The Research On The Synthesis Of Some Functional Lactic Acid Derivatives

As an important chemical material, lactic acid could be renewable from biological resource. Based on the summary of the progress in synthesis and applications of lactate esters and modified polylactic acids by copolymerization, three parts research work on synthesis are carried out. (1) A novel drug delivery carrier material polyphosphate ester-polylactic acid is directly synthesized via melt polycondensation; (2) Cholesteryl lactate and hexadecyl lactate are synthesized using KHSO₄ as catalyst; (3) The synthetic conditions of sodium stearyl lactylate (SSL) are studied roughly.(1) Starting from D,L-lactic acid (D,L-LA) and phenyl dichlorophosphate (PDP), copolymer polyphosphate ester-polylactic acid is directly synthesized via melt polycondensation and characterized with IR, ¹H NMR, ¹³P NMR, GPC and DSC. Two direct copolymerization methods (solution polymerization and melt polymerization), factors of direct melt polymerization on the effect of Mw are discussed.The results show that the direct melt polymerization is a better way for obtaining higher Mw. When the material was prepolymerized twice, the feed molar ratio of D,LLA / ethylene glycol (EG) / PDP was 20/1/1, and the melt polymerization is catalyzed by 0.5wt% ZnO under 160℃and 70Pa, 8h's copolymerization gives the copolymer with maximum Mw 27700.The molecular weight of polyphosphate ester-polylactic acid synthesized here is moderate. Thus, it provides material for preparing drug delivery microsphere in the next step, and also provides a simple method for synthesizing polyphosphate esterpolylactic acid.(2) Using KHSO4 as catalyst, and starting from D,L-LA, cholesterol and hexadecnol, cholesteryl lactate and hexadecyl lactate are synthesized respectively, and characterized with FTIR, UV, ¹H NMR, MS, and DSC. This work provides theoretic reference for the application of cholesteryl lactate and hexadecyl lactate in cosmetic, pharmacy and liquid crystal materials, et al.The effects of the treatment of the finished reaction systems and different azeotropic solvents on the reaction are studied. The results show that the finished reaction mixtures can be treated neither as the methods reported by references of lactate esters, nor by recrystallization. And only the separation via the column chromatography was suitable. It also shows that cyclohexane is the best water-taken reagent among cyclohexane, benzene and toluene.(3) Starting from D,L-LA and stearic acid, the synthetic conditions of SSL are studied roughly. The result shows that solvent-free synthesis of SSL can increase its esterifiaction value, and non-acid catalysts instead of strong caustic oil of vitriol can catalyze the reaction. In the future, it needs to further optimize the reaction conditions for providing a suitable process for producing the food additive SSL in the industry.