Octamethylcyclotetrasiloxane

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Structural formula
Structure of octamethylcyclotetrasiloxane
General
Surname Octamethylcyclotetrasiloxane
other names
  • D 4
  • OMCTS
Molecular formula C 8 H 24 O 4 Si 4
Brief description

colorless liquid with a faint odor

External identifiers / databases
CAS number 556-67-2
EC number 209-136-7
ECHA InfoCard 100.008.307
PubChem 11169
Wikidata Q2013804
properties
Molar mass 296.62 g · mol -1
Physical state

liquid

density

0.96 g cm −3 (20 ° C)

Melting point

17.5 ° C

boiling point

171-175 ° C

Vapor pressure

124.5 ± 6.2 Pa (25 ° C)

solubility

almost insoluble in water (56.2 ± 2.5 ppb at 23 ° C)

Refractive index

1.3968

safety instructions
GHS hazard labeling from  Regulation (EC) No. 1272/2008 (CLP) , expanded if necessary
02 - Highly / extremely flammable 08 - Dangerous to health

Caution

H and P phrases H: 226-361f-413
P: 210-273-308 + 313
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

Octamethylcyclotetrasiloxane ( D 4 ) is a colorless liquid with a faint odor. 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.

use

Octamethylcyclotetrasiloxane is used, for example, as a starting material for basic or acid-catalyzed ring-opening polymerization , for the production of rubber, vehicle care products , defoamers and in seals. It is also used as a reference substance in NMR spectroscopy . As one of the components of a mixture of substances known under the trade name Cyclomethicone (or Cyclemeticon), it is used in anti- head lice remedies as a carrier for the active ingredient dimeticone . Another area of ​​application is the hydrophobization of pyrogenic silica (Aerosil D4). The consumption in Sweden between 1999 and 2003 was 5–50 t / year. 100,000 to 1,000,000 tonnes of octamethylcyclotetrasiloxane are produced or imported into or into the EEA annually.

D 4 is one of the few known compounds that have a floor temperature during their polymerization .

regulation

In the EU, washable cosmetic products with an octamethylcyclotetrasiloxane concentration of 0.1 percent by weight or higher may not be placed on the market after January 31, 2020, since octamethylcyclotetrasiloxane meets the criteria for the identification of persistent, bioaccumulating and toxic substances as well as very persistent and very bioaccumulating substances Substances met.

Individual evidence

  1. ↑ a b c d e f Entry on octamethylcyclotetrasiloxane in the GESTIS substance database of the IFA , accessed on January 10, 2017(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 on Octamethylcyclotetrasiloxane in the Classification and Labeling Inventory of the European Chemicals Agency (ECHA), accessed on February 1, 2016. Manufacturers or distributors can expand the harmonized classification and labeling .
  6. ↑ Entry in the SVHC list of the European Chemicals Agency , accessed on July 2, 2018.
  7. ↑ ChemgaPedia: Silicone .
  8. ↑ KemI-stat - Swedish product register.
  9. ↑ Uni Regensburg: Standards in NMR Spectroscopy (PDF; 98 kB), accessed on March 24, 2013.
  10. ↑ Pigments series, Degussa Silicas, number 12, p. 14ff.
  11. ↑ 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.
  12. ↑ InfoCard on Octamethylcyclotetrasiloxane from the European Chemicals Agency (ECHA), accessed on April 18, 2018.
  13. ^ GG Odian: Principles of Polymerization. John Wiley and Sons, 2004, ISBN 0-471-27400-3 , pp. 79-81
  14. ↑ JE Brandrup, EH Immergut, EA Gulke: Polymer Handbook. 3rd edition, Wiley-Interscience, 1989, ISBN 0-471-81244-7 , p. 316.
  15. ↑ 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") .

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