Catalytic hydrodechlorination of chlorobenzene in liquide phase

Abstract

Abs~a~Catalytic hydrodeehlorination of chlorobenzene (CB) was carried out in the liquid phase in a mixture of methanol/water (MeOH/H20) at 30~ and 2 kg/cm 2 pressure. The reaction orders with respect to CB and 1-12 pressure were one and zero, respectively. Addition of NH4OH in the reaction produces a decrease in the activity (TOF). Solvent effect shows the following order of activity: H20 > MeOH/H20 > EtOH/H20 > MeOH.

Solvent effects in the catalytic hydrotreament of haloaromatics over Pd/Al2O3 in water+organic mixtures

“…The HDH rates in a representative mixture (85 %mol water) are given in Table 2, where higher (R HDH ) 0 values (by a factor of up to 5) were obtained in the solvent mixture relative to reaction in methanol. These results are in line with studies in the literature where enhanced HDH rates in methanol+ water mixtures with increasing water content have been noted (Benítez and del Angel, 1999;Concibido et al, 2006Concibido et al, , 2007b. This response has been attributed to a lesser catalyst deactivation as a result of increased solubility of HCl (Benítez and del Angel, 1999) and/or NaCl (formed during HCl neutralization with NaOH) (Concibido et al, 2006(Concibido et al, , 2007b, which facilitated their removal from the active surface.…”

“…These results are in line with studies in the literature where enhanced HDH rates in methanol+ water mixtures with increasing water content have been noted (Benítez and del Angel, 1999;Concibido et al, 2006Concibido et al, , 2007b. This response has been attributed to a lesser catalyst deactivation as a result of increased solubility of HCl (Benítez and del Angel, 1999) and/or NaCl (formed during HCl neutralization with NaOH) (Concibido et al, 2006(Concibido et al, , 2007b, which facilitated their removal from the active surface. In contrast, Concibido et al (2005) recorded a decrease in the HDH rate of tetrachloroethylene over Pd/C at higher water contents ( 450 %mol) due to an irreversible adsorption of the reactant on the carbon support.…”

Palladium supported on structured and nonstructured carbon: A consideration of Pd particle size and the nature of reactive hydrogen

“…Supported Pd catalysts are widely applied in hydrogen mediated catalysis, e.g., hydrogenation [1][2][3] and hydrogenolysis [4,5]. Pd catalysts have been established as effective in promoting hydrodehalogenation [4,[6][7][8][9][10][11][12][13][14] (hydrogenolytic C-X bond scission), which is used as a model reaction system in this study.…”

Hydrodehalogenation of haloarenes over Silica supported Pd and Ni

“…While high turnovers have been achieved, this approach is not suitable for environmental remediation purposes due to the involvement of additional chemicals and the associated product/solvent/catalyst separation steps. The heterogeneous catalytic hydrodechlorination of chlorobenzene and chlorophenol(s) as model reactants has been studied in both the gas [30][31][32][33][34][35][36][37][38][39][40][41] and liquid [42][43][44][45][46][47][48][49][50][51][52] phases, the latter involving the use of hydrogen donors as well as molecular hydrogen. The removal of multiple chlorine atoms from an aromatic host has been examined to a lesser extent [36,39,[53][54][55][56][57][58][59][60] while hydrodebromination reactions have received scant attention in the literature [61][62][63][64].…”