Studies On The Synthesis Technology Of Sucrose Polyesters

This paper studies the synthesis technology of sucrose polyester by fatty acid ester and sucrose. This technology is consist of two main process: (1) the synthesis of palmitic acid ethyl ester; (2)the synthesis of sucrose polyester using ester exchange reaction.Palmitic ethyl ester is synthesized by palmitic acid and alcohol with solid superacid as catalyst. SO42-/TiO2, SO42/ZrO2, macroporous sulfoacid ion exchange resin-aluminium trichloride super-acid were prepared .The effects of many factors,such as varieties of catalyst (including the solid acid prepared, H7[P(W2O7)6] ·XH2O and H8[Si(W2O7)6] ·XH2O) , amounts of catalyst,reaction time and mole ratio of palmitic acid to ethanol on esterification process were studied. Using TiO2/SO42- as catalyst and orthogonal experiment technology, the optimum technological condition was obtained as follows, temperature 351K(78℃),reaction time 12h, n(palmitic acid): n(ethanol)=l:9, m(catalyst) : m(palmitic acid)=0.08: 1. Under this condition, the yield of palmitic ethyl ester can reach 96.19%.We also study the non-solvent ester-exchange technology of synthesis of sucrose polyester by palmitic ethyl ester and sucrose with phase-transfer catalyst. The influencing factors which affect the yield and esterification degree are studied. Using cetyltrimethylammonium bromide as catalyst and orthogonal experiment technology, the optimum technological condition was obtained as follows, temperature 398K(125 ℃),reaction time 8h, reaction pressure 2000Pa(15mmHg), n(sucrose): n(palmitic ethyl ester)=l:14, n(catalyst):n(sucrose+ palmitic ethyl ester)=0.0438:l, n(K2CO3):n(sucrose+ palmitic ethyl ester)=0.05:l, m(soap): m(sucrose+ palmitic ethyl ester)=1:20. Under this condition, the yield of sucrose polyester can reach 95.30% and the esterification degree can reach 7.43.