Xylenols transalkylation

The Brpnsted acidity in the zeolite is responsible for the transalkylation of the methyl to the phenolic ring, giving phenol, cresols, and xylenols as products and so reduces the loss of carbon as methane. The metal function catalyzes demethylation, hydrodeoxygenation, and hydrogenation. Pt/SiO, a catalyst with only a metal function, produced only traces of methylated products, with 70% benzene, 15% methane, and 13% cyclohexane at complete anisol conversion, while the bifunctional Pt/beta yielded 50% benzene, 25% toluene, 10% xylene, 5% methane, and almost no saturated products. Use of a bifunctional catalyst is thereby very beneficial. Moreover, the presence of the metal also improves the catalyst stability with a moderate reduction in coke formation. 

---