Catalytic oxidative decarboxylation of malic acid into dimethyl malonate in methanol with dioxygen
Catalytic oxidative decarboxylation of malic acid into dimethyl malonate in methanol with dioxygen
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甲醇中双氧催化苹果酸氧化脱羧生成丙二酸二甲酯
DOI：
10.1002/cssc.201200489
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发表时间：
2012
期刊：
影响因子：
8.4
通讯作者：
Xu Jie
中科院分区：
文献类型：
--
作者：
Liu Junxia;Du Zhongtian;Yang Yanliang;Lu Tianliang;Lu Fang;Xu Jie
近年来，利用生物质生产有价值的化学品引起了人们的广泛关注碳水化合物生物质可以很容易地转化为各种有机酸，如琥珀酸、苹果酸、天冬氨酸、谷氨酸和衣康酸。这些酸含有大量具有特定结构的氧原子充分利用这些现有的氧原子来生产含氧化学物质是一种有效的策略。脱羧在实验室和工业层面都是一个重要的转变。这种反应经常发生在生物系统中。例如，丙酮酸的氧化脱羧连接了糖酵解和柠檬酸循环在工业上，环戊酮目前主要是通过己二酸脱羧生产的通过脱羧将生物质及其衍生物转化为有价值的化学品对化学家来说是一种有价值的方法。丙二酸酯是丙二酸酯合成制备羧酸的重要试剂。然而，由于石油化工原料缺乏氧原子，这种酯很难从石油化工原料中获得。例如，生产丙二酸酯的氰化氢工艺是以剧毒原料氯乙酸和氰化钠为基础的因此，开发一种无害环境的工艺具有诱人的前景。苹果酸已被确定为生物质转化中12种有前途的糖源构建块之一与丙二酸类似，苹果酸含有一个羧基和一个亚甲基。苹果酸转化为丙二酸是一个很有前景的研究方向。在此，我们提出了通过选择性氧化脱羧将苹果酸转化为丙二酸二甲酯的初步结果（方案1）。我们最近报道了钒催化氧化CÀC键裂解5-羟甲基糠醛（HMF）成马来酸酐我们预计苹果酸转化为丙二酸可以通过选择性氧化去除羧基实现。然而，丙二酸本身是相当不稳定的，因为它很容易经历热脱羧；相反，丙二酸二甲酯比丙二酸稳定得多。以苹果酸为原料，经一锅氧化脱羧和酯化反应直接制备丙二酸酯是很有吸引力的。因此，具有氧化还原和酸性的催化剂是优选的。在前人报道的基础上，我们选择磷酸钼钒酸盐作为双功能催化剂。
The production of valuable chemicals from biomass has attracted much attention recently.[1] Carbohydrate biomass can be readily converted into a variety of organic acids, such as succinic, malic, aspartic, glutamic, and itaconic acid. These acids contain a large number of oxygen atoms with a specific structure.[2] Making full use of these existing oxygen atoms to produce oxygenated chemicals is an effective strategy. Decarboxylation is an important transformation at both the laboratory and industrial level. The reaction often occurs in biological systems. For example, the oxidative decarboxylation of pyruvate links the glycolysis and citric acid cycles.[3] In industry, cyclopentanone is nowadays mostly produced via decarboxylation of adipic acid.[4] Transforming biomass and its derivatives into valuable chemicals through decarboxylation would be a valuable approach for chemists. Malonic ester is an important reagent for the preparation of carboxylic acid by what is known as the malonic ester synthesis. However, it is difficult to obtain this ester from petrochemical feedstocks because they are deficient in oxygen atoms. For example, the hydrogen cyanide process for the production of malonic ester is based on the highly toxic raw materials chloroacetic acid and sodium cyanide.[5] The development of an environmentally benign process is thus an attractive prospect. Malic acid has been identified as one of twelve promising sugar-derived building blocks in biomass conversion.[2] Similar to malonic acid, malic acid contains both a carboxyl group and a methylene group. The conversion of malic acid into malonic acid is an interesting prospect. Herein, we present preliminary results on the transformation of malic acid into dimethyl malonate through selective oxidative decarboxylation (Scheme 1). We recently reported the vanadium-catalyzed oxidative CÀC bond cleavage of 5-hydroxymethylfurfural (HMF) into maleic anhydride.[6] We anticipated that conversion of malic acid into malonic acid could be achieved via selective oxidation by removing the carboxyl group. However, malonic acid itself is rather unstable as it readily undergoes thermal decarboxylation;[7] in contrast, dimethyl malonate is much more stable than malonic acid. It would be attractive to obtain malonic ester directly from malic acid via one-pot oxidative decarboxylation and esterification. Thus, a catalyst with both redox and acid property is preferred. On the basis of previous reports,[8] we selected phosphovanadomolybdates as the bifunctional catalysts.