COMPOSITIONS CONSISTING OF BRØNSTED ACIDS AND MONOAMINES

Abstract

The present invention provides compositions consisting of a) at least one metal salt, ammonium salt or phosphonium salt of a strong Brønsted acid and b) at least one primary aliphatic monoamine, processes for preparation thereof and use thereof.

Claims

1. A composition consisting of a) at least one metal salt, ammonium salt or phosphonium salt of a strong Brønsted acid and b) at least one primary aliphatic monoamine.

2. The composition according to claim 1, wherein the composition has from 10 to 95% by weight of component a) and 5-90% by weight of component b), based on the weights of components a) and b).

3. The composition according to claim 1, wherein the at least one metal salt a) is a salt of an acid selected from the group consisting of oxalic acid, p-toluenesulfonic acid, trifluoroacetic acid, tetrafluoroboric acid, nitric acid, sulfuric acid, hydrochloric acid, hydrochloric acid, perchloric acid, trifluoromethanesulfonic acid, hydrogen iodide, hexafluorophosphoric acid and hexafluoroantimonic acid.

4. The composition according to claim 1, wherein the Brønsted acid has a pK.sub.A not higher than −9.01.

5. The composition according to claim 1, wherein the at least one primary aliphatic monoamine b) has exclusively aliphatic radicals having from 3 to 30 carbon atoms.

6. The composition according to claim 1, wherein the at least one primary aliphatic monoamine b) has a boiling point, measured at 1013.25 hPa, of from 30 to 300° C.

7. The composition according to claim 1, wherein the at least one primary aliphatic monoamine b) is selected from the group consisting of n-propylamine, isopropylamine, n-butylamine, sec butylamine, tert butylamine, n-pentylamine, n-hexylamine and ethanolamine.

8. The composition according to claim 1, wherein the at least one metal salt a) of the strong Brønsted acid is calcium triflate, and the at least one primary aliphatic monoamine b) is n-butylamine.

9. The composition according to claim 1, wherein the at least one metal salt a) is calcium triflate and at least one primary aliphatic monoamine b) is n-butylamine.

10. The process for preparing the composition according to claim 1, in which a) at least one metal salt, ammonium salt or phosphonium salt of a strong Brønsted acid and b) at least one primary aliphatic monoamine are mixed with one another.

11. A catalyst composition comprising the composition according to claim 1.

12. An epoxy resin catalyst composition comprising the composition according to claim 11.

13. A catalyst composition comprising a) at least one metal salt, ammonium salt or phosphonium salt of a strong Brønsted acid, and b) at least one primary aliphatic monoamine.

14. The catalyst composition according to claim 13, wherein the catalyst composition has from 10 to 95% by weight of component a) and from 5 to 90% by weight of component b), based on the weights of components a) and b).

15. The catalyst composition according to claim 1, wherein the at least one metal salt a) is a salt of an acid selected from the group consisting of oxalic acid, p-toluenesulfonic acid, trifluoroacetic acid, tetrafluoroboric acid, nitric acid, sulfuric acid, hydrochloric acid, hydrochloric acid, perchloric acid, trifluoromethanesulfonic acid, hydrogen iodide, hexafluorophosphoric acid and hexafluoroantimonic acid.

16. The catalyst composition according to claim 1, wherein the Brønsted acid has a pK.sub.A not higher than −9.01.

17. The catalyst composition according to claim 1, wherein the at least one primary aliphatic monoamine b) has exclusively aliphatic radicals having from 3 to 30 carbon atoms.

18. The catalyst composition according to claim 1, wherein the at least one primary aliphatic monoamine b) has a boiling point, measured at 1013.25 hPa, of from 30 to 300° C.

19. The catalyst composition according to claim 1, wherein the at least one primary aliphatic monoamine b) is selected from the group consisting of n-propylamine, isopropylamine, n-butylamine, sec butylamine, tert butylamine, n-pentylamine, n-hexylamine and ethanolamine.

20. The catalyst composition according to claim 1, wherein the at least one metal salt a) of the strong Brønsted acid is calcium triflate, and the at least one primary aliphatic monoamine b) is n-butylamine.

Description

DETAILED DESCRIPTION

[0016] The present invention thus provides compositions consisting of a) at least one metal salt, ammonium salt or phosphonium salt of a strong Brønsted acid and b) at least one primary aliphatic monoamine.

[0017] The compositions preferably have 10-95% by weight of component a) and 5-90% by weight of component b), based on the weights of components a) and b). The compositions further preferably have 30-70% by weight of component a) and 70-30% by weight of component b), based on the weights of components a) and b), even further preferably 40-60% by weight of component a) and 60-40% by weight of component b), based on the weights of components a) and b).

[0018] The compositions according to the invention comprise at least one metal salt, ammonium salt or phosphonium salt of a strong Brønsted acid. Corresponding salts are good catalysts. Such a strong acid in the present context is understood to mean a salt having a pKa (or in the case of polyprotic acids having a pKa of the first protolysis stage) of not more than 2. Preferably, the pKa of the corresponding acid is not more than −2.

[0019] The pKa is defined as the negative decadic logarithm of the equilibrium constant Ka and is considered to be a measure of the strength of an acid. The smaller a pKa, the stronger the acid. The pKa is determined as disclosed in F. G. Bordwell, “Equilibrium Acidities in Dimethylsulfoxide Solution”, Acc. Chem. Res. 1988, 21, 456-463.

[0020] Preferred salts are the corresponding salts of the strong acids collated in the first column in Table 1 below:

TABLE-US-00001 TABLE 1 Literature reference, if not disclosed in Acid pK.sub.A Bordwell Oxalic acid 1.5 Beyer Walter, Lehrbuch der organischen Chemie [Organic Chemistry], 21st edition, Hirzelverlag 1988, p. 324 p-Toluenesulfonic 0.7 Römpp Lexikon Chemie [Römpp's acid Chemical Lexicon], 10th edition, Georg Thieme Verlag, Stuttgart, New York, Verlag 1999, p. 4580-1. Trifluoroacetic 0.2 Beyer Walter, Lehrbuch der organischen acid Chemie [Organic Chemistry], 21st edition, Hirzelverlag 1988, p. 272 Tetrafluoroboric −0.4 e-EROS Encyclopedia of Reagents for acid Organic Synthesis, Pages 1-4, Conference; General Review; Online Computer File, 2001 Nitric acid −1.4 Hollemann Wiberg, Lehrbuch der anorganischen Chemie [Inorganic Chemistry], 91st-100th edition, Walter de Gruyter Verlag, Berlin, New York, 1985, p. 603. Sulfuric acid −3 Römpp Lexikon Chemie, 9th edition, Georg Thieme Verlag, Stuttgart, New York 1991, p. 3459. Hydrochloric acid −8 Hydrobromic acid −9 Perchloric acid −10 Hollemann Wiberg, Lehrbuch der anorganischen Chemie [Inorganic Chemistry], 91st-100th edition, Walter de Gruyter Verlag, Berlin, New York, 1985, p. 428 Trifluoromethan- −14 esulfonic acid Hydrogen iodide −9.5 Journal of Physical Chemistry A, Volume 120, Issue 20, Pages 3663-3669. Hexafluorophos- −10 http://www.periodensystem-online.de/ phoric acid index.php?sel=wertdesc&prop=pKs- Werte&show=list&id=acid Hexafluoroan- −17 http://www.periodensystem-online.de/ timonic acid index.php?sel=wertdesc&prop=pKs- Werte&show=list&id=acid

[0021] Preferably, the salt is the salt of a very strong acid, such a very strong acid in the present context being understood to mean an acid having a pKa (or in the case of polyprotic acids having a pKa of the first protolysis stage) of not higher than −9.01. Preferably, the pKa of the very strong acid is between −9.5 and −25, more preferably between −9.9 and −21.

[0022] Most preferably, component a) is a salt of a Brønsted acid selected from perchloric acid, trifluoromethanesulfonic acid, hydrogen iodide, hexafluorophosphoric acid and hexafluoroantimonic acid.

[0023] Even further preferably, the salt is a triflate, i.e. a salt of trifluoromethanesulfonic acid.

[0024] The strong Brønsted acids are metal, ammonium or phosphonium salts. Metal salts are understood here to mean both salts containing metal ions (i.e. having at least one ion derived from at least one metal, preferably having an ion derived from at least one metal atom, more preferably having exactly one ion derived from at least one metal atom) and metal-containing ions (i.e. also having nonmetallic components). The counterions of the acids mentioned are thus selected from metal ions, metal-containing ions, phosphonium ions and ammonium ions.

[0025] Preferred metal ions are alkaline earth metal cations, especially beryllium, magnesium, calcium, strontium and barium ions, and lithium, aluminium, bismuth, zinc and europium ions.

[0026] Metal-containing ions are ions that contain at least one metal but are not pure metal ions. They are preferably metal compound ions, for example tetraphenylstibonium ions.

[0027] Ammonium ions may be unsubstituted (═NH.sub.4.sup.+), alkylated and/or arylated. Phosphonium ions may be unsubstituted (═PH.sub.4.sup.+), alkylated and/or arylated. A preferred ammonium ion is NH.sub.4.sup.+. A preferred phosphonium ion is PH.sub.4.sup.+. Very particular preference is given to ammonium ions.

[0028] Preferred salts of strong acids are calcium triflate, europium triflate, barium triflate, aluminium triflate, bismuth triflate, lithium triflate, lithium perchlorate, barium perchlorate, lithium hexafluorophosphate and zinc perchlorate. Very particular preference is given to calcium triflate, europium triflate, lithium hexafluorophosphate and lithium perchlorate.

[0029] The best results are achieved with calcium triflate.

[0030] The compositions also include at least one primary aliphatic monoamine. A primary aliphatic monoamine is understood in the present context to mean a primary monoamine (i.e. an amine having only one primary amino group) having exclusively aliphatic, i.e. linear or branched, alkyl radicals, cycloalkyl radicals and/or (cyclo)alkyl radicals. (Cyclo)alkyl radicals are understood here to mean radicals having both cyclic and linear or branched alkyl moieties. Preferred aliphatic radicals each have 3 to 30, more preferably 3 to 10, most preferably 3-6, carbon atoms. The monoamines may be substituted by a hydroxy radical on one of their alkyl, cycloalkyl, and/or (cyclo)alkyl radicals. However, no other substituents are present. Preferably, in addition, all aliphatic radicals of the monoamine are unsubstituted.

[0031] Preference is given to using monoamines having a boiling point (measured at 1013.25 hPa) of 30-300° C., preferably 30-200° C.

[0032] The monoamine is most preferably selected from the group consisting of n-propylamine, isopropylamine, n-butylamine, sec butylamine, tert butylamine, n-pentylamine, n-hexylamine and ethanolamine.

[0033] Even further preferably, the monoamine is n-butylamine.

[0034] The best results are achieved when component a) is calcium triflate and component b) is n-butylamine.

[0035] The present invention further provides a process for preparing the composition according to the invention, in which a) at least one metal salt, ammonium salt or phosphonium salt of a strong Brønsted acid and b) at least one aliphatic monoamine are mixed with one another, optionally in the presence of further components.

[0036] The present invention also further provides for the use of a composition of the invention as catalyst composition. The compositions of the invention are especially suitable as catalyst compositions for the curing of epoxy resins, very preferably for the curing of epoxy resins with amines.

EXAMPLES

Example 1

[0037] To demonstrate the particular reactivity of the catalysts claimed, model experiments are compared with one another. For this purpose, 0.025 mol (3.75 g) of 1,2-epoxy-3-phenoxypropane is added to a mixture of 22.7 g of toluene (solvent) and 2.08 g of tetradecane (internal standard). To this are added 0.025 mol (2.13 g) of piperidine, and 0.06 g of calcium triflate dissolved in the same amount of amine, or alcohol as comparison. Immediately after the mixing, a GC is taken and the content of 1,2-epoxy-3-phenoxypropane is compared with the content of tetradecane. After 4 h at room temperature (RT), by means of GC analysis, the residual content of 1,2-epoxy-3-phenoxypropane (EP) is ascertained (calibrated by the internal tetradecane standard). This gives the following results:

TABLE-US-00002 Comparison of the catalysts Residual % EP Residual % EP after 4 Amine or alcohol in the 0 sample hours at RT 1 No amine or alcohol 97 0 2 Butylamine 78 3 3 Hexylamine 75 4 4 Octylamine 76 4 5 3-Methylpropylamine 83 4 6 2-Ethylhexylamine 78 5 7 2-Ethylpropylamine 85 6 8 n-Pentylamine 77 2 9 Ethanolamine 78 8 Comp. 1 Ethanol 89 32 Comp. 2 Ethylene glycol 89 32 Comp. 3 Propanediol 86 46 Comp. 4 Butanediol 96 31 Comp. 5 Ethylenediamine 90 33

[0038] The claimed monoamines are suitable as solvents for calcium triflate and do not lead to any significant decrease in reactivity (residual EP content after 4 hours not more than 10%). Pure alcohols, dialcohols or diamines lead, by comparison, to a distinct decrease in reactivity.