Fourteen dimethyldialkoxysilanes are prepared by reacting dimethyldich
lorosilane with corresponding alcohols in the liquid phase. Their phys
icochemical properties are determined by standard methods and their te
ntative empirical formulae are elucidated. The thermal conductivity va
lues of dimethyldialkoxysilanes are determined using a two slab guarde
d hot plate apparatus over a temperature range of 30-190-degrees-C. Th
e thermal conductivity values of dimethyldialkoxysilanes calculated fr
om empirical equations are found to vary from -14% to +19%. Because th
ermal conductivity is an important parameter in heat transfer calculat
ions, and to minimise the deviation of the values, new equations invol
ving easily measurable ultrasonic parameters have been formulated. The
proposed equations have been tested for the series of dimethyldialkox
ysilanes, tetraalkoxysilanes and polydimethylsiloxanes. The thermal co
nductivity values computed from the proposed equations are comparable
with experimental thermal conductivity values. Further, an equation in
volving the calculation of thermal conductivity values at varying temp
eratures is also proposed.