New generation biofuels: γ-valerolactone into valeric esters in one pot

Abstract

Ethyl valerate and pentyl valerate, suitable as a gasoline additive and diesel component respectively, can be obtained in a one pot one step reaction from γ-valerolactone, readily available from lignocellulosic biomass. The reaction takes place in ethanol under H₂ through nucleophilic addition of the alcohol to the carboxylic group giving hydroxypentanoate, dehydration to pentenoate and hydrogenation to the saturated ester. The bifunctional catalyst used consists of a non noble metal, namely copper, supported on an amorphous weakly acidic material, therefore representing an interesting alternative to Pt–zeolite catalysts. Pentyl valerate can be obtained in one pot with conversions >90% and selectivity up to 83%.