A facile conversion of furfural to novel tetrahydrofurfuryl hemiacetals

An entirely new and highly selective method for preparation of novel tetrahydrofurfuryl hemiacetals is described. The process is based on the catalytic hydrogenation of furfural in an alcohol under mild reaction conditions and at very short reaction times. As a highly active and selective catalyst palladium supported on calcium carbonate is used. Basic sites of the catalyst support enhance the formation of furfuryl hemiacetal as the intermediate which is instantaneously hydrogenated into stable tetrahydrofurfuryl hemiacetal. About 85-90 % yields of tetrahydrofurfuryl hemialkylacetals can be achieved within 20 min by reaction of furfural in alcoholic solutions at 60 degrees C and 0.3 MPa of hydrogen. The mechanism of reductive acetalization of furfural into tetrahydrofurfuryl hemialkylacetals is proposed.