An Original Catalytic Reactor Coupled with Tubular Membrane to Efficiently Produce Biofuels by Etherification of Glycerol with TBA

An original batch reactor, coupled with a water permselective membrane, to efficiently perform the glycerol etherification reaction with TBA (tert-butyl-alcohol) is proposed. The reaction was carried out under mild reaction conditions (TR = 80°C) by using solid acid catalysts. The water was removed from the reaction medium by recirculation of the gas phase through the membrane. The water formed during the reaction was collected by condensation to control the presence of reactants and products in the permeate phase. The results obtained have clearly shown the significant benefits obtainable by using the membrane both in terms of glycerol conversion and poly-ethers selectivity. Under the best reaction conditions, almost a total glycerol conversion was reached with a yield to di- and tri- ethers close to 80 wt.%. The flow rate of both gas recirculation and permeate sides affects the water permeation and consequently glycerol conversion and products selectivity. At the end of reaction, in the permeate only a few percentage of TBA and ethers were found, so confirming that the membrane works with very high selectivity to water.