Beiträge zur chemie der SiN-Bindung, I Darstellung und Zerfall cyclischer N-silylierter Silazane
作者:Walter Fink
DOI:10.1002/hlca.19620450402
日期:——
Hexamethylcyclotrisilazan und Octamethylcyclotetrasilazan ergeben mit Butyllithium N-Lithiumcyclosilazane, die mit Trimethylchlorsilan umgesetzt N-silylierte Cyclosilazane liefern. Diese sind z. T. nicht stabil; sie zeigen Zerfallsreaktionen sowie inter- und intramolekulare Silylwanderungen; die stabilen Endprodukte sind zweifach N-silylierte cyclische Di-, Tri- und Tetrasilazane.
六甲基环三硅氮烷和八甲基环四硅氮烷和丁基锂N-环硅氮烷锂,三甲基氯硅烷基正硅烷基环利塞芬。Diese sind z。T. nicht stabil; sie zeigen Zerfallsreaktionen sowie interintermolekulare Silylwanderungen; 稳定生产的三氮杂四环硅四氮杂硅。
A process for preparing hexamethylcyclo-trisilazane by heating octamethylcyclotetra-silazane in the presence of a catalyst such as a Lewis acid or a sulfur compound of the following formula ##STR1## wherein M represents Ca, Mg, Al, Fe or NH.sub.4, R represents OH, a phenyl group or a substituted phenyl group, x is 0, 1 or 2 and y is 0, 1, 2 or 3 provided that x and y are not zero at the same time, and z is 0, 1, 2 or 3.
According to the method for preparing hexamethyl cyclotrisilazane of the present invention, hexamethyl cyclotrisilazane can be obtained by heating a linear or cyclic silazane compound represented by the following general formula: --(Me.sub.2 SiNH).sub.n -- (wherein Me represents a methyl group and n is an integer of not less than 4) in the presence of at least one catalytic compound selected from the group consisting of ammonium salts of arylsulfonic acids and/or aminoarylsulfonic acids and the resulting hexamethyl cyclotrisilazane represented by the formula: --Me.sub.2 SiNH).sub.3 -- can be recovered by distilling off the same outside the reaction system. According to the method of the present invention, highly pure hexamethyl cyclotrisilazane can be industrially prepared in good efficiency and in a high yield. In particular, if octamethyl cyclotetrasilazane which can be industrially prepared from cheap dimethyldichlorosilane is used as a starting material, hexamethyl cyclotrisilazane can also be prepared at a low cost. Thus, the method of the present invention has enough practical value in the organic silicon industries.
Si-N(M), Si-N(H, M) and M-N bonds and serve as bench-mark systems to study polar bonds by high-resolution low-temperature X-ray structure analysis. Experimentalchargedensitystudies reveal highly polar Si-N bonds with remarkable ionic contribution, even in the non-metallated starting material 1. The Li-N and Li-O bonds have to be classified as almost purely ionic bonds with topological properties not