Carbodiimides

Abstract

A process for the conversion of isocyanate groups in a refined organic isocyanate into carbodiimide groups which comprises heating said organic isocyanate with a catalyst of the formula: ##STR1## or the 2,3 or 3,4-mono-unsaturated analogues thereof, wherein R is an optionally substituted hydrocarbyl group, R.sup.1 to R.sup.8 which may be the same or different are hydrogen, chlorine or lower alkyl, X and Y may be chlorine or bromine or X and Y taken together may represent the divalent atoms =O or =S or the divalent radial =N aryl, followed by deactivation of the catalyst by adsorption on a substrate or by addition of one or more of the halides of hydrogen, phosphorus or tin or an oxyhalide of phosphorus or sulphur. When only partial conversion takes place the carbodiimides react with further isocyanate groups to give uretonimines. The products are useful for the manufacture of polymers especially microcellular polyurethanes.

Dependencies are inferred from the claim text.