Alkoxy-functional organohydrogensiloxane oligomer synthesis

The patent removes the harmful acetoxy groups from the final product structure by using alternative promoters that do not introduce these groups. The method employs a two-step process: first performing hydrosilylation with a promoter that gives high beta-isomer selectivity, then removing any remaining acetoxy groups through treatment with basic alumina or other basic materials, thereby extracting the harmful component while preserving the beneficial high yield and selectivity.

The patent converts the potentially harmful effect of acetoxy group presence into a beneficial purification process. By using basic alumina or other basic materials to treat the reaction product, the method exploits the basicity to selectively remove acetoxy groups through deacetylation, transforming the problem of acetoxy contamination into an opportunity for enhanced product purity and stability.

The patent extracts and removes the harmful acetoxy groups from the product structure through treatment with basic alumina or other basic materials. This extraction process eliminates the source of acetic acid release, preventing the catalytic condensation reactions that cause viscosity increase, while maintaining the high reaction efficiency achieved during the synthesis phase.

The patent introduces basic alumina or other basic materials as intermediary substances that mediate the removal of acetoxy groups. These intermediaries facilitate the deacetylation process by providing a basic environment that promotes the elimination of acetoxy groups without interfering with the overall reaction efficiency or requiring extreme conditions.

The patent applies preliminary action by using a two-step process: first performing the hydrosilylation reaction under optimized conditions with a promoter to achieve high beta-isomer selectivity and yield, then performing a secondary treatment step to remove any acetoxy groups. This preliminary optimization of reaction conditions followed by purification maintains overall process simplicity while dramatically improving productivity.

The patent changes key reaction parameters including the introduction of specific promoters (dimethylacetoxysilane or other silane compounds), adjustment of reaction temperature, and modification of catalyst amounts to achieve high yield and beta-isomer selectivity. These parameter changes transform the conventional simple one-step process into an optimized two-step process with superior productivity.