Diisocyanates or mixtures of diisocyanates of the diphenylmethane class, processes for their preparation, as well as their use as synthesis components in the manufacture of polyurethanes by the isocyanate-polyaddition process

摘要

A diisocyanate corresponding to the general formula: IMAGE in which R1, R2 and R3 represent hydrogen or a C2-C12 alkyl group provided that two of the radicals R1, R2 and R3 represent hydrogen and the third represents an alkyl group containing from 2 to 12 carbon atoms. Mixtures of diisocyanates in which the described diisocyanate is a major substituent are also within the scope of this disclosure. Such compounds and mixtures are made by reacting a nitrobenzyl halide, an unsubstituted benzyl halide or a benzyl alcohol in the presence of a Friedel-Crafts catalyst with an alkylbenzene or a nitroalkylbenzene and then converting the nitro groups to amino groups by hydrogenation or reduction. The thus-produced amino compound is then phosgenated to form the diisocyanate. The compounds and mixtures of the present invention are useful in the production of polyurethane plastics.