“…The heterogeneous catalysts reported include metal oxides, such as ZrO 2 [4,7], metals, such as nickel powder, palladium powder, cast iron shavings, S steel shavings [7,8], zeolites [9], exchange resins [4,10], and salts, such as sulfated zirconia [11,12]. Based on the literature, the heterogeneous catalysts that showed the best performance seem to be zeolites, such as ETS-10.…”