Abstract |
여러가지 불균일 촉매(Rh/Al2O3, Pd/C, Ni, Al2O3, Active carbon)를 이용하여 CFC-113a의 가수소 분해반응을 액상과 기상에서 각각 조사하였다. 액상반응에서는 각 촉매에 따라 반응성은 차이가 났지만, 95% 이상의 높은 선택성으로 HCFC-123(CF3CHCl)을 주었다. 특히 Al2O3가 액상반응에서 상당히 높은 반응성과 선택성을 보인 것은 주목할 만하다. 기상반응의 경우, 전이금속이 포함된 촉매(Pd/C, Pt/C)를 사용하였을 때에는 과수소화물인 HCFC-133a(CF3CH2Cl)와 HFC-143a(CF3CH3)가 생성되었다. 한편, 액상반응에서 활성을 보이던 Al2O3는 기상반응에서는 거의 반응성을 보이지 않았다. Al2O3의 경우 용매로 THF를 사용하였을 경우에는 비교적 부반응 없이 깨끗하게 반응이 진행되었지만, MeOH를 사용하였을 때는 용매로 부터 CH3OCH3과 CH3CH2OCH3 등이 생성되면서 가수소 분해반응이 진행되었다. 따라서 액상반응에서는 용매의 역할이 중요한 것으로 해석하였다. Hydrogenolysis reactions of CFC-113a catalyzed by various heterogeneous catalysts (Rh/Al2O3, Pd/C, Ni, Al2O3, Active carbon) were investigated in the liquid and gas phases. In the liquid phase reaction, different catalysts showed different activities, but all catalysts used gave high selectivities toward HCFC-123 over 95%. It was noticeable that the neutral Al2O3 showed both a high activity and a selectivity in the liquid phase reaction. In the gas phase reaction, transition metals on carbon(Pd/C, Pt/C) were so active for hydrogenolysis of CFC-113a that they even catalyzed the production reaction of overhydrogenated compounds such as HCFC-133a(CF3CH2Cl) and HFC-143a(CF3CH3). Al2O3, which showed the high activity in the liquid phase reaction, did not show a remarkable activity. When Al2O3 was used in the liquid phase reaction, the hydrogenolysis of CFC-113a proceeded without any side products in THF. However, the same reaction in MeOH produced side products, such as CH3OCH3 and CH3CH2OCH3 from solvent. Based on this result, including heterogeneous catalysts, it was concluded that the solvent played an important role in the liquid phase reaction. |
