DaMocles WiSe 19/20: Mirex Group: 04

Marius Wollrab Milan Zengeler Maurice Wingsheim

February 2, 2020 Contents

1. General information 1

2. Synthesis 2

3. Toxicology 2

4. Ban 3

II. References I

I 1. General information

Mirex, Dechlorane or Perchloropentacyclodecane (figure 1) is a synthetic produced, white, odorless, crystalline solid chlorinated hydrocarbon. The IUPAC name is: 1,1a,2,2,3,3a,4,5,5,5a,5b,6- dodecachlorooctahydro-1H-1,3,4-(methanetriyl)cyclobuta[cd]pentalene and the GHS classification is depicted in figure 2.

Figure 1: Structure of Mirex [1]

Figure 2: GHS Classification [2]

1 Chemical and physical properties:

Property name Property value 1 Molecular weight 545,5 g mol− 1 Exact mass 545,617 382 g mol−

Melting point 485 ◦C

Chemical formula C10Cl12 CAS-Nr. 2385-85-5

Mirex was commonly used as a stomach insecticide against imported fire ants Solenopsis saevissima richteri and as a fire-retardant for plastics, paper, electronics and paint. As a fire-retardant, Mirex was sold underthe name of Dechlorane. The top producer of Mirex was the USA and up to 75% were exported to country’s in south and middle America.[2]

2. Synthesis

Mirex can be synthesized by dimerization of hexachlorocyclopentadiene (figure 3). For this reaction aluminiumchloride is used as catalyst.

Figure 3: Synthesis of Mirex

3. Toxicology

Mirex targets and damages the liver, kidney, eye, thyroid, central nervous system and the reproductive organs. Studies on laboratory animals have caused it to be classified as a possible human carcinogen.[3]

2 Mirex is also dangerous for humans and the environment, because of the risk of bioaccumulation. Bioaccumulation occurs because Mirex is very resistant to microbiological degradation and also not soluable in water but in nonpolar solvents. Part of the resistance against metabolism is, that there are not many microbes capable of removing halogen atoms, therefore, Mirex will accumulate in the environment. Only anaerobic microbes in sewage slug have shown a slow dechlorination to a monohydro derivative. There are no reports of soil microorganisms that can degrade Mirex. [4, 5]

An example for this problem is Lake Ontario. [6] Here, Mirex is found at the bottom of the Lake, where it’s ingested by fish. Mirex then accumulates in the fat cells. The accumulated toxins are traveling throughthe food-chain, up to humans. Tissue with a lot of fat (e.g Liver) is at high risk of accumulation and damage through Mirex.

4. Ban

In 1984, the International Programme on Chemical Safety (IPCS) published a report about the impact on the environment. The conclusion of this report states the following:

“1. No data on human health effects are available in connection with occupational exposure to mirex. Based on the findings in mice and rats, this chemical should be considered, for practical purposes, asbeing potentially carcinogenic for human beings.

2. For the same reason, reservations must remain about the safety of this chemical in food, despite the relatively low residues so far reported.

3. Effects on the organisms studied, as well as its persistence, suggest that mirex presents a long-term hazard for the environment.

4. Taking into account these considerations, it is felt that the use of this chemical for both agricultural and non-agricultural applications should be discouraged, except where there is no adequate alternative.”[5]

Therefore, on the 22th May of 2001, the Stockholm Convention on Persistent Organic Pollutants declared Mirex as part of "The 12 Initial POPs" as banned (Persistent Organic Pollutants). The Convention prohibits the import, export and the use of Mirex. [7]

3 II. References

[1] NEUROtiker, Struktur von Mirex, 28. July 2008, https://de.wikipedia.org/wiki/Mirex# /media/Datei:Mirex.svg.

[2] PubChem Database: Mirex, National Center for Biotechnology Information, https://pubchem.ncbi.nlm.nih.gov/compound/Mirex (visited on Jan. 29, 2020).

[3] Secretariat of the Stockholm Convention, Listing of POPs in the Stockholm Convention, 22. May 2001, http://chm.pops.int/TheConvention/ThePOPs/The12InitialPOPs/tabid/296/ Default.aspx (visited on Jan. 30, 2020).

[4] E. Croom in Toxicology and Human Environments, (Ed.: E. Hodgson), Progress in Molecular Biology and Translational Science, Academic Press, 2012, pp. 31–88, http://www.sciencedirect.com/ science/article/pii/B9780124158139000039.

[5] International Programme on Chemical Safety (IPCS), Environmental Health Criteria 44: Mirex (EHC 44, 1984), 1984, http://www.inchem.org/documents/ehc/ehc/ehc44.htm#SectionNumber: 3.1 (visited on Feb. 1, 2020).

[6] R. Scrudato, A. DelPrete, “Lake Ontario Sediment - Mirex Relationships”, Journal of Great Lakes Research 1982, http://www.sciencedirect.com/science/article/pii/S038013308272009X.

[7] Secretariat of the Stockholm Convention, Overview, 22. May 2001, http://chm.pops.int/TheConvention/Overview/tabid/3351/Default.aspx (visited on Jan. 31, 2020).

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