CN117945904A - Method for preparing unsaturated carboxylic ester by utilizing multistage condensation reaction, reaction system and obtained product - Google Patents
Method for preparing unsaturated carboxylic ester by utilizing multistage condensation reaction, reaction system and obtained product Download PDFInfo
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- 238000006243 chemical reaction Methods 0.000 title claims abstract description 106
- 238000006482 condensation reaction Methods 0.000 title claims abstract description 85
- 150000001733 carboxylic acid esters Chemical class 0.000 title claims abstract description 51
- 238000000034 method Methods 0.000 title claims abstract description 47
- BAPJBEWLBFYGME-UHFFFAOYSA-N Methyl acrylate Chemical compound COC(=O)C=C BAPJBEWLBFYGME-UHFFFAOYSA-N 0.000 claims abstract description 113
- WSFSSNUMVMOOMR-UHFFFAOYSA-N Formaldehyde Chemical compound O=C WSFSSNUMVMOOMR-UHFFFAOYSA-N 0.000 claims abstract description 111
- 238000006297 dehydration reaction Methods 0.000 claims abstract description 103
- 230000018044 dehydration Effects 0.000 claims abstract description 102
- 239000003054 catalyst Substances 0.000 claims abstract description 85
- XBDQKXXYIPTUBI-UHFFFAOYSA-M Propionate Chemical compound CCC([O-])=O XBDQKXXYIPTUBI-UHFFFAOYSA-M 0.000 claims abstract description 60
- KXKVLQRXCPHEJC-UHFFFAOYSA-N acetic acid trimethyl ester Natural products COC(C)=O KXKVLQRXCPHEJC-UHFFFAOYSA-N 0.000 claims abstract description 60
- 239000002994 raw material Substances 0.000 claims abstract description 56
- -1 aldehyde compounds Chemical class 0.000 claims abstract description 44
- 239000000463 material Substances 0.000 claims abstract description 40
- 238000004519 manufacturing process Methods 0.000 claims abstract description 16
- 150000001299 aldehydes Chemical class 0.000 claims abstract description 7
- 150000001298 alcohols Chemical class 0.000 claims abstract description 6
- 229920006395 saturated elastomer Polymers 0.000 claims abstract description 5
- 230000000153 supplemental effect Effects 0.000 claims abstract description 4
- 238000009833 condensation Methods 0.000 claims description 130
- 230000005494 condensation Effects 0.000 claims description 130
- 208000005156 Dehydration Diseases 0.000 claims description 102
- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 claims description 78
- 239000012024 dehydrating agents Substances 0.000 claims description 26
- 238000002360 preparation method Methods 0.000 claims description 25
- 150000003839 salts Chemical class 0.000 claims description 25
- 239000007787 solid Substances 0.000 claims description 21
- 239000000203 mixture Substances 0.000 claims description 19
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 16
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 12
- 239000011259 mixed solution Substances 0.000 claims description 10
- UUIQMZJEGPQKFD-UHFFFAOYSA-N Methyl butyrate Chemical compound CCCC(=O)OC UUIQMZJEGPQKFD-UHFFFAOYSA-N 0.000 claims description 9
- RJUFJBKOKNCXHH-UHFFFAOYSA-N Methyl propionate Chemical compound CCC(=O)OC RJUFJBKOKNCXHH-UHFFFAOYSA-N 0.000 claims description 8
- 238000005470 impregnation Methods 0.000 claims description 8
- 229940017219 methyl propionate Drugs 0.000 claims description 8
- 230000008569 process Effects 0.000 claims description 8
- VVQNEPGJFQJSBK-UHFFFAOYSA-N Methyl methacrylate Chemical compound COC(=O)C(C)=C VVQNEPGJFQJSBK-UHFFFAOYSA-N 0.000 claims description 7
- 238000001035 drying Methods 0.000 claims description 7
- 238000011068 loading method Methods 0.000 claims description 7
- QAOWNCQODCNURD-UHFFFAOYSA-L Sulfate Chemical compound [O-]S([O-])(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-L 0.000 claims description 6
- HUCVOHYBFXVBRW-UHFFFAOYSA-M caesium hydroxide Chemical compound [OH-].[Cs+] HUCVOHYBFXVBRW-UHFFFAOYSA-M 0.000 claims description 6
- 150000003863 ammonium salts Chemical class 0.000 claims description 4
- NLSCHDZTHVNDCP-UHFFFAOYSA-N caesium nitrate Inorganic materials [Cs+].[O-][N+]([O-])=O NLSCHDZTHVNDCP-UHFFFAOYSA-N 0.000 claims description 4
- 229910000365 copper sulfate Inorganic materials 0.000 claims description 4
- ARUVKPQLZAKDPS-UHFFFAOYSA-L copper(II) sulfate Chemical compound [Cu+2].[O-][S+2]([O-])([O-])[O-] ARUVKPQLZAKDPS-UHFFFAOYSA-L 0.000 claims description 4
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 3
- 229910052799 carbon Inorganic materials 0.000 claims description 3
- 229910052681 coesite Inorganic materials 0.000 claims description 3
- 229910052906 cristobalite Inorganic materials 0.000 claims description 3
- 238000010304 firing Methods 0.000 claims description 3
- 239000000377 silicon dioxide Substances 0.000 claims description 3
- 229910052682 stishovite Inorganic materials 0.000 claims description 3
- 229910052905 tridymite Inorganic materials 0.000 claims description 3
- 125000006273 (C1-C3) alkyl group Chemical group 0.000 claims description 2
- 239000002253 acid Substances 0.000 claims description 2
- 229940103272 aluminum potassium sulfate Drugs 0.000 claims description 2
- RUTXIHLAWFEWGM-UHFFFAOYSA-H iron(3+) sulfate Chemical compound [Fe+3].[Fe+3].[O-]S([O-])(=O)=O.[O-]S([O-])(=O)=O.[O-]S([O-])(=O)=O RUTXIHLAWFEWGM-UHFFFAOYSA-H 0.000 claims description 2
- 229910000360 iron(III) sulfate Inorganic materials 0.000 claims description 2
- 239000007791 liquid phase Substances 0.000 claims description 2
- JKJJSJJGBZXUQV-UHFFFAOYSA-N methyl 2-methylidenebutanoate Chemical compound CCC(=C)C(=O)OC JKJJSJJGBZXUQV-UHFFFAOYSA-N 0.000 claims description 2
- GRLPQNLYRHEGIJ-UHFFFAOYSA-J potassium aluminium sulfate Chemical compound [Al+3].[K+].[O-]S([O-])(=O)=O.[O-]S([O-])(=O)=O GRLPQNLYRHEGIJ-UHFFFAOYSA-J 0.000 claims description 2
- 230000001502 supplementing effect Effects 0.000 abstract description 9
- 238000005516 engineering process Methods 0.000 abstract description 3
- YXFVVABEGXRONW-UHFFFAOYSA-N Toluene Chemical compound CC1=CC=CC=C1 YXFVVABEGXRONW-UHFFFAOYSA-N 0.000 description 36
- FJDQFPXHSGXQBY-UHFFFAOYSA-L caesium carbonate Chemical compound [Cs+].[Cs+].[O-]C([O-])=O FJDQFPXHSGXQBY-UHFFFAOYSA-L 0.000 description 14
- 229910000024 caesium carbonate Inorganic materials 0.000 description 14
- 239000011148 porous material Substances 0.000 description 14
- 239000002585 base Substances 0.000 description 13
- 238000004817 gas chromatography Methods 0.000 description 12
- 239000011541 reaction mixture Substances 0.000 description 12
- 238000005070 sampling Methods 0.000 description 12
- 239000000243 solution Substances 0.000 description 12
- 230000000052 comparative effect Effects 0.000 description 11
- 239000000047 product Substances 0.000 description 11
- ATRRKUHOCOJYRX-UHFFFAOYSA-N Ammonium bicarbonate Chemical compound [NH4+].OC([O-])=O ATRRKUHOCOJYRX-UHFFFAOYSA-N 0.000 description 10
- 239000001099 ammonium carbonate Substances 0.000 description 10
- 235000012501 ammonium carbonate Nutrition 0.000 description 10
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 8
- 239000004005 microsphere Substances 0.000 description 8
- 230000001105 regulatory effect Effects 0.000 description 8
- 239000012298 atmosphere Substances 0.000 description 7
- 238000007599 discharging Methods 0.000 description 6
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 description 5
- 238000002156 mixing Methods 0.000 description 5
- 229920005479 Lucite® Polymers 0.000 description 4
- 229910002092 carbon dioxide Inorganic materials 0.000 description 4
- 239000004926 polymethyl methacrylate Substances 0.000 description 4
- 230000015572 biosynthetic process Effects 0.000 description 3
- 238000001354 calcination Methods 0.000 description 3
- 239000001569 carbon dioxide Substances 0.000 description 3
- 230000003197 catalytic effect Effects 0.000 description 3
- 238000003786 synthesis reaction Methods 0.000 description 3
- 238000004438 BET method Methods 0.000 description 2
- ATUOYWHBWRKTHZ-UHFFFAOYSA-N Propane Chemical compound CCC ATUOYWHBWRKTHZ-UHFFFAOYSA-N 0.000 description 2
- 230000009849 deactivation Effects 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 239000006185 dispersion Substances 0.000 description 2
- 239000006052 feed supplement Substances 0.000 description 2
- TZIHFWKZFHZASV-UHFFFAOYSA-N methyl formate Chemical compound COC=O TZIHFWKZFHZASV-UHFFFAOYSA-N 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 229910052757 nitrogen Inorganic materials 0.000 description 2
- 230000003647 oxidation Effects 0.000 description 2
- 238000007254 oxidation reaction Methods 0.000 description 2
- NLHHRLWOUZZQLW-UHFFFAOYSA-N Acrylonitrile Chemical compound C=CC#N NLHHRLWOUZZQLW-UHFFFAOYSA-N 0.000 description 1
- VGGSQFUCUMXWEO-UHFFFAOYSA-N Ethene Chemical compound C=C VGGSQFUCUMXWEO-UHFFFAOYSA-N 0.000 description 1
- 239000005977 Ethylene Substances 0.000 description 1
- JGFBQFKZKSSODQ-UHFFFAOYSA-N Isothiocyanatocyclopropane Chemical compound S=C=NC1CC1 JGFBQFKZKSSODQ-UHFFFAOYSA-N 0.000 description 1
- 238000010521 absorption reaction Methods 0.000 description 1
- 125000005396 acrylic acid ester group Chemical group 0.000 description 1
- 230000006978 adaptation Effects 0.000 description 1
- 239000003513 alkali Substances 0.000 description 1
- PWLNAUNEAKQYLH-UHFFFAOYSA-N butyric acid octyl ester Natural products CCCCCCCCOC(=O)CCC PWLNAUNEAKQYLH-UHFFFAOYSA-N 0.000 description 1
- 239000006227 byproduct Substances 0.000 description 1
- 150000007942 carboxylates Chemical class 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000005265 energy consumption Methods 0.000 description 1
- 150000002148 esters Chemical class 0.000 description 1
- CCGKOQOJPYTBIH-UHFFFAOYSA-N ethenone Chemical compound C=C=O CCGKOQOJPYTBIH-UHFFFAOYSA-N 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 238000007037 hydroformylation reaction Methods 0.000 description 1
- 230000007062 hydrolysis Effects 0.000 description 1
- 238000006460 hydrolysis reaction Methods 0.000 description 1
- 238000011065 in-situ storage Methods 0.000 description 1
- 238000003541 multi-stage reaction Methods 0.000 description 1
- 239000012299 nitrogen atmosphere Substances 0.000 description 1
- 231100000252 nontoxic Toxicity 0.000 description 1
- 230000003000 nontoxic effect Effects 0.000 description 1
- 239000001294 propane Substances 0.000 description 1
- QQONPFPTGQHPMA-UHFFFAOYSA-N propylene Natural products CC=C QQONPFPTGQHPMA-UHFFFAOYSA-N 0.000 description 1
- 125000004805 propylene group Chemical group [H]C([H])([H])C([H])([*:1])C([H])([H])[*:2] 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- 239000013589 supplement Substances 0.000 description 1
- 230000002194 synthesizing effect Effects 0.000 description 1
- 238000010998 test method Methods 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C67/00—Preparation of carboxylic acid esters
- C07C67/30—Preparation of carboxylic acid esters by modifying the acid moiety of the ester, such modification not being an introduction of an ester group
- C07C67/333—Preparation of carboxylic acid esters by modifying the acid moiety of the ester, such modification not being an introduction of an ester group by isomerisation; by change of size of the carbon skeleton
- C07C67/343—Preparation of carboxylic acid esters by modifying the acid moiety of the ester, such modification not being an introduction of an ester group by isomerisation; by change of size of the carbon skeleton by increase in the number of carbon atoms
-
- 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
- B01J27/20—Carbon compounds
- B01J27/232—Carbonates
-
- 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
- B01J8/00—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
- Low-Molecular Organic Synthesis Reactions Using Catalysts (AREA)
Abstract
The invention discloses a method for preparing unsaturated carboxylic ester by utilizing multistage condensation reaction, a reaction system and an obtained product. The method comprises the steps of enabling raw materials of aldehyde compounds, alcohol compounds and saturated carboxylic ester compounds to undergo multistage condensation reaction in the presence of a catalyst to generate unsaturated carboxylic ester; adding supplementary material and optionally dewatering the material between the sections in the multistage condensation reaction; the supplemental raw materials include aldehydes and optionally alcohols. The invention takes methyl acetate or other carboxylic acid esters and formaldehyde as raw materials, adopts novel catalyst to synthesize methyl acrylate or other unsaturated carboxylic acid esters and adopts a multi-stage condensation reaction section-to-section aldehyde supplementing dehydration technology, so that the conversion rate of the methyl acetate or other carboxylic acid esters, the selectivity of the methyl acrylate or other unsaturated carboxylic acid esters and the stability of the catalyst are all improved, and the industrialized production of the methyl acrylate or other carboxylic acid esters is possible.
Description
Technical Field
The invention relates to the technical field of unsaturated carboxylic ester synthesis, in particular to a method for preparing unsaturated carboxylic ester by utilizing multistage condensation reaction, a reaction system and an obtained product.
Background
Among unsaturated carboxylic acid esters, the production method of acrylic acid esters in particular mainly includes propylene oxidation method, acrylonitrile hydrolysis method, ketene method, propane oxidation method, methyl formate method, and the like. However, the methods have the defects of serious pollution, high energy consumption, low product yield and the like. Therefore, the development of green and efficient new production processes has great significance.
Lu Caite (Lucite) proposes a mature process for preparing methyl acrylate by utilizing alpha-MMA through condensation reaction, lu Caite (Lucite) adopts a process for preparing methyl propionate by hydroformylation of ethylene, CO and methanol and then condensing with formaldehyde to obtain alpha-MMA, but a process route of Lu Caite (Lucite) is not suitable for national conditions of China. The national conditions of China are that the yield of methyl acetate is greatly excessive. However, the process route of the Louist company is to synthesize methyl methacrylate raw material from methyl propionate, and the consumed raw material is methyl propionate, so that the problem of surplus production capacity of methyl acetate in China cannot be solved. However, in the prior art, the single pass conversion rate of methyl acetate is generally 15%, the selectivity of methyl acrylate is generally 85%, the yield of methyl acrylate is generally 13.5%, and industrialization still cannot be realized at present.
Therefore, what is needed in the art is a clean synthesis process for realizing efficient green synthesis of unsaturated carboxylic acid esters including methyl acrylate by using industrial byproducts methyl acetate or other carboxylic acid esters as raw materials and adopting a safe, environment-friendly and nontoxic solid base catalyst.
Disclosure of Invention
In order to solve the problems in the prior art, the invention provides a method for preparing unsaturated carboxylic ester by utilizing multistage condensation reaction, a reaction system and an obtained product. Based on the mature process for preparing methyl acrylate by utilizing alpha-MMA (Lucite) by utilizing condensation reaction, the invention provides a novel catalyst for synthesizing unsaturated carboxylic acid esters including methyl acrylate by taking carboxylic acid esters including methyl acetate and formaldehyde as raw materials. The method also adopts a multi-stage condensation reaction inter-stage aldehyde supplementing dehydration technology, and solves the problems of low single-pass conversion of methyl acetate or other carboxylic esters and easy deactivation of the catalyst. The method of the invention improves the conversion rate of methyl acetate or other carboxylic esters, the selectivity of methyl acrylate or other unsaturated carboxylic esters and the stability of the catalyst, and makes the industrialized production of methyl acrylate or other carboxylic esters possible.
In order to achieve the above purpose, the present invention adopts the following scheme:
The invention provides a method for preparing unsaturated carboxylic ester by utilizing multistage condensation reaction, which comprises the steps of enabling raw materials of aldehyde compounds, alcohol compounds and saturated carboxylic ester compounds to undergo multistage condensation reaction in the presence of a catalyst to generate unsaturated carboxylic ester;
Adding supplementary material and optionally dewatering the material between the sections in the multistage condensation reaction; the supplemental raw materials include aldehydes and optionally alcohols.
In the invention, the multi-stage condensation reaction refers to that the condensation reaction is repeatedly carried out for a plurality of times, and before the condensation reaction is repeatedly carried out, supplementary raw materials are added and the materials among stages are optionally dehydrated; the supplemental raw materials include aldehydes and optionally alcohols.
In the present invention, the addition of an alcohol compound is advantageous in suppressing water produced by the reaction.
In the present invention, before repeating the condensation reaction, aldehyde compounds are added every time, and the addition of the raw materials is required between each stage of the multistage condensation reaction in order to further increase the conversion rate of the carboxylate raw materials. The purpose of the dehydration treatment is to protect the catalyst and reduce the negative reaction caused by water, and the dehydration treatment is not needed to be added between all sections. Thus, the present invention is an unordered requirement to add additional feedstock and optionally dehydration between stages of a multistage condensation reaction, and to add additional feedstock and optionally dehydration between the same stages.
In the method for producing an unsaturated carboxylic acid ester by a multistage condensation reaction according to the present invention, preferably,
The multistage condensation reaction is 2-10 stages; preferably 6 to 8 sections; and/or the number of the groups of groups,
The water content of the dehydrated material is less than 1000ppm; and/or the number of the groups of groups,
Before and/or after the dehydration treatment, carrying out heat exchange treatment on the materials between the sections;
Preferably, the temperature of the material after heat exchange treatment is 100-250 ℃ before the dehydration treatment, preferably 150-200 ℃; after the dehydration treatment, the temperature of the material after the heat exchange treatment is 300-450 ℃, preferably 300-400 ℃.
In the method for producing an unsaturated carboxylic acid ester by a multistage condensation reaction according to the present invention, preferably,
The aldehyde compound is selected from formaldehyde; and/or the number of the groups of groups,
The structure of the saturated acid ester is R 1COOCH3, the R 1 is selected from C1-C3 alkyl, and further preferably, the carboxylic acid ester compound is at least one selected from methyl acetate, methyl propionate or methyl n-butyrate; and/or the number of the groups of groups,
The alcohol compound is selected from methanol.
In the method for producing an unsaturated carboxylic acid ester by a multistage condensation reaction according to the present invention, preferably,
In the initial raw material for performing the first-stage condensation reaction, the molar ratio of the aldehyde compound to the carboxylate compound is 1:5-50, for example, may be 1:5, 1:10, 1:15, 1:20, 1:25, 1:30, 1:35, 1:40, 1:45, 1:50, and any range between any two of the above; preferably 1:10-20; and/or the number of the groups of groups,
The molar ratio of the alcohol compound to the carboxylate compound is 1:0.5-20, for example, the molar ratio can be 1:0.5, 1:1, 1:2, 1:4, 1:5, 1:10, 1:15, 1:20 and any range between any two of the above; preferably 1:0.5-10; and/or the number of the groups of groups,
In the multistage condensation reaction, the total liquid phase space velocity of the raw materials of each stage of condensation reaction is the same or different, and is respectively and independently 0.05h -1～5h-1, for example, 0.05, 0.1, 0.5, 0.8, 1,2, 3, 4 and 5 and any range between any two of the above numbers can be adopted; preferably 0.2h -1～1h-1; and/or the number of the groups of groups,
In the multistage condensation reaction, the temperature of each stage of condensation reaction is the same or different and is independently selected from 250-450 ℃, such as 250, 300, 350, 400, 450 ℃ and any range between any two of the above; preferably 300-400 ℃; and/or the number of the groups of groups,
In the multistage condensation reaction, the pressure of each stage of condensation reaction is the same or different and is independently selected from 0MPa to 1MPa, for example, 0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9 and 1MPa and any range between any two of the above; preferably 0MPa to 0.4MPa.
In the method for producing an unsaturated carboxylic acid ester by a multistage condensation reaction according to the present invention, preferably,
The molar ratio of the corresponding addition amount of the aldehyde compound in the supplementary raw material to the carboxylate compound in the initial raw material of the first-stage condensation reaction during each addition is 1:1-20, for example, the molar ratio can be 1:1, 1:2, 1:4, 1:5, 1:10, 1:15, 1:20 and any range between any two of the above numbers; preferably 1:5 to 10;
Preferably, the molar ratio of the aldehyde compound and the alcohol compound in the supplementary raw material is 1:0.2-20 when the supplementary raw material is supplemented, for example, the molar ratio can be 1:0.2, 1:0.5, 1:1, 1:2, 1:4, 1:5, 1:10, 1:15, 1:20 and any range between any two of the above; preferably 1:1 to 5.
In the dehydration treatment according to the present invention, preferably,
The dehydration treatment method is that dehydration is carried out through a dehydrating agent, preferably, the dehydrating agent is selected from anhydrous sulfate, further preferably, the dehydrating agent is selected from at least one of anhydrous copper sulfate, anhydrous ferric sulfate or anhydrous aluminum potassium sulfate; and/or the number of the groups of groups,
The temperature of the dehydration treatment is 100-250 ℃, preferably 150-200 ℃; and/or the number of the groups of groups,
The total space velocity of the material flowing through the dehydrating agent is 0.2 to 20h -1, preferably 0.5 to 5h -1.
In the catalyst according to the present invention, preferably,
The catalyst is a Cs-based solid base catalyst;
preferably, the preparation method of the Cs-based solid base catalyst comprises the following steps: and loading the soluble Cs salt and the placeholder on a carrier together, and roasting to obtain the Cs-based solid base catalyst.
Preferably, the method comprises the steps of,
The soluble Cs salt is selected from at least one of Cs 2CO3、CsNO3 and CsOH, csCl, csOAc; and/or the number of the groups of groups,
The placeholder is selected from soluble ammonium salts, preferably from at least one of (NH 4)2CO3 or NH 4 OAc), and/or,
The carrier is at least one selected from Al 2O3、SiO2 and active carbon; and/or the number of the groups of groups,
The soluble Cs salt and the placeholder form mixed solution to be loaded on the carrier together, preferably by an impregnation method;
More preferably, cs 2CO3 is co-supported on the support with (NH 4)2CO3 or CsOAc with NH 4 OAc) forming a mixture.
Preferably, the method comprises the steps of,
In the mixed solution, the mass concentration of the soluble Cs salt is 0.5-50%, preferably 2-20%; and/or the number of the groups of groups,
The mass concentration of the placer in the mixed solution is 0.2-30%, preferably 2-10%;
in the mixed solution, the mass ratio of the soluble Cs salt to the carrier is 1:2-200, preferably 1:5-50; and/or the number of the groups of groups,
The baking temperature is 250-800 ℃, such as 250, 300, 350, 400, 450, 500, 550, 600, 650, 700, 750, 800 ℃ and any range between any two of the above; preferably 350-600 ℃; and/or the number of the groups of groups,
The roasting time is 2-10 h, for example, 2, 3,4, 5, 6,7, 8, 9, 10h and any range between any two of the above; preferably 3 to 6 hours; more preferably, the drying treatment is performed at a temperature of 60 to 200 ℃ for a time of 2 to 24 hours before the firing.
In the catalyst according to the present invention, preferably,
In the Cs-based solid base catalyst, based on the mass of the Cs-based solid base catalyst being 100 percent,
The content of the Cs element is 0.2-60 wt%, for example, 0.2, 2, 4, 6, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60wt% and any range between any two of the above; preferably, the content of the Cs element is 2 to 20wt%.
The second object of the present invention is to provide an unsaturated carboxylic acid ester produced by the method for producing an unsaturated carboxylic acid ester by a multistage condensation reaction according to one of the objects of the present invention.
It is a further object of the present invention to provide a reaction system for producing an unsaturated carboxylic acid ester by a multistage condensation reaction, comprising a plurality of condensation reactors, a feed unit and optionally a dehydration unit connected; the feed unit and optionally the dehydration unit are located between the condensation reactors;
Preferably, the method for producing an unsaturated carboxylic acid ester by a multistage condensation reaction as described for achieving one of the objects of the present invention or the two unsaturated carboxylic acid esters as described for producing the object of the present invention, preferably, the unsaturated carboxylic acid ester is selected from methyl acrylate, methyl methacrylate or methyl 2-ethylacrylate.
In the reaction system according to the present invention, preferably,
The feed unit and optionally the dehydration unit are located between every two adjacent condensation reactors;
Preferably, the dehydration unit and the feed unit are both located between every two adjacent condensation reactors;
more preferably, the feed port of the dehydration unit is connected with the discharge port of the previous condensation reactor, and the discharge port of the dehydration unit is connected with the feed port of the next condensation reactor;
The discharge port of the feeding unit is communicated with the feed port of the dehydration unit or is communicated with a feed pipeline in front of the feed port of the dehydration unit.
Preferably, the method comprises the steps of,
When the reaction system comprises a dehydration unit, the reaction system further comprises a heat exchange unit;
Preferably, the number of the heat exchange units is more than two, and the heat exchange units are arranged between the feed inlet of the dehydration unit and the discharge outlet of the previous condensation reactor; a heat exchange unit is arranged between the discharge port of the dehydration unit and the feed port of the subsequent condensation reactor;
And a discharge port of the feeding unit is communicated with a feed port of the dehydration unit or is communicated with a feed pipeline behind the heat exchange unit in front of the feed port of the dehydration unit.
Preferably, the number of the heat exchange units is two, and the feed inlet of the dehydration unit is firstly connected with the heat exchange units and then connected with the discharge outlet of the previous condensation reactor through the heat exchange units; the discharge port of the dehydration unit is firstly connected with the heat exchange unit, and then is connected with the feed inlet of the subsequent condensation reactor through the heat exchange unit;
And a discharge hole of the feeding unit is communicated with a feed hole of the dehydration unit or a pipeline behind a discharge hole of the heat exchange unit before the feed hole of the dehydration unit.
The fourth object of the present invention is to provide a Cs-based solid base catalyst, based on 100% by mass of the Cs-based solid base catalyst,
The content of the Cs element is 0.2-60 wt%, preferably 2-20 wt%;
preference is given to catalysts in the process described as one of the objects of the invention.
The fifth purpose of the present invention is to provide a preparation method of the Cs-based solid base catalyst according to the fourth purpose of the present invention, comprising the following steps:
the preparation method of the Cs-based solid base catalyst comprises the following steps: and loading the soluble Cs salt and the placeholder on a carrier together, and roasting to obtain the Cs-based solid base catalyst.
In the preparation method of the Cs-based solid base catalyst according to the present invention, preferably,
The soluble Cs salt is selected from at least one of Cs 2CO3、CsNO3 and CsOH, csCl, csOAc; and/or the number of the groups of groups,
The placeholder is selected from soluble ammonium salts, preferably from at least one of (NH 4)2CO3 or NH 4 OAc), and/or,
The carrier is at least one selected from Al 2O3、SiO2 and active carbon; and/or the number of the groups of groups,
The soluble Cs salt and the placeholder forming mixture are co-supported on the support, preferably by impregnation.
In the preparation method of the Cs-based solid base catalyst according to the present invention, preferably,
In the mixed solution, the mass concentration of the soluble Cs salt is 0.5-50%, preferably 2-20%; and/or the number of the groups of groups,
The mass concentration of the placer in the mixed solution is 0.2-30%, preferably 2-10%;
in the mixed solution, the mass ratio of the soluble Cs salt to the carrier is 1:2-200, preferably 1:5-50; and/or the number of the groups of groups,
The roasting temperature is 250-800 ℃, preferably 350-600 ℃; and/or the number of the groups of groups,
The roasting time is 2-10 h, preferably 3-6 h;
More preferably, the drying treatment is performed at a temperature of 60 to 200 ℃ for a time of 2 to 24 hours before the firing.
The invention provides a multistage condensation reaction process, wherein the reaction of methyl acetate or other carboxylic acid esters and formaldehyde is required to be carried out under the condition of high ester-to-aldehyde ratio, so that the conversion rate of the methyl acetate or other carboxylic acid esters is limited. The multi-stage condensation reaction is adopted and the process of feeding materials among the stages is adopted, but water generated by the multi-stage reaction is accumulated in the system all the time, so that higher requirements are put on the hydrothermal stability of a catalyst at the later stage, the conversion rate and the selectivity of the reaction are influenced by the existence of water, and the long-period stability of the catalyst is seriously influenced, so that the water is removed through dehydration treatment in the multi-stage condensation reaction process.
In the preparation process of the catalyst, the soluble Cs salt is easy to polymerize, so that the dispersibility of Cs element in the catalyst is poor; meanwhile, during roasting, the soluble ammonium salt can be decomposed, so that the use effect of the catalyst is not affected. Therefore, the invention adopts the mixed impregnation of the soluble Cs salt and the placeholder for preparing the catalyst, and then the placeholder is decomposed by in-situ programmed temperature roasting in the reactor, compared with the catalyst prepared by directly adopting the soluble Cs salt (such as Cs 2CO3、CsNO3 and other Cs salt), the dispersibility of the active site in the catalyst can be obviously improved, and thus the catalytic activity is obviously improved.
The endpoints of the ranges and any values disclosed in the present invention are not limited to the precise range or value, and the range or value should be understood to include values close to the range or value. For numerical ranges, one or more new numerical ranges may be found between the endpoints of each range, between the endpoint of each range and the individual point value, and between the individual point value, in combination with each other, and are to be considered as specifically disclosed herein. In the following, the individual technical solutions can in principle be combined with one another to give new technical solutions, which should also be regarded as specifically disclosed herein.
Compared with the prior art, the invention has at least the following advantages:
The invention adopts the multi-stage condensation reaction inter-stage aldehyde supplementing dehydration technology, and solves the problems of low single-pass conversion of methyl acetate or other carboxylic esters and easy deactivation of the catalyst. The method of the invention improves the conversion rate of methyl acetate or other carboxylic acid esters, the selectivity of methyl acrylate or other unsaturated carboxylic acid esters and the stability of the catalyst, and makes the industrialized production of methyl acrylate or other unsaturated carboxylic acid esters possible.
The invention synthesizes a new catalyst, and the catalyst has high dispersion degree and catalytic activity of active components.
Drawings
FIG. 1 is a schematic diagram of a reaction system for preparing methyl acrylate according to example 1 of the present invention;
FIG. 2 is a schematic diagram of a reaction system for preparing methyl acrylate according to example 3 of the present invention;
FIG. 3 shows the CO 2 -TPD results for the catalyst prepared by impregnating the Cs salt of preparation example 1 with the placeholder in accordance with the present invention and the catalyst prepared by impregnating the pure Cs salt of comparative example 1.
Reference numerals illustrate:
1-one-stage condensation reactor, 2-feeding unit, 3-dehydration unit, 4-first heat exchange unit, 5-second heat exchange unit, 6-two-stage condensation reactor.
Detailed Description
The present invention is described in detail below with reference to the specific drawings and examples, and it is necessary to point out that the following examples are given for further illustration of the present invention only and are not to be construed as limiting the scope of the present invention, since numerous insubstantial modifications and adaptations of the invention to those skilled in the art will still fall within the scope of the present invention.
In addition, the specific features described in the following embodiments may be combined in any suitable manner without contradiction. The various possible combinations of the invention are not described in detail in order to avoid unnecessary repetition.
In addition, any combination of the various embodiments of the present invention can be made, so long as the concept of the present invention is not deviated, and the technical solution formed thereby is a part of the original disclosure of the present specification, and also falls within the protection scope of the present invention.
The raw materials used in examples and comparative examples, if not particularly limited, are all as disclosed in the prior art, and are, for example, available directly or prepared according to the preparation methods disclosed in the prior art.
CO 2 -TPD test method:
Test instrument: us Micromeritics AutoChem II 2920.
Test conditions: and heating the nitrogen atmosphere to 500 ℃, staying for 4 hours, desorbing water and carbon dioxide in the air adsorbed on the surface, cooling to room temperature, starting to adsorb the carbon dioxide, programming to 550 ℃, and detecting the content of the carbon dioxide at the outlet.
[ PREPARATION EXAMPLE 1]
Taking 100 g of solution (containing 12g of cesium carbonate and 6 g of ammonium carbonate) of cesium carbonate, ammonium carbonate and water after mixing; 60 g of silica microspheres (microsphere diameter 2.5mm, BET average pore diameter 22nm, BET pore volume 1.1 ml/g), and then drying at 90℃for 24 hours, and calcining at 500℃in an air atmosphere for 5 hours to obtain a catalyst finished product, wherein the mass content of Cs is 16%.
[ PREPARATION EXAMPLE 2]
Taking 100g of solution (containing 2 g of cesium carbonate and 2 g of ammonium carbonate) obtained by mixing cesium carbonate, ammonium carbonate and water; 5 g of silica microspheres (microsphere diameter: 2.5mm, BET average pore diameter: 22nm, BET pore volume: 1.1 ml/g), and then dried at 200℃for 2 hours, and calcined at 600℃in an air atmosphere for 3 hours to obtain a catalyst finished product, wherein the mass content of Cs was 32%.
[ PREPARATION EXAMPLE 3]
Taking 100 g of solution (containing 20 g of cesium carbonate and 10g of ammonium carbonate) obtained by mixing cesium carbonate, ammonium carbonate and water; 1000 g of silica microspheres (microsphere diameter 2.5mm, BET average pore diameter 22nm, BET pore volume 1.1 ml/g), standing for 24 hours, drying at 60 ℃ for 24 hours, and calcining at 350 ℃ and air atmosphere for 6 hours to obtain a catalyst finished product, wherein the mass content of Cs is 2%.
[ PREPARATION EXAMPLE 4]
Taking 100g of solution (15 g of cesium carbonate and 8 g of ammonium carbonate) of cesium carbonate, ammonium carbonate and water after mixing; 150 g of silica microspheres (microsphere diameter: 2.5mm, BET average pore diameter: 22nm, BET pore volume: 1.1 ml/g), were mixed, allowed to stand for 24 hours, then dried at 120℃for 5 hours, and calcined at 500℃in an air atmosphere for 4 hours to obtain a catalyst finished product in which the mass content of Cs was 8%.
[ PREPARATION EXAMPLE 5]
Taking 100 g of a solution of cesium carbonate, NH 4 OAc mixed with water (30 g of cesium carbonate, 20 g of NH 4 OAc); 600 g of Al 2O3 microspheres (microsphere diameter 2.5mm, BET average pore diameter 16nm, BET pore volume 0.9 ml/g) were mixed, left stand for 24 hours, then dried at 120 ℃ for 5 hours, and calcined at 500 ℃ in an air atmosphere for 4 hours to obtain a catalyst finished product in which the mass content of Cs is 4%.
Comparative example 1
Taking 100 g of a solution (containing 12 g of cesium carbonate) of cesium carbonate mixed with water; 60 g of silica microspheres (microsphere diameter 2.5mm, BET average pore diameter 22nm, BET pore volume 1.1 ml/g), and then drying at 90℃for 24 hours, and calcining at 500℃in an air atmosphere for 5 hours to obtain a catalyst finished product, wherein the mass content of Cs is 16%.
Comparative example 2
Taking 100 g of a solution (containing 12 g of cesium carbonate) of cesium carbonate mixed with water; 60 g of silica microspheres (microsphere diameter 2.5mm, BET method average pore diameter 22nm, BET method pore volume 1.1 ml/g), standing for 24 hours, immersing into 100 g (containing 8 g of ammonium carbonate) of solution of mixed ammonium carbonate and water, standing for 24 hours, drying at 90 ℃ for 24 hours, and roasting at 500 ℃ and air atmosphere for 5 hours to obtain a catalyst finished product, wherein the mass content of Cs is 16%.
The catalysts prepared in preparation example 1 and comparative example 1 were subjected to CO 2 -TPD test, and the results are shown in FIG. 3. Comparing the CO 2 -TPD results of the two catalysts, the results show that under the condition of the same Cs load, the peak positions of the two catalysts are approximately the same, which indicates that the alkali strength of the surface active sites of the catalysts is similar, and can further indicate that the placeholder is decomposed and run away after roasting, namely, the placeholder in the catalyst obtained by mixing and impregnating the Cs salt and the placeholder is volatilized and decomposed; and the CO2 absorption peak area of the catalyst obtained by adopting the mixed impregnation of the Cs salt and the placeholder is obviously higher than that of the catalyst obtained by adopting the simple impregnation of the Cs salt, and the peak area is 12 percent higher, which shows that the mixed impregnation can improve the dispersion of active species, thereby improving the number of active centers on the surface of the catalyst.
[ Example 1]
As shown in FIG. 1, the reaction system for preparing unsaturated carboxylic ester by utilizing multistage condensation reaction comprises 2 connected condensation reactors, namely a first-stage condensation reactor 1, a second-stage condensation reactor 6 and a feeding unit 2; the feeding unit 2 is positioned between the first-stage condensation reactor 1 and the second-stage condensation reactor 6; the feed inlet of the feeding unit 2 is communicated with a pipeline between the first-stage condensation reactor 1 and the second-stage condensation reactor 6.
The methyl acrylate is prepared by adopting the reaction system, and specifically comprises the following steps: respectively loading 5g of the catalyst prepared in preparation example 1 into a first-stage condensation reactor (with an inner diameter of 16mm and a length of 1500 mm) and a second-stage condensation reactor (with an inner diameter of 16mm and a length of 1500 mm), replacing the catalyst with N 2 for three times, then raising the temperature of the two reactors to 380 ℃, regulating the pressure to 0.2MPa, and introducing reaction raw materials into the first-stage condensation reactor and the second-stage condensation reactor according to a total mass space velocity of methyl acetate, formaldehyde and methanol of 1h -1 (the composition of the reaction raw materials is calculated according to a mole ratio, the mole ratio of formaldehyde to methyl acetate is 1:5, the mole ratio of methanol to methyl acetate is 1:4), discharging the first-stage condensation reactor after the condensation reaction, and then flowing the first-stage condensation reactor into a pipeline between a feeding port of a feeding unit and the first-stage condensation reactor and the second-stage condensation reactor for feeding, wherein the composition of the feeding material is calculated according to a mole ratio, and the mole ratio of formaldehyde to methanol is 1:1; the molar ratio of the formaldehyde to the carboxylate compound in the initial raw material of the first stage condensation reaction is 1:8); the total mass space velocity of the two-stage condensation reactor is 0.2h -1, sampling is carried out, internal standard toluene is added, the content of each component in the reaction mixture is measured by gas chromatography, the conversion rate of methyl acetate is calculated to be 18.2%, the selectivity of methyl acrylate is calculated to be 91.3%, after 10 days of operation, the conversion rate of methyl acetate is 15.7%, and the selectivity of methyl acrylate is calculated to be 92.4%.
[ Example 2]
A reaction system for preparing unsaturated carboxylic ester by utilizing multistage condensation reaction comprises 2 connected condensation reactors, namely a first-stage condensation reactor 1 and a second-stage condensation reactor 6, a feeding unit 2 and a dehydration unit 3; the dehydration unit 3 and the feeding unit 2 are positioned between 2 condensation reactors; the feed inlet of the dehydration unit 3 is connected with the discharge outlet of the first-stage condensation reactor 1, and the discharge outlet of the dehydration unit 3 is connected with the feed inlet of the second-stage condensation reactor 6;
The discharge port of the feeding unit 2 is communicated with a pipeline between the feed port of the dehydration unit 2 and the discharge port of the first-stage condensation reactor 1.
The methyl acrylate is prepared by adopting the reaction system, and specifically comprises the following steps: respectively loading 5 g of the catalyst prepared in preparation example 1 into a first-stage condensation reactor (with an inner diameter of 16mm and a length of 1500 mm) and a second-stage condensation reactor (with an inner diameter of 16mm and a length of 1500 mm), replacing the catalyst with N 2 for three times, then raising the temperature of the two reactors to 380 ℃, regulating the pressure to 0.2MPa, and introducing reaction raw materials into the first-stage condensation reactor and the second-stage condensation reactor according to a total mass space velocity of methyl acetate, formaldehyde and methanol of 1h -1 (the composition of the reaction raw materials is calculated according to a mole ratio, the mole ratio of formaldehyde to methyl acetate is 1:5, the mole ratio of methanol to methyl acetate is 1:4), discharging the first-stage condensation reactor after the condensation reaction, and then flowing the first-stage condensation reactor into a pipeline between a feeding port of a feeding unit and the first-stage condensation reactor and the second-stage condensation reactor for feeding, wherein the composition of the feeding material is calculated according to a mole ratio, and the mole ratio of formaldehyde to methanol is 1:1; the molar ratio of the formaldehyde to the carboxylate compound in the initial raw material of the first stage condensation reaction is 1:8); the dehydration unit is used for dehydrating through a dehydrating agent, the dehydrating agent is selected from anhydrous copper sulfate, the temperature of the dehydration treatment is 150 ℃, the total space velocity of materials flowing through the dehydrating agent is 1h -1, the total mass space velocity of a two-stage condensation reactor is 0.2h -1, sampling is carried out, internal standard toluene is added, the content of each component in a reaction mixture is measured through gas chromatography, the conversion rate of methyl acetate is calculated to be 19.7%, the selectivity of methyl acrylate is calculated to be 93.6%, and after 10 days of operation, the conversion rate of methyl acetate is 18.1%, and the selectivity of methyl acrylate is calculated to be 94.5%.
[ Example 3]
As shown in FIG. 2, the reaction system for preparing unsaturated carboxylic ester by multi-stage condensation reaction of the invention comprises 2 connected condensation reactors, namely a first-stage condensation reactor 1 and a second-stage condensation reactor 6, a feeding unit 2, a dehydration unit 3 and 2 heat exchange units (namely a first heat exchange unit 4 and a second heat exchange unit 5); the dehydration unit 3, the 2 heat exchange units and the feeding unit 2 are positioned between the 2 condensation reactors;
The feed inlet of the dehydration unit 3 is firstly connected with the first heat exchange unit 4, and then is connected with the discharge outlet of the first-stage condensation reactor 1 through the first heat exchange unit 4; the discharge port of the dehydration unit 3 is firstly connected with a second heat exchange unit 5, and then is connected with the feed port of the two-stage condensation reactor 6 through the second heat exchange unit 5; the discharge port of the feeding unit 2 is communicated with a pipeline behind the discharge port of the first heat exchange unit 4 before the feed port of the dewatering unit 3.
The methyl acrylate is prepared by adopting the reaction system, and specifically comprises the following steps: respectively loading 5g of the catalyst prepared in preparation example 1 into a first-stage condensation reactor (with the inner diameter of 16mm and the length of 1500 mm) and a second-stage condensation reactor (with the inner diameter of 16mm and the length of 1500 mm), replacing the catalyst with N 2 for three times, then raising the temperature of the two reactors to 380 ℃, regulating the pressure to 0.2MPa, and adopting a method for preparing methyl acrylate by multistage condensation reaction, introducing reaction raw materials (the composition of the reaction raw materials is calculated by the mole ratio, the mole ratio of formaldehyde to methyl acetate is 1:5, and the mole ratio of methanol to methyl acetate is 1:4) into the reaction raw materials by using the total mass airspeed of methyl acetate, formaldehyde and methanol as 1h -1, discharging the reaction raw materials from the first-stage condensation reactor after the condensation reaction, and sequentially passing through a first heat exchange unit, a dehydration unit and a second heat exchange unit to the second-stage condensation reactor, wherein a feed inlet of a feed supplementing unit is communicated with a pipeline between the dehydration unit and the first heat exchange unit, and feeding the first heat exchange unit; the temperature after heat exchange of the first heat exchange unit is 180 ℃, the dehydration unit is used for dehydrating through a dehydrating agent, the dehydrating agent is selected from anhydrous copper sulfate, the temperature of dehydration treatment is 150 ℃, the total airspeed of materials flowing through the dehydrating agent is 1h -1, the composition of supplementary materials of the material supplementing unit is calculated according to the mole ratio, and the mole ratio of formaldehyde to methanol is 1:1; the molar ratio of formaldehyde to carboxylate compound in the initial raw material of the first stage condensation reaction is 1:8), the temperature after heat exchange of the second heat exchange unit is 380 ℃, the total mass space velocity of the second stage condensation reactor is 0.2h -1, sampling is carried out, the content of each component in the reaction mixture is measured by gas chromatography by adding internal standard toluene, the conversion rate of methyl acetate is calculated to be 22.6%, the selectivity of methyl acrylate is 94.5%, the conversion rate of methyl acetate is 21.9% after 10 days of operation, and the selectivity of methyl acrylate is 95.2%.
[ Example 4]
In comparison with example 1, the number of condensation reactors was 6 and the number of feed units was 5, i.e. connected in accordance with the connection of FIG. 1.
The methyl acrylate is prepared by adopting the reaction system, and specifically comprises the following steps: respectively loading 5g of the catalyst prepared in preparation example 1 into a first-stage condensation reactor (with an inner diameter of 16mm and a length of 1500 mm) and a second-stage condensation reactor (with an inner diameter of 16mm and a length of 1500 mm), replacing the catalyst with N 2 for three times, then raising the temperature of the two reactors to 380 ℃, regulating the pressure to 0.2MPa, and introducing reaction raw materials into the first-stage condensation reactor and the second-stage condensation reactor according to a total mass space velocity of methyl acetate, formaldehyde and methanol of 1h -1 (the composition of the reaction raw materials is calculated according to a mole ratio, the mole ratio of formaldehyde to methyl acetate is 1:5, the mole ratio of methanol to methyl acetate is 1:4), discharging the first-stage condensation reactor after the condensation reaction, and then flowing the first-stage condensation reactor into a pipeline between a feeding port of a feeding unit and the first-stage condensation reactor and the second-stage condensation reactor for feeding, wherein the composition of the feeding material is calculated according to a mole ratio, and the mole ratio of formaldehyde to methanol is 1:1; the molar ratio of the formaldehyde to the carboxylate compound in the initial raw material of the first stage condensation reaction is 1:8); the total mass space velocity of the two-stage condensation reactor is 0.2h -1, the reaction is repeatedly carried out in sequence under the same conditions as the two-stage condensation reactor until reaching the six-stage condensation reactor, sampling is carried out, internal standard toluene is added, the content of each component in the reaction mixture is measured by gas chromatography, the conversion rate of methyl acetate is calculated to be 24.5%, the selectivity of methyl acrylate is 92.7%, and after 10 days of operation, the conversion rate of methyl acetate is 20.2%, and the selectivity of methyl acrylate is 93.6%.
[ Example 5]
A reaction system for preparing unsaturated carboxylic ester by utilizing multistage condensation reaction comprises 2 connected condensation reactors, namely a first-stage condensation reactor 1 and a second-stage condensation reactor 6, a feeding unit 2 and a dehydration unit 3; the dehydration unit 3 and the feeding unit 2 are positioned between 2 condensation reactors; the feed inlet of the dehydration unit 3 is connected with the discharge outlet of the first-stage condensation reactor, and the discharge outlet of the dehydration unit is connected with the feed inlet of the second-stage condensation reactor;
And a discharge hole of the feeding unit is communicated with a pipeline between a feed hole of the dehydration unit and a discharge hole of the first-stage condensation reactor.
The methyl acrylate is prepared by adopting the reaction system, and specifically comprises the following steps: 5g of the catalyst prepared in preparation example 2 is put into a first-stage condensation reactor (with the inner diameter of 16mm and the length of 1500 mm) and a second-stage condensation reactor (with the inner diameter of 16mm and the length of 1500 mm), after three times of replacement by N 2, the temperature of the two reactors is raised to 300 ℃, the pressure is regulated to 0.2MPa, the methyl acrylate is prepared by using a multi-stage condensation reaction method, reaction raw materials are introduced according to the total mass airspeed of methyl acetate, formaldehyde and methanol of 0.2h -1 (the composition of the reaction raw materials is calculated according to the mole ratio, the formaldehyde and the methyl acetate are 1:10; the methanol and the methyl acetate are 1:0.5), after the condensation reaction of the first-stage condensation reactor, the material is discharged from the first-stage condensation reactor, then flows into a dehydration unit, and flows into the second-stage condensation reactor from the dehydration unit, wherein a pipeline between a material outlet of the material supplementing unit and a material outlet of the first-stage condensation reactor is communicated, and the composition of the supplementary materials is calculated according to the mole ratio, and the formaldehyde and the methanol is 1:3; the molar ratio of the formaldehyde to the carboxylate compound in the initial raw material of the first stage condensation reaction is 1:5); the dehydration unit is used for dehydrating through a dehydrating agent, the dehydrating agent is selected from anhydrous sulfate, the temperature of the dehydration treatment is 150 ℃, the total space velocity of materials flowing through the dehydrating agent is 0.2h -1, the total mass space velocity of a two-stage condensation reactor is 0.2h -1, sampling is carried out, internal standard toluene is added, the content of each component in a reaction mixture is measured through gas chromatography, the conversion rate of methyl acetate is calculated to be 15.1%, the selectivity of methyl acrylate is calculated to be 92.4%, and after 10 days of operation, the conversion rate of methyl acetate is calculated to be 13.2%, and the selectivity of methyl acrylate is calculated to be 92.8%.
In the invention, the conversion rate and selectivity of methyl acetate are greatly related to the ratio of raw materials and the reaction temperature, and generally the lower the reaction temperature is, the lower the conversion rate and selectivity of methyl acetate are.
[ Example 6]
As shown in FIG. 2, the reaction system for preparing unsaturated carboxylic ester by multi-stage condensation reaction of the invention comprises 2 connected condensation reactors, namely a first-stage condensation reactor 1 and a second-stage condensation reactor 6, a feeding unit 2, a dehydration unit and 2 heat exchange units; the dehydration unit, the 2 heat exchange units and the feeding unit are positioned among the 2 condensation reactors;
the feeding port of the dehydration unit is connected with the first heat exchange unit firstly and then is connected with the discharging port of the first-stage condensation reactor through the first heat exchange unit; the discharge port of the dehydration unit is connected with the second heat exchange unit firstly, and then is connected with the feed port of the two-stage condensation reactor through the second heat exchange unit; and a discharge port of the feeding unit is communicated with a pipeline behind a discharge port of the first heat exchange unit before a feed port of the dehydration unit.
The methyl acrylate is prepared by adopting the reaction system, and specifically comprises the following steps: 5g of the catalyst prepared in preparation example 3 is put into a first-stage condensation reactor (with the inner diameter of 16mm and the length of 1500 mm) and a second-stage condensation reactor (with the inner diameter of 16mm and the length of 1500 mm), after the catalyst is replaced by N 2 for three times, the temperature of the two reactors is raised to 300 ℃, the pressure is regulated to 0.4MPa, and the methyl acrylate is prepared by using a multi-stage condensation reaction method, reaction raw materials are introduced into the reaction raw materials (the composition of the reaction raw materials is calculated according to the mole ratio, formaldehyde and methyl acetate are 1:20, methanol and methyl acetate are 1:10) according to the total mass airspeed of 1h -1 of methyl acetate, the first-stage condensation reactor is subjected to condensation reaction, then the material is discharged from the first-stage condensation reactor, and then flows into the second-stage condensation reactor through a first heat exchange unit, a dehydration unit and a second heat exchange unit in sequence, wherein a feeding port of a feeding unit is communicated with a pipeline between the dehydration unit and the first heat exchange unit for feeding; the temperature after heat exchange of the first heat exchange unit is 210 ℃, the dehydration unit is used for dehydrating through a dehydrating agent, the dehydrating agent is selected from anhydrous sulfate, the temperature of dehydration treatment is 200 ℃, the total airspeed of materials flowing through the dehydrating agent is 5h -1, the composition of supplementary materials is calculated according to the molar ratio, and the formaldehyde and the methanol are 1:5; the molar ratio of the formaldehyde to the carboxylate compound in the initial raw material of the first stage condensation reaction is 1:10); the temperature after heat exchange of the first heat exchange unit is 300 ℃, the total mass space velocity of the two-stage condensation reactor is 1h -1, sampling is carried out, the content of each component in the reaction mixture is measured by gas chromatography by adding internal standard toluene, the conversion rate of methyl acetate is calculated to be 14.4%, the selectivity of methyl acrylate is calculated to be 94.3%, and after 10 days of operation, the conversion rate of methyl acetate is 13.9%, and the selectivity of methyl acrylate is calculated to be 94.7%. Example 6 the somewhat worse conversion of methyl acetate compared to example 1 is that mainly the lower condensation reaction temperature leads to a lower conversion.
[ Example 7]
As shown in FIG. 2, the reaction system for preparing methyl methacrylate by utilizing the multistage condensation reaction comprises 2 condensation reactors, namely a first-stage condensation reactor 1 and a second-stage condensation reactor 6, a feeding unit 2 and a dehydration unit, which are connected; the dehydration unit and the feeding unit are positioned between 2 condensation reactors;
And a discharge hole of the feeding unit is communicated with a pipeline between a feed hole of the dehydration unit and a discharge hole of the first-stage condensation reactor.
The methyl methacrylate is prepared by adopting the reaction system, and specifically comprises the following steps: 5g of the catalyst prepared in preparation example 4 is filled into a first-stage condensation reactor (with the inner diameter of 16mm and the length of 1500 mm) and a second-stage condensation reactor (with the inner diameter of 16mm and the length of 1500 mm), after the catalyst is replaced by N 2 for three times, the temperature of the two reactors is raised to 360 ℃, the pressure is regulated to 0.3MPa, the methyl methacrylate is prepared by using a multi-stage condensation reaction method, reaction raw materials are introduced according to the total mass space velocity of methyl propionate, formaldehyde and methanol of 0.5h -1 (the composition of the reaction raw materials is calculated according to the molar ratio, the formaldehyde and the methyl propionate are 1:15; the methanol and the methyl acetate are 1:6), after the condensation reaction of the first-stage condensation reactor, the material is discharged from the first-stage condensation reactor, then flows into a dehydration unit, and flows into the second-stage condensation reactor from the dehydration unit, wherein a pipeline between a material outlet of the material supplementing unit and a material outlet of the first-stage condensation reactor is communicated, and the material supplementing the composition of the material is calculated according to the molar ratio, the formaldehyde and the methanol is 1:2; the molar ratio of the formaldehyde to the carboxylate compound in the initial raw material of the first stage condensation reaction is 1:6); the dehydration unit is used for dehydrating through a dehydrating agent, the dehydrating agent is selected from anhydrous sulfate, the temperature of dehydration treatment is 180 ℃, the total space velocity of materials flowing through the dehydrating agent is 2h -1, the total mass space velocity of a two-stage condensation reactor is 0.5h -1, sampling is carried out, internal standard toluene is added, the content of each component in a reaction mixture is measured through gas chromatography, the conversion rate of methyl propionate is calculated to be 26.3%, the selectivity of methyl methacrylate is calculated to be 93.5%, the conversion rate of methyl acetate is calculated to be 25.9% after 10 days of operation, and the selectivity of methyl acrylate is calculated to be 94.4%.
[ Example 8]
The invention relates to a reaction system for preparing 2-ethyl methyl acrylate by utilizing a multistage condensation reaction, which comprises 6 condensation reactors, namely a first-stage condensation reactor and a second-stage condensation reactor which are connected, wherein the six condensation reactors, a feeding unit, a dehydration unit and 12 heat exchange units are arranged; the dehydration unit, the 2 heat exchange units and the feeding unit are arranged between 2 condensation reactors in a group; the feed inlet of the dehydration unit is connected with the discharge outlet of the first-stage condensation reactor, and the discharge outlet of the dehydration unit is connected with the feed inlet of the second-stage condensation reactor;
the feeding port of the dehydration unit is connected with the first heat exchange unit firstly and then is connected with the discharging port of the first-stage condensation reactor through the first heat exchange unit; the discharge port of the dehydration unit is connected with the second heat exchange unit firstly, and then is connected with the feed port of the two-stage condensation reactor through the second heat exchange unit; and a discharge port of the feeding unit is communicated with a pipeline behind a discharge port of the first heat exchange unit before a feed port of the dehydration unit.
The methyl acrylate is prepared by adopting the reaction system, and specifically comprises the following steps: 5g of the catalyst prepared in preparation example 5 is put into a first-stage condensation reactor (with the inner diameter of 16mm and the length of 1500 mm) and a second-stage condensation reactor (with the inner diameter of 16mm and the length of 1500 mm), after three times of replacement by N 2, the temperature of the two reactors is raised to 450 ℃, the pressure is regulated to 0.6MPa, and the reaction raw materials are introduced into the first-stage condensation reactor by using a method of preparing 2-ethyl methyl acrylate through multistage condensation reaction, wherein the total mass space velocity of methyl butyrate, formaldehyde and methanol is 3h -1 (the composition of the reaction raw materials is calculated by mole ratio, the formaldehyde and methyl acetate are 1:30; the methanol and the methyl N-butyrate are 1:15), after the condensation reaction of the first-stage condensation reactor, the first-stage condensation reactor is discharged, and then flows into the second-stage condensation reactor through a first heat exchange unit, a dehydration unit and a second heat exchange unit in sequence, and a pipeline between a feed inlet of a feed supplementing unit and the dehydration unit is communicated with the first heat exchange unit, so as to supplement; the temperature after heat exchange of the first heat exchange unit is 250 ℃, the dehydration unit is used for dehydrating through a dehydrating agent, the dehydrating agent is selected from anhydrous sulfate, the temperature of dehydration treatment is 240 ℃, the total airspeed of materials flowing through the dehydrating agent is 3h -1, the composition of supplementary materials is calculated according to the mole ratio, and the mole ratio of formaldehyde to methanol is 1:10; the molar ratio of the formaldehyde to the carboxylate compound in the initial raw material of the first stage condensation reaction is 1:20); the temperature after heat exchange of the second heat exchange unit is 450 ℃, the total mass space velocity of the two-stage condensation reactor is 3h -1, the other condensation reactions between stages are carried out according to the same reaction parameters, finally sampling is carried out, internal standard toluene is added, the content of each component in the reaction mixture is measured by gas chromatography, the conversion rate of methyl n-butyrate is calculated to be 31.3%, the selectivity of 2-ethyl methyl acrylate is 82.4%, and after 10 days of operation, the conversion rate of methyl acetate is 27.2%, and the selectivity of methyl acrylate is 84.1%.
[ Example 9]
The difference compared with example 1 is that the catalyst prepared in comparative example 1 is adopted, the rest reaction conditions are the same, sampling is carried out, internal standard toluene is added, the content of each component in the reaction mixture is measured by gas chromatography, the conversion rate of methyl acetate is calculated to be 14.5%, the selectivity of methyl acrylate is calculated to be 88.7%, and after 10 days of operation, the conversion rate of methyl acetate is 11.3%, and the selectivity of methyl acrylate is calculated to be 89.2%.
[ Example 10]
The difference compared with example 1 is that the catalyst prepared in comparative example 2 is adopted, the rest reaction conditions are the same, sampling is carried out, internal standard toluene is added, the content of each component in the reaction mixture is measured by gas chromatography, the conversion rate of methyl acetate is calculated to be 12.3%, the selectivity of methyl acrylate is calculated to be 89.6%, and after 10 days of operation, the conversion rate of methyl acetate is calculated to be 10.4%, and the selectivity of methyl acrylate is calculated to be 90.5%.
Comparison of the results of example 1, example 9 and example 10 shows that when methyl acrylate is prepared by the same reaction system, the conversion rate and selectivity of methyl acrylate are affected by different catalysts; the catalyst prepared in example 1 by the mixed impregnation method of the soluble Cs salt and the placeholder has better dispersibility of the active components, better catalytic activity and better conversion rate and selectivity of the corresponding methyl acrylate.
[ Comparative example 3]
It was different from example 1 in that the catalyst prepared in comparative example 1 was used, and the reaction system for producing methyl acrylate described in fig. 1 was used, but the reaction system did not contain a feeding unit; the system is adopted to prepare methyl acrylate, no feed supplement is needed in the preparation process, the rest reaction conditions are the same, sampling is carried out, internal standard toluene is added, the content of each component in the reaction mixture is measured by gas chromatography, the conversion rate of methyl acetate is calculated to be 11.3%, the selectivity of methyl acrylate is calculated to be 88.1%, after 10 days of operation, the conversion rate of methyl acetate is calculated to be 9.8%, and the selectivity of methyl acrylate is calculated to be 87.4%.
[ Comparative example 4]
It differs from example 1 in that it uses the catalyst prepared in comparative example 1, but the reaction system contains only one stage of condensation reactor; the system is adopted to prepare methyl acrylate, and no feed supplement and no second-stage condensation reaction are generated in the preparation process; the other reaction conditions are the same, sampling is carried out, internal standard toluene is added, the content of each component in the reaction mixture is measured by gas chromatography, the conversion rate of methyl acetate is calculated to be 9.5%, the selectivity of methyl acrylate is calculated to be 90.2%, after 10 days of operation, the conversion rate of methyl acetate is calculated to be 6.1%, and the selectivity of methyl acrylate is calculated to be 91.1%.
The invention has been described in detail in connection with the specific embodiments and exemplary examples thereof, but such description is not to be construed as limiting the invention. It will be understood by those skilled in the art that various equivalent substitutions, modifications or improvements may be made to the technical solution of the present invention and its embodiments without departing from the spirit and scope of the present invention, and these fall within the scope of the present invention. The scope of the invention is defined by the appended claims.
Claims (15)
1. A method for preparing unsaturated carboxylic ester by multi-stage condensation reaction comprises subjecting raw materials of aldehyde compound, alcohol compound and saturated carboxylic ester compound to multi-stage condensation reaction in the presence of catalyst to obtain unsaturated carboxylic ester;
Adding supplementary material and optionally dewatering the material between the sections in the multistage condensation reaction; the supplemental raw materials include aldehydes and optionally alcohols.
2. The method according to claim 1, characterized in that:
the multistage condensation reaction is 2-10 stages; preferably 6 to 8 sections; and/or the number of the groups of groups,
The water content of the dehydrated material is less than 1000ppm; and/or the number of the groups of groups,
Carrying out heat exchange treatment on the materials among the sections before and/or after the dehydration treatment, wherein the temperature of the materials after the heat exchange treatment is preferably 100-250 ℃ before the dehydration treatment, and is preferably 150-200 ℃; after the dehydration treatment, the temperature of the material after the heat exchange treatment is 300-450 ℃, preferably 300-400 ℃.
3. The method according to claim 1, characterized in that:
The aldehyde compound is selected from formaldehyde; and/or the number of the groups of groups,
The structure of the saturated acid ester compound is R 1COOCH3, the R 1 is selected from C1-C3 alkyl, and further preferably, the carboxylic acid ester compound is at least one selected from methyl acetate, methyl propionate or methyl n-butyrate; and/or the number of the groups of groups,
The alcohol compound is selected from methanol.
4. The method according to claim 1, characterized in that:
in the initial raw material for the first stage condensation reaction, the molar ratio of the aldehyde compound to the carboxylic ester compound is 1:5-50, preferably 1:10-20; and/or the number of the groups of groups,
The molar ratio of the alcohol compound to the carboxylic ester compound is 1:0.5-20, preferably 1:0.5-10; and/or the number of the groups of groups,
In the multistage condensation reaction, the total liquid phase space velocity of the raw materials of each stage of condensation reaction is the same or different, and is respectively and independently 0.05h -1～5h-1, preferably 0.2h -1～1h-1; and/or the number of the groups of groups,
In the multistage condensation reaction, the temperature of each stage of condensation reaction is the same or different and is independently selected from 250-450 ℃, preferably 300-400 ℃; and/or the number of the groups of groups,
In the multistage condensation reaction, the pressure of each stage of condensation reaction is the same or different and is independently selected from 0MPa to 1MPa, preferably 0MPa to 0.4MPa.
5. The method according to claim 1, characterized in that:
The molar ratio of the corresponding addition amount of the aldehyde compound in the supplementary raw material to the carboxylate compound in the initial raw material of the first-stage condensation reaction is 1:1-20, preferably 1:5-10;
Preferably, the molar ratio of the aldehyde compound to the alcohol compound in the supplementary raw material is 1:0.2-20, preferably 1:1-5, when the supplementary raw material is supplemented each time.
6. The method according to claim 1, characterized in that:
The dehydration treatment method is that dehydration is carried out through a dehydrating agent, preferably, the dehydrating agent is selected from anhydrous sulfate, further preferably, the dehydrating agent is selected from at least one of anhydrous copper sulfate, anhydrous ferric sulfate or anhydrous aluminum potassium sulfate; and/or the number of the groups of groups,
The temperature of the dehydration treatment is 100-250 ℃, preferably 150-200 ℃; and/or the number of the groups of groups,
The total space velocity of the material flowing through the dehydrating agent is 0.2 to 20h -1, preferably 0.5 to 5h -1.
7. The method according to claim 1, characterized in that:
the catalyst is selected from Cs-based solid base catalysts.
8. An unsaturated carboxylic acid ester prepared according to the method of any one of claims 1-7, preferably said unsaturated carboxylic acid ester is selected from at least one of methyl acrylate, methyl methacrylate or methyl 2-ethyl acrylate.
9. A reaction system for preparing unsaturated carboxylic ester by utilizing multistage condensation reaction comprises a plurality of condensation reactors, a feeding unit and an optional dehydration unit which are connected; the feed unit and optionally the dehydration unit are located between the condensation reactors;
Preferably, the reaction system is used for realizing the method for producing an unsaturated carboxylic acid ester using a multistage condensation reaction according to any one of claims 1 to 7 or for producing an unsaturated carboxylic acid ester according to claim 8.
10. The reaction system of claim 9, wherein:
the feed unit and optionally the dehydration unit are located between every two adjacent condensation reactors;
Preferably, the dehydration unit and the feed unit are both located between every two adjacent condensation reactors;
more preferably, the feed port of the dehydration unit is connected with the discharge port of the previous condensation reactor, and the discharge port of the dehydration unit is connected with the feed port of the next condensation reactor;
The discharge port of the feeding unit is communicated with the feed port of the dehydration unit or is communicated with a feed pipeline in front of the feed port of the dehydration unit.
11. The reaction system of claim 10, wherein:
when the reaction system comprises a dehydration unit, the reaction system further comprises a heat exchange unit;
Preferably, the number of the heat exchange units is more than two, and the heat exchange units are arranged between the feed inlet of the dehydration unit and the discharge outlet of the previous condensation reactor; a heat exchange unit is arranged between the discharge port of the dehydration unit and the feed port of the subsequent condensation reactor;
And a discharge port of the feeding unit is communicated with a feed port of the dehydration unit or is communicated with a feed pipeline behind the heat exchange unit in front of the feed port of the dehydration unit.
12. A Cs-based solid base catalyst, which is calculated by taking the mass of the Cs-based solid base catalyst as 100 percent,
The content of the Cs element is 0.2-60 wt%, preferably 2-20 wt%;
Preferably as a catalyst in the process of any of claims 1-7.
13. The method for preparing a Cs-based solid base catalyst according to claim 12, comprising the steps of:
the preparation method of the Cs-based solid base catalyst comprises the following steps: and loading the soluble Cs salt and the placeholder on a carrier together, and roasting to obtain the Cs-based solid base catalyst.
14. The method for preparing the Cs-based solid base catalyst according to claim 13, wherein:
The soluble Cs salt is selected from at least one of Cs 2CO3、CsNO3 and CsOH, csCl, csOAc; and/or the number of the groups of groups,
The placeholder is selected from soluble ammonium salts, preferably from at least one of (NH 4)2CO3 or NH 4 OAc), and/or,
The carrier is at least one selected from Al 2O3、SiO2 and active carbon; and/or the number of the groups of groups,
The soluble Cs salt and the placeholder forming mixture are co-supported on the support, preferably by impregnation.
15. The method for preparing the Cs-based solid base catalyst according to claim 14, wherein:
in the mixed solution, the mass concentration of the soluble Cs salt is 0.5-50%, preferably 2-20%; and/or the number of the groups of groups,
The mass concentration of the placer in the mixed solution is 0.2-30%, preferably 2-10%;
in the mixed solution, the mass ratio of the soluble Cs salt to the carrier is 1:2-200, preferably 1:5-50; and/or the number of the groups of groups,
The roasting temperature is 250-800 ℃, preferably 350-600 ℃; and/or the number of the groups of groups,
The roasting time is 2-10 h, preferably 3-6 h;
More preferably, the drying treatment is performed at a temperature of 60 to 200 ℃ for a time of 2 to 24 hours before the firing.
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