Production Of Dimethylfuran From Hydroxymethylfurfural, A Biomass Derived Product, Using A Ruthenium Catalyst Coated Polymeric Membrane Reactor

Ethanol is the only currently mass produced liquid fuel from renewable sources but suffers from some limitations.  An attractive alternative is 2,5-dimethylfuran (DMF), which has physical characteristics more closely resembling those of gasoline.  Hydroxymethylfurfural (HMF) is a biomass-based platform chemical that can be hydrogenolyzed to produce DMF.  Recent work has been performed on this reaction using a copper-ruthenium catalyst with traditional reactors.  A new method is proposed using a catalyst coated polymeric membrane reactor that allows for an abundant supply of hydrogen directly to the catalytic sites on the membrane surface.  The polymeric membranes utilized are selective for hydrogen transport, thus also acting as a liquid/gas barrier.  Polyimide polymers are being investigated for high temperature stability and chemical resistance.  Suitable polymers are cast into flat sheet asymmetric membranes and characterized for hydrogen and nitrogen flux and selectivity.  The membranes are then coated with ruthenium using a spin-coating technique.  Various solvents are being explored that will act as solvents for the hydrogenolysis reactants and products, but that will not strongly interact with the polymer or affect membrane performance.  Equilibrium liquid solvent sorption and solvent desorption rates are measured for thick films.  The temperature range being investigated for this reaction is 200-220°C with a hydrogen supply pressure of one to two atmospheres.  If shown to produce significant conversion of HMF while maintaining long-term membrane reactor stability and performance, the hydrogenolysis reaction of HMF to DMF using a catalyst coated polymeric membrane may serve as a model reactor/reaction for several other biorefinery operations.