Studies on the oxidation of 2,6-di-tert-butylphenol by molecular oxygen catalyzed by cobalt(II) tetraarylporphyrins bound to cationic latex

Abstract

A cationic latex has been prepared by emulsion copolymerization of styrene and divinylbenzene with 2 mol.% of quaternary ammonium ion surfactant monomer. The catalytic activity of cobalt(II) sulfonated tetraarylporphrins 1-5 supported on the cationic latex 6 was investigated in the autoxidation of 2,6-di-tert-butylphenol in water. All colloidal catalysts showed good catalytic activity in the autoxidation of 2,6-di-tert-butylphenol. Reaction products were identified as 2,6-ditert-butyl-1,4-benzoquinone and the oxidative coupling product as 3,3ʼ,5,5ʼ-tetra-tert-butyl-4,4ʼ-diphenoquinone. The rate of autoxidation reaction catalyzed by 5 supported on cationic latex was found to increase with increasing pH in the range 7.0-10.0. At constant concentration of cobalt(II) porphyrin 5 in the reaction mixture, the rate as a function of the weight of the latex showed a maximum. The rate of autoxidation increased with increasing partial pressure of dioxygen in the range between 0.2 and 1.0 atm. 5,10,15,20-tetrakis(2,4,6-trimethyl-3,5-disulfonatopheny)porphyrinatocobalt(II) bound to the cationic latex was found to be the most reactive catalyst and the latex supported 5,10,15,20-tetrakis(2,6-dichloro-3-sulfonatophenyl)porphyrinatocobalt(II) showed the highest stability.

Investigation of 3d-transition metal acetates in the oxidation of substituted dioxolene and phenols

“…H 2 O 2 or t BuOOH as oxidant to give two different oxidation products 3,3 -5,5 -tetra-tertbutyldiphenoquinone (DPQ) and 2,6-di-tert-butylbenzoquinone (BQ) [190,191]. Among the 3d-transition metals, there are more examples of copper [185,186,190,192] and cobalt salts and complexes [188,[193][194][195][196][197][198][199][200][201][202] as catalysts but use of iron and manganese are relatively less [76,187,203]. Organic ligands have also been found to be effective catalyst to form DPQ as major product [204].…”

Catalytic Properties of Cobalt meso-Tetrakis(4-methylpyridiniumyl)­porphyrin Tetratosylate in the Oxidation of Sodium Diethyldithiocarbamate

“…Дальнейшее увеличение концентрации катализатора может приводить к образованию ассоциированных форм порфирина в растворе и снижению эффективности катализа. [8] Полученные в данной работе эффективные константы скорости реакции окисления диэтилдитиокарбамата сопоставимы с величинами, полученными для данной реакции в присутствии катализатора -сульфозамещенного фталоцианина кобальта (k эф = 2,3·10 -4 -3·10 -3 с -1 ). [3,12] …”

“…[2][3][4][5][6][7] Следует отметить, что в качестве катализаторов окисления соединений RSH исследованы, главным образом, координационные соединения фталоцианинов. Исследованию порфиринов и их координационных соединений в аналогичном процессе окисления меркаптоэтанола посвящена работа [8] . Поэтому расширение круга порфириновых катализаторов и субстратов представляет определенный научный интерес.…”

Manganese porphines-NH2@SBA-15 as heterogeneous catalytic systems with homogeneous behavior: Effect of length of linker in immobilized manganese porphine catalysts in oxidation of olefins

“…Even though the homogeneous catalytic systems are often more effective than the heterogeneous analogues, the difficulties in separation of the catalyst is the disadvantage of them and therefore the researchers are interested to design and construct more effective heterogeneous catalytic systems. Synthetic metalloporphines as model catalysts for cytochrome P450 have been extensively studied for oxidation of variety compounds using various oxidizing agents [2][3][4][5][6][7][8].…”