DE1024078B - Process for the preparation of N, N'-bis [(1-aminocycloalkyl) methyl] alkylenediamines suitable as hardeners for epoxy resins - Google Patents

Description

GERMAN

The invention relates to a process for the preparation of new tetramines, namely N, N'-bis - [(1-aminocycloalkyl) methyl] alkylenediamines.

Amines are used to prevent corrosion, to clean gases and to produce emulsifiers for polishes, pesticides and oils as well as for the production of dyes, detergents, Textile auxiliaries and used for photography purposes. For some time now, they have also been available on a larger scale than Hardener for epoxy resins (Äthoxylinharze) used, however, the epoxy resins obtained in this way had a dark, almost black color, which greatly impaired its scope of application.

The invention is based on the object of creating new, valuable amines that are economical can be manufactured and is excellent as a. Hardeners are suitable for obtaining valuable epoxy resins.

It has now been found that novel tetramines, namely NjN'-Bis- ^ l-aminocycloalkylj-methylJ-alkylenediamines, can be prepared if N, N'-bis - [(1-nitrocycloalkyl) -methylj-alkylenediamines in the presence of a Catalyst and preferably hydrogenated in a solvent at temperatures between the freezing point and the boiling point of the mixture. The hydrogenation is expediently carried out at elevated pressure, for example up to 1000 kg / cm ² , and temperatures above 20 °. The hydrogenation catalysts used are the metals of Group VIII of the Periodic Table, preferably deposited in a finely divided state on a support. Lower alkanols, alcohol-water mixtures, ethers or hydrocarbons are expediently used as solvents. The catalyst and other insoluble substances are mechanically removed from the reaction product, e.g. B. by filtration, removed, the solvent is, preferably under reduced pressure, distilled off and the tetramine, z. B. separated by vacuum distillation.

The hydrogenation can be carried out at ordinary or elevated pressure. ,

Unless otherwise stated, the quantities given are by weight.

example 1

About 15 parts of Raney nickel and 205 parts of N, N'-bis - [(l-nitrocyclohexy ^ -methylj-ethylenediamine were in process of manufacture

of suitable as hardeners for epoxy resins

N, N'-bis [(l-ammocycloalkyl) methyl] -

alkylenediamines

Applicant:

EI du Pont de Nemours and Company,
Wilmington, Del. (V. St. A.)

Representative: Dr.-Ing. G. Knoth, patent attorney,
Hamburg-Wellingsbüttel, Up de Worth 24

Claimed priority:
V. St. v. America 7 October 1955

Robert Arthur Smiley, Woodbury, NJ (V. St. A.),
has been named as the inventor

added to an autoclave to 820 parts of 95% ethanol and stirred at 35 to 75 ° and under a hydrogen gas pressure of 56 to 70 kg / cm ² until no more hydrogen was absorbed. The vessel was then cooled and the reaction mixture filtered, leaving the catalyst. The filtrate was hydrogenated twice more under the same conditions, the filtrates were combined and the ethanol was distilled off by distillation at a pressure of 60 mm Hg. The distillation residue, distilled in vacuo, gave a clear, water-; light-colored, viscous liquid with a _{b.p. 0j6} = 171 °. There were -352 parts of N.N'-Bis-Kl-aminocyclohexyty-methyll-ethylene-, diamine of the formula

- CH ₂

NH ₉

H ₂ N

X —CH ₂ -NH- (CH ₂ ) _ä —NH-CH ₂ --C:

; ch ₂

C H 2 -

obtained, which corresponds to a yield of 64%.

709 879/399

Example 2

37 parts of N.N'-Bis-til-nitrocyclohexylJ-methylj-ethylenediamine and about 5 parts of Raney nickel were added to 198 parts of absolute ethanol in a shake flask made of chemically resistant glass (Pyrex glass), and the mixture was at room temperature and hydrogenated under a hydrogen pressure of 4.2 kg / cm ² in a hydrogenation device according to P arr, which required 3 hours. The hydrogen pressure was then 0.35 kg / cm ² . The mixture was then cooled, the catalyst was filtered off and the alcohol was distilled off. The distillation residue was distilled in vacuo, with 15 parts, corresponding to a yield of 48% _T .N, N'-bis - [(l-aminocyclohexyl) methyl] ethylenediamine as a colorless, viscous oil of n% = 1.5067 and Bp. _{0> 50 to 5} 0.55 = 166 to 168 ° were obtained. The product was identified as N.N'-Bis-Kl-aminocyelohexy ^ -methylj-ethylenediamine by elemental analysis.

20th

C ₁₆ H ₃₄ N ₄ : CH N

Found 67.80% 12.30% 19.54%

67.97% 12.17% 19.69%

Calculated 68.08% 12.05% 19.85%

Example 3

30th

40 parts of N, N'-bis [(l-nitrocyclohexyl) methyl] hexamethylenediamine and about 5 parts of Raney nickel were added to 156 parts of absolute ethanol and the mixture in the reaction vessel at room temperature and a hydrogen pressure of 0.7 to 3 , 5 kg / cm ² shaken until no more hydrogen was absorbed. The reaction mixture was then filtered to remove the catalyst, the ethanol was driven off, the distillation residue was dissolved in 10% hydrochloric acid and the acidic solution was extracted with diethyl ether. The ether extract was discarded and the aqueous solution made alkaline with 10% sodium hydroxide solution. The precipitated tetramine was then taken up in ether, the ether extract was dried over anhydrous magnesium sulfate, filtered and distilled to remove the ether. The residue was then subjected to vacuum distillation, with 16 parts, corresponding to a yield of 46.5%, of N, N '- bis [(I - aminohexyl) methyl] - hexamethylenediamine as a colorless, viscous liquid of η% = 1, 4995 and b.p.n. = 194 ° were obtained.

Harder

m-phenylenediamine

Methylenedianiline

N, N'-bis - [(l-aminocyclohexyl) -methyl] -ethylene-
diamine

Ν, Ν'-bis [(1-aminocyclohexyl) methyl] hexamethylenediamine

lot

of the amine

in g

6.21

11.39

5.17

15.7

colour

of the hardened
Epoxy resin

black, almost opaque

very dark

weakly colored and clear

weakly colored and clear

50

Analysis for C ₂₀ H ₄₂ N ₄ : C

; Found ... 71.08% 12.55% 16.35%

71.01% 12.47 o / _o 16.27 «/ ο

f Calculated 71.00% 12.42% 16.51%

■ The inventively preparable tetramines are in Generally little or completely miscible with water and miscible in all proportions with acetone, diethyl ether, Ethanol, petroleum ether, toluene, carbon tetrachloride, n-propyl nitrate, ethyl benzoate, cyclohexane and the most other common organic solvents. It has been found that those which can be prepared according to the invention Ν, Ν'-bis [(l.-aminocyeloalkyl) -methyl] -alkylenediamines are excellent hardeners for epoxy resins. The following table shows the hardening properties of two of the tetramines produced according to the invention an epoxy resin in comparison with two other amines heretofore used for this purpose.

In these experiments, 50 g of an epoxy resin (ethoxylin resin), such as, for. B. in Chem. Technik, 1952, P. 35, and Mienes, Kunststoff -verarbeitung, 1955, p. 38, is described, used and heated to 120 ° for 24 hours. The amounts of amine used were based on the Number of active hydrogen atoms based on equivalent. ■ It was also found that when using the according to the invention manufactured tetramines as hardeners for epoxy resins in paints the product is essential remained liquid longer than with the known hardeners. For example, paint solidification occurred Use of dimethylaminopropylamine and diethylaminopropylamine after 1 to 2 days, while mixtures with the amines prepared according to the invention remained liquid for 18 days.

The tetramines that can be prepared according to the invention are also excellent chelating agents for heavy metals, like copper, cobalt and nickel and they can because of their great solubility in hydrocarbons and their chelating ability can also be used advantageously as passivating agents for these metals.

As can be seen from the examples, the N, N'-bis - [(1-aminocycloalkyl) -methyl] -alkylenediamines by passing hydrogen through a mixture of the corresponding dinitro compound, a catalyst and a suitable solvent with good yields into the corresponding tetramines will. Lower alkanols, such as methanol, ethanol and isopropanol, are used as solvents; Ether how Dioxane; Hydrocarbons such as benzene, cyclohexane and petroleum ether; as well as mixtures of alkanols with Water in question. The amount of solvent is insignificant. In general, four times the amount of solvent, based on the weight of the dinitro compound, sufficient.

The hydrogenation is carried out in the presence of suitable hydrogenation catalysts, such as Raney nickel, nickel oxides, finely divided metals of group VIII of the periodic Systems such as nickel, iron, cobalt, platinum, palladium or rhodium are carried out in the usual way. the Catalysts can also be deposited on a support, e.g. B. on pumice stone, asbestos, kieselguhr, Clay, silica gel, or charcoal. Also finely divided copper or copper deposited on a carrier is suitable as a catalyst, as well as palladium black, platinum black, colloidal palladium or platinum and Platinum sponge. The amount of catalyst depends on the temperature, the pressure and the reaction time. It Catalyst quantities of one part to one million parts of dinitro compound are sufficient, but are larger Quantities are useful in order to shorten the reaction time. An excess of catalyst does not cause any decrease the yield. The removed from the reaction mixture

separated catalyst can be regenerated and reused by conventional methods.

The Ν, Ν'-bis [(I -nitrocycloalkyl) methyl] alkylenediamines can at temperatures between the freezing point of the reaction mixture up to its boiling point be hydrogenated, but should not be below for reasons of economy and yield 20 ° work. If lower reaction temperatures are used, cooling must be carried out, and longer ones are used Reaction times to be accepted, while losses of reactants occur at higher temperatures can.

The pressures during the hydrogenation can be between atmospheric pressure and 1000 kg / cm ² or even higher; they are based on the equipment available. The reaction rate increases with the pressure and the reaction time decreases accordingly.

The N, N'-bis [(1-aminocycloalkyl) methyl] alkylenediamines are most easily isolated from the reaction mixture by first removing the catalyst and the ao Separates insolubles, e.g. B. filtered off, then drives off the solvent and the residue is distilled in vacuo.

Except for the N, N'-bis - [(l-nitrocyclohexyl) methyl] alkylenediamines mentioned can also other N, N'-bis - [(l-nitrocycloalkyl) methyl] alkylenediamines, such as the Nitrocycloheptyl or nitrocyclopentyl derivatives, for example propylene or pentamethylene diamine residues be converted into the corresponding amino compounds by the process according to the invention. The process can also be carried out continuously, for example by adding an N, N'-bis - [(1-nitrocycloalkyl) -methylj-alkylenediamine and the catalyst are continuously introduced into a reaction zone in which continuously Hydrogen enters and from which the hydrogenation product is continuously withdrawn. Here can one also the preparation of the N, N'-bis - [(l-nitrocycloalkyl) methyl] alkylenediamines with the hydrogenation to the Ν, Ν'-bis - [(I -aminocycloalkyl) -methyl] -alkylenediamines combine, the hydrogen and the catalyst then being converted directly into the N, N'-bis - [(1-nitrocycloalkyl) methyl] alkylenediamine containing reaction mixture are initiated.

Claims (4)

Patent claims: 1. A process for the preparation of N, N'-bis - [(l-aminocycloalkyl) -methyl] -alkylenediamines which are suitable as hardeners for epoxy resins, characterized in that N, N'-bis - [(l-nitrocycloalkyl) -methyl ] -alkylenediamines hydrogenated in a known manner in the presence of a catalyst and preferably in a solvent at temperatures between the freezing point and the boiling point of the mixture at normal or elevated pressure up to 1000 kg / cm ² and the reaction product after removal of the catalyst and other insoluble substances , by mechanical means, e.g. B. by filtration, and then distilling off the solvent, preferably under reduced pressure, from the distillation residue, e.g. B. separated by vacuum distillation. 2. The method according to claim 1, characterized in that the hydrogenation at temperatures above of 20 ° is made. 3. The method according to claim 1 or 2, characterized in that metals are used as hydrogenation catalysts the VIII. Group of the Periodic Table, preferably in a finely divided state or on a Depressed carrier, used. 4. The method according to claim 1 to 3, characterized in that lower alkanols as solvents, Alcohol-water mixtures, ethers or hydrocarbons can be used. 1 © 709 879/339 2.58