New process for clean production of pmida and cyclic utilization of byproducts

Abstract

The invention relates to a new process for clean production of pmida and cyclic utilization of byproducts. According to the new process, iminodiacetonitrile serves as a main raw material, ammonia gas or / and a regenerated diacid monosodium salt are recovered by an alkaline hydrolysis or acid hydrolysis and alkaline hydrolysis coordinating process and an ammonium salt added and heating deamination double decomposition reaction, a qualified sodium chloride byproduct is precipitated and separated through the direct hydrolysis of pmida mother liquor and the common-ion effect of hydrogen chloride, acidic mother liquor can be cyclically applied mechanically, mother liquor, mother liquor, which cannot be applied mechanically, and washing water can be completely precipitated and separated through adding calcium hydroxide, raw materials and products can be regenerated from precipitates by an aqueous solution of acid or alkali, the precipitates are applied mechanically or are used for independently synthesizing the pmida, and regenerated calcium hydroxide can be repeatedly applied mechanically. According to the new process, the clean production of the pmida and the cyclic and high-added-value utilization of the byproducts can be realized.

Description

technical field [0001] The invention relates to a clean production process of a glyphosate intermediate, diglyphosate, and belongs to the technical field of pesticides and fine chemicals. Background technique [0002] Diglyphosate is an intermediate for the preparation of glyphosate, a broad-spectrum herbicide with the largest global consumption. The chemical name of glyphosate is N-phosphonomethylglycine. The control of deep-rooted malignant weeds is very effective. In recent years, the sales volume has gradually increased. It ranks first among the 50 largest pesticide varieties in the world. The market size exceeds 10 billion US dollars. It has been registered and widely used in more than 130 countries around the world. [0003] The industrial production of bisglyphosate is obtained by using iminodiacetic acid, phosphorous acid and formaldehyde under the catalysis of hydrochloric acid, heating to reflux condensation, cooling and crystallization to separate. Diglyphosate h...

AI Technical Summary

Problems solved by technology

This method has too many times of solid-liquid separation, and the yield of diacid is only about 80%. A large amount of diacid waste water containing salt is concentrated and desalted, and the method of regeneration of evaporative condensate is used. The energy consumption is high, and the quality of salt is poor, so it is difficult to use.

[0007] At present, most enterprises adopt the method of desalting concentrated diglyphosate wastewater and regenerating evaporative condensate, but the existence of formaldehyde leads to biochemical difficulties, and there are problems such as high energy consumption, poor quality of waste salt, and difficulty in utilization.

There is no good method for the treatment of wastewater and mother liquor produced in the dinitrile process. Although there are membrane technologies for wastewater treatment and desalination processes, there are large initial investment, frequent clogging and damage of membranes, short service life, and high operating costs. The high problem has not yet been well resolved

This process saves the consumption of alkali and hydrochloric acid, but increases the consumption of ammonia and the refining of crude products. The process is longer and the investment is relatively large.

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