Catalytic hydrodechlorination of dioxins over palladium nanoparticles in supercritical CO2 swollen microcellular polymers.
In this study, palladium nanoparticles embedded in monolithic microcellular high density polyethylene supports are synthesized as heterogeneous catalysts for remediation of 1,6-dichlorodibenzo-p-dioxin and 2,8-dichlorodibenzofuran in 200 atm of supercritical carbon dioxide containing 10 atm of hydrogen gas and at 50-90°C. Stepwise removal of chlorine atoms takes place first, followed by saturation of two benzene rings with slower reaction rates. The pseudo first order rate constant of initial hydrodechlorination for 2,8-dichlorodibenzofuran is 4.3 times greater than that for 1,6-dichlorodibenzo-p-dioxin at 78°C. The catalysts are easily separated from products and can be recyclable and reusable without complicated recovery and cleaning procedures.
Department of Chemistry, National Dong Hwa University, Hua-Lien 970, Taiwan, ROC.
Ben-Zen
BZ
Wu
Hsiang-Yu
HY
Chen
Joanna S
JS
Wang
Chung-Sung
CS
Tan
Chien M
CM
Wai
Weisheng
W
Liao
KongHwa
K
Chiu
D001572:Benzofurans / Q000737:chemistry*; D002245:Carbon Dioxide / Q000737:chemistry; D002384:Catalysis; D002713:Chlorine / Q000737:chemistry*; D000072338:Dibenzofurans, Polychlorinated; D004785:Environmental Pollutants / Q000737:chemistry; D053768:Metal Nanoparticles / Q000737:chemistry*; D010165:Palladium / Q000737:chemistry*; D000072317:Polychlorinated Dibenzodioxins / Q000031:analogs & derivatives* / Q000737:chemistry; D020959:Polyethylene / Q000737:chemistry
D001572:Benzofurans; D000072338:Dibenzofurans, Polychlorinated; D004785:Environmental Pollutants; D000072317:Polychlorinated Dibenzodioxins; D002245:Carbon Dioxide; D002713:Chlorine; D010165:Palladium; D020959:Polyethylene