Method for treating toluene mother liquor in order to reducing wastes discharged during preparation of sodium dehydroacetate

A technology of sodium dehydroacetate and treatment method, which is applied in the field of toluene mother liquor treatment to reduce the discharge of sodium dehydroacetate preparation waste residue, which can solve the problems of aggravating the difficulty of solid waste and liquid waste treatment, a large amount of solid waste residue and waste liquid, and increased costs

Inactive Publication Date: 2019-07-05
经纬精细化工(南通)有限公司
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  • Abstract
  • Description
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Problems solved by technology

In the process of preparing dehydroacetic acid, a large amount of toluene mother liquor will be produced, which can usually be applied mechanically for 2-3 times, and after 2-3 times, it will not be able to continue to be applied mechanically because the amount of impurities contained is too large
In the prior art, the toluene solution, which cannot be applied mechanically, is usually treated by atmospheric distillation, which will generate a large amount of solid waste residue and waste liquid, aggravating the difficulty of solid waste and liquid waste treatment, and increasing the cost

Method used

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  • Method for treating toluene mother liquor in order to reducing wastes discharged during preparation of sodium dehydroacetate

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Embodiment Construction

[0019] Specific embodiments of the present invention will be further described below. It should be noted here that the descriptions of these embodiments are used to help understand the present invention, but are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below may be combined with each other as long as they do not constitute a conflict with each other.

[0020] This specific embodiment discloses a toluene mother liquor treatment method that reduces the discharge of sodium dehydroacetate preparation waste residue, and obtains fine sodium dehydroacetate through concentrated distillation, negative pressure distillation, coarse crystallization and fine treatment;

[0021] Concentrated distillation: Put 2-3 batches of toluene solution into the still, add lye to the still, and concentrate and distill;

[0022] Negative pressure distillation: Use negative pressure vacuum to c...

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Abstract

The invention discloses a method for treating a toluene mother liquor in order to reducing wastes discharged during preparation of sodium dehydroacetate. Fine sodium dehydroacetate is obtained by concentrating distillation, negative pressure distillation, coarse crystallization and fine treatment. The method has the following advantages: alkaline hydrolysis of organic impurities can be effectivelycarried out in the manner of alkali lye concentrating distillation and negative pressure distillation, small molecular organic impurities obtained after alkali hydrolysis can be effectively removed by decolorization and recrystallization, decolorizing is carried out to remove impurities in order to form a fine sodium dehydroacetate product, and the emission of solid wastes is effectively reduced.

Description

technical field [0001] The invention relates to a preparation process of sodium dehydroacetate, in particular to a method for treating toluene mother liquor which reduces the discharge of waste residue from preparation of sodium dehydroacetate. Background technique [0002] Sodium dehydroacetate is a safe anti-mold and anti-corrosion food preservative approved by the Food and Agriculture Organization of the United Nations (FAO) and the World Health Organization (WHO). The preparation of sodium dehydroacetate usually adopts the reaction of dehydroacetic acid and sodium hydroxide to generate the product. In the prior art, dehydroacetic acid is usually prepared by dimerization of diketene in an inert solvent in the presence of a catalyst or by ethyl acetoacetate under the action of sodium bicarbonate. In the process of preparing dehydroacetic acid, a large amount of toluene mother liquor will be produced, which can usually be applied mechanically for 2-3 times, and after 2-3 t...

Claims

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Application Information

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IPC IPC(8): C07D309/36
CPCC07D309/36
Inventor 陆群山赵海建何小军
Owner 经纬精细化工(南通)有限公司
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