A comprehensive investigation of the condensation of furanic platform molecules to C14–C15 fuel precursors over sulfonic acid functionalized silica supports

Abstract

Furfural has excellent potential for the production of versatile furanic platform molecules that can be upgraded to high carbon fuel precursors. 2-Methylfuran is one of the most important derivatives of furfural. The hydrogenation of furfural to 2-methylfuran results in the formation of by-products (n-butanal and 2-pentanone). Implementing all the primary and by-products from the hydrogenation reaction for the production of high carbon fuel precursors allows the complete utilization of the lignocellulosic xylose derived furfural. In this work, a self-condensation reaction of 2-methylfuran and its cross-condensation reactions with furfural, n-butanal and 2-pentanone have been implemented to produce C14 and C15 fuel precursors. Sulfonic acid based catalysts with and without alkyl chain linkers supported on silica nanoparticles (NP), MCM-41, SBA-15, and KCC-1 were synthesized to evaluate the effect of catalyst morphology on activity and selectivity. The correlation between the different support systems and corresponding activity was studied using SEM, TEM, BET, FTIR, and TGA before and after the reaction. Among the synthesized catalysts, sulfonic acid-functionalized KCC-1 (KCC-1SO₃H) and 3-((3-(trimethoxysilyl) propyl) thio) propane-1-oxy-sulfonic acid-functionalized (KCC-1APSO₃H) showed higher conversion and selectivity for the self-condensation and cross-condensation reactions, respectively. The effects of various parameters on the activity and selectivity, such as the reaction time and temperature, were studied. The catalysts have substantial hydrolytic stability in the presence of water and retain their acidity over multiple reaction cycles. The low cost, high activity, and pronounced stability of these fibrous nano silica-based catalysts indicate a promising future application in the biorefinery industries.