998-30-1Relevant articles and documents
How a Thermally Unstable Metal Hydrido Complex Can Yield High Catalytic Activity Even at Elevated Temperatures
Ehm, Christian,Krüger, Juliane,Lentz, Dieter
, p. 9305 - 9310 (2016)
Despite their instability in ethereal solvents, organotitanium hydride catalysts are successfully employed in catalysis at moderate to high temperatures (110 °C), even in the presence of alcohols. It is shown computationally (bond dissociation energy (BDE) analysis and energetic profile for regeneration) and experimentally (EPR studies and kinetic studies), with the specific example of hydrodefluorination (HDF), that despite the long standing belief, regeneration of Ti?H bonds from Ti?F bonds using silanes is endergonic. The resulting low concentration of Ti?H species is crucial for the catalytic stability of those systems. The resting state in the catalysis is a Ti?F species. The most promising silanes for regeneration are not the ones that have the strongest Si?F bond, but the ones that show the largest difference in Si?F and Si?H BDEs.
Mechanochemical method of producing triethoxysilane
Temnikov,Anisimov,Chistovalov,Zhemchugov,Kholodkov,Zimovets,Vysochinskaya, Yu. S.,Muzafarova
, p. 270 - 274 (2019/04/27)
A mechanochemical method for synthesis of triethoxysilane from silicon-copper contact mass and ethyl alcohol in the developed vibration reactor is presented. It is shown that the process of a direct alkoxysilane synthesis in the vibro-boiling layer is affected by a series of control parameters such as the ratio between the contact mass and the mass of grinding bodies, the grinding body sizes and their ratios in a polydisperse mixture, power density. Optimization of these parameters allowed us to obtain HSi(OEt)3 with a selectivity of 50% at a silicon conversion of 90% without the use of promoters.
Mechanochemistry-a new powerful green approach to the direct synthesis of alkoxysilanes
Temnikov, Maxim N.,Anisimov, Anton A.,Zhemchugov, Pavel V.,Kholodkov, Dmitry N.,Goloveshkin, Alexander S.,Naumkin, Alexander V.,Chistovalov, Sergey M.,Katsoulis, Dimitris,Muzafarov, Aziz M.
supporting information, p. 1962 - 1969 (2018/05/23)
The present work shows a new one-stage mechanochemical method for the direct synthesis of alkoxysilanes by silicon mechanoactivation followed by a reaction with an alcohol. Alkoxysilanes were obtained with nearly complete silicon and alcohol conversion. This method allows for a considerable simplification of the traditional multistage process by eliminating three stages that include silicon and catalyst preparation, and adapts it to green chemistry requirements. Vibration milling removed the oxide film, and the mechanoactivation of the large silicon fraction (1000-2000 μm) occurs in the reactor working space. Abrasion of the reactor walls and grinding bodies made of brass results in a developed catalytic surface on silicon, as it has been proven by a set of physical analytical methods such as scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), powder X-ray diffraction (PXRD), and X-ray photoelectron spectroscopy (XPS).