Pyrolysis of cellulose in Fe‐[Bmim]OTf catalyst for selective production of 4,4‐dimethyl‐2‐cyclohexen‐1‐one

Abstract

Abstract4,4‐dimethyl‐2‐cyclohexene‐1‐one is a valuable ketone compound, which is an important (±)‐cuparene and filicinic acid intermediate, but the synthetic method of 4,4‐dimethyl‐2‐cyclohexene‐1‐one is rarely mentioned in the marketplace. This article, a new method is proposed for the preparation of 4,4‐dimethyl‐2‐cyclohexen‐1‐one in high yield by selective catalytic pyrolysis of cellulose with FeCl3‐doped [Bmim]OTf magnetic ionic liquids. By studying the effect of temperature on the yield of pyrolysis products in [Bmim]OTf, the results showed that the optimal pyrolysis temperature of cellulose in [Bmim]OTf was 330°C and the maximum relative content of 4,4‐dimethyl‐2‐cyclohexen‐1‐one was 86.81%. In addition, different FeCl3/[Bmim]OTf mass ratios were found at 330°C. The relative yield of the target product reached a maximum (91.31%) when iron ions with excellent catalytic activity were introduced, at which the FeCl3/[Bmim]OTf mass ratio was 10%. At last, based on the basic model of cellulose monomer, the evolution pathway of ketones products was proposed, which provides ideas for the production of sustainable chemical products from cellulose.