Methyldichlorosilane

  • Dichloromethylsilane
  • Methyl dichlorosilane
  • Dichloro(methyl)silane
Formula
CH4Cl2Si
Structure
Description
A colorless fuming liquid with a pungent odor.
Uses
Monomer for silicone fluids.

Registry Numbers and Inventories.
CAS
75-54-7
EC (EINECS/ELINCS)
200-877-1
RTECS
VV3500000
RTECS class
Primary Irritant
UN (DOT)
1242
Beilstein/Gmelin
1071194
Beilstein Reference
4-04-00-04096
Canada DSL/NDSL
NDSL
US TSCA
Listed
Austrailia AICS
Listed
New Zealand
Listed
Japan ENCS (MITI)
Listed

Properties.
Formula
CH4Cl2Si
Formula mass
115.04
Melting point, °C
-92.8
Boiling point, °C
41
Vapor pressure, mmHg
468 (25 C)
Vapor density (air=1)
3.97
Density
0.93 g/cm3 (0 C)
Solubility in water
Insoluble
Surface tension
35 g/s2
Refractive index
1.4 (20 C)
Partition coefficient, pKow
3.77
Heat of vaporization
27.1 kJ/mol
Heat of combustion
-1203 kJ/mol

Hazards and Protection.
Storage
Keep away from heat, sparks, and flame. Keep away from sources of ignition. Store in a tightly closed container. Keep under a nitrogen blanket. Store in a cool, dry, well-ventilated area away from incompatible substances. Flammables-area. Do not store in metal containers.
Handling
Wash thoroughly after handling. 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. Take precautionary measures against static discharges. Keep container tightly closed. Avoid contact with heat, sparks and flame. Avoid ingestion and inhalation. Do not allow contact with water. Use only in a chemical fume hood. Discard contaminated shoes. Do not pressurize, cut, weld, braze, solder, drill, grind, or expose empty containers to heat, sparks or open flames.
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 a chemical apron. Wear appropriate protective clothing to minimize contact with skin.
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. 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. Clean up spills immediately, using the appropriate protective equipment. Remove all sources of ignition. Use a spark-proof tool. A vapor suppressing foam may be used to reduce vapors. Do not get water on spilled substances or inside containers.
Stability
Stable under normal temperatures and pressures.
Incompatibilities
Copper, lead oxide, potassium permanganate, oxidizing agents (strong, e.g. bromine, hydrogen peroxide, nitrogen dioxide, potassium nitrate), silver.
Decomposition
Hydrogen chloride, carbon monoxide, carbon dioxide, silicon oxide.

Fire.
Flash Point,°C
-32
Autoignition, °C
230
Upper exp. limit, %
55
Lower exp. limit, %
3.4
Fire fighting
Wear a self-contained breathing apparatus in pressure-demand, MSHA/NIOSH (approved or equivalent), and full protective gear. Water Reactive. Material will react with water and may release a flammable and/or toxic gas. Use water spray to keep fire-exposed containers cool. Extremely flammable liquid. Containers may explode in the heat of a fire. Will be easily ignited by heat, sparks or flame. Contact with metals may evolve flammable hydrogen gas. Extinguishing media: DO NOT USE WATER! Do NOT get water inside containers. Do NOT use straight streams of water. Cool containers with flooding quantities of water until well after fire is out. For small fires use dry chemical, soda ash, lime or sand. For large fires use dry sand, dry chemical, soda ash or lime or withdraw.
Fire potential
Dangerous when exposed to heat or flame flammable liquid. Vapor forms flammable mixtures with air. Pure dichloro(methyl)silane is not ignited by impact, but it is in presence of potassium permanganate or trilead tetraoxide, or by copper or silver oxides, even under an inert gas. Trichlorosilane is highly flammable.
Hazards
Difficult to extinguish; reignition may occur. Contact with water applied to adjacent fires will generate irritating hydrogen chloride.
Combustion products
Toxic hydrogen chloride and phosgene gases may be formed.
Health
4
 
Flammability
3
 
 
Reactivity
2
 
 
Special
W

Health.
Exposure effects
   Ingestion
May cause severe and permanent damage to the digestive tract. Causes gastrointestinal tract burns.
   Inhalation
Causes chemical burns to the respiratory tract. Inhalation may be fatal as a result of spasm, inflammation, edema of the larynx and bronchi, chemical pneumonitis and pulmonary edema. Vapors may cause dizziness or suffocation.
   Skin
Causes skin burns.
   Eyes
Causes eye burns. May result in corneal injury. May cause conjunctivitis.

First aid
 
   Ingestion
Do NOT induce vomiting. If victim is conscious and alert, give 2-4 cupfuls of milk or water. Never give anything by mouth to an unconscious person. Get medical aid immediately.
   Inhalation
Get medical aid immediately. Remove from exposure to fresh air immediately. If not breathing, give artificial respiration. If breathing is difficult, give oxygen. DO NOT use mouth-to-mouth respiration.
   Skin
Get medical aid immediately. Immediately flush skin with plenty of soap and water for at least 15 minutes while removing contaminated clothing and shoes. Wash clothing before reuse. Destroy contaminated shoes.
   Eyes
Get medical aid immediately. Do NOT allow victim to rub or keep eyes closed. Extensive irrigation is required (at least 30 minutes).

Transport.
UN number
1242
Response guide
Hazard class
4.3
PRTC
T
Packing Group
I
 
USCG CHRIS Code
MCS
 
Std. Transport #
4916365