(2-MERCAPTOETHYL)TRIMETHYLSILANE Property

Boiling point:

144-146 °C(lit.)

Density 

0.839 g/mL at 25 °C(lit.)

refractive index 

n20/D 1.454(lit.)

Flash point:

85 °F

storage temp. 

2-8°C

solubility 

Soluble in MeOH, CH2Cl2, THF, and most organic solvents.

pka

10.80±0.10(Predicted)

BRN 

1732126

Safety

Hazard Codes 

Xi

Risk Statements 

10-36/37/38

Safety Statements 

26-36

RIDADR 

UN 1993 3/PG 3

WGK Germany 

3

RTECS 

KJ2621000

F 

13

HazardClass 

3.2

PackingGroup 

III

Toxicity

mouse,LD50,intraperitoneal,2500mg/kg (2500mg/kg),Doklady Akademii Nauk SSSR. Proceedings of the Academy of Sciences of the USSR. For English translation, see DBIOAM and DKBSAS. Vol. 229, Pg. 1011, 1976.

Hazard and Precautionary Statements (GHS)

Symbol(GHS)

Signal word

Warning

Hazard statements

H226Flammable liquid and vapour

H315Causes skin irritation

H319Causes serious eye irritation

H335May cause respiratory irritation

Precautionary statements

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

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.

(2-MERCAPTOETHYL)TRIMETHYLSILANE Chemical Properties,Usage,Production

Physical properties

bp 144–146 °C [52–54 °C (25 Torr)]; d 0.850.

Uses

2-(Trimethylsilyl)ethanethiol is a reagent used as a monoprotected sulfide dianion equivalent for the two-step installation of a divalent sulfur atom into organic molecules. It participates in the reactions of Thiol Substitution Reactions, Source of Sulfur Acid Derivatives, etc.

Preparation

The high commercial cost of 2-(trimethylsilyl)ethanethiol necessitates methods for its lab scale synthesis. The radical addition of thiolacetic acid to vinyltrimethylsilane occurs thermally to afford a 9:1 ratio of regioisomers, the 1- and 2-(trimethylsilyl)ethyl thiolesters of acetic acid (eq 1). Photochemical initiation may improve the ratio of regioisomers obtained. Purification of the thiolacetate by careful fractional distillation should be performed prior to conversion to the thiol in order to ensure high purity. The conversion to thiol is best performed with LAH3 or methanolic K2CO3, but ammonolysis may also be suitable. Saponification with KOH in water/ethanol is slightly less efficient. Direct radical addition of liquid H2S to vinyl trimethylsilane has been demonstrated, but the procedure is low-yielding and inconvenient.