Catalytic way of transforming 2,3-dimethylphenol to para-quinone with the use of vanadium-containing heteropoly acids
作者:Yulia A. Rodikova、Elena G. Zhizhina、Zinaida P. Pai
DOI:10.1016/j.apcata.2017.09.022
日期:2018.1
decrease the optimal molar ratio of vanadium(V) to substrate. The highest yield of the desired quinone (97%) at total substrate conversion was obtained by using the biphasic water-benzene system at molar vanadium(V) to substrate ratio of 12. The temperature of 50 °C and an inert atmosphere were established to be the optimal reaction conditions. The aqueous HPA-10′ solution including the highest content of
2,3-二甲基-对苯醌(2,3-Me 2 BQ)是一种有价值的化学品,可作为软氧化剂和脱氢剂,也可作为合成子用于制备包括药品和生化物质在内的各种复杂产品。具有总组成H 3 + x PMo 12-x V x O 40(HPA-x)和H a P z Mo y的Mo-V-磷酸杂多酸(Mo-VP HPA)的Keggin型和改性型水溶液V X“ ø b(HPA-X”),分别具有高氧化电势和再生的简单可作为用于获得这种有效软氧化剂由2,3-二甲基苯酚(2,3-Me 2 P)生成的对苯二酚。通过多种分析技术,如31 P和51 V NMR光谱,电位法,滴定法和pH测量,对合成的具有不同钒含量的HPA催化剂进行了表征。发现主要形成2,3-Me 2通过连续优化反应条件来实现BQ而不是相应的二苯醌(DPQ)的单电子氧化,其中最重要的是有机溶剂和钒(V)与底物的摩尔比。如图所示,用HPA-x'替代HPA-x可以增