Reactivity of levulinic acid and cellulose with butenes for the formation of butyl levulinates

SSCI-VIDE+CDFA+ADO:NES:FRAInternational audienceAmong the chemicals that can be obtained from renewable biomass, levulinic esters and more especially butyl levulinates are recognized as potential alternatives to some petro-chemicals for use as additives (fuel, flagrance), solvents and also platforms for fine chemistry. Also their more interesting formation from raw biomass (cellulose) has been reported. The main route involves acid-catalyzed esterification of levulinic acid (ex-cellulose) with an alcohol.As an alternative it may be possible to form butyl levulinates using olefins instead of alcohols as alkylating agent. This would have the advantage to avoid the concomitant formation of dialkyl ether and water that limits the esterification efficiency.We will present here an in-depth study on the formation of butyl levulinates from levulinic acid and cellulose using butene isomers as alkylating reagent, in the presence of an acid catalyst.We particularly showed that the reaction can proceed in the absence of solvent. This allowed a full recovery of the formed butyl levulinates by a simple work up procedure. Stoichiometric formation is possible in a non-polar solvent able to solubilize the olefin, and even at room temperature for iso-butene. Note that it was therefore possible to obtain ter-butyl levulinate in high yields, which is not possible using tert-butanol as esterifying agent. gamma-Butyrolactone was identified as a promising green bio-based solvent needed for reaction extension to solid reactants like cellulose and preliminary results will be presented.Results of the use of solid acid catalysts will also be presented showing a high potential of efficiency and reusability under low temperature conditions