Experimental and DFT study of the partial oxidation of benzene by N2O over H-ZSM-5: acid catalyzed mechanism.
The reaction mechanism for hydroxylation of benzene by N(2)O has been studied on chemically modified ZSM-5 catalysts. A maximum in catalytic activity and selectivity was reached for steamed samples under mild conditions (about 30% conversion with 94% selectivity). Chemical modifications, through ion exchange (H(+) versus Na(+)), have demonstrated the importance of the presence of Brönsted acid sites. The results obtained suggest a Langmuir-Hinshelwood mechanism between benzene and N(2)O adsorbed on two distinct active sites. A density functional theory study considering the possible reaction intermediates also confirmed the possible formation of protonated nitrous oxide, leading to a Wheland-type intermediate, thus supporting an electrophilic aromatic substitution assisted by the confined environment provided by the active zeolite framework.
Esteves
Pierre M
PM
Instituto de Química, Universidade Federal do Rio de Janeiro (UFRJ), Cidade Universitaria-Ilha do Fundão, Centro de Tecnologia-Bloco A, Rio de Janeiro-RJ, 21949-900, Brazil.
Louis
Benoît
B