Synthesis And Characteristics Of Sucrose Fatty Acid Ester

The synthesis, analysis, properties of surficial chemistry and the middle-phase microemulsion of sucrose fatty acid esters (SE) have been studied in this dissertation. The molecular structure of SE isSucrose stearic acid ester is firstly prepared by esterification and transesterification, in which sucrose, stearic acid and methanol are used as main materials in the presence of DMF solvent. The surfactants are characterized by IR, MS and MS-HPLC analysis. After the optimization, the best reaction conditions of transesterification are showed as follows: molar ratio of sucrose to stearic acid ester is 2.5:1, reaction temperature is 150℃, amount of catalyst is 6% and reaction time is 7h. The transesterification yield can be up to 95.8% and the contents of monoester is 64.6%. Sucrose fatty acid esters (C12^C18) are prepared.Air-Liquid sueface tension of SE is measured by using drip volumn method at the tremperature of 298K. It implies that the values of cmc increase from 0.90×10^-4 mol/L to 4.00×10^-4 mol/L, andγcmc increase from 28.46mN·m^-1 to 43.49mN·m^-1. It shows perfect surface chemical properties, dissolution, solubilization and emulsification.The phase behavior for the quaternary microemulsion system of SE/alcohol/oil/water has been studied with modifiedε-βfishlike phase diagrams. Following conclusions are obtained: Increasing SE concentration, the amount of alcohol to form the middle-phase microemulsion is decreased at first and then increased, but the"alcohol length"increases at first and then decreases. The SE molecules with stronger lipophilic and the alcohols with longer hydrocarbon chains can facilitate the phase inversion of WinsorⅠ→Ⅲ→Ⅱand increase the solubilizing power of the microemulsion.