Facile Synthesis of Ethyl-4-ethoxy Pentanoate as a Novel Biofuel Additive Derived from γ-Valerolactone

The synthesis of new biomass-derived ethers is of great interest for the development of biofuels and biofuel additives. In this study, we report the facile synthesis of a novel bioether ethyl-4-ethoxy pentanoate (EEP) from γ-valerolactone (GVL), a well-known biomass platform compound. The formation of EEP involves the etherification of ethyl-4-hydroxyl pentanoate (EHP) formed by GVL ring opening catalyzed by H-β-zeolite in ethanol. When operated at 140 °C for 2 h under autogenous pressure, the highest EEP yield of 55% was achieved at 62% GVL conversion and 89% EEP selectivity. The EEP yield was significantly improved to 86% by increasing the reaction temperature to 160 °C, where the EEP selectivity reached ∼97%. The extraordinarily high selectivity to EEP over H-β is likely correlated to its unique structure, which has strong Lewis acid sites as well as an optimal pore size.