Iron exchanged tungstophosphoric acid supported on activated carbon derived from pinecone biomass: Evaluation of catalysts efficiency for liquid phase benzylation of anisole with benzyl alcohol

Abstract A series of iron-exchanged heteropoly tungstate (TPA-Fe) supported on activated carbon produced from pinecone biomass, have been investigated as catalysts for the benzylation reaction. Catalysts were characterized by FT-IR, XRD, Laser Raman, BET surface area, and ammonia TPD analysis. FT-IR, XRD, and Raman data revealed retention of the Keggin ion on activated carbon-supported catalysts. The catalytic activity of these catalysts was evaluated for liquid phase benzylation of anisole with benzyl alcohol. The catalytic activity was significantly dependent on the dispersion of TPA-Fe on activated carbon. The effect of TPA-Fe loading on activated carbon was studied ranging from 40 to 80 wt%. The catalyst with 70 wt% loading of TPA-Fe showed higher benzylation activity, which is related to variation in acidity of the catalysts. Thermal stability and structural properties of the catalysts were studied by treating the catalyst at different calcination temperatures. The benzyl alcohol conversion and selectivity towards benzylated products were also dependent on the anisole to benzyl alcohol molar ratio, reaction temperature, and catalyst concentration/loading. To know the effect of the benzylating agent, the reaction was carried out using benzyl chloride, benzyl alcohol, and dibenzylether. The preferential order for conversion of the benzylating agent was observed as benzyl chloride > benzyl alcohol > dibenzylether. This study indicated that biomass derived activated carbon is suitable support to disperse Keggin type heteropoly acid for the benzylation reaction.