Hexamethyldisilazane

  • Di(trimethylsilyl)amine
  • 1,1,1,3,3,3-Hexamethyldisilazane
  • Silanamine, 1,1,1-trimethyl-N-(trimethylsilyl)-
  • Bis(trimethylsilyl)amine
  • SE 31 (silazane)
Formula
(CH3)3SiNHSi(CH3)3
Structure
Description
Colorless liquid.
Uses
Used to make other chemicals.

Registry Numbers and Inventories.
CAS
999-97-3
EC (EINECS/ELINCS)
213-668-5
EC Class
highly flammable, harmful, corrosive
R 11 20/21/22 34
S 16 26 36/37/39 45
RTECS
JM9230000
RTECS class
Tumorigen; Primary Irritant
UN (DOT)
1993
Merck
13,4708
Beilstein/Gmelin
635752
Beilstein Reference
4-04-00-04014
Canada DSL/NDSL
DSL
US TSCA
Listed
Austrailia AICS
Listed
New Zealand
Listed
Japan ENCS (MITI)
Listed
Korea ECL
Listed

Properties.
Formula
C6H19NSi2
Formula mass
161.41
Melting point, °C
-82
Boiling point, °C
126
Vapor pressure, mmHg
15 (25 C)
Vapor density (air=1)
4.6
Density
0.7742 g/cm3
Solubility in water
Reacts
Viscosity
0.9 cSt at 25 C
Refractive index
1.4080 (20 C)
Partition coefficient, pKow
2.32
Heat of combustion
-6462 kJ/mol

Hazards and Protection.
Storage
Keep away from heat, sparks, and flame. Keep away from sources of ignition. Store in a cool, dry place. Keep container closed when not in use. Store in a tightly closed container. Flammables-area.
Handling
Wash thoroughly after handling. Remove contaminated clothing and wash before reuse. Use only in a well ventilated area. Use spark-proof tools and explosion proof equipment. Avoid breathing dust, vapor, mist, or gas. Do not get in eyes, on skin, or on clothing. Empty containers retain product residue, (liquid and/or vapor), and can be dangerous. Take precautionary measures against static discharges. Avoid contact with heat, sparks and flame. Do not ingest or inhale. Use only in a chemical fume hood. 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 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. Clean up spills immediately, using the appropriate protective equipment. Scoop up with a nonsparking tool, then place into a suitable container for disposal. Remove all sources of ignition.
Disposal code
3
Stability
Stable under normal temperatures and pressures.
Incompatibilities
Strong oxidants and strong acids. May decompose upon exposure to moist air or water. When heated to temperatures above 150 C in the presence of air, hexamethyldisilazane can form formaldehyde vapors.
Decomposition
Nitrogen oxides, carbon monoxide, irritating and toxic fumes and gases, carbon dioxide, silicon oxide, formaldehyde.

Fire.
Flash Point,°C
6
Autoignition, °C
325
Upper exp. limit, %
25.9
Lower exp. limit, %
0.8
Fire fighting
Wear a self-contained breathing apparatus in pressure-demand, MSHA/NIOSH (approved or equivalent), and full protective gear. Extinguishing media: Do NOT use water directly on fire. Use foam, dry chemical, or carbon dioxide.
Fire potential
Flammable Liquid.
Hazards
Vapors can travel to a source of ignition and flash back.
Combustion products
Fire may produce irritating, corrosive and/or toxic gases.
Health
1
 
Flammability
3
 
 
Reactivity
1
 

Health.
Exposure effects
   Ingestion
May cause severe gastrointestinal tract irritation with nausea, vomiting and possible burns. May be harmful if swallowed.
   Inhalation
May cause irritation of the respiratory tract with burning pain in the nose and throat, coughing, wheezing, shortness of breath and pulmonary edema. Inhalation may be fatal as a result of spasm, inflammation, edema of the larynx and bronchi, chemical pneumonitis and pulmonary edema.
   Skin
Harmful if absorbed through the skin. Causes skin burns.
   Eyes
Causes eye burns.

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.
   Skin
Get medical aid. Immediately 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
 
HS Code
2931 00 95
 
Std. Transport #
4909375