| 摘要 |
<p>Chlorofluoroalkanes by (chloro) fluorination of tetrachloro-methane or ethylene in presence of black chromium oxide. D5-. The process comprises reacting CCl4 with HF at 175-425 C or C2Cl4 with HF and Cl2 (Cl2:C2Cl4 molar ratio 0.8:1 to 1.8:1) at 275-475 C in presence of black oxide platelets, with O2:Cr atomic ratio 1.5:1 but 3:1. This catalyst is prepared by heating Cr2O3 to 300 C, Cr(OH)3 to 350 C, Cr carbonate or other easily-decomposed Cr salt in air or O2 or by heating black oxide many times with H2 and O2 alternately at 450 C. The use of black oxide of chrome gives better catalyst activity and consequent high conversion and yields.</p> |
