In fluorous biphase system, Hf[N(SO2C8F17)(2)](4) has been found to be an efficient catalyst for the Prins reaction of ce-methyl styrene with aldehydes at low catalytic loading. The reaction proceeds smoothly and affords the corresponding 1,3-dioxanes in good yields. The catalyst is selectively soluble in lower fluorous phase and can be recovered simply by phase separation. Furthermore, the recovered fluorous phase containing catalyst can be recycled 17 times with yields consistently above 80%.