Method for preparing high-activity pentafluoroethane chromium-based catalyst through segmented roasting and segmented fluorination

• Main Authors: WANG WEI, WANG XIN, TIAN DINGLEI, ZHU HUI, DU RONGLI, DING CHEN, LI HANSHENG, NIU WEI
• Format: Patent
• Language: Chinese; English
• Published: 21.04.2020
• Subjects: ACYCLIC OR CARBOCYCLIC COMPOUNDS; CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOIDCHEMISTRY; CHEMISTRY; METALLURGY; ORGANIC CHEMISTRY; PERFORMING OPERATIONS; PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL; THEIR RELEVANT APPARATUS; TRANSPORTING

The invention relates to a method for preparing a high-activity pentafluoroethane chromium-based catalyst through segmented roasting and segmented fluorination. The high activity, high selectivity andlong service life of the chromium-based catalyst are achieved by regulating the fluorination process and the roasting process and adding auxiliaries. A catalyst precursor is obtained through segmented roasting, namely the catalyst precursor is firstly roasted in nitrogen, chromium hydroxide of the catalyst precursor is fully thermally decomposed to obtain amorphous chromium oxide, and then the amorphous chromium oxide is roasted in the air, so that weak oxidation of the catalyst is guaranteed, and the catalyst is kept to have high valence. Fluorination is carried out in sections in the fluorination process, moisture and heat generated in the fluorination process are removed in time, the fluorination degree is controlled, enough fluorine atoms are kept in the catalyst, the fluorination time is short, the phase cha