Zhang Qiaohong, He Honghao, Wang Huibin, Zhang Zhan, Chen Chen
School of Material Science and Chemical Engineering, Ningbo University 818 Fenghua Road Ningbo 315211 PR China
China Tobacco Henan Industrial Co. Ltd No.8 The 3rd Avenue Zhengzhou 450001 PR China
RSC Adv. 2019 Nov 26;9(66):38891-38896. doi: 10.1039/c9ra08185b. eCollection 2019 Nov 25.
A series of -alkyl pyridinium salts were synthesized and employed as metal-free catalyst for the selective oxidation of methyl aromatic hydrocarbon with molecular oxygen. The electronic effect of the substitutes was found to be an important factor for the catalytic performance. With the introduction of electron-donating substitute -N(CH), the conversion of -xylene and selectivity of -toluic acid could be simultaneously increased. 1-Benzyl-4-,-dimethylaminopyridinium salt showed the highest catalytic activity, and 95% conversion with 84% of selectivity to -toluic acid could be obtained for the selective oxidation of -xylene. Several methyl aromatic hydrocarbons could all be efficiently oxidized with the reported catalyst at the absence of any metal species.
合成了一系列的 - 烷基吡啶鎓盐，并将其用作无金属催化剂，用于分子氧选择性氧化甲基芳烃。发现取代基的电子效应是催化性能的一个重要因素。随着给电子取代基 -N(CH) 的引入，对二甲苯的转化率和对甲苯甲酸的选择性可以同时提高。1-苄基-4,-二甲基氨基吡啶鎓盐表现出最高的催化活性，对对二甲苯进行选择性氧化时，可获得95%的转化率和84%的对甲苯甲酸选择性。在没有任何金属物种的情况下，几种甲基芳烃都可以用所报道的催化剂有效地氧化。
