Hydrochloric Acid → Ethyl 5-oxo-L-prolinate

Participants

Reaction Steps

A mixture of ethanol and glutamic acid was initially charged in a stirred vessel (A). The fraction of glutamic acid was 0.1% of the ethanol fraction. The mixture was conveyed continuously through the reactor (C) at a pressure of 72 bar by a suitable pump (B). The tubular reactor (C) was heated to a temperature of 260° C. by the heater (D). A carrier stream of pure ethanol from the reservoir (F) was heated to the same temperature using the preheater (G). At the mixing point (H), the carrier stream was mixed with the reactant stream (ratio 50/50) and fed to the reactor (C). The preheating temperature selected was so high that there was already reaction temperature at the mixing point, so that the temperature gradient in the reactor (C) was sufficiently small to prevent carbonization at the wall. The residence time in the tubular reactor (C) was 40 sec. With the aid of the control valve (E), the pressure was kept at the target value mentioned. At the outlet of the system, the reacted solution was introduced into 1 molar HCl. According to HPLC, 50% product yield (ethyl pyroglutamate) was obtained.

Provenance & Evidence