Title:  Hexamethyldisilazane 
CAS Registry Number:  999-97-3 
CAS Name:  1,1,1-Trimethyl-N-(trimethylsilyl)silanamine 
Additional Names:  HMDS 
Molecular Formula:  C6H19NSi2 
Molecular Weight:  161.39 
Percent Composition:  C 44.65%, H 11.87%, N 8.68%, Si 34.80% 
Line Formula:  (CH3)3SiNHSi(CH3)3 
Literature 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). 
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). 
Boiling point:  bp 126.0° 
Flash point:  Flash pt, closed cup:  81°F (27°C) 
pKa:  pKa 7.55 
Index of refraction:  nD20 1.4080 
Density:  d420 0.7742 
Toxicity data:  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.   |