CN1163264A - Process for producing p-toluenesulfonyl chloride - Google Patents
Process for producing p-toluenesulfonyl chloride Download PDFInfo
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- CN1163264A CN1163264A CN 97101400 CN97101400A CN1163264A CN 1163264 A CN1163264 A CN 1163264A CN 97101400 CN97101400 CN 97101400 CN 97101400 A CN97101400 A CN 97101400A CN 1163264 A CN1163264 A CN 1163264A
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- chlorosulfonic acid
- toluenesulfonyl chloride
- toluene
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Abstract
The present invention is a new method of producing p-toluenesulfonyl chloride with methylbenzene and chlorosulfonic acid as material and the said method is that after the reaction of methylbenzene and chlorosulfonic acid, the product produces crystal mixture at the stirring speed of 2-50 rpm in crystallizer with the crystalization temp. being minus 10 to plus 30 deg.C and crystallization time being 1-8 hr, and after direct filtration and water washing, p-toluenesulfonyl chloride is obtained. The said method has short technological period, low power consumption, high product quality and low material consumption, and the waste sulfuric acid produced in technological process has a concentration over 90% and is easy to re-use.
Description
The present invention belongs to a method for preparing organic fine chemical products of p-toluenesulfonic acid chloride.
There are several methods for producing p-toluenesulfonyl chloride, among which there are a method mainly for producing an adjacent body (o-toluenesulfonyl chloride), which produces the adjacent body (p-toluenesulfonyl chloride) as a by-product thereof, and a method mainly for producing the opposite body, which produces an adjacent isomer as a by-product thereof. There are also several different methods for the method based on the counter-body. Such as German patent Ger P1172258, Ger P1112978. In the method of JP Sho 56-46860 of U.S. Pat. No. US3.686.300, the method of genus US3.686.300 in which the yield of the target is high has been reported industrially (see Shanxi chemical industry in Liu Guo Liang, China) 1, 27, 1990). The method mainly comprises the following steps: toluene reacts with excess chlorosulfonic acid in the presence of certain salts, and the resulting mixture is slowly added dropwise to ice water, causing the excess chlorosulfonic acid to react with water to form sulfuric acid and release a large amount of heat. The p-toluenesulfonyl chloride separated in the way is still mixed with impurities such as vicinal bodies and the like, and a final product is obtained after further separation. The consumption of chlorosulfonic acid is still more, the waste sulfuric acid produced in the production is too dilute, it is not favourable for industrial utilization and treatment, and when it is hydrolyzed, it has more cold quantity and consumes large quantity of electric energy.
The invention aims to overcome the defects in the prior art and provide a method for preparing paratoluensulfonyl chloride. Firstly, the target product in the mixture after the reaction of toluene and chlorosulfonic acid is fully crystallized under a certain condition, and the crystal particles are enlarged. The para-chlorine is separated from the mixture by adopting a method of direct filtration without hydrolysis, so that most of by-products and impurities are remained in the solution as much as possible, thereby greatly improving the purity and color of the product. Simultaneously, the consumption of chlorosulfonic acid is reduced. The invention also aims to obtain a waste sulfuric acid containing a certain amount of unreacted chlorosulfonic acid, so that the chlorosulfonic acid which is inevitably and excessively existed in the reaction can be reused without being damaged. At the same time, more than 90% concentrated sulfuric acid can be obtained, which also provides convenience for the utilization and treatment of waste sulfuric acid.
The object of the invention can be achieved by the following measures: the above-mentioned industrial toluene and chlorosulfonic acid are used as raw material, and reacted in a reactor in the presence of alkali metal, alkaline earth metal or ammonium salt, and the hydrogen chloride produced by reaction can be discharged. After the reaction, a mixture is obtained, the target product is completely crystallized through a crystallization process, then the crystallization is separated by a filtration method, and then the isomer is further washed and separated to obtain the para-chlorine product with higher purity. The reaction equation can be expressed as:
The feeding sequence during the reaction is as follows: leading half of chlorosulfonic acid required by reaction into a reactor, adding a salt, controlling the reaction temperature to be 60-100 ℃, dropwise adding toluene, cooling the reaction material to 10-40 ℃, adding the other half of chlorosulfonic acid, reacting for 1-4 hours, wherein the molar ratio of the reaction material to the toluene to the chlorosulfonic acid is 1: 2-4, and the molar ratio of the salt to the toluene to the salt is 1: 0.3-0.7. After the reaction is finished, fully crystallizing the para-position body and enlarging crystal particles in a crystallizer with the stirring speed of 2-50 r/min at the crystallization temperature of-10-30 ℃ for 1-8 hours; after full crystallization, the mixture is directly filtered, and the filter cake is washed by water to separate out isomers, thus obtaining the p-toluenesulfonyl chloride with the purity of 95 percent and the water content of about 4 percent and the concentrated sulfuric acid with the concentration of more than 90 percent.
The invention has the advantages that:
1. the product quality is obviously improved, and the raw material consumption is reduced. The by-products and colored impurities generated by the reaction aremostly left in the waste sulfuric acid mother liquor during the filtration, so that the target product has higher purity and tends to be white in color, and the product yield is improved due to the balanced movement of almost all solid phases separated from the mixture.
2. Because the separation of the reaction mixture does not adopt a hydrolysis method in ice water, the separation operation speed is accelerated during production, a large amount of hydrolysis heat is not released, the cold consumption is reduced during separation, and the purpose of energy conservation is achieved. Because no water is involved in the separation, the concentration of the by-product sulfuric acid is very high and can reach more than 90%.
3. The method also needs more excessive chlorosulfonic acid due to the reaction requirement, and after the dry separation is adopted, the excessive unreacted chlorosulfonic acid still remains in the mother liquor waste acid, thus providing conditions for recycling the chlorosulfonic acid.
The following is further detailed by way of example:
a2000-liter reactor is provided with a stirrer, a dropping funnel, a thermometer, a gas guiding device and a water absorption device for guiding gas, 7.5 moles of chlorosulfonic acid is firstly added into a flask, the flask is heated to about 50 ℃ under stirring, 2 moles of ammonium chloride are added into one portion, then the temperature of reaction contents is raised to 79-86 ℃, 5 moles of toluene are dropwise added, the temperature is reduced to 35-40 ℃ after the dropping is finished, the other half of chlorosulfonic acid is added, the reaction is continued for 1 hour, the temperature of the contents is reduced to 20-25 ℃ and is placed for 2 hours, at the moment, para-chlorine crystals are almost completely separated out, the crystals are filtered and separated out and washed, and ortho-position isomers are separated out, so that the final product of the para-toluenesulfonyl chloride with the content of more than 95 percent, the water content of about 40 percent, the melting point of about 65 ℃ and the yield (calculated by toluene) of 78 percent.
Claims (1)
1. A method for preparing p-toluenesulfonyl chloride comprises the steps of leading half chlorosulfonic acid required by reaction into a reactor, adding a salt to control the reaction temperature to be 60-100 ℃, dropwise adding toluene to enable the reaction material to be cooled to 10-40 ℃, adding the other half chlorosulfonic acid, and reacting for 1-4 hours; the molar ratio of the reaction materials is that the ratio of toluene to chlorosulfonic acid is 1: 2-4, and the ratio of toluene to salt is 1: 0.3-0.7; the method is characterized in that: fully crystallizing the para-position body and enlarging crystal particles in a crystallizer with the stirring speed of 2-50 r/min after the reaction is finished, wherein the crystallization temperature is-10-30 ℃, and the crystallization time is 1-8 hours; after full crystallization, the p-toluenesulfonyl chloride and the concentrated sulfuric acid with the concentration of more than 90 percent can be obtained by direct filtration and water washing.
Priority Applications (1)
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CN97101400A CN1049213C (en) | 1997-03-10 | 1997-03-10 | Process for producing p-toluenesulfonyl chloride |
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CN97101400A CN1049213C (en) | 1997-03-10 | 1997-03-10 | Process for producing p-toluenesulfonyl chloride |
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CN1163264A true CN1163264A (en) | 1997-10-29 |
CN1049213C CN1049213C (en) | 2000-02-09 |
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CN97101400A Expired - Fee Related CN1049213C (en) | 1997-03-10 | 1997-03-10 | Process for producing p-toluenesulfonyl chloride |
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Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN102627589A (en) * | 2012-04-05 | 2012-08-08 | 天津理工大学 | Method and technology for synthesizing and preparing 4-isopropylbenzenesulfonyl chloride through two steps |
CN102633696A (en) * | 2012-04-05 | 2012-08-15 | 天津理工大学 | Method and technology for preparing p-substituted alkyl benzene sulfonyl chloride by two-step synthesis |
CN102633687A (en) * | 2012-04-05 | 2012-08-15 | 天津理工大学 | Method and technology for preparing p-substituted alkyl benzene sulfonyl chloride |
Family Cites Families (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE1912956A1 (en) * | 1969-03-14 | 1970-09-24 | Hoechst Ag | Process for the preparation of p-toluenesulfonyl chloride |
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1997
- 1997-03-10 CN CN97101400A patent/CN1049213C/en not_active Expired - Fee Related
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN102627589A (en) * | 2012-04-05 | 2012-08-08 | 天津理工大学 | Method and technology for synthesizing and preparing 4-isopropylbenzenesulfonyl chloride through two steps |
CN102633696A (en) * | 2012-04-05 | 2012-08-15 | 天津理工大学 | Method and technology for preparing p-substituted alkyl benzene sulfonyl chloride by two-step synthesis |
CN102633687A (en) * | 2012-04-05 | 2012-08-15 | 天津理工大学 | Method and technology for preparing p-substituted alkyl benzene sulfonyl chloride |
CN102633687B (en) * | 2012-04-05 | 2016-06-08 | 天津瑞岭化工有限公司 | The preparation method of a kind of para-orientation alkylbenzene sulfonyl chloride and technique |
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CN1049213C (en) | 2000-02-09 |
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