3530. Eicosamethylnonasiloxane

Nomenclature

CAS number: 2652-13-3
C20H60O8Si9; mol wt 681.46.
C 35.25%, H 8.87%, O 18.78%, Si 37.09%.

Description and references

Prepd by the reaction of hexamethyldisiloxane with octamethylcyclotetrasiloxane and sulfuric acid; by varying the proportions of these reactants, other methylpolysiloxanes of a desired average molecular weight may be prepd: Patnode, Wilcock, J. Am. Chem. Soc. 68, 362 (1946).

Chemical structure

Properties

Liquid. bp4.9 173°. d 0.918. nD20 1.3980. Stable. Inert to most chemical reagents and rubber. Maintains about the same viscosity over a wide temp range. Sol in benzene and the lighter hydrocarbons; slightly sol in alc and the heavy hydrocarbons.

Use

As a basis for silicone oils or fluids designed to withstand extremes of temp; as a foam suppressant in petr lubricating oil.