Method for preparing 6-methyl-1,2,3-oxazine-4(3H)-ketone-2,2-dioxopotassium salt

Abstract

The method for preparing 6-methyl-1,2-3-oxathiazine-4-(3H)-keto-2,2-dioxopotassium salt includes the steps of acetoacetylation of aminosulfuryl fluoride by means of diketene, cyclopolymerization in the methyl alcohol solution of sodium hydroxide or potassium hydroxide and purification, in which the acetoacetylation step is implemented in the presence of alkali metal salt of organic weak acid, andunder the condition of that the product crude is potassium salt said purification step can be implemented by using alcohol water recrystallization method, and under the condition of that the product crude is other salt except for potassium salt said purification step can be implemented by using organic solvent extraction method and alcohol water recrystallization method.

Description

technical field [0001] The invention relates to a method for preparing 6-methyl-1,2,3-oxathiazin-4(3H)-one-2,2-dioxyl potassium salt. Background technique [0002] The sweetness of 6-methyl-1,2,3-oxathiazin-4(3H)-one-2,2-dioxy potassium salt (Acesulfamek, acesulfamek) is 200-250 times that of sucrose. It is an ideal artificial sweetener with safety, heat resistance, good taste, no metabolism and accumulation in the body, and very stable physical and chemical properties. There are many synthetic methods of acesulfame potassium. The method reviewed by Angemamete chamie in 1973 is mainly based on the reaction of chlorine or fluorosulfonyl isocyanate with acetoacetic acid, tert-butyl acetoacetic acid, acetone or benzyl propenyl ether to prepare acetoacetate. Aminosulfonyl chloride or fluorine is cyclized under the action of alkali to obtain acesulfame potassium, and the synthesis of its raw materials and intermediates is very difficult. In 1976, DE 2...

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Problems solved by technology

There are many synthetic methods of acesulfame potassium. The method reviewed by Angemamete chamie in 1973 is mainly based on the reaction of chlorine or fluorosulfonyl isocyanate with acetoacetic acid, tert-butyl acetoacetic acid, acetone or benzyl propenyl ether to prepare acetoacetate. Aminosulfonyl chloride or fluorine, and then cyclized under the action of alkali to obtain acesulfame potassium, the synthesis of its raw materials and intermediates is very difficult

In 1976, DE 2447201 reported another method for preparing acetoacetylsulfamoyl fluoride with sulfamoyl fluoride as raw material and diketene reflux reaction in benzene or chloroform, but because the reaction temperature was too high, there were too many side reactions and the yield was only 37-50%. In the same year, DE 24570132 reported a yield of 91% in the presence of triethylamine at 10-20°C, but the product was a brown oil, and it was difficult to purify acesulfame potassium after alkali cyclization.

In 1985, DE 3410233 reported the method of using the reaction in the presence of potassium carbonate instead. Although the product is solid, the purity of acesulfame potassium after cyclization is still poor

In 1985, DE 3410439 and DE 3410440 respectively reported that sulfamic acid and diketene were used as raw materials to prepare acetic acid acetamidosulfonate in the presence of triethylamine or to prepare acetoacetamide with diketene and ammonia, and then use SO3 A new method for preparing acesulfame potassium by cyclization. The raw materials of this method are easy to obtain and the reaction steps are relatively short. However, because the cyclization needs to be reacted at a low temperature below -30°C, and the by-product triethylamine sulfate pollution is not easy to handle, it is also Brings many problems to synthesis and production

In addition, no matter which method is used to prepare the crude acesulfame potassium, it must be purified by 100°C water recrystallization method. Due to the high solubility of acesulfame potassium in water, only 0.8-1 part of water can be used, not only hot filtration or activated carbon decolorization, etc. Difficult and requires multiple recrystallizations to achieve quality material, excessive product loss and difficult recovery of product from water

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