decamethylcyclopentasiloxane
{{distinguish|sitocalciferol}}
{{Chembox
| Watchedfields = changed
| verifiedrevid = 477166341
| Name =
| ImageFile = Decamethylcyclopentasiloxane.svg
| ImageCaption = Structural formula
| ImageFile_Ref = {{chemboximage|correct|??}}
| ImageAlt = Skeletal formula of decamethylcyclopentasiloxane
| ImageFile1 = Decamethylcyclopentasiloxane-from-xtal-3D-bs-17-grey.png
| ImageSize1 = 180
| ImageCaption1 = Ball-and-stick model of the molecule as found in the crystal structure determined by single-crystal X-ray diffraction{{ Cite journal | url = https://dx.doi.org/10.5517/cc89wzd | title = CSD Communication YAGTOQ: decamethylpentasilsesquioxane | author = S. Parsons, D. Rankin, P. A. Wood | year = 2004 | website = Cambridge Structural Database: Access Structures | publisher = Cambridge Crystallographic Data Centre | doi = 10.5517/cc89wzd | access-date = 2021-08-18 }}
| ImageAlt1 = Ball-and-stick model of the decamethylcyclopentasiloxane molecule
| ImageFile3 = Dekametilsiklopentasiloksan.png
| ImageCaption3 = Sample of decamethylcyclopentasiloxane
| ImageSize3 = 180
| PIN = Decamethyl-1,3,5,7,9,2,4,6,8,10-pentaoxapentasilecane
| OtherNames = {{ubl|Cyclopentamethicone|Cyclic dimethylsiloxane pentamer|D5|D5|2,2,4,4,6,6,8,8,10,10-Decamethylcyclopentasiloxane|GreenEarth}}
| SystematicName =
|Section1 = {{Chembox Identifiers
| CASNo = 541-02-6
| CASNo_Ref = {{cascite|correct|CAS}}
| PubChem = 10913
| ChemSpiderID = 10451
| ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}}
| UNII = 0THT5PCI0R
| UNII_Ref = {{fdacite|correct|FDA}}
| EINECS = 208-764-9
| MeSHName = Decamethylcyclopentasiloxane
| RTECS = GY5945200
| Beilstein = 1800166
| ChEMBL = 1885178
| DrugBank = DB11244
| SMILES = C[Si]1(C)O[Si](C)(C)O[Si](C)(C)O[Si](C)(C)O[Si](C)(C)O1
| SMILES1 = O1[Si](O[Si](O[Si](O[Si](O[Si]1(C)C)(C)C)(C)C)(C)C)(C)C
| StdInChI = 1S/C10H30O5Si5/c1-16(2)11-17(3,4)13-19(7,8)15-20(9,10)14-18(5,6)12-16/h1-10H3
| StdInChI_Ref = {{stdinchicite|correct|chemspider}}
| InChI = 1/C10H30O5Si5/c1-16(2)11-17(3,4)13-19(7,8)15-20(9,10)14-18(5,6)12-16/h1-10H3
| StdInChIKey = XMSXQFUHVRWGNA-UHFFFAOYSA-N
| StdInChIKey_Ref = {{stdinchicite|correct|chemspider}}
| InChIKey = XMSXQFUHVRWGNA-UHFFFAOYAC
}}
|Section2 = {{Chembox Properties
| Formula = {{chem2|[(CH3)2SiO]5}}
| C=10|H=30|O=5|Si=5
| Appearance = Colourless liquid
| Density = 0.958 g/cm3
| MeltingPtK = 226
| BoilingPtC = 210
| Viscosity = 3.74 cP
| Solubility = 17.03±0.72 ppb (23 °C) {{cite journal |author1=Sudarsanan Varaprath |author2=Cecil L. Frye |author3=Jerry Hamelink | year = 1996 | title = Aqueous solubility of permethylsiloxanes (silicones) | journal = Environmental Toxicology and Chemistry | volume = 15 | issue = 8 | pages = 1263–1265 | doi = 10.1002/etc.5620150803|bibcode=1996EnvTC..15.1263V }}
| VaporPressure = 20.4±1.1 Pa (25 °C) {{cite journal |author1=Ying Duan Lei |author2=Frank Wania |author3=Dan Mathers | year = 2010 | title = Temperature-Dependent Vapor Pressure of Selected Cyclic and Linear Polydimethylsiloxane Oligomers | journal = Journal of Chemical & Engineering Data | volume = 55 | issue = 12 | pages = 5868–5873 | doi = 10.1021/je100835n}}
}}
|Section3 = {{Chembox Hazards
| ExternalSDS = [http://www.clearcoproducts.com/pdf/msds/cosmetic/MSDS-Cyclo-2245.pdf External MSDS]
| GHSPictograms = {{GHS02}}{{GHS08}}
| GHSSignalWord = Warning
| HPhrases = {{H-phrases|226|361|412|413}}
| PPhrases = {{P-phrases|201|202|210|233|240|241|242|243|273|280|281|303+361+353|308+313|370+378|403+235|405|501}}
| NFPA-H = 1
| NFPA-R = 0
| NFPA-F = 2
| FlashPtC = 73
}}
|Section4 = {{Chembox Related
| OtherFunction_label = Organosilicon compounds
| OtherFunction = Octamethylcyclotetrasiloxane
}}
|Section5 =
|Section6 =
}}
Decamethylcyclopentasiloxane, also known as D5 and D5, is an organosilicon compound with the formula {{chem2|[(CH3)2SiO]5}}. It is a colorless and odorless liquid that is slightly volatile.{{GESTIS|ZVG=3200|Name=Decamethylcyclopentasiloxan|Date=25. September 2015}} It is used in various cosmetic products. It also is used as a dry cleaning solvent and has been marketed as an "eco-friendly" and "green" alternative to perchloroethylene in the 2000s, under the tradename GreenEarth. Decamethylcyclopentasiloxane is persistent in nature and possibly bioaccumulative. Decamethylcyclopentasiloxane is considered non-toxic but its long-term health effects are unknown.
Use
The compound is classified as a cyclomethicone. Such fluids are commonly used in cosmetics, such as deodorants, sunblocks, hair sprays and skin care products. It is becoming more common in hair conditioners, as it makes the hair easier to brush without breakage. It is also used as part of silicone-based personal lubricants. D5 is considered an emollient.
In Canada, among the volume used in consumer products approximately 70% were for antiperspirants and 20% for hair care products.{{cite journal| author = Donald Mackay, Christina E. Cowan-Ellsberry, David E. Powell, Kent B. Woodburn, Shihe Xu, Gary E. Kozerski, Jaeshin Kim| year = 2015| title = Decamethylcyclopentasiloxane (D5) environmental sources, fate, transport, and routes of exposure| journal = Environmental Toxicology and Chemistry| volume = 34| issue = 12| pages = 2689–2702| doi = 10.1002/etc.2941| pmid = 26213270| doi-access = free| bibcode = 2015EnvTC..34.2689M}}
10,000–100,000 tonnes per year of D5 is manufactured and/or imported in the European Economic Area.{{cite web|url=https://echa.europa.eu/substance-information/-/substanceinfo/100.007.969|title=InfoCard – Decamethylcyclopentasiloxane|publisher=ECHA|access-date=2018-07-18}} Atmospheric emissions of D5 in the Northern Hemisphere were estimated to 30,000 tonnes per year.{{cite journal| author = Michael S. McLachlan, Amelie Kierkegaard, Kaj M. Hansen, Roger van Egmond, Jesper H. Christensen, Carsten A. Skjøth| year = 2010| title = Concentrations and Fate of Decamethylcyclopentasiloxane (D5) in the Atmosphere | journal = Environmental Science & Technology| volume = 44| issue = 14| pages = 5365–5370| doi = 10.1021/es100411w| pmid = 20568739| bibcode = 2010EnST...44.5365M}}
Decamethylcyclopentasiloxane has also been tried as a dry-cleaning solvent in the early 2000s. It was marketed as a more environmentally friendly solvent than tetrachloroethylene (the most common dry-cleaning solvent worldwide) despite being controlled in the EU for to its persistent, bioaccumulative and toxic characteristics.{{Citation |title=Commission Regulation (EU) 2018/35 of 10 January 2018 amending Annex XVII to Regulation (EC) No 1907/2006 of the European Parliament and of the Council concerning the Registration, Evaluation, Authorisation and Restriction of Chemicals (REACH) as regards octamethylcyclotetrasiloxane ('D4') and decamethylcyclopentasiloxane ('D5') (Text with EEA relevance. ) |date=2018-01-10 |url=http://data.europa.eu/eli/reg/2018/35/oj/eng |access-date=2023-08-10 |language=en}}
Production and polymerization
Commercially D5 is produced from dimethyldichlorosilane. Hydrolysis of the dichloride produces a mixture of cyclic dimethylsiloxanes and polydimethylsiloxane. From this mixture, the cyclic siloxanes including D5 can be removed by distillation. In the presence of a strong base such as KOH, the polymer/ring mixture is equilibrated, allowing complete conversion to the more volatile cyclic siloxanes:{{cite encyclopedia |first1=Hans-Heinrich |last1=Moretto |first2=Manfred |last2=Schulze |first3=Gebhard |last3=Wagner |title= Silicones |encyclopedia= Ullmann's Encyclopedia of Industrial Chemistry |publisher= Wiley-VCH |location= Weinheim |date= 2005 |doi=10.1002/14356007.a24_057 |isbn=3527306730 }}
:{{chem2|[(CH3)2SiO]_{5n} → n [(CH3)2SiO]5}}
where n is a positive integer.
D4 and D5 are also precursors to the polymer. The catalyst is again KOH.
Safety and environmental considerations
D5 is nontoxic with an LD50 of >50 g/kg for rats.
The environmental impacts of D5 and D4 have attracted attention because these compounds are pervasive. Cyclic siloxanes have been detected in some species of aquatic life.Wang, De-Gao; Norwood, Warren; Alaee, Mehran; Byer, Jonathan D.; Brimble, Samantha: Review of recent advances in research on the toxicity, detection, occurrence and fate of cyclic volatile methyl siloxanes in the environment, Chemosphere 2013, volume 93, pages 711–725. {{doi|10.1016/j.chemosphere.2012.10.041}} A scientific review in Canada has determined that “Siloxane D5 does not pose a danger to the environment”[http://www.ec.gc.ca/lcpe-cepa/515887B7-AF58-45B7-ADA9-B4ADF8F204DB/CdR-BoR-D5_eng.pdf Report of the Board of Review for Decamethylcyclopentasiloxane (Siloxane D5) established under Section 333(1) of the Canadian Environmental Protection Act of 1999, October 20, 2011] and a scientific assessment of D5 by the Australian government stated, "the direct risks to aquatic life from exposure to these chemicals at expected surface water concentrations are not likely to be significant."[https://www.nicnas.gov.au/chemical-information/imap-assessments/imap-assessments/tier-ii-environment-assessments/cvms "Cyclic volatile methyl siloxanes: Environment tier II assessment"] {{Webarchive|url=https://web.archive.org/web/20200527055124/https://www.nicnas.gov.au/chemical-information/imap-assessments/imap-assessments/tier-ii-environment-assessments/cvms |date=2020-05-27 }} Australian Department of Health. Retrieved 2018-12-04. However, in the European Union, D5 was characterized as a substance of very high concern (SVHC) due to its PBT and vPvB properties and was thus included in the candidate list for authorisation.{{cite web|url=https://echa.europa.eu/candidate-list-table/-/dislist/substance/external/100.007.969|title=Candidate List of substances of very high concern for Authorisation – Decamethylcyclopentasiloxane|publisher=ECHA|access-date=2018-07-18}} Since 31 January 2020, D5 cannot be placed on the market in the European Union in wash-off cosmetic products in a concentration equal to or greater than 0.1 % by weight.{{cite web|url=https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=CELEX:32018R0035|title=Commission Regulation (EU) 2018/35 of 10 January 2018 amending Annex XVII to Regulation (EC) No 1907/2006 of the European Parliament and of the Council concerning the Registration, Evaluation, Authorisation and Restriction of Chemicals (REACH) as regards octamethylcyclotetrasiloxane ('D4') and decamethylcyclopentasiloxane ('D5')|access-date=2018-07-18}}
See also
References
{{Reflist}}
External links
- {{CPID|id=3705|name=Cyclopentasiloxane}}
- {{cite journal|doi=10.1016/j.yrtph.2015.06.011|title=Toxicology of decamethylcyclopentasiloxane (D5)|last1=Dekant|first1=Wolfgang|last2=Klaunig|first2=James E.|journal=Regulatory Toxicology and Pharmacology|date=2016|volume=74|pages=S67–S76|pmid=26111607 |doi-access=free}}