| 摘要 |
<p>PURPOSE:To obtain the title substance in high selectivity by conducting the vapor-phase reaction between 1,2,2-trichloro-1,1-difluoroethane with hydrogen fluoride in the presence of a catalyst which is prepared by allowing gamma-alumina of a large surface area to carry a chromium-containing salt, then treating the product with hydrogen fluoride. CONSTITUTION:In the production of the title compound by reaction of 1,2,2- trichloro-1,1-difluoroethane with hydrogen fluoride, the catalyst is prepared by allowing gamma-alumina of more than 250m<2>/g, preferably more than 300m<2>/g of a surface area to carry a chromium compound such as chromium chloride, and treating the product with hydrogen fluoride, and the catalyst is used to effect the reaction at 250 to 350 deg.C for 5 to 100 seconds. The catalyst is excellent in the durability to give high reaction conversion and high selectivity. The reaction product is separated by distillation and the unreacting feedstock is recycled to the reaction. The subject compound is useful as a foaming agent of urethane foams and a solvent for removing flux.</p> |
