Atom economical benzylation of phenol with benzyl alcohol using 20 % (w/w)Cs2.5H0.5PW12O40 supported on mesocellular foam silica (MCF) and its kinetics

摘要

Traditionally benzylation of phenol is carried out with benzyl chloride which is corrosive and difficult to handle, and the resultant reaction is not atom economical. Benzyl alcohol is an alternative to benzyl chloride which is safe and easy to handle. Benzyl phenols are industrially important products particularly in plastic, rubber and petroleum industries. In present study, cesium salt of dodecatungstophosphoric acid (Cs2.5H0.5PW12O40, Cs-DTP) supported on mesocellular foam (MCF) silica was used as catalyst among others. The activity of prepared catalyst, 20% (w/w) Cs-DTP/MCF was compared with Amberlyst-15, montmorillonite clay K10, S-ZrO2 and unsupported Cs-DTP catalyst. The supported catalyst showed better performance because of even distribution of acidic sites on MCF. The effect of reaction parameters were studied in detail and it was found that reaction follows second order kinetics. The activation energy was found to be 15.94 kcal/mol. The catalyst was found reusable.