Glycerol Phosphatidylcholine (L-α-GPC) Prepared By The Reaction Of L-α- Inorganic Base-catalyzed Transesterification Of Natural Phospholipids

L-α-Glycerophosphocholine (GPC for short), a water-soluble metabolites, is naturally exist in the body of human and animals. It has remarkable ability in physiological function, such as supplying choline, increasing the level of neurotransmitters and promoting the secretion of growth hormone, etc. Therefore, it is widely used in health care industry and pharmaceutical industry.In this paper, The craft process on making GPC by use of transesterification reaction which use natural phospholipids (phosphatidyl choline, PC for short) as raw materials, sodium alcoholate and supported sodium silicate as inorganic base catalysis was studied. It is investigated the effects which influenced by types of catalyst, conditions of preparation and reaction contions. The regularity of the transesterification reaction was concluded in order to accumulate basic data for scale-up progress and practical application.For the transesterification catalyzed by sodium alkoxide, two homogeneous reaction systems of sodium methoxide/methoxide and sodium ethoxide/ethoxide were researched respectively. The effects of catalyst dosage, reaction temperature, the concentration of PC were investigated.The optimal reaction condition of the sodium methoxide/methoxide system is as follows:the dosage of catalyst is0.4g/L, the reaction temperature is30℃, at10.5mmol/L PC concentration for90min, PC conversion and GPC yield were97.0%,92.6%respectively. The optimized condition of sodium ethoxide/ethoxide is as follows:the dosage of catalyst is0.6g/L, the reaction temperature is40℃, at10.5mmol/L PC concentration react for90min, PC conversion and GPC yield were98.1%,94.9%, respectively.In order to solve the catalyst reclamation and product separation problems, attempted to use supporting solid base catalyst to catalyze PC heterogeneous transesterification to prepare GPC. Used sol gel method to prepare solid base catalyst Na/SiO2, optimized the preparation conditions of catalyst, and studied the process conditions of heterogeneous reaction. The research show that the suitable preparation conditions were:Na/Si ratio was60/40, calcination temperature was600℃, calcination time was6h. Under the optimized conditions of catalyst amount of9%, reaction temperature of65℃, stirring speed of350rpm, PC concentration of10.5mmol/L, after280min, the conversion of PC and the yield of GPC were98.4%and96.1%respectively. The catalyst samples were characterized by techniques such as TG/DTG, FT-IR, XRD, Hammett indicator method and so on, The result show that higher Na/Si ratio and suitable calcination temperature were conducive to the crystal structure of Na2SiO3and Na2Si2O5and the catalytic activity.Kinetics of PC transesterification by three kinds of catalytic was analyzed, respectively. The experimental data regression showed that both homogeneous and heterogeneous reaction complied with the pseudo-first order kinetic model. According to Arrhenius Equation, the activation energy of sodium methoxide, sodium ethoxide and solid base catalyst Na/SiO2were48.42kJ/mol,40.3kJ/mol and71.6kJ/mol, respectively.