Hydrodechlorination of CCl4 over Pt/γ-Al2O3

Hydrodechlorination of Tetrachloromethane Over Supported Platinum Catalysts. Effects of Hydrogen Partial Pressure and Catalyst’s Screening Protocol on the Catalytic Performance

“…Carbon-containing species leave (as methane) all tested catalysts at much higher temperatures. Therefore these carbonaceous deposits should be regarded as most effective active site blockers, in agreement with others [5,6,8,22]. Very low amounts of desorbed HCl and CH 4 from a medium-dispersed Pd/SiO 2 catalyst (S8, fraction exposed [FE] = 0.264, Fig.…”

“…Very good HdCl performance of highly dispersed Pt/ Al 2 O 3 catalysts was reported by various groups [5][6][7]. Choi et al [5] showed that the kind of metal precursor is more important factor in shaping the HdCl behavior than the size of metal particles.…”

“…It must be recalled that the H 2 /CCl 4 molar ratio *7 was intentionally used by us because a similar reactant ratio was used in the studies we wished to refer to [2,3]. However, it is well known that the H 2 /CCl 4 molar ratios higher than 7 reduce catalyst deactivation [5][6][7]. The aim of this work was the reinvestigation of the same series of alumina-and silica-supported platinum catalysts (as in [1]) in the HdCl of CCl 4 , at different reaction temperatures and H 2 /CCl 4 molar ratios.…”

Hydrodechlorination of carbon tetrachloride over PtNaX zeolite: Deactivation studies

“…This high selectivity to CH 4 can be assigned to the stronger electron-deficient character showed by small platinum particles, as the particles usually obtained in zeolite supercages. This behavior can be ascribed to an intrinsic size effect or to a metal-support interaction [20,21]. It is important to point out that from the environmental point of view, methane is a much less toxic product and therefore is more interesting than CHCl 3 or other chlorinated products.…”

Supported platinum–gallium catalysts for selective hydrodechlorination of CCl4

“…Supported noble metal catalysts have been used for the hydrodechlorination of CCl 4 either in liquid phase [7][8][9][10][11] or gas phase [12][13][14][15][16][17][18][19][20][21][22]. In the pioneer work of the hydrodechlorination of CCl 4 over Pt/-Al 2 O 3 [12], some details on the reaction pathway are given, suggesting that the reaction proceeds by two parallel routes: one route is a single step addition of hydrogen to an adsorbed * CCl 3 species to form CHCl 3 selectively and the second is a concerted addition of hydrogen atoms to adsorbed * CCl 3 with no desorption of intermediates to generate CH 4 eventually.…”