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Dibenzo-1,4-dioxin, also dibenzodioxin or dibenzo-p-dioxin (dibenzo-para-dioxin), is a polycyclic heterocyclic organic compound in which two benzene rings are connected by a 1,4-dioxin ring. Its molecular formula is C 12 H 8 O 2. The two oxygen atoms occupy opposite (para-) positions in the six-membered dioxin ring.
Polychlorinated dibenzodioxins (PCDDs), or simply dioxins, are a group of long-lived polyhalogenated organic compounds that are primarily anthropogenic, and contribute toxic, persistent organic pollution in the environment.
Dibenzo-1,4-dioxin, also known as dibenzodioxin or dibenzo-p-dioxin (molecular formula C 12 H 8 O 2), in which two benzene rings are connected through two oxygen atoms. That is the parent compound of the dioxins (see next in which the dioxins comprise a key part of the class).
TCDD and dioxin-like compounds act via a specific receptor present in all cells: the aryl hydrocarbon (AH) receptor. [6] [7] [8] This receptor is a transcription factor which is involved in the expression of genes; it has been shown that high doses of TCDD either increase or decrease the expression of several hundred genes in rats. [9]
1,4-Dioxin (also referred as dioxin or p-dioxin) is a heterocyclic, organic, non-aromatic [2] compound with the chemical formula C 4 H 4 O 2. There is an isomeric form of 1,4-dioxin, 1,2-dioxin (or o -dioxin). 1,2-Dioxin is very unstable due to its peroxide -like characteristics.
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The rate constant for the vapor phase reaction of heptachlorodibenzo-p-dioxin with photochemically produced hydroxyl radicals has been estimated to be 1.3x10 −12 cu cm/molecule-sec at 25 °C which corresponds to an atmospheric half-life of 12.3 days at an atmospheric concentration of 5x10 5 hydroxyl radicals per cu cm. [13]
[1] It is one of the dominant dioxin congeners in smoke emissions, but because it is much less soluble than e.g. TCDD, it is not bioaccumulated as effectively and it is toxicologically less important than the most prevalent dioxins.