A kind of preparation method of acesulfame potassium

Abstract

The invention relates to a preparation method of acesulfame potassium. Including the following steps: (1) preparation of acetoacetamido-N-sulfonyl methyl ester: dissolving methyl sulfamate in chlorinated hydrocarbon solvent, under the catalysis of strong basic macroporous resin, reacting with diketene to generate Intermediate acetoacetamido-N-sulfonyl methyl ester; (2) preparation of acesulfame potassium: acetoacetamido-N-sulfonyl methyl ester undergoes a ring closure reaction under the action of a copper pyridine complex catalyst, and simultaneously passes the reaction Rectification removes by-product methanol; then KOH treatment to get acesulfame potassium. Compared with the existing production process, the use of copper pyridine complexes instead of strong acid catalysts in the cyclization process significantly reduces the occurrence of polymerization side reactions of intermediates and improves product yields. Also avoid triethylamine and SO 3 , greatly reducing the generation of waste acid and waste water.

Description

technical field [0001] The invention relates to a method for preparing a sweetener, in particular to a method for preparing acesulfame-K. Background technique [0002] Acesulfame potassium (acesulfame potassium), also known as A-K sugar, has been allowed as a low-calorie sweetener since 1988. It is a synthetic sweetener with a taste similar to sucrose, 200 times sweeter than sucrose, and has a synergistic sweetening effect when used with other sweeteners. It sweetens quickly, has good thermal stability, and can be excreted through the human digestive system without changing, so it has no calories. [0003] The synthesis route of acesulfame potassium can be divided into acetoacetamide method and diketene method according to different starting materials, the latter is relatively cheap and has cost advantages. [0004] In the existing acesulfame potassium production process, most manufacturers adopt the diketene-sulfur trioxide method, which uses sulfamic acid and diketene as...

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Problems solved by technology

The raw material of this route is easy to get, but there are significant disadvantages: 1) the cyclization process needs to use an excessive amount of SO 3 , a large amount of waste acid is generated after hydrolysis, an average of 20 tons of waste acid is generated per ton of product, and the pressure on environmental protection is high; 2) SO 3 It is a strong acid, which will cause the double bond polymerization of the intermediate in the process of catalytic ring closure, so that the reaction yield is lower than 82%. In the reaction process, an equal amount of triethylamine is used as a sulfonic acid group protecting agent, which leads to an increase in raw material cost. Although there is a patent (CN101157666A) to report that triethylamine can be recovered by distillation+rectification, it increases the cost of energy consumption and processing equipment, and the odor of triethylamine in the recovery process is difficult to control

[0008] Patent CN1092066A reports the use of substituted phenyl sulfamate to replace sulfamoyl fluoride, but the synthesis of raw material substituted phenyl sulfamate requires the use of sodium amide or azide, the process is complicated and the safety hazard is great, making it difficult to realize the industrial change

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