Influence of acidity of montmorillonite and modified montmorillonite clay minerals for the conversion of longifolene to isolongifolene

Isolongifolene and various other isolongifolene-based products are commercially important chemicals that find applications in perfumery and fragrance industry. These important commodity chemicals are generally prepared by homogeneous catalyzed reactions of longifolene in liquid phase. In the present study, role of acidity and acid distribution on montmorillonite, pillared interlayered clay and modified pillared clay catalysts have been studied for the first time in vapor phase system for the conversion of longifolene to isolongifolene. The number and strength of acid sites of montmorillonite clay mineral have been modified by steps of synthesis and by cations selection. Reaction of Al- pillared montmorillonite with Ru3+ yielded a catalyst with significantly higher distribution of weak acid sites while fortification of montmorillonite with Ce3+ and La3+ had little effect on total acidity and its distribution. In the present study, an attempt has been made to correlate the activity of the catalysts with total acidity, number and strength of the acid for the conversion of longifolene to isolongifolene. NH3 TPD determined the concentration and strength of acid sites.

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