Hexamethyldisilane Property

Melting point:

9-12 °C (lit.)

Boiling point:

112-114 °C (lit.)

Density 

0.715 g/mL at 25 °C (lit.)

refractive index 

n20/D 1.422(lit.)

Flash point:

29 °F

storage temp. 

Store at <= 20°C.

solubility 

sol common organic solvents; insol H2O.

form 

liquid

Specific Gravity

0.729

color 

colorless

Water Solubility 

Insoluble in water. Soluble in alcohol, ether and acetone.

Hydrolytic Sensitivity

1: no significant reaction with aqueous systems

BRN 

1633463

Stability:

Volatile

InChIKey

NEXSMEBSBIABKL-UHFFFAOYSA-N

CAS DataBase Reference

1450-14-2(CAS DataBase Reference)

NIST Chemistry Reference

Disilane, hexamethyl-(1450-14-2)

EPA Substance Registry System

Disilane, hexamethyl- (1450-14-2)

Safety

Hazard Codes 

F,Xi

Risk Statements 

11-36/37-43-36/37/38

Safety Statements 

16-23-45-9-33-26-7/9

RIDADR 

UN 1993 3/PG 2

WGK Germany 

2

RTECS 

JM9170000

TSCA 

Yes

HazardClass 

3

PackingGroup 

II

HS Code 

29310095

Toxicity

LD50 orally in Rabbit: 2160 mg/kg LD50 dermal Rabbit 2160 mg/kg

Hazard and Precautionary Statements (GHS)

Symbol(GHS)

Signal word

Danger

Hazard statements

H225Highly Flammable liquid and vapour

H317May cause an allergic skin reaction

H319Causes serious eye irritation

H335May cause respiratory irritation

Precautionary statements

P210Keep away from heat/sparks/open flames/hot surfaces. — No smoking.

P280Wear protective gloves/protective clothing/eye protection/face protection.

P302+P352IF ON SKIN: wash with plenty of soap and water.

P305+P351+P338IF IN EYES: Rinse cautiously with water for several minutes. Remove contact lenses, if present and easy to do. Continuerinsing.

Hexamethyldisilane Chemical Properties,Usage,Production

Chemical Properties

Colorless clear liquid

Uses

Hexamethyldisilane acts as a silylating reagent for allylic acetates, aryl halides and diketones. It is a source material for vapor deposition during silicon carbide growth. It is also used in electronic and semiconducter industries.

Application

Hexamethyldisilane is an important silane protective agent, which can synthesize sodium trimethylsilane, potassium trimethylsilane and lithium trimethylsilane.
Preparation of iodotrimethylsilane.
Used as trimethylsilane anion reagent.
silylating or reducing reagent in combination with a Pd catalyst or a nucleophile.
Replaces aromatic nitriles with TMS groups in presence of [RhCl(cod)]2.
Precursor for CVD of silicon carbide.
Brings about the homocoupling of arenesulfonyl chlorides in the presence of Pd2(dba)3.
Used as a solvent for the direct borylation of fluoroaromatics.
Reacts with alkynes to form siloles.
Undergoes the silylation of acid chlorides to give acylsilanes.

Preparation

Hexamethyldisilane is produced by the reaction of methyl Grignard reagent with methylchlorodisilanes. This reaction is normally conducted in the presence of an ether such as diethyl ether, ethyl propyl ether, THF and the like.

Fire Hazard

Hexamethyldisilazane (HMDZ) is a highly flammable liquid and vapour.
HMDZ liquid is lighter than water and may float on water, spreading material during fire fighting. Leaking material or fire runoff to sewer may create fire or explosion hazard.
HMDZ vapours are heavier than air and can accumulate to form explosive concentrations. The vapours may also spread a considerable distance to a source of ignition, and flash back towards the source.
HMDZ reacts with water to form ammonia.
HMDZ is a non-conductor and, therefore, can accumulate static electrical charges when processed, handled or dispensed. HMDZ's flash point is 52 to 53°F, closed cup, for "pure" material.

Purification Methods

The most likely impurity is trimethylchlorosilane (cf boiling point). Wash it with H2O, cold conc H2SO4, H2O again, then aqueous NaHCO3, dry over CaSO4 and fractionate at atmospheric pressure. [Brown & Fowles J Chem Soc 2811 1958.] A grossly impure sample (25% impurities) was purified by repeated spinning band distillation. This lowered the impurity level to 500ppm. The main impurity was identified as 1-hydroxypentamethyldisilane. [Beilstein 4 IV 4277.]