Octamethyl cyclotetrasiloxane 556-67-2 CAS NO.556-67-2

Octamethyl cyclotetrasiloxane (D4), a colorless, transparent or milky liquid, flammable, odorless, is a compound obtained from dimethyl dichlorosilane through hydrolysis synthesis process based on separation and distillation. It is an important intermediate in organosilicon industry. The main applications include preparation of silicone polymers such as methyl silicone oil, insulation and moisture-proof of radio parts, surface deactivator of gas chromatography glass capillary column, etc.

overview

Molecular formula: C8H24O4Si4

Molecular weight: 296.62

CAS login number: 556-67-2

EINECS login number: 209-136-7

Main use

The primary form of Octamethyl cyclotetrasiloxane is mainly used for ring opening polymerization into silicone oil, silicone rubber and silicone resin with different degrees of polymerization. These polymers are further processed into products for a wide range of applications in construction, electronics, textiles, automotive, personal care, food, mechanical processing and a small number of direct applications.

Physicochemical properties

Colorless oily liquid.

Sensitive to humidity.

Can be miscible with organic solvents, insoluble in water.

Relative density 0.9558

Melting point 17 ~ 18℃

Boiling point 175 ~ 176℃

Refractive index (n20D) 1.3968

Flash point 60℃

inflammable

Preparation method

The dimethyl dichlorosilane drops were added to the water, the temperature was maintained at 30-40℃, stratified, the acid water was removed, the oil was hydrolyzed with sodium hydroxide solution, the hydrolysate and 0.5%-2% potassium hydroxide were added to the pyrolysis kettle, and the pyrolysis was carried out at 120-140℃, 99.8kPa vacuum degree. The lysate was fractionated, and the fraction of 173-176℃ was collected to obtain octamethylcyclotetraxylsilane.

Safety data

Dangerous Goods Mark Xn (Hazardous)

Danger class code R53; R62 (has long term harmful effects on aquatic environment. There is a risk of impaired reproductive ability.)

Safety note S36/37; S46; S51; S61 (Wear appropriate protective clothing. Use appropriate protective gloves. In case of accidental swallowing, seek medical advice immediately (show the product container or label). Use only in well-ventilated areas. Avoid release into the environment. Refer to the specific instructions/safety data sheet.)

Dangerous Goods Transport number UN 1993

Octamethylcyclotetrasiloxane (D4), colorless transparent or milky white liquid, flammable, no peculiar smell, is a kind of product obtained by hydrolysis synthesis of dimethyldichlorosilane, separated and rectified obtained compound. It is an important intermediate in the silicone industry. The main uses include the preparation of silicone polymers such as methyl silicone oil, insulation and moisture resistance of radio parts, surface deactivation agent for gas chromatography glass capillary columns, etc.

 

Specification

 

Melting Point	17-18 °C (lit.)
Boiling Point	175-176 °C (lit.)
Density	0.956 g/mL at 25 °C (lit.)
Refractive Index	n20/D 1.396(lit.)
Flash point	140 °F
Storage Condition	Store below +30°C.
Solubility	<0.001g/l Hydrolysis
Appearance	liquid
Color	colorless
Water Solubility	INSOLUBL
InChIKey	HMMGMWAXVFQUOA-UHFFFAOYSA-N

 

 

Safety Information

 

Dangerous Goods Sign	Xn
Hazard Category Code	53-62-10
Safety Instructions	36/37-46-51-61
Dangerous Goods Transportation No	UN 1993 3/PG 3
WGK Germany	1
TSCA	Yes
Hazard Level	3
Packaging Category	III
HS CODE	2931909
Toxicity	LD50 oral in rat: 1540mg/kg