咖啡因制备方法研究进展

Technical Development on Preparation of Caffeine

综述了咖啡制备的诸种方法(包括人工合成法、溶剂萃取法、升华法和超临界流体萃取法)。人工合成咖啡因一般以氰乙酸为原料,经过缩合、环化、还原等步骤合成。溶剂萃取法一般以热水、乙醇和氯仿为萃取剂。分为浸取、除杂、脱色、重结晶等步骤。升华流程一般有以下两种:升华提取→去杂→重结晶→一水咖啡因和浸提→去杂→升华→无水咖啡因。代表高新技术的超临界流体(二氧化碳)萃取法,经历了由理论的提出到工业的应用,由间歇法到半连续法生产的发展历程,详细介绍了代表了各个发展历程的代表工艺实例。

Technology of caffeine process (including artificial synthesis, extraction by solvent, sublimation and supercritical fluid extraction) is summarized. Artificial caffeine is synthesized by cyanoacetic acid through condensation, cycliza-tion,deoxidization,etc. Also caffeine could be extracted by hot water,ethanol,chloroform by the following steps such as sublimation→de→impurity→re - crystallization→hydrate caffeine and immersing→de - impurity→sublimation→caffeine. The supercritical fluid (carbon dioxide)extraction,which is the high and new technique,developed from the theory to its application in industry,from batch operation to semi - consecutive operation,is elaborated and some typical process examples are cited and evaluated as well.