Octamethyltrisiloxane

  • Pentamethyl(trimethylsilyloxy)disiloxane
  • Dimethylbis(trimethylsiloxy)silane
  • 1,1,1,3,3,5,5,5-Octamethyltrisiloxane
  • OS 20 (siloxane)
  • FRD 20
  • KF 96L1.0
Formula
C8H24O2Si3
Structure
Description
Colorless liquid.
Uses
Production of high temperature silicone oils or fluids.

Registry Numbers and Inventories.
CAS
107-51-7
EC (EINECS/ELINCS)
203-497-4
UN (DOT)
1993
Merck
12,6844
Beilstein/Gmelin
1753063
Beilstein Reference
4-04-00-04115
Canada DSL/NDSL
DSL
US TSCA
Listed
Austrailia AICS
Listed
New Zealand
Listed

Properties.
Formula
C8H24O2Si3
Formula mass
236.53
Melting point, °C
-82
Boiling point, °C
153
Vapor pressure, mmHg
50 (72 C)
Vapor density (air=1)
8.16
Density
0.82 g/cm3
Solubility in water
Insoluble
Surface tension
14.6 g/s2 (49.9 C)
Refractive index
1.384
Heat of vaporization
35.4 kJ/mol
Heat of combustion
-7787 kJ/mol

Hazards and Protection.
Storage
Keep away from heat, sparks, and flame. Store in a tightly closed container. Store in a cool, dry, well-ventilated area away from incompatible substances. Flammables-area. Store protected from moisture.
Handling
Wash thoroughly after handling. Remove contaminated clothing and wash before reuse. Use only in a well ventilated area. Ground and bond containers when transferring material. Use spark-proof tools and explosion proof equipment. Avoid contact with eyes, skin, and clothing. Empty containers retain product residue, (liquid and/or vapor), and can be dangerous. Avoid contact with heat, sparks and flame. Avoid ingestion and inhalation. Do not allow contact with water. Do not pressurize, cut, weld, braze, solder, drill, grind, or expose empty containers to heat, sparks or open flames. Keep from contact with moist air and steam.
Protection
Eyes: Wear appropriate protective eyeglasses or chemical safety goggles as described by OSHA's eye and face protection regulations in 29 CFR 1910.133 or European Standard EN166. Skin: Wear appropriate protective gloves to prevent skin exposure. Clothing: Wear appropriate protective clothing to prevent skin exposure.
Respirators
A respiratory protection program that meets OSHA's 29 CFR 1910.134 and ANSI Z88.2 requirements or European Standard EN 149 must be followed whenever workplace conditions warrant a respirator's use.
Small spills/leaks
Absorb spill with inert material, (e.g., dry sand or earth), then place into a chemical waste container. Avoid runoff into storm sewers and ditches which lead to waterways. Remove all sources of ignition. Use a spark-proof tool. Provide ventilation. Do not get water inside containers. A vapor suppressing foam may be used to reduce vapors.
Stability
Stable under normal temperatures and pressures. May decompose on exposure to moist air or water.
Incompatibilities
Moisture, water, strong oxidizing agents, strong acids.
Decomposition
Carbon monoxide, irritating and toxic fumes and gases, carbon dioxide, silicon oxide, formaldehyde.

Fire.
Flash Point,°C
29
Fire fighting
Wear a self-contained breathing apparatus in pressure-demand, MSHA/NIOSH (approved or equivalent), and full protective gear. During a fire, irritating and highly toxic gases may be generated by thermal decomposition or combustion. Will burn if involved in a fire. Use water spray to keep fire-exposed containers cool. Containers may explode in the heat of a fire. Extinguishing media: Use water spray to cool fire-exposed containers. Do NOT get water inside containers. Do NOT use straight streams of water. In case of fire, use carbon dioxide, dry chemical powder or appropriate foam.
Fire potential
HIGHLY FLAMMABLE: Will be easily ignited by heat, sparks or flames.
Hazards
Vapors may form explosive mixtures with air. Vapors may travel to source of ignition and flash back. Most vapors are heavier than air. They will spread along ground and collect in low or confined areas (sewers, basements, tanks). Vapor explosion hazard indoors, outdoors or in sewers.
Combustion products
Fire may produce irritating, corrosive and/or toxic gases.
Health
1
 
Flammability
3
 
 
Reactivity
1
 

Health.
Exposure effects
Effects may be delayed.
   Ingestion
May cause gastrointestinal irritation with nausea, vomiting and diarrhea. The toxicological properties of this substance have not been fully investigated. Ingestion of large amounts may cause CNS depression.
   Inhalation
The toxicological properties of this substance have not been fully investigated. Aspiration may lead to pulmonary edema. Vapors may cause dizziness or suffocation. May cause burning sensation in the chest.
   Skin
May cause irritation and dermatitis. May cause cyanosis of the extremities.
   Eyes
May cause eye irritation. May cause chemical conjunctivitis and corneal damage.

First aid
 
   Ingestion
Never give anything by mouth to an unconscious person. Get medical aid immediately. Do NOT induce vomiting. If conscious and alert, rinse mouth and drink 2-4 cupfuls of milk or water.
   Inhalation
Get medical aid immediately. Remove from exposure to fresh air immediately. If breathing is difficult, give oxygen. Do not use mouth-to-mouth respiration if victim ingested or inhaled the substance; induce artificial respiration with the aid of a pocket mask equipped with a one-way valve or other proper respiratory medical device.
   Skin
Get medical aid. Flush skin with plenty of soap and water for at least 15 minutes while removing contaminated clothing and shoes. Wash clothing before reuse.
   Eyes
Immediately flush eyes with plenty of water for at least 15 minutes, occasionally lifting the upper and lower eyelids. Get medical aid immediately.

Transport.
UN number
1993
Response guide
Hazard class
3
Packing Group
I; II; III