The Synthesis and Polymerization of 1,3-Disubstituted Cyclohexanes

The synthesis of cis- and trans-1,3-diisocyanatocyclohexane is described. With water the cis-diisocyanate gave a bicyclic urea and a polyurea, which decomposed on heating to the bicyclic urea, and the trans-diisocyanate formed a polyurea. cis-1,3-Diisocyanatocyclohexane was polymerized using sodium cyanide as initiator to give soluble polymers which contained little or no residual isocyanato groups and hence cyclopolymerization had occurred. The polymers were thermally unstable and depolymerized quantitatively to monomer in the temperature range 270-370°. Two different structural units are possible for the cyclopolymer and the proportions of each unit were estimated by a quantitative aminolysis using di-n-butylamine. trans-1,3-Di-isocyanatocyclohexane did not polymerize under similar conditions.