CA1248552A

CA1248552A - 1-alkyl-2-aminomethyl-aminocyclohexane and/or 1-alkyl- 4-aminomethyl-aminocyclohexane

Info

Publication number: CA1248552A
Application number: CA000529628A
Authority: CA
Inventors: Erwin Hahn; Peter Neumann
Original assignee: BASF SE
Current assignee: BASF SE
Priority date: 1983-05-17
Filing date: 1987-02-12
Publication date: 1989-01-10

Abstract

ABSTRACT OF THE DISCLOSURE:

This invention describes novel diamines of formu-lae:

Description

124~3S5;2 DIVISIONAL APPLICATION OF
CANADIAN PATENT APPLICATION 454,484 This invention relates to aliphatic diamines.
Specifically it relates to alkyl-substituted amino-aminome-thylcyclohexanes, useful for the preparation of their corre-sponding diisocyanates.
Both aromatic and aliphatic isocyanates are known to the art. Aromatic diisocyanates such as 2,4- and 2,6-1~ toluene diisocyanate, 1,5-naphthylene diisocyanate, 4,4'-diphenylmethane diisocyanate, and mixtures of 4,4'-, 2,4'-, and 2,2'-diphenylmethane diisocyanates and polyphenyl-polymethylene polyisocyanates, aliphatic diisocyanates such as 3-isocyanatomethyl-3,5,5-trimethylcyClohexyl isocyanate are known commercial products which are preferably used to prepare polyurethane plastics. The polyisocyanates are generally prepared from their correspondihg amino compounds through phosgenation and subsequent thermal cleavage of the intermediately formed carbamic chlorides. Numerous organic mono- and polyisocyanates are described, for example, in the Annalen der Chemie 562 (1949), p. 75 ff.
The objective of the invention disclosed in the parent application was to develop cycloaliphatic diisocy-anates with the isocyanate groups having different react-ivity.

Summary of the Invention The objective of the invention disclosed andclaimed in parent application no. 454,484 is achieved with diisocyanates of formulae:

R R
~ CH2NCO ~ NCO

*

~'Z4855'~

or mixtures thereof, in which R ls an alkyl group having from 1 to 12 carbon atoms.
Preferred are diisocyanates of formulae:

R R

2 ~ NCO
(III) ~ (IV) or mixtures thereof, in which the isocyanatomethyl group is bonded in the 2- or 4-position and the isocyanate yroup is in the 4- or 2-position, lS The invention claimed in this divisional applica-tion provides diamines of formulae:

~ CH2NH2 ~ (VI) or mixtures thereof, in which R is an alkyl group having from 1 to 12 carbon atoms, useful for the preparation of the~
diisocyanates of the parent invention. Diamines of for-mulae:

~ -CH2NH2 ~ H2 (VII) ~ (VIII) . -- 2 855'~

or mixtures thereof, are preferred in which the aminomethyl group is bonded at the 2- or 4-position and the amino group at the 4- or 2-position.

Descri tion of the Preferred Embodiments p In formulae (I) through (VIII), R is an alkyl radical having from 1 to 12 carbon atoms, preferably from 1 to 4 carbon atoms, which may be branched, however, is preferably linear. Typical examples of such alkyl radicals are n-pentyl, n-hexyl, n-heptyl, n-octyl, 2-ethyl-n-hexyl, n-nonyl, n-decyl, n-undecyl, n-dodecyl radicals, preferably the ethyl, n- and isopropyl, and n- and sec.-butyl radicals, and more preferably the methyl radical.
The following are typical examples of the diisocy-anates of the parent invention:
1-methyl-2-isocyanatomethyl-3-isocyanato-, 1-me-thyl-2-isocyanatomethyl-5-isocyanato-, 1-methyl-2-isocyan-atomethyl-6-isocyanato-, 1-methyl-4-isocyanatomethyl-3-iso-cyanato-cyclohexane; 1-ethyl-2-isocyanatomethyl-3-isocya-nato-, 1-ethyl-2-isocyanatomethyl-5-isocyanato-, 1-ethyl-2-isocyanatomethyl-6-isocyanato-, 1-ethyl-4-isocyanatomethy-3-isocyanato-cyclohexane; 1-n-propyl-2-isocyanatomethyl-3-isocyanato-, 1-n-propyl-2-isocyanatomethyl-5-isocyanato-, 1-n-propyl-2-isocyanatomethyl-6-isocyanato-, 1-n- propyl-4-isocyanatomethyl-3-isocyanato-cyclohexane; 1-isopropyl-2-isocyanatomethyl-3-isocyanato-, 1-isopropyl-2-isocyanato-methyl-4-isocyanato-, 1-isopropyl-2-isocyanatomethyl-5-iso-cyanato-, l-isopropyl-2-isocyanatomethyl-6-isocyanato-, 1-isopropyl-4-isocyanatomethyl-2-isocyanato-, 1-isopropyl-4-isocyanatomethyl-3-isocyanato-cyclohexane; 1-n-butyl-2-iso-cyanatomethyl-3-isocyanato-, 1-n-butyl-2-isocyanatomethyl-4-isocyanato-, 1-n-butyl-2-isocyanatomethyl-5-isocyanato-, 1-n-butyl-2-isocyanatomethyl-6-isocyanato-, 1-n-butyl-4-iso-cyanatomethyl-2-isocyanato-, 1-n-butyl-4-isocyanatomethyl-3-lZ4855Z

isocyanato-cyclohexane; 1-n-pentyl-2-isocyanatomethyl-4-isocyanato-, l-n-pentyl-2-isocyanatomethyl-6-isocyanato-, 1-n- pentyl-4-isocyanatomethyl-2-isocyanato-cyclohexane; 1-n-hexyl-2-isocyanatomethyl-4-isocyanato-, 1-n-hexyl-2-isocya-natomethyl-6-isocyanato-, 1-n-hexyl-4-isocyanatomethyl-2-isocyanato-cyclohexane; 1-n-heptyl-2-isocyanatomethyl-4-iso-cyanato-, 1-n-heptyl-2-isocyanatomethyl-6-isocyanato-, 1-n-heptyl-4-isocyanatomethyl-2-isocyanato-cyclohexane; 1-n-octyl-2-isocyanatomethyl-4-isocyanato-, 1-n-octyl-2-isocyan-] atomethyl-6-isocyanato-, 1-n-octyl-4-isocyanatomethyl-2-iso-cyanato-cyclohexane; 1-n-nonyl-2-isocyanatomethyl-4-isocyan-ato-, 1-n-nonyl-2-isocyanatomethyl-6-isocyanato-, 1-n-nonyl-4-isocyanatomethyl-2-lsocyanato-cyclohexane; l-n-decyl-2-isocyanatomethyl-4-isocyanato-, 1-n-decyl-2-isocyanatomethyl -6-isocyanato-, 1-n-decyl-4-isocyanatomethyl-2-isocyanato-cyclohexane; 1-n-undecyl-2-isocyanatomethyl-4-isocyanato-, 1-n-undecyl-2-isocyanatornethyl-6-isocyanato-, 1-n-undecyl-4-isocyanatomethyl-2-isocyanato-cyclohexane; 1-n-dodecyl-2-isocyanatomethyl-4-isocyanato-, 1-n-dodecyl-2-isocyanato-methyl-6-isocyanato- and 1-n-dodecyl-4-isocyanatomethyl-2-isocyanato-cyclohexane.
Preferred are: 1-ethyl-2-isocyanatomethyl-4-iso-cyanato-, 1-ethyl-4-isocyanatomethyl-2-isocyanato-cyclohex-ane; 1-n-propyl-2-isocyanatomethyl-4-isocyanato- and 1-n-propyl-4-isocyanatomethyl-2-isocyanato-cyclohexane and more preferably 1-methyl-2-isocyanatomethyl-4-isocyanato-, 1-me-thyl-2-isocyanatomethyl-6-isocyanato-cyclohexane as well as their isomer mixtures and 1-methyl-4-isocyanatomethyl-2-iso-cyanato-cyclohexane.
The new diamines corresponding to the diisocyana-tes cited above are used as the starting components for the preparation of the diisocyanates of the parent invention.
Here the following compounds have proved to be particularly successful and are, therefore, preferably used:

i24SS5'~

1-ethyl-2-aminomethyl-4-amino-, 1-ethyl-4-aminomethyl-2-amino-cyclohexane; 1-n-propyl-2-aminomethyl-2-amino-cyclo-hexane; l-n-propyl-2-aminomethyl-4-amino- and 1-n-propyl-4-aminomethyl-2-amino-cyclohexane; and more preferably 1-me-thyl-2-aminomethyl-4-amino-,1-methyl-2-aminomethyl-6-amino-cyclohexane as well as their isomer mixtures and 1-methyl-4-aminomethyl-2-amino cyclohexane.
The diisocyanates and diamines for these compounds can be present in the form of isomer mixtures, mixtures of the same isomers but with different alkyl radicals, or as mixtures of both types of mixtures.
The preparation of the novel diamines and diisocy-anates can follow the following sequence, for example:

R R
CN ~ CN ~ CH2NH2 N02 ~H2 ~X) (X) \ ~XI

R R

~ CH2NCO ~ 2NH2 (I) (V) The 1-alkyl-2-cyanonitrobenzenes (X) or the 1-alkyl-4-cyanonitrobenzenes can also be prepared in essen-tially known procedures through the nitration of the corre-sponding l-alkyl-2-cyanobenzenes (IX) or 1-alkyl-4-cyanoben-zenes, for example, in the manner described in the Berichte 124~3S5Z

d _ Deutschen Chemischen Gesellschaft (1898), p. 2880 ff. or in the Journal of American Chemical Society 99 (1977), p.
6721 or suitable variants of these methods.
Another method for the preparation of the alkyl-cyanonitrobenzenes cited as an example lies in the knownprocess for exchanging the amino group in the alkyl-amino nitrobenzenes for a nitrile group, corresponding to Journal of Organic Chemistry 44, (1979), p. 4003.
The 1-alkyl-cyanonitrobenzenes obtained in the nitration or their isomer mixtures can be reduced directly, i.e., without further purification, to 1-alkyl-aminomethyl-aminobenzenes or their isomer mixtures. Similar, for exam-ple, to the process described for 2-cyanonitrotoluene in Farmaco (Pavia), Ediz. Sci. 25 (1970), p. 163 (C. A. 72, 121 101 d, 1970). The reduction of the nitro and the cyano group can be completed here in one or two sequential reaction steps. It is not always necessary to add ammonia.
The aromatic ring reduction of the 1-alkyl-2-ami-nomethyl-aminobenzenes (XI) or the 1-alkyl-4-aminomethyl-aminobenzene follows known processes, for example, those cited in Houben-Weyl, Methoden der organischen Chemie, 4th Ed., Vol. XI/1, (Stuttgart: George Thieme Verlag, 1957), p.
678 ff. C. Ferry, Reaktionen der organischen Synthese, (George Thieme Verlag: Stuttgart, 1978), pp. 83, 90 ff.;
A. E. Barkdoll et al, J. Amer. Chem. Soc. 75 (1953), p.
1156, Chemistr _ Letters, (1982), pp. 603-606, U.S. Patent 2,494,563 or German laid-open Application 21 32 547.
In order to prepare the 1-alkyl-2-aminomethyl-aminocyclohexane (V) or the 1-alkyl-4-aminomethyl-amino-cyclohexane, one can also start directly with 1-alkyl-2-cyanonitrobenzenes (X).
The resulting 1-alkyl aminomethyl-aminocyclohex-anes can be phosgenated in solvents either directly or as salts, preferably hydrogen chlorides. Suitable solvents are, for example: toluene, xylene, chlorobenzene, or di-chlorobenzene. A solution of the 1-alkyl-aminomethyl-amino-cyclohexanes or a suspension of the corresponding salts is reacted accordingly at temperatures of approximately 0 C to 100 C, preferably from 10 C to 50 C, with 1 to 6 moles phosgene per NH2 HCl, preferably from 1 to 2.5 moles pho-gene, and the intermediately formed carbamic chloride can be cleaved at temperatures from 80 C to 180 C, preferably form 120 to 160 C in the 1-alkyl-isocyanatomethyl-isocyanatocyclohexane. The gaseous or liquid phosgene is charged directly into the reaction mixture at such a rate that the emerging gases primarily are composed of hydrogen chloride.
After completion of phosgenation and cleavage, the solvent is distilled off at reduced pressure, for example, from 100 to 10 mbar. However, it may also be advantageous to strip the hydrogen chloride or any excess phosgene which may be present from the diisocyanate solution with the aid of nitrogen or another inert gas before the solvent is distilled off.
The resulting crude l-alkyl-2- or 4-isocyanato-methyl-isocyanatocyclohexanes or isomer mixtures can be se-parated and purified by distillation at reduced pressure.
The diisocyanates of the invention can also be prepared through the thermal cleavage of the corresponding diurethanes in the gaseous or liquid phase, if necessary in the presence of catalysts, whereby the diurethanes are ob-tained in an efficacious manner according to the process described in European Patent published application 18 583 (U. S. Patent 4,278,805) through the reaction of carbamate with the l-alkyl-aminocyclohexanes in the presence of alco-hols and, if necessary, urea.
The 1-alkyl-2- or 4-aminomethyl-aminocyclohexanes and l-alkyl-2- or 4-isocyanatomethyl-isocyanatocylohexanes ~Z4855Z

are valuable intermediates and feedstocks for crop protec-tion agents and plastics.
The diamines are preferably converted into diiso-cyanates. Such diisocyanates are particularly well suited for the preparation of polyurethane foams, adhesives, paints, coatings, and sealants.
The following examples are intended to further explain the invention without necessarily limiting its scope.
EXAMPLE 1:
a) Preparation of an isomer mixture of 1-methyl-2-cyano-4-nitrobenzene and 1-methyl-2-cyano-6-nitrobenzene Twelve hundred parts by weight concentrated sul-furic acid were cooled to -5 C in a reaction flask equipped with an addition funnel, a stirrer, and a thermometer.
While stirring well, 200 weight parts 2-cyanotoluene follow-ed by 151 weight parts concentrated nitric acid between -5 C and ~5 C were added dropwise within one hour. In order to complete the nitration, stirring continued for an additional 1.5 hours at 0 C, whereupon the reaction mixture was poured onto 2000 weight parts ice. The precipitate was filtered off, the filtered solid was thoroughly washed with water and dried on clay.
Two hundred and eighty-two weight parts of a crude isomer mixture of 1-methyl-2-cyano-4- and 6-nitrobenzene were obtained at a weight ratio of approximately 87:13 and having a melting point of from 91 C to 92 C.
b) Preparation of an isomer mixture of 1-methyl-2-aminomethyl-4- and 6-aminobenzene One hundred weight parts of the isomer mixture of 1-methyl-2-cyano-4- and 6-nitrobenzene obtained in accordan-ce with a) were dissolved in 800 weight parts ethanol and hydrogenated at 50 bar and 80 C after adding 25 weight ~Z4855Z

parts Raney nickel. The catalyst was filtered off after cooling to room temperature, the filtra~e was concentrated at reduced pressure, and the residue was distilled. One then obtained 76 weight parts of a mixture of 1-methyl-2-aminomethyl-4- and 6-aminobenzene in the form of an oil which solidified qulckly. This mixture distilled at 135 C
to 180 C (0.3 mbar).

C8H12N2 (Molecular weight 136, mass spectrometry) c) Preparation of an isomer mixture of l-methyl-2-aminomethyl-4- and 6-aminocyclohexane Fifty weight parts of the 1-methyl-2-aminomethyl-4- and 6-aminobenzene obtained in accordance with b) were hydrogenated in 400 volume parts dioxane in the presence of 1.5 weight parts ruthenium oxide hydrate (prepared in ac-cordance with German Patent 2132547) at 150 C and 250 bar.
After cooling to room temperature, the catalyst was filter-ed off, the filtrate was concentrated at a reduced pressure and the residue was distilled.
Thirty-two weight parts of a mixture of 1-methyl-2-aminomethyl-4 and 6-aminocyclohexane were obtained. This mixture distilled at 83 C to 85 C (0.4 mbar).

Analysis: C8H18N2 (Molecular weight: 142, mass spectrome-try) C H N

Calculated, % by wt. 67.55 12.75 19.69 Found, % by weight 67.30 12.70 19.60 d) Preparation of an isomer mixture of 1-methyl-2 -isocyanatomethyl-4- and 6-isocyanatocyclohexane A solution of 14.2 weight parts of the isomer ., _ g 12~8552 mixture of l-methyl-2-aminomethyl-4- and 6-aminocyclohexane obtained in accordance with c) in 100 weight parts o-dichlo-robenzene were added dropwise while stirring to a mixture of 260 weight parts o-dichlorobenzene and 80 weight parts phos-S gene cooled to 0 C. After completion of the addition, themixture was heated slowly to 130 C and phosgene was direct-ed through the reaction mixture at this temperature for 1.5 hours. Then the reaction mixture was cooled to room tempe-rature and excess phosgene was removed by sparging nitrogen into the mixture. Then the solvent was first distilled off at 10 to 20 mbar and thereupon the residue was distilled under hlgh vacuum. Ten and one-half weight parts of a mixture of 1-methyl-2-isocyanatomethyl-4- and 6-isocyanato-cyclohexane having a distillation range of 110 C to 112 C
(ca. 0.1 mbar) were obtained.

Analysis: C1oH14N2O2 (Molecular weight: 194, mass spectro-metry) C H N O

Calculated, % by wt. 61.837.26 14.42 16.47 Found, % by wt.62.20 7.5014.40 16.00 EXAMPLE 2:
a) Preparation of 1-methyl-4-cyano-2-nitrobenzene Two hundred and forty weight parts of concentrated sulfuric acid were cooled to -5 C in a reaction flask equipped with an addition funnel, stirrer, and thermometer.
While stirring well, 40 weight parts 4-cyanotoluene was added in portions and then 25 volume parts concentrated nitric acid between -5 C and +5 C was added dropwise. In order to complete the nitration, the mixture was stirred for an additional two hours at 0 C and the reaction mixture was i24~35~2 then poured onto 400 weight parts ice. The precipitate was filtered off, the filtered material was thoroughly washed with water and air-dried.
The product (50.9 weight parts) was 1-methyl-4-cyano-2-nitrobenzene having a melting point of from 105 C
to 10~ C.
b) Preparation of 1-methyl-4-aminomethyl-2-amino-benæene Sixty weight parts of the 1-methyl-4-cyano-2-] nitrobenæene obtained in accordance with a) were dissolvedin 800 weight parts ethanol and, after adding 20 weight parts Raney nickel, hydrogenated at 10 bar and 60 C until no further hyrogen was consumed. After adding 8 volume parts 3 percent ammonia solution, the hydrogenation was again undertaken at 10 bar and 60 C. After cooling to room temperature, the catalyst was filtered off and the filtrate was concentrated at reduced pressure. The residue was dis-tilled under a high vacuum. Thirty-two and one-tenth weight parts 1-methyl-4-aminomethyl-2-aminobenzene were obtained, having a distillation range of from 130 C to 135 C (0.3 mbar).

C H N

Calculated, ~ by wt. 70.55 8.88 20.57 Found, ~ by wt. 70.80 9.00 19.90 c) Preparation of 1-methyl-4-aminomethyl-2-amino-cyclohexane Twenty weight parts of the l-methyl-4-aminomethyl-2-aminobenzene obtained in accordance with b) were hydrogen-ated in lS0 volume parts dioxane in the presence of O.S
weight parts ruthenium oxide hydrate (prepared in accordance with German Patent 2132547) at 150 C and 250 bar. ~.fter 1248~5Z

cooling to room temperature, the catalyst was filtered off, the filtrate was concentrated at reduced pressure, and the residue was distilled. Fourteen and four-tenths weight parts 1-methyl-4-aminomethyl-2-aminocyclohexane were ob-tained having a boiling point of from 60 C to 63 C (0.04 mbar).

Analysis: C8H18N2 (Molecular weight: 142, mass spectrome-try) C H N

Calculated, ~ by wt. 67.55 12.75 19.69 Found, ~ by weiyht 67.40 12.60 19.90 d) Preparation of 1-methyl-4-isocyanatomethyl-2-isocyanatocyclohexane A solution of 9.1 weight parts of the 1-methyl-4-aminomethyl-2-aminocyclohexane obtained in accordance with c) in 75 weight parts o-dichlorobenzene were added dropwise while mixing to a mixture of 150 weight parts o-dichloroben-zene and 55 weight parts phosgene cooled to 0 C. After completion of this addition, the mixture was slowly heated to 130 C and phosgene was directed into the reaction mixture at this temperature for 15 hours.
Then the reaction mixture was cooled to room tem-perature, and the excess phosgene was separated by using nitrogen. Thereupon, the solvent was distilled off at from 10 to 20 mbar and the residue was distilled under high vacuum. Two and four tenths weight parts l-methyl-4-iso-cyanatomethyl-2-isocyanatocyclohexane having a boiling point of 98 C to 102 C ~0.4 mbar) were obtained.

Analysis: CloH14N2O2 (Molecular weight: 194, mass spectro-metry)

Claims

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A diamine selected from the group consisting of (V) (VI) and a mixture thereof, in which R is an alkyl group having from 1 to 12 carbon atoms.

2. A diamine of claim 1 selected from the spe-cific isomers of the following formulae:
(VII) (VIII) or a mixture thereof, in which R is an alkyl group having from 1 to 12 carbon atoms.

3. The diamine of claim 2 in which R is a methyl, ethyl, n-propyl, isopropyl or n-butyl group.

4. 1-methyl-2-aminomethyl-4-aminocyclohexane.

5. 1-methyl-2-aminomethyl-6-aminocyclohexane.

6. 1-methyl-4-aminomethyl-2-aminocyclohexane.