食用香料呋喃酮制备过程中中间体脱羧反应机理研究  

Research on Mechanism of Decarboxylation of Intermediates Involved in Preparation of Flavor Furanone

作　　者：王禹茼 丁瑞[1] 刘永国[1] 梁森[1] 孙宝国[1] 田红玉[1] WANG Yutong;DING Rui;LIU Yongguo;LIANG Sen;SUN Baoguo;TIAN Hongyu(School of Light Industry,Beijing Technology and Business University,Beijing 100048,China)

机构地区：[1]北京工商大学轻工科学技术学院,北京100048

出　　处：《食品科学技术学报》2023年第4期118-125,共8页Journal of Food Science and Technology

基　　金：国家自然科学基金重点项目(32130083)。

摘　　要：对α-甲基二甘酸二乙酯与草酸二乙酯反应制备呋喃酮的工艺路线中中间体的脱羧作用进行了探讨。在该工艺路线中,原料通过2次的Claisen酯缩合、酯基水解、甲基化、脱羧等反应生成呋喃酮。在反应过程中原料α-甲基二甘酸二乙酯的2个酯基均被脱除,但脱除的方式明显不同。第1个酯基是在Claisen酯缩合完成后,在甲醇钠的作用下,通过先加成后消除的机理,以碳酸酯的形式脱除;第2个酯基是在甲基化反应完成后,在碱性条件下通过羧酸钠盐的中间体发生脱羧反应,以二氧化碳的形式被脱除的。为验证中间体脱羧机制的普遍性:β-羰基酯未经水解在碱性条件下即发生脱羧现象。通过α-乙基乙酰乙酸乙酯的烷基化反应,观察其产物(α-乙基-α-丁基乙酰乙酸乙酯)是否会发生脱羧反应,结果没有观察到α-乙基-α-丁基乙酰乙酸乙酯的预计脱羧产物(3-乙基-2-庚酮)。因此,研究表明普通β-羰基酯并不会通过酯基的先加成后消除反应发生脱羧作用。而食用香料呋喃酮制备过程中的2个较为反常的脱羧作用的驱动力均与脱羧后形成具有芳香性的稳定的共轭结构有关。研究阐明了食用香料呋喃酮制备过程的反应机理,希望研究结果对于该工艺路线的改进优化具有参考价值。The decarboxylations of the intermediates involved in the industrial production of furanone starting from diethylα-methyldiglycolate and diethyl oxalate were investigated.Furanone was obtained through two successive Claisen condensations,hydrolysis of esters,methylation,and decarboxylation in this process route.During the reaction,both two ester groups of diethylα-methyldiglycolate were removed during the process,but the approaches of two decarboxylations were obviously different.After the Claisen ester condensation,the first ester group was removed in the form of a carbonate by an addition-elimination mechanism in the presence of CH 3 ONa.The second ester group was removed in the form of CO 2 through a sodium carboxylate intermediate under basic conditions following the methylation.In order to verify the generality of decarboxylation of the intermediate,the decarboxylation ofβ-carbonyl ester occurred without hydrolysis under basic conditions.The alkylation ofα-ethyl acetoacetate was carried out to observe whether the product(α-ethyl-α-butyl acetoacetate)would undergo decarboxylation.However,the expected decarboxylation product ofα-ethyl-α-butyl acetoacetate(3-ethyl-2-heptanone)was not observed.Therefore,the results indicated that commonβ-carbonyl esters could not undergo decarboxylation attacked by a base through an addition-elimination mechanism.The driving force for the two abnormal decarboxylation in the preparation of flavor furanone was due to the formation of stable aromatic conjugated structures after decarboxylation.This research had clarified the reaction mechanism of the preparation process of the flavor furanone,which would be helpful for the improvement and optimization of the technical route.

关 键 词：香料 呋喃酮 α-甲基二甘酸二乙酯 草酸二乙酯 β-羰基酯 脱羧 

分 类 号：TS202.3[轻工技术与工程—食品科学]