γ-valerolactone from levulinic acid and its esters: Substrate and reaction media determine the optimal catalyst

13 figures, 7 tables.-- © 2021. This manuscript version is made available under the CC-BY-NC-ND 4.0 license https://creativecommons.org/licenses/by-nc-nd/4.0Ni-based catalysts supported on sepiolite were synthesized by different preparation procedures for the production of γ-valerolactone from levulinic acid and its esters (methyl levulinate and ethyl levulinate). The optimal performance was related to the formation of tiny nickel particles. Interestingly, the reaction conditions significantly influence the reactivity of the substrates. The catalytic performance of the optimal Ni/sepiolite catalyst was compared with two catalysts of ruthenium (supported on γ-alumina or sepiolite). In all cases, the production of γ-valerolactone depends on both the substrate employed and the reaction media. Overall, the preferred reaction media using the Ni-catalyst is 2-propanol whereas pressurized hydrogen in water is the best alternative for Ru-catalysts. In both cases, a reasonable stability has been observed after 3 cycles. Finally, the use of metallic Zn in an aqueous medium to provide hydrogen could not be considered as an appropriate option due to the lack of a stable behaviour.Authors from UCM thank MINECO(MAT2017-84118-C2-2-R project) and UCM CAI center of EM. Authors from UV thank MINECO (MAT2017-84118-C2-1-R project) and FEDER for funding. A.G. thanks MINECO for the pre-doctoral grant.Peer reviewe