Chlorinated paraffins

safety instructions
Surname	short-chain chlorinated paraffins C 10 -C 13 chloroparaffins C 10 -C 13 chloroalkanes SCCP
CAS number	85535-84-8
EC number	287-476-5
ECHA InfoCard	100,079,496
GHS hazard labeling from  Regulation (EC) No. 1272/2008 (CLP) , expanded if necessary Caution H and P phrases H: 351-410 EUH: 066 P: 281-273-308 + 313
Authorization procedure under REACH	of particular concern : persistent, bioaccumulative and toxic ( PBT ), very persistent and very bioaccumulative ( vPvB )

safety instructions
Surname	medium-chain chlorinated paraffins C 14 -C 17 chloroparaffins C 14 -C 17 chloroalkanes MCCP
CAS number	85535-85-9
EC number	287-477-0
ECHA InfoCard	100,079,497
GHS hazard labeling from  Regulation (EC) No. 1272/2008 (CLP) , expanded if necessary Caution H and P phrases H: 362-410 EUH: 066 P: ?

safety instructions
Surname	long-chain chlorinated paraffins C 18 -C 28 chloroparaffins C 18 -C 28 chloroalkanes LCCP
CAS number	85535-86-0
EC number	287-478-6
ECHA InfoCard	100,079,498
GHS labeling of hazardous substances no GHS pictograms H and P phrases H: 413 P: ?

Chlorinated paraffins ( CP ) are mixtures of substances made from polychlorinated, saturated, unbranched hydrocarbons with 10–30 carbon atoms, which correspond to the general formula C _x H _{(2 x - y +2)} Cl _y . They are produced by the chlorination of n -alkanes , which results in complex mixtures of different chloroalkanes . The degree of chlorination varies between 30 and 70 percent by mass .

production

Chlorinated paraffins are produced industrially by reacting chlorine with unbranched paraffin fractions (<2% isoparaffins, <100 ppm aromatics ) at temperatures of 80–100 ° C. The radical substitution can also be initiated by UV light ( photochlorination ).

C _x H _{(2 x +2)} + y Cl ₂ → C _x H _{(2 x - y +2)} Cl _y + y HCl

When the desired degree of chlorination has been reached, the reaction product is freed from residual chlorine and hydrogen chloride by purging with nitrogen and then stabilized by adding epoxidized vegetable oil .

Chlorinated paraffins are produced in Europe, North America, Asia, Australia, Brazil and South Africa. The main production country of CP is China, where around 600,000 tons were produced in 2007. The amount produced annually worldwide is more than one million tons. It has been estimated that at least 165,000 tons of this are short-chain chlorinated paraffins.

Classification

The products on the market are highly complex mixtures of polychlorinated n -alkanes that can contain thousands of homologues and isomers . With the standard methods of chemical analysis it is currently not possible to completely separate these mixtures and to identify all the compounds contained.

Due to their chain length, CP are divided into short-chain CP ( SCCP , short chain CPs , C _10–13 ), medium-chain CP ( MCCP , medium chain CPs , C _14–17 ) and long-chain CP ( LCCP , long chain CPs C _{> 17} ). Depending on the chain length and chlorine content, chlorinated paraffins are colorless or yellowish, easily mobile to highly viscous liquids or glassy solidified to waxy solids. They are chemical and light resistant, temperature resistant up to approx. 200 ° C, comparatively little volatile and flame retardant.

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  Structure of 2,3,4,5,6,8-hexachlorodecane as an example of a short-chain chlorinated paraffin with a chlorine content of 61 mass percent

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  Structure of 2,5,6,7,8,11,15-heptachlorheptadecane as an example of a medium-chain chlorinated paraffin with a chlorine content of 52 mass percent

use

Chlorinated paraffins are mainly used as plasticizers in plastics and coatings, as binders in paints, as an additive in joint sealing compounds, in metal processing , in fatliquors for leather and fur products and as flame retardants in plastics, rubber, paper and textiles.

The flame-retardant effect of CP is due to the elimination of incombustible hydrogen chloride at high temperatures. In addition, chain termination reactions disrupt the combustion process and flame spread. Partly because of their applications, CP have taken the place of polychlorinated biphenyls (PCBs), which are now banned because of their toxicity.

The annual emissions of SCCP from the city of Zurich were determined to be 218–321 kg, which corresponds to an amount of 1.5–2.2 mg per person and day.

properties

Due to their physico-chemical and ecotoxicological properties, short-chain CP are environmentally hazardous substances with high persistence and high bioaccumulation potential (accumulation in adipose tissue, in the kidneys and in the liver). They are also very toxic to aquatic organisms and carcinogenic to rats and mice. Short-chain CP have also been classified by the IARC in Group 2B, as a possible carcinogen for humans. The acute toxicity of chlorinated paraffins is low. Chronic toxicity increases with decreasing carbon chain length.

CP are ubiquitous , i.e. This means that they can be detected all over the world in soils, bodies of water, sediments , plants, animals, people, etc. The MCCP concentrations in soils, biota and in most sediment cores have shown an increasing trend in the last few years to decades.

Chlorinated paraffins can be converted into chlorinated olefins by HCl elimination when exposed to thermal stress, for example in metalworking .

Bans on short-chain chlorinated paraffins

In the EU, the member states were obliged in 2002 to prohibit the placing on the market of short-chain CP in substances and preparations with a concentration of more than 1% for use in greasing leather or in metal processing by January 5, 2004 at the latest; further restrictions should be checked. In 2017, short-chain chlorinated paraffins were included in Appendix A of the Stockholm Convention .

With Regulation (EU) No. 519/2012 of June 19, 2012 amending Regulation (EC) No. 850/2004 of the European Parliament and of the Council on persistent organic pollutants (known as POP-VO; replaced by Regulation (EU ) 2019/1021 ) production, use and placing on the market were prohibited in the EU, provided that SCCPs are not contained in less than 1% by weight in substances and preparations or not just as unintentional trace contamination in articles. Corresponding prohibitions apply in Switzerland. From December 2015, the limit value in articles in the EU was set at 0.15% by weight. In Switzerland, this lower limit came into force on July 1, 2018. In Germany, a violation of these prohibitions is a criminal offense even in the case of negligence.

Analytics

The chemical analysis of chlorinated paraffins is very demanding, as it involves highly complex mixtures of paraffins with different chain lengths, degrees of chlorination, substitution patterns ( constitutional isomers ) and spatial arrangement ( configuration isomers ), i.e. thousands of individual compounds. The accurate quantification of chlorinated paraffins in a sample is therefore one of the greatest challenges in chemical environmental analysis today. The difficulties are based on three aspects:

1. A chromatographic separation only works to a limited extent, as the thousands of individual compounds sometimes differ only slightly in terms of their physical-chemical properties and therefore strongly overlap in the chromatogram of a chlorinated paraffin mixture.
2. The complex chloroparaffin mixtures contain numerous compounds - including chlorolefins formed by HCl elimination - whose masses differ only slightly and where separation by mass spectrometry is correspondingly difficult. In the case of some mass interferences, the separation is achieved by means of high-resolution mass spectrometry. However, there are also cases in which even the most modern devices are not sufficient.
3. The quantification based on calibration using a standard series is not easily possible with chlorinated paraffins. Since the device sensitivity depends strongly on the degree of chlorination of the sample, the selection of a standard with a similar degree of chlorination is decisive for correct quantification.

Depending on the question, different methods are recommended. For example, only a method based on chemical ionization at atmospheric pressure and high-resolution time -of- flight mass spectrometry is suitable for quantifying the sum of long-chain chlorinated paraffins . The quantification takes place via an external calibration with several standard mixtures after deconvolution of the mass spectra.

literature

• Roman Bolliger, Anke Randegger-Vollrath: Short-chain chlorinated paraffins: material flow analysis. (= Environment series. 354). Swiss Federal Office for the Environment, Forests and Landscape , Bern 2003.
• European Chemicals Bureau: European Union Risk assessment report Vol. 4: Alkanes, C10-13, chloro. Office for Official Publications of the European Community, Luxembourg 2000.
• European Chemicals Bureau: European Union Risk assessment report Vol. 81: Alkanes, C10-13, chloro (update). Office for Official Publications of the European Community, Luxembourg 2008.
• European Chemicals Bureau: European Union Risk assessment report Vol. 58: Alkanes, C14-17, chloro (MCCP), Part I-Environment. Office for Official Publications of the European Community, Luxembourg 2005.
• European Commission: European Union Risk assessment report: Alkanes, C14-17, chloro; Addendum to the final report (2007) of the risk assessment - Environment part. Office for Official Publications of the European Community, Luxembourg 2011.
• European Commission: European Union Risk assessment report: Alkanes, C14-17, chloro (MCCP), Part II-Human Health. Office for Official Publications of the European Community, Luxembourg 2011.
• Gesellschaft Deutscher Chemiker, advisory committee for environmentally relevant existing substances: Chlorinated paraffins: (paraffin waxes and hydrocarbon waxes, chlorinated). VCH, Weinheim 1993, ISBN 3-527-28602-0 .

Individual evidence

1. ↑ ^{a b} Entry on chloroalkanes, C10-C13 in the GESTIS substance database of the IFA , accessed on August 27, 2016(JavaScript required) .
2. ↑ Entry on Alkanes, C10-13, chloro in the Classification and Labeling Inventory of the European Chemicals Agency (ECHA), accessed on August 1, 2016. Manufacturers or distributors can expand the harmonized classification and labeling .
3. ↑ Entry in the SVHC list of the European Chemicals Agency , accessed on September 25, 2014.
4. ↑ Entry on chloroalkanes (C14-17) in the GESTIS substance database of the IFA , accessed on August 27, 2016(JavaScript required) .
5. ↑ Entry on Alkanes, C14-17, chloro in the Classification and Labeling Inventory of the European Chemicals Agency (ECHA), accessed on August 1, 2016. Manufacturers or distributors can expand the harmonized classification and labeling .
6. ↑ There is not yet a harmonized classification for this substance . A labeling of Alkanes, C18-28, chloro in the Classification and Labeling Inventory of the European Chemicals Agency (ECHA), accessed on June 12, 2018 , is reproduced from a self-classification by the distributor .
7. ↑ Kerstin Kenne, Ulf G Ahlborg: Chlorinated paraffins. IPCS, Environmental Health Criteria 181. World Health Organization, Geneva 1996, ISBN 92-4157181-0 .
8. ^ DM Brooke, MJ Crookes, MD Merckel: Environmental risk assessment: long-chain chlorinated paraffins . Environment Agency, Bristol, UK 2009, ISBN 978-1-84432-977-9 , pp. 3-4, 23.
9. ↑ Thomas Kellersohn: Chlorinated paraffins. In: Ullmann's encyclopedia of industrial chemistry. electronic release, 6th edition. Wiley-VCH, Weinheim 1998.
10. ^ Carsten Lassen et al .: Survey of short-chain and medium-chain paraffins. Danish Ministry of Environment, Environmental Protection Agency, Copenhagen 2014, pp. 50–51.
11. ^ J. De Boer, Ali T. El-Sayed, H. Fiedler, J. Legler, DC Muir, VA Nikiforov, GT Tomy, K. Tsunemi: Chlorinated Paraffins. In: The Handbook of Environmental Chemistry. Springer-Verlag, Berlin 2010, ISBN 978-3-642-10760-3 , p. 8.
12. ↑ Juliane Glüge, Zhanyun Wang, Christian Bogdal, Martin Scheringer , Konrad Hungerbühler : Global production, use, and emission volumes of short-chain chlorinated paraffins - A minimum scenario. In: Science of The Total Environment . 573, 2016, pp. 1132–1146, doi: 10.1016 / j.scitotenv.2016.08.105 .
13. ^ ^{A b} Gregg T. Tomy, Gary A. Stern, Derek CG Muir, Aaron T. Fisk, Chris D. Cymbalisty, John B. Westmore: Quantifying C ₁₀ −C ₁₃ Polychloroalkanes in Environmental Samples by High-Resolution Gas Chromatography / Electron Capture Negative Ion High-Resolution Mass Spectrometry. In: Analytical Chemistry . 69, 1997, pp. 2762-2765, doi: 10.1021 / ac961244y .
14. ^ Carsten Lassen et al .: Survey of short-chain and medium-chain paraffins. Danish Ministry of Environment, Environmental Protection Agency, Copenhagen 2014, p. 30.
15. ^ Pascal S. Diefenbacher, Christian Bogdal, Andreas C. Gerecke, Juliane Glüge, Peter Schmid, Martin Scheringer , Konrad Hungerbühler : Short-Chain Chlorinated Paraffins in Zurich, Switzerland — Atmospheric Concentrations and Emissions . In: Environmental Science & Technology . tape 49 , no. 16 , August 7, 2015, p. 9778-9786 , doi : 10.1021 / acs.est.5b02153 .
16. ^ IARC. 1990. International Agency for Research on Cancer. Monographs on the Evaluation of Carcinogenic Risks to Humans. Volume 48 . Some Flame Retardants and Textile Chemicals, and Exposures in the Textile Manufacturing Industry. Summary of Data Reported and Evaluation. World Health Organization : Paris, France.
17. ↑ Juliane Gluge, Lena Schinkel, Konrad Hungerbühler , Ronan Cariou, Christian Bogdal: Environmental Risks of Medium-Chain Chlorinated Paraffins (MCCPs): A Review. In: Environmental Science & Technology . 2018, 52 (12), pp. 6743-6760; doi: 10.1021 / acs.est.7b06459 .
18. ↑ Lena Schinkel, Sandro Lehner, Marco Knobloch, Peter Lienemann, Christian Bogdal, Kristopher McNeill, Norbert V. Heeb: Transformation of chlorinated paraffins to olefins during metal work and thermal exposure - Deconvolution of mass spectra and kinetics. In: Chemosphere . 2017, pp. 803-811; doi: 10.1016 / j.chemosphere.2017.11.168 .
19. ↑ Official Journal of the European Communities: Directive 2002/45 / EC of the European Parliament and of the Council of June 25, 2002 on the 20th amendment to Directive 76/769 / EEC of the Council with regard to restrictions on the placing on the market and use of certain dangerous substances and preparations ( short-chain chlorinated paraffins) by inclusion as number 42 of Annex I of Directive 76/769 / EEC with an obligation to review other uses of SCCP; Period regulation Art. 2
20. ↑ SC-8/11: Listing of short-chain chlorinated paraffins . P. 65, Stockholm Convention , May 2017.
21. ↑ Official Journal of the European Union : Commission Regulation (EU) No. 519/2012 of June 19, 2012 amending Regulation (EC) No. 850/2004 of the European Parliament and of the Council on persistent organic pollutants with regard to Annex I through inclusion as 3rd entry in Annex I Part B (to Art. 3) of the POP-VO; Exception for unintentional trace contamination according to Art. 4 Para. 1 POP-VO; Articles used up to July 10, 2012 are therefore protected.
22. ↑ Chemical Risk Reduction Ordinance , Appendix 1.1 , as of June 20, 2017.
23. ↑ Official Journal of the European Union : Regulation (EU) 2015/2030 of the Commission of November 13, 2015 amending Regulation (EC) No. 850/2004 of the European Parliament and of the Council on persistent organic pollutants with regard to Annex I provided according to the reason (13) states that this is what can occur as an unintentional contamination when using MCCP in production, i.e. falls under the exception of Art. 4 Para. 1 POP-VO.
24. ↑ Chemical Risk Reduction Ordinance, amendment of October 25, 2017 .
25. ↑ § 1 Chemical Sanctions Ordinance with § 27 Chemicals Act .
26. ^ GT Tomy: Analysis of chlorinated paraffins in environmental matrices: the ultimate challenge for the analytical chemist. In: J. DeBoer (Ed.): Chlorinated Paraffins . 2010, pp. 84-106, doi: 10.1007 / 698_2009_39 .
27. ^ ^{A b} Christian Bogdal: Analysis methods for chlorinated paraffins for the enforcement of environmental regulations. ETH Zurich, 2018 (PDF) .
28. ↑ Lena Schinkel, Sandro Lehner, Norbert V. Heeb, Philippe Marchand, Ronan Cariou, Kristopher McNeill, Christian Bogdal: Dealing with strong mass interferences of chlorinated paraffins and their transformation products: An analytical guide . In: TrAC Trends in Analytical Chemistry . tape 106 , 2018, p. 116 , doi : 10.1016 / j.trac.2018.07.002 .