DI-TERT-BUTYLDICHLOROSILANE Property

Melting point:

−15 °C(lit.)

Boiling point:

190 °C729 mm Hg(lit.)

Density 

1.009 g/mL at 25 °C(lit.)

refractive index 

n20/D 1.457(lit.)

Flash point:

143 °F

storage temp. 

2-8°C

solubility 

sol most common organic solvents.

form 

liquid

Specific Gravity

1.009

color 

Colorless to Light yellow

Hydrolytic Sensitivity

8: reacts rapidly with moisture, water, protic solvents

Sensitive 

Moisture Sensitive

BRN 

1739236

CAS DataBase Reference

18395-90-9(CAS DataBase Reference)

EPA Substance Registry System

Silane, dichlorobis(1,1-dimethylethyl)- (18395-90-9)

Safety

Hazard Codes 

C

Risk Statements 

34-37

Safety Statements 

26-36/37/39-45

RIDADR 

UN 2987 8/PG 2

WGK Germany 

3

F 

10-21

TSCA 

No

HazardClass 

8

PackingGroup 

II

HS Code 

29319090

Hazard and Precautionary Statements (GHS)

Symbol(GHS)

Signal word

Danger

Hazard statements

H314Causes severe skin burns and eye damage

Precautionary statements

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

P303+P361+P353IF ON SKIN (or hair): Remove/Take off Immediately all contaminated clothing. Rinse SKIN with water/shower.

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

P363Wash contaminated clothing before reuse.

P405Store locked up.

DI-TERT-BUTYLDICHLOROSILANE Chemical Properties,Usage,Production

Physical properties

mp ?15°C; bp 190°C/729 mmHg; d 1.009 g cm?3.

Uses

Reagent used for preparing siliranes and protecting diols.

Uses

The presence of the bulky t-butyl groups in di-t-butyldichlorosilane has been found to increase the Si–C bond lengths slightly and to widen the CSiC bond angles by 11.1? relative to dichlorodimethylsilane as determined by electron diffraction and molecular mechanics calculations.
The di-t-butylsilylene protecting group for diols was introduced by Trost and Caldwell and used in a total synthesis of deoxypillaromycinone.It is introduced by the reaction of di-tbutyldichlorosilane with a 1,2- or 1,3-diol in acetonitrile in the presence of triethylamine and 1-hydroxybenzotriazole (HOBt) at 45–90°C (eq 1). For a related, highly reactive reagent see di-t-butylsilyl Bis(trifluoromethanesulfonate).

Preparation

can be conveniently prepared by chlorination of di-t-butylsilane (CCl4/PdCl2 (cat), 85%)but various other methods of preparation have been reported.

Purification Methods

Purify it by fractional distillation. 20 1.01. It is a colourless liquid with a pleasant odour and does not fume in moist air, but does not titrate quantitatively with excess of dilute alkali. [Tyler et al. J Am Chem Soc 70 2877 1948.] Di -tert-butyl silyl bis(trifluoromethanesulfonate) [85272 -31 -7] M 440.5, b 73.5 -7 4 . 5o/0.35mm, d 4 Purify it by fractional distillation at high vacuum. 20 1.36 (see pK for triflic acid). It is a pale yellow liquid which should be stored under argon. It is less reactive than the diisopropyl analogue. The presence of the intermediate monochloro compound can be detected by 1H NMR, (CHCl3): tert-Bu2Si(OTf)2 [ 1.25s], but impurities have 1.12s for tert-Bu2Si(H)OTf and 1.19s for tert-Bu2HSi(Cl)OTf. [Deslongchamps Tetrahedron Lett 23 4871 1982, Deslongchamps Aldrichimica Acta 17 72 1984.] TOXIC.