Ionic-liquid-catalyzed efficient transformation of γ-valerolactone to methyl 3-pentenoate under mild conditions

Crystal structure of zwitterionic 3,3'-[1,1'-(butane-1,4-di-yl)bis-(1H-imidazol-3-ium-3,1-di-yl)]bis-(propane-1-sulfonate) dihydrate

A known N-heterocyclic carbene precursor, zwitterionic 3,3′-[1,1′-(butane-1,4-di­yl)bis­(1H-imidazol-3-ium-3,1-di­yl)]bis­(propane-1-sulfonate) crystallized as its dihydrate and was characterized by single-crystal X-ray diffraction, revealing point group symmetry for the zwitterionic mol­ecule.

The crystal structure of the title compound, C₁₆H₂₆N₄O₆S₂·2H₂O, a water-soluble di-N-heterocyclic carbene ligand precursor was determined using a single crystal grown by the slow cooling of a hot N,N-di­methyl­formamide solution of the compound. The dihydrate crystallizes in the monoclinic space group P2₁/c, with half of the zwitterionic mol­ecule and one water mol­ecule of crystallization in the asymmetric unit. The remaining part of the mol­ecule is completed by inversion symmetry. In the mol­ecule, the imidazole ring planes are parallel with a plane-to-plane distance of 2.741 (2) Å. The supra­molecular network is consolidated by hydrogen bonds of medium strength between the zwitterionic mol­ecules and the water mol­ecules of crystallization, as well as by π–π stacking inter­actions between the imidazole rings of neighbouring mol­ecules and C—H⋯O hydrogen-bonding inter­actions.

Hydration of sulfobetaine dizwitterions as a function of alkyl spacer length

The solvation and structure of bolaform dizwitterions containing two sulfobetaine moieties in concentrated aqueous solution were determined using neutron diffraction with isotopic substitution (NDIS) combined with modelling of the measured structure factors using Empirical Potential Structure Refinement (EPSR). Strongly directional local hydration was observed in the polar regimes of the dizwitterions with 48-52 water molecules shared between dizwitterion molecules in a first shell water network around each zwitterion pair. Overall, the double zwitterions were highly hydrated, providing experimental evidence in support of the potential formation of protein-resistant hydration layers at zwitterion-water interfaces.

Synthesis of γ-Valerolactone from Carbohydrates and its Applications

γ-Valerolactone (GVL) is a valuable chemical intermediate that can be obtained by catalytic reduction of levulinic acid (LA) or alkyl levulinates (AL). There are many reports on the synthesis of GVL from LA or AL. However, the demand for the large-scale synthesis of GVL requires more environmentally friendly and cost-effective production processes. This article focuses on the recent advance in the synthesis of GVL from carbohydrates or lignocellulosic biomass. In addition, application of GVL as the reaction solvents, fuel additives, and as precursor for the synthesis of jet fuel and polymer monomers is also discussed.

Methyl 4-methoxypentanoate: a novel and potential downstream chemical of biomass derived gamma-valerolactone

A potential biofuel and solvent, methyl 4-methoxypentanoate, was effectively prepared from biomass derived GVL and methanol by the catalysis of HUSY and CaCO₃.

Conversion of cellulose into isosorbide over bifunctional ruthenium nanoparticles supported on niobium phosphate

Considerable effort has been applied to the development of new processes and catalysts for cellulose conversion to valuable platform chemicals. Isosorbide is among the most interesting products as it can be applied as a monomer and building block for the future replacement of fossil resource-based products. A sustainable method of isosorbide production from cellulose is presented in this work. The strategy relies on a bifunctional Ru catalyst supported on mesoporous niobium phosphate in a H2 atmosphere under pressure without further addition of any soluble acid. Over 50 % yield of isosorbide with almost 100 % cellulose conversion can be obtained in 1 h. The large surface area, pore size, and strong acidity of mesoporous niobium phosphate promote the hydrolysis of cellulose and dehydration of sorbitol; additionally, the appropriate size of the supported Ru nanoparticles avoids unnecessary hydrogenolysis of sorbitol. Under a cellulose/catalyst mass ratio of 43.3, the present bifunctional catalyst could be stably used up to six times, with its mesoporous structure well preserved and without detectable Ru leaching into the reaction solution.