Science and Technology Production
Article
Authorship
SAD, MARIA EUGENIA
;
Cristina Liliana Padró
;
Carlos Rodolfo Apesteguía
Date
2007
Publishing House and Editing Place
Elsevier
Magazine
APPLIED CATALYSIS A-GENERAL,
vol. 342
(pp. 40-48)
Elsevier
Summary
Information provided by the agent in
SIGEVA
The selective synthesis of p-cresol by gas-phase alkylation of phenol with methanol was studied on SiO2-Al2O3 and zeolites HBeta, HZSM5 and MCM22. Cresols were formed from phenol alkylation of methanol via two parallel pathways: the direct C-alkylation of phenol and the consecutive transformation of anisole intermediate obtained by O-alkylation of phenol. Methylation of o- and p-cresol led to the formation of 2,6- and 2,4-xylenols while anisole produced methylanisoles either by alkylation with ...
The selective synthesis of p-cresol by gas-phase alkylation of phenol with methanol was studied on SiO2-Al2O3 and zeolites HBeta, HZSM5 and MCM22. Cresols were formed from phenol alkylation of methanol via two parallel pathways: the direct C-alkylation of phenol and the consecutive transformation of anisole intermediate obtained by O-alkylation of phenol. Methylation of o- and p-cresol led to the formation of 2,6- and 2,4-xylenols while anisole produced methylanisoles either by alkylation with methanol or by disproportionation. Regarding the cresol isomers distribution, p- and o-cresol were the major products on all the samples while m-cresol formation remained always lower than 6%. SiO2-Al2O3, HBEA and HZSM5 exhibited similar initial p-cresol:o-cresol ratios, between 0.6-0.8 In contrast, p-cresol was the predominant product on HMCM22 because the sinusoidal 10-member ring channels of this zeolite were particularly suitable for improving by shape selectivity the formation of p-cresol. Thus, we report here for the first time that p-cresol yields of 55% and p-cresol:o-cresol selectivity ratios of 4 are obtained on MCM22 by gas-phase alkylation of phenol with methanol at 473 K and contact time of 350 g h/mol.
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