126252-14-0Relevant articles and documents
Densification of biorefinery schemes by H-transfer with Raney Ni and 2-propanol: A case study of a potential avenue for valorization of alkyl levulinates to alkyl γ-hydroxypentanoates and γ-valerolactone
Geboers, Jan,Wang, Xingyu,De Carvalho, Alex Bruno,Rinaldi, Roberto
, p. 106 - 115 (2014)
Alkyl γ-hydroxypentanoates and γ-valerolactone are promising platform chemicals that can be produced from alkyl levulinates in the lignocellulosic biorefinery. Accordingly, this report aims to provide in-depth insight into the molecular aspects involved in the conversion of alkyl levulinates by H-transfer catalyzed by Raney Ni and using 2-propanol as an H-donor and solvent. We demonstrate this methodology as a highly flexible approach in regard to the high degree of control over the product selectivity. In fact, up to 90% yield of alkyl γ-hydroxypentanoates is obtained at temperatures as low as 298 K. In turn, 94% yield of γ-valerolactone is achieved at 393 K. In order to shed light on the fundamental aspects of this chemical route, we address: (1) the energetics of the transfer vs. conventional hydrogenation of methyl levulinate, (2) the thermal stability of methyl γ-hydroxypentanoate in the absence and in the presence of solid catalysts, and (3) the stability of Raney Ni in the conversion of several alkyl levulinates. Lastly, a process concept based on the current results is also proposed. This concept provides a comprehensive overview of the practical possibilities of this process as part of the lignocellulose-based biorefineries.
Tetranuclear ruthenium clusters anchored on polyoxometalates catalyze the hydrogenation of methyl levulinate in water
Chen, Manyu,Cui, Kai,Hou, Zhenshan,Peng, Qingpo,Qiao, Wencheng,Wang, Jiajia,Wei, Xinjia,Yao, Yefeng,Zhao, Xiuge
supporting information, p. 21215 - 21224 (2021/12/04)
Novel ionic materials derived from ruthenium cluster cation and tungstoaluminate anions have been developed and are proved to be robust, efficient and recyclable catalysts toward the selective hydrogenation of methyl levulinate (ML) to gamma-valerolactone (GVL) or methyl 4-hydroxypentanoate (4-HPTM) by tuning the acidity. The structure and properties of the catalysts were characterized using elemental analysis, 1H NMR, 27Al NMR, FT-IR, X-ray diffraction, and pyridine absorbed FT-IR, etc. The catalysts not only afforded excellent conversion and selectivity for GVL (99%) or 4-HPTM (88%) in the aqueous phase under very mild conditions (25 °C) but also showed good recyclability in five consecutive cycles without any significant loss in catalytic activity. In contrast to the direct intramolecular esterification of 4-HPTM in most previous reports, further characterization revealed that intramolecular cyclization proceeded via a metal and counterion (tungstoaluminate)-assisted mechanism on the anchored Ru cluster catalyst; moreover, the strong acidity on the catalysts can hamper the conversion of 4-HPTM into GVL. This rendered the Ru cation complex/tungstoaluminate ionic materials a potential candidate for the efficient production of either GVL or 4-HPTM from ML hydrogenation under very mild conditions. This journal is
Screening of Solvents, Hydrogen Source, and Investigation of Reaction Mechanism for the Hydrocyclisation of Levulinic Acid to Γ-Valerolactone Using Ni/SiO2–Al2O3 Catalyst
Gundekari, Sreedhar,Srinivasan, Kannan
, p. 215 - 227 (2018/12/13)
Abstract: Commercial 65% Ni/SiO2–Al2O3 (Ni/SA) catalyst was investigated for hydrocyclisation of levulinic acid (LA) to γ-valerolactone (Gvl) in presence of different hydrogen sources such as molecular hydrogen, isopropyl alcohol (IPA), and formic acid. At optimized reaction condition (200?°C, 10?bar H2 for 30?min), the Ni/SA catalyst showed 100% yield of Gvl using molecular H2 in tetrahydrofuran (THF) medium. The catalyst also exhibited 99% yield of Gvl in IPA through catalytic transfer hydrocyclisation of LA at 200?°C in 15?min. Further, the hydrocyclisation was successfully demonstrated in continuous mode using molecular hydrogen for 20?h time-on-stream which showed 98–99% conversion of LA with 100% selectivity of Gvl at optimized reaction condition in THF medium. Graphical Abstract: [Figure not available: see fulltext.]
Liquid phase hydrogenation of methyl levulinate over the mixture of supported ruthenium catalyst and zeolite in water
Nadgeri, Jayprakash M.,Hiyoshi, Norihito,Yamaguchi, Aritomo,Sato, Osamu,Shirai, Masayuki
, p. 215 - 220 (2014/01/06)
Liquid-phase hydrogenation of methyl levulinate was studied over graphite-supported ruthenium (Ru/graphite), zeolite-supported ruthenium, and a mixture of Ru/graphite and zeolites in water at 343 K. The final γ-valerolactone yield over the mixture of Ru/graphite and ZSM-5 showed the highest activities between Ru/graphite, Ru/ZSM-5, and the mixture of Ru/graphite and several zeolites. Methyl levulinate was hydrogenated to methyl 4-hydroxyvalerate or directly to γ-valerolactone over supported ruthenium metal sites and methyl 4-hydroxyvalerate was converted to γ-valerolactone over acid sites. The mixture of Ru/graphite and ZSM-5 contained both highly dispersed ruthenium metal particles and a number of acid sites rather than those over zeolite-supported ruthenium catalysts, which led to the highest γ-valerolactone yield.
