Hydrolysis of Tetrafluoromethane (PFC-14) Using Alumina–Zirconia Catalysts Prepared Using γ-Alumina and Boehmite as Alumina Sources

The reaction rate of the hydrolysis of tetrafluoromethane (PFC-14) was measured using alumina–zirconia catalysts prepared from γ-alumina and boehmite as the alumina source. The hydrolysis rate of PFC-14 increased almost linearly with increasing alumina content, and the dependence was similar, regardless of the alumina source used. It was found that the alumina–zirconia catalyst prepared from γ-alumina had one type of acid site (acid site (I)), while the alumina–zirconia catalyst prepared from boehmite had two types of acid sites (acid site (I) and acid site (II)). These results suggested that acid site (I) contributes to the decomposition of PFC-14, and that both catalysts contain similar amounts of acid site (I). In addition, to investigate the properties of acid site (I), catalytic decomposition of isopropyl benzene was carried out in the presence of steam. As a result, it was found that the catalytic cracking reaction of isopropyl benzene in the presence of steam did not proceed on the alumina–zirconia catalyst prepared from γ-alumina. This result suggests that the acid site (I) is a Lewis acid and the acid site (II) is a Brønsted acid.