Siloxacycles are synthesized in high yield and purity by reaction of acyloxymethyl (alkoxy) silanes in the presence of a catalyst which is a metal from groups 3 to 15 of the periodic table, or a compound thereof.
Silanes containing an ester group are produced in high yield and purity by reacting a salt of a carboxylic acid with a silane containing a carboxylate substitutable leaving group following by distilling the product mixture to obtain a distillate containing the ester group containing silane product, wherein a solvent having a boiling point higher than the product is contained in the product mixture during at least a terminal portion of the distillation.
Siloxacycles are efficiently prepared from compounds of the formula
R
1
—C(═O)—[O—CH
2
—Si(R
2
)
2
]
n
—OR
3
(II)
by reaction in the presence of an alcohol and an acidic catalyst selected from organic resins with sulfo groups, acidic alumina, clay minerals, montmorillonites, acidic zeolites, iso- and heteropolyacids. The products can be produced in high yield and purity and are suitable for effectively end capping organopolysiloxanes.