NOVEL METHOD FOR PREPARING O-DIFLUOROBENZENE

PURPOSE:To prepare the titled compound useful as a synthetic intermediate for antimicrobial agents in high yield, by adding a small amount of a silicone oil to 2-fluoro-1-benzenediazonium tetrafluoroborate in the thermal decomposition thereof. CONSTITUTION:o-Fluoroaniline is diazotized and then reacted with a fluoronating agent, e.g. borofluoric acid to give 2-fluoro-1-benzenediazonium tetrafluoroborate. A small amount, preferably about 4-5wt% based on the above-mentioned raw material, of a silicone oil is added to the 2-fluoro-1-benzenediazonium tetrafluoroborate and decomposed thermally under heating at 100- 180 deg.C, preferably 130-160 deg.C, for about 1-5hr to afford the aimed o-difluorobenzene. EFFECT:The reaction proceeds very mildly, and a reaction vessel of relatively small volume is enough.