(Cyclo)condensation of isocyanate compounds
View Patent ↗The invention concerns the use of a compound comprising a nitrogenous heterocyclic group with five cyclic members including, at least two nitrogen atoms, one of the nitrogen atoms bearing a hydrogen atom to promote the opening/closing reaction of uretidione cycles in the presence of a nucleophile compound provided that, when the nitrogenous heterocyclic group is imidazole, the opening/closing reaction is not the closing reaction of the uretidione cycle in the presence of a quaternary ammonium salt.
1. A method for promoting the reaction of closing uretidione rings or of opening uretidione rings and their reaction with a nucleophilic compound having a mobile hydrogen atom, said method of closing uretdione rings comprising cyclodimerizing an aliphatic or cycloaliphatic isocyanate in the present of a nitrogenous heterocyclic compound having at least five ring members and at least two ring nitrogen atoms to form a uretidione dimer, and said method of opening uretidione rings comprising reacting a compound containing at least one uretidione ring derived from an aliphatic or cycloaliphatic isocyanate with a nucleophilic compound having a mobile hydrogen atom in the presence of a mtrogenous heterocyclic compound having at least five ring members and at least two ring nitrogen atoms, with the proviso that, when the nitrogenous heterocyclic compound is imidazole, the opening/closing reaction is not the reaction of closing isocyanate compounds to uretidione rings in the presence of a quatemary ammonium salt.
2. The method as claimed in claim 1 , wherein the nitrogenous heterocyclic compound is employed to promote the cyclodimerization of an aliphatic or cycloaliphatic isocyanate compound in the presence of an anionic compound, the isocyanate compounds being in excess with respect to the nitrogenous heterocyclic compound, with the proviso that the cyclodimerization is not carried out in the presence of quaternary amnmonium when the nitrogenous heterocyclic compound is imidazole.
3. The method as claimed in claim 1 , wherein the nitrogenous heterocyclic compound is employed to promote the reaction of opening a uretidione ring in the presence of a nucleophilic compound having a mobile hydrogen atom.
4. The method as claimed in claim 3 , wherein the nucleophilic compound is the reaction product of a base with an isocyanate group.
5. The method as claimed in claim 3 , wherein the nucleophilic compound is a compound having a functional group having a mobile hydrogen atom, the functional group reacting with the isocyanate functional group.
6. The method as claimed in claim 5 , wherein said nucleophilic compound is selected from the group consisting of amines, alcohols and thiols.
7. The method as claimed in claim 1 , wherein said nitrogenous heterocyclic compound is selected from the group consisting of imidazole, triazole, tetrazole and their derivatives comprising one or more substituents.
8. The method as claimed in claim 7 , wherein the nitrogenous heterocyclic compound is imidazole or one of its derivatives comprising one or more substituents.
9. The method as claimed in claim 2 , wherein said isocyanate is selected from the group consisting of tetramethylene diisocyanate, hexainethylene diisocyanate, 2-methylpentane diisocyanate, 3,3,5- or 3,5,5-trimethylhexamethylene dilsocyanates, bis(isocyanatomethylcyclohexane)norbornane diisocyanate, isophorone diisocyanate, 3-isocyanatomethyl-3,5,5-trimethylcyclohexyl isocyanate, 1,1-methylenebis(4,4-isocyanatocyclobexane).