Comparison of Production Process of Na Saccharin

There are many production processes of na saccharin, which can be divided into toluene method, phthalic anhydride method, o-toluidine method and phthalic anhydride disulfide method according to the main raw materials used in production.

The o-toluidine method is not suitable for industrial production because of its high cost and limited source. Due to the space obstacle in the structure of o-disulfide-benzoic acid, the esterification of o-disulfide with methanol needs to be carried out in a autoclave. The reaction conditions are relatively harsh, and the requirements for reaction equipment are too high, so only pilot test has been carried out, and industrial production has not been realized. Therefore, only toluene method and phthalic anhydride method are compared.

na saccharin yield

When chlorosulfonation of toluene with chlorosulfonic acid is carried out, nearly half of the by-products of p-toluenesulfonyl chloride are generated. The yield of o-toluenesulfonyl chloramine to o-toluenesulfonamide is only 75-78%. Therefore, the total yield of na saccharin produced by toluene method is less than 40%. Although there are various kinds of side reactions in the production process of phthalic anhydride method, the total yield can reach more than 80%, which is more than twice as high as that of toluene method, so phthalic anhydride method is better in terms of yield.

na saccharin quality

The intermediate product o-toluenesulfonamide is generated in the process of producing na saccharin by toluene method, and the insoluble saccharin is generated after oxidation and acid analysis of o-toluenesulfonamide. In the actual production process, the oxidation is often incomplete, and the unreacted o-toluenesulfonamide cannot be completely separated during separation. In addition, p-toluenesulfonamide still exists in the product, which has a great impact on the product quality, such as Europe and the United States. It is difficult to control the content of O (or P) toluenesulfonamide in na saccharin. There is no similar product in the production of phthalic anhydride, and the product quality is better than that of toluene.