The kinetics and mechanisms of gas phase elimination of the ethyl ester of amino acid hydrochlorides

Abstract

AbstractThe kinetics of the gas phase elimination of the ethyl ester of four α‐amino acid hydrochlorides have been examined over the temperature range of 339–451°C and pressure range of 8–108 Torr. The reactions, in a static reaction system, are homogeneous, unimolecular, and follow a first‐order rate law. The rate coefficient is expressed by the following Arrhenius equations:Glycine ethyl ester hydrochloride: Sarcosine ethyl ester hydrochloride: DL‐Alanine ethyl ester hydrochloride: L‐Phenylalanine ethyl ester hydrochloride The elimination of these amino ester hydrochlorides leads to the formation of the corresponding α‐amino acid and ethylene. However, the amino acid intermediates, except sarcosine, under the condition of reaction temperatures, undergo an extremely rapid decarboxylation process. These results apparently support previous reported mechanistic consideration where α‐amino acids decompose to the corresponding amines and CO2 gas. Copyright © 2006 John Wiley & Sons, Ltd.