Kinetic modeling of levulinic acid hydrogenation to γ-valerolactone in water using a carbon supported Ru catalyst

Hydrogenation of levulinic acid to γ-valerolactone over anatase-supported Ru catalysts: Effect of catalyst synthesis protocols on activity

“…In the case of water as the reaction medium, substantial amounts of 4-HPA are formed, in line with our own observations and literature data [23,38,41]. Other intermediates (e.g.…”

“…2). The intramolecular esterification of 4-HPA is known to be an equilibrium reaction with an equilibrium constant of about 16 [38]. The ratio of GVL/4-HPA obtained here after 6 h of reaction is 5, indicating that the two components are not yet at equilibrium.…”

“…2), with full selectivity to GVL. No 4-HPA was detected in dioxane, as the intramolecular esterification reaction to GVL is much faster in organic solvents than in water due to equilibrium considerations (Scheme 1) [38].…”

“…Standard reaction conditions were selected based our previous results [19,38,39], and are given in Table 2. The lower reaction temperature selected for the reaction in water (90°C) compared to dioxane (150°C) reflects the surprisingly high activity of Ru-based hydrogenation catalysts under aqueous conditions, for which the underlying reasons have been recently discussed [15,17,19,38,41,42]. The hydrogen pressure was set at 45 bar for all experiments.…”

“…LA hydrogenation reactions were performed according to previously published standard conditions for water [38], and dioxane [39]. The hydrogenation reactions using water as the solvent were performed in a stainless steel batch autoclave (100 mL, Parr Instrument Company).…”