Method for the production of MDI dimer

Patent metadata

Field	Value
Publication number	US-10047054-B2
Application number	US-201314078134-A
Country	US
Kind code	B2
Filing date	Nov 12, 2013
Priority date	Nov 13, 2012
Publication date	Aug 14, 2018
Grant date	Aug 14, 2018

Abstract

The invention relates to a method for the production of 4,4′-methylenebis(phenylisocyanate) dimer (MDI dimer) which is distinguished by an MDI dimer being obtained which is present in high purity. The MDI dimer which is produced according to the method according to the invention is distinguished by being essentially free of MDI and also urea derivatives. Furthermore, the invention relates to a corresponding MDI dimer and also the use thereof as crosslinker for polyurethanes.

First claim

The invention claimed is:

1. A method for the production of 4,4′-methylenebis(phenylisocyanate) dimer (MDI dimer) having the following steps in the following order:
a) providing only one solvent for 4,4′-methylenebis(phenylisocyanate) (MDI) in an inert gas atmosphere, said only one solvent and said inert gas being maintained at >25° C. to 45° C., and the only one solvent comprising a dimerization catalyst,
b) adding a melted MDI and/or MDI dissolved in a solvent consisting of the same solvent as the only one solvent of step a) with stirring over a timespan of 0.5 to 3 hours,
c) adding a deactivator for stopping the dimerization, with the proviso that stirring takes place in addition over a timespan of 0.5 to 1.5 hours at a temperature of >25° C. to 45° C., wherein the deactivator is selected from the group consisting of strong acids, acid chlorides, and acid anhydrides,
d) separating the obtained MDI dimer from the only one solvent and
e) purifying the obtained MDI dimer, wherein during the purification of the MDI dimer, the solvent utilized consists of the same solvent as the only one solvent of step a) and the MDI is washed twice with the same solvent;
wherein the only one solvent of step a) is selected from the group consisting of acetone, N-methylpyrrolidone, benzene, ethylacetate, acetonitrile, nitromethane, kerosine, and octane; and the water content of the only one solvent is maximum 0.04% by weight, and
wherein the MDI dimer produced by the method has a monomeric MDI content of less than 0.1 wt.-%.

2. The method according to claim 1 , wherein, in step a), a temperature in the range of 30° C. to 40° C. is maintained and the melted and/or the dissolved MDI is added in step b) in drops.

3. The method according to claim 1 , wherein the inert gas is selected from nitrogen, argon and helium.

4. The method of claim 3 , wherein the nitrogen, argon and/or helium has a water content of max. 0.01% by volume.

5. The method according to claim 1 , wherein the dimerization catalyst is selected from the group consisting of tertiary phosphines, amino-substituted phosphines, imidazoles, guanidines, pyridines substituted in position 3 or 4, pyridines substituted in positions 3 and 4, cyclic amidines, antimony pentafluoride, boron trifluoride and mixtures thereof.

6. The method of claim 5 , wherein the dimerization catalyst is selected from the group consisting of tertiary, aliphatic or mixed aliphatic-aromatic phosphines, trialkylphosphines, tris(N,N-dialkylamino)phosphines, dialkylimidazoles, 4-N,N-dialkylaminopyridines, pyridines which are substituted by N atoms in positions 3 and 4 and which are connected via carbon segments, and mixtures thereof.

7. The method of claim 6 , wherein the dimerization catalyst is selected from the group consisting of tris(N,N-dialkylamino)phosphines, 1,2-dialkylimidazoles, 4-N,N-dialkylaminopyridines and mixtures thereof.

8. The method of claim 7 , wherein the dimerization catalyst is selected from the group consisting of tris(N,N-dimethylamino)phosphine, tris(N,N-diethylamino)phosphine, 4-N,N-dimethylaminopyridine, 4-N,N-diethylaminopyridine, 1,2-dimethylimidazole, 1,2-diethylimidazole and mixtures thereof.

9. The method of claim 6 , wherein the carbon segments are binary, saturated carbon segments.

10. The method according to claim 1 wherein the separation of the reaction product in step d) is effected by one or a combination of a plurality of mechanical separation methods for solid-liquid separation.

11. The method of claim 1 , wherein the deactivator is selected from the group consisting of chloroacetic acid, trichloroacetic acid, trifluoroacetic acid, methane sulphonic acid, perfluorobutane sulphonic acid, phosphoric acid, chloroformic acid, benzoyl chloride, dimethyl carbamide acid chloride, acetic acid anhydride, succinic acid anhydride, and mixtures thereof.

12. The method of claim 11 , wherein the deactivator is benzoyl chloride.

13. The method of claim 1 , wherein the only one solvent is ethyl acetate.

14. The MDI dimer obtained by a method according to claim 1 , wherein the MDI dimer has a content of monomeric MDI of less than 0.08% by weight.

15. The MDI dimer according to claim 14 , wherein said MDI dimer comprises no oligomeric products.

16. The MDI dimer of claim 15 , wherein the oligomeric products are trimers, tetramers, pentamers, and higher oligomers.

17. The MDI dimer according to claim 15 , wherein the MDI dimer is present in powder form.

18. The MDI dimer according to claim 17 , wherein the powder is composed of granulates and the average diameter d 50 of the granulates is in a range between 1 and 4 μm.

19. A method for cross-linking a polymer comprising reacting the MDI dimer of claim 14 with the polymer.

20. A method for the production of 4,4′-methylenebis(phenylisocyanate) dimer (MDI dimer) consisting of the following steps in the following order:
a) providing only one solvent for 4,4′-methylenebis(phenylisocyanate) (MDI) in an inert gas atmosphere, said only one solvent and said inert gas being maintained at >25° C. to 45° C., and the only one solvent comprising a dimerization catalyst; subsequently
b) adding a melted MDI and/or MDI dissolved in a solvent consisting of the same solvent as the only one solvent of step a) with stirring over a timespan of 0.5 to 3 hours; subsequently
c) adding a deactivator for stopping the dimerization, with the proviso that stirring takes place in addition over a timespan of 0.5 to 1.5 hours at a temperature of >25° C. to 45° C., wherein the deactivator is selected from the group consisting of strong acids, acid chlorides, and acid anhydrides; subsequently
d) separating the obtained MDI dimer from the only one solvent; and subsequently
e) purifying the obtained MDI dimer by solvent washing, wherein during the purification of the MDI dimer, the solvent utilized consists of the same solvent as the only one solvent of step a);
wherein the only one solvent is selected from the group consisting of acetone, N-methylpyrrolidone, benzene, ethylacetate, acetonitrile, nitromethane, kerosine, and octane; and the water content of the only one solvent is maximum 0.04% by weight,
wherein the MDI dimer produced by the method has a monomeric MDI content of less than 0.1 wt.-%.

21. The method of claim 20 , wherein the only one solvent is ethyl acetate.

Assignees

• Ems Patent Ag

Inventors

• Kaplan Andreas

Classifications

• C07D229/00 Primary

  Heterocyclic compounds containing rings of less than five members having two nitrogen atoms as the only ring hetero atoms · CPC title

• C08G18/82

  Post-polymerisation treatment · CPC title

• C08G18/79

  characterised by the polyisocyanates used, these having groups formed by oligomerisation of isocyanates or isothiocyanates · CPC title

• C07C263/18 Primary

  Separation; Purification; Stabilisation; Use of additives · CPC title

• C07C209/84

  Purification · CPC title