1,4-Dioxin

Source: Wikipedia, the free encyclopedia.
Not to be confused with 1,4-Dioxane.
For other dioxin compounds, see dioxin.
1,4-Dioxin
Names
Preferred IUPAC name
1,4-Dioxine[1]
Systematic IUPAC name
1,4-Dioxacyclohexa-2,5-diene
Other names
1,4-Dioxin
Dioxin
p-Dioxin
1,4-Dioxa[6]annulene
Identifiers
3D model (
JSmol
)
ChEBI
ChemSpider
UNII
  • InChI=1S/C4H4O2/c1-2-6-4-3-5-1/h1-4H checkY
    Key: KVGZZAHHUNAVKZ-UHFFFAOYSA-N checkY
  • InChI=1/C4H4O2/c1-2-6-4-3-5-1/h1-4H
    Key: KVGZZAHHUNAVKZ-UHFFFAOYAD
  • O\1/C=C\O/C=C/1
Properties
C4H4O2
Molar mass 84.07 g/mol
Appearance Colorless liquid
Boiling point 75 °C (167 °F; 348 K)
Hazards
Occupational safety and health (OHS/OSH):
Main hazards
 highly flammable
Related compounds
Related compounds
dibenzodioxin

dithiin

Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
☒N verify (what is checkY☒N ?)

1,4-Dioxin (also referred as dioxin or p-dioxin) is a heterocyclic, organic, non-aromatic[2] compound with the chemical formula C4H4O2. 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.

The term "dioxin" is most commonly used for a family of derivatives of dioxin, known as polychlorinated dibenzodioxins (PCDDs).

Preparation

1,4-Dioxin can be prepared by cycloaddition, namely by the Diels–Alder reaction of furan and maleic anhydride. The adduct formed has a carbon-carbon double bond, which is converted to an epoxide. The epoxide then undergoes a retro-Diels–Alder reaction, forming 1,4-dioxin and regenerating maleic anhydride.[3]

Scheme describing the 1994 synthesis of 1,4-dioxin

Derivatives

Figure 1: The skeletal formula and substituent numbering scheme of dibenzo-1,4-dioxin, the parent compound of PCDDs

The word "dioxin" can refer in a general way to compounds which have a dioxin core skeletal structure with substituent molecular groups attached to it. For example, dibenzo-1,4-dioxin is a compound whose structure consists of two benzo- groups fused onto a 1,4-dioxin ring.

Polychlorinated dibenzodioxins

Main article: polychlorinated dibenzodioxins

Because of their extreme importance as environmental pollutants, current scientific literature uses the name dioxins commonly for simplification to denote the chlorinated derivatives of dibenzo-1,4-dioxin, more precisely the

carcinogens
.

PCDDs are formed through combustion, chlorine bleaching and manufacturing processes.[4] The combination of heat and chlorine creates dioxin.[4] Since chlorine is often a part of the Earth's environment, natural ecological activity such as volcanic activity and forest fires can lead to the formation of PCDDs.[4] Nevertheless, PCDDs are mostly produced by human activity.[4]

Famous PCDD exposure cases include

U.S. military in Vietnam during the Vietnam War, the Seveso disaster, and the poisoning of Viktor Yushchenko
.

Polychlorinated dibenzofurans are a related class compounds to PCDDs which are often included within the general term "dioxins".

References

  1. ISBN 978-0-85404-182-4
    .
  2. ^ Science of Synthesis: Houben-Weyl Methods of Molecular Transformations Vol. 16: Six-Membered Hetarenes with Two Identical Heteroatoms
  3. doi:10.1039/p19940000927
    .
  4. ^ a b c d "Dioxin Information". Department of Environmental Protection, State of Maine. 2005. Archived from the original on 2009-06-15. Retrieved 2008-08-10.
Retrieved from "https://en.wikipedia.org/w/index.php?title=1,4-Dioxin&oldid=1147831554"