DE2334226A1 - PROCESS FOR THE PRODUCTION OF EPSILON-AMINOCAPRONIC ACID AMIDE - Google Patents

Description

Our sign; O.Z. 29 985 Gr / Wil 67OO Ludwigshafen, July 4, 1973

Process for the preparation of ε-aminocaproic acid amide

The invention relates to a process for the preparation of ε-aminocaproic acid amide from tf-nitrocyclohexanone.

It is known that £ -aminocaproic acid amide is produced by the reaction of To produce έΓ-aminocaproic acid ethyl ester with aqueous ammonia (J. Am. Chem. Soc. 68: 1684 (1946)). Furthermore, it is possible to produce aminocaproamide from ^ -nitrocyclohexanone by Nitrocyclohexanone in solvents such as water or alcohols with the addition of ammonia in the presence of a reduction catalyst is reduced with hydrogen (DOS 1 932 218 or JA 70-15 486). By hydrogenation of ^ -Nltrocaproamideamid aminocaproamide can be obtained.

A disadvantage of producing aminocaproamide from aminocaproic acid ee star is that the starting materials are difficult to access. In the manufacture of aminocaproamide from Nitrocyclohexanone in larger amounts of water or alcohol, on the other hand, is technically complex to work up after the reduction.

It has now been found that ^ -aminocaproamide is obtained in one step in high yields and in good purity if o (- nitro cyclohexanone, <r -nitrocyclohexenol and / or mixtures of af-nitrocyclohexanone and tf-nitrocyclohexenol with hydrogen in liquid ammonia at temperatures of 50 to 15O ⁰ C in the presence of an active hydrogenation catalyst brings into contact.

The process according to the invention provides ε-aminocaproamide in a technically simple way. No by-product formation can be observed. The catalysts used also show sufficient activity in liquid ammonia. This result is surprising since it is described in DT-OS 1,932,218 becomes that the catalytic activity of a hydrogenation catalyst decreases in the pH range above 12 and thereby also the rate of reaction of the hydrogenation.

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For the process of the invention, the liquid ammonia serves as a reactant and solvent. The amount applied will be due to the stoichiometry of the implementation, as the following reactions take place:

0 D

I ^ + NH ^ ^ TO ₂ N- (CH ₂ ) ₅ - <

3oJ 2) / "O ₂ N- (CHg) ₅ -CONH ₂ J ⁷ - SZ- *. H ₃ N- (CH ₂ ) 5-CONH ₂

It is an advantage of the process according to the invention that nitrocyclohexanone is used as the starting material without a reduction in yield on aminocaproamide by the isomeric a-nitrocyclohexenol or replace with mixtures of nitrocyclohexanone and nitrocyclohexenol can.

A particular advantage of the invention is the extremely easy separation of the aminocaproamide formed from the catalyst. It has also been found that aminocaproamide is completely soluble in liquid ammonia. Therefore, the catalyst can after the reaction has ended - for example by filtration completely of the ε-aminocaproic acid amide dissolved in the liquid ammonia be separated. After the ammonia has evaporated, the ε-aminocaproic acid amide is obtained in such purity that it can be processed further without additional cleaning.

The amount of ammonia used should expediently be at least one mole per mole of nitrocyclohexanone. Since, however, the ammonia continues to play the role of the solvent, it should be so high that that of ft-nitrocyclohexanone at the reaction temperature resulting C-nitrocaproic acid amide dissolved in the liquid

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Ammonia is present. In this way the hydrogenation becomes £ - Aminocaproamide significantly accelerated. The necessary amount of ammonia is given by the solution equilibrium £ -nitrocaproamide to liquid ammonia (Fig. l). So the amount of ammonia chosen is usually in the range of 10 to 50 moles per mole of Ä-nitrocyclohexanone, but are higher Ammonia concentrations are not disadvantageous for the process according to the invention.

Generally the reaction is carried out at a temperature between 50 and 150 ⁰ C, preferably at 70 to 150 ⁰ C, particularly at temperatures between 90 and 120 ⁰ C and a pressure of 20 to 200 bar, preferably from 50 to I50 bar, in particular at a pressure between 80 and 120 bar. You can work either continuously or batchwise.

All known catalysts which are used in catalytic hydrogenation can be used as active hydrogenation catalysts are effective under the reaction conditions according to the invention. Useful catalysts include: Cobalt, nickel, Palladium, platinum and compounds of these metals have been shown to form these metals under the reaction conditions. For example one can use nickel-containing catalysts, such as reduced nickel, Raney nickel, palladium-containing catalysts, such as Palladium-carbon, palladium-barium sulfate, platinum-containing catalysts, such as platinum-carbon, platinum oxide and cobalt-containing catalysts such as Raney cobalt, reduced cobalt, if appropriate Use straps.

The amount of catalyst is not critical. The preferred range is 0.1 to 40% by weight , based on the starting material used.

The reaction can be carried out as follows: In a reaction vessel become tf-nitrocyclohexanone, hydrogenation catalyst and ammonia filled. Then, hydrogen is introduced under pressure and the reaction system is brought to the reaction temperature with stirring. The implementation is initiated. the The reaction is then continued until the hydrogen uptake

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has practically ended. After the reaction, the reaction mixture is allowed to cool, the reaction vessel is let down and the reaction residue is removed in an inert solvent and separates off the hydrogenation catalyst. However, you can also use the hydrogenation catalyst separate under pressure and then transfer the reaction mixture to a zone of low pressure releasing Lead to ammonia. The remaining reaction residue can be extracted or recrystallized to give pure £ f-aminocaproic acid amide to obtain. Normally, however, the purity of the E-aminocaproic acid amide obtained as the reaction residue is sufficient.

The 6- aminocaproamide produced by the process of the invention is a valuable intermediate for the production of caprolactam.

example 1

7 * 15 g (0.05 mol) c (-Nitrocyclohexanon together with 2.0 g of a nickel catalyst of 49% reduced nickel on kieselguhr, and 50 ml of liquid ammonia in a 250 ml steel autoclave added. At 20 ⁰ C is hydrogen to a total pressure of 50 bar and the autoclave is ^{heated with stirring to 50 °} C. After 2 hours at the reaction temperature, the autoclave is cooled and depressurized Obtained in the form of white crystals with a melting point of 50 to 51 ° C. The infrared absorption spectrum of the substance agrees completely with that of i- aminocaproic acid amide. The yield is 94.5%. The obtained e-aminocaproic acid amide is pure according to thin-layer chromatography.

Examples 2 to 9

In the same procedure as described in Example 1, a-nitrocyclohexanone and / or ct-nitrocyclohexenol are converted to aminocaproone

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ORIGINAL INSPECTED

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amide in liquid ammonia under varied conditions, which are given in Table 1 below. The one with it The results obtained are also shown in Table 1.

Example 10

The procedure described in Example 1 is repeated. After the reaction has ended, the reduction catalyst is filtered off under pressure, the ammoniacal solution of ε-aminocaproamide is depressurized and the ε-aminocaproamide is obtained as a residue. Yield is $ 92.5>, The Γ-aminocaproic acid amide is pure according to thin-layer chromatography.

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Table 1

Example NCH No. (g)

r +)

NK, liquid catalyst (äl)

Initial pressure R. temp. R.-time yield (° C) (h) (*)

+) NCH = A-nitrocyclohexanone or «-nitrocyclohexenol and / or mixtures of
^ -Nitrocyclohexanone and <* - nitrocyclohexenol

2
3
4th 7.2
7.2
7.15 50
40
50 2 g Pd / BaSO ^ (10 ^)
2 g Pd / BaS0 ₄ ( $ 10)
2 g Pd / C (10 %) 50
100
100 50
100
100 2
1.5
2 81
97
88 CD 5 7.15 35 2 g Pt / C (10 Ji) 50 50 2.5 82 9883 / β
7th 7.15
7.2 40
50 2 g Ni / kieselguhr (37 %)
2 g Ni / kieselguhr (37 %) 100
50 120
50 2
3 90
82 * co 8th 7.2 50 2.9 grams of Raney nickel 100 100 2.5 90 co
to 9 7.2 60 3, og Raney cobalt 120 120 2.5 84

Claims (5)

Claims 1.) Process for the preparation of fc-aminocaproamide from nitrocyclohexyl compounds by hydrogenation in solvents, characterized in that tf-nitrocyclohexanone, tf-nitrocyclohexenol and / or mixtures of tf-nitrocyclohexanone and tf-nitrocyelohexenol with hydrogen in liquid ammonia as the solvent at temperatures 50 to 150 ⁰ C in the presence of an active hydrogenation catalyst are brought into contact. 2. The method according to claim 1, characterized in that a sufficient amount of liquid ammonia to completely dissolve the resulting έ'-nitrocapronamide is used as the solvent. 3. The method according to claim 1 and 2, characterized in that the active hydrogenation catalyst contains at least one metal from group VIII of the periodic table or a compound which forms these metals in the reaction system. 4. The method according to claim 3, characterized in that the active metallic component used is nickel, cobalt, platinum or palladium or compounds of these metals. 5. The method according to claim 1 to 4, characterized in that the active hydrogenation catalyst is separated off after the reaction under the pressure prevailing in the reaction system. Sign. BASF Aktiengesellschaft 409883/133 3 Blank page