Selective hydroconversion of levulinic acid to γ-valerolactone or 2-methyltetrahydrofuran over silica-supported cobalt catalysts. Issue 9 (17th April 2019)

• Record Type: Journal Article
• Authors: Novodárszki, Gyula; Solt, Hanna E.; Valyon, József; Lónyi, Ferenc; Hancsók, Jenő; Deka, Dhanapati; Tuba, Róbert; Mihályi, Magdolna R.
• Is Part Of: Catalysis science & technology. Volume 9:Issue 9(2019)
• Page Start: 2291
• Page End: 2304
• Publication Date: 2019-04-17
• Subjects: Catalysis -- Periodicals; 541.395
• DOI: 10.1039/c9cy00168a
• Languages: English
• ISSNs: 2044-4753

Abstract

Abstract : Levulinic acid can be hydrodeoxygenated either to γ-valerolactone or to 2-methyltetrahydrofuran over the Co/SiO2 catalyst. Selectivity was controlled by the hydrogenation activity of the catalyst. Abstract : Solvent-free hydroconversion of levulinic acid (LA) was studied over Co/silica catalysts by applying a flow-through fixed-bed microreactor. Consecutive hydrogenation/hydrogenolysis and dehydration reactions proceeded over the catalyst having Co 0 metal and CoO x Lewis acid active sites. As a first step, LA was dehydrated to form an angelica lactone (AL) intermediate. Because dehydration of LA is a facile reaction, the selectivity was controlled by the hydrogenation/hydrogenolysis activity of the catalyst. At 200 °C and 30 bar total pressure in the steady state, the catalyst could only saturate the double bond of the AL ring. Thus, γ-valerolactone (GVL) was obtained with 98 mol% yield at full LA conversion. However, at temperatures ≥225 °C, the hydrogenation activity was high enough to cleave the GVL ring and obtain 2-methyltetrahydrofuran (2-MTHF) with a stable yield of about 70 mol%. FT-IR spectroscopic examination of the adsorbed LA showed the formation of H-bound LA and also surface carboxylate. 4-Hydroxy-3-pentenoate and 4-hydroxypentanoate were substantiated as surface intermediates of lactone formation by dehydration.