- 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
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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.
- Geboers, Jan,Wang, Xingyu,De Carvalho, Alex Bruno,Rinaldi, Roberto
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- Surface species of supported ruthenium catalysts in selective hydrogenation of levulinic esters for bio-refinery application
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Several supported noble metal catalysts were screened for the hydrogenation of methyl levulinate to c-valerolactone (GVL). Among these catalysts 5 % Ru/C showed the highest conversion of 95 % of methyl levulinate with 91 % selectivity to GVL. A detailed characterization was carried out using TPR, XRD, XPS and BET techniques. XPS studies revealed that higher extent of Ru0 species in case of carbon supported Ru was responsible for its higher hydrogenation activity as compared to Ru on other supports. Effect of process parameters such as temperature, H2 pressure, catalyst and substrate concentration and metal loading on methyl LA conversion and selectivity to GVL also has been studied. 5 % Ru/C catalyst was found to be stable up to five reuses.
- Hengne,Biradar,Rode
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- Tetranuclear ruthenium clusters anchored on polyoxometalates catalyze the hydrogenation of methyl levulinate in water
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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
- Chen, Manyu,Cui, Kai,Hou, Zhenshan,Peng, Qingpo,Qiao, Wencheng,Wang, Jiajia,Wei, Xinjia,Yao, Yefeng,Zhao, Xiuge
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supporting information
p. 21215 - 21224
(2021/12/04)
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- Ammonia borane enabled upgrading of biomass derivatives at room temperature
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Simplifying biomass conversion to valuable products with high efficiency is pivotal for the sustainable development of society. Herein, an efficient catalyst-free system using ammonia borane (AB) as the hydrogen donor is described, which enables controllable reaction selectivity towards four value-added products in excellent yield (82-100%) under very mild conditions. In particular, the system is uniquely efficient to produce γ-valerolactone (GVL) at room temperature. Combined in situ NMR and computational studies elucidate the hydrogen transfer mechanism of AB in methanol, the novel pathway of GVL formation from levulinate in water, and a competitive mechanism between reduction and reductive amination in the same system. Moreover, carbohydrates are converted directly into GVL in good yield, using a one-pot, two-step strategy. Products of a rather broad scope are prepared within a short reaction time of 30 min by using this catalyst-free strategy in methanol at room temperature. This journal is
- Meier, Sebastian,Riisager, Anders,Yang, Song,Zhao, Wenfeng
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supporting information
p. 5972 - 5977
(2020/11/03)
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- Screening of Solvents, Hydrogen Source, and Investigation of Reaction Mechanism for the Hydrocyclisation of Levulinic Acid to Γ-Valerolactone Using Ni/SiO2–Al2O3 Catalyst
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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.]
- Gundekari, Sreedhar,Srinivasan, Kannan
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p. 215 - 227
(2018/12/13)
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- Sodium Ion as the Most Essential and Effective Element for the Enantio-Differentiating Hydrogenation of Prochiral Ketones over Tartaric Acid Modified Ni Catalyst
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Abstract: In order to investigate the role of metal ions on a tartaric acid modified nickel catalyst, the enantio-differentiating hydrogenations of methyl acetoacetate and methyl levulinate were carried out. The effects of the addition of 17 metal salts of acetic acid on the enantio-selectivity and the hydrogenation rate were investigated during the hydrogenation of methyl acetoacetate. Among the examined metal salts, the addition of NaBr caused the great increase in the enantio-selectivity and the hydrogenation rate during the hydrogenations of both methyl acetoacetate and methyl levulinate. Based on the strength of the interaction between the metal salts of tartaric acid and the substrate, the sodium salts would have the strongest interaction with the substrate, hence, this would be attributed to the highest enantio-selectivity and hydrogenation rate for the sodium salts of tartaric acid. Graphical Abstract: [Figure not available: see fulltext.]
- Osawa, Tsutomu,Tanabe, Yuya,Fujiwara, Manabu
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p. 686 - 692
(2017/03/08)
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- Liquid phase hydrogenation of methyl levulinate over the mixture of supported ruthenium catalyst and zeolite in water
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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.
- Nadgeri, Jayprakash M.,Hiyoshi, Norihito,Yamaguchi, Aritomo,Sato, Osamu,Shirai, Masayuki
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p. 215 - 220
(2014/01/06)
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- Single pot conversion of furfuryl alcohol to levulinic esters and γ-valerolactone in the presence of sulfonic acid functionalized ILs and metal catalysts
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Ionic liquids functionalized with acidic anions, HSO4, ClSO 3H, PTSA, TFA (MIm), HSO4 and TFA (NMP) were found to efficiently (99% conversion) catalyze the alcoholysis of furfuryl alcohol (FAL) in the presence of methanol, ethanol, n-butanol and isopropyl alcohol (IPA) to the corresponding levulinic acid esters under mild temperature (90-130 °C) conditions. The extended alkyl chain length of [MIm] using 1,4-butane sultone enhanced the Bronsted acidity of [BMIm-SH][HSO4] catalyst resulting into the highest selectivity of >95% to Me-LA. An increase in both temperature and catalyst concentration increased the furfuryl alcohol conversion and selectivity to levulinate esters. In contrast, an increase in the substrate concentration from 5 to 15% caused a decrease in Me-LA selectivity due to accumulation of intermediate ethers of furfuryl alcohol. Using a combination of [BMIm-SH][HSO4] and 5% Ru/C catalyst, direct conversion of FAL to γ-valerolactone (GVL) is shown for the first time. A complete conversion of FAL with the highest selectivity of 68% to GVL could be achieved under optimum conditions while higher Ru loading enhanced the GVL selectivity to 94% in the hydrogenation step of this tandem approach. Our catalyst system could be efficiently recycled five times retaining the original activity and selectivity levels.
- Hengne, Amol M.,Kamble, Sumit B.,Rode, Chandrashekhar V.
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p. 2540 - 2547
(2013/09/12)
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- Systematic investigations on the reduction of 4-aryl-4-oxoesters to 1-aryl-1,4-butanediols with methanolic sodium borohydride
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4-Aryl-4-oxoesters undergo facile reduction of both the keto and the ester groups with methanolic NaBH4 at room temperature to yield the corresponding 1-aryl-1,4-butanediols whereas 4-alkyl-4-oxoesters furnish the corresponding 1,4-butanolides via selective reduction of the keto moiety. Results of a detailed and systematic investigation of the reaction are described.
- Chaudhuri, Subrata Kumar,Saha, Manabendra,Saha, Amit,Bhar, Sanjay
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scheme or table
p. 748 - 755
(2011/01/03)
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- SELECTIVE REDUCTION OF KETOESTERS TO HYDROXYESTERS WITH THE USE OF LITHIUM ALUMINUM HYDRIDE IN THE PRESENCE OF SILICA GEL
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Lithium aluminum hydride, in the presence of a small amount of silica gel, has been found to be a versatile and highly selective reagent for reduction of various ketoesters to the corresponding hydroxyesters in fair yields.
- Kamitori, Yasuhiro,Hojo, Masaru,Masuda, Ryoichi,Inoue, Tatsuro,Izumi, Tatsuo
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p. 4585 - 4588
(2007/10/02)
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