Zeolites as efficient catalysts for synthesis of cyclopentyl ethyl ether

Hereby, we applied a previously developed method of zeolite-catalyzed gas phase synthesis of unsymmetric ethers for a homologous compound to previously synthesized cyclopentyl methyl ether (CPME)—cyclopentyl ethyl ether (CPEE). This synthesis utilized two bio-based alcohols as feed—cyclopentanol (CYPol) in a mixture with ethanol. From a tested group of commercially available zeolites (FER, MOR, BEA, Y, ZSM-5) the best CYPol conversion and selectivity to CPEE was achieved with medium-pore ZSM-5. We further used this zeolite to investigate the effect of reaction temperature and Si/Al ratio, as well as stability and recyclability of the catalyst. At optimized reaction conditions, we achieved selectivity to CPEE of 72% at CYPol conversion of almost 90%. High reaction temperatures, as well as high acid site concentrations in zeolite lead to favoring CYPol dehydration into cyclopentene over etherification. The catalyst exhibited high stability and good recyclability by calcination. We achieved comparable CPEE selectivity at CYPol conversion under mild reaction conditions to the previously documented CPME synthesis, which is a novel green solvent that utilizes a toxic reagent (methanol) for its production.