Production method for secondary acid hydrolysis of dimethyl ester glyphoate acid

Abstract

The invention relates to a production method for secondary acid hydrolysis acid of dimethyl ester glyphoate acid. After condensation reacting dimethyl ester glyphoate acid, adding 31% of hydrochloric acid at twice in the condensed liquid, at first adding 45-75% of total hydrochloric acid, second, adding the remaining hydrochloric acid when the temperature reaches 105 DEG C. The invention can effectively solve the problems of insufficient production efficiency of hydrolysis kettle, higher energy consumption and low coefficient of recovery in the process of methanol recovery, enable the utilization capacity of hydrolysis kettle to be increased 25%, shorten hydrolysis time about 1 hour, and also improve 25-30% of yield of glyphoate acid when the production cost of glyphoate acid is lowered 5-10%.

Description

technical field [0001] The invention relates to an acid hydrolysis method in the production process of glyphosate acid by a dimethyl ester method, in particular to a method for producing glyphosate acid by secondary acid hydrolysis. Background technique [0002] Glyphosate is the most used total herbicide in the world, and with the promotion of genetically modified crops, glyphosate will play an increasingly important role in herbicides. [0003] The industrial production method of glyphosate acid mainly contains two kinds at present: IDA method and alkyl ester method, and IDA method is mainly produced with natural gas as starting material; Alkyl ester method has been disclosed in document DEOLSNO.P 2942898.6, and it is Put paraformaldehyde or formaldehyde in methanol solution with triethylamine as a catalyst, depolymerize at a certain temperature, add glycine for addition reaction, and then add dimethyl phosphite for condensation reaction to obtain the triethylamine salt o...

AI Technical Summary

Problems solved by technology

First of all, in the acid hydrolysis process, there is often the problem of insufficient production capacity of the hydrolysis tank

Because the methanol and the water in the hydrochloric acid added in the synthesis process and the hydrolysis process will be steamed out during the hydrolysis process, so when the end point of the hydrolysis is reached, there will be very little material in the hydrolysis tank, resulting in a decrease in the capacity of the hydrolysis tank. Less than fully utilized, while steam energy is wasted

Secondly, since the vapor phase product steamed out by hydrolysis contains a large amount of water, and at the same time, the water contains hydrogen chloride, so a large amount of liquid caustic needs to be consumed for neutralization, which increases the energy consumption in the process of recovering methanol, giving methanol and formazan The acetal separation process has increased the difficulty, the recovery rate of methanol is not ideal, and a large amount of methanol bottom liquid is alkaline, which also adds considerable pressure to sewage treatment

[0007] Specifically, in the acid hydrolysis process, at present, the added acid is added to the hydrolysis kettle at one time to raise the temperature. In this way, there is a problem in the early stage of hydrolysis, that is, part of the added hydrochloric acid does not participate in the reaction, but is heating up. A large amount of heat is consumed in the process; at the same time, because the hydrolysis reaction is an endothermic reaction, the heat is insufficient when the main reaction is carried out, which slows down the reaction speed, prolongs the reaction time, and consumes energy in vain; at the same time, due to all The acid is added to the hydrolysis kettle at one time, which makes the water content in the hydrolysis kettle too high, which leads to a slow rate of demethanolization and prolongs the time of the hydrolysis reaction. Higher temperature and longer heating time will cause a certain amount of hydrochloric acid to be volatilized and lost, thereby increasing the amount of hydrochloric acid fed into the hydrolysis, and also increasing the material consumption, energy consumption and processing difficulty of the subsequent process

In addition, in the acid methanol formed by the co-distillation of methanol and water, because the water content is too high (generally between 25% and 30%), and the acid methanol also contains HCl evaporated during the distillation process, so that In the subsequent rectification process of methanol, it needs to consume a large amount of liquid caustic soda to neutralize HCl, so that the ion concentration in methanol is greatly increased, so that the energy consumption and recovery efficiency in the methanol rectification process and subsequent sewage treatment have very adverse effects