Octamethyltrisiloxane

CAS NO.：107-51-7
Empirical Formula: C8H24O2Si3
Molecular Weight: 236.53
MDL number: MFCD00008264
EINECS: 203-497-4
SAFETY DATA SHEET (SDS)
Update Date: 2026-01-13 11:17:38

What is Octamethyltrisiloxane?

Chemical properties

Octamethyltrisiloxane is clear colourless liquid.

The Uses of Octamethyltrisiloxane

Octamethyltrisiloxane is a linear silicone oligomer. It is used as an excipient Dimethicones in pharmaceutical and cosmetic applications can provide long lasting lubricant, smooth feel and spreads easily. Studies demonstrate that it is able to maintain the conformational stability of certain adsorbed proteins such as bovine serum albumin (BSA). Used in the methylation of mercury(II) salts.

What are the applications of Application

As a basis for silicone oils or fluids designed to withstand extremes of temp; as a foam suppressant in petroleum lubricating oil.

Definition

ChEBI: Octamethyltrisiloxane is an organosiloxane that is trisiloxane in which all the hydrogens have been replaced by methyl groups.

General Description

Poly(dimethylsiloxane) (PDMS), also known as dimethicone, is an organosilicon compound that is widely used as a siloxane based elastomer. It is a hydrophobic material with attractive physical and chemical properties such as elasticity, optical transparency, tunable surface chemistry, and low electrical conductivity.

Flammability and Explosibility

Flammable

Purification Methods

Distil it twice, the middle fraction from the first distillation is again distilled, and the middle fraction of the second distillation is used. [Patnode & Wilcock J Am Chem Soc 68 358, Wolcock J Am Chem Soc 68 691 1946, Thompson J Chem Soc 1908 1953, Beilstein 4 IV 4115.]

Properties of Octamethyltrisiloxane

Melting point:	-82 °C (lit.)
Boiling point:	153 °C (lit.)
Density	0.82 g/mL at 25 °C (lit.)
vapor density	>1 (vs air)
vapor pressure	5.3hPa at 25℃
refractive index	n20/D 1.384(lit.)
Flash point:	99 °F
storage temp.	Inert atmosphere,Room Temperature
solubility	Chloroform (Slightly), DMSO, Methanol (Slightly)
form	liquid
color	Colourless to Pale Yellow
Specific Gravity	0.82
Water Solubility	34μg/L at 23℃
Hydrolytic Sensitivity	1: no significant reaction with aqueous systems
Merck	14,6748
BRN	1753063
Dielectric constant	2.3（20℃）
Stability:	Hygroscopic
CAS DataBase Reference	107-51-7(CAS DataBase Reference)
EPA Substance Registry System	Trisiloxane, octamethyl- (107-51-7)

Safety information for Octamethyltrisiloxane

Signal word	Warning
Pictogram(s)	Flame Flammables GHS02
GHS Hazard Statements	H226:Flammable liquids
Precautionary Statement Codes	P210:Keep away from heat/sparks/open flames/hot surfaces. — No smoking. P233:Keep container tightly closed. P240:Ground/bond container and receiving equipment. P241:Use explosion-proof electrical/ventilating/lighting/…/equipment. P242:Use only non-sparking tools. P243:Take precautionary measures against static discharge.