Abstract: By reacting a chloromonosilane or chlorodisilane with a halogenated hydrocarbon in a liquid phase in the presence of metallic aluminum or an aluminum alloy, a hydrocarbon group is substituted for at least one chlorine atom of the chlorosilane for introducing hydrocarbon into the chlorosilane. Silanes having a high degree of hydrocarbon substitution can be easily synthesized from chlorosilanes under moderate conditions and with high volumetric efficiency. The reagents used are aluminum or aluminum alloys and halogenated hydrocarbons which are inexpensive and readily available.

Abstract: Compounds of the formula ##SPC1##In which R represents an alkyl, alkenyl, cycloalkyl or aralkyl radical, one X represents a nitro group and the other X represents hydrogen and their mixtures. They are very suitable for the dyeing of synthetic fibres, such as fibres of polyesters.