CN1657531A

CN1657531A - Process for treating production mother liquor of glyphosate

Info

Publication number: CN1657531A
Application number: CN 200510049067
Authority: CN
Inventors: 孔鑫明; 刘劭农; 刘德亮; 于游海; 李群浩
Original assignee: HANGZHOU JINFADA CHEMICAL INDUSTRY Co Ltd
Current assignee: JIANGXI JINLONG CHEMICAL CO., LTD.
Priority date: 2005-02-05
Filing date: 2005-02-05
Publication date: 2005-08-24
Anticipated expiration: 2025-02-05
Also published as: CN1308336C

Abstract

A process for treating the productive mother liquid of glyphosate includes such steps as proportionally adding ammonium dicarbonate, stirring while reaction, solid-liquid separation to obtain dicarbonate cake for cyclic use and filtrate, and using the filtrate to prepare the liquid glyphosate.

Description

Process for treating mother liquor in glyphosate production

Technical Field

The invention relates to a treatment process of glyphosate production mother liquor, in particular to a treatment process of glyphosate production mother liquor for preparing a glyphosate aqueous solution.

Background

The glyphosate is an internal absorption conduction type herbicide with the largest global sales and the fastest growth speed, and provides a new opportunity for the production of the glyphosate along with the successful development and popularization of glyphosate-resistant transgenic crops. There are two main synthetic modes for global glyphosate production, namely the IDA method, i.e. diethanolamine is used as a starting material and is commonly adopted by foreign companies such as Monsanto, USA, and the alkyl ester method is adopted by most domestic enterprises. The main raw materials for producing glyphosate acid by alkyl ester method are paraformaldehyde (formaldehyde), glycine, dimethyl phosphite, triethylamine, methanol and hydrochloric acid, wherein the depolymerization of paraformaldehyde uses triethylamine as catalyst, and after depolymerization, addition, condensation and hydrolysis reaction, glyphosate hydrochloride is generated, after removing solvent methanol and excessive hydrochloric acid, glyphosate is crystallized and separated out, filtration and washing are carried out, a filter cake is glyphosate acid, mother liquor and washing liquor (combined called mother liquor) contain triethylamine hydrochloride and 1-3% of glyphosate, phosphorous acid and glyphosate derivatives, the mother liquor obtained after triethylamine is neutralized and recovered by liquid alkali also contains sodium chloride generated by neutralizing hydrochloric acid by sodium hydroxide, the yield of the mother liquor is about 2-6 tons/raw powder, and the content of glyphosate is 1-3% without concentration. The existing mother liquor disposal method is as follows: the mother liquor is directly prepared into glyphosate water solution through physical concentration or without physical concentration, and the quality is poor due to more impurities; the other treatment is to discharge the mother liquor after treatment as sewage, and the COD value is as high as hundreds of thousands, and the treatment cost is extremely high because of the phosphorus contained, so the method is not basically adopted. At present, the mother liquor is mainly treated by preparing the aqueous solution, however, because the yield of the mother liquor is large, if the mother liquor is not concentrated, all the mother liquor is used for preparing the glyphosate aqueous solution, the market capacity is insufficient, and the economic benefit is not good; if the concentration technology is adopted, high concentration ratio cannot be obtained due to high impurity content in the mother liquor, excessive concentration is carried out, and the prepared glyphosate aqueous solution is easy to be turbid and crystallized. The process for producing glyphosate by trimethyl phosphite is similar.

Disclosure of Invention

In order to overcome the problems existing in the direct preparation of the glyphosate aqueous solution from the mother liquor, the invention aims to provide a process method for preparing a high-quality glyphosate aqueous solution by chemically treating the mother liquor generated in the production of glyphosate.

The glyphosate production mother liquor treatment process is characterized by comprising the following steps:

1) adding ammonium bicarbonate into the mother liquor at a weight ratio of ammonium bicarbonate to the mother liquor of 1: 0.5-8 at a temperature of 20-70 ℃, and stirring until the ammonium bicarbonate and the mother liquor react fully;

2) after the reaction is finished, carrying out solid-liquid separation treatment on the reaction mixture to obtain a sodium bicarbonate filter cake and a filtrate;

3) preparing a glyphosate aqueous solution by using the filtrate obtained in the step 2).

The process for treating the mother liquor in glyphosate production is characterized in that before the mother liquor is added with ammonium bicarbonate for reaction, concentration treatment is carried out firstly, namely the mother liquor is concentrated until sodium chloride is nearly saturated, then the mother liquor is cooled to 30-60 ℃, solid-liquid separation is carried out, and the supernatant is used in the step 1).

The glyphosate production mother liquor treatment process is characterized in that the weight ratio of ammonium bicarbonate to mother liquor is 1: 2-6, the reaction temperature is 30-60 ℃, the preferable ratio is 1: 3-5, and the reaction temperature is 40-50 ℃.

The treatment process of the glyphosate production mother liquor is characterized in that the filtrate obtained in the step 2) is used for preparing a glyphosate aqueous solution with the content of 10 percent.

The treatment process of the glyphosate production mother liquor is characterized in that the filtrate obtained in the step 2) is concentrated until the glyphosate content is 3-5%, and then 10% glyphosate aqueous solution is prepared.

According to the treatment process of the mother liquor in glyphosate production, sodium bicarbonate with lower solubility than sodium chloride is used, ammonium bicarbonate is added to fully react, sodium chloride is converted into sodium bicarbonate to precipitate, a large amount of sodium salt in the mother liquor can be removed, sodium ions in the mother liquor are reduced, ammonium ions are increased, the glyphosate content in the mother liquor is increased from 1-3% to 3-5%, the drug effect of the prepared aqueous solution is obviously improved, and the same effect can be achieved only by about 70% of the aqueous solution prepared from untreated mother liquor; the precipitate sodium bicarbonate separated in the glyphosate production mother liquor treatment process can directly replace liquid caustic soda in glyphosate production, and is used for acidity adjustment of methanol and methylal mixed liquor recovered by dealcoholization, addition of the liquid caustic soda in a deacidification process, adjustment of the pH value of a crystallization kettle and neutralization of triethylamine-containing mother liquor; thereby greatly reducing the dosage of the liquid caustic soda and reducing the production cost of the glyphosate. And the treatment process is simple and easy to implement, and has remarkable economic benefit.

Detailed Description

The preferred embodiments of the present invention are described in detail below.

The glyphosate production mother liquor treatment process comprises the following steps: recovering mother liquor generated after glyphosate crystallization separation by triethylamine, wherein sodium chloride in the mother liquor is not saturated, in order to reduce the amount of the mother liquor, the mother liquor is concentrated to be nearly saturated by the sodium chloride immediately after the triethylamine is evaporated, and then the mother liquor is cooled to 30-60 ℃ to be crystallized and separated to remove the sodium chloride; then, adding ammonium bicarbonate into the mother liquor, wherein the weight ratio of the added ammonium bicarbonate to the mother liquor is 1: 3-5, stirring at 40-50 ℃ until full reaction, wherein the solubility of the sodium bicarbonate is less than that of sodium chloride, so that double decomposition reaction occurs between the added ammonium bicarbonate and the mother liquor, the sodium bicarbonate precipitates out, and in order to accelerate the reaction speed, the ammonium bicarbonate can be crushed, and the reaction is as follows:

the mother liquor generated after the glyphosate crystallization separation can also be directly subjected to the next process step without recycling triethylamine, the test values of the weight ratio of the ammonium bicarbonate to the mother liquor are selected from 1: 3, 1: 4 and 1: 5, the temperature is selected from 40 ℃, 45 ℃ and 50 ℃, and after the reaction is finished, solid-liquid separation is carried out by using the modes of sedimentation separation, centrifugal separation, vacuum suction filtration and the like. When the content of glyphosate in the separated mother liquor reaches 3-5%, adding glyphosate raw powder into the mother liquor to prepare a 10% glyphosate aqueous solution; on the other hand, if the glyphosate content in the separated mother liquor is less than 3%, concentrating the mother liquor until the glyphosate content is 3-5%, and then adding glyphosate raw powder to prepare a 10% glyphosate aqueous solution. Because the sodium ions in the treated mother liquor are reduced and the ammonium ions are increased, the drug effect of the aqueous solution is obviously improved, and the same effect can be achieved only by about 70 percent of the original dosage.

The precipitate sodium bicarbonate obtained after mother liquor treatmentcan directly replace liquid caustic soda in glyphosate production, and is used for acidity adjustment of methanol and methylal mixed liquor recovered by dealcoholization; adding liquid alkali in the deacidification process; adjusting the pH value of the crystallization kettle; neutralizing the triethylamine-containing mother liquor. The sodium bicarbonate replaces liquid caustic soda, so that the dosage of the liquid caustic soda can be reduced, and the production cost of the glyphosate is greatly reduced.

Claims

1. The glyphosate production mother liquor treatment process is characterized by comprising the following steps:

2. The process for treating the mother liquor generated in the glyphosate production according to claim 1, wherein before the mother liquor is added with ammonium bicarbonate for reaction, concentration treatment is carried out, namely the mother liquor is concentrated until sodium chloride is nearly saturated, then the mother liquor is cooled to 30-60 ℃, solid-liquid separation is carried out, and the supernatant is used in the step 1).

3. The process of claim 1, wherein the solid-liquid separation in step 2)is settling separation, centrifugal separation or vacuum suction filtration.

4. The process for treating the mother liquor generated in the glyphosate production according to claim 1 or 2, wherein the weight ratio of the ammonium bicarbonate to the mother liquor is 1: 2-6, and the reaction temperature is 30-60 ℃.

5. The process for treating the mother liquor generated in the glyphosate production according to claim 1 or 2, wherein the weight ratio of the ammonium bicarbonate to the mother liquor is 1: 3-5, and the reaction temperature is 40-50 ℃.

6. The process of claim 1, wherein the filtrate obtained in step 2) is used to prepare aqueous glyphosate solution with a concentration of 10%.

7. The process for treating the mother liquor in glyphosate production according to claim 1 or 4, wherein the filtrate obtained in step 2) is concentrated to a glyphosate content of 3-5%, and then prepared into a 10% glyphosate aqueous solution.