Regioselective Synthesis, Characterization And Physicochemical Properties Of Sucrose Esters

Sucrose esters(SE) have attracted continual interest in the past decades owing to their superior performance and compatibility in the health and environmental arenas and are currently being employed in the food,cosmetic and detergent industries.In addition,several types of synthetic SE have shown potent insecticidal activities and could be a new kind of insecticide with a brilliant commercial prospect.Research and development of it will be particularly important for China which is a big agricultural country.SE compounds were prepared in this work by esterification and transesterification of sucrose using DMF as reaction solvent.The influences of reaction conditions on the conversion of acylating agent and degree of substitution were investigated.Molar ratio of acylating agent to sucrose was found to be the critical factor to the degree of substitution.The reaction activities of free hydroxyl groups in sucrose follows the order OH-6＞OH-6'＞OH-1'＞secondary-OHs.Regioselective formation of 6-O-acylsucroses and 6,3'-di-O-acylsucroses in one pot with good yields were achieved by a typical acylation method of sucrose via dibutylstannylene acetal.Explanations for the regioselectivities observed during this stannylene acetal mediated reaction were also proposed based on the structures of stannylene acetal in solution and the intramolecular migration of stannylenes.C₈SE provides high levels of mortality against broad range of arthropods and will have a bright commercial future.6-O-acylsucroses and 6,3'-di-O-acylsucroses were fully characterized using FT-IR, ESI-MS and NMR spectroscopy.Spectral assignments of ¹H and ¹³C NMR spectra were performed using ¹H-¹H COSY,¹H-¹³C COSY and HMBC techniques.It was found that HMBC experiment was a convenient method to determine the position of acylation.A high performance liquid chromatographic method has been developed for the separation and quantitation of sucrose ester analogs using an evaporative light scattering detector(ELSD) in combination with the electrospray ionization mass spectrum(ESI-MS) technology.By varying the mobile phases and gradient conditions,the complex mixtures of synthetic or commercial sucrose esters were completely separated into several fractions such as mono-,dior higher esters with different regioisomers in each one on a single run.A separation and quantitative method of ten pure monoesters and diesters was also described to evaluate the method's potential application in the quantitiation of all sucrose ester analogs using external standards.The described method is found to be accurate,relatively inexpensive, straight-forward and reproducible and in principle can be readily applied to the analysis of any sucrose ester analogs of interest with little variation to meet all requirements of qualitative and quantitative analytical procedure.In order to get some precise structure-activity relationships in this series of compounds, surface properties and interfacial properties of pure SE compounds and sucrose esters mixtures with different hydrophobic chain lengths were investigated.A two-dimensional model of solubility parameters was developed to interpret the interfacial phenomena of these compounds.Some physiochemical properties of these compounds,such as HLB value, emulsifying power,stability in hard water,foamability and form stability were also investigated.