39001-02-0Relevant articles and documents
Effects of oxygen on formation of PCB and PCDD/F on extracted fly ash in the presence of carbon and cupric salt
Pekarek,Grabic,Marklund,Puncochar,Ullrich
, p. 777 - 782 (2007/10/03)
The effect of oxygen-nitrogen atmosphere (N2 + 10%O2, N2 + 1%O2 and 99.999% N2) on the formation of PCB, PCDD and PCDF by the de novo synthetic reactions in the system consisting of extracted fly ash
Mechanistic studies on the role of PAHs and related compounds in PCDD/F formation on model fly ashes
Wilhelm,Stieglitz,Dinjus,Will
, p. 797 - 802 (2007/10/03)
Model fly ashes containing Florisil , CuCl2 · 2H2O and PAHs with structures similar to dibenzo-p-dioxin or dibenzofuran were heated at 250°C in He/O2 with regard to a supposed intramolecular reaction mechanism for oxygen incorporation. Highest reactivities in PCDF formation could be found for model compounds containing a biphenyl structure, while condensed π-systems lead to a decrease in reactivity for such compounds. Biphenyl is almost completely converted to dibenzofuran. PCDD formation from six-membered rings like xanthene/9,10-dihydroanthracene is of minor importance. 18O-labeling of gaseous oxygen reveals no common reaction step for oxygen incorporation using 9-fluorenone, xanthene, diphenyl ether and diphenyl-2-carboxylic acid as model compounds. Pre-existing oxygen in reactants is a major source for ether groups in PCDD and PCDF. Determination of labeled and unlabeled CO and CO2 besides He/O2 reflects higher reactivities towards oxidation for model compounds containing ether groups than for compounds with carbonyl groups.
Copper-catalyzed chlorination and condensation of acetylene and dichloroacetylene
Taylor, Philip H.,Wehrmeier, Andreas,Sidhu, Sukh S.,Lenoir, Dieter,Schramm,Kettrup
, p. 1297 - 1303 (2007/10/03)
The chlorination and condensation of acetylene at low temperatures is demonstrated using copper chlorides as chlorinated agents coated to model borosilicate surfaces. Experiments with and without both a chlorine source and borosilicate surfaces indicate the absence of gas-phase and gas-surface reactions. Chlorination and condensation occur only in the presence of the copper catalyst. C2 through C8 organic products were observed in the effluent; PCDD/F were only observed from extraction of the borosilicate surfaces. A global reaction model is proposed that is consistent with the observed product distributions. Similar experiments with dichloroacetylene indicate greater reactivity in the absence of the copper catalyst. Reaction is observed in the gas-phase and in the presence of borosilicate surfaces at low temperatures. The formation of hexachlorobenzene is only observed in the presence of a copper catalyst. PCDD/F were only observed from extraction of the borosilicate surfaces. A global reaction model is proposed for the formation of hexachlorobenzene from dichloroacetylene. (C) 2000 Elsevier Science Ltd.
