CN117164457A - Method for efficiently preparing methyl dichloroacetate - Google Patents
Method for efficiently preparing methyl dichloroacetate Download PDFInfo
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- CN117164457A CN117164457A CN202311142044.3A CN202311142044A CN117164457A CN 117164457 A CN117164457 A CN 117164457A CN 202311142044 A CN202311142044 A CN 202311142044A CN 117164457 A CN117164457 A CN 117164457A
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- Prior art keywords
- methyl dichloroacetate
- efficiently preparing
- methanol
- reaction
- preparing methyl
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- HKMLRUAPIDAGIE-UHFFFAOYSA-N methyl 2,2-dichloroacetate Chemical compound COC(=O)C(Cl)Cl HKMLRUAPIDAGIE-UHFFFAOYSA-N 0.000 title claims abstract description 49
- 238000000034 method Methods 0.000 title claims abstract description 23
- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 claims abstract description 114
- JXTHNDFMNIQAHM-UHFFFAOYSA-N dichloroacetic acid Chemical compound OC(=O)C(Cl)Cl JXTHNDFMNIQAHM-UHFFFAOYSA-N 0.000 claims abstract description 64
- 238000006243 chemical reaction Methods 0.000 claims abstract description 60
- 229960005215 dichloroacetic acid Drugs 0.000 claims abstract description 32
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 25
- 239000003054 catalyst Substances 0.000 claims abstract description 13
- 239000000203 mixture Substances 0.000 claims abstract description 12
- 239000011973 solid acid Substances 0.000 claims abstract description 10
- 238000005406 washing Methods 0.000 claims abstract description 5
- 238000010438 heat treatment Methods 0.000 claims abstract description 4
- 238000003756 stirring Methods 0.000 claims description 31
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical group O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 12
- 238000004821 distillation Methods 0.000 claims description 11
- 239000012074 organic phase Substances 0.000 claims description 11
- CSNNHWWHGAXBCP-UHFFFAOYSA-L Magnesium sulfate Chemical compound [Mg+2].[O-][S+2]([O-])([O-])[O-] CSNNHWWHGAXBCP-UHFFFAOYSA-L 0.000 claims description 9
- 239000012065 filter cake Substances 0.000 claims description 9
- 239000000706 filtrate Substances 0.000 claims description 9
- 239000000047 product Substances 0.000 claims description 5
- 238000001035 drying Methods 0.000 claims description 3
- 238000001914 filtration Methods 0.000 claims description 3
- 238000002386 leaching Methods 0.000 claims description 3
- 239000012153 distilled water Substances 0.000 claims description 2
- 238000004519 manufacturing process Methods 0.000 abstract description 8
- 230000035484 reaction time Effects 0.000 abstract description 7
- 238000009776 industrial production Methods 0.000 abstract description 5
- 239000000463 material Substances 0.000 description 15
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 6
- 230000032798 delamination Effects 0.000 description 6
- 239000012071 phase Substances 0.000 description 6
- 230000000694 effects Effects 0.000 description 5
- 238000005886 esterification reaction Methods 0.000 description 5
- 238000007789 sealing Methods 0.000 description 5
- AYIRNRDRBQJXIF-NXEZZACHSA-N (-)-Florfenicol Chemical compound CS(=O)(=O)C1=CC=C([C@@H](O)[C@@H](CF)NC(=O)C(Cl)Cl)C=C1 AYIRNRDRBQJXIF-NXEZZACHSA-N 0.000 description 4
- 230000005540 biological transmission Effects 0.000 description 4
- 230000015572 biosynthetic process Effects 0.000 description 4
- 230000000052 comparative effect Effects 0.000 description 4
- 238000005192 partition Methods 0.000 description 4
- 238000003786 synthesis reaction Methods 0.000 description 4
- 229960003053 thiamphenicol Drugs 0.000 description 4
- OTVAEFIXJLOWRX-NXEZZACHSA-N thiamphenicol Chemical compound CS(=O)(=O)C1=CC=C([C@@H](O)[C@@H](CO)NC(=O)C(Cl)Cl)C=C1 OTVAEFIXJLOWRX-NXEZZACHSA-N 0.000 description 4
- 241000894006 Bacteria Species 0.000 description 3
- 230000000844 anti-bacterial effect Effects 0.000 description 3
- 229960003760 florfenicol Drugs 0.000 description 3
- 229910052742 iron Inorganic materials 0.000 description 3
- 238000002156 mixing Methods 0.000 description 3
- 238000002360 preparation method Methods 0.000 description 3
- DLFVBJFMPXGRIB-UHFFFAOYSA-N Acetamide Chemical compound CC(N)=O DLFVBJFMPXGRIB-UHFFFAOYSA-N 0.000 description 2
- STZZWJCGRKXEFF-UHFFFAOYSA-N Dichloroacetonitrile Chemical compound ClC(Cl)C#N STZZWJCGRKXEFF-UHFFFAOYSA-N 0.000 description 2
- 230000009471 action Effects 0.000 description 2
- 230000001580 bacterial effect Effects 0.000 description 2
- 229960005091 chloramphenicol Drugs 0.000 description 2
- WIIZWVCIJKGZOK-RKDXNWHRSA-N chloramphenicol Chemical compound ClC(Cl)C(=O)N[C@H](CO)[C@H](O)C1=CC=C([N+]([O-])=O)C=C1 WIIZWVCIJKGZOK-RKDXNWHRSA-N 0.000 description 2
- 108090000765 processed proteins & peptides Proteins 0.000 description 2
- 230000002194 synthesizing effect Effects 0.000 description 2
- 108010077805 Bacterial Proteins Proteins 0.000 description 1
- 241000283690 Bos taurus Species 0.000 description 1
- AEMOLEFTQBMNLQ-AQKNRBDQSA-N D-glucopyranuronic acid Chemical compound OC1O[C@H](C(O)=O)[C@@H](O)[C@H](O)[C@H]1O AEMOLEFTQBMNLQ-AQKNRBDQSA-N 0.000 description 1
- 241000192125 Firmicutes Species 0.000 description 1
- IAJILQKETJEXLJ-UHFFFAOYSA-N Galacturonsaeure Natural products O=CC(O)C(O)C(O)C(O)C(O)=O IAJILQKETJEXLJ-UHFFFAOYSA-N 0.000 description 1
- 241000287828 Gallus gallus Species 0.000 description 1
- 206010034133 Pathogen resistance Diseases 0.000 description 1
- 108090000279 Peptidyltransferases Proteins 0.000 description 1
- 241000606701 Rickettsia Species 0.000 description 1
- 241000282887 Suidae Species 0.000 description 1
- 238000010533 azeotropic distillation Methods 0.000 description 1
- 239000000022 bacteriostatic agent Substances 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000003197 catalytic effect Effects 0.000 description 1
- 235000013330 chicken meat Nutrition 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- FBCCMZVIWNDFMO-UHFFFAOYSA-N dichloroacetyl chloride Chemical compound ClC(Cl)C(Cl)=O FBCCMZVIWNDFMO-UHFFFAOYSA-N 0.000 description 1
- 238000009826 distribution Methods 0.000 description 1
- 229940079593 drug Drugs 0.000 description 1
- 239000003814 drug Substances 0.000 description 1
- 230000032050 esterification Effects 0.000 description 1
- 125000001495 ethyl group Chemical group [H]C([H])([H])C([H])([H])* 0.000 description 1
- 229940097043 glucuronic acid Drugs 0.000 description 1
- 230000036541 health Effects 0.000 description 1
- 238000001727 in vivo Methods 0.000 description 1
- 208000015181 infectious disease Diseases 0.000 description 1
- 230000002401 inhibitory effect Effects 0.000 description 1
- 230000005764 inhibitory process Effects 0.000 description 1
- 238000009434 installation Methods 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 210000004185 liver Anatomy 0.000 description 1
- 230000005389 magnetism Effects 0.000 description 1
- 125000004170 methylsulfonyl group Chemical group [H]C([H])([H])S(*)(=O)=O 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 229940060568 nuflor Drugs 0.000 description 1
- 125000001997 phenyl group Chemical group [H]C1=C([H])C([H])=C(*)C([H])=C1[H] 0.000 description 1
- 230000001737 promoting effect Effects 0.000 description 1
- 108090000623 proteins and genes Proteins 0.000 description 1
- 102000004169 proteins and genes Human genes 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 238000011084 recovery Methods 0.000 description 1
- 238000004064 recycling Methods 0.000 description 1
- 208000023504 respiratory system disease Diseases 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C67/00—Preparation of carboxylic acid esters
- C07C67/08—Preparation of carboxylic acid esters by reacting carboxylic acids or symmetrical anhydrides with the hydroxy or O-metal group of organic compounds
-
- 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
- B01J27/02—Sulfur, selenium or tellurium; Compounds thereof
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P20/00—Technologies relating to chemical industry
- Y02P20/10—Process efficiency
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P20/00—Technologies relating to chemical industry
- Y02P20/50—Improvements relating to the production of bulk chemicals
- Y02P20/584—Recycling of catalysts
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
Abstract
The invention discloses a method for efficiently preparing methyl dichloroacetate, which comprises the steps of adding dichloroacetic acid and a solid acid catalyst into a reaction kettle, heating to a required temperature, then dropwise adding methanol, simultaneously azeotropically distilling out a mixture of methyl dichloroacetate and water, layering, washing with water, and distilling to obtain a high-purity methyl dichloroacetate product. The method is simple and convenient, is easy to operate, can effectively reduce the using amount of methanol, shortens the reaction time, improves the product yield, thereby improving the production efficiency and reducing the production cost, and is environment-friendly and more suitable for industrial production.
Description
Technical Field
The invention relates to the technical field of methyl dichloroacetate, in particular to a method for efficiently preparing methyl dichloroacetate.
Background
Florfenicol (1), chemical name 2, 2-dichloro-N- [ (1 s,2 r) -1-fluoromethyl-2-hydroxy-2- [4- (methylsulfonyl) phenyl ] ethyl ] acetamide, is a veterinary antibacterial developed by Schering-PloughAnimal Health, usa, first marketed in japan in 1990 under the trade name Nuflor. The florfenicol can be tightly combined with 50S subunits of a 70S ribosome of bacteria, interferes with the synthesis of bacterial proteins, has broad-spectrum antibacterial activity, has strong inhibition effect on drug-resistant bacteria of chloramphenicol (chlormphenicol) and thiamphenicol (thiamphenicol), can be used for treating infections of gram-positive bacteria, negative bacteria, rickettsia and the like, and has remarkable curative effect on bacterial respiratory diseases of cattle, pigs and chickens.
Thiamycin belongs to a bacteriostatic agent, and is reversibly combined with 50S subunit of bacterial ribosome, so that the growth of peptide chain is blocked (possibly because of the action of inhibiting transpeptidase), and therefore, the formation of peptide chain is printed, thereby preventing the synthesis of protein and presenting complete cross-resistance with chloramphenicol. Thiamphenicol has high in vivo antibacterial activity because it does not bind to glucuronic acid in the liver.
Dichloroacetonitrile is an important intermediate for synthesizing florfenicol and thiamphenicol, and can also be used for organic synthesis, and methyl dichloroacetate is a key intermediate for synthesizing dichloroacetonitrile. The well-known preparation method of the methyl dichloroacetate takes the dichloroacetyl chloride as a raw material for synthesis, but the preparation method has serious pollution, is extremely not friendly to the environment and has higher production cost. The methyl dichloroacetate can also be synthesized by an industrial production method of direct methanol esterification of dichloroacetic acid, but the method has the advantages of slow esterification reaction rate, long reaction time and low yield, seriously influences the efficiency of industrial production and increases the production cost.
Disclosure of Invention
The invention aims to overcome the defects of the prior art, and provides a method for efficiently preparing methyl dichloroacetate, which is simple and convenient, is easy to operate, can effectively reduce the use amount of methanol, shortens the reaction time, and improves the product yield, thereby improving the production efficiency and reducing the production cost, and is environment-friendly and more suitable for industrial production.
In order to achieve the above purpose, the present invention adopts the following technical scheme:
a process for preparing methyl dichloroacetate with high efficiency includes such steps as adding dichloroacetic acid and solid acid catalyst to reactor, heating to required temp, dropping methanol, azeotropic distillation to obtain mixture of methyl dichloroacetate and water, layering, washing with water, and distillation.
The solid acid catalyst is sulfonated silica gel (SSA).
The usage amount of the solid acid is 0.1-10% of the mass of the dichloroacetic acid.
The usage amount of the solid acid is 2-3.5% of the mass of the dichloroacetic acid.
The molar ratio of the methanol to the dichloroacetic acid is 1-10:1.
The molar ratio of the methanol to the dichloroacetic acid is 1.3-1.73:1.
The reaction temperature is 110-140 ℃.
The reaction temperature is 122-132 ℃.
The reaction temperature is 125-130 ℃.
The specific steps of layering, washing and distilling are as follows: adding water to the distilled water and methyl dichloroacetate mixture, uniformly stirring, and standing for layering; the organic phase is separated, anhydrous magnesium sulfate is added into the organic phase for drying, filtration is carried out, a filter cake is leached by methanol, the filtrate and the leaching solution are combined, and the dichloroacetic acid methyl ester is obtained after distillation.
The beneficial effects of the invention are as follows: the loss of the solid acid catalyst is almost zero during the preparation, 100% recovery and repeated recycling can be realized, and the catalytic effect is not influenced; compared with the existing industrial production process, the method is simple and convenient, is easy to operate, effectively reduces the use amount of methanol, shortens the reaction time, improves the product yield and the production efficiency, does not generate other wastes, and has good environment.
Drawings
FIG. 1 is a liquid chromatogram of the methyl dichloroacetate product of example 1 of the present invention;
FIG. 2 is a block diagram of an improved reaction vessel of the present invention;
FIG. 3 is an enlarged view of FIG. 2 at A;
FIG. 4 is an enlarged view at B in FIG. 2;
fig. 5 is an enlarged view at C in fig. 2.
In the figure: the upper kettle body 1, the partition plate 11, the upper chamber 12, the lower chamber 13, the guide rod 14, the lower kettle body 2, the guide pipe 21, the branch pipe 22, the A valve 23, the B valve 24, the stirring paddle 3, the first electromagnet 31, the motor 32, the mounting frame 4, the rotating shaft 5, the A bevel gear 51, the magnet 52, the connecting shaft 6, the B bevel gear 61, the screw rod 7, the second electromagnet 71, the gear transmission belt structure 72, the screw connector 73, the push plate 8, the iron sheet 81, the sealing ring 82, the guide pipe 9, the connecting pipe 91 and the one-way valve 92.
Detailed Description
The invention is further described with reference to the drawings and detailed description which follow:
the methyl dichloroacetate of the invention is prepared by the following method: adding dichloroacetic acid into a reaction kettle, adding sulfonated silica gel (SSA), heating to 115-130 ℃ under stirring, starting to dropwise add methanol, keeping the temperature in the reaction kettle at 110-140 ℃ for reaction, and azeotropically distilling out a mixture of water and methyl dichloroacetate while reacting. Adding water into the distillate, stirring, standing, and layering. The organic phase is taken to be added with anhydrous magnesium sulfate for drying, filtration is carried out, a filter cake is leached by methanol, filtrate and leaching solution are combined, and after distillation, the methyl dichloroacetate is obtained. In the method, the dosage of the sulfonated silica gel (SSA) is 0.1-10% of the mass of the dichloroacetic acid, preferably 2-3.5% of the mass of the dichloroacetic acid; the molar ratio of the methanol to the dichloroacetic acid is 1-10:1, preferably 1.3-1.73:1; the dosage of sulfonated silica gel (SSA), dichloroacetic acid and methanol in the esterification reaction is adjusted according to actual requirements; the reaction temperature is preferably 125-130 ℃.
Example 1
1000g of dichloroacetic acid is put into a reaction kettle, 20g of sulfonated silica gel (SSA) is put into the reaction kettle, the temperature is raised to 127 ℃ under stirring, 430g of methanol is dripped, the temperature in the reaction kettle is kept at 125-130 ℃ for reaction, the mixture of water and methyl dichloroacetate is distilled off azeotropically while the reaction is carried out, the total dripping of methanol is carried out for 5.5 hours, and after the reaction distillation is completed for 6.5 hours, almost no dichloroacetic acid remains in the bottle. 250g of water was added to the fraction and stirred for 15 minutes, followed by standing and delamination. The organic phase was taken and added with 25g of anhydrous magnesium sulfate, dried for 4 hours, filtered, the filter cake was rinsed with 30mL of methanol, the filtrate and the rinse were combined, and 1047.7g of methyl dichloroacetate was obtained after distillation, the yield was 94.5%, and the gas phase purity was 99%.
Example 2
1000g of dichloroacetic acid is put into a reaction kettle, 25g of sulfonated silica gel (SSA) is put into the reaction kettle, the temperature is raised to 127 ℃ under stirring, 430g of methanol is dripped into the reaction kettle, the reaction is carried out at the temperature of 125-130 ℃, the mixture of water and methyl dichloroacetate is distilled out while the reaction is carried out, the total dripping of methanol is carried out for 5 hours, and after the reaction distillation for 6 hours is finished, almost no dichloroacetic acid remains in a bottle. 250g of water was added to the fraction and stirred for 15 minutes, followed by standing and delamination. The organic phase was added with 25g of anhydrous magnesium sulfate, dried for 4 hours, filtered, and the filter cake was rinsed with 30mL of methanol, and the filtrate and the rinse were combined and distilled to obtain 1053.3g of methyl dichloroacetate, with a yield of 95% and a gas phase purity of 99%.
Example 3
1000g of dichloroacetic acid is put into a reaction kettle, 30g of sulfonated silica gel (SSA) is put into the reaction kettle, the temperature is raised to 127 ℃ under stirring, 430g of methanol is dripped, the reaction is carried out at the temperature of 125-130 ℃ in the reaction kettle, the mixture of water and methyl dichloroacetate is distilled out while the reaction is carried out, the total dripping of methanol is carried out for 4.5 hours, and after the reaction distillation for 5.5 hours, almost no dichloroacetic acid is remained in the bottle. 250g of water was added to the fraction and stirred for 15 minutes, followed by standing and delamination. The organic phase was added with 25g of anhydrous magnesium sulfate, dried for 4 hours, filtered, and the filter cake was rinsed with 30mL of methanol, and the filtrate and the rinse were combined and distilled to obtain 1055.5g of methyl dichloroacetate, yield 95.2%, and gas phase purity 99%.
Example 4
1000g of dichloroacetic acid and 35g of sulfonated silica gel (SSA) are added into a reaction kettle, the temperature is raised to 127 ℃ under stirring, 430g of methanol is dripped, the temperature in the reaction kettle is kept at 125-130 ℃ for reaction, the mixture of water and methyl dichloroacetate is distilled out while the reaction is carried out, the total dripping of methanol is carried out for 4.5 hours, and after the reaction distillation for 5.5 hours, almost no dichloroacetic acid is remained in a bottle. 250g of water was added to the fraction and stirred for 15 minutes, followed by standing and delamination. The organic phase was added with 25g of anhydrous magnesium sulfate, dried for 4 hours, filtered, and the filter cake was rinsed with 30mL of methanol, and the filtrate and the rinse were combined and distilled to obtain 1056.6g of methyl dichloroacetate, yield 95.3%, and gas phase purity 99%.
Comparative example 1
1000g of dichloroacetic acid is put into a reaction kettle, the temperature is raised to 127 ℃ under stirring, 430g of methanol is dripped, the temperature in the reaction kettle is kept at 125-130 ℃ for reaction, the mixture of water and methyl dichloroacetate is distilled out during the reaction, the total dripping of methanol is carried out for 7.5 hours, the reaction distillation is completed for 8.5 hours, and unreacted dichloroacetic acid remains in the bottle. 250g of water was added to the fraction and stirred for 15 minutes, followed by standing and delamination. The organic phase was added with 25g of anhydrous magnesium sulfate, dried for 4 hours, filtered, and the filter cake was rinsed with 30mL of methanol, and the filtrate and the rinse were combined and distilled to obtain 887g of methyl dichloroacetate, with a yield of 80% and a gas phase purity of 99%.
Comparative example 2
1000g of dichloroacetic acid is put into a reaction kettle, the temperature is raised to 127 ℃ under stirring, 575g of methyl alcohol is dripped, the temperature in the reaction kettle is kept at 125-130 ℃ for reaction, the mixture of water and methyl dichloroacetate is distilled out during the reaction, the total dripping of the methyl alcohol is carried out for 10 hours, and almost no dichloroacetic acid remains in the bottle after the reaction distillation is completed for 11 hours. 250g of water was added to the fraction and stirred for 15 minutes, followed by standing and delamination. The organic phase was added with 25g of anhydrous magnesium sulfate, dried for 4 hours, filtered, and the filter cake was rinsed with 30mL of methanol, and the filtrate and the rinse were combined and distilled to obtain 1008.9g of methyl dichloroacetate, yield 91%, and gas phase purity 99%.
Comparing comparative example 1 with examples 1-4, it is known that the reaction rate is accelerated after adding the sulfonated silica gel (SSA) catalyst under the same conditions of the same mass ratio of dichloroacetic acid to methanol and the same reaction temperature, the reaction time is reduced from 8.5 hours without adding the sulfonated silica gel (SSA) catalyst to 5.5 to 6.5 hours, and the reaction time is shorter as the adding amount of the sulfonated silica gel (SSA) catalyst increases, and the yield of methyl dichloroacetate increases after adding the catalyst and increases as the adding amount of the catalyst increases. Comparing comparative example 2 with example 1, it is found that the amount of methanol can be significantly reduced after the catalyst is added and the yield is higher than that without the catalyst, while ensuring the complete reaction of dichloroacetic acid.
The esterification reaction of the dichloroacetic acid and the methanol needs to be carried out in a stirring state, but in the prior art, a reaction kettle is usually provided with a stirring paddle with a single stirring direction, so that the problems of insufficient uniform mixing of reaction materials and poor heat and mass transfer effects in the reaction process exist, and the product yield is affected.
In order to further improve the yield of methyl dichloroacetate, the reaction kettle is improved, as shown in fig. 2-5, the reaction kettle comprises an upper kettle body 1 and a lower kettle body 2 which are connected up and down, the upper kettle body 1 is divided into an upper cavity 12 and a lower cavity 13 through a partition plate 11, a rotatable stirring paddle 3 is arranged in the upper cavity 12, the lower end of a shaft of the stirring paddle 3 stretches into the lower cavity 13, a mounting frame 4 is fixedly connected to the lower surface of the partition plate 11, a rotating shaft 5 is arranged in the mounting frame 4, the rotating shaft 5 and the shaft of the stirring paddle 3 are vertically arranged at intervals and concentrically, and the stirring paddle 3 drives the rotating shaft 5 to rotate in the same direction or in different directions through electromagnetic action.
Specifically, a first electromagnet 31 is fixedly connected to the shaft of the stirring paddle 3 extending into the lower chamber 13, an a bevel gear 51 is fixedly arranged on the rotating shaft 5, a magnet 52 is fixedly arranged on the a bevel gear 51, and the magnet 52 is located on the outer ring of the first electromagnet 31. The first electromagnet 31 and the magnet 52 are opposite to each other inside and outside, the stirring paddle 3 is driven to rotate through the motor 32, if the first electromagnet 31 and the magnet 52 are arranged in the same polarity, the driving rotating shaft 5 reversely rotates when the stirring paddle 3 rotates, if the first electromagnet 31 and the magnet 52 are arranged in different polarities, the driving rotating shaft 5 reversely rotates when the stirring paddle 3 rotates, and the stirring paddle 3 drives the rotating shaft 5 to rotate in the same direction or in different directions through changing the polarity of the first electromagnet 31.
The lower chamber 13 is internally provided with a connecting shaft 6 and a screw rod 7, the connecting shaft 6 is meshed with the A bevel gear 51 through the B bevel gear 61, and the screw rod 7 is positioned below the connecting shaft 6 and the connecting shaft 6 is in transmission connection with the screw rod 7. Specifically, the mounting frame 4 is of a U-shaped frame structure, and the upper end of the mounting frame 4 is fixedly connected with the partition plate 11. The lower end of the rotating shaft 5 is rotationally connected with the bottom of the mounting frame 4, the bevel gear 51 positioned at A is positioned in the mounting frame 4, the inner end of the connecting shaft 6 rotationally passes through one side of the mounting frame 4 and then extends into the mounting frame 4, and the outer end of the connecting shaft 6 is rotationally connected with the side wall of the upper kettle body 1; the connecting shaft 6 is in transmission connection with the screw rod 7 through a gear transmission belt structure 72. When the rotating shaft 5 is driven to rotate positively and negatively by the stirring paddle 3, the connecting shaft 6 is driven to rotate positively and negatively by the bevel gears A51 and B61, and the connecting shaft 6 drives the screw rod 7 to rotate positively and negatively.
The lower chamber 13 is internally provided with a second electromagnet 71 which is driven to move back and forth by a screw rod 7, the lower kettle body 2 is internally provided with a vertical pushing plate 8 which is in sealing fit with the inner wall of the lower kettle body 2, and the second electromagnet 71 moves back and forth to drive the pushing plate 8 to move back and forth. Specifically, the second electromagnet 71 is in threaded connection with the screw rod 7 through a threaded connection piece 73, the lower part of the second electromagnet 71 is in sliding connection with the bottom of the upper kettle body 1 or a gap of 0.2-1mm is reserved between the lower part of the second electromagnet 71 and the bottom of the upper kettle body 1; the lower chamber 13 is internally provided with a transverse guide rod 14, the guide rod 14 slides through the screw connection piece 73, and the guide rod 14 passes through a space surrounded by a gear of the gear drive belt structure 72 and the drive belt, so that the guide rod 14 does not interfere with the gear drive belt structure 72. An iron sheet 81 matched and adsorbed with the second electromagnet 71 is embedded in the upper part of the push plate 8. The inner cavity of the lower kettle body 2 is of a cuboid or transverse semi-cylindrical structure, the push plate 8 is guided, the annular edge of the push plate 8 and the inner wall of the lower kettle body 2 are sealed through two rings of sealing rings 82, and an iron sheet 81 is positioned between the two rings of sealing rings 82, so that the push plate 8 and the lower kettle body 2 are in sealing connection, and the push plate 8 can be driven to move by the second electromagnet 71.
The utility model discloses a stirring device for a water heater, including upper cavity 12, lower cavity 12, connecting pipe 91, connecting pipe 21, connecting pipe 9, connecting pipe 21 and connecting pipe 9, connecting pipe 91 is connected with circumference distribution's connecting pipe 91 on the honeycomb duct 9, connecting pipe 91 stretches into in the upper cavity 12 and for inwards and upward slope setting, the connecting pipe 91 is embedded to be equipped with the check valve 92 of export orientation stirring rake 3, lower cauldron body 2 left and right sides all is connected with honeycomb duct 9 through pipe 21, opening end installation A valve 23 on pipe 21, pipe 21 passes through branch pipe 22 and is connected with upper cavity 12 bottom, installs B valve 24 on the branch pipe 22, and branch pipe 22 is located the below of A valve 23.
As shown in fig. 2, the push plate 8 is initially positioned on the right side of the inner cavity of the lower kettle body 2, and both the valve A23 and the valve B24 are closed, so that the inner cavity of the lower kettle body 2 is empty. When the esterification reaction is carried out by the improved reaction kettle, the stirring paddle 3 rotates to stir the materials in the upper chamber 12, the valve B24 on the left side is opened, and part of the materials flow into the lower chamber 13 on the left side of the push plate 8 through the branch pipe 22 and the guide pipe 21 on the left side; after the lower chamber 13 is full of the materials, the first electromagnet 31 and the second electromagnet 71 are electrified, the left side B valve 24 is closed, the left side A valve 23 is opened, the right side B valve 24 is opened, the A bevel gear 51 drives the B bevel gear 61 to rotate along with the rotation of the stirring paddle 3 through the first electromagnet 31, and then the screw rod 7 rotates, so that the push plate 8 is driven to move leftwards through the second electromagnet 71, the materials in the lower chamber 13 are pushed into the left side guide pipe 21 and then enter the guide pipe 9, and are sprayed out through the connecting pipe 91, and meanwhile, part of the materials in the upper chamber 12 flow into the lower chamber 13 on the right side of the push plate 8 through the right side guide pipe 9; when the push plate 8 moves leftwards to be abutted against the left inner wall of the lower kettle body 2, the inner cavity of the lower kettle body 2 on the right side of the push plate 8 is filled with materials, the magnetism of the first electromagnet 31 is changed, the left side valve B24 is opened, the left side valve A23 is closed, the right side valve B24 is closed, the right side valve A23 is opened, the push plate 8 moves rightwards to push the materials in the lower kettle body 2 to enter the guide pipe 9 after passing through the right side guide pipe 21, and then the materials are sprayed out through the connecting pipe 91. Through the repeated operation of the method, the materials in the upper chamber 12 flow into the lower kettle body 2 and flow back to the upper chamber 12, so that the circulating flow of the reaction materials is realized, the situation that the materials at the bottom of the upper chamber 12 cannot be fully stirred and cannot fully participate in the reaction can be effectively avoided, the reaction materials are sprayed back into the upper chamber 12 through the connecting pipes 91 distributed circumferentially, the effect of promoting the mixing of the materials in the upper chamber 12 is achieved, the mixing uniformity of the materials is further promoted, and the effective proceeding of the reaction is promoted by combining the stirring effect of the stirring paddles 3.
The improved reaction kettle is adopted to prepare the methyl dichloroacetate according to the method of examples 1-4, and the average yield of the methyl dichloroacetate is improved by 1.81 percent, and the average reaction time is shortened by 35 minutes.
The foregoing description of the preferred embodiments of the invention is not intended to limit the invention to the precise form disclosed, and any such modifications, equivalents, and alternatives falling within the spirit and scope of the invention are intended to be included within the scope of the invention.
Claims (10)
1. A method for efficiently preparing methyl dichloroacetate is characterized by comprising the following steps: adding dichloroacetic acid and a solid acid catalyst into a reaction kettle, heating to a required temperature, then dropwise adding methanol, simultaneously azeotropically distilling out a mixture of methyl dichloroacetate and water, and layering, washing with water and distilling to obtain a high-purity methyl dichloroacetate product.
2. A method for efficiently preparing methyl dichloroacetate according to claim 1, wherein: the solid acid catalyst is sulfonated silica gel.
3. A method for efficiently preparing methyl dichloroacetate according to claim 1, wherein: the usage amount of the solid acid is 0.1-10% of the mass of the dichloroacetic acid.
4. A method for efficiently preparing methyl dichloroacetate according to claim 1, wherein: the usage amount of the solid acid is 2-3.5% of the mass of the dichloroacetic acid.
5. A method for efficiently preparing methyl dichloroacetate according to claim 1, wherein: the molar ratio of the methanol to the dichloroacetic acid is 1-10:1.
6. A method for efficiently preparing methyl dichloroacetate according to claim 1, wherein: the molar ratio of the methanol to the dichloroacetic acid is 1.3-1.73:1.
7. A method for efficiently preparing methyl dichloroacetate according to claim 1, wherein: the reaction temperature is 110-140 ℃.
8. A method for efficiently preparing methyl dichloroacetate according to claim 1, wherein: the reaction temperature is 122-132 ℃.
9. A method for efficiently preparing methyl dichloroacetate according to claim 1, wherein: the reaction temperature is 125-130 ℃.
10. A method for efficiently preparing methyl dichloroacetate according to claim 1, wherein: the specific steps of layering, washing and distilling are as follows: adding water to the distilled water and methyl dichloroacetate mixture, uniformly stirring, and standing for layering; the organic phase is separated, anhydrous magnesium sulfate is added into the organic phase for drying, filtration is carried out, a filter cake is leached by methanol, the filtrate and the leaching solution are combined, and the dichloroacetic acid methyl ester is obtained after distillation.
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| CN110668963A (en) * | 2019-09-05 | 2020-01-10 | 湖南恒泰生物医药有限公司 | Method for synthesizing dichloroacetamide |
| CN111747849A (en) * | 2020-07-02 | 2020-10-09 | 浙江建业化工股份有限公司 | Method for synthesizing n-propyl acetate by continuous catalytic esterification of benzenesulfonic acid and derivatives thereof |
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| CN205152122U (en) * | 2015-11-05 | 2016-04-13 | 山东省化工研究院 | Methyl chloroacetate preparation facilities |
| CN108947835A (en) * | 2018-03-19 | 2018-12-07 | 山东润博生物科技有限公司 | A kind of preparation method of phenoxy acetic acid ester |
| CN113501838A (en) * | 2021-07-09 | 2021-10-15 | 大连海关技术中心 | Preparation method of organic silicon sulfonic acid and salts thereof |
| CN115805083A (en) * | 2021-09-13 | 2023-03-17 | 马国飞 | Use of inorganic solid silicon-based sulfonic acid as catalyst |
| CN115558476B (en) * | 2022-12-06 | 2023-02-03 | 中国石油大学(华东) | Drilling fluid resistant to-55 ℃ for Antarctic and preparation method and application thereof |
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| CN101328149A (en) * | 2008-07-29 | 2008-12-24 | 青州艾利通化工科技有限公司 | Novel allantoin synthesis process |
| CN102115431A (en) * | 2010-12-30 | 2011-07-06 | 台州学院 | Synthesis method of 2, 2-ethoxyethanol |
| CN105251538A (en) * | 2015-10-28 | 2016-01-20 | 湖北师范学院 | Preparation method of catalyst H6P2W15Mo3O62/TiO2 and n-pentyl acetate |
| CN110668963A (en) * | 2019-09-05 | 2020-01-10 | 湖南恒泰生物医药有限公司 | Method for synthesizing dichloroacetamide |
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| CN116478038A (en) | 2023-07-25 |
| CN117164457B (en) | 2024-04-16 |
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Denomination of invention: An efficient method for preparing methyl dichloroacetate Granted publication date: 20240416 Pledgee: Zhejiang Shaoxing Hengxin Rural Commercial Bank Co.,Ltd. Mashan sub branch Pledgor: Zhejiang Zhixing Pharmaceutical Co.,Ltd. Registration number: Y2024980018223 |