Ha, Jeong-Myeong Kim, Daewoo Kim, Jaehoon Ahn, Byoung Sung Kim, Yunje Kang, Jeong Won 2024-01-20T17:00:21Z 2024-01-20T17:00:21Z 2021-09-02 2011-07 1093-4529 https://pubs.kist.re.kr/handle/201004/130244 The hydrodechlorination of chlorodifluoromethane (HCFC-22) was performed by a catalytic reaction and noncatalytic thermal decomposition at high temperatures of 400-800 degrees C. After 47 h of time-on-stream on a supported palladium (Pd) catalyst, the gas-phase composition of difluoromethane (HFC-32) is 41.0%, with 4.9% of the HCFC-22 remaining, indicating the conversion of up to 95.1% of HCFC-22. The supported nickel catalyst's deactivation is significant as it exhibits the low conversion of HCFC-22 under the same reaction conditions. The deactivation of the catalyst is caused by the polymerization of adsorbed methyl radicals, which competes with the formation of HFC-32. With concentrated reactants at high reaction temperatures, there was an increase in the catalytic activity; however, unwanted tar, methane, and trifluoromethane (HFC-23) by-products are also produced. The use of catalyst suppresses the formation of these by-products. Considering the compositions of the products of the catalytic and noncatalytic reactions, we demonstrate that the use of the supported-metal catalysts and hydrogen flow suppresses tar formation and lowers the required reaction temperature. English TAYLOR & FRANCIS INC CCL2F2 CFC-12 SELECTIVE HYDROGENOLYSIS CHLOROFLUOROCARBONS HYDROCONVERSION DECOMPOSITION CONVERSION FLUORIDE High-temperature hydrodechlorination of ozone-depleting chlorodifluoromethane (HCFC-22) on supported Pd and Ni catalysts Article 10.1080/10934529.2011.586262 1 JOURNAL OF ENVIRONMENTAL SCIENCE AND HEALTH PART A-TOXIC/HAZARDOUS SUBSTANCES & ENVIRONMENTAL ENGINEERING, v.46, no.9, pp.989 - 996 JOURNAL OF ENVIRONMENTAL SCIENCE AND HEALTH PART A-TOXIC/HAZARDOUS SUBSTANCES & ENVIRONMENTAL ENGINEERING 46 9 989 996 scie scopus 000293834700009 2-s2.0-79960681084 Engineering, Environmental Environmental Sciences Engineering Environmental Sciences & Ecology Article CCL2F2 CFC-12 SELECTIVE HYDROGENOLYSIS CHLOROFLUOROCARBONS HYDROCONVERSION DECOMPOSITION CONVERSION FLUORIDE HCFC-22 HFC-23 HFC-32 nickel palladium catalysis hydrodechlorination