Production of bisphenol A by sulfuric acid process

Sulfuric acid is the traditional production method of bisphenol A In this method, 73-74% sulfuric acid is used as catalyst According to the ratio of phenol: acetone: acid, 2:1:6, phenol and sulfuric acid are put into the reaction box, toluene is added as reaction medium, the temperature is reduced to below 30 ℃ under agitation, and then a proper amount of cocatalyst is added, usually mercaptoacetic acid, whose main purpose is to shorten the reaction period, reduce the amount of sulfuric acid, improve the product quality and Conversion rate to reduce production costs Then add acetone drop, the reaction temperature is controlled at 35-40 ℃, the reaction time is 4-6 hours, the acid solution is removed by filtration, the filter cake is washed by water, neutralized by sodium carbonate and centrifuged to get the finished product, the yield is 82-85% Sulfuric acid process is characterized by less equipment and simple process, but there are many by-products generated in the synthesis of bisphenol A, such as o-bisphenol, o-p-bisphenol, triphenol, chromic concealment and other condensates Therefore, the product quality of this process is poor, the material consumption quota is high, the labor intensity is high, and the three wastes are more, so the treatment is particularly difficult Bisphenol A is mainly used in epoxy resin and polycarbonate They have high purity requirements Bisphenol A for epoxy resin requires a purity of more than 95%, while bisphenol A for polycarbonate requires a purity of more than 99.5% They have strict restrictions on chromaticity and impurities Bisphenol A products produced by sulfuric acid method must be refined before they can be used in both The common purification methods of bisphenol A products are recrystallization, adduct purification and solvent extraction Sulfuric acid method is still the main production method of bisphenol A in China, but it has been phased out as early as 1960s in developed countries