Hydrogenolysis of chlorobenzene, dichlorobenzenes and chlorotoluenes by in situ generated and gaseous hydrogen in alkaline media and the presence of Pd/C catalyst

Catalytic hyrodechlorination of chlorophenols in aqueous solution under mild conditions

“…A variety of hydrogen donors have been used, including inorganic salts (borohydrides [22][23][24], phosphinates [25]) organic salts (formic acid and its salts [26][27][28], hydrazine·HCl [29,30]), alcohols (butan-2-ol [31], propan-2-ol [32,33]), or proaromatic compounds. Alternatively, CO [34,35] (water-gas shift reaction), zero-valent metal [36][37][38][39] and bimetallic mixtures [40,41] can mediate H 2 O hydrolytic reduction.…”

Kinetics of 10% Pd/C-catalysed hydrogenolysis of chlorobenzene dissolved in n-heptane by gaseous hydrogen in contact with aqueous NaOH or water

“…Hydrodehalogenation of these compounds has been carried out in gaseous [17][18][19][20][21][22][23] and liquid [24][25][26][27][28][29][30][31][32][33][34][35][36][37] phases. A variety of hydrogen reactants have been used -gaseous hydrogen [26][27][28][29][30][31][34][35][36][37] or other substances readily releasing it [24,25,33]. It has been noted that the catalyst surface deactivates during hydrogenolysis in both liquid and gaseous phases [2,[13][14][15]17,[21][22][23]31].…”

“…A variety of hydrogen reactants have been used -gaseous hydrogen [26][27][28][29][30][31][34][35][36][37] or other substances readily releasing it [24,25,33]. It has been noted that the catalyst surface deactivates during hydrogenolysis in both liquid and gaseous phases [2,[13][14][15]17,[21][22][23]31]. Two factors have been recognised as causing this deactivation: adsorption of the hydrogen halide on the catalyst's active sites [2,[13][14][15]17,31] and deposition of carbonaceous species [21,23].…”

“…It has been noted that the catalyst surface deactivates during hydrogenolysis in both liquid and gaseous phases [2,[13][14][15]17,[21][22][23]31]. Two factors have been recognised as causing this deactivation: adsorption of the hydrogen halide on the catalyst's active sites [2,[13][14][15]17,31] and deposition of carbonaceous species [21,23]. The latter process takes place when dehalogenation is carried out at elevated temperatures in the gaseous phase.…”

“…During liquid catalytic hydrodehalogenation, in the presence of different bases binding the released hydrohalides, deposition of carbonaceous species does not occur as far as we know. A single solvent for a base and the organochlorine compounds [24][25][26][27][28][29]32], or multiphase systems composed of organic solvent and an aqueous solution of a base [31,[33][34][35][36][37] have been used in the presence of different noble metal catalysts and hydrogen reactants. Multiphase media consisting of an organic layer containing an organochlorine compound, an aqueous solution of a base, and palladium supported on an activated carbon, have been found optimal for carrying out hydrodechlorination [33][34][35][36][37].…”