PHOTOCHEMICAL-REACTIONS OF BIPHENYL AND ITS CHLORINATED DERIVATIVES ON THE SURFACES OF GAMMA-ALUMINA AND SILICA-ALUMINA

被引:29
|
作者
MAO, Y [1 ]
THOMAS, JK [1 ]
机构
[1] UNIV NOTRE DAME,DEPT CHEM & BIOCHEM,NOTRE DAME,IN 46556
关键词
D O I
10.1039/ft9928803079
中图分类号
O64 [物理化学(理论化学)、化学物理学];
学科分类号
070304 ; 081704 ;
摘要
Photochemical reactions of biphenyl and its chlorine-substituted derivatives on the surfaces of gamma-alumina and silica-alumina have been investigated. Diffuse reflectance spectra show that biphenyl molecules adsorbed on activated surfaces (T(a) > 350-degrees-C) form chemical products and charge-transfer complexes. The existence of the latter is also confirmed via observation of an EPR signal on photoirradiation into the CT band. Photoirradiation of the adsorbed organic molecules leads to a redox process on the surface, radical cations are formed, and dechlorination takes place. The coadsorption of persulfate and dinitrobenzene significantly influences the electron-transfer processes. The photochemical products on both activated and non-activated surfaces were separated by HPLC, and the collected fractions were studied spectroscopically. The important reaction of radical cations is hydrolysis resulting in hydroxybiphenyl, the radical BP(OH). is suggested as a key intermediate in hydrolysis.
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页码:3079 / 3086
页数:8
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