Oxygenated biofuels: Synthesis of fatty acid solketal esters with a mixture of sulfonated silica and (Bu4N)(BF4) catalyst

Abstract

Amorphous SiO2-SO3H [1] with a small surface area and 1.32-mmol H+/g was used for the one-step preparation of solketal from glycerol and acetone; a 20%-w/w catalyst mixture (10% [1] and 10% (Bu4N)(BF4) was found to be very efficient for the synthesis of disolketal ether and of oxygenated biofuels fatty acids solketal esters (FASEs), by direct esterification of the caprylic, lauric, stearic, oleic and linoleic acids with solketal in a 4:1 acid:solketal ratio in refluxing toluene. Solketal acetate was also produced in quantitative yields.