GB1265001A - - Google Patents

Abstract

1,265,001. Lithium-substituted silazanes. MIDLAND SILICONES Ltd. 25 March, 1969 [29 March, 1968; 11 July, 1968], Nos. 15280/68 and 33067/68. Heading C3S. Novel lithium-substituted cyclic silazanes of the formulµ wherein each R represents a C 1-4 alkyl or alkenyl radical or a phenyl radical, X represents hydrogen, lithium, a monovalent hydrocarbon radical or an inertly-substituted monovalent hydrocarbon radical, and Y represents a monovalent hydrocarbon radical, an inertly-substituted monovalent hydrocarbon radical, an -R 2 SiOLi radical, a silyl group or a siloxane residue, are prepared by reacting in the presence of an organic solvent (A) an alkyl, alkenyl or aryl lithium compound with (B) a compound of the general formulae wherein X<SP>1</SP> represents hydrogen, a monovalent hydrocarbon radical or an inertly-substituted monovalent hydrocarbon radical, and Z represents a monovalent hydrocarbon radical, an inertly-substituted monovalent hydrocarbon radical, a silyl group or a siloxane residue, to form intermediate cyclic silazane compounds having one or two lithium atoms directly attached to nitrogen in the cyclic structure, and thereafter allowing said intermediates, if necessary by increasing the temperature, to convert to cyclic structures having fewer ring members, whereby there is obtained by the reaction of (A) with (a) a compound of the general formula (1), or, when X<SP>1</SP> is hydrogen and sufficient of (A) is employed to react with both -NH groups in (a), a compound of the general formula (2), wherein Y is the -R 2 SiOLi radical, with the formation as an intermediate product of a compound having the general formula (1) in which X represents a lithium atom, and whereby there is obtained by the reaction of (A) with (b) a compound of the general formula (2). Uses.-as chemical intermediates, particularly for further reaction with organochlorosiloxanes and mono-, di-, tri- or tetrachlorosilanes to provide polymers or other monomers. In examples lithium-substituted silazanes of the above general formulµ are prepared and further reacted without isolation with dimethylvinylchlorosilane, (dimethylamino) dimethylchlorosilane and chlorotrimethylsilane to give as products 1 - pentamethyldisiloxanyl - 2,2,4,4, 6,6 - hexamethyl - 1,3 - diaza - 5 - oxa - 2,4,6- trisilacyclohexane, 1 - pentamethyldisiloxanyl- 3 - trimethylsilyl - 2,2,4,4,6,6 - hexamethyl- 1,3 - diaza - 5 - oxa - 2,4,6 - trisilacyclohexane, 1 - (1,1,3,3 - tetramethyl - 3 - vinyldisiloxanyl). 3 - dimethylvinylsilyl - 2,2,4,4,6,6 - hexamethyl - 1,3 - diaza - 5 - oxa - 2,4,6 - trisilacyclohexane, 1 - dimethylamino - dimethylsilyl- 3(3 - dimethylamino - 1,1,3,3 - pentamethyldisiloxanyl) - 2,2,4,4 - tetramethylcyclo-disilazane, and 1 - trimethylsilyl - 3 - pentamethyldisiloxanyl - 2,2,4,4 - tetramethylcyclodisilazane.