TETRAFLUOROETHYLENE PRODUCTION PROCESS Russian patent published in 2001 - IPC

FIELD: industrial organic synthesis. SUBSTANCE: process includes pyrolysis of difluoromethane (Chladone R22) in presence of 0.09-0.16 kg of hexafluoropropylene per 1 kg of Chladone R22, quenching of pyrolysis products, and separation of hydrogen chloride into its aqueous solution. After neutralization, compression, and condensation of pyrolysis products, multistep rectification is performed to isolate desired product fraction, fraction 1 containing Chladone R22 with 10-20% hexafluoropropylene, and fraction 2 with boiling temperature above -30^°C, at atmosphere pressure, which contains Chladones R124, R124a, RC3186, and R326. Part of fraction 1, in amounts permitting withdrawal of excess hexafluoropropylene formed in difluoromethane pyrolysis stage, is separated by water absorption. Absorbed components are further desorbed and returned into pyrolysis stage together with the rest of fraction 1. Non-absorbed gases are separated by rectification into hexafluoropropylene and azeotropic mixture of the latter with Chladone R22, which is also returned into pyrolysis stage. Absorption with water is carried out at temperature of water from 5 to 45 C, pressure from 5 to 10 atm, and weight ratio of water to pyrolysis products between 20:1 to 90:1. Desorption of gases from water is carried out by reducing pressure to 0.05-1.20 gauge atm. Water after desorption, if necessary, is cooled and reused in absorption stage. EFFECT: reduced power consumption and reduced amount of by-products. 3 cl, 2 tbl, 16 ex