Title: De novo synthesis of dioxins: a review
Authors: Mengmei Zhang; Alfons Buekens
Addresses: State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou, China ' State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou, China
Abstract: Laboratory studies are reviewed on the de novo synthesis of polychlorinated dibenzo-p-dioxins (PCDD) and polychlorinated dibenzofurans (PCDF), in brief dioxins (PCDD/F). This synthesis starts from carbon, contained in either real or model incinerator fly-ash. It is influenced by reaction temperature and time, carbon, chlorides and catalyst in fly-ash and the composition of the gas phase. De novo tests look deceivingly simple, starting from the experimental set-up, procedures and results, yet there is wide-ranging variance in experimental results. The accompanying theories and explanations show profound divergence and dilemmas, the potential reasons of which are examined. The evident link with other chloro-aromatic classes, such as chlorophenols (CP), chlorobenzenes (CBz), polychlorinated biphenyls (PCB) and with polycyclic aromatic hydrocarbons (PAH) is also considered. Precursor routes and suppression are not treated. A second paper revisits the iron ore sintering data of European Union research project 'Minimisation of dioxins in thermal industrial processes: mechanisms, monitoring and abatement (MINIDIP)', as a concrete case-study illustrating this review.
Keywords: de novo synthesis; dioxins; review; catalysis; precursors; surrogates; chloroaromatics; model fly ash; MFA; PCDD/F; reaction temperature; reaction time; carbon; chlorides; catalysts; gas phase; chlorophenols; chlorobenzenes; polychlorinated biphenyls; PCB; polycyclic aromatic hydrocarbons; PAH.
International Journal of Environment and Pollution, 2016 Vol.60 No.1/2/3/4, pp.63 - 110
Received: 21 May 2016
Accepted: 19 Aug 2016
Published online: 07 Feb 2017 *