Method for treating carboxylic acid-containing DMF in sucralose production

A technology of sucralose and processing method, which is applied in the field of food additives, can solve the problems of DMF decomposition, DMF loss, and difficult-to-handle solid salt slag, and achieve the effects of reducing operating temperature, avoiding decomposition, and simple process

Active Publication Date: 2020-08-25
ANHUI JINGHE IND
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The existing process is mainly to neutralize the acidic DMF solution by directly adding alkali. The disadvantage of this process is that it will cause DMF to decompose under stro

Method used

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  • Method for treating carboxylic acid-containing DMF in sucralose production

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0022] like figure 1 As shown, the acidic DMF containing acetic acid: 20wt%, DMF: 80wt% discharged from the bottom of the deacidification tower in the sucralose DMF recovery section is added to the preliminary evaporator, and 3% sodium hydroxide is added at the same time. Distillation and condensation (-0.098 MPa, 60-100℃) to obtain colorless and transparent DMF containing acetic acid.

[0023] Add the above DMF containing acetic acid into the neutralization evaporator (the neutralization evaporator is a kind of equipment with stirring and automatic discharge, which can realize the three functions of neutralization, evaporation concentration and solid discharge), and add equimolar ratio Sodium hydroxide makes the pH value of the reaction mixture to 7.0. After neutralizing the reactant, the material is water, DMF and sodium acetate, and then evaporates and concentrates (-0.098MPa, 60-100°C), and condenses the gas phase (the circulating water is condensed to 30- 50°C) to obtain...

Embodiment 2

[0029] Add the acidic DMF containing acetic acid: 15wt% and DMF: 85wt% discharged from the bottom of the deacidification tower in the sucralose DMF recovery section to the neutralization evaporator, and add 5% sodium hydroxide at the same time, distill and condense the colorless and transparent DMF containing acetic acid is added to the neutralization reaction evaporator, and sodium hydroxide in equimolar ratio is added to make the pH value of the reaction mixture reach 7.0. After neutralizing the reactant, the material is water, DMF and sodium acetate, and then evaporated and concentrated, and condensed in the gas phase To obtain acid-free DMF, the evaporator is high-purity sodium acetate; then the acid-free DMF obtained by gas phase condensation is sent to the rectification tower, and the top of the rectification tower is obtained including water, DMF and dimethylamine. , A bottom mixture comprising DMF, DMAC, and tetramethylurea was obtained at the bottom of the rectificatio...

Embodiment 3

[0032] Add the acidic DMF containing acetic acid: 18wt% and DMF: 82wt% discharged from the bottom of the deacidification tower in the sucralose DMF recovery section to the neutralization evaporator, and add 4% sodium hydroxide at the same time, distill and condense the colorless and transparent DMF containing acetic acid is added to the neutralization reaction evaporator, and sodium hydroxide in equimolar ratio is added to make the pH value of the reaction mixture reach 7.0. After neutralizing the reactant, the material is water, DMF and sodium acetate, and then evaporated and concentrated, and condensed in the gas phase To obtain acid-free DMF, the evaporator is high-purity sodium acetate; then the acid-free DMF obtained by gas phase condensation is sent to the rectification tower, and the top of the rectification tower is obtained including water, DMF and dimethylamine. , A bottom mixture comprising DMF, DMAC, and tetramethylurea was obtained at the bottom of the rectificatio...

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Abstract

The invention relates to a method for treating carboxylic acid-containing DMF in sucralose production. The method comprises the following steps of: a, adding a small amount of sodium hydroxide into carboxylic acid-containing DMF recovered in sucralose production so as to enable the sodium hydroxide to react with the carboxylic acid-containing DMF, performing evaporating and condensing to obtain amixture containing carboxylic acid, DMF, DMA and DMAC; b, adding sodium hydroxide with an equal molar ratio into the mixture for neutralization reaction, evaporating and concentrating a reaction solution to obtain a white sodium acetate fiinshed product, and condensing evaporated gas to obtain a DMF solution without carboxylic acid; c, conveying the DMF solution without carboxylic acid into a first rectifying tower for distillation, carrying out gas-phase condensation at the top of the tower to obtain a water-containing DMF mixture, and obtaining a mixture of DMAC, tetramethylurea and impurities at the bottom of the tower; d, dehydrating the water-containing DMF mixture, and carrying out secondary rectification to obtain high-purity DMF; and e, rectifying the mixture of the bottom of the first rectifying tower again to obtain DMAC and residual liquid containing DMAC and tetramethylurea. The method has the advantages of simple process and high DMF recovery efficiency, and can avoid thegeneration of solid salt slag in traditional processes, reduce the production cost, and reduce the pollution.

Description

technical field [0001] The invention belongs to the field of food additives in chemical technology, and in particular relates to a treatment method for carboxylic acid-containing DMF in the production of converted sucralose. Background technique [0002] Sucralose is a fresh sweetener, its sweetness is 600-800 times that of sucrose, and its sweetness is similar to that of sucrose. Sucralose is not absorbed by the human body, has no bioaccumulation, and has high safety. The sucrose industry developed rapidly, the number of production enterprises gradually increased, and the output continued to increase. The esterification and chlorination process in the production process of sucralose uses a large amount of DMF as a solvent. Since the recovered DMF contains a certain amount of water and acetic acid, it is necessary to carry out rectification, dehydration and deacidification of DMF by rectification, and then return it to esterification and chlorination. During the dehydration...

Claims

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Application Information

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IPC IPC(8): C07C231/24C07C233/03C07C51/42C07C53/10C07C51/44C07C51/43
CPCC07C231/24C07C51/42C07C51/44C07C51/43C07C233/03C07C53/10Y02P20/10
Inventor 许传久张正颂李广馨罗艺飞
Owner ANHUI JINGHE IND
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