Study On The Synthesis Technology Of Sucralose

In this paper, the synthesis method and process of sucralose were studied asfollowing work:Two methods were used to prepare sucrose-6-acetate, one was esterified withtrimethyl orthoacetate, another one with dibutyltin oxide and acetic anhydride.Comparing the two methods, the merits of the latter one were sucrose-6-acetate can beachieved in high yield with less by-products by simple separation, and dibutyltinoxide can by recovered and reused. It was a method with more efficiency tosynthesize sucrose-6-acetate. Its disadvantages are higher requirements with deviceand higher energy consumption.With mono-factor experiments, the conditions used for preparingsucrose-6-acetate with dibutyltin oxide and acetic anhydride were optimized asfollows: the mole ratio of dibutyltin oxide and acetic anhydride to sucrose were1.05and1.10separately; esterification reaction could be run at92oC for3.5hours. Underthese conditions, the yield of sucrose-6-acetate was89.0%Selective chlorination of the sucrose-6-monoesters was also a key step in thesynthesis of sucralose. In this experiment, firstly vilsmeier reagent was produced bythe reaction of SOCl2and DMF, which can be used as chlorination reagent. Theinfluence of different factors were explored. Results shows that the better reactionconditions were: the molar ratio n(SOCl2): n(sucrose-6-acetate)=7:1, the ratioDMF(mL):sucrose-6-acetate(g)=8:1, the reaction temperature112oC, and the reactiontime2hours. Under these conditions, the yield of sucralose-6-acetate was60.2%.In the solution of sodium methoxide/methanol, sucralose-6-acetate can beconverted to sucralose at5°C and pH=10-12. The crude product of sucralose wasrecrystallized twice from water to give pure sucralose. Through these three steps, thetotal yield of sucralose was42.5%.