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以交联聚苯乙烯(CPS)微球为基质,经过几步大分子反应在微球表面合成与固载了N-羟基邻苯二甲酰亚胺(NHPI),形成固载有NHPI的聚合物微球CPS-NHPI。本文主要将CPS-NHPI与过渡金属盐组成共催化体系,用于分子氧氧化甲苯的反应,考察了该非均相催化剂的催化特性与催化氧化机理。结果表明,几种过渡金属盐中,Co(OAc)2的助催化效果最好;微球CPS-NHPI与Co(OAc)2所构成的共催化体系,在温和条件(80℃和常压氧气)下可有效地将甲苯深度氧化为苯甲酸,显现出高的催化活性(甲苯转化率达到57%)与优良的选择性(苯甲酸的选择性达到84%)。催化氧化反应遵循自由基链式反应机理。主催化剂CPS-NHPI固载的NHPI与助催化剂Co(OAc)2适宜的摩尔比为14∶1,主催化剂所含NHPI为底物的12(mol)%时,催化剂用量较为合适。固体催化剂CPS-NHPI具有良好的再循环使用性能。
With cross-linked polystyrene (CPS) microspheres as matrix, N-hydroxyphthalimide (NHPI) was synthesized and immobilized on the surface of microspheres through several steps of macromolecule reaction to form NHPI- Microspheres CPS-NHPI. In this paper, CPS-NHPI and transition metal salts were co-catalyst system for the molecular oxygen oxidation of toluene. The catalytic properties and catalytic oxidation mechanism of the heterogeneous catalyst were investigated. The results showed that Co (OAc) 2 had the best promoter activity among several transition metal salts. The co-catalysis system consisted of microspheres CPS-NHPI and Co (OAc) 2 under mild conditions ) Can effectively deeply oxidize toluene to benzoic acid, exhibiting high catalytic activity (toluene conversion of 57%) and excellent selectivity (benzoic acid selectivity of 84%). Catalytic oxidation follow the free radical chain reaction mechanism. The suitable molar ratio of the main catalyst CPS-NHPI immobilized NHPI to the co-catalyst Co (OAc) 2 is 14: 1, and the main catalyst contains 12 mol% of the NHPI contained in the catalyst. Solid catalyst CPS-NHPI has good recycling performance.