Curing agent for low temperature cure applications
View Patent ↗The present invention discloses both amine compositions and amine-epoxy compositions containing N,N′-dimethyl-meta-xylylenediamine. A novel process for producing amines such as N,N′-dimethyl-meta-xylylenediamine, and structurally similar amines, is also disclosed.
1. A process for producing amines having the formula:
the process comprising:
(a) contacting a compound having the formula:
with methylamine or ethylamine in the presence of hydrogen and a catalyst at a hydrogen pressure of about 100 to about 500 psi to form at least one intermediate product; and
(b) contacting the at least one intermediate product with hydrogen in the presence of a hydrogenation catalyst at a hydrogen pressure of about 400 to about 1500 psi to form the amines having formula (I);
wherein:
R A is methyl;
R B is methyl;
R c in each occurrence is selected independently from a linear or branched C 1 -C 18 alkyl, a linear or branched C 1 -C 18 alkenyl, a linear or branched C 1 -C 18 alkoxy, and a linear or branched C 1 -C 18 alkoxyalkyl; and
x is 0, 1, 2, 3, or 4; wherein the at least one intermediate product comprises ammonia and unreacted mono-methylamine, and wherein at least 50% by weight of the ammonia and unreacted mono-methylamine in the at least one intermediate product is removed prior to step (b).
2. The process of claim 1 , wherein x is equal to zero.
3. A process for producing a mixture of amines comprising N,N′-dimethyl-meta-xylylenediamine (DM-MXDA), the process comprising:
(a) contacting 1,3-dicyanobenzene with mono-methylamine in the presence of hydrogen and a catalyst at a hydrogen pressure of about 100 to about 500 psi to form at least one intermediate product;
(b) contacting the at least one intermediate product with hydrogen in the presence of a hydrogenation catalyst at a hydrogen pressure of about 400 to about 1500 psi to form the mixture of amines comprising DM-MXDA; wherein the at least one intermediate product comprises ammonia and unreacted mono-methylamine, and wherein at least 50% by weight of the ammonia and unreacted mono-methylamine in the at least one intermediate product is removed prior to step (b).
4. The process of claim 3 , wherein DM-MXDA is present in the mixture of amines in at least about 60% yield by weight.
5. The process of claim 3 , wherein DM-MXDA is present in the mixture of amines in at least about 70% yield by weight.
6. The process of claim 3 , wherein DM-MXDA is present in the mixture of amines in at least about 80% yield by weight.
7. The process of claim 3 , wherein the mixture of amines further comprises meta-xylylenediamine (MXDA), and wherein MXDA is present in the mixture of amines in less than about 10% yield by weight.
8. The process of claim 3 , wherein the catalyst in step (a) comprises palladium, platinum, rhodium, Raney nickel, or any combination thereof.
9. The process of claim 3 , wherein step (a) is conducted at a temperature of about 70 to about 160 ° C. and at a hydrogen pressure of about 200 to about 450 psi.
10. The process of claim 3 , wherein the hydrogenation catalyst in step (b) comprises palladium, platinum, Raney nickel, Raney cobalt, or any combination thereof.
11. The process of claim 3 , wherein step (b) is conducted at a temperature of about 80 to about 160 ° C. and at a hydrogen pressure of about 750 to about 1000 psi.
12. The process of claim 3 , wherein the catalyst in step (a) and the hydrogenation catalyst in step (b) are the same.
13. The process of claim 1 further comprising contacting the amines of formula (I) with at least one multifunctional epoxy resin.
14. The process of claim 13 further comprising contacting the amines of formula (I) with at least one plasticizer or solvent.