Hexamethyldisiloxane

  • Poly(dimethylsiloxane)
Formula
[(CH3)3Si]2O
Structure
Description
Fluid.
Uses
Hydraulic fluid organo silicate mlo 5277.

Registry Numbers and Inventories.
CAS
107-46-0
EC (EINECS/ELINCS)
203-492-7
EC Class
highly flammable
RTECS
JM9237000
RTECS class
Primary Irritant
UN (DOT)
1993
Beilstein/Gmelin
1736258
Beilstein Reference
4-04-00-04018
Swiss Giftliste 1
G-3640
Canada DSL/NDSL
DSL
US TSCA
Listed
Austrailia AICS
Listed
New Zealand
Listed
Japan ENCS (MITI)
Listed
Korea ECL
Listed

Properties.
Formula
C6H18OSi2
Formula mass
162.38
Melting point, °C
-59
Boiling point, °C
101
Vapor pressure, mmHg
51 (30 C)
Critical temperature
246
Critical pressure
18.9
Density
0.764 g/cm3 (20 C)
Solubility in water
Insoluble
Viscosity
0.488 cp (25 C)
Surface tension
15.7 g/s2 (20 C)
Refractive index
1.3774 (20 C)
Heat of vaporization
34.8 kJ/mol

Hazards and Protection.
Storage
Keep away from sources of ignition. Store in a cool, dry place. Store in a tightly closed container. Keep under a nitrogen blanket. Flammables-area.
Handling
Use spark-proof tools and explosion proof equipment. Avoid breathing dust, vapor, mist, or gas. Avoid contact with skin and eyes. Use only in a chemical fume hood.
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
Follow the OSHA respirator regulations found in 29CFR 1910.134 or European Standard EN 149. Always use a NIOSH or European Standard EN 149 approved respirator when necessary.
Small spills/leaks
Absorb spill with inert material, (e.g., dry sand or earth), then place into a chemical waste container. Remove all sources of ignition. Use a spark-proof tool.
Disposal code
24
Stability
No data.
Incompatibilities
Strong acids - strong bases - strong oxidizing agents.
Decomposition
Carbon monoxide, carbon dioxide, silicon oxide.

Fire.
Flash Point,°C
4
Autoignition, °C
340
Upper exp. limit, %
21.8
Lower exp. limit, %
0.5
Fire fighting
Wear a self-contained breathing apparatus in pressure-demand, MSHA/NIOSH (approved or equivalent), and full protective gear. Will burn if involved in a fire. Containers may explode in the heat of a fire. Extinguishing media: Use carbon dioxide or dry chemical.
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.
Poison_Class
-
Exposure effects
The toxological properties of this substance have not been fully investigated.
   Ingestion
The toxicological properties of this substance have not been fully investigated. May be harmful if swallowed.
   Inhalation
May cause respiratory tract irritation. The toxicological properties of this substance have not been fully investigated.
   Skin
Causes mild skin irritation.
   Eyes
May cause eye irritation.

First aid
 
   Ingestion
Get medical aid. Wash mouth out with water.
   Inhalation
Remove from exposure to fresh air immediately. If not breathing, give artificial respiration. If breathing is difficult, give oxygen. Get medical aid.
   Skin
Get medical aid. Flush skin with plenty of soap and water for at least 15 minutes while removing contaminated clothing and shoes.
   Eyes
Flush eyes with plenty of water for at least 15 minutes, occasionally lifting the upper and lower eyelids. Get medical aid.

Transport.
UN number
1993
Response guide
Hazard class
3
Packing Group
I; II; III
 
HS Code
2931 00 95