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Hexamethyldisilazane Basic information
Hexamethyldisilazane Chemical Properties
  • Melting point:-78 °C
  • Boiling point:125 °C(lit.)
  • Density 0.774 g/mL at 25 °C(lit.)
  • vapor density 4.6 (vs air)
  • vapor pressure 20 hPa (20 °C)
  • refractive index n20/D 1.407(lit.)
  • Flash point:57.2 °F
  • storage temp. 2-8°C
  • solubility Miscible with acetone, benzene, ethyl ether, heptane and perchloroethylene.
  • pka30(at 25℃)
  • form Liquid
  • color Colorless
  • Specific Gravity0.774
  • OdorAmmonia odour
  • PH Range8.5
  • explosive limit0.8-25.9%(V)
  • Water Solubility REACTS
  • Sensitive Moisture Sensitive
  • Hydrolytic Sensitivity7: reacts slowly with moisture/water
  • Merck 14,4689
  • BRN 635752
  • CAS DataBase Reference999-97-3(CAS DataBase Reference)
  • NIST Chemistry ReferenceSilanamine, 1,1,1-trimethyl-N-(trimethylsilyl)-(999-97-3)
  • EPA Substance Registry SystemHexamethyldisilazane (999-97-3)
Safety Information
  • Hazard Codes F,C,Xn
  • Risk Statements 11-20/21/22-34-52/53
  • Safety Statements 16-26-36/37/39-45-61
  • RIDADR UN 3286 3/PG 2
  • WGK Germany 2
  • RTECS JM9230000
  • 21
  • Autoignition Temperature325 °C
  • Hazard Note Flammable
  • TSCA Yes
  • HS Code 2931 90 00
  • HazardClass 3
  • PackingGroup II
  • Hazardous Substances Data999-97-3(Hazardous Substances Data)
  • ToxicityLDLO i.p. in mice: 650 mg/kg (Petrarch Systems Inc. Product Information Sheets)
Hexamethyldisilazane Usage And Synthesis
  • ReactionHexamethyldisilazane(HMDS) is an extremely versatile and strong silylating agent. It is primarily used for the protection of sensitive functional groups during chemical synthesis.One of the advantages of Hexamethyldisilazane over chlorosilanes is that no base is needed as a hydrochloric acid acceptor. It produces ammonia which escapes easily from the reaction mixture during silylation.
  • DescriptionHexamethyldisilazane is a bulk organo silicon compound, being a quite useful silanizing agent. It is a reagent for the preparation of trimethylsilyl derivatives. It can be used for silanizing the surface of silicon water, cellulose. It can also be used to dehydrate cells of biomaterials for scanning electron microscopy (SEM). The hexamethyldisilazane coatings on various nanoparticles make them be resistant to water contamination and flocculation during synthesis. It can also be used as a modifier to control the shape, formation of agglomerates surface area and pore size of silica particles. Moreover, it is an adhesion promoter for photoresist in photolithography, and is also useful in the pyrolysis-gas chromatography-mass spectrometry to enhance the detectability of compounds with polar functional groups.
  • Chemical PropertiesColorless liquid
  • UsesA reagent for the preparation of trimethylsilyl derivatives.
  • UsesDeactivation of chromatographic support materials. In electronic industry as an adhesion promoter for photoresists on silicon.
  • UsesHexamethyldisilazane mainly used as methyl silane alkylation (such as amikacin, penicillin, cephalosporins and kinds of penicillin derivatives), hydroxyl protectants of antibiotics. It is used as surface treatment agent of diatomite, white carbon black, titanium and blond additives of photoresist in the semiconductor industry. It is used as treatment agent of tearing strength resistance. It is used as a solvent in organic synthesis and organometallic chemistry. It is used as an adhesion promoter for photoresist in photolithography. it is used for the preparation of trimethylsilyl ethers from hydroxy compounds. It is used as an alternative to critical point drying during sample preparation in electron microscopy. It is added to analyte to get silylated diagnostic products during pyrolysis in gas chromatography- mass spectrometry.
  • DefinitionChEBI: An N-silyl compound obtained from ammonia by replacement of two of the hydrogens with trimethylsilyl groups. Hexamethyldisilazane is a derivatisation agent used in gas chromatography mass spectrometry applications.
  • General DescriptionA liquid. Boiling point of 260°F. Flash point 77°F. May be toxic by ingestion. Irritates skin and eyes. Vapors are heavier than air. May emit highly toxic nitrogen oxide fumes when heated to decomposition. Used to make other chemicals.
  • Air & Water ReactionsHighly flammable. Moisture sensitive.
  • Reactivity ProfileHexamethyldisilazane reacts with many carbonyl containing organic compounds to generate gaseous ammonia. May be incompatible with isocyanates, halogenated organics, peroxides, phenols (acidic), epoxides, anhydrides, and acid halides. Flammable gaseous hydrogen may be generated in combination with strong reducing agents, such as hydrides.
  • HazardFlammable, moderate fire risk.
  • Health HazardInhalation or contact with material may irritate or burn skin and eyes. Fire may produce irritating, corrosive and/or toxic gases. Vapors may cause dizziness or suffocation. Runoff from fire control or dilution water may cause pollution.
  • Purification MethodsA possible impurity is Me3SiCl. Wash it well with pet ether and fractionate it through a vacuum jacketed column packed with Helipac using a reflux ratio of 10:1. [Langer et al. J Org Chem 23 50 1958, Beilstein 4 IV 4014.]
  • ReferencesDeng, Xiang. "Hexamethyldisilazane." Synlett 2011.06(2011):881-882. Chiavari, G, D. Fabbri, and S. Prati. "Gas chromatographic-mass spectrometric analysis of products arising from pyrolysis of amino acids in the presence of hexamethyldisilazane." Journal of Chromatography A922.1–2(2001):235-241.
    Nation, J. L. "A new method using hexamethyldisilazane for preparation of soft insect tissues for scanning electron microscopy." Stain Technology 58.6(1983):347-51. lang=en®ion=US lang=en®ion=US lang=en®ion=US
Hexamethyldisilazane Preparation Products And Raw materials
Hexamethyldisilazane(999-97-3)Related Product Information
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