Silica-supported Ni catalyst (6.6 wt% Ni) was prepared and tested in solvent-free hydroconversion of levulinic acid (LA) using flow-through fixed-bed tube-type microreactor at 250 and 275 °C in the pressure and space time range of 1–30 bar and 0.1–1.0 g cat g LA −1 h, respectively. The catalyst was characterized by XRD, adsorption/desorption N 2 isotherms, temperature-programmed H 2 -reduction (H 2 -TPR), FT-IR spectra of adsorbed pyridine (Py), and temperature-programmed H 2 desorption (H 2 -TPD). At 250 °C and 1 bar total pressure LA was dehydrated to α-angelica lactone (AL) intermediate that was hydrogenated to γ-valerolactone (GVL). At space time 0.25 g cat g LA −1 h 82% GVL selectivity was achieved at virtually full LA conversion. The GVL became partially converted to pentanoic acid (PA). At longer space time, 1.0 g cat g LA −1 h, the PA selectivity increased to 37%. At pressure > 1 bar the favored reaction of GVL was the hydrogenolysis of its ester bond and dehydration of the intermediate 1,4-pentanediol (1,4-PD) to 2-methyltetrahydrofuran (2-MTHF). At 250 °C and 30 bar the yield of 2-MTHF was 56 mol%. The product distribution is controlled by the relative activity of the Ni/SiO 2 catalyst in the hydrogenolysis of the GVL C–O bonds.
ASJC Scopus subject areas
- Physical and Theoretical Chemistry