The Pd-catalyzed hydrodechlorination of chlorophenols in aqueous solutions under mild conditions: a promising approach to practical use in wastewater.
Catalytic hydrotreating of chlorophenols was carried out in water with Pd/C at 25 degrees C under atmospheric pressure. 1.0% (w/w) monocholophenols was completely dechlorinated within 60 min. Phenol, cyclohexanone and cyclohexanol were formed. In contrast to the dechlorination of monochlorophenols, the hydrogenation reaction of polychlorinated phenols became difficult and reaction rates were strongly dependent upon the number of the chlorine atoms. The solvent property had a considerably important influence on the dechlorination reaction. Water as a solvent showed more advantages than organic solvents. It was much easier to be hydrodechlorinated for chlorophenols in aqueous solutions. However, the presence of THF, dioxane, DMSO or DMF in water was disadvantageous to the reaction and easily to cause Pd/C deactivation. Additionally, when different halogenated organic compounds were present in aqueous solution, the dehalogenation reaction was the competitive hydrogenation process.
Xia
Chuanhai
C
Yantai Institute of Coastal Zone Research for Sustainable Development, CAS, Yantai 264003, China. chuanhaixia@gmail.com
Liu
Ying
Y
Zhou
Shiwei
S
Yang
Cuiyun
C
Liu
Sujing
S
Xu
Jie
J
Yu
Junbao
J
Chen
Jiping
J
Liang
Xinmiao
X
D002384:Catalysis; D055598:Chemical Phenomena; D002713:Chlorine / Q000737:chemistry*; D002733:Chlorophenols / Q000737:chemistry*; D003511:Cyclohexanols; D003512:Cyclohexanones; D006865:Hydrogenation; D010165:Palladium; D019800:Phenol; D012996:Solutions; D014865:Waste Disposal, Fluid / Q000379:methods*
D002733:Chlorophenols; D003511:Cyclohexanols; D003512:Cyclohexanones; D012996:Solutions; D019800:Phenol; D002713:Chlorine; C036468:cyclohexanone; D010165:Palladium