Selective oxidation of ethylbenzene with air catalyzed by simple μ-oxo dimeric metalloporphyrins under mild conditions in the absence of additives

The paper reported the catalysis of simple mu-oxo dimeric metalloporphyrins for the selective oxidation of ethylbenzene with air under mild conditions in the absence of additives. Two simple mu-oxo dimeric metalloporphyrins, mu-oxo-bis(tetraphenyl-porphinato)iron [TPPFe](2)O and mu-oxo-bis(tetraphenylporphinato)manganese [TPPMn](2)O were used as catalyst in the oxidation of ethylbenzene with air under mild condition. The results show that the products of ethylbenzene oxidation catalyzed by [TPPFe](2)O or [TPPMn](2)O with air are acetophenone and (x-phenylethanol exclusively under T > 60 degreesC and atmospheric pressure and in absence of any additive. [TPPMn](2)O is an active catalyst with high selectivity and turnover number of 2134 for oxidation of ethylbenzene by air when temperature reacts at 70 degreesC. The kinetic study shows that the ethylbenzene oxidation is zero-order for oxygen and first-order for ethylbenzene. The activation energy of the reaction is 72.7 kJ/mol. Comparing with the corresponding monometalloporphyrins TPPFeCl and TPPMnCl, [TPPFe](2)O and [TPPMn](2)O have the better catalytic activity for ethylbenzene oxidation with air without any additive under mild conditions. (C) 2002 Elsevier Science B.V. All rights reserved.