832079-33-1Relevant articles and documents
Enhanced hydrolytic stability of siliceous surfaces modified with pendant dipodal silanes
Arkles, Barry,Pan, Youlin,Larson, Gerald L.,Singh, Mani
, p. 9442 - 9450 (2014/08/05)
Dipodal silanes possess two silicon atoms that can covalently bond to a surface. They offer a distinct advantage over conventional silanes commonly used for surface modification in terms of maintaining the integrity of surface coatings, adhesive primers, and composites in aqueous environments. New nonfunctional and functional dipodal silanes with structures containing pendant rather than bridged organofunctionality are introduced. The stability of surfaces in aqueous environments prepared from dipodal silanes with hydrophobic alkyl functionality is compared to the stability of similar surfaces prepared from the conventional silanes. In strongly acidic and brine environments, surfaces modified with dipodal silanes demonstrate markedly improved resistance to hydrolysis compared to surfaces prepared from conventional silanes. Pendant dipodal silanes exhibit greater stability than bridged dipodal silanes. The apparent equilibrium constant for the formation of silanol species by the hydrolysis of a disiloxane bond was determined as Kc=[SiOH]2/[Si-O-Si][H2O]= 6±1×10-5 and is helpful in understanding the enhanced hydrolytic stability of surfaces modified with dipodal silanes. Two feet are better than one! Nonfunctional and functional dipodal silanes with structures containing pendant rather than bridged organofunctionality were synthesized. Surfaces modified with pendant dipodal silanes were found to be more resistant to hydrolysis than the bridged structure with single-carbon separated (disilapropyl)silanes, demonstrating the greatest resistance to hydrolysis and best stability (see figure).
Processes for manufacturing organochlorosilanes and dipodal silanes and silanes made thereby
-
Page/Page column 6, (2010/02/10)
Processes are provided for producing organchlorosilanes and dipodal silanes in which an organic halide or alkene or chloralkene is reacted with a hydridochlorosilane in the presence of a quarternary phosphonium salt catalyst by providing sufficient heat to effect a dehydrohalogenative coupling reaction and/or a hydrosilylation reaction and venting the reaction to control reaction pressure and to remove gaseous byproducts from the reaction. The processes are preferably continuous using a catalyst in fluid form at reaction pressures not exceeding about 600 psi. The reactions may be carried out substantially isothermally and/or isobarically, for example in a plug flow reactor or continuous stirred tank reactor. The processes may produce novel silylated compounds including 1,2-bis(trichlorosilyl)decane or 1,2-bis(trimethoxysilyl)decane.