The process of o-toluenesulfonamide oxidation closed-loop refining sugar includes two processes: o-toluenesulfonamide oxidation electrolysis and oxidant regeneration. It is obtained by adding o-toluenesulfonamide into sulfuric acid aqueous solution with cold anhydride as oxidant. The invention is characterized in that the concentration of sulfuric acid aqueous solution used in the oxidation process is 50-58%, the reaction temperature is 40-60 DEG C, and the reaction time is 8-65+/-0.2 hours.
Method and equipment for recovering raw materials in saccharin preparation process
The invention relates to the recovery of raw materials in the process of preparing saccharin (APM) from an aqueous process stream containing dissolved salts by a nanofiltration method. Specifically, each aqueous process stream or a combined stream of two or more such streams is subjected to nanofiltration using a composite membrane having a specific rejection rate for components and monovalent salts higher than 65,438+000 d, and raw materials in the retentate thus obtained are recovered by methods known in the art, or the retentate is not further treated. The invention also relates to a device for implementing the method.
In the process of preparing saccharin (APM), a method for recovering raw materials from an aqueous process stream containing dissolved salts is characterized in that each aqueous process stream or a combined stream of two or more such streams (with a salt content of at least 1 wt%) is subjected to nanofiltration treatment with a composite membrane, and the rejection rate of components with a molecular weight greater than 100D is 50-65430. For monovalent salts, the rejection rate is +20-40%, and the raw materials in the retentate thus obtained can be recovered by methods known in the art, or the retentate can be returned to the saccharin preparation process without further treatment.
The invention relate to a production method of saccharin sodium, which comprises that reaction step of amidation, Hoffman degradation and lipidation, diazotization, substitution, chlorination, ammoniation, acid precipitation, alkalization and decoloration, and then filtering, concentrating, crystallize and drying to obtain a finished product; Characterized in that the steps of acid precipitation and alkalization reaction mainly include: adding 15-30% sulfuric acid to precipitate insoluble matter; Adding toluene to make insoluble particles; Washing with water until the acid water is clear; Preparing edible sodium carbonate solution with the concentration of 10 ~ 30%, pumping acid water, and adding into insoluble colloidal particles; At the same time, the temperature is raised to 45-55 DEG C, and the pH value is 2.8-3.8; Stir for 5-65438+/-00 minutes until the solution is uniform and transparent, stop stirring, and stand for layering to obtain 20-25% o-sulfonyl benzoyl imine sodium solution. The process of acid precipitation and alkalization is a liquid reaction, with low temperature and non-volatile toluene, which reduces air pollution and improves the working environment of operators. The method is simple to operate and can effectively reduce labor intensity and production cost.
1. A production method of saccharin sodium includes amidation, Hoffman degradation and greasing, diazotization, substitution, chlorination, ammoniation, acid precipitation, alkalization and decoloration, and then the finished product is obtained through filtration, concentration, crystallization and drying. Characterized in that the steps of acid precipitation and alkalization are as follows: (1) ammoniation reaction to obtain ammoniated solution. (2) Add water to adjust the concentration of ammoniated solution and toluene washing solution to 1.05 ~ 1.06kg/m3, measure the volume of ammoniated solution, add 375 ~ 425 parts of toluene in proportion, and continue stirring at 18 ~. (3) adding 375-425 parts of sulfuric acid with the concentration of 15%-30%, stirring 10- 15 minutes, and measuring the pH value at 15-30℃. (4) the acid water rainbow is sucked into a settling tank at the lower part of the reaction kettle and discharged, the temperature is kept at15-25 DEG C, the acid water is stirred for 10-20 minutes, and the acid water is discharged while being continuously stirred; (5) repeatedly washing the insoluble colloidal particles with water until the chloride content in the washing water is less than or equal to 0.08%; (6) pumping the last washing water into a two-body metering box for reuse as pickling jacket water; (7) after the acid water is pumped out, 611100 parts of edible sodium carbonate solution with the concentration of10-30% is added to the insoluble colloidal particles, and the reaction kettle is closed for stirring, and the stirring is continued after decompression; (8) simultaneously heating the reaction kettle to 45-55 DEG C, completely neutralizing and dissolving insoluble colloidal particles and edible sodium carbonate solution through uniform stirring, and determining the pH value of the solution to be 2.8-3.8; (9) stirring for 5-65438+/-00 minutes until the solution is uniform and transparent, stopping stirring, standing and layering to obtain 20-25% o-sulfonyl benzoyl imine sodium solution; (10) Decolorization reaction was carried out according to the conventional method, and then the finished product was obtained by filtration, concentration, crystallization and drying.
References:
China patent: 8510165; 94 1 15733.4;