The Use of a γ-Al2O3 and MgO Mixture in the Catalytic Conversion of 1,1,1,2-Tetrafluoroethane (HFC-134a)

This paper reports the improved efficiency of 1,1,1,2-tetrafluoroethane (HFC-134a) decomposition by combined use of MgO with γ-Al2O3. While a high temperature (>900 °C) was required to achieve 90% conversion during non-catalytic pyrolysis of HFC-134a, 100% conversion of HFC-134a was achieved at 600 °C by the use of γ-Al2O3. Among the three catalysts (γ-Al2O3, MgO, and CaO) tested in this study, γ-Al2O3 showed the highest HFC-134a decomposition efficiency, followed by MgO and CaO, due to its large surface area and large amount of weak acid sites. Also with the longest lifetime among the catalysts, durability in maintaining complete decomposition of HFC-134a was shown in γ-Al2O3. The addition of MgO to γ-Al2O3 was effective in extending the lifetime of γ-Al2O3 due to the efficient interaction between HF and MgO, which can delay the deactivation of γ-Al2O3. Compared to the double bed γ-Al2O3-MgO configuration, the use of a mixed γ-Al2O3-MgO bed extended the catalyst lifetime more effectively.