The effect of different Si/Al ratios and reaction conditions on the phenol methylation activity of MCM-22
MCM-22 samples of different Si/Al ratios were prepared using various silica sources and agitation conditions and were characterised using BET, SEM, XRD and elemental analysis. Two samples with Si/Al ratios of ~10 and ~100 were used in a study of the alkylation of phenol with methanol in a flow reactor. Phenol conversions did not vary much with Si/Al ratio in the gas phase but were greater at high Si/Al ratios in the liquid phase. For the Si/Al = 10 sample, selectivities to anisole and cresols were hardly influenced by the reaction phase but varied considerably at Si/Al = 100. p-Cresol selectivity increased significantly in liquid phase reactions but was not greatly influenced by changes in the Si/Al ratio. A series – parallel mechanism is proposed to explain these results. The primary products are anisole, formed via a rapid alkylation of the side chain, and o-cresol, formed via a slower alkylation of the aromatic ring. Secondary reactions, which may occur, involve a slow monomolecular transalkylation to convert anisole to o-cresol or a reaction between anisole and phenol to form cresol and phenol.
C. T. OConnor S. Sauerbeck G. Moon W. Bohringer J. C. Q. Fletcher
Centre for Catalysis Research, Department of Chemical Engineering, University of Cape Town, Rondebosch, 7701, South Africa
国际会议
北京
英文
2007-08-12（万方平台首次上网日期，不代表论文的发表时间）