Decamethylcyclopentasiloxane

Structural formula
General
Surname	Decamethylcyclopentasiloxane
other names	D 5
Molecular formula	C 10 H 30 O 5 Si 5
Brief description	colorless and odorless liquid
External identifiers / databases
CAS number 541-02-6 EC number 208-764-9 ECHA InfoCard 100,007,969 PubChem 10913 Wikidata Q414350
properties
Molar mass	370.72 g mol −1
Physical state	liquid
density	0.96 g cm −3
Melting point	−38 ° C
boiling point	210 ° C
Vapor pressure	20.4 ± 1.1 Pa (25 ° C) 0.16 hPa (20 ° C) 1.8 hPa (50 ° C)
solubility	almost insoluble in water (17.03 ± 0.72 ppb at 23 ° C)
Refractive index	1.3982
safety instructions
GHS labeling of hazardous substances no GHS pictograms H and P phrases H: no H-phrases P: no P-phrases
Authorization procedure under REACH	of particular concern : persistent, bioaccumulative and toxic ( PBT ), very persistent and very bioaccumulative ( vPvB )
As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions . Refractive index: Na-D line , 20 ° C

Decamethylcyclopentasiloxane is a colorless and odorless liquid. It belongs to the group of organosilicon compounds , i. that is, it is an organic compound in which the silicon atoms are directly bonded to carbon atoms.

properties

Decamethylcyclopentasiloxane forms flammable vapor-air mixtures at elevated temperatures. The compound has a flash point of 77 ° C. The explosion range is between 0.52% by volume as the lower explosion limit (LEL) and 7% by volume (820 g / m ³ ) as the upper explosion limit (UEL). The ignition temperature is 392 ° C. The substance therefore falls into temperature class T2.

use

Decamethylcyclopentasiloxane is used, for example, as a starting material for basic or acid-catalyzed ring-opening polymerization , for cosmetics and hygiene articles, in cleaning and polishing agents and as a gasoline additive. Consumption in Sweden between 1999 and 2003 was 10–20 t / year. 10,000 to 100,000 tonnes of octamethylcyclotetrasiloxane are produced or imported into or into the EEA annually. In Canada, around 70% of the use in consumer goods was deodorants and around 20% hair care products.

Risk assessment

Decamethylcyclopentasiloxane was assessed as dangerous for the aquatic environment based on a substance assessment by Environment Canada and Health Canada in 2008 and was placed on the corresponding list. The industry challenged the decision that substance assessment should lead to restrictions and demanded a "Board of Review". This came to the conclusion in October 2011 that decamethylcyclopentasiloxane exceeded the limit values ​​for persistence and bioaccumulation , but that the substance did not biomagnify . Furthermore, there is no evidence that the substance is toxic to organisms up to the solubility limit. Accordingly, adverse effects for organisms in air, water and sediments were excluded. The minister responsible accepted the conclusions, so that decamethylcyclopentasiloxane was removed from the list.

In the EU, on the other hand, washable cosmetic products with a decamethylcyclopentasiloxane concentration of 0.1 percent by weight or higher may not be placed on the market after January 31, 2020, since decamethylcyclopentasiloxane meets the criteria for the identification of very persistent and very bioaccumulating substances .

Web links

• Entry on Cyclopentasiloxane, decamethyl- in the Consumer Product Information Database
• Wolfgang Dekant, James E. Klaunig: Toxicology of decamethylcyclopentasiloxane (D5). In: Regulatory Toxicology and Pharmacology . 2015, doi: 10.1016 / j.yrtph.2015.06.011 .

Individual evidence

1. ↑ ^{a b c d e f g h i j k} Entry on decamethylcyclopentasiloxane in the GESTIS substance database of the IFA , accessed on July 3, 2018(JavaScript required) .
2. ^ Ying Duan Lei, Frank Wania, Dan Mathers: Temperature-Dependent Vapor Pressure of Selected Cyclic and Linear Polydimethylsiloxane Oligomers. In: Journal of Chemical & Engineering Data . 55, 2010, pp. 5868-5873, doi: 10.1021 / je100835n .
3. ↑ Sudarsanan Varaprath, Cecil L. Frye, Jerry Hamelink: Aqueous solubility of permethylsiloxanes (silicones). In: Environmental Toxicology and Chemistry . 15, 1996, pp. 1263-1265, doi: 10.1002 / etc.5620150803 .
4. ↑ Eugene G. Rochow : Introduction to the chemistry of silicones . Verlag Chemie GmbH, Weinheim 1952.
5. ↑ Entry in the SVHC list of the European Chemicals Agency , accessed on July 2, 2018.
6. ↑ ^{a b} E. Brandes, W. Möller: Safety-related parameters. Volume 1: Flammable Liquids and Gases. Wirtschaftsverlag NW - Verlag für neue Wissenschaft, Bremerhaven 2003.
7. ↑ ChemgaPedia: Silicone .
8. ↑ KemI-stat - Swedish product register.
9. ↑ Eva Brorström-Lundén, Lennart Kaj, Jeanette Andersson, Anna Palm Cousins, Mikael Remberger, Martin Schlabach, Norbert Schmidbauer: Screening of New Chemicals in Sweden: The Case siloxanes (PDF; 425 kB) . Workshop on Emerging environmental pollutants: Key Issues and Challenges. Stresa, Italy.
10. ↑ InfoCard on decamethylcyclopentasiloxane from the European Chemicals Agency (ECHA), accessed on April 18, 2018.
11. ↑ Donald Mackay , Christina E. Cowan-Ellsberry, David E. Powell, Kent B. Woodburn, Shihe Xu, Gary E. Kozerski, Jaeshin Kim: Decamethylcyclopentasiloxane (D5) environmental sources, fate, transport, and routes of exposure. In: Environmental Toxicology and Chemistry. 34, 2015, pp. 2689–2702, doi: 10.1002 / etc.2941 .
12. ^ Environment Canada and Health Canada: Screening assessment for the challenge decamethylcyclopentasiloxane (D5) , 2008.
13. ↑ Donald Mackay : Risk assessment and regulation of D5 in Canada: Lessons learned. In: Environmental Toxicology and Chemistry. 2015, doi: 10.1002 / etc.2934 .
14. ↑ Regulation (EU) 2018/35 of the Commission of 10 January 2018 amending Annex XVII of Regulation (EC) No. 1907/2006 of the European Parliament and of the Council on the Registration, Evaluation, Authorization and Restriction of Chemicals (REACH) Octamethylcyclotetrasiloxane ("D4") and Decamethylcyclopentasiloxane ("D5") .