyl benzene and the mole number of the dimethyl benzyl alcohol remained in the reaction solution are calculated after being analyzed by an Agilent 7820A gas chromatograph, and the test conditions comprise: adopts DB-5 chromatographic column and FID detector, the vaporizing chamber temperature is 260 deg.C, the detector temperature is 260 deg.C, and the carrier gas is high-purity N₂The flow rate was 30 ml/min.

The lateral pressure strength of the catalyst is measured by a particle strength tester, the used catalyst is protected by soaking with ethylbenzene to prevent the catalyst from being oxidized, the lateral pressure strength of the catalyst after 40-grain reaction is measured, and the average value is taken.

The content of copper ions in the reaction solution was measured by inductively coupled plasma emission spectrometer (ICP).

The content of elements in the catalyst is measured by an inductively coupled plasma emission mass spectrometer (ICP).

The zirconium nitrate used in the examples was zirconium nitrate pentahydrate; the calcium nitrate is calcium nitrate tetrahydrate; the zinc nitrate is zinc nitrate hexahydrate.

Example 1:

a preparation method of a hydrogenolysis catalyst comprises the following steps:

200g of water and 4.0g of PMMA with the particle size of 10-30 mu m are added into a reaction kettle and uniformly mixed, 332.2g of copper nitrate, 81.3g of zinc nitrate, 150g of zirconium nitrate and 12.7g of magnesium nitrate are dissolved in 1.5kg of water to prepare mixed salt water solution, 142.5g of sodium carbonate is dissolved in water to prepare precipitant solution with the concentration of 15 wt%, and the two solutions are respectively heated to 70 ℃. The two solutions are dropped into a reaction kettle simultaneously by adopting a coprecipitation method, the temperature in the kettle is controlled to be 70 ℃, the pH value of the system is controlled to be 7.0, and the reaction time is controlled to be 1 h. After the two solutions are dripped, the pH value of the system is adjusted to be more than 7.5 by using a 10 wt% sodium carbonate solution, the system is aged for 3h at the temperature of 75 ℃, then the system is filtered and washed, a filter cake is dried for 12h at the temperature of 110 ℃, the filter cake is roasted for 8h at the temperature of 350 ℃, and then a certain amount of graphite is mixed and pressed into a 3 x 3mm cylinder (with the diameter of 3mm and the height of 3mm) catalyst, thus obtaining the catalyst A.

The catalyst A comprises the following components: 67.3 wt% of copper oxide and 10.6 wt% of zinc oxide; 20.5 wt% of zirconium dioxide; magnesium oxide (alkaline earth metal) 1.6 wt%.

And (3) catalyst reduction: catalyst A was loaded in a fixed bed hydrogenation reactor with a catalyst loading of 100 ml. Before the catalyst is used, the catalyst is reduced under the mixed gas of nitrogen and hydrogen, the volume space velocity of the mixed gas is kept at 300H < -1 > in the reduction process, the temperature of a reactor is firstly raised to 160 ℃, the temperature is kept constant for 2H, physical water adsorbed by the catalyst is removed, then the mixed gas of hydrogen and nitrogen containing H2 with the volume fraction of 5 v% is introduced for pre-reduction for 1H, then the proportion of hydrogen in the mixed gas of hydrogen and nitrogen is gradually increased to 10 v%, 20 v%, 50 v% and 100%, the hotspot temperature of a catalyst bed layer in the process is controlled not to exceed 220 ℃, and finally the temperature is raised to 220 ℃ for reduction for 3H under the pure hydrogen atmosphere.

Example 2

200g of water and 6.0g of microcrystalline cellulose with the grain diameter of 5-30 mu m are added into the reaction kettle and stirred uniformly. 200g of copper nitrate, 87.7g of zinc nitrate, 200g of zirconium nitrate and 4.21g of calcium nitrate are dissolved in 1.45kg of water to prepare a mixed saline solution, 149.0g of sodium carbonate is dissolved in water to prepare a precipitant solution with the concentration of 15 wt%, and the two solutions are respectively heated to 75 ℃. And (3) simultaneously dripping the two solutions into a reaction kettle by adopting a coprecipitation method, controlling the temperature in the kettle to be 75 ℃, the pH value of the system to be 7.2 and the reaction time to be 1h in the precipitation process. After the two solutions are dripped, the pH value of the system is adjusted to be more than 7.5 by using a 10 wt% sodium carbonate solution, the system is aged for 3h at the temperature of 80 ℃, then the system is filtered and washed, a filter cake is dried for 24h at the temperature of 100 ℃, the filter cake is roasted for 12h at the temperature of 400 ℃, and then a certain amount of graphite is mixed and pressed into a 3 x 3mm cylinder (with the diameter of 3mm and the height of 3mm) catalyst, thus obtaining the catalyst B.

The catalyst B comprises the following components: 50.7 wt% of copper oxide and 14.3 wt% of zinc oxide; 34.3 wt% of zirconium dioxide; 0.6 wt% of calcium oxide (alkaline earth metal).

The rest of the conditions refer to example 1.

Example 3

200g of water and 10.0g of methyl cellulose with the particle size of 5-20 mu m are added into the reaction kettle and mixed evenly. 302g of copper nitrate, 87.7g of zinc nitrate, 150g of zirconium nitrate and 6.8g of barium nitrate are dissolved in 1.37kg of water to prepare a mixed salt water solution, 150g of sodium carbonate is dissolved in water to prepare a precipitator solution with the concentration of 15 wt%, and the two solutions are respectively heated to 80 ℃. By adopting a coprecipitation method, the two solutions are simultaneously dripped into a reaction kettle, the temperature in the kettle in the precipitation process is controlled to be 80 ℃, the pH value of the system is controlled to be 8.0, and the reaction time is controlled to be 1 h. After the two solutions are dripped, the pH value of the system is adjusted to be more than 7.3 by using a 10 wt% sodium carbonate solution, the system is aged for 3h at 85 ℃, then the system is filtered and washed, a filter cake is dried for 12h at 120 ℃, the filter cake is roasted for 8h at 550 ℃, and then a certain amount of graphite is mixed and pressed into a 3 x 3mm cylinder (with the diameter of 3mm and the height of 3mm) catalyst, thus obtaining the catalyst C.

The catalyst C comprises the following components: 64.3 wt% of copper oxide and 12.1 wt% of zinc oxide; zirconium dioxide 21.6 wt%; barium oxide (alkaline earth metal) 2 wt%.

The rest of the conditions refer to example 1.

Comparative example 1

200g of water and 10.0g of methyl cellulose with the particle size of 5-20 mu m are added into the reaction kettle and mixed evenly. 332.2g of copper nitrate and 200g of zirconium nitrate were dissolved in 1.5kg of water to prepare a mixed brine solution, a 10 wt% aqueous solution of sodium carbonate was prepared as a precipitant, and the two solutions were heated to 65 ℃. By adopting a coprecipitation method, the two solutions are simultaneously dripped into a reaction kettle, the temperature in the kettle in the precipitation process is controlled to be 65 ℃, the pH value of the system is controlled to be 7.0, and the reaction time is controlled to be 1 h. After the solution is dropwise added, the solution is aged for 3h at 70 ℃, then filtered, washed, and the filter cake is dried for 24h at 110 ℃, and roasted for 8h at 450 ℃, and then a certain amount of graphite is mixed and pressed into a 3 x 3mm cylindrical (with the diameter of 3mm and the height of 3mm) catalyst, so that the catalyst D is obtained.

The rest of the conditions refer to example 1.

Comparative example 2

322.2g of copper nitrate and 292.4g of zinc nitrate are dissolved in 1.65kg of water to prepare mixed salt water solution, sodium carbonate is dissolved in water to prepare 10 wt% sodium carbonate solution, and the two solutions are respectively heated to 65 ℃. And (2) dropping the two solutions into a reaction kettle simultaneously by adopting a coprecipitation method, controlling the temperature in the kettle to be 65 ℃ and the precipitation pH to be 7.0 in the precipitation process, aging the solution at 70 ℃ for 3h after the precipitation is finished, adding 10.0g of alumina into a filter cake obtained after filtering and washing, drying the filter cake at 110 ℃ for 12h, roasting the filter cake at 350 ℃ for 4h, and tabletting and forming the filter cake to obtain the 3 x 3mm cylindrical (the diameter is 3mm and the height is 3mm) catalyst, thus obtaining the catalyst E.

The rest of the conditions refer to example 1.

Comparative example 3

Catalyst F was prepared as in example 1 without the addition of an alkaline earth metal compound.

The rest of the conditions refer to example 1.

Comparative example 4

In the preparation process of the catalyst, the organic pore-forming agent PMMA is not added, and the catalyst G is prepared by the same method as the example 1.

The rest of the conditions refer to example 1.

When the catalyst prepared by the method is used in the industrial process for synthesizing cumene through hydrogenolysis of alpha, alpha-dimethyl benzyl alcohol, the problem of environmental pollution does not exist because the catalyst does not contain Cr element, 1000H evaluation is carried out under the reaction conditions that the reaction raw material composition (mass percentage content) is 75.0 percent of cumene, 25.0 percent of benzyl alcohol, the reaction pressure is 2MPa, the molar ratio of H2/benzyl alcohol is 8.0, and the volume space velocity of the raw material is 1.5/hour in a fixed bed reactor, and the reaction results are listed in Table 1:

TABLE 1 evaluation table of reactivity in preparation of isopropylbenzene by hydrogenolysis of benzyl alcohol

TABLE 2 catalyst comparison before and after reaction

N/catalyst is a unit of catalyst strength, i.e., the force applied to break 1 catalyst;

note: "not detected" means that the average copper ion content in the hydrogenated liquid was < 0.1. mu.g/g.

As can be seen from Table 1, the conversion rate of alpha, alpha-dimethyl benzyl alcohol is more than 99.0% and the selectivity of isopropyl benzene is more than 99.0% under the conditions of 190 ℃ and 2MPa, and the technology obtains good reaction results when the technology is used for the process of synthesizing isopropyl benzene by hydrogenolysis of alpha, alpha-dimethyl benzyl alcohol.

As is clear from tables 1 and 2, when catalysts a to C, and catalysts E and G were used, no copper ions were detected in the hydrogenation liquid, and the side pressure strengths were all 50N/pellet; in contrast, the catalysts of comparative example 1 and comparative example 2 have severe crushing and low lateral pressure strength after reaction; ICP analysis in the comparative example 1 shows that the content of copper in the hydrogenation liquid is higher, which indicates that the catalyst is obviously lost; catalysts a to C are highly active and can effectively suppress side reactions such as recombination, while the catalysts described in comparative examples 1 to 4 are not only low in activity but also poor in selectivity.

The above examples are only for describing the preferred embodiments of the present invention, and are not intended to limit the scope of the present invention, and various modifications and improvements made to the technical solution of the present invention by those skilled in the art without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A catalyst for preparing isopropylbenzene by hydrogenolysis of alpha-dimethyl benzyl alcohol comprises the following components by weight:

35-70 wt% copper, preferably 40-65 wt%;

5-25 wt%, preferably 10-20 wt% of zinc;

zirconium 15-40 wt%, preferably 20-35 wt%;

0.5 to 15 wt.%, preferably 1 to 10 wt.% of an alkaline earth metal oxide;

the alkaline earth metal is selected from at least one of Mg, Ca and Ba,

2. A method of preparing the catalyst of claim 1, comprising:

(1) adding water and an organic pore-forming agent into a reaction kettle, and uniformly stirring to prepare a dispersion liquid;

(3) filtering and washing the slurry to obtain a filter cake;

(4) and drying, roasting and forming the filter cake to obtain the catalyst.

3. The preparation method according to claim 2, wherein the organic pore former is selected from one or more of PMMA, microcrystalline cellulose and methyl cellulose.

4. The production method according to any one of claims 2 to 3, wherein the alkaline earth metal salt is selected from one or more of magnesium nitrate, magnesium chloride, magnesium acetate, calcium nitrate, calcium chloride, calcium acetate, barium nitrate, barium chloride, and barium acetate.

5. The production method according to any one of claims 2 to 4, wherein the alkaline precipitant is one or more of potassium carbonate, sodium bicarbonate, potassium bicarbonate, sodium hydroxide, potassium hydroxide, ammonium carbonate, ammonium bicarbonate, urea, and aqueous ammonia, and the copper salt is one or more of copper nitrate, copper chloride, and copper acetate; the zinc salt is one or more of zinc nitrate, zinc chloride and zinc acetate; the zirconium salt is one or more of zirconium nitrate and zirconium chloride.

6. The method according to any one of claims 2 to 5, wherein the organic pore-forming agent has a particle size of < 100 μmm, preferably 1 to 80 μm, more preferably 3 to 30 μm; and/or

The organic pore-forming agent is used in an amount of 0.5 to 20 wt%, more preferably 1 to 10 wt%, and further preferably 2 to 5 wt% based on the total weight of the catalyst.

7. The method according to any one of claims 2 to 6, wherein the temperature of the reaction process and the aging process of step (2) is 60 to 90 ℃; the roasting temperature in the step (4) is 300-700 ℃, and the roasting time is 4-12 h.

8. The method according to any one of claims 2 to 7, characterized by comprising, before use, a reductive activation treatment of the catalyst obtained in step (4).

9. Use of the catalyst of claim 1 or obtained by the preparation process of any one of claims 2 to 8 in the hydrogenolysis of α α -dimethylbenzyl alcohol to cumene.

10. A method for preparing isopropylbenzene by hydrogenolysis of alpha-dimethylbenzyl alcohol, comprising: cumene is produced by hydrogenolysis of α α -dimethylbenzyl alcohol as a starting material in the presence of the catalyst of claim 1 or the catalyst obtained by the production method of any one of claims 2 to 8.