Selective alkylation of phenol to 2,6-xylenol over vanadia—chromia mixed oxide catalysts

doi:10.1016/S0166-9834(00)81430-X

Applied Catalysis

Volume 49, Issue 1, 3 April 1989, Pages 165-174

https://doi.org/10.1016/S0166-9834(00)81430-X Get rights and content

Abstract

Vapour-phase alkylation of phenol with methanol was carried out over a series of simple and mixed oxides of vanadia and chromia of different atomic ratios in a fixed-bed, continuous-flow reactor at 573–723 K and 1–20 bar pressure. Preferential orthoalkylation with 90% selectivity took place with the formation of o-cresol and 2,6-xylenol. The acidity of the catalysts was measured by n-butylamine titration and by cyclohexanol dehydration at 523 K, which was also used as an acidity index. Variation of the activity with the atomic ratios of V and Cr in the mixture was correlated with acidity, total phenol conversion and selectivity for o-cresol and 2,6-xylenol. An increase in acidity increases the selectivity for 2,6-xylenol. Pure vanadia is a better alkylation catalyst than pure chromia. However, addition of a small amount of chromia to vanadia improves the acidity and also the total activity and selectivity for 2,6-xylenol.

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: RRL(H) Communication NO. 2247.

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Selective alkylation of phenol to 2,6-xylenol over vanadia—chromia mixed oxide catalysts

Abstract

Appl. Catal.

Appl. Catal.

Appl. Catal.

Mater. Chem. Phys.