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Prepn process of 2,6-dichloroaniline

A technology of diphenylurea and disulfonic acid, applied in 2 fields, can solve problems affecting product yield and purity, large water vapor consumption, poor reaction selectivity, etc., and achieve low raw material prices, low investment intensity and cost, and conditions mild effect

Inactive Publication Date: 2007-07-25
谢建伟 +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The disadvantage is that in the sulfonation process, the reaction selectivity is poor, and the by-products such as 2,4-dichloroaniline and 2,4,6-trichloroaniline are easily generated by ortho-position sulfonation, which affects the yield and purity of the product; in addition, 98% sulfuric acid The molar consumption of diphenyl urea is nearly 800% of that of diphenyl urea. There is a lot of sulfuric acid waste liquid, and the equipment is corroded; because sulfuric acid is difficult to separate, it also causes the subsequent chlorination step to be diluted with a large amount of water, which brings water vapor consumption to the steaming process. Disadvantages such as large quantity

Method used

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  • Prepn process of 2,6-dichloroaniline
  • Prepn process of 2,6-dichloroaniline
  • Prepn process of 2,6-dichloroaniline

Examples

Experimental program
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Effect test

Embodiment 1

[0038] Add 20g of p-aminobenzenesulfonic acid and 300ml of water into a 250ml four-neck flask, stir, add 6ml of triethylamine, add 6.0g of bis(trichloromethyl)carbonate solid powder, heat up to 75°C, react for 6h, and the reaction ends After standing for cooling, the mixture was filtered under reduced pressure to obtain a light yellow liquid. Add 30ml of 37% HCl, feed 11.5g of chlorine gas within 5 hours, control the temperature at about 40°C, cool down after stirring for 1h, add 15ml of 98% HCl 2 SO 4 , heated to 130°C for 6 hours, then heated to 160°C for 5 hours. 14.5 g of 2,6-dichloroaniline was obtained by rectification, and the total yield of 2,6-dichloroaniline was 76% based on p-aminobenzenesulfonic acid.

Embodiment 2

[0040] Add 10g of p-aminobenzenesulfonic acid and 140ml of water into a 250ml four-necked flask, stir, add 5ml of triethylamine, and add 40ml of bis(trichloromethyl)carbonate toluene solution (containing 6.0g of bis(trichloromethyl)carbonate) to the reaction solution within 1h. Chloromethyl)carbonate), control the temperature to 80°C, and react for 5 hours. After the reaction, the mixed solution is filtered under reduced pressure. The filtrate is stratified, and the filtrate is separated to obtain a light yellow liquid. Add 22ml of 37% HCl, introduce 4.5g of chlorine gas within 4 hours, control the temperature at about 30°C, stir for 1 hour and then cool down, add 10ml of 98% HCl 2 SO 4, heated to 135° C. for 6 hours, then heated to 165° C. for 5 hours, and rectified to obtain 6.8 g of 2,6-dichloroaniline. Based on p-aminobenzenesulfonic acid, the total yield of 2,6-dichloroaniline was 72%.

Embodiment 3

[0042] According to Example 1, without adding triethylamine, the reaction temperature of the first step is 50° C., and the reaction time is 7 hours. When chlorination, add 150ml of methanol, pass through 9.2g of chlorine gas at 40°C, evaporate the solvent, add 20ml of 70% H 2 SO 4 , heated to 130° C. for 5 hours, then heated to 162° C. for 3 hours, and rectified to obtain 13.6 g of 2,6-dichloroaniline. The total yield of 2,6-dichloroaniline was 72% based on p-aminobenzenesulfonic acid.

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Abstract

The preparation process of 2, 6-dichloroaniline includes the reaction of p-amino benzenesulfonic acid or its derivative as main material with di(trichloromethyl) carbonate to produce diphenylurea-4, 4'-disulfonic acid or its dereivative; on-ring chlorination and hydrolysis; and final rectification or distillation to obtain high purity 2, 6-dichloroaniline product. Compared with available preparation process, the present invention has the features of low material cost, high reaction selectivity, mild condition, high total yield, low production cost and being suitable for industrial production.

Description

technical field [0001] The invention belongs to a preparation method of 2,6-dichloroaniline. Background technique [0002] 2,6-Dichloroaniline is mainly used as an intermediate in the synthesis of medicines and pesticides. 2,6-dichloroaniline (2,6-Dichloroaniline, hereinafter referred to as: 2,6-DCA) is the intermediate of the third generation non-steroidal powerful anti-inflammatory analgesic diclofenac (diclofenac sodium); It is an important intermediate of 2.3.4-trifluoronitrobenzene, the starting material of ofloxacin and lomefloxacin, a new high-efficiency and broad-spectrum anti-infective drug, and is the basic product of the third generation of fluoroquinolone acid drugs. In recent years, with the rise of new quinolone antibacterial drugs, especially the production and marketing of ofloxacin and lomefloxacin, the research on the production technology of the starting material 2,6-DCA has progressed rapidly, and the annual demand has also continued to increase. Theref...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C209/68C07C209/74C07C211/52
Inventor 谢建伟苏为科
Owner 谢建伟