A process is disclosed for selectively making trans-cyclohexane-1,4-diisocyanate, trans-cyclohexane-1,4-diamine, a trans-cyclohexane-1,4-diurethane, a trans-cyclohexane-1,4-diurea and trans-cyclohexane-1,4-disulphonyl urea by reacting ammonia with a mixture of cis and trans cyclohexane-1,4-dicarboxylic acid, a lower alkyl ester, a glycol ester, an oligomeric ester or a polyester to make a solid trans-dicarboxylic acid diamide in a first step. The diamide is chlorinated to form trans-cyclohexane-1,4-dicarboxylic acid-bis-N-chloramide. The latter compound is then converted into a(a) trans-cyclohexane-1,4-diamine with an alkali metal hydroxide or alkaline earth metal hydroxide; or into a(b) a trans-cyclohexane-1,4-diurethane by reaction with an alcohol or glycol in a reaction mixture containing an alkali metal hydroxide or alkaline earth metal hydroxide; or into(c) a trans-cyclohexane-1,4-diurea by reaction with a primary or secondary amine in a reaction mixture containing an alkali metal hydroxide or alkaline earth metal hydroxide; or into a(d) trans-cyclohexane-1,4-sulphonyl urea by reaction with a primary sulphonamide in a reaction mixture containing an alkali metal hydroxide and dimethyl formamide and water. The diurea prepared in (c) may be converted into trans-cyclohexane-1,4-diisocyanate with gaseous hydrogen chloride in an inert solvent. The diurethane prepared in (b) and the disulphonyl urea prepared in (d) may be thermally decomposed into trans-cyclohexane-1,4-diisocyanate.