Study On The Synthesis Technology Of Amino Acid Esters Using Solid Acids

Amino acids esters, of which the synthesis has rapidly become a new research field in recent years, have been extensively used as medical semi-product, food additives, cosmetic additives, mineral flotation assitives, germicides, etc. So resesrch on the synthesis of amino acids esters is of great significance both in theoretical and in practical side.Solid acid catalyst has a lot of advantages, such as high activity, good selectivity, no corrosion to equipments and preventing acid wastewater from draining off, etc. It is considered as the first choice catalysts of amino acid easterification in the future. Ion exchange resin which is a kind of solid acid catalyst, has been widely applied to organic synthesis. Microwave irridation is introduced instead of traditional heating in the synthesis can save energy, save water, greatly shorten reaction cycle, so the production cost can be decreased radically.Preparation technologies of a series of amino acids esters have been studied systematically, and it contains several aspects:Free phenylalanine isoamyl ester has been synthesized from L-phenylala-nine and isoamyl alcohol by direct esterification with resin as catalyst which is the most effective of six familiar strong acidic cation exchange resins. The influentical factors have been studied and optimized. After three successive experiments, activity and capacity of the catalyst remains on the initial level indicating good stability. And the mechanism of esterifition of amino acid using strong acid resin as catalyst has been primarily dicussed.A series of free Amino acid isopropyl ester, Amino acid isobutyl ester and Amino acid isoamyl ester have been synthesized by direct esterification with D061 resins as catalyst which is the most effective of six familiar strong acidic cation exchange resins. Final products have been characterized by IR,1HNMR. The effect of dehydrating reagents on reaction time and the yield of esterification has been investigated. The differences of reflux temperature and the yield of esteri-fication on the synthesis of various amino acid ester have been analyzed.Microwave irridation has been introduced instead of traditional heating in the synthesis of a series of free Amino acid isopropyl ester and Amino acid isobutyl ester. The effects of microwave irradiation power and reaction time on esterification reaction have been discussed. The synthesis processe of amino acid ester has been optimized. Theses two technologies have been analyzed summarized.