The transformation
of silica (SiO
2
) to useful chemicals
is difficult to explore because of the strength of the Si–O
bond and thermodynamic stability of the SiO
2
structure.
The direct formation of alkoxysilanes from SiO
2
has been
explored as an alternative to the carbothermal reduction (1900 °C)
of SiO
2
to metallic silicon (Si
met
) followed
by treatment with alcohols. The base-catalyzed depolymerization of
SiO
2
with diols and monoalcohols afforded cyclic silicon
alkoxides and tetraalkoxysilanes, respectively. SiO
2
can
also be converted to alkoxysilanes in the presence of organic carbonates,
such as dimethyl carbonate. Alkoxysilanes can be further converted
to useful chemicals, such as carbamates, organic carbonates, and chlorosilanes.
An interesting and highly efficient pathway to the direct conversion
of SiO
2
to alkoxysilanes has been discussed in detail along
with the corresponding economic and environmental implications. The
thermodynamic and kinetic aspects of SiO
2
transformations
in the presence of alcohols are also discussed.