Vanadomolybdophosphate supported on active carbon, NPV6Mo6/C, catalyzed the oxidation and coupling reaction of 2,3,6-trimethylphenol by dioxygen to give trimethyl-p-benzoquinone and 4,4′-dihydroxy-2,2′,3,3′,5,5′-hexamethylbiphenyl, respectively, depending on the solvent used. Hydroquinones and benzyl alcohol were selectively dehydrogenated by the present system, giving the corresponding p-benzoquinones and benzaldehyde, respectively, in good yields.
METHOD FOR PRODUCING MULTISUBSTITUTED BIPHENYL COMPOUND AND SOLID CATALYST TO BE USED THEREIN
申请人:KYUSHU UNIVERSITY, NATIONAL UNIVERSITY CORPORATION
公开号:US20150274689A1
公开(公告)日:2015-10-01
A method for producing a multisubstituted biphenyl compound is represented by the following formula (2), including a step of coupling a substituted benzene compound represented by the following formula (1) in the presence of a solid catalyst with gold immobilized onto a support.
Oxidation of 2,6-disubstituted 4-methylphenols with dioxygen by using a CuCl2-poly(4-methyl-4′-vinyl-2,2′-bipyridine) catalyst gave the corresponding 4-hydroxybenzaldehydes in high yields. The activity of the catalyst and the selectivity of the products significantly depended on the reaction conditions and the composition of the catalyst. When the molar ratio of the bipyridine unit of the polymer ligand to Cu was unity, i.e., N/Cu = 2, the best results were obtained. Moreover, the reaction is likely to be promoted by coordination of the products to the catalyst. Similarly, 2,3,6-trimethylphenol and related compounds were converted to p-benzoquinones selectively with a CuCl2-poly(4-vinylpyridine) catalyst. These polymer-supported catalysts were readily recovered and are reusable without noticeable decrease of their activity.
A green catalytic method for selective synthesis of iodophenols via aerobic oxyiodination under organic solvent-free conditions
作者:Hongchuan Xin、Liangning Hu、Jianqiang Yu、Wenshou Sun、Zengjian An
DOI:10.1016/j.catcom.2017.01.019
日期:2017.4
A highly efficient catalytic method for aerobic oxyiodination of various phenols catalysed by copper(II) nitrate was achieved under mild conditions using I2 as an iodinating reagent, molecular oxygen as an oxidant, and water as a solvent. The catalyst shows not only high activity for phenols with either electron-donating or electron-withdrawing groups, but also a remarkable selectivity for the formation
6-Disubstituted phenols are oxidized with tris(2,4-pentanedionato)manganese(III), [Mn(acac)3], in glacial acetic acid to give the corresponding 4,4′-biphenyldiols in high yields, whereas similar reactions using manganese(III) acetate, [Mn(OAc)3], insted of [Mn(acac)3] quantitatively yield the corresponding 4,4′-diphenoquinones. Cross-coupling reactions of 2,6-di-t-butylphenol and other substituted phenols afford