Effects of gas- and solid-phase additives on oxidative dehydrogenation of propane on strontium and barium hydroxyapatites Original Research Article

Effects of the introduction of tetrachloromethane (TCM) into the feedstream for the oxidative dehydrogenation of propane have been investigated on strontium and barium hydroxyapatites (SrHAp and BaHAp) with and without treatment with Cu2+ and Pb2+. Activities on SrHAp were greater than those on BaHAp in the absence of TCM. Upon adding TCM into the feedstream for propane oxidation on both SrHAp and BaHAp, the conversion of propane decreased while the selectivity to propylene increased with increasing time-on-stream, as observed in the oxidation of other alkanes on hydroxyapatites. While the treatment of both hydroxyapatites with lead resulted in the decrease of the yield of propylene regardless of the addition of TCM, activities on those catalysts doped with copper were improved in the presence of TCM. Particularly SrHAp treated with Cu2+ afforded approximately 80% selectivity to propylene at 16% conversion of propane at 0.5 h on-stream with TCM and this activity was kept for 6 h on-stream. A direct contribution of TCM to control of the reduction of Cu2+ in the catalyst leads to the improvement of the catalytic performance.