Process for preparing alkoxysilanes

A process for preparing an alkoxysilane of formula (I):

• R.sup.1.sub.a R.sup.2.sub.b R.sup.3.sub.c Si(OR.sup.4).sub.4-a-b-c(I)
• wherein R.sup.1 is a hydrogen atom, an alkyl radical, an alkenyl radical, an aryl radical or a halolalkyl radical;
• R.sup.2 is a hydrogen atom or an alkyl radical;
• R.sup.3 is a hydrogen atom or an alkyl radical;
• R.sup.4 is an alkyl radical or an alkoxyalkyl radical;
• and a, b and c are each, independently, 0, 1, 2 or 3 with the proviso that a+b+c.ltoreq.3, comprising:
• forming a two phase liquid reaction medium of an alcohol of formula (III):
• R.sup.4 OH (III)
• wherein R.sup.4 is as defined above, with a halosilane of formula (II):
• R.sup.1.sub.a R.sup.2.sub.b R.sup.3.sub.c SiX.sub.4-a-b-c (II)
• wherein X is fluorine, chlorine, bromine or iodine, dissolved in a nonpolar solvent that is immiscible with the alcohol, wherein the amount of alcohol of the alcohol phase is at least one fold stoichiometric excess in relation to said halosilane;
• and
• commencing the reaction between the alcohol of the alcohol phase with the halosilane in the nonpolar solvent phase, with the hydrogen halide product produced being removed from contact with the nonpolar solvent phase in which it is formed by dissolution into the alcohol phase.