An Integrated Production of Diesel Fuel Precursors from Carbohydrates and 2-Methylfuran over Sn-Mont Catalyst

Condensation of 5-(hydroxymethyl)furfural (HMF) with 2-methylfuran provides precursor of diesel fuel. However, HMF production is critical due to its tedious isolation and purification. Herein, we have developed an integrated process for production of diesel precursors directly from cheap HMF precursors and 2-methylfuran. This process involves, dehydration of carbohydrates to HMF followed by latter's condensation with 2-methylfuran to give 5,5'-((5-((5-methylfuran-2-yl)methyl)furan-2-yl)methylene)bis(2-methylfuran) (1). Over Sn-Mont catalyst, in solvents like water, DMSO and C(4)mimBr the product 1 was produced in negligible yields. The yield of 1 was significantly improved to 36% in formic acid medium. Sn-Mont facilitates the isomerization of glucose to fructose with its Lewis acid sites and formic acid promotes the dehydration of fructose to a mixture of HMF +5-(formyloxymethyl)furfural (FMF) which was further treated with 2-methylfuran in same pot. The product 1 was obtained with 40% and 54% yields from sucrose and fructose, respectively. Using this strategy xylose was converted into 5,5'-(furan-2-ylmethylene)bis(2-methylfuran) (2) in 25% yield.