HEXAMETHYLDISILAZANE

PRODUCT IDENTIFICATION
CAS NO. 999-97-3

HEXAMETHYL DISILAZANE

EINECS NO. 213-668-5
FORMULA [(CH3)3Si]2NH
MOL WT. 161.39
H.S. CODE 2931.00.9010

UN NO.

3286

TOXICITY Oral rat LD50: 850 mg/kg
SYNONYMS 1,1,1,3,3,3-Hexamethyldisilazane; HMDS; Hexamethylsilazane;
1,1,1-Trimethyl-N-(trimethylsilyl)silanamine; 1,1,1,3,3,3-Hexametildisilazano (Spanish); 1,1,1,3,3,3-hexaméthyldisilazane (French); Bis(trimethylsilyl)amine; Other RN.: 18186-75-9, 103737-28-6, 127290-38-4, 761458-30-4
SMILES [Si](N[Si](C)(C)C)(C)(C)C

CLASSIFICATION

Silazane, Silylating Reagent. Solvent

EXTRA NOTES

 A reagent for the preparation of trimethylsilyl derivatives. Used for the silylation of alcohols, carboxylic acids, and thiols. Used for the protection of thioamides, hydroxamic acid, sulfamides, sulfonamides, phosphoramidates, hydrazines, hydrazides, pyrroles, imidazoles, indoles and N-substituted hydroxylamines.

PHYSICAL AND CHEMICAL PROPERTIES
PHYSICAL STATE

Clear liquid

MELTING POINT -78 C
BOILING POINT 126 - 128 C
SPECIFIC GRAVITY 0.765
SOLUBILITY IN WATER

Reacts

SOLVENT SOLUBILITY Reacts with methanol. Soluble in actone, benzene, ethyl ether, pentane and perchloroethylene
pH  
VAPOR DENSITY 4.6
log Pow 2.62 (Octanol-water)
VAPOR PRESSURE 13.8 (mmHg at 25 C)
HENRY LAW CONSTANT 8.69E-05 (atm-m3/mole at 25 C)
OH RATE CONSTANT 8.98E-13 (cm3/molecule-sec at 25 C Atmospheric )

AUTOIGNITION

379 C

NFPA RATINGS

 Health: 3 Flammability: 0 Reactivity: 0

REFRACTIVE INDEX

 1.4069 - 1.4089

FLASH POINT

20 C

STABILITY Stable under ordinary conditions. Moisture sensitive

EXTERNAL LINKS & GENERAL DESCRIPTION

Wikipedia Linking

Material Safety Data Sheet

Google Scholar Search

http://www.bioone.org/
The use of HMDS (hexamethyldisilazane) to Replace Critical Point Drying (CPD) in the Preparation of Tardigrades for SEM (Scanning Electron Microscope) Imaging

http://proj3.sinica.edu.tw/
Although many reagents are available for the silylation of hydroxyl groups, some of thesemethods suffered from serious obstacles such as low selectivity, long reaction times, low yields of products, toxicity, expensive reagents and catalysts, delicate purification step, lack of reactivity or the difficulty in removal of by-products. 1,1,1,3,3,3-Hexamethyldisilazane (HMDS) as a cheap, stable and commercially available reagent is one of the most widely used reagents for the silylation of hydroxyl groups. Its handling does not require special precautions, and the workup is not time-consuming, because the by-product of the reaction is ammonia, which is simple to remove from the reaction media. However, the low silylating power of HMDS is the main drawback to its application. Therefore to activate this reagent, an appropriate catalyst should be used. In continuation of our ongoing effort to develop new methods in organic functional group transformations, especially for the protection of the hydroxyl groups,

Local:
Hexamethyldisilazane (HMDS) is a strong hindered amine base but non-nucleophile (called harpoon base). The formula is (CH3)3Si-NH-Si(CH3)3 which consists of ammonia substituted with two trimethylsilyl groups. Silicon-consist alkali metal amides, such as Lithium hexamethyldisilazide (LiHMDS), Sodium hexamethyldisilazide (NaHMDS) are harpoon bases which are involved in kinetic deprotonation as the electron donor abstracts a proton. The advantages are that it is available as a solid and it is soluble in a wide range of nonpolar solvents. They are widely used in chemical reactions and transformation including Alkylation, base catalyzed reaction, condensation, dehalogenenation, deprotonations. elimination reaction, enolate formation, isomerization reaction, polymer application, selective metalation, super base application and transesterfication. Orher examples are Lithium diisopropylamide, Lithium tetramethylpiperidide, and alkali metal alcoholates.

SALES SPECIFICATION

APPEARANCE

Clear liquid

ASSAY

99.5% min

COLOR, APHA 5 max
TRANSPORTATION
PACKING 160kgs in drum
HAZARD CLASS 3 (Packing Group: II)
UN NO. 3286
SAFETY INFORMATION
Hazard Symbols: F C, Risk Phrases: 11-20/21/22-34, Safety Phrases: 7/8-9-16-26-29-36/37/39-45
PRICE INFORMATION