We propose that c-valerolactone (GVL), a naturally occurring chemical in fruits and a frequently used food additive, exhibits the most important characteristics of an ideal sustainable liquid, which could be used for the production of both energy and carbon-based consumer products. GVL is renewable, easy and safe to store and move globally in large quantities, has low melting (231 uC), high boiling (207 uC) and open cup flash (96 uC) points, a definitive but acceptable smell for easy recognition of leaks and spills, and is miscible with water, assisting biodegradation. We have established that its vapor pressure is remarkably low, even at higher temperatures (3.5 kPa at 80 uC). We have also shown by using 18 O-labeled water that GVL does not hydrolyze to gammahydroxypentanoic acid under neutral conditions. In contrast, after the addition of acid (HCl) the incorporation of one or two 18 O-isotopes to GVL was observed, as expected. GVL does not form a measurable amount of peroxides in a glass flask under air in weeks, making it a safe material for large scale use. Comparative evaluation of GVL and ethanol as fuel additives, performed on a mixture of 10 v/v% GVL or EtOH and 90 v/v% 95-octane gasoline, shows very similar properties. Since GVL does not form an azeotrope with water, the latter can be readily removed by distillation, resulting in a less energy demanding process for the production of GVL than that of absolute ethanol. Finally, it is also important to recognize that the use of a single chemical entity, such as GVL, as a sustainable liquid instead of a mixture of compounds, could significantly simplify its worldwide monitoring and regulation.

The multi-step conversion of sucrose to various C 5 -oxygenates and alkanes was achieved by integrating various homogeneous and heterogeneous catalytic systems. We have confirmed that the dehydration of sucrose to levulinic and formic acids is currently limited to about 30-40% in the presence of H 2 SO 4 , HCl, or Nafion NR50 in water. Performing the dehydration in the presence of a P(m-C 6 H 4 SO 3 Na) 3 modified ruthenium catalyst under hydrogen resulted in the in situ conversion of levulinic acid to c-valerolactone (GVL). Levulinic acid can be hydrogenated to GVL quantitatively by using P(m-C 6 H 4 SO 3 Na) 3 modified ruthenium catalyst in water or Ru(acac) 3 /PBu 3 / NH 4 PF 6 catalyst in neat levulinic acid. Formic acid can be used for the transfer hydrogenation of levulinic acid in water in the presence of [(g 6 -C 6 Me 6 )Ru(bpy)(H 2 O)][SO 4 ] resulting in GVL and 1,4-pentanediol. The hydrogenation of levulinic acid or GVL can be performed to yield 1,4-pentanediol and/or 2-methyl-tetrahydrofuran (2-Me-THF). The hydrogenolysis of 2-Me-THF in the presence of Pt(acac) 2 in CF 3 SO 3 H resulted in a mixture of alkanes. We have thus demonstrated that the conversion of carbohydrates to various C 5 -oxygenates and even to alkanes can be achieved by selecting the proper catalysts and conditions, which could provide a renewable platform for the chemical industry.

The selective transfer hydrogenation of levulinic acid (LA) with formic acid (FA) to 4-hydroxyvaleric acid (4-HVA) and carbon dioxide followed by the intramolecular dehydration of 4-HVA to γ-valerolactone (GVL) are key steps of the conversion of carbohydrate-based biomass to GVL, which can be used for the production of both energy and carbon-based products. LA was converted to GVL in the presence of a small excess of FA and the Shvo catalysts {[2,5-Ph 2 -3,4-(Ar) 2 (η 5 -C 4 CO)] 2 H}Ru 2 (CO) 4 (μ-H)]} (Ar = p-MeOPh (1a), p-MePh (1b), Ph (1c)). The reactions were performed at 100 °C with yields higher than 99% after a few hours. The formation of 1,4-pentanediol and 2-methyltetrahydrofuran remained below detection limits. The only side products were water and carbon dioxide, as expected, which were easily removed and separated from the product GVL under reduced pressure. The Shvo catalyst 1c was recycled four times without losing catalytic activity, and the product GVL was isolated each time as a colorless liquid of 99.9% purity with only trace amounts of water present.

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ABSTRACT:The sulfuric acid-catalyzed conversion of paper wastes in gamma-valerolactone (GVL) or dioxane leads to the formation of levulinic acid (LA) and formic acid (FA), which can be converted to GVL by transfer-hydrogenation using the Shvo catalyst in situ or separately. The isolation of LA and FA was assisted by the neutralization of the sulfuric acid with ammonia to form a biphasic system. While the ammonium sulfate and most of FA and some of LA were in the aqueous phase, the organic solvent-rich phase contained most of the LA and some of the FA. GVL was used as an illuminating liquid in glass lamps for hours without the formation of noticeable smoke and/or odor even in a small room. While neat GVL can be used for the safe but somewhat slow lighting of charcoal, the ignition with different mixtures of GVL (95 or 90 vol %) and ethanol (5 or 10 vol %) was reduced to a convenient few seconds. Ignition tests of charcoal combined with emission analyses revealed that by increasing the ethanol content to 10 vol % the relative VOC emission can be decreased by 15% compared to the commercial lighter fluids.