Alkylation of phenol with methanol over magnesium-aluminium calcined hydrotalcites

• Published in: Applied catalysis. A, General General, 1994-11, Vol.119 (2), p.241-252
• Main Authors: Velu, S., Swamy, C.S.
• Format: Article
• Language: English
• Subjects: Acid-base properties; Alkylation of phenol; Catalysis; Catalytic reactions; Chemistry; Exact sciences and technology; General and physical chemistry; Hydrotalcite; Mg/Al atomic ratio; Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry
• ISSN: 0926-860X; 1873-3875
• DOI: 10.1016/0926-860X(94)85194-8

Vapour phase alkylation of phenol with methanol was carried out in a fixed-bed flow reactor over thermally calcined magnesium aluminium hydrotalcites, with Mg/Al atomic ratios from 3 to 10. The main products were anisole, o-cresol, and 2,6-xylenol. The influence of phenol-to-methanol molar ratio, reaction temperature and contact time on the product yields were examined. The activity of these catalysts was compared with MgO, Al 2O 3 and physically mixed MgO-AL 2O 3. Of the catalysts studied, Mg-Al 4.0:1 calcined hydrotalcite (CHT) was the most active. These catalysts are more active than magnesia and γ-alumina. On the basis of the results obtained, a suitable reaction pathway was proposed. The participation of combined acidic and basic sites in the calcined hydrotalcites for the alkylation of phenol with methanol over magnesium-aluminium calcined hydrotalcites has been suggested. Prior to the reaction, the catalyst precursors were characterised by X-ray powder diffraction and surface area measurements.