Enzymatic synthesis of a novel solid-liquid phase change energy storage material based on levulinic acid and 1,4-butanediol

Synthesis of 5-(Hydroxymethyl)furfural Monoesters and Alcohols as Fuel Additives toward Their Performance and Combustion Characteristics in Compression Ignition Engines

The synthesis of 5-(hydroxymethyl)furfural (HMF) and conversion to the corresponding HMF-monoesters upon certain treatment are presented with their properties that are validated in a diesel engine. With a collection of fatty acids (C8-C18) using cyanuric acid as a catalyst under mild reaction conditions, the subsequent reduction of the HMF-monoesters with NaBH₄ produced the corresponding alcohols. After purification, both HMF-monoesters and their alcohol derivatives were determined for their solubility, cetane index, heat of combustion, viscosity, and specific gravity. HMF-Capric (1-C10), HMF-Oleic (1-C18:1), HMF-Caprylic-OH (2-C8), and HMF-Oleic-OH (2-C18:1) were soluble in a neat diesel fuel. The observed highest cetane index and heat of combustion of 1-C10 and 1-C18:1 were evaluated for combustion characteristics in a single-cylinder compression ignition engine. The diesel fuel containing 3% 1-C10 displayed comparable properties during burning in terms of thermal efficiency, cylinder pressure, and heat release rate with respect to the neat diesel fuel (D100) for all usage engine speeds. In general, all tested fuels initiated their burning onset with a similar ignition delay period. The 3% 1-C10-blended diesel fuel emitted slightly higher smoke opacity but an equivalent nitric oxide level compared to those of D100. The HMF-Capric (1-C10) synthesized in this study represents a promising additive for diesel fuel. Blended fuel lubricity and other unregulated emissions upon broader engine test cycles are suggested to be accomplished in future work.

Process optimization for enzymatic production of a valuable biomass-based ester from levulinic acid

The enzymatic production of isoamyl levulinate via esterification of isoamyl alcohol (IA) and levulinic acid (LA), a biomass-based platform chemical with attractive properties, in a solvent system has been performed in this study. For such a purpose, a low-cost liquid lipase (Eversa^® Transform 2.0) immobilized by physical adsorption via hydrophobic interactions (mechanism of interfacial activation) on mesoporous poly(styrenene-divinylbenzene) (PSty-DVB) beads was used as heterogeneous biocatalyst. It was prepared at low ionic strength (5 mmol.L^-1 buffer sodium acetate pH 5.0) and 25 ℃ using an initial protein loading of 40 mg.g^-1 of support. Maximum protein loading of 31.2 ± 2.8 mg.g^-1 of support and an immobilization yield of 83% was achieved. The influence of relevant factors (biocatalyst concentration and reaction temperature) on ester production was investigated using a central composite rotatable design (CCRD). Maximum acid conversion percentage of 65% was achieved after 12 h of reaction at 40 °C, 20% of mass of heterogeneous biocatalyst per mass of reaction mixture (20% m.m^-1), and LA:IA molar ratio of 1:1.5 in a methyl isobutyl ketone (MIBK) medium. The biocatalyst retained around of 30% of its initial activity after five consecutive esterification batches under optimal experimental conditions. The proposed experimental procedure can be considered as an acceptable green process (EcoScale score of 66.5), in addition to the fact that a new strategy is proposed to sustainably produce a valuable industrial ester (isoamyl levulinate) from biomass-based materials using an immobilized and low-cost commercial lipase as catalyst.