Catalytic conversion of anisole over HY and HZSM-5 zeolites in the presence of different hydrocarbon mixtures

The conversion of pure anisole (with a methoxy functionality, typical of some bio-oil components) and its mixtures with propylene, n-decane, benzene, or tetralin, has been investigated over zeolites in continuous flow and pulse reactors. The dominant reaction of pure anisole is transalkylation, which produces phenol, cresols, xylenols, and methyl anisoles as main products. However, in the presence of an effective hydrogen donor like tetralin important differences in product distribution are observed. In addition, while with pure anisole in the feed a fast deactivation is observed, the addition of tetralin to the feed results in lower amounts of carbon deposits and much higher catalyst stability. By contrast, less dramatic effects on stability and carbon formation were observed with most of the other co-fed hydrocarbons investigated.

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► Conversion of anisole on acid zeolite produces a range of phenolic compounds via transalkylation.
► Extensive coke formation and strong adsorption of anisole and its products cause rapid deactivation.
► Deactivation is greatly reduced by adding tetralin or other molecules with high H-transfer capacity.
► Other hydrocarbons with weaker H-transfer capacity do little or nothing to prevent deactivation.