CN114736126A

CN114736126A - Method for recovering dimethylamine from sucralose MVR mother liquor

Info

Publication number: CN114736126A
Application number: CN202210315761.0A
Authority: CN
Inventors: 张正颂; 陈永乐; 王汉之
Original assignee: Anhui Jinhe Industrial Co Ltd
Current assignee: Anhui Jinhe Industrial Co Ltd
Priority date: 2022-03-29
Filing date: 2022-03-29
Publication date: 2022-07-12

Abstract

The invention relates to a method for recovering dimethylamine from a sucralose MVR mother solution, which is characterized by comprising the following steps: (1) adding liquid potassium hydroxide into the sucralose MVR mother liquor for alkaline hydrolysis, controlling the adding amount to be 35-50% of the mass of the MVR mother liquor, and reacting at 110-130 ℃ for 12-24 hours; (2) evaporating the mother liquor after alkaline hydrolysis under negative pressure, controlling the vacuum degree to be minus 10 to minus 5kPa and the temperature to be 90 to 110 ℃, refluxing condensed water, and recovering dimethylamine and ammonia obtained by decomposition; then preparing mixed ammonia water by a water absorption mode, sending the mixed ammonia water to a dimethylamine rectification recovery device for refining, and separating to obtain a liquid dimethylamine main product and a 20% ammonia water byproduct; (3) adjusting the pH of the recovered mother liquor to 6-8 by using hydrochloric acid; adding active carbon, and performing filter pressing to obtain filtrate which can be used as a macroelement organic liquid and used as a production raw material of the organic fertilizer. The invention has the beneficial effects that: recovering dimethylamine from the MVR mother liquor, and obtaining byproducts of ammonia water and organic fertilizer raw materials which are rich in potassium elements and organic matters; the method is simple and efficient, and has industrial application value.

Description

Method for recovering dimethylamine from sucralose MVR mother liquor

Technical Field

The invention belongs to the technical field of fine chemical engineering, and relates to a method for recovering dimethylamine from a sucralose MVR mother liquor.

Background

Sucralose, commonly called sucralose, is white crystalline powder or granules in appearance, has sweetness about 600 times of sucrose, is used as a new generation sweetener, is the only one 'zero calorie' sugar which takes sucrose as a raw material, has pure taste, does not participate in human metabolism, and can be used by patients with diabetes, cardiovascular and cerebrovascular diseases and the old. The product has the characteristics of high sweetness, no calorie, good stability, high safety and the like, and is widely applied to a plurality of fields of foods, beverages, daily chemicals, medicines and the like.

In the production process of the sucralose, various solvents such as DMF, trichloroethane, ethyl acetate, butyl acetate, methanol and the like are required to be used, and the use amount is large, the application times are many, and the solvent decomposition loss is not little. For example, DMF is used in large amount in sucralose production, part of DMF is decomposed into dimethylamine and formic acid in the recovery process, and dimethylamine is easy to react with HCl in the system to generate corresponding dimethylamine hydrochloride which is dissolved in wastewater. And finally enriching in mother liquor generated in an MVR evaporation system through multi-stage treatment of wastewater. In recent years, the price of dimethylamine is high, and exceeds ten thousand yuan per ton, so that the dimethylamine has high recovery value, and the research on the recovery of dimethylamine in the sucralose MVR mother liquor is less at present.

Disclosure of Invention

The invention aims to make up the defects of the prior art and efficiently utilize resources, and provides a method for recovering dimethylamine from a sucralose MVR mother solution; the dimethylamine hydrochloride in the MVR mother liquor is decomposed through strong basicity of KOH to generate corresponding dimethylamine and potassium chloride; and recovering dimethylamine by evaporation and absorption, and obtaining byproducts of ammonia water and organic fertilizer raw materials rich in potassium and organic matters.

In order to achieve the purpose, the technical scheme adopted by the invention is as follows:

a method for recovering dimethylamine from a sucralose MVR mother liquor is characterized by comprising the following steps:

(1) an alkaline hydrolysis step: adding liquid potassium hydroxide into the sucralose MVR mother liquor for alkaline hydrolysis, controlling the addition amount of the liquid potassium hydroxide to be 35-50% of the mass of the MVR mother liquor, and reacting at 110-130 ℃ for 12-24 hours; utilizing strong basicity of the product to decompose dimethylamine hydrochloride in the mother solution into dimethylamine and potassium chloride; DMF is decomposed into dimethylamine, potassium formate and the like;

(2) evaporation deamination and amine refining: evaporating the mother liquor after alkaline hydrolysis under negative pressure, controlling the vacuum degree to be-10 to-5 kPa and the temperature to be 90-110 ℃, refluxing condensed water, and recovering dimethylamine and ammonia obtained by decomposition; then mixed ammonia water (amine) is prepared by a water absorption mode, and the mixed ammonia water (amine) is sent to a dimethylamine rectification recovery device for refining and separated to obtain a liquid dimethylamine main product and a 20% ammonia water byproduct;

(3) neutralizing and filter pressing: the recovered mother liquor is alkaline, and then hydrochloric acid is used for neutralization, so that the pH value is adjusted to 6-8; then adding powdered activated carbon, press-filtering, separating insoluble solids such as tar and solid particles in the system, and using the obtained filtrate as a macroelement organic liquid as a production raw material of the organic fertilizer.

Further, the sucralose MVR mother liquor comprises the following main components: 23-30% of organic matter, 20-30% of dimethylamine hydrochloride, 1.5-3.0% of ammonium chloride, 1.4-3.0% of dimethylamine sulfate, 35-50% of water and 6-8% of other impurities.

Further, the concentration of the liquid potassium hydroxide in the step (1) is 45-50%.

Further, the time of negative pressure evaporation in the step (2) is 8-12 h.

Further, the adding amount of the activated carbon in the step (3) is 5-8%.

The invention has the beneficial effects that: recovering dimethylamine from MVR mother liquor rich in a large amount of dimethylamine hydrochloride and carbohydrate organic matters, and obtaining a byproduct ammonia water and an organic fertilizer raw material rich in potassium elements and organic matters; the method is simple and efficient, and has high industrial application value.

Drawings

FIG. 1 is a schematic diagram of a process for recovering dimethylamine from the MVR mother liquor of sucralose.

Detailed Description

Exemplary embodiments of the present application will be described in more detail below; while exemplary embodiments of the present application have been illustrated and described, it should be understood that the present application may be embodied in various forms and should not be limited by the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.

With reference to fig. 1, the specific implementation steps of a method for recovering dimethylamine from sucralose MVR mother liquor are as follows:

example 1

(1) Accurately measuring 1000mL of sucralose MVR mother liquor (the density is 1.10 g/mL), wherein the specific components are shown in Table 1, slowly dropwise adding 392g of 48% KOH solution, heating to 120 ℃ after dropwise adding, and continuously reacting for 22 hours;

(2) after the reaction is finished, vacuumizing, wherein the vacuum degree is-8 Kpa, the temperature is 100 ℃, and the reaction lasts for 8 hours;

(3) then adding pure water into the mother liquor, fixing the volume of the mother liquor to 1000mL, and then adding 35% hydrochloric acid to adjust the pH value to 7;

(4) after the adjustment is finished, adding 50g of powdered activated carbon, uniformly stirring, and carrying out filter pressing to obtain a filtrate; and analyzing the ammonia nitrogen content in the filtrate to be 0.03g/L (the basis for judging the conversion of the dimethylamine hydrochloride and the ammonium chloride).

Example 2

(1) Accurately measuring 2000mL of sucralose MVR mother liquor (the density is 1.12 g/mL), wherein the specific components are shown in Table 2, slowly dropwise adding 830g of 48% KOH solution, heating to 110 ℃ after dropwise adding, and continuously reacting for 24 hours;

(2) after the reaction is finished, vacuumizing, wherein the vacuum degree is-10 Kpa, the temperature is 90 ℃, and the reaction lasts for 10 hours;

(3) then adding pure water into the mother liquor, fixing the volume of the mother liquor to 2000mL, and then adding 35% hydrochloric acid to adjust the pH value to 6;

(4) after the adjustment is finished, adding 120g of powdered activated carbon, uniformly stirring, and carrying out filter pressing to obtain a filtrate; the content of ammonia nitrogen in the analysis filtrate is 0.04 g/L.

Example 3

(1) Accurately measuring 1000mL of sucralose MVR mother liquor (the density is 1.10 g/mL), wherein the specific components are shown in Table 3, slowly dropwise adding 530g of 48% KOH solution, heating to 130 ℃ after dropwise adding, and continuously reacting for 20 hours;

(2) after the reaction is finished, vacuumizing, wherein the vacuum degree is-5 Kpa, the temperature is 110 ℃, and the reaction lasts for 12 hours;

(3) then adding pure water into the mother liquor, fixing the volume of the mother liquor to 1000mL, and then adding 35% hydrochloric acid to adjust the pH value to 8;

(3) after the adjustment is finished, adding 80g of powdered activated carbon, uniformly stirring, and carrying out filter pressing to obtain a filtrate; the content of ammonia nitrogen in the analysis filtrate is 0.06 g/L.

Claims

1. A method for recovering dimethylamine from a sucralose MVR mother liquor is characterized by comprising the following steps:

(2) evaporation deamination and amine refining: carrying out negative pressure evaporation on the mother liquor after alkaline hydrolysis, controlling the vacuum degree to be minus 10 to minus 5kPa and the temperature to be 90 to 110 ℃, refluxing condensed water, and recovering dimethylamine and ammonia obtained by decomposition; then preparing mixed ammonia water in a water absorption mode, sending the mixed ammonia water to a dimethylamine rectification recovery device for refining, and separating to obtain a liquid dimethylamine main product and a 20% ammonia water byproduct;

(3) neutralizing and filter pressing: the recovered mother liquor is alkaline, and then hydrochloric acid is used for neutralization, so that the pH value is adjusted to 6-8; then adding active carbon, press filtering, separating insoluble solids such as tar, solid particles and the like in the system, and taking the obtained filtrate as a macroelement organic liquid as a production raw material of the organic fertilizer.

2. The process of claim 1 for recovering dimethylamine from the sucralose MVR mother liquor, wherein: the sucralose MVR mother liquor comprises the following main components: 23-30% of organic matter, 20-30% of dimethylamine hydrochloride, 1.5-3.0% of ammonium chloride, 1.4-3.0% of dimethylamine sulfate, 35-50% of water and 6-8% of other impurities.

3. The process of claim 1 for recovering dimethylamine from the sucralose MVR mother liquor, wherein: the concentration of the liquid potassium hydroxide in the step (1) is 45-50%.

4. The process of claim 1 for recovering dimethylamine from the sucralose MVR mother liquor, wherein: and (3) the time of negative pressure evaporation in the step (2) is 8-12 h.

5. The process of claim 1 or 2 or 3 or 4 for recovering dimethylamine from the sucralose MVR mother liquor, wherein: the adding amount of the activated carbon in the step (3) is 5-8%.