Kinetics of the condensation of oligosiloxanes containing acetoxyl and hydroxyl end groups catalyzed by uncharged nucleophiles in an acid-base inert solvent
Hydrosilylation reaction of allylacetate (AA) with octakis(dimethylsiloxy)octasilsesquioxane [(HSiMe2O)8(SiO1.5)8] was efficiently catalyzed by chloro(1,5-cyclooctadiene)iridium(I) dimer [Ir(μ-Cl)(COD)]2. The effects of the catalyst amounts and the reaction conditions on the conversion and the product selectivity were investigated. [Ir(μ-Cl)(COD)]2 catalyst was also applied to the hydrosilylation
The acetolysis reactions of compounds of the type XSiMe2Cl (I) with acetic acid in the presence of acetic anhydride were studied kinetically by means of 1H NMR spectroscopy. We found these reactions exclusively influenced by steric effects (ϱ = 0)
通过1 H NMR光谱动力学研究了XSiMe 2 Cl(I)型化合物在乙酸酐存在下与乙酸的乙酰化反应。我们发现这些反应仅受空间位阻影响(ϱ = 0)
By-Product-Free Siloxane-Bond Formation and Programmed One-Pot Oligosiloxane Synthesis
reactions, such as hydrolysis/dehydration and cross‐coupling reactions, in which the generation of by‐products during bond formation can not be avoided. We have developed a one‐pot sequence of iridium‐catalyzed silyl ester hydrosilylation and boron‐catalyzed rearrangement of the resulting disilyl acetals for the construction of siloxane bonds, in principle without the formation of any by‐products. Moreover
Method for preparing acetoxysiloxanes and organo(poly)siloxanes having
申请人:Wacker-Chemie GmbH
公开号:US04680365A1
公开(公告)日:1987-07-14
Organo(poly)siloxanes having halogen bonded directly to silicon, or acetoxysiloxanes are prepared by reacting organo(poly)siloxanes having hydrogen bonded directly to silicon, with an allyl compound in the presence of metallic palladium, ruthenium or rhodium, or an acetylacetone or phosphine complex, or compound containing palladium, ruthenium or rhodium in which the allyl compound is an allyl halide having 3 carbon atoms per molecule or allyl acetate.
Silicone-containing contact lens material and contact lenses made thereof
申请人:Polymer Technology Corp.
公开号:US04826936A1
公开(公告)日:1989-05-02
According to the invention contact lenses are formed of unsaturated, multifunctional, organosiloxanes alone or mixed with monofunctional organosilanes and in some cases a hardening agent such as methyl methacrylate, hydrophilic monomer wetting agents, and itaconate hydrophilic and hardening agents. In the preferred embodiment, an additional hydrophilic cross-linking agent is used and the multifunctional organosiloxane is less than 50% of the organosiloxane used. The multifunctional organosiloxane adds higher impact strength and reduces brittleness, probably due to greater cross-linking density in the final product and retains the desirable properties of silicone-containing materials for use in contact lenses.