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Octamethylcyclotetrasiloxane

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Octamethylcyclotetrasiloxane Basic information

Product Name:
Octamethylcyclotetrasiloxane
Synonyms:
  • JACS-556-67-2
  • uc7207
  • unioncarbide7207
  • vs7207
  • Octamethylcyclotetrasiloxane,98%
  • 1H-Benzimidazol-2-yl-carbamic Acid Methyl Ester-d4
  • 2-Benzimidazolecarbamic Acid Methyl Ester-d4
  • BAS-3460-d4
CAS:
556-67-2
MF:
C8H24O4Si4
MW:
296.62
EINECS:
209-136-7
Product Categories:
  • Organics
  • Silicon Compounds
  • Siloxanes
  • Silicone Series
  • Self Assembly&Contact Printing
  • Self-Assembly Materials
  • Si (Classes of Silicon Compounds)
  • Si-O Compounds
  • Intermediates & Fine Chemicals
  • Isotope Labeled Compounds
  • Pharmaceuticals
  • Organometallic Reagents
  • Organosilicon
  • SilanesOrganometallic Reagents
  • Chemical Synthesis
  • Contact Printing
  • Materials Science
  • Micro/NanoElectronics
  • Organometallic Reagents
  • Self Assembly &amp
  • Self-Assembly Materials
  • Silanes
  • 1
  • 556-67-2
Mol File:
556-67-2.mol
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Octamethylcyclotetrasiloxane Chemical Properties

Melting point:
17-18 °C (lit.)
Boiling point:
175-176 °C (lit.)
Density 
0.956 g/mL at 25 °C (lit.)
vapor density 
1 (vs air)
vapor pressure 
1.32hPa at 25℃
refractive index 
n20/D 1.396(lit.)
Flash point:
140 °F
storage temp. 
Store below +30°C.
solubility 
<0.001g/l Hydrolysis
form 
liquid
color 
colorless
Specific Gravity
0.956
explosive limit
0.4-11.7%(V)
Water Solubility 
INSOLUBLE
Sensitive 
Moisture Sensitive
Merck 
14,6747
BRN 
1787074
Dielectric constant
2.4(20℃)
InChIKey
HMMGMWAXVFQUOA-UHFFFAOYSA-N
LogP
6.98 at 21.7℃
CAS DataBase Reference
556-67-2(CAS DataBase Reference)
NIST Chemistry Reference
Cyclotetrasiloxane, octamethyl-(556-67-2)
EPA Substance Registry System
Octamethylcyclotetrasiloxane (556-67-2)
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Safety Information

Hazard Codes 
Xn
Risk Statements 
53-62-10
Safety Statements 
36/37-46-51-61
RIDADR 
UN 1993 3/PG 3
WGK Germany 
1
RTECS 
GZ4397000
TSCA 
Yes
HazardClass 
3
PackingGroup 
III
HS Code 
29319090
Hazardous Substances Data
556-67-2(Hazardous Substances Data)
Toxicity
LD50 oral in rat: 1540mg/kg

MSDS

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Octamethylcyclotetrasiloxane Usage And Synthesis

Chemical Properties

Octamethylcyclotetrasiloxane is also known as D4. It is an odorless, colorless non-oily silicone fluid which has C8H24O4Si4 as chemical formula. It is a cyclic organic silicon substance which can be used as monomer in the production of silicone polymers such as rubber, resins and greases.

Uses

Octamethylcyclotetrasiloxane is used as a monomer in the production of silicone polymers and as an intermediate in the production of other organosilicon substances.Further it finds its application in electronics, textiles, personal care products and household care products.
Polydimethylsiloxane by the Polymerization of Octamethylcyclotetrasiloxane: To a resin flask equipped with a thermometer, stirrer, and reflux eondenser is added 1000 gm of octamethylcyclotetrasiloxane. The siloxane is heated to 165°C, and then 0.14gm of a potassium hydroxide-isopropanol complex (neutral equivalent = 193.5) is added to give a Si : Κ ratio of 4470:1. In 25 min the stirrer begins to stall, and the polymer is now heated for 3(1/2) hr at 150°C to complete polymerization. The resulting polymer has an intrinsic viscosity of 1.5 dl/gm corresponding to a molecular weight of 804,600.

Definition

ChEBI: Octamethylcyclotetrasiloxane is a cyclosiloxane that is the octamethyl derivative of cyclotetrasiloxane. It is an organosilicon compound and a cyclosiloxane. It derives from a hydride of a cyclotetrasiloxane.

Preparation

Commercially Octamethylcyclotetrasiloxane is produced from dimethyldichlorosilane. Dimethyldichlorosilane is added dropwise to water, the temperature is maintained at 30-40°C, stratified, the acid water is released, the oily material is hydrolyzed with sodium hydroxide solution, the hydrolysate and 0.5%-2% potassium hydroxide are added to the cracking kettle and cracked at 120-140°C and 99.8 kPa vacuum. The cracked material is fractionated and the fraction is collected at 173-176°C to obtain octamethylcyclotetraoxysilane.

General Description

Octamethylcyclotetrasiloxane (D4) is a volatile methylsiloxane (VMS) with a relatively low molecular weight. This silicone fluid has a silicon-oxygen bond in a cyclic arrangement and methyl groups are attached to the silicon atom. D4 can be used in the manufacture of silicone based polymers for use in medical devices and personal care products.

Health Hazard

Octamethylcyclotetrasiloxane (D4) can interfere with the body’s hormones. In animals, it can affect the reproductive system.
D4 is classified as a category 1 endocrine disruptor by the European Commission. A 2018 study commissioned by the Danish EPA identified D4 as an endocrine disruptor. The Global Harmonized System Label Requirements classified D4 as suspected to produce reproductive toxicity. D4 was added to the Toxic Substances Control Act work plan due to reproductive toxicity, moderate environmental persistence, and high bioaccumulation potential.
Adverse reproductive effects including estrogenic effects have been observed in rodents. The European Chemicals Agency characterized D4 as a persistent, bioaccumulative, and toxic chemical, and designated D4 as a Substance of Very High Concern.

Flammability and Explosibility

Flammable

Safety Profile

A skin irritant. When heated todecomposition it emits acrid smoke and irritating vapors.

Purification Methods

The solid exists in two forms, m 16.30o and 17.65o. Dry it over CaH2 and distil it. Further fractionation can be effected by repeated partial freezing and discarding the liquid phase. [Osthoff & Grubb J Am Chem Soc 76 399 1954, Hoffman J Am Chem Soc 75 6313 1953, Beilstein 4 IV 4125.]

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