Method for producing chloroacetic acid mixed acid and trichloroacetyl chloride by utilizing residues in chloroacetyl chloride production process

Abstract

The invention discloses a method for producing chloroacetic acid mixed acid and trichloroacetyl chloride by using residues in the production process of chloroacetyl chloride, and belongs to the field of chemical technology. In the method, the production process of chloroacetyl chloride is to pass chlorine gas into chloroacetic acid under sulfur as a catalyst, and the residue is a black tar-like solid at room temperature, has fluidity above 80°C, and has a pungent sour smell and the smell of rotten apples. The invention analyzes and determines the material components and contents in the residues in the production process of chloroacetyl chloride, and obtains a chloroacetic acid mixed acid with low moisture content and can be directly used by quantitative hydrolysis. The invention uses the residues in the production process of chloroacetyl chloride as raw materials to produce chloroacetic acid mixed acid and trichloroacetyl chloride, which not only solves the problem of waste polluting the environment, but also utilizes it and reduces the cost of manufacturing products.

Description

Technical Field

[0001] The invention belongs to the field of chemical industry, and particularly relates to a method for producing chloroacetic acid mixed acid and trichloroacetyl chloride by utilizing residues in the production process of chloroacetyl chloride. Background Art

[0002] Chloroacetyl chloride is an important organic intermediate. Due to its high reactivity, it has greater advantages as an acylating agent in terms of the yield and quality of synthetic products than other acylation methods. Therefore, it is widely used in the synthesis of pesticides, medicines, dyes, additives, extraction solvents, refrigerants, fire extinguishing agents, lubricant additives, and military poison gas.

[0003] In the pesticide field, chloroacetyl chloride is mainly used to synthesize dithiophosphate and monothiophosphate insecticides, acaricides, and chloroacetamide herbicides. In medicine, chloroacetyl chloride can be used to synthesize drugs for treating gastric ulcers, cardiovascular diseases, anticancer drugs, drugs for treating central nervous system diseases, and synthetic antibiotics. In addition, chloroacetyl chloride is also used to prepare praziquantel drugs for killing schistosomiasis, tetrahydrofuran drugs for preparing platelet activity inhibitors, and other drugs and pharmaceutical intermediates.

[0004] In terms of dyes, it can be used to synthesize N-chloroacetylamine intermediates and synthesize neutral brilliant blue GL dyes, polyester fiber special dyes and azo disperse red, etc.

[0005] In terms of food and feed additives, chloroacetyl chloride is mainly used to synthesize various amino acids, and can also be used to produce quinolone, a growth promoter for livestock and poultry.

[0006] In other aspects, chloroacetyl chloride can be used as a polymerization catalyst, a polymer stabilizer and modifier, a surface treatment agent, a surface coating to prevent splashing during metal welding, a lubricant additive, a bleaching agent, a metal chelating agent, and a surfactant.

[0007] The industrial production of chloroacetyl chloride generally uses chloroacetic acid with sulfur as a catalyst and chlorine gas. The advantages of this method are high product purity, low investment, simple operation, and easy to master, so this process is now widely used. The disadvantage is that the residual hazardous waste is about 5% of the output, which has not been studied and solved so far. The fundamental reason is that it is not known whether there are usable substances in the residue. Chloroacetyl chloride produces kettle residues in the production process. It is a black tar-like solid at room temperature and has fluidity above 80°C. It has a pungent sour smell and the smell of rotten apples. It is generally difficult to handle. It can only be treated by neutralization with a strong alkali and then combustion, and the treatment cost is relatively high. Chloroacetyl chloride has a large market demand and a large output. The annual output of chloroacetyl chloride in China is about 100,000 tons, and the residue in the production process is about 5%, which is about 5,000 tons per year. The residues were previously treated as hazardous waste, and the treatment cost was too high. Summary of the invention

[0008] In order to solve the above problems, after analysis and research, it was determined that the main component of the residue was mixed anhydride, accounting for about 90% of the total residue. The distribution of various chloroacetic acids was analyzed to be 94% of monochloroacetic acid, about 5% of dichloroacetic acid, and about 0.5% of trichloroacetic acid. In addition to the mixed anhydride accounting for about 90% of the total, there are about 5% of carbonized substances and about 5% of chloroacetyl chloride.

[0009] According to the analysis, the composition is a mixed acid. We speculate that the mixed anhydrides in the residue include: monochloroacetic anhydride, dichloroacetic anhydride, a mixed anhydride of monochloroacetic acid and dichloroacetic acid, a mixed anhydride of monochloroacetic acid and trichloroacetic acid, and other low-content mixed anhydrides. Because mixed anhydrides are not pure substances, there is no direct use for the mixed anhydrides after extraction. The only way is to decompose the mixed anhydrides into various chloroacetic acid mixtures, and this chloroacetic acid mixture can only be used as a raw material for the production of trichloroacetyl chloride or trichloroacetic acid.

[0010] The extraction of mixed anhydrides adopts organic solvent extraction. In principle, any solvent that can dissolve mixed anhydrides can be used as the extraction solvent, but solvents that react with anhydrides cannot be used, such as methanol, ethanol and other alcohol solvents. Therefore, the common solvents that can be selected are ethyl acetate, benzene, toluene, xylene, chloroform, dichloroethane, etc. It is recommended not to use highly toxic aromatic solvents.

[0011] After the mixed anhydride is extracted, water is added for hydrolysis to convert the mixed anhydride into a mixed acid. In principle, the greater the amount of water, the more thorough the hydrolysis. However, in practice, a mixed acid with a large water content is not conducive to production and use. Due to excessive water content, it cannot be directly used as a raw material for the production of trichloroacetic acid and trichloroacetyl chloride. It needs to be dehydrated to a water content of less than 0.5% to meet the requirements for the use of raw materials for the production of trichloroacetic acid and trichloroacetyl chloride.

[0012] This patent describes the quantitative hydrolysis of mixed anhydrides, the water content of the obtained mixed acid is less than 0.5%. At the same time, during the hydrolysis process, the hydrolysis temperature is controlled to be no less than 60°C to prevent the hydrolysis reaction from not being completely initiated at low temperatures, which may cause an instantaneous explosive reaction and create a safety hazard.

[0013] In the process of treating the reaction residue, about 5% of chloroacetyl chloride is hydrolyzed at the same time, which is more advantageous in terms of treatment cost.

[0014] The first aspect of the present invention is to disclose a method for producing chloroacetic acid mixed acid using residues in the production process of chloroacetyl chloride, characterized in that the chloroacetyl chloride production process is to introduce chlorine gas into chloroacetic acid under the condition of sulfur as a catalyst, and the residue is a black tar-like solid at room temperature, has fluidity above 80°C, and has a pungent sour smell and the smell of rotten apples.

[0015] In some preferred embodiments of the present invention, the following steps are included:

[0016] S01, taking the residue, dissolving it with a solvent, filtering it, and obtaining a filtrate;

[0017] S02, adding water to the filtrate to carry out a hydrolysis reaction;

[0018] S03, distilling off the solvent.

[0019] In some preferred embodiments of the present invention, in S01, the solvent is one or more of ethyl acetate, toluene or chloroform.

[0020] In some preferred embodiments of the present invention, in S01, the dissolution step is carried out in a flask, and the ratio of the residue to the solvent is 300 g:700-800 g.

[0021] In some preferred embodiments of the present invention, in S01, a dissolution step is performed in a reactor, and the ratio of the residue to the solvent is 1800 kg: 4000-5000 kg.

[0022] In some preferred embodiments of the present invention, in S01, the dissolving is carried out by heating to 50-80°C.

[0023] In some preferred embodiments of the present invention, in S02, the filtrate is heated to not less than 60° C. and then water is added to carry out a hydrolysis reaction.

[0024] The second aspect of the present invention is to disclose a method for preparing trichloroacetyl chloride using a chloroacetic acid mixed acid produced by the method described in the first aspect, comprising the following steps:

[0025] S11, putting the mixed chloroacetic acid and sulfur into a reaction kettle, raising the temperature, and passing chlorine gas until all of them are dissolved;

[0026] S12, raising the temperature and passing chlorine until the reflux liquid turns yellow, then stop passing chlorine;

[0027] S13, cooling, adding pyridine, heating, and passing chlorine again until the chlorination reaction liquid no longer absorbs chlorine, and then stopping passing chlorine;

[0028] S14, continue heating to drive out free chlorine in the reaction solution, then cool down, and then transfer the chlorinated liquid to a distillation system for distillation to obtain the trichloroacetyl chloride.

[0029] In some preferred embodiments of the present invention, the weight ratio of the mixed chloroacetic acid, sulfur and pyridine is 2000:(350-370):(6-8).

[0030] In some preferred embodiments of the present invention, in S11, the temperature is raised to 48-55°C,

[0031] In some preferred embodiments of the present invention, in S12, the temperature is raised to 65-75°C.

[0032] In some preferred embodiments of the present invention, in S13, the temperature is lowered to 38-45°C.

[0033] In some preferred embodiments of the present invention, in S13, the temperature is raised to 60°C-65°C.

[0034] In some preferred embodiments of the present invention, in S14, the temperature is lowered to 35°C-40°C.

[0035] In some preferred embodiments of the present invention, the temperature control of heating up and cooling down is performed by switching on and off condenser cooling water, switching on and off jacket steam, or generating heat through reaction.

[0036] The beneficial technical effects of the present invention are:

[0037] (1) The present invention analyzes and determines the material composition and content of the residue in the production process of chloroacetyl chloride, and obtains a chloroacetic acid mixed acid with low water content and directly usable through quantitative hydrolysis.

[0038] (2) The present invention uses the residues in the production process of chloroacetyl chloride as raw materials to produce chloroacetic acid mixed acid and trichloroacetyl chloride, which not only solves the problem of waste polluting the environment, but also utilizes it and reduces the cost of manufacturing products.

[0039] (3) The present invention found that the hydrolysis temperature of the residue in the solvent is not less than 60°C. When the hydrolysis temperature is lower than 60°C, the reaction speed is slow, and it is easy to add too much material dropwise, resulting in a large amount of unreacted material accumulating in the reactor. Once the temperature in the reactor exceeds 60°C, the reaction will occur instantly, and the reaction heat cannot be transferred instantly, causing an explosion. DETAILED DESCRIPTION

[0040] The following describes the embodiments of the present invention through specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention.

[0041] The slow heating means that the heating rate is lower than 5°C / min.

[0042] Unless otherwise specified, the examples and comparative examples are parallel tests with the same components, component contents, preparation steps and preparation parameters.

[0043] Example 1

[0044] A 2000ml four-necked flask is equipped with an electric stirrer, a thermometer, and a reflux condenser. Weigh 300 grams of the chloroacetyl chloride residue produced and put it into the four-necked flask, and add 750 grams of ethyl acetate solvent. Stir continuously and heat with an electric heating jacket, slowly raise the temperature to 50°C, filter while hot to remove insoluble impurities, and collect the filtrate for later use.

[0045] The filtrate was put back into a 2000 ml four-necked reaction bottle, equipped with an electric stirrer, a thermometer, a reflux condenser and a constant pressure dropping funnel, and 28.5 g of water was weighed into the constant pressure dropping funnel. Under constant stirring, the mixture was heated with an electric heating jacket, and the temperature was slowly raised to 60°C. The water in the constant pressure dropping funnel was slowly added dropwise into the reaction bottle for hydrolysis reaction. The reaction was completed in about 1 hour.

[0046] The above reaction device was changed into a distillation device. Under constant stirring, the temperature was slowly raised to evaporate the solvent ethyl acetate. When the solvent was basically no longer discharged at 100°C, it was changed into reduced pressure distillation. The vacuum degree was gradually increased according to the amount of discharge, until the vacuum degree reached -0.095MPa and the temperature was 100°C and no more discharge was observed. 313 g of mixed chloroacetic acid was recovered from the bottom of the kettle.

[0047] Example 2

[0048] A 2000ml four-necked flask is equipped with an electric stirrer, a thermometer, and a reflux condenser. 300g of the chloroacetyl chloride residue produced is weighed and put into the flask, and 750g of toluene solvent is added. While stirring continuously, heat with an electric heating jacket and slowly raise the temperature to 80°C. Filter while hot to remove insoluble impurities, and collect the filtrate for later use.

[0049] The filtrate was put back into a 2000 ml four-necked reaction bottle, equipped with an electric stirrer, a thermometer, a reflux condenser and a constant pressure dropping funnel, and 28.5 g of water was weighed into the constant pressure dropping funnel. Under constant stirring, the mixture was heated with an electric heating jacket, and the temperature was slowly raised to 60°C. The water in the constant pressure dropping funnel was slowly dripped into the reaction bottle for hydrolysis reaction. The reaction was completed in about 1 hour.

[0050] The above reaction device was changed into a distillation device. Under constant stirring, the temperature was slowly raised to evaporate the solvent toluene. When the solvent was basically no longer discharged at 120°C, it was changed into reduced pressure distillation. The vacuum degree was gradually increased according to the amount of discharge, until the vacuum degree reached -0.095MPa and the temperature was 120°C until no more discharge was observed. 314 g of mixed chloroacetic acid was recovered from the bottom of the kettle.

[0051] Example 3

[0052] A 2000ml four-necked flask is equipped with an electric stirrer, a thermometer, and a reflux condenser. 400g of the chloroacetyl chloride residue produced is weighed and put into the flask, and 1000g of chloroform solvent is added. While stirring continuously, heat with an electric heating jacket and slowly raise the temperature to 50°C. Filter while hot to remove insoluble impurities, and collect the filtrate for later use.

[0053] The filtrate was put back into a 2000 ml four-necked reaction bottle, equipped with an electric stirrer, a thermometer, a reflux condenser and a constant pressure dropping funnel, and 38.0 g of water was weighed into the constant pressure dropping funnel. Under constant stirring, the mixture was heated with an electric heating jacket, and the temperature was slowly raised to 60°C. The water in the constant pressure dropping funnel was slowly added dropwise into the reaction bottle for hydrolysis reaction. The reaction was completed in about 1 hour.

[0054] The above reaction device was changed into a distillation device. Under constant stirring, the temperature was slowly raised to evaporate the solvent chloroform. When the solvent was basically no longer discharged at 100°C, it was changed into reduced pressure distillation. The vacuum degree was gradually increased according to the amount of discharge, until the vacuum degree reached -0.095MPa and the temperature was 100°C and no more discharge was observed. 422g of mixed chloroacetic acid was recovered from the bottom of the kettle.

[0055] Example 4

[0056] 6300L enamel reactor, put into production chloroacetyl chloride residue 1800kg, put into dichloroethane solvent 4500kg. Under continuous stirring, open the jacket for steam heating, slowly raise the temperature to 50℃, press filter while hot to remove insoluble impurities, and the filtrate enters the hydrolysis kettle.

[0057] The filtrate was slowly heated to 60°C with steam under constant stirring, and 170 kg of water in the metering tank was slowly added dropwise to carry out a hydrolysis reaction. The reaction was completed in about 2 hours.

[0058] Normal pressure and reduced pressure distillation to remove solvent. The reaction liquid after hydrolysis is placed in a distillation kettle, first at normal pressure, under constant stirring, and slowly heated with steam to evaporate the solvent dichloroethane. When the solvent is basically no longer discharged at 120°C, it is changed to reduced pressure distillation, and the vacuum degree is gradually increased according to the amount of discharge, until the vacuum degree reaches -0.095MPa and the temperature is 120°C until no more discharge occurs. After the dichloroethane in the kettle is completely removed, the jacket is opened to circulate water while maintaining the vacuum state in the kettle and stirring continuously, the kettle temperature is lowered to 80°C, and then the vacuum is removed until the kettle is at normal pressure, and stirring is stopped. The drum is weighed, and 1,880 kg of the kettle bottom material mixed with chloroacetic acid is recovered.

[0059] Example 5

[0060] In a 3000L enamel chlorination reactor, 2000 kg of the mixed chloroacetic acid produced in Example 4 and 360 kg of sulfur are added. The condenser cooling water and tail gas absorption system are turned on, and the jacket steam heating is opened under continuous stirring, and the temperature is slowly raised to 50 ° C. The chlorine gas is started to flow until all are melted. The jacket heating is closed at the same time, and the chlorination reaction is naturally warmed to 70 ° C. When the reflux color turns yellow, the chlorine gas is stopped. The temperature is lowered to 40 ° C, 7 kg of pyridine is added, and then the temperature is raised to more than 60 ° C. The chlorine gas is passed again until the chlorination reaction liquid no longer absorbs chlorine gas, and the chlorine gas is stopped. The free chlorine in the reaction solution is driven out by heating, and then the temperature is lowered to less than 40 ° C. After that, the chlorinated liquid is transferred to the distillation system for distillation, and 105 kg of the fore-reserved portion is obtained, and the content is 93.5%, and 3662 kg of the product trichloroacetyl chloride is obtained, and the content is 99.45%, and the yield is 95%.

[0061] Among them, the gas chromatography detection conditions of trichloroacetyl chloride are:

[0062] The column temperature was maintained at 80°C for 3 minutes on a SE-30 column, then raised to 180°C at a rate of 15°C / min and maintained for 10 minutes.

[0063] The injection port was 250°C, the detector was 250°C, and the pre-column pressure was 0.06MPa.

[0064] Injection volume: 2 μL. Direct injection detection.

[0065] The preferred specific implementation modes and embodiments of the present invention are described in detail above, but the present invention is not limited to the above implementation modes and embodiments, and various changes can be made within the knowledge scope of those skilled in the art without departing from the concept of the present invention.

Claims

1. A method for producing chloroacetic acid mixed acid using residues in the production process of chloroacetyl chloride, characterized in that: The chloroacetyl chloride production process is to pass chlorine gas into chloroacetic acid under sulfur as a catalyst, and the residue is a black tar-like solid at room temperature, has fluidity above 80°C, and has a pungent sour smell and the smell of rotten apples; The following steps are involved: S01, taking the residue, dissolving it with a solvent, filtering it, and obtaining a filtrate; S02, adding water to the filtrate to carry out a hydrolysis reaction; S03, distilling out the solvent; In S01, the solvent is one or more of ethyl acetate, toluene or chloroform.

2. The method according to claim 1, characterized in that In S01, a dissolution step is performed in a flask, and the ratio of the residue to the solvent is 300 g:700-800 g; And / or, in S01, a dissolving step is performed in a reactor, and the ratio of the residue to the solvent is 1800kg:4000-5000kg.

3. The method according to claim 1 or 2, characterized in that: In S01, the dissolution is carried out by heating to 50-80°C.

4. The method according to claim 1 or 2, characterized in that: In S02, the filtrate is heated to not less than 60° C. and then water is added to carry out a hydrolysis reaction.

5. A method for preparing trichloroacetyl chloride, characterized in that: The following steps are involved: Producing chloroacetic acid mixed acid by the method according to any one of claims 1 to 4; S11, putting the mixed chloroacetic acid and sulfur into a reaction kettle, raising the temperature, and passing chlorine gas until all of them are dissolved; S12, raising the temperature and passing chlorine until the reflux liquid turns yellow, then stop passing chlorine; S13, cooling, adding pyridine, heating, and passing chlorine again until the chlorination reaction liquid no longer absorbs chlorine, and then stopping passing chlorine; S14, continue heating to drive out free chlorine in the reaction solution, then cool down, and then transfer the chlorinated liquid to a distillation system for distillation to obtain the trichloroacetyl chloride.

6. The method for preparing trichloroacetyl chloride according to claim 5, characterized in that: The weight ratio of the mixed chloroacetic acid, sulfur and pyridine is 2000: (350-370): (6-8).

7. The method for preparing trichloroacetyl chloride according to claim 5 or 6, characterized in that: In S11, the temperature is raised to 48-55°C; and / or, in S12, the temperature is raised to 65-75° C.; and / or, in S13, cooling to 38-45° C.; and / or, in S13, the temperature is raised to 60° C.-65° C.; And / or, in S14, the temperature is lowered to 35°C-40°C.

8. The method for preparing trichloroacetyl chloride according to claim 5, characterized in that: Temperature control is performed by switching on and off condenser cooling water, switching on and off jacket steam or reaction heat to increase and decrease the temperature.