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.Amino acids have two properties, and are difficult to dissolve in the organic solvents, which made them difficult to choose the right conditions for esterification and to improve the selectivity and to separate and purify the products. It can reduce the cost of preparation amino acid esters if the methods of preparation can be improved especially using the comparatively inexpensive catalyzers.Preparation technologies of a series of amino acids esters were studied systematically, and it contains several aspects:1. The method of TLC, which is used to inspect amino acids and their esters, was improved. It made the method reduce operations and save the instruments and reagents.2. Esterification of amino acids using p-toluenesulfonic acid by common heating methods affords seven p-toluenesulfonic acid salt of amino acids esters. The influentical factors were studied and optimized. Final products were characterized by melting point determination, IR, 1H-NMR, 13C-NMR.3. Microwave irridation was introduces in the p-toluenesulfonic acid salt of amino acids esters. Theses two technologies were analyzed summarized.4. Preparing free amino acid esters were studied esterified by strong acid resin, it offords eight free amino acid methyl and ethyl esters. The influentical factors were studied and optimized. Final products were characterized by IR, 1H-NMR.And the mechanism of esterifition of amino acid using strong acid resin as catalyst was primarily dicussed.