Ethylation and disproportionation of ethylbenzene over substituted AFI type molecular sieves

The vapour and liquid phase ethylation of ethylbenzene was performed over AlPO4-5 and its substituted counter parts. The results obtained for vapour phase reactions have shown a higher catalytic activity at 350 and 400 °C. The catalysts, however, exhibited a faster deactivation rate. The results obtained for liquid phase reaction have shown a higher selectivity for para-diethylbenzene (84.4%) than the vapour phase reaction (41.5%). MnAPO-5 was found to be active up to 240 h for the liquid phase reaction. para-Diethylbenzene, meta-diethylbenzene and polyalkylbenzene were the major products obtained for ethylation of ethylbenzene. When ethylbenzene passed over MnAPO-5 yielded products, such as benzaldehyde, acetophenone, styrene and 2,3-diphenylbutane. This showed a preference for oxidation rather than disproportionation followed by alkylation. Notwithstanding the better acid characteristics of ZSM-5, MnAPO-5 could be a better choice for this class of reaction essentially due to its higher para selectivity.

Graphical abstractThe vapour and liquid phase ethylation of ethylbenzene performed over AFI type molecular sieves. The results of vapour phase reactions show a faster deactivation of the catalyst due to temperatures at which the reactions performed. The liquid phase reactions showed a higher selectivity for para-diethylbenzene (84.4%) than the vapour phase reaction. When ethylbenzene passed over MnAPO-5, yielded styrene and 2,3-diphenylbutane. This showed a preference for oxidation rather than disproportionation followed by alkylation.Figure optionsDownload full-size imageDownload as PowerPoint slide