METHOD OF SYNTHESIS OF AROMATIC FLUOROHYDROCARBONS Russian patent published in 2000 - IPC

FIELD: organic chemistry, chemical technology. SUBSTANCE: aromatic fluorohydrocarbons, for example, 1,2-difluorobenzene, 2,3-difluorotoluene, 3,4-difluorotoluene and 1-fluoro-2-trifluoro-methylbenzene are synthesized by high-temperature pyrolysis of vinylfluorocyclobutenes of the general formula: where R₁, R₂, R₃, R₄ - H or CH₃; R₅ means F, Cl or CF₃; R₆ means F or Cl. Pyrolysis is carried out at 600-800 C in the presence of steam. Hydrogalogenides in reaction steam-vapor mixture are neutralized by ammonia counter flow. Process is performed in continuous regime. EFFECT: high selectivity of formation of end compounds. 3 cl, 1 dwg, 7 ex