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Deactivation behavior of Pd/C and Pt/C catalysts in the gas-phase hydrodechlorination of chloromethanes: Structure–reactivity relationship

“…Some authors [48,49] reported similar peaks for palladium black catalysts used for the adsorption of ethene and acetylene at temperatures of 150ºC to 250ºC. Displacement of the Pd metal peaks to a lower scattering angle in used catalysts has also been observed in the hydrodechlorination of CCl2F2, CHClF2, and tetrachloroethene [28,50,51]. This shift has been attributed to the formation of palladium carbide (PdCx).…”

“…On the contrary, other authors observed re-dispersion of metal upon HDC, but when activated carbon was used as the support [20,28,33].…”

“…In gas-phase HDC, deactivation of noble metal catalysts has been linked to poisoning by HCl and/or Cl, formation of carbonaceous deposits, loss of metal through the formation of volatile chlorides, and metal sintering [8,16,23,[27][28][29][30][31]. However, most of these studies do not address the HDC of CMs and very few publications refer to activated carbon-supported noble metal catalysts.…”

“…The nature of the support has been reported to have a significant influence on poisoning by HCl [14,32]. Several authors have proposed the formation of carbonaceous deposits, including chlorine in their constitution in many cases, as one of the main causes of deactivation of these catalysts [16,23,28,33,34].…”

The efficient synthesis of carbon–carbon double bonds via Knoevenagel condensation using red mud packed in a column

“…RM is used for some chemical processes, such as producing hydrogen gas from coke (9), absorbing compounds such as arsenic (10), phosphate (11), nitrate (12), chromate (13), boron (14), fluoride (15), cadmium, lead, copper (16), phenol (17) and dye (18) from wastewater, as well as absorbing salt produced from sea water (19). Additionally, the catalytic activity of RM is known for the hydrogenation of organic compounds (20), and the hydrodechlorination of tetrachloroethylene (21). It has been found to degrade mixtures of municipal waste plastic, heavy vacuum gas oil and waste mineral oil to fuel oil (22).…”