Abstract

Different ways of preparing 2,3,5-trimethyl-1,4-benzoquinone (TMQ), a key intermediate in the synthesis of vitamin E, via the catalytic oxidation of 2,3,6-trimethylphenol (TMP) are considered. It is shown that aqueous solutions of Mo–V phosphoric heteropolyacids (HPAs) are promising catalysts for the oxidation of TMP with oxygen. Different technological options are analyzed for using HPAs in this reaction: the one-stage homogeneous acetic acid oxidation of TMP and a biphasic two-step procedure. The efficiency of a biphasic version that ensures high (up to 99.5%) selectivity for TMQ and high catalyst productivity in the target reaction (≈600–800 g TMQ \({\text{L}}_{{{\text{cat}}}}^{{ - 1}}\) h⁻¹) is proved.

中文翻译：

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基于杂多酸溶液的氧化还原过程的均相催化剂III：开发制备2,3,5-三甲基-1,4-苯醌的有效方法

摘要

考虑了通过2,3,6-三甲基苯酚（TMP）的催化氧化制备维生素E合成中的关键中间体2,3,5-三甲基-1,4-苯醌（TMQ）的不同方法。研究表明，Mo-V磷酸杂多酸（HPA）的水溶液是用氧气氧化TMP的有前途的催化剂。分析了在此反应中使用HPA的不同技术选择：TMP的一步均相乙酸氧化和两步两步程序。双相形式的效率可确保对TMQ的高选择性（高达99.5％）和目标反应中的高催化剂产率（≈600–800 g TMQ  \（{\ text {L}} _ {{\ text {cat证明}}}} ^ {{{-1}} \） h ^-1）。