Abstract:

Alkyl-substituted benzoquinones were versatile building blocks for a variety of biologically active compounds. The catalytic oxidation of 2,3,6-trimethylphenol (TMP) to 2,3,5-trimethyl-1,4-benzoquinone (TMQ, vitamin E precursor) with oxygen gas was proposed under mild conditions. The cross-linked porous polymer (PPhen) was synthesized by Friedel-Crafts alkylation of 1,10-phenanthroline, and the related Cu catalysts (Cu/PPhen) were prepared. The prepared Cu/PPhen catalysts were characterized by nitrogen adsorption and desorption isotherms, scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS) .The basic structure of the Cu/PPhen catalysts were obtained. Reaction conditions, such as catalyst loading, solvent, oxygen pressure, reaction temperature and reaction time were studied, and 2,3,5-trimethyl-1,4-benzoquinone was obtained in 99% yield with the optimized reaction conditions. The optimized reaction conditions were achieved as 136 mg 2,3,6-trimethylphenol with 150 mg the Cu/PPhen-4 catalyst in 2 ml acetonitrile, under 0.5 MPa O₂ at 40℃ for 4 h. The Cu/PPhen-4 catalyst has good stability and can be recovered at least five times with almost no decrease in activity.

Key words: coper catalyst, 2,3,5-trimethyl-1,4-benzoquinone, oxidation, reaction, polymers

摘要：

烷基取代的苯醌可用作多种生物活性化合物的功能结构单元。提出了一种在温和条件下，用氧气氧化2,3,6-三甲基苯酚（TMP）得到2,3,5-三甲基-1,4-苯醌（TMQ，维生素E前体）的方法。利用Friedel-Crafts烷基化反应，成功制备了一种基于1,10-菲罗啉的交联多孔聚合物负载铜催化剂Cu/PPhen。采用氮气吸附脱附、SEM、FTIR和XPS对催化剂Cu/PPhen-4进行了一系列的表征，获得了催化剂的基本结构特征。并考察了催化剂的加入量、溶剂、氧气压力、反应温度以及反应时间等因素对Cu/PPhen-4催化氧化制备2,3,5-三甲基-1,4-苯醌的影响，得到最佳的工艺条件。当2,3,6-三甲基苯酚的加入量为136 mg时，催化剂量为150 mg，乙腈量为2 ml，0.5 MPa的氧气，40℃下反应4 h，2,3,5-三甲基-1,4-苯醌的收率可以达到99%。催化剂Cu/PPhen-4具有较好的稳定性，可以回收至少五次，活性几乎没有下降。

关键词: 铜催化剂, 2,3,5-三甲基-1,4-苯醌, 氧化, 反应, 聚合物