Isobutyric acid ( or isovaleric acid) has been synthesized by oxidation of isobutyl alcohol ( or isopentyl alcohol) using Mr-PTEBAS or Mr-PTBBAS as phase transfer cata lyst ( PTPC ) in su lfuric acid acid ity Cr(VI) oxidating medium. The PTPC was retrieved. and the oxidant Cr(VI) was obtained electrolytically from Cr( III ) salt solution resulted from above oxidation reaction . The tech nological condit ions have been researched, on the optimum condi tions, the yield is more tha n 90%.