Chlorinated paraffins

Structure of 2,3,4,5,6,8-hexachlorodecane, an example of a short-chained chlorinated paraffin (61% Cl by weight)

Structure of 2,5,6,7,8,11,15-heptachloroheptadecane, an example of a medium-chain chlorinated paraffin (52% Cl by weight)

Chlorinated paraffins (CPs) are complex mixtures of certain organic compounds containing chloride: polychlorinated n-alkanes (see example structure to the right). The chlorination degree of CPs can vary between 30 and 70 wt%. CPs are subdivided according to their carbon chain length into short chain CPs (SCCPs, C_10–13), medium chain CPs (MCCPs, C_14–17) and long chain CPs (LCCPs, C_>17). Depending on chain length and chlorine content, CPs are colorless or yellowish liquids or solids.

CPs were introduced in the 1930s. Currently, over 200 CP formulations are in use for a wide range of industrial applications, such as flame retardants and plasticisers, as additives in metal working fluids, in sealants, paints and coatings and as a solvent for Dichloramine T (germicide).

SCCPs are classified as persistent and their physical properties (octanol-water partition coefficient logK_OW 4.4–8, depending on the chlorination degree) imply a high potential for bioaccumulation. Furthermore, CPs are classified as toxic to aquatic organisms, and carcinogenic to rats and mice. SCCPs were categorised in group 2B as possibly carcinogenic to humans from the International Agency for Research on Cancer (IARC). A global ban on SCCPs is being considered under the Stockholm Convention on Persistent Organic Pollutants.

Further reading

• Cherrie, J. W.; Semple, S. (2009). "Dermal Exposure to Metalworking Fluids and Medium-Chain Chlorinated Paraffin (MCCP)". Annals of Occupational Hygiene 54 (2): 228–35. doi:10.1093/annhyg/mep081. PMID 19959560. 
• Bayen, Stéphane; Obbard, Jeffrey Philip; Thomas, Gareth O. (2006). "Chlorinated paraffins: A review of analysis and environmental occurrence". Environment International 32 (7): 915–29. doi:10.1016/j.envint.2006.05.009. PMID 16814386. 
• Tolbert, Paige E. (1997). "Oils and Cancer". Cancer Causes & Control 8 (3): 386–405. doi:10.1023/A:1018409422050. JSTOR 3552699. PMID 9498901. 
• "Chlorinated paraffins" (PDF). IARC Monographs on the Evaluation of Carcinogenic Risks to Humans 48: 55–72. 1990. ISBN 978-92-832-1248-5. PMID 2197463. 
• Pellizzato, Francesca; Ricci, Marina; Held, Andrea; Emons, Hendrik (2007). "Analysis of short-chain chlorinated paraffins: A discussion paper". Journal of Environmental Monitoring 9 (9): 924–30. doi:10.1039/b710053a. PMID 17726552. 

External links

• Short Chain Chlorinated Paraffins - Proposal for identification of a substance as a CMR, PBT, vPvB or a substance of an equivalent level of concern