comprise a solid acid such as a zeolite examples of suitable zeolites include zsa 5 mordenite beta ferrierite and zeolite y additionally the catalyst may comprise a super acid examples of suitable super acids include sulfonated phosphated or fluorinated forms of zirconia titania alumina silica alumina and or clays in another embodiment the catalyst may comprise a solid base examples of suitable solid bases include metal oxides metal hydroxides and or metal carbonates in particular the oxides hydroxides and carbonates of alkali metals alkaline earth metals transition metals and or rare earth metals are suitable other suitable solid bases are layered double hydroxides mixed metal oxides hydrotalcite clays and or combinations thereof in yet another embodiment the catalyst can also comprise an alumina such as alpha alumina it should be noted that solid biomass materials generally contain minerals it is recognized that some of these minerals such as potassium carbonate can have catalytic activity in the conversion of the biomass material even though these minerals are typically present during the chemical conversion taking place in the biomass conversion reactor 16 they are not considered catalysts the biomass feed system 14 introduces the biomass feedstock into a biomass conversion reactor 16 in the biomass conversion reactor 16 biomass is subjected to a thermochemical conversion reaction that produces bio oil the reactor 16 can be any system or device capable of thermochemically converting biomass to bio oil the biomass conversion reactor 16 can be for example a fluidized bed reactor a cyclone reactor an ablative reactor or a riser reactor in one embodiment the biomass conversion reactor.