Formation of polychlorinated diphenyl ethers from condensation of chlorophenols with chlorobenzenes

Mechanism of polychlorinated diphenyl ether formation on a simulated fly ash surface

“…Therefore, the condensation of PCP with 1,2,4,5-Cl 4 Bz to form OCDE was the predominant reaction in the system, while the condensation of two PCP molecules to form DecaCDE was a lesser reaction on the SiO 2 surface. This result was consistent with the findings of Liu et al [34], who described the formation mechanism of PCDEs in homogeneous gas phase reactions. Therefore, the presence of SiO 2 does not change the reaction processes of PCP and 1,2,4,5-Cl 4 Bz.…”

“…The content of 2,2 ,3,4,4 ,5,5 ,6-OCDE was consistently higher than that of DecaCDE. Two isomers of HpCDE were formed on the surface of SiO 2 under nitrogen, which was inconsistent with the results from the condensation of PCP with 1,2,4,5-Cl 4 Bz in the gas phase [34]. It can be concluded that the dechlorination reaction occurs more easily on the surface of SiO 2 without oxygen than in the homogeneous gas reaction.…”

“…The occurrence and distribution of PCDEs have been investigated systematically from gas phase reactions of chlorophenols and chlorobenzenes in a sealed glass tube [34]. This research illustrated a formation pathway for PCDEs in a homogeneous reaction.…”

Influence of iron and copper oxides on polychlorinated diphenyl ether formation in heterogeneous reactions

“…Therefore, the condensation of PCP with 1,2,4,5-Cl 4 Bz to form OCDE was the predominant reaction in the system, while the condensation of two PCP molecules to form DecaCDE occurred less on the SiO 2 /Fe 2 O 3 surface, which was consistent with the results from the condensation of PCP with 1,2,4,5-Cl 4 Bz on the surface of SiO 2 (Liu et al 2011). This result was also consistent with the findings of Liu et al (2008), who described the formation mechanism of PCDEs in homogeneous gas phase reactions. The presence of Fe 2 O 3 does not change the reaction processes of PCP and 1,2,4,5-Cl 4 Bz.…”

Modeling the overall persistence and environmental mobility of sulfur-containing polychlorinated organic compounds

“…1), have been identified in various environmental samples: bleached pulp mill effluents, stack gas samples, fly ashes, pine needles, soil, sediments, tissues of aquatic biota (Sielex and Andersson 1997;Sinkkonen 1997;Sinkkonen et al 1995a, b;Cai et al 1994). PASHs are synthesized in a sulfurized coal combustion in the presence of chlorine, or reactions of polychlorinated molecules with sulfur under certain conditions (Liu et al 2008;Grzybek et al 2002;Lindahl and Rappe 1980). The presence of PASHs in wastewater effluents may result in emissions into the atmosphere and, consequently, in acid rains and/or acceleration of steel corrosion processes, as they are similar to such volatile sulfur compounds (VSCs) as thiophene or Fig.…”