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Hexamethylcyclotrisiloxane

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Not to be confused with Cholecalciferol.
Hexamethylcyclotrisiloxane
Names
IUPAC name 2,2,4,4,6,6-hexamethyl-1,3,5,2,4,6-trioxatrisilinane
Other names
  • Hexamethyltrisiloxane
  • Dimethylsiloxane trimer
  • D3
  • D3
Identifiers
CAS Number
3D model (JSmol)
ChemSpider
ECHA InfoCard 100.007.970 Edit this at Wikidata
EC Number
  • 208-765-4
PubChem CID
UNII
CompTox Dashboard (EPA)
InChI
  • InChI=1S/C6H18O3Si3/c1-10(2)7-11(3,4)9-12(5,6)8-10/h1-6H3Key: HTDJPCNNEPUOOQ-UHFFFAOYSA-N
SMILES
  • C1(O(O(O1)(C)C)(C)C)C
Properties
Chemical formula [(CH3)2SiO]3
Molar mass 222.462 g·mol
Appearance Colorless or white solid
Density 1.02 g/cm
Melting point 64 °C (147 °F; 337 K)
Boiling point 134 °C (273 °F; 407 K)
Hazards
GHS labelling:
Pictograms GHS02: FlammableGHS07: Exclamation mark
Signal word Warning
Hazard statements H228, H315, H319, H335
Precautionary statements P210, P240, P241, P261, P264, P271, P280, P302+P352, P304+P340, P305+P351+P338, P312, P321, P332+P313, P337+P313, P362, P370+P378, P403+P233, P405, P501
Except where otherwise noted, data are given for materials in their standard state (at 25 °C , 100 kPa). Infobox references
Chemical compound

Hexamethylcyclotrisiloxane, also known as D3 and D3, is the organosilicon compound with the formula [(CH3)2SiO]3. It is a colorless or white volatile solid. It finds limited use in organic chemistry. The larger tetrameric and pentameric siloxanes, respectively octamethylcyclotetrasiloxane and decamethylcyclopentasiloxane, are of significant industrial interest, whereas 1,000–10,000 tonnes per year of the trimer is manufactured and/or imported in the European Economic Area.

Structure and reactions

Hexamethylcyclotrisiloxane adopts a planar structure and is considered strained. It reacts with organolithium reagents to give, after hydrolysis, dimethylsilanols:

[(CH3)2SiO]3 + 3 RLi → 3 RSi(CH3)2OLi
RSi(CH3)2OLi + H2O → RSi(CH3)2OH + LiOH

Safety and environmental considerations

The LD50 for the related pentamer (D5) is >50 g/kg in rats.

See also

References

  1. ^ Moretto, Hans-Heinrich; Schulze, Manfred; Wagner, Gebhard (2005). "Silicones". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. doi:10.1002/14356007.a24_057. ISBN 3-527-30673-0.
  2. "InfoCard – Hexamethylcyclotrisiloxane". ECHA. Retrieved 2018-07-20.
  3. Scott E. Denmark; Christopher R. Butler (2007). "Hexamethylcyclotrisiloxane". eEROS. doi:10.1002/047084289X.rn00784. ISBN 978-0-471-93623-7.
  4. Brook, Michael A. (2000). Silicon in Organic, Organometallic and Polymer Chemistry. New York: Wiley. p. 262. ISBN 0-471-19658-4.
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