4689. Hexamethyldisilazane

Nomenclature

CAS number: 999-97-3
1,1,1-Trimethyl-N-(trimethylsilyl)silanamine; HMDS.
C6H19NSi2; mol wt 161.39.
C 44.65%, H 11.87%, N 8.68%, Si 34.80%.

Description and references

Silylating agent. Prepn: R. O. Sauer, J. Am. Chem. Soc. 66, 1707 (1944). Surface tension and density as a function of temperature: R. S. Myers, H. L. Clever, J. Chem. Eng. Data 14, 161 (1969). Mass spec. study: J. Tamás, P. Miklos, Org. Mass Spectrom. 10, 859 (1975). Raman, IR and NMR spectra: K. Hamada, H. Morishita, Spectrosc. Lett. 16, 717 (1983). Molecular structure and conformation: T. Fjeldberg, J. Mol. Struct. 112, 159 (1984). Use in deactivation of chromatography columns: T. Welsch et al., J. Chromatogr. 241, 41 (1982); R. C. Kong et al., Chromatographia 18, 362 (1984). Use as adhesion promoter for photoresists: J. N. Helbert, H. G. Hughes in Proc. Symp. Adhesion Aspects Polymeric Coatings, K. L. Mittal, Ed. (Plenum Press, New York, 1983) pp 499-508; D. Freeman, W. Kern, J. Vac. Sci. Technol. A 7, 1446 (1989). Physical properties, toxicity and technical data: Petrarch Systems Inc. Product Information Sheets. Brief review of chemistry and applications: R. J. De Pasquale, Am. Lab. 5(6), 35-39 (1973).

Chemical structure

Properties

Colorless liquid with an ammonia-like odor. bp 126.0°. d420 0.7742. nD20 1.4080. Flash pt, closed cup: 81°F (27°C). pKa 7.55. Vapor pressure at 50°C: 79 mm. Viscosity: 0.90 cSt. Ignition pt: 380°. Dielectric constant (1000 Hz): 2.27. Insol in water, reacts slowly. LDLO i.p. in mice: 650 mg/kg (Petrarch Systems Inc. Product Information Sheets).

Caution

Causes severe burns to eyes and irritation of the skin (Petrarch Systems Inc. Product Information Sheets).

Use

Deactivation of chromatographic support materials. In electronic industry as an adhesion promoter for photoresists on silicon.