Studies on the Reactions of Lactone Intermediates Derived from Levulinic Acid: Telescoped Routes to Higher Levulinate Ester Biofuels.

The development of efficient strategies for the synthesis of levulinate esters is of significant current interest due to their potential as biofuels and fuel additives. Herein, we report a novel strategy to access levulinate esters derived from higher alcohols directly from levulinic acid through the in situ generation of lactone intermediates employing commercial heterogeneous catalysts, such as Amberlyst-15. This strategy employs a telescoped approach in which the lactonization/ring-opening reactions are combined into an operationally simple one-pot procedure. This strategy is advantageous as it employs a readily available and inexpensive catalyst and proceeds in short reaction times to produce excellent yields of higher levulinate esters with high selectivity. Furthermore, the Amberlyst-15 catalyst is fully recyclable and can be reused without loss of activity or selectivity.