SILICA GEL-SUPPORTED POLYPHOSPHORIC ACID (PPA/SIO2) AS AN EFFICIENT AND REUSABLE CATALYST FOR CONVERSION OF CARBONYL COMPOUNDS INTO OXATHIOACETALS AND DITHIOACETALS

A simple and efficient method for the conversion of carbonyl compounds to oxathioacetals and dithioacetals by using polyphosphoric acid supported on silica gel (PPA/SiO 2 ) as an acid catalyst have been developed. PPA/SiO 2 is easily recovered from the reaction mixture and reused without a decrease in catalytic activity.