Decamethylcyclopentasiloxane

  • Cyclic dimethylsiloxane pentamer
  • Dimethylsiloxane pentamer
  • Pentacyclomethicone
Formula
C10H30O5Si5
Structure
Description
Colorless liquid.
Uses
Intermediate for silicone fluids.

Registry Numbers and Inventories.
CAS
541-02-6
EC (EINECS/ELINCS)
208-764-9
RTECS
GY5945200
RTECS class
Primary Irritant
UN (DOT)
1993
Merck
12,2905
Beilstein/Gmelin
1800166
Beilstein Reference
4-04-00-04128
Canada DSL/NDSL
DSL
US TSCA
Listed
Austrailia AICS
Listed
New Zealand
Listed
Korea ECL
Listed

Properties.
Formula
C10H30O5Si5
Formula mass
370.77
Melting point, °C
-44
Boiling point, °C
101 (20 torr)
Density
0.958 g/cm3 (25 C)
Solubility in water
(20 C) insoluble
Refractive index
1.3980 (20 C)

Hazards and Protection.
Storage
Keep tightly closed. Keep away from heat and open flame. Store in a cool dry place.
Protection
Compatible chemical-resistant gloves. Chemical safety goggles.
Respirators
Government approved respirator.
Small spills/leaks
Cover with dry lime or soda ash, pick up, keep in a closed container, and hold for waste disposal. Ventilate area and wash spill site after material pickup is complete.
Stability
Stable at normal temperatures and pressures.
Incompatibilities
Strong oxidizing agents.
Decomposition
Carbon monoxide, Carbon dioxide, Silicon oxide, Formaldehyde.

Fire.
Flash Point,°C
55
Fire fighting
Extinguish using Carbon dioxide, dry chemical powder, or appropriate foam. Wear self-contained breathing apparatus and protective clothing to prevent contact with skin and eyes.
Fire potential
HIGHLY FLAMMABLE: Will be easily ignited by heat, sparks or flames.
Hazards
Emits toxic fumes under fire conditions. Combustible liquid.
Combustion products
Fire may produce irritating, corrosive and/or toxic gases.
Health
2
 
Flammability
2
 
 
Reactivity
0
 

Health.
Exposure effects
Properties of this material have not yet been prepared. Any recommendations are of a general nature. Many chemicals cause irritation of the eyes, skin, and respiratory tract. In severe cases respiratory tract irritation can progress to ARDS/acute lung injury which may be delayed in onset for up to 24 to 72 hours in some cases Irritation or burns of the esophagus or gastrointestinal tract are also possible if caustic or irritant chemicals are ingested. ALWAYS contact your local poision control authority or medical professional for assistance.
   Inhalation
Vapors may cause dizziness or suffocation. May cause irritation or burns.
   Skin
Causes skin irritation. Multiple Routes: May be harmful by inhalation, ingestion, or skin absorption. Vapor or mist is irritating to the eyes, mucous membranes, and upper respiratory tract.
   Eyes
See Skin.

First aid
 
   Ingestion
If swallowed, wash out mouth with water provided person is conscious. Call a physician.
   Inhalation
If inhaled, remove to fresh air. If not breathing give artificial respiration. If breathing is difficult, give oxygen.
   Skin
In case of contact, immediately wash skin with soap and copious amounts of water.
   Eyes
In case of contact, immediately flush eyes with copious amounts of water for at least 15 minutes.

Transport.
UN number
1993
Response guide
Packing Group
III
 
HS Code
2931 00 95