U.S. patent application number 09/728991 was filed with the patent office on 2001-04-12 for curable mixtures based on epoxy resins comprising imidazoles.
Invention is credited to Hall-Goulle, Veronique.
Application Number | 20010000259 09/728991 |
Document ID | / |
Family ID | 4220638 |
Filed Date | 2001-04-12 |
United States Patent
Application |
20010000259 |
Kind Code |
A1 |
Hall-Goulle, Veronique |
April 12, 2001 |
Curable mixtures based on epoxy resins comprising imidazoles
Abstract
Curable mixtures comprising a) an epoxy resin having more than
one 1,2-epoxy group per molecule and b) as curing catalyst, an
imidazole compound of formula I 1 wherein R.sub.1, R.sub.2 and
R.sub.3 are each independently of the others a hydrogen atom, a
halogen atom, alkyl having from 1 to 20 carbon atoms, alkoxy having
from 1 to 20 carbon atoms, unsubstituted or halo-, nitro-,
C.sub.1-4-alkyl- or C.sub.1-4-alkoxy-substituted aralkyl having
from 7 to 20 carbon atoms, or unsubstituted or halo-, nitro-,
C.sub.1-4-alkyl- or C.sub.1-4alkoxy-substituted aryl having from 6
to 20 carbon atoms, and R.sub.4 is alkyl having from 1 to 20 carbon
atoms, alkenyl having from 2 to 20 carbon atoms, alkynyl having
from 2 to 20 carbon atoms, unsubstituted or halo-, nitro-,
C.sub.1-4alkyl- or C.sub.1-4alkoxy-substituted aralkyl having from
7 to 20 carbon atoms or unsubstituted or halo-, nitro-,
C.sub.1-4alkyl- or C.sub.1-4alkoxy-substituted aryl having from 6
to 20 carbon atoms, are suitable for the manufacture of moulding
compounds and coatings, especially for the manufacture of foamed
materials.
Inventors: |
Hall-Goulle, Veronique;
(Reinach, FR) |
Correspondence
Address: |
CIBA SPECIALTY CHEMICALS CORPORATION
PATENT DEPARTMENT
540 WHITE PLAINS RD
P O BOX 2005
TARRYTOWN
NY
10591-9005
US
|
Family ID: |
4220638 |
Appl. No.: |
09/728991 |
Filed: |
December 4, 2000 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
09728991 |
Dec 4, 2000 |
|
|
|
09230410 |
Jan 25, 1999 |
|
|
|
6174985 |
|
|
|
|
09230410 |
Jan 25, 1999 |
|
|
|
PCT/EP97/03811 |
Jul 16, 1997 |
|
|
|
Current U.S.
Class: |
528/117 |
Current CPC
Class: |
C07D 233/54 20130101;
Y10T 428/31511 20150401; Y10T 428/31515 20150401 |
Class at
Publication: |
528/117 |
International
Class: |
C08G 059/40 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 26, 1996 |
CH |
1875/96 |
Claims
What is claimed is:
1. A curable mixture comprising a) an epoxy resin having more than
one 1,2-epoxy group per molecule and b) as curing catalyst, an
imidazole compound of formula I 47 wherein R1, R2 and R3 are each
independently of the others a hydrogen atom, a halogen atom, alkyl
having from 1 to 20 carbon atoms, alkoxy having from 1 to 20 carbon
atoms, unsubstituted or halo-, nitro-, C1-4alkyl- or
C1-4alkoxy-substituted aralkyl having from 7 to 20 carbon atoms, or
unsubstituted or halo-, nitro-, C1-4alkyl- or
C1-4alkoxy-substituted aryl having from 6 to 20 carbon atoms, and
R4 is alkyl having from 1 to 20 carbon atoms, alkenyl having from 2
to 20 carbon atoms, alkynyl having from 2 to 20 carbon atoms,
unsubstituted or halo-, nitro-, C1-4alkyl- or
C1-4alkoxy-substituted aralkyl having from 7 to 20 carbon atoms or
unsubstituted or halo-, C1-4alkyl- or C1-4alkoxy-substituted aryl
having from 6 to 20 carbon atoms.
2. A mixture according to claim 1, comprising as component (a) a
liquid or solid polyglycidyl ether or ester.
3. A mixture according to claim 1, comprising as component (a) a
liquid polyglycidyl ether or ester.
4. A mixture according to claim 1, comprising as component (b) an
imidazole compound of formula I wherein R1 and R2 are each
independently of the other a hydrogen atom, a halogen atom, alkyl
having from 1 to 6 carbon atoms, alkoxy having from 1 to 6 carbon
atoms or phenyl, R3 is a hydrogen atom or phenyl, and R4 is alkyl
having from 1 to 10 carbon atoms, alkenyl having from 2 to 10
carbon atoms, unsubstituted or substituted phenyl or unsubstituted
or substituted benzyl.
5. A mixture according to claim 1, comprising as component (b) an
imidazole compound of formula I wherein each of R.sub.1 and R.sub.3
is a hydrogen atom, R.sub.2 is phenyl, and R.sub.4 is alkenyl
having from 2 to 10 carbon atoms, or unsubstituted or substituted
phenyl or unsubstituted or substituted benzyl, or wherein R.sub.1
is branched alkyl having from 3 to 6 carbon atoms, each of R.sub.2
and R.sub.3 is a hydrogen atom, and R.sub.4 is unsubstituted or
substituted phenyl, unsubstituted or substituted benzyl or branched
alkyl having from 3 to 6 carbon atoms.
6. A mixture according to claim 1, comprising as component (b) an
imidazole compound of the formula 48
7. An imidazole compound of formula II 49wherein X.sub.1, X.sub.2
and X.sub.3 are each independently of the others a hydrogen atom, a
halogen atom, alkyl having from 1 to 20 carbon atoms, alkoxy having
from 1 to 20 carbon atoms, unsubstituted or halo-, nitro-,
C.sub.1-4alkyl- or C.sub.1-4alkoxy-substituted aralkyl having from
7 to 20 carbon atoms, or unsubstituted or halo-, nitro-, C1-4alkyl-
or C1-4alkoxy-substituted aryl having from 6 to 20 carbon atoms,
and X4 is alkenyl having from 10 to 20 carbon atoms or alkynyl
having from 2 to 20 carbon atoms, or wherein each of X1 and X3 is a
hydrogen atom, X2 is unsubstituted or halo-, nitro-, C1-4alkyl- or
C1-4alkoxy-substituted aryl having from 6 to 20 carbon atoms, and
X4 is alkenyl or aryl, or wherein X1 is branched alkyl having from
3 to 6 carbon atoms, each of X2 and X3 is a hydrogen atom, and X4
is aryl or branched alkyl having from 3 to 6 carbon atoms.
8. An imidazole compound according to claim 7, wherein in formula
II each of X1 and X3 is a hydrogen atom, X2 is phenyl, and X4 is
alkenyl having from 2 to 6 carbon atoms or unsubstituted or halo-,
nitro-, C1-4alkyl- or C1-4alkoxy-substituted aryl having from 6 to
20 carbon atoms, or wherein X1 is branched alkyl having from 3 to 6
carbon atoms, each of X2 and X3 is a hydrogen atom, and X4 is
unsubstituted or halo-, nitro-, C1-4alkyl- or
C1-4alkoxy-substituted aryl having from 6 to 20 carbon atoms or
branched alkyl having from 3 to 6 carbon atoms.
9. An imidazole compound according to claim 7, wherein in formula
II X1 is branched alkyl having from 3 to 6 carbon atoms, each of X2
and X3 is a hydrogen atom, and X4 is unsubstituted or halo-,
nitro-, C1-4alkyl- or C1-4alkoxy-substituted phenyl, unsubstituted
or halo-, nitro-, C1-4alkyl- or C1-4alkoxy-substituted benzyl or
branched alkyl having from 3 to 6 carbon atoms.
10. An imidazole compound according to claim 7 of the formula
50
11. A curable mixture comprising a) an epoxy resin having more than
one 1,2-epoxy group per molecule, b1) as curing accelerator, an
imidazole compound of formula I 51 wherein R1, R2 and R3 are each
independently of the others a hydrogen atom, a halogen atom, alkyl
having from 1 to 20 carbon atoms, alkoxy having from 1 to 20 carbon
atoms, unsubstituted or halo-, nitro-, C1-4alkyl- or
C1-4alkoxy-substituted aralkyl having from 7 to 20 carbon atoms, or
unsubstituted or halo-, nitro-, C1-4alkyl- or
C1-4alkoxy-substituted aryl having from 6 to 20 carbon atoms, and
R4 is alkyl having from 1 to 20 carbon atoms, alkenyl having from 2
to 20 carbon atoms, alkynyl having from 2 to 20 carbon atoms,
unsubstituted or halo-, nitro-, C1-4alkyl- or
C1-4alkoxy-substituted aralkyl having from 7 to 20 carbon atoms or
unsubstituted or halo-, C1-4alkyl- or C1-4alkoxy-substituted aryl
having from 6 to 20 carbon atoms, and c) a curing agent for epoxy
resins.
12. A mixture according to claim 11, comprising as component (c)
dicyandiamide or a polycarboxylic acid anhydride.
13. A moulded material, coating or bonded material manufactured by
curing from a curable mixture according to either claim 1 or claim
11.
Description
1. The present invention relates to curable mixtures based on epoxy
resins, which mixtures comprise an epoxy resin having more than one
epoxy group per molecule and substituted imidazole compounds as
curing catalyst or curing accelerator, and also to certain novel
imidazole compounds.
2. The use of unsubstituted or substituted imidazole as a curing
catalyst in the curing of epoxy resins is known. For example, H.
Lee and K. Neville in "Handbook of Epoxy Resins", pages 10-17
(1967), report the property of epoxy resins cured with
2-ethyl-4-methylimidazole.
3. It has, surprisingly, been found that certain substituted
imidazoles in admixture with epoxy resins have an even better
latency at room temperature than mixtures of epoxy resins with
imidazole or with 2-ethyl-4-imidazole, and at elevated temperature
are distinguished by a high reactivity.
4. The present invention accordingly relates to novel curable
mixtures comprising:
5. a) an epoxy resin having more than one 1,2-epoxy group per
molecule and
6. b) as curing catalyst, an imidazole compound of formula I 2
7. wherein
8. R.sub.1, R.sub.2 and R.sub.3 are each independently of the
others a hydrogen atom, a halogen atom, alkyl having from 1 to 20
carbon atoms, alkoxy having from 1 to 20 carbon atoms,
unsubstituted or halo-, nitro-, C.sub.1-4-alkyl- or
C.sub.1-4alkoxy-substituted aralkyl having from 7 to 20 carbon
atoms, or unsubstituted or halo-, nitro-, C.sub.1-4alkyl- or
C.sub.1-4alkoxy-substituted aryl having from 6 to 20 carbon atoms,
and
9. R.sub.4 is alkyl having from 1 to 20 carbon atoms, alkenyl
having from 2 to 20 carbon atoms, alkynyl having from 2 to 20
carbon atoms, unsubstituted or halo-, nitro-, C.sub.1-4alkyl- or
C.sub.1-4-alkoxy-substituted aralkyl having from 7 to 20 carbon
atoms or unsubstituted or halo-, nitro, C.sub.1-4alkyl- or
C.sub.1-4alkoxy-substit- uted aryl having from 6 to 20 carbon
atoms.
10. Suitable epoxy resins (a) for the preparation of the curable
mixtures according to the invention are the epoxy resins
customarily employed in epoxy resin technology. Examples of epoxy
resins are:
11. I) Polyglycidyl and poly(.beta.-methylglycidyl) esters,
obtainable by reaction of a compound having at least two carboxy
groups per molecule with epichlorohydrin or
.beta.-methylepichlorohydrin, respectively. The reaction is
advantageously carried out in the presence of bases. An aliphatic
polycarboxylic acid may be used as compound having at least two
carboxy groups per molecule. Examples of such polycarboxylic acids
are oxalic acid, succinic acid, glutaric acid, adipic acid, pimelic
acid, suberic acid, azelaic acid and dimerised or trimerised
linoleic acid. It is also possible, however, to use cycloaliphatic
polycarboxylic acids, for example tetrahydrophthalic acid,
4-methyltetrahydrophthalic acid, hexahydrophthalic acid or
4-methylhexahydrophthalic acid. Aromatic polycarboxylic acids may
also be used, for example phthalic acid, isophthalic acid or
terephthalic acid.
12. II) Polyglycidyl or poly(.beta.-methylglycidyl) ethers,
obtainable by reaction of a compound having at least two free
alcoholic hydroxy groups and/or phenolic hydroxy groups with
epichlorohydrin or .beta.-methylepichlorohydrin, respectively,
under alkaline conditions, or in the presence of an acid catalyst
with subsequent alkali treatment.
13. Such glycidyl ethers are derived, for example, from acyclic
alcohols, such as from ethylene glycol, diethylene glycol and
higher poly(oxyethylene) glycols, propane-1,2-diol or
poly(oxypropylene) glycols, propane-1,3-diol, butane-1,4-diol,
poly(oxytetramethylene) glycols, pentane-1,5-diol, hexane-1,6-diol,
hexane-2,4,6-triol, glycerol, 1,1,1-trimethylolpropane,
pentaerythritol, sorbitol, and also polyepichlorohydrins. They may
also, however, be derived, for example, from cycloaliphatic
alcohols, for example 1,4-cyclohexanedimethanol,
bis(4-hydroxycyclohexyl)methane or
2,2-bis(4-hydroxycyclohexyl)propane, or they have aromatic nuclei,
such as N,N-bis(2-hydroxy-ethyl)aniline or
p,p'-bis(2-hydroxyethylamino)diphenylmethane.
14. The glycidyl ethers may also be derived from mononuclear
phenols, for example from resorcinol or hydroquinone, or are based
on polynuclear phenols, for example bis(4-hydroxyphenyl)methane,
4,4'-dihydroxybiphenyl, bis(4-hydroxyphenyl)sulfone,
1,1,2,2-tetrakis(4-hydroxyphenyl)ethane,
2,2-bis(4-hydroxyphenyl)propane,
2,2-bis(3,5-dibromo-4-hydroxyphenyl)prop- ane, or from novolaks,
obtainable by condensation of aldehydes, for example formaldehyde,
acetaldehyde, chloral or furfuraldehyde, with phenols, such as
phenol, or with phenols that are substituted in the nucleus by
chlorine atoms or by C.sub.1-C.sub.9alkyl groups, for example
4-chlorophenol, 2-methylphenol or 4-tert-butylphenol, or by
condensation with bisphenols, for example those of the type
mentioned above.
15. III) Poly(N-glycidyl) compounds, obtainable by
dehydrochlorination of the reaction products of epichlorohydrin
with amines that contain at least two amine hydrogen atoms. The
amines are, for example, aniline, n-butylamine,
bis(4-aminophenyl)methane, m-xylylenediamine or
bis(4-methylaminophenyl)methane.
16. The poly(N-glycidyl) compounds, however, also include
triglycidyl isocyanurate, N,N'-diglycidyl derivatives of
cycloalkyleneureas, such as ethyleneurea or 1,3-propyleneurea, and
diglycidyl derivatives of hydantoins, such as
5,5-dimethylhydantoin.
17. IV) Poly(S-glycidyl) compounds, for example di-S-glycidyl
derivatives that are derived from dithiols, for example
ethane-1,2-dithiol or bis(4-mercaptomethylphenyl) ether.
18. V) Cycloaliphatic epoxy resins, for example
bis(2,3-epoxycyclopentyl) ethers, 2,3-epoxycyclopentylglycidyl
ether, 1,2-bis(2,3-epoxycyclopentylo- xy)ethane or
3,4-epoxycyclohexylmethyl-3',4'-epoxycyclohexanecarboxylate.
19. It is also possible, however, to use epoxy resins in which the
1,2-epoxy groups are bonded to different hetero atoms or functional
groups; those compounds include, for example, the N,N,O-triglycidyl
derivative of 4-aminophenol, glycidyl ethers/glycidyl esters of
salicylic acid,
N-glycidyl-N'-(2-glycidyloxypropyl)-5,5-dimethylhydantoin and
2-glycidyloxy-1,3-bis(5,5-dimethyl-1-glycidylhydantoin-3-yl)propane.
20. For the preparation of the epoxy resin compositions according
to the invention it is preferred to use a liquid or solid
polyglycidyl ether or ester, especially a liquid or solid
diglycidyl ether of bisphenol or a solid or liquid diglycidyl ester
of a cycloaliphatic or aromatic dicarboxylic acid, or a
cycloaliphatic epoxy resin. It is also possible to use mixtures of
epoxy resins.
21. Suitable solid polyglycidyl ethers and esters are compounds
having melting points from above room temperature up to
approximately 250.degree. C. Preferably, the melting points of the
solid compounds are in the range from 50 to 150.degree. C. Such
solid compounds are known and some of them are available
commercially. As solid polyglycidyl ethers and esters it is also
possible to use the advancement products obtained by pre-extension
of liquid polyglycidyl ethers and esters.
22. The epoxy resin compositions according to the invention
especially comprise a liquid polyglycidyl ether or ester.
23. The curable mixtures according to the invention comprise as
component (b) preferably imidazole compounds of formula I
wherein
24. R.sub.1 and R.sub.2 are each independently of the other a
hydrogen atom, a halogen atom, alkyl having from 1 to 6 carbon
atoms, alkoxy having from 1 to 6 carbon atoms or phenyl,
25. R.sub.3 is a hydrogen atom or phenyl, and
26. R.sub.4 is alkyl having from 1 to 10 carbon atoms, alkenyl
having from 2 to 10 carbon atoms, unsubstituted or substituted
phenyl or unsubstituted or substituted benzyl.
27. Suitable single or multiple substituents of phenyl or of benzyl
are halogen atoms and nitro, C.sub.1-C.sub.4alkyl- and
C.sub.1-C.sub.4alkoxy groups.
28. The mixtures according to the invention especially comprise as
component (b) an imidazole compound of formula I wherein
29. each of R.sub.1 and R.sub.3 is a hydrogen atom,
30. R.sub.2 is phenyl, and
31. R.sub.4 is alkenyl having from 2 to 10 carbon atoms, or
unsubstituted or substituted phenyl or unsubstituted or substituted
benzyl,
32. or wherein
33. R.sub.1 is branched alkyl having from 3 to 6 carbon atoms,
34. each of R.sub.2 and R.sub.3 is a hydrogen atom, and
35. R.sub.4 is unsubstituted or substituted phenyl, unsubstituted
or substituted benzyl or branched alkyl having from 3 to 6 carbon
atoms.
36. In an especially preferred embodiment, the mixtures according
to the invention comprise an imidazole compound of the formula
3
37. In the curable mixtures according to the invention, the
proportion of component (b) is generally from 0.1 to 20% by weight,
preferably from 1 to 15% by weight, based on the amount of
component (a).
38. Some of the compounds of formula I are known compounds, which
are described, for example, in U.S. Pat. No. 4,189,543 and can be
prepared by reacting
39. 1.) 1 mol of an imidazole compound of the formula 4
40. wherein R.sub.1, R.sub.2 and R.sub.3 are as defined for formula
I, with 1 mol of a chloroformic acid ester of the formula 5
41. wherein R.sub.4 is as defined for formula I, or
42. 2.) 1 mol of an imidazole compound of the formula 6
43. wherein R.sub.1, R.sub.2 and R.sub.3 are as defined for formula
I, with 1 mol of a dicarbonate of the formula 7
44. wherein R.sub.4 is as defined for formula I, or
45. 3.) 1 mol of a carbonyldiimidazole compound of the formula
8
46. wherein R.sub.1, R.sub.2 and R.sub.3 are as defined for formula
I, with 1 mol of an alcohol of the formula R.sub.4--OH, wherein
R.sub.4 is as defined for formula I,
47. to form compounds of formula I.
48. Insofar as the compounds of formula I are novel compounds,
protection is also claimed for those compounds.
49. The present invention accordingly relates also to novel
imidazole compounds of formula II 9
50. wherein
51. X.sub.1, X.sub.2 and X.sub.3 are each independently of the
others a hydrogen atom, a halogen atom, alkyl having from 1 to 20
carbon atoms, alkoxy having from 1 to 20 carbon atoms,
unsubstituted or halo-, nitro-, C.sub.1-4alkyl- or
C.sub.1-4alkoxy-substituted aralkyl having from 7 to 20 carbon
atoms, or unsubstituted or halo-, nitro-, C.sub.1-4alkyl- or
C.sub.1-4alkoxy-substituted aryl having from 6 to 20 carbon atoms,
and
52. X.sub.4 is alkenyl having from 10 to 20 carbon atoms or alkenyl
having from 2 to 20 carbon atoms, or wherein
53. each of X.sub.1 and X.sub.3 is a hydrogen atom,
54. X.sub.2 is unsubstituted or halo-, nitro-, C.sub.1-4alkyl- or
C.sub.1-4alkoxy-substituted aryl having from 6 to 20 carbon atoms,
and
55. X.sub.4 is alkenyl or aryl,
56. or wherein
57. X.sub.1 is branched alkyl having from 2 to 6 carbon atoms,
58. each of X.sub.2 and X.sub.3 is a hydrogen atom, and
59. X.sub.4 is aryl or branched alkyl having from 2 to 6 carbon
atoms.
60. In formula II, preferably
61. each of X.sub.1 and X.sub.3 is a hydrogen atom,
62. X.sub.2 is phenyl, and
63. X.sub.4 is alkenyl having from 2 to 6 carbon atoms or
unsubstituted or halo-, nitro-, C.sub.1-4alkyl- or
C.sub.1-4alkoxy-substituted aryl having from 6 to 20 carbon atoms,
or
64. X.sub.1 is branched alkyl having from 3 to 6 carbon atoms,
65. each of X.sub.2 and X.sub.3 is a hydrogen atom, and
66. X.sub.4 is unsubstituted or halo-, nitro-, C.sub.1-4alkyl- or
C.sub.1-4alkoxy-substituted aryl having from 6 to 20 carbon atoms
or branched alkyl having from 2 to 6 carbon atoms.
67. In formula II, especially
68. X.sub.1 is branched alkyl having from 3 to 6 carbon atoms
69. each of X.sub.2 and X.sub.3 is a hydrogen atom, and
70. X.sub.4 is unsubstituted or halo-, nitro-, C.sub.1-4alkyl- or
C.sub.1-4alkoxy-substituted phenyl, unsubstituted or halo-, nitro-,
C.sub.1-4alkyl- or C.sub.1-4alkoxy-substituted benzyl or branched
alkyl having from 3 to 6 carbon atoms.
71. Especially preferred are the imidazole compounds of the
formulae 10
72. The compounds of formula II may also be prepared in accordance
with the three above-mentioned processes using the appropriate
starting materials.
73. As mentioned at the outset, the imidazole compounds of formulae
I and II are also suitable as curing accelerators in mixtures
comprising epoxy resin and curing agent.
74. The present invention accordingly relates also to curable
mixtures comprising
75. a) an epoxy compound having more than one 1,2-epoxy group per
molecule,
76. b1) as curing accelerator, an imidazole compound of formula I
11
77. wherein
78. R.sub.1, R.sub.2 and R.sub.3 are each independently of the
others a hydrogen atom, a halogen atom, alkyl having from 1 to 20
carbon atoms, alkoxy having from 1 to 20 carbon atoms,
unsubstituted or halo-, nitro-, C.sub.1-4alkyl- or
C.sub.1-4alkoxy-substituted aralkyl having from 7 to 20 carbon
atoms, or unsubstituted or halo-, nitro-, C.sub.1-4alkyl- or
C.sub.1-4alkoxy-substituted aryl having from 6 to 20 carbon atoms,
and
79. R.sub.4 is alkyl having from 1 to 20 carbon atoms, alkenyl
having from 2 to 20 carbon atoms, alkynyl having from 2 to 20
carbon atoms, unsubstituted or halo-, nitro-, C.sub.1-4alkyl- or
C.sub.1-4alkoxy-substituted aralkyl having from 7 to 20 carbon
atoms or unsubstituted or halo-, nitro-, C.sub.1-4alkyl- or
C.sub.1-4alkoxy-substituted aryl having from 6 to 20 carbon atoms,
and
80. c) a curing agent for epoxy resins.
81. As curing accelerator it is preferred to use the same imidazole
compounds of formula I preferably used as curing catalyst. There is
also used as curing accelerator generally from 0.1 to 20% by weight
of imidazole compound of formula I, based on the amount of
component (a).
82. The curable mixtures according to the invention may comprise as
curing agent (c) a curing agent customarily employed in epoxy resin
technology, for example dicyandiamide, polycarboxylic acids and
anhydrides thereof, polyamines, polyaminoamides, amino
group-containing adducts, aliphatic or aromatic polyols or
catalytically active curing agents.
83. The mixtures according to the invention preferably comprise as
curing agent dicyandiamide, a polycarboxylic acid or an anhydride
thereof.
84. There may be mentioned as suitable polycarboxylic acids, for
example, aliphatic polycarboxylic acids, for example maleic acid,
oxalic acid, succinic acid, nonyl- or dodecylsuccinic acid,
glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic
acid and dimerised or trimerised linoleic acid, cycloaliphatic
polycarboxylic acids, for example tetrahydrophthalic acid,
methylendomethylenetetrahydrophthalic acid,
hexachloroendomethylenetetrahydrophthalic acid,
4-methyltetrahydrophthalic acid, hexahydrophthalic acid and
4-methylhexahydrophthalic acid, and aromatic polycarboxylic acids,
for example phthalic acid, isophthalic acid, terephthalic acid,
trimellitic acid, pyromellitic acid and
benzophenone-3,3',4,4'-tetracarboxylic acid, and the anhydrides of
the mentioned polycarboxylic acids.
85. The amount of curing agent used depends upon the chemical
nature of the curing agent and upon the desired properties of the
curable mixture and of the cured product. The maximum amount can be
determined readily. When the curing agent is an amine, usually from
0.75 to 1.25 equivalents of amine hydrogen are used per equivalent
of epoxide. When polycarboxylic acids or anhydrides thereof are
used, usually from 0.4 to 1.1 equivalents of carboxy group or
anhydride group, respectively, are used per equivalent of epoxide.
When polyphenols are used as curing agent, from 0.75 to 1.25
phenolic hydroxy groups are used per equivalent of epoxide.
Catalytically active curing agents are generally used in amounts of
from 1 to 40 parts by weight per 100 parts by weight of epoxy
resin.
86. The curable mixtures according to the invention may also
comprise the fillers and reinforcing materials customarily employed
in epoxy resin technology. Suitable fillers include, for example:
mineral and fibrous fillers, such as quartz powder, fused silica,
aluminium oxide, glass powder, mica, kaolin, dolomite, graphite,
carbon black, and also carbon fibres and textile fibres. Preferred
fillers are quartz powder, fused silica, aluminium oxide and
dolomite. Suitable reinforcing materials are, for example, glass
fibres or carbon fibres.
87. The curable mixtures according to the invention are prepared
according to methods known per se, for example using known mixing
apparatus, for example stirrers, kneaders, rollers or, in the case
of solid substances, dry mixers.
88. The curing of the curable mixtures according to the invention
to form mouldings, coatings or the like is carried out in a manner
customarily employed in epoxy resin technology, as described, for
example, in "Handbook of Epoxy Resins", 1967, by H. Lee and K.
Neville.
89. The curable mixtures according to the invention are excellently
suitable as casting resins, laminating resins, adhesives,
compression moulding compounds, foamed materials, coating compounds
and also as encasing systems for electrical and electronic
components, especially as laminating resins or foamed
materials.
90. The present invention accordingly relates also to the moulded
materials, coatings or bonded materials manufactured from the
curable mixtures according to the invention.
91. The following Examples describe the preparation of compounds of
formulae I and II; the yields of the compounds have not been
optimised.
EXAMPLE A1
92. 9.45 g (0.1 mol) of chloroformic acid methyl ester are added
dropwise in portions to a solution, cooled to from 0 to 5.degree.
C. using an ice-water bath, of 13.6 g (0.2 mol) of imidazole in 200
ml of tetrahydrofuran, the portions being such that the temperature
of the reaction solution remains below 5.degree. C. Once the
addition is complete, the ice-water bath is removed so that the
reaction solution can warm up to room temperature. The white
precipitate is filtered off, and the filtrate is concentrated to
dryness by evaporation to yield 11.8 g (94% of the theoretical
yield) of the compound of the formula 12
93. having a melting point of 41.8.degree. C.
1 Elemental analysis: found calculated 47.27% C 47.62% C 4.83% H
4.80% H 22.14% N 22.21% N.
EXAMPLE A2
94. 10.85 g (0.1 mol) of chloroformic acid ethyl ester are added
dropwise in portions, with stirring, to a mixture, cooled to below
5.degree. C. using an ice-water bath, of 6.80 g (0.1 mol) of
imidazole and 11.1 g (0.11 mol) of triethylamine in 100 ml of
acetonitrile, the portions being such that the temperature of the
reaction mixture remains below 5.degree. C. The reaction mixture is
then stirred at that temperature for a further hour. The reaction
mixture is then allowed to warm up to room temperature, and the
resulting white precipitate is filtered off and washed with
acetonitrile. The filtrate is concentrated to dryness by
evaporation, and the residue is taken up in dichloromethane. The
organic phase is washed three times with water and then dried over
Na.sub.2SO.sub.4. After filtration, the organic phase is
concentrated to dryness by evaporation in vacuo to yield 11.6 g
(82% of the theoretical yield) of the compound of the formula
13
95. in the form of a colourless liquid.
2 Elemental analysis: found calculated 51.16% C 51.42% C 5.78% H
5.75% H 19.70% N 19.99% N.
EXAMPLE A3
96. The compound of the formula 14
97. is available commercially (Lancaster).
98. Melting point: 46-47.degree. C.
EXAMPLE A4
99. The process set out in Example 2 is repeated using chloroformic
acid n-butyl ester instead of chloroformic acid ethyl ester to
yield the compound of the formula 15
100. Yield: 85% of the theoretical yield.
3 Elemental analysis: found calculated 56.89% C 57.13% C 7.24% H
7.19% H 16.49% N 16.66% N.
EXAMPLE A5
101. The process set out in Example 2 is repeated using
chloroformic acid n-octyl ester instead of chloroformic acid ethyl
ester to yield the compound of the formula 16
102. having a melting point of 39.1.degree. C.
103. Yield: 98% of the theoretical yield.
EXAMPLE A6
104. A mixture of 4 g (25 mmol) of N,N'-carbonyldiimidazole and 6.3
g of 1-heptadecanol in 100 ml of tetrahydrofuran is stirred
overnight at room temperature. After removal of the solvent by
evaporation, the solid residue is triturated in hexane and
insoluble residue is removed by filtration. The filtrate is
concentrated to dryness by evaporation to yield 8.0 g (92% of the
theoretical yield) of a solid white crystalline substance having a
melting point of 59.3.degree. C. that corresponds to the formula
17
4 Elemental analysis: found calculated 72.69% C 71.95% C 11.11% H
10.93% H 7.23% N 7.99% N.
105. The .sup.1H NMR spectrum of the prepared compound corresponds
to the formula given above.
EXAMPLE A7
106. 3.96 g (29.4 mmol) of chloroformic acid buten-3-yl ester are
added dropwise, with stirring, to a mixture, maintained at below
5.degree. C. using an ice-water bath, of 2 g (29.4 mmol) of
imidazole and 3.27 g (32.3 mmol) of triethylamine in 50 ml of
acetonitrile, in such amounts that the reaction temperature remains
below 5.degree. C. Overnight the reaction mixture is stirred
further at room temperature, and then the white precipitate is
filtered off and washed with acetonitrile. The filtrate is
concentrated to dryness, the residue is dissolved in
dichloromethane, and the organic phase is washed three times with
water. The organic phase is then dried over Na.sub.2SO.sub.4,
filtered, and concentrated by evaporation in vacuo at 40.degree. C.
4.4 g (90% of the theoretical yield) of a pale-yellow liquid are
obtained that corresponds to the formula 18
5 Elemental analysis: found calculated 57.60% C 57.82% C 6.11% H
6.07% H 16.72% N 16.86% N.
107. The .sup.1H NMR spectrum of the prepared compound corresponds
to the formula given above.
EXAMPLE A8
108. A mixture of 4 g (25 mmol) of N,N'-carbonyldiimidazole and
2.12 g (25 mmol) of 2-methyl-3-buten-2-ol in 50 ml of
dichloromethane is stirred overnight at room temperature. After
removal of the solvent by evaporation, the solid residue is
triturated in 10 ml of hexane and filtered to remove insoluble
residue which is washed with 40 ml of hexane. The filtrate is
concentrated to dryness by evaporation yielding 2.64 g of the crude
imidazole compound which is separated off by chromatography over 60
g of silica gel using ethyl acetate as eluant, the first 10
fractions being concentrated by evaporation to yield 1.74 g (39% of
the theoretical yield) of the pure compound of the formula 19
6 Elemental analysis: found calculated 59.95% C 60.00% C 6.85% H
6.67% H 15.33% N 15.55% N.
109. The .sup.1H NMR spectrum of the prepared compound corresponds
to the formula given above.
EXAMPLE A9
110. In accordance with the process given in Polymer Journal, Vol.
26, No. 7, pages 864-867, 5.35 g (35 mmol) of
N,N'-carbonyldiimidazole and 5.7 g (35 mmol) of 2-nitrobenzyl
alcohol in 140 ml of acetonitrile are stirred overnight at room
temperature. After filtering off the precipitate, the filtrate is
concentrated to dryness by evaporation to yield 4.6 g (68.5% of the
theoretical yield) of a compound of the formula 20
111. having a melting point of 141.3.degree. C.
7 Elemental analysis: found calculated 53.38% C 53.44% C 3.77% H
3.67% H 16.98% N 17.00% N.
EXAMPLE A10
112. 3.00 g (10.7 mmol) of chloroformic acid 6-nitroveratryl ester
are added in portions, with stirring, to a mixture, maintained at
below 3.degree. C. using an ice-water bath, of 0.74 g (10.7 mmol)
of imidazole and 1.21 g (11.9 mmol) of triethylamine in 100 ml of
acetonitrile, the portions being such that the reaction temperature
remains below 10.degree. C. Overnight the mixture is stirred
further at room temperature, and then the white precipitate is
filtered off and washed with acetonitrile. The filtrate is
concentrated to dryness, the residue is dissolved in
dichloromethane and the organic phase is washed three times with
water. The organic phase is dried over Na.sub.2SO.sub.4, filtered
and concentrated by evaporation. The crude product is
recrystallised from xylene to yield 2.71 g (81% of the theoretical
yield) of slightly orange-coloured needles that correspond to the
formula 21
113. and have a melting point of 136.1.degree. C.
8 Elemental analysis: found calculated 51.17% C 50.82% C 4.60% H
4.26% H 13.23% N 13.68% N
114. The .sup.1H NMR spectrum of the prepared compound corresponds
to the formula given above.
EXAMPLE A11
115. 5.42 g (50 mmol) of chloroformic acid ethyl ester are added
dropwise in portions, with stirring, to a solution, maintained at
below 3.degree. C. using an ice-water bath, of 7.2 g (50 mmol) of
4-phenylimidazole and 5.56 g (55 mmol) of triethylamine in a
solvent mixture of 50 ml of acetonitrile and 40 ml of
dichloromethane, the portions being such that the temperature of
the reaction solution remains below 5.degree. C. After further
stirring at that temperature for 30 minutes, the ice-water bath is
removed, and the reaction solution warms up to room temperature.
The beige precipitate is filtered off, and dichloromethane is added
to the filtrate. The organic phase is washed three times with water
and dried over Na.sub.2SO.sub.4. After filtration, the organic
phase is concentrated to dryness by evaporation. The resulting
crude product is recrystallised from cyclohexane to yield 9.7 g
(90% of the theoretical yield) of the pure compound of the formula
22
116. The white crystals have a melting point of 110.9.degree.
C.
9 Elemental analysis: found calculated 66.63% C 66.65% C 5.78% H
5.59% H 12.99% N 12.96% N.
117. The .sup.1H NMR spectrum of the prepared compound corresponds
to the formula given above.
EXAMPLE A12
118. 1.9 g (13.9 mmol) of chloroformic acid n-butyl ester are added
dropwise in portions, with stirring, to a solution, maintained at
below 4.degree. C. using an ice-water bath, of 2.0 g (13.9 mmol) of
4-phenylimidazole and 1.55 g (15.3 mmol) of triethylamine in a
solvent mixture of 70 ml of acetonitrile, 50 ml of ether and 120 ml
of tert-butyl methyl ether, the portions being such that the
temperature of the reaction solution remains below 5.degree. C.
After further stirring at that temperature for 1 hour, the
ice-water bath is removed, and the reaction solution is allowed to
warm up to room temperature. The white precipitate is filtered off,
and the filtrate is concentrated to dryness by evaporation. The
crude product is purified by chromatography over silica gel using
dichloromethane/ethyl acetate (30:1) as eluant. The first three
fractions (75 ml) are concentrated to dryness by evaporation to
yield 2.8 g (83% of the theoretical yield) of a pure compound of
the formula 23
119. The white crystals have a melting point of 116.9.degree.
C.
10 Elemental analysis: found calculated 68.64% C 68.83% C 6.77% H
6.60% H 11.35% N 11.47% N.
120. The .sup.1H NMR spectrum of the prepared compound corresponds
to the formula given above.
EXAMPLE A13
121. 2.69 g (20 mmol) of chloroformic acid buten-3-yl ester are
added dropwise in portions, with stirring, to a solution,
maintained at below 3.degree. C. using an ice-water bath, of 2.88 g
(20 mmol) of 4-phenylimidazole and 2.22 g (22 mmol) of
triethylamine in 100 ml of acetonitrile, the portions being such
that the temperature of the reaction solution remains below
5.degree. C. The ice-water bath is removed, and the reaction
solution is allowed to warm up to room temperature and is stirred
further overnight. The white precipitate is filtered off, and the
filtrate is concentrated to dryness by evaporation. The residue is
dissolved in dichloromethane and washed three times with water. The
organic phase is dried over Na.sub.2SO.sub.4, filtered and
concentrated to dryness by evaporation. The residue is triturated
in 100 ml of hexane, filtered to remove insoluble material, and the
filtrate is dried in a vacuum oven. 3.67 g (76% of the theoretical
yield) of a pure compound of the formula 24
122. are obtained in the form of a white substance that melts at
79.3.degree. C.
11 Elemental analysis: found calculated 69.33% C 69.34% C 5.81% H
5.78% H 11.56% N 11.56% N.
123. The .sup.1H NMR spectrum of the prepared compound corresponds
to the formula given above.
EXAMPLE A14
124. 1.5 g (8.8 mmol) of chloroformic acid benzyl ester are added
dropwise in portions, with stirring, to a suspension, maintained at
below 5.degree. C. using an ice-water bath, of 1.0 g (8.8 mmol) of
4-phenylimidazole in a solvent mixture of 15 ml of acetonitrile and
3 ml of dichloromethane, the portions being such that the
temperature of the reaction solution remains below 5.degree. C. The
reaction solution is stirred at that temperature for a further hour
and then the ice-water bath is removed, and the reaction solution
is allowed to warm up to room temperature and is then stirred for a
further 45 minutes. After removal of the solvent and after the
addition of water, the product is extracted using dichloromethane.
The organic phase is washed three times with water and dried over
Na.sub.2SO.sub.4, filtered and concentrated to dryness by
evaporation. The residue is triturated in 100 ml of hexane and
filtered to remove insoluble material, and the filtrate is dried in
a vacuum oven. 1.53 g of a crude product are obtained, which are
recrystallised from a solvent mixture of dichloromethane and
hexane. 1.21 g (56% of the theoretical yield) of a pure compound of
the formula 25
125. are obtained in the form of a white flocculent substance that
melts at 93.7.degree. C.
12 Elemental analysis: found calculated 73.33% C 73.37% C 5.23% H
5.07% H 9.88% N 10.07% N.
126. The .sup.1H NMR spectrum of the prepared compound corresponds
to the formula given above.
EXAMPLE A15
127. 1.37 g (8.8 mmol) of chloroformic acid phenyl ester are added
dropwise in portions, with stirring, to a suspension of 1.0 g (8.8
mmol) of 4-phenylimidazole and 1.0 g (9.6 mmol) of triethylamine in
a solvent mixture consisting of 15 ml of acetonitrile and 5 ml of
dichloromethane, the portions being such that the temperature of
the reaction solution remains below 20.degree. C. The reaction
solution is then stirred at room temperature for a further hour,
the white precipitate is filtered off and the filtrate is
concentrated to dryness by evaporation. Water is added to the
residue and extraction is carried out in dichloromethane. The
organic phase is washed several times with water, filtered, dried
over Na.sub.2SO.sub.4 and concentrated to dryness by evaporation.
1.9 g (93% of the theoretical yield) of a pure compound of the
formula 26
128. are obtained in the form of a white powder that melts at
138.1.degree. C.
13 Elemental analysis: found calculated 72.48% C 72.72% C 4.58% H
4.58% H 10.70% N 10.60% N.
129. The .sup.1H NMR spectrum of the prepared compound corresponds
to the formula given above.
EXAMPLE A16
130. 5.32 g (50 mmol) of chloroformic acid vinyl ester are added
dropwise in portions, with stirring, to a suspension, maintained at
below 4.degree. C. using an ice-water bath, of 7.21 g (50 mmol) of
4-phenylimidazole and 5.56 g (55 mmol) of triethylamine in a
solvent mixture of 170 ml of acetonitrile and 300 ml of tert-butyl
methyl ether, the portions being such that the temperature of the
reaction solution remains below 5.degree. C. The ice-water bath is
removed, and the reaction solution is allowed to warm up to room
temperature and is then stirred at room temperature for a further
24 hours. The white precipitate is filtered off, and the filtrate
is washed several times with water. The organic phase is dried over
Na.sub.2SO.sub.4, filtered and concentrated to dryness by
evaporation. 6.16 g (58% of the theoretical yield) of a pure
compound of the formula 27
131. are obtained in the form of colourless needles having a
melting point of 128.1.degree. C.
14 Elemental analysis: found calculated 67.25% C 67.28% C 4.78% H
4.71% H 13.06% N 13.08% N.
132. The .sup.1H NMR spectrum of the compound obtained corresponds
to the formula given above.
EXAMPLE A17
133. 10.78 g (50 mmol) of chloroformic acid 4-nitrobenzyl ester are
added dropwise in portions, with stirring, to a solution,
maintained at below 3.degree. C. using an ice bath, of 7.21 g (50
mmol) of 4-phenylimidazole and 5.57 g (55 mmol) of triethylamine in
500 ml of tert-butyl methyl ether, the portions being such that the
temperature of the reaction solution remains below 3.degree. C. The
ice bath is removed, and the reaction solution is allowed to warm
up to room temperature and is then stirred further overnight. The
white precipitate is filtered off and the filtrate is washed five
times with water and dried over Na.sub.2SO.sub.4. The slightly
yellow solid substance obtained after concentration to dryness by
evaporation is recrystallised from toluene. 1.01 g (6% of the
theoretical yield) of a pure compound of the formula 28
134. are obtained having a melting point of 155.0.degree. C.
15 Elemental analysis: found calculated 63.29% C 63.15% C 4.47% H
4.36% H 12.83% N 12.99% N.
135. The .sup.1H NMR spectrum of the compound obtained corresponds
to the formula given above.
EXAMPLE A18
136. 1.94 g (7 mmol) of chloroformic acid 6-nitroveratryl ester are
added in portions, with stirring, to a solution, maintained at
below 4.degree. C. using an ice-water bath, of 1.01 g (7 mmol) of
4-phenylimidazole and 0.78 g (7 mmol) of triethylamine in 90 ml of
acetonitrile, the portions being such that the temperature of the
reaction solution remains below 5.degree. C. The ice-water bath is
removed, and the reaction solution is allowed to warm up to room
temperature and is then stirred at room temperature for a further 2
hours. After filtration of the resulting yellow suspension, the
solvent is evaporated off from the filtrate, and the residue is
dissolved in 100 ml of dichloromethane. The organic phase is washed
three times with water, dried over Na.sub.2SO.sub.4 and
concentrated to dryness by evaporation. 2.27 g (84% of the
theoretical yield) of a pure compound of the formula 29
137. are obtained in the form of a solid yellow substance having a
melting point of 188.3.degree. C.
16 Elemental analysis: found calculated 59.51% C 59.47% C 4.51% H
4.43% H 10.94% N 10.96% N.
138. The .sup.1H NMR spectrum of the compound obtained corresponds
to the formula given above.
EXAMPLE A19
139. The process set out in Example 2 is repeated using
2-phenylimidazole instead of imidazole, and a compound of the
formula 30
140. is obtained.
141. Yield: 21% of the theoretical yield.
17 Elemental analysis: found calculated 66.59% C 66.65% C 5.67% H
5.59% H 12.95% N 12.96% N.
EXAMPLE A20
142. 156.5 g (1 mol) of chloroformic acid phenyl ester are added
dropwise in portions to a stirred solution of 188.18 g (1 mol) of
2-phenylimidazole and 1111.31 g (1.1 mol) of triethylamine in a
solvent mixture of 1 liter of acetonitrile and 1.3 liters of
dichloromethane, the portions being such that the temperature of
the reaction solution, cooled using an ice-water bath, remains
between 15.degree. C. and 20.degree. C. The reaction solution is
then stirred at room temperature for a further 48 hours. After
filtration of the precipitate, the solvent is evaporated off from
the filtrate, and the residue is dissolved in dichloromethane. The
organic phase is washed three times with water, dried over
Na.sub.2SO.sub.4 and concentrated to dryness by evaporation. 257.6
g of a crude product that still contains small amounts of unreacted
2-phenylimidazole are obtained. The crude product is recrystallised
from tert-butyl methyl ether to yield 131.1 g (49% of the
theoretical yield) of a pure compound of the formula 31
143. in the form of colourless needles that melt at 188.3.degree.
C.
18 Elemental analysis: found calculated 72.61% C 72.72% C 4.71% H
4.58% H 10.65% N 10.60% N.
144. The .sup.1H NMR spectrum of the compound obtained corresponds
to the formula given above.
EXAMPLE A21
145. 119.3 g (1.1 mol) of chloroformic acid ethyl ester are added
dropwise in portions, with stirring, to a suspension, maintained at
below 3.degree. C. using an ice-water bath, of 158.2 g (1 mol) of
4-methyl-2-phenylimidazole and 112.1 g (1.1 mol) of triethylamine
in 4 liters of tetrahydrofuran, the portions being such that the
temperature of the reaction solution remains below 5.degree. C. The
ice-water bath is removed, and the reaction solution is allowed to
warm up to room temperature and is then stirred at room temperature
overnight. The white precipitate is filtered off, and the filtrate
is concentrated to dryness. The residue is taken up in 1 liter of
dichloromethane, and the organic phase is washed three times with
water and then dried over Na.sub.2SO.sub.4, filtered and
concentrated to dryness by evaporation. The residue is triturated
in hexane and filtered, and the filtrate is concentrated to dryness
again, yielding a red-orange liquid which is purified by
chromatography over silica gel using a solvent mixture of 7 parts
of ethylacetate and 3 parts of acetonitrile as eluant. Evaporation
of the fractions 8 to 21 (150 ml) yields 119.6 g (52% of the
theoretical yield) of a pure compound of the formula 32
146. in the form of an orange liquid.
19 Elemental analysis: found calculated 67.73% C 67.81% C 6.28% H
6.13% H 12.17% N 12.17% N.
147. The .sup.1H NMR spectrum of the compound obtained corresponds
to the structural formula given above.
EXAMPLE A22
148. The process set out in Example 2 is repeated using
2-ethyl-4-methylimidazole instead of imidazole and a compound of
the formula 33
149. is obtained.
150. Yield: 77% of the theoretical yield.
20 Elemental analysis: found calculated 58.93% C 59.32% C 7.86% H
7.74% H 15.30% N 15.37% N.
EXAMPLE A23
151. 15.65 g (0.1 mol) of chloroformic acid phenyl ester are added
dropwise in portions, with stirring, to a solution, maintained at
below 2.degree. C. using an ice-water bath, of 11.0 g (0.1 mol) of
2-ethyl-4-methylimidazole and 11.13 g (0.11 mol) of triethylamine
in 100 ml of acetonitrile, the portions being such that the
temperature of the reaction solution remains below 5.degree. C. The
ice-water bath is removed, and the reaction solution is allowed to
warm up to room temperature and is then stirred at room temperature
for a further 1.5 hours. The precipitate is filtered off and washed
with dichloromethane, and the substance is isolated from the
filtrate by extraction. The organic phase is washed three times
with water, dried over Na.sub.2SO.sub.4 and concentrated to dryness
by evaporation. A yellow solid substance is obtained, which is
recrystallised from hexane to yield 17.2 g (75% of the theoretical
yield) of a pure compound of the formula 34
152. in the form of slightly yellow needles having a melting point
of 188.3.degree. C.
21 Elemental analysis: found calculated 67.63% C 67.81% C 6.21% H
6.13% H 12.21% N 12.17% N.
153. The .sup.1H NMR spectrum of the compound obtained corresponds
to the formula given above.
EXAMPLE A24
154. 170.6 g (1 mol) of chloroformic acid benzyl ester are added
dropwise in portions, with stirring, to a solution, maintained at
below 3.degree. C. using an ice-water bath, of 110.16 g (1 mol) of
2-ethyl-4-methylimidazole and 111.3 g (1.1 mol) of triethylamine in
1.5 liters of acetonitrile, the portions being such that the
temperature of the reaction solution remains below 5.degree. C. The
ice-water bath is removed, and the reaction solution is allowed to
warm up to room temperature and is then stirred at room temperature
for a further 3 hours. The precipitate is filtered off, and the
filtrate is extracted with tert-butyl methyl ether. The organic
phase is washed three times with water, dried over
Na.sub.2SO.sub.4, filtered and concentrated to dryness by
evaporation. 200.63 g of crude product are obtained, which are
purified by chromatography over silica gel using ethyl
acetate/acetonitrile (9:1) as eluant to yield 145.47 g (60% of the
theoretical yield) of a pure compound of the formula 35
155. in the form of a colourless liquid.
22 Elemental analysis: found calculated 68.84% C 68.83% C 6.49% H
6.60% H 11.38% N 11.47% N.
156. The .sup.1H NMR spectrum of the compound obtained corresponds
to the formula given above.
EXAMPLE A25
157. 5.32 g (50 mmol) of chloroformic acid vinyl ester are added
dropwise in portions, with stirring, to a solution, maintained at
below 2.degree. C. using an ice-water bath, of 5.51 g (50 mmol) of
2-ethyl-4-methylimidazole and 5.56 g (55 mmol) of triethylamine in
70 ml of acetonitrile, the portions being such that the temperature
of the reaction solution remains below 5.degree. C. The ice-water
bath is removed, and the reaction solution is allowed to warm up to
room temperature and is then stirred at room temperature for a
further hour. The precipitate is filtered off, and the filtrate is
extracted with tert-butyl methyl ether. The organic phase is washed
five times with water, dried over Na.sub.2SO.sub.4, filtered and
concentrated to dryness by evaporation to yield 8.36 g (93% of the
theoretical yield) of a pure compound of the formula 36
158. in the form of a colourless liquid.
23 Elemental analysis: found calculated 59.47% C 59.99% C 7.11% H
6.71% H 14.89% N 15.55% N.
159. The .sup.1H NMR spectrum of the compound obtained corresponds
to the formula given above.
EXAMPLE A26
160. 10.78 g (50 mmol) of chloroformic acid 4-nitrobenzyl ester are
added dropwise in portions, with stirring, to a solution,
maintained at below 5.degree. C. using an ice-water bath, of 5.51 g
(50 mmol) of 2-ethyl-4-methylimidazole and 5.56 g (55 mmol) of
triethylamine in 70 ml of acetonitrile, the portions being such
that the temperature of the reaction solution remains below
5.degree. C. The ice-water bath is removed, and the reaction
solution is allowed to warm up to room temperature and is stirred
at room temperature overnight. The precipitate formed is filtered
off, and the filtrate is extracted with tert-butyl methyl ether.
The organic phase is washed five times with water, dried over
Na.sub.2SO.sub.4, filtered and concentrated to dryness by
evaporation. A slightly yellow solid substance is obtained, which
is recrystallised from tert-butyl methyl ether to yield 9.32 g (64%
of the theoretical yield) of a pure compound of the formula 37
161. in the form of colourless crystals that melt at 106.1.degree.
C.
24 Elemental analysis: found calculated 58.11% C 58.13% C 5.22% H
5.23% H 14.59% N 14.53% N.
162. The .sup.1H NMR spectrum of the compound obtained corresponds
to the formula given above.
EXAMPLE A27
163. 0.50 g (1.8 mmol) of chloroformic acid 6-nitroveratryl ester
is added dropwise in portions, with stirring, to a solution,
maintained at below 2.degree. C. using an ice-water bath, of 0.2 g
(1.8 mmol) of 2-ethylimidazole and 0.20 g (2 mmol) of triethylamine
in a solvent mixture of 25 ml of acetonitrile and 30 ml of
tert-butyl ethyl ether, the portions being such that the
temperature of the reaction solution remains below 5.degree. C. The
ice-water bath is removed, and the reaction solution is allowed to
warm up to room temperature and is then stirred at room temperature
for a further 2 hours. The precipitate is filtered off, and the
filtrate is extracted with tert-butyl methyl ether. The organic
phase is washed three times with water, dried over
Na.sub.2SO.sub.4, filtered and concentrated to dryness by
evaporation. The crude product is triturated in hexane and
filtered. The filtrate is concentrated to dryness by evaporation
and dried in a vacuum oven at 40.degree. C. 0.39 g (62% of the
theoretical yield) of a pure compound of the formula 38
164. is obtained in the form of a solid beige substance having a
melting point of 129.4.degree. C.
25 Elemental analysis: found calculated 54.84% C 55.01% C 5.48% H
5.44% H 12.05% N 12.03% N.
165. The .sup.1H NMR spectrum of the compound obtained corresponds
to the formula given above.
EXAMPLE A28
166. The process set out in Example 2 is repeated using
2-ethylmethylimidazole instead of imidazole to yield a compound of
the formula 39
167. Yield: 69% of the theoretical yield.
26 Elemental analysis: found calculated 56.94% C 57.13% C 7.24% H
7.29% H 16.65% N 16.66% N.
EXAMPLE A29
168. 5.32 g (50 mmol) of chloroformic acid vinyl ester are added
dropwise in portions, with stirring, to a solution, maintained at
below 5.degree. C. using an ice-water bath, of 9.61 g (0.1 mol) of
2-ethylimidazole and 11.13 g (0.11 mol) of triethylamine in 150 ml
of acetonitrile, the portions being such that the temperature of
the reaction solution remains below 5.degree. C. The ice-water bath
is removed, and the reaction solution is allowed to warm up to room
temperature and is then stirred at room temperature for a further 3
hours. The precipitate is filtered off, and the filtrate is
extracted with 300 ml of tert-butyl methyl ether and 500 ml of
water. The organic phase is washed three times with water, dried
over Na.sub.2SO.sub.4, filtered and concentrated to dryness by
evaporation. 13.03 g of crude product are obtained, which are
purified by chromatography over silica gel using
Ethylacetate/acetonitrile (9:1) as eluant, the fractions 12-32
being combined and concentrated to dryness. 9.73 g (42% of the
theoretical yield) of a pure compound of the formula 40
169. are obtained in the form of a colourless liquid.
27 Elemental analysis: found calculated 67.79% C 67.81% C 6.27% H
6.13% H 11.87% N 12.17% N.
170. The .sup.1H NMR spectrum of the compound obtained corresponds
to the formula given above.
EXAMPLE A30
171. 0.57 g (5.1 mmol) of chloroformic acid ethyl ester is added
dropwise in portions, with stirring, to a solution, maintained at
below 3.degree. C. using an ice-water bath, of 1.15 g (5.1 mmol) of
4,5-diphenylimidazole and 0.57 g (5.6 mmol) of triethylamine in 60
ml of acetonitrile, the portions being such that the temperature of
the reaction solution remains below 5.degree. C. The ice-water bath
is removed, and the reaction solution is allowed to warm up to room
temperature and is then stirred further overnight. The precipitate
is filtered off, and the filtrate is concentrated to dryness by
evaporation. The residue is taken up in 50 ml of dichloroethane,
washed three times with water, dried over Na.sub.2SO.sub.4,
filtered and concentrated to dryness by evaporation. 0.94 g of a
crude product is obtained, which is triturated in hexane.
Filtration and evaporation of the organic solvent yield 0.56 g (37%
of the theoretical yield) of a pure compound of the formula 41
172. in the form of a white powder having a melting point of
97.0.degree. C.
28 Elemental analysis: found calculated 73.87% C 73.97% C 5.70% H
5.48% H 9.31% N 9.59% N.
173. The .sup.1H NMR spectrum of the compound obtained corresponds
to the formula given above.
EXAMPLE A31
174. The process set out in Example 2 is repeated using
2-isopropylimidazole instead of imidazole to yield a compound of
the formula 42
175. Yield: 21% of the theoretical yield.
29 Elemental analysis: found calculated 66.59% C 66.65% C 5.67% H
5.59% H 12.95% N 12.96% N.
EXAMPLE A32
176. A solution of 200 g (0.92 mol) of di-tert-butyl dicarbonate in
200 ml of tetrahydrofuran is added dropwise, with stirring, to a
solution, maintained at below 20.degree. C. using an ice-water
bath, of 100 g (0.92 mol) of 2-isopropylimidazole and 11.2 g (0.092
mol) of 4-dimethylaminopyridine in 600 ml of tetrahydrofuran. The
reaction mixture is then stirred overnight at room temperature. The
solvent is then evaporated off, and the residue is taken up in 100
ml of hexane and washed five times with 200 ml of water. The
organic phase is dried over Na.sub.2O.sub.4, filtered and
concentrated to dryness by evaporation. 147.2 g (77% of the
theoretical yield) of a pure compound of the formula 43
177. are obtained in the form of a yellow liquid.
30 Elemental analysis: found calculated 62.83% C 63.16% C 8.83% H
8.13% H 13.31% N 13.40% N.
178. The .sup.1H NMR spectrum of the compound obtained corresponds
to the formula given above.
EXAMPLE A33
179. A solution of 34.4 g (0.22 mol) of chloroformic acid phenyl
ester in 460 ml of acetonitrile is added dropwise, with stirring,
to a solution, maintained at below 20.degree. C. using an ice-water
bath, of 24.2 g (0.92 mol) of 2-isopropylimidazole and 26.6 g (0.23
mol) of triethylamine in 460 ml of acetonitrile. The reaction
mixture is then stirred overnight at room temperature. The solvent
is then evaporated off, and the residue is dissolved in 200 ml of
tert-butyl ethyl ether and washed five times with 100 ml of water.
The organic phase is dried over Na.sub.2SO.sub.4, filtered and
concentrated to dryness by evaporation. 42.8 g (84% of the
theoretical yield) of a pure compound of the formula 44
180. are obtained in the form of a slightly yellow solid substance
having a melting point of 68.6.degree. C.
31 Elemental analysis: found calculated 67.77% C 67.24% C 6.53% H
6.90% H 12.11% N 12.07% N.
181. The .sup.1H NMR spectrum of the compound obtained corresponds
to the formula given above.
EXAMPLE A34
182. 2.91 g (0.011 mol) of chloroformic acid 6-nitroveratryl ester
are added in portions, with stirring, to a solution, maintained at
below 2.degree. C. using an ice-water bath, of 1.15 g (0.011 mol)
of 2-isopropylimidazole and 1.17 g (0.012 mol) of triethylamine in
100 ml of acetonitrile, the portions being such that the
temperature of the reaction mixture is kept below 5.degree. C. The
reaction mixture is then allowed to warm up to room temperature and
is stirred overnight at room temperature. After filtration of the
yellow suspension, the solvent is evaporated off from the filtrate.
The resulting residue is taken up in 100 ml of dichloromethane and
washed three times with water. The organic phase is dried over
Na.sub.2SO.sub.4, filtered and concentrated to dryness by
evaporation. 3.08 g (84% of the theoretical yield) of a pure
compound of the formula 45
183. are obtained in the form of a slightly yellow powder having a
melting point of 137.9.degree. C.
32 Elemental analysis: found calculated 54.75% C 55.17% C 5.53% H
5.17% H 11.90% N 12.07% N.
184. The .sup.1H NMR spectrum of the compound obtained corresponds
to the formula given above.
EXAMPLE A35
185. 5.42 g (50 mmol) of chloroformic acid ethyl ester are added
dropwise in portions, to a stirred solution of 7.55 g (25 mmol) of
2-heptadecylimidazole and 2.78 g (27 mmol) of triethylamine in 100
ml of cyclohexanol, the portions being such that the temperature of
the reaction mixture remains below 25.degree. C. The reaction
mixture is stirred overnight and then the yellowish precipitate is
removed by filtration, and the cyclohexanol is evaporated off from
the filtrate. The residue is dissolved in 400 ml of tert-butyl
ethyl ether and washed four times with water. The organic phase is
dried over Na.sub.2SO.sub.4, filtered and concentrated to dryness
by evaporation. 7.94 g (42% of the theoretical yield) of a pure
compound of the formula 46
186. are obtained in the form of a dark-yellow solid substance
having a melting point of 38.6.degree. C.
33 Elemental analysis: found calculated 72.71% C 72.97% C 11.20% H
11.18% H 7.24% N 7.40% N.
187. The .sup.1H NMR spectrum of the compound obtained corresponds
to the formula given above.
188. II. Measurement of the Gelling Time, at Different
Temperatures, of Epoxy Resin Mixtures Comprising an Imidazole
Compound of Formula I or II
189. A mixture is prepared from 1 g of an epoxy resin comprising
diglycidyl ether of bisphenol A and diglycidyl ether of bisphenol
F, and having an epoxy value of 5.65 equivalents/kg, and
5.65.cndot.10.sup.-4 mol of an imidazole compound of formula I or
II according to Examples A1 to A35, and the gelling time of that
mixture is determined at different temperatures by applying the
curable epoxy resin mixture to a hot plate of the given
temperature, and the time taken for the mixture to gel is measured.
The following Table gives the times in hours (h), minutes (') and
seconds (").
34 Imidazole compound Amount of Gelling time of according to
imidazole comp. Example per g epoxy comp. at 100.degree.
130.degree. 150.degree. C. imidazole 38.0 mg 7'10" 1'15" .sup. 35"
A1 71.2 mg 13'43" 3'01" 1'10" A2 79.1 mg 16'30" 3'45" 1'25" A3 94.9
mg 29'20" 6'40" 2'20" A4 94.9 mg 18'37" 6'42 2'05" A5 126.7 mg
23'40" 5'23" 2'28" A6 198.1 mg 21'08" 5'29" 2'33" A7 93.8 mg 21'10"
5'10" 1'57" A8 101.7 mg 19'12" 3'43" 1,15" A9 140.0 mg 37'40" 7'23"
2'37" A10 173.6 mg 48'00" 8'34" 3'00" A11 122.0 mg 1 h 02' 21'53"
5'38" A12 138.0 mg 1 h 02' 15'54" 8'55" A13 136.9 mg 1 h 04' 19'34"
7'02" A14 not measured A15 132.2 mg 1 h 10' 17'04" 8'52" A16 not
measured A17 182.6 mg 56'00" 14'00" 4'52" A18 217.7 mg 1 h 11'
21'56" 8'17" A19 122.0 mg 27'30" 6'44" 3'00" A20 132.2 mg 27'00"
4'26" 1'58" A21 130.1 mg 35'15" 8'55" 3'05" A22 102.8 mg 46'30"
9'40" 5'00" A23 130.0 mg 25'15" 5'30" 2'00" A24 137.9 mg 40'00"
9'50" 3'40" A25 101.8 mg 58'00" 14'20" 4'25" A26 163.4 mg 39'50"
6'30" 2'57" A27 197.4 mg 45'40" 10'30" 4'23" A28 95.0 mg 41'00"
9'46" 3'30" A29 130.0 mg 27'25" 6'20" 2'57" A30 165.1 mg 1 h 10'
23'10" 11'00" A31 103.0 mg 1 h 55' 32'48" 13'23" A32 118.2 mg 4 h
50' 51'32" 12'41" A33 131.2 mg 1 h 32' 17'45" 7'58" A34 196.8 mg 1
h 50' 20'30" 8'22" A35 213.9 mg 41'28" 8'36 4'05".
190. III. Measurement of the Viscosity of Epoxy Resin Mixtures
Comprising an Imidazole Compound of Formula I or II Before and
After Heating at 50.degree. C. for Several Hours
191. A mixture is prepared from an epoxy resin comprising
diglycidyl ether of bisphenol A and diglycidyl ether of bisphenol F
in a ratio of 15:37 parts by weight, and having an epoxy value of
5.65 equivalents/kg, and an imidazole compound of formula I or II
according to Examples A11 to A35, using 5.65.cndot.10.sup.-4 mol of
an imidazole compound of formula I or II per gram of the epoxy
resin. The viscosity of the epoxy resin mixtures is determined at
40.degree. C., using an Epprecht viscometer, before heating and
after heating at 50.degree. C. for 8 and 24 hours.
35 Imidazole compound according to before Example heating 8 h 24 h
imidazole 300 polymerised A11 1180 1220 A12 960 1840 A13 640 1760
A14 1020 880 A15 510 8160 A16 1040 1440 A17 1720 9280 A18 2480 7680
A19 540 1100 A20 ..1100 1440 A21 580 6400 A22 430 9280 A23 760
12800 A24 540 2680 A25 500 3680 A26 1080 4320 A27 1280 2640 A30 300
940 A31 430 320 A32 410 240 900 A33 720 4160 polymerised A34 1600
900 33920 A35 400 560 740.
192. IV. Manufacture of a Moulded Material
193. 100 g of a diglycidyl ether of bisphenol A having an epoxy
value of 5.54 equivalents/kg are mixed, at room temperature, with
14.5 g of the imidazole compound according to Example A20. That
curable epoxy resin mixture has a gelling time of 6'15" at
130.degree. C., a gelling time of 3'40" at 140.degree. C. and a
gelling time of 2'30" at 150.degree. C. After curing for 15 minutes
at 120.degree. C., the moulded materials made from the curable
epoxy resin mixture have a T.sub.g value of 103.4.degree. C.
194. V. Manufacture of a Surface-Coating
195. 300 g of diglycidyl ether of bisphenol A having an epoxy value
of 1.23-1.37 equivalents/kg, 15.0 g of a diglycidyl ether of
bisphenol A having an epoxy value of 1.15-1.35 equivalents/kg,
containing 10% by weight of the flow agent .RTM.Acrylon, 0.6 g of
benzoin, 135.0 g of TiO.sub.2 and 6.3 g of the imidazole compound
according to Example A20 are mixed in an extruder. Sheet iron is
electrostatically coated with the resulting powder which is stoved
for 20 minutes at 120.degree. C. Film thickness: 58 .mu.m. The
surface-coating has the following properties:
36 Impact (reverse side) = 160 cm/kg Cupping index according = 9.7
mm to Erichsen Acetone test*.sup.) = film surface unchanged (best
score) Flow**.sup.) = score 8 Gloss 60.degree. C. (%) = 106.
*.sup.)A cotton swab impregnated with acetone is placed on the
coated surface for 1 minute. It is then tested whether the coating
surface can be scratched with a finger nail. **.sup.)visual
evaluation: score 4 = best result, score 16 = worst result.
* * * * *