WO2012018310A1

WO2012018310A1 - Process for the production of highly pure dicyclohexylamine from by-products resulting from the producton of cyclohexylamine

Info

Publication number: WO2012018310A1
Application number: PCT/SK2011/050010
Authority: WO
Inventors: Jan Uhlar; Ivan Macak; Michal Stefanko; Milan Kralik; Jaroslav Horak; Stefan Chovanec; Pavel Biro; Branislav Brezny
Original assignee: Duslo, A.S.
Priority date: 2010-08-02
Filing date: 2011-08-02
Publication date: 2012-02-09
Also published as: SK500352010A3; SK288006B6; EP2601170A1

Abstract

Title: Process for the production of highly pure dicyclohexylamine from by- products resulting from the production of cyclohexylamine Process for the production of highly pure dicyclohexylamine during the production of cyclohexylaminefrom aniline in a liquid phase on ruthenium catalyst on thealuminium carrier or coalconsists in that the concentrated dicyclohexylamine obtained by amultiple rectification of the reaction mixture is again catalytically hydrogenated on the metal Ru,Pd,Ptor Rhcatalyston the carrier, at the temperature between 80 and 240°Cand pressure between 0.1 and 9.0 MPa,in the same or in other hydrogenation device, whereby above 99.0% w/wconcentrated dicyclohexylamine is obtained.

Description

PROCESS FOR THE PRODUCTION OF HIGHLY PURE DICYCLOHEXYLAMINE FROM BY-PRODUCTS RESULTING FROM THE PRODUCTON OF CYCLOHEXYLAMINE

Field of the Invention

The invention relates to the process for the production of highly pure dicyclohexylannine (DCHA) from by-products resulting from the production of cyclohexylamine (CHA) by hydrogenation of aniline. Dicyclohexylannine is used as an organic chemical, for example also for the production of pesticides and accelerators for vulcanization of rubber with sulphur.

Background of the Invention

Cyclohexylamine is usually produced by catalytic (pressure) hydrogenation of aniline at the increased temperature. Raney cobalt (JP No. 68/03180) or cobalt catalyst with alkaline ingredient (GB pat. No. 969542) are used as catalysts.

Alkali treated ruthenium on neutral carrier as a catalyst of the said hydrogenation is described in US pat. 3 636 108. Ruthenium is used as a catalyst also in DE - AS No. 1 1 06 319, but DCHA resulting at the same time is returned back into the reacion area of aniline hydrogenation in the form of coat of spray (feed). However, this method is characterized by a significant formation of cyclohexane as an idle product of this process. Formation of cyclohexane and other by-products of DCHA synthesis is not cited in DE - C 805518 neither, wherein the process of aniline hydrogenation in vapour phase on nickel catalyst is conducted in such a way, that vapours of the reaction mixture are cooled to a temperature at which DCHA and ammonia with low contents of CHA are condensed therefrom. The ammonia is partially removed from the condensate and the condensate is then sprayed back into the reaction reactor in order to suppress formation of DCHA by means of DCHA : ammonia equilibrium. However, there are no data in this patent about obtaining DCHA in the concentration higher than 88 %. Higher concentrations of the obtained DCHA, up to 94.2 %, are stated in CZ pat. No. 281 499, wherein DCHA at such a high concentration was prepared on a mixed catalyst Ru-Pd, but from aniline and cyclohexanone.

Palladium on the support was used even for hydrogenation of substituted anilines - see EP 53818. However, it was modified by adding metal from the group of alkaline earths, rare earth metals or alkaline coumpounds of alkali metals. The corresponding dicyclohexylamines are not cited, though.

Except for the main product cyclohexylamine, the catalytic hydrogenation of aniline usually always results also in dicyclohexylamine as a by-product, either in gasous or liquid state, as well as several other less abundant intermediate products, including N-cyclohexylidenecyclohexylamine. Therefore, hydrogenation of diphenylamine is preferred to be used for the production of larger amounts of DCHA, e.g. also using ruthenium catalysts on aluminium (DE - AS 1 1 06 319) or from cyclohexylamine and cyclohexanone on Pd/C catalyst (FR 1 333 692).

Separation of N-cyclohexylidenecyclohexylamine from DCHA is commonly carried out by rectification, but effectiveness of this separation is very low, and even impossible below the concentration of 0.6 % w/w (CS AO 241297 B1 ). Therefore, in order to increase the portion of N-cyclohexylidenecyclohexylamine in DCHA, there is used a method of blening its mixture with DCHA with water at a ratio appropriate for making two liquid phases - an organic and water phase. The water hydrolyses N-cyclohexylidenecyclohexylamine in DCHA to cyclohexylamine and cyclohexanone, which change over to a liquid phase. Subsequently, the water phase containing also hydrolytic products is separated from organic phase. Disadvantages of this method comprise low effectiveness of separating the said products and production of waste-water.

According to CS AO 241297B1 the mixture of DCHA and N- cyclohexylidene-cyclohexylamine is also treated with water, but in this case the hydrolysis is combined with distillation in such a way that the boiling mixture of DCHA and N-cyclohexylidene-cyclohexylamine is continually fed by water, hydrolysing N-cyclohexylidene-cyclohexylamine to cyclohexanone and CHA, with which water is then released in the form of vapours, which are after condensation separated from the organic phase. Even though this method, unlike the previous one, does not produce waste water, because the water phase is sprayed back to the distillation step, both methods are characterized in a common disadvantage, namely that half of the N-cyclohexylidenencyclohexylamine molecule is changed into cyclohexanone.

All the above-mentioned methods have one common disadvantage, namely an economically expensive increasing the value of the by. -product CHA and obtaining of DCHA at a low concentration of active ingredient (DCHA), i.e. below 95 % w/w. A possible forming of some precursors of dicyclohexylamine during hydrogenation of aniline is shown in the figure below.

Fig. 1 :

The reaction system of possible forming of some precursors of dicyclohexyl during hydrogenation of aniline without considering the presence of water.

Summary of the Invention

Suprisingly, we have come to a conclusion that after removing cyclohexylamine and the starting aniline from the reaction mixture of aniline hydrogenation in a liquid state, the concentrated DCHA at the concentration almost 98 % w/w of DCHA is obtained as a distillation residuum in a liquid phase, or as a fraction boiling at the highest temperature in case of continual rectification. However, such a concentration is not sufficient for further use of DCHA as a material for subsequent organic syntheses, but neither for industrial productions. If such a source of DCHA, containing precursors of DCHA cited in the previous state of the art, undergoes further rectification on a collumn with a number of layers commonly used in industry, the desired increase in concentration of DCHA is not reached due to the close boiling point, particularly of N-cyclohexylidene- cyclohexylamine, the most abundant DCHA precursor.

The above-mentioned problem is solved by a process for the production of highly pure DCHA during the production of cyclohexylamine by a catalytic hydrogenation of aniline according to the present invention, consisting in that aniline is firstly hydrogenated to CHA and a by-product DCHA. The reaction mixture is subsequently separated by rectification to CHA returning aniline and concentrated DCHA, containing the presursors of dicyclohexylamine, which are after termination of the aniline hydrogenation cycle hydrogenated after a repeated introduction into the same or a different hydrogenation device, where the precursors of DCHA on a metal catalyst (Ru,Pd Pt Rh) convert at the increased temperature and pressure to DCHA with a concentration over 99 % w/w. The precursors of DCHA include for example N-cyclohexylaniline, N-cyclohexylidene- aniline, N-cyclohexylidenecyclohexylamine, N-cyclohexylaminocyclohexene, etc. (see Fig. 1 ), which are changed to the desired dicyclohexylamine by a one- or multi-step hydrogenation. In this way not only decreasing of concentration of impurities practically unseparable even by multiple distillation is reached, but, moreover, the desired active ingredient is obtained therefrom, as they are the precursors of dicyclohexylamine. The concentration of dicyclohexylamine is increased above the value of 99 % w/w in this way, actually in a chemical way, at the increased temperature on a metal catalyst, consisting of Ru, Pd, Pt, Rh on aluminium or coal, at the temperature between 80 and 240 °C and pressure between 0.1 and 9 MPa, without the separation process.

From the point of view of conducting the production of highly pure

dicyclohexylamine, it is most economic to conduct the production in a device for the production of cyclohexylamine from aniline due to identity of catalytic system as well as reaction conditions of hydrogenation of dicyclohexylamine precursors. The fact that highly selective catalysts are usually used in the production of cyclohexylamine from aniline in a liquid phase, resulting in a relatively low production of dicyclohexylamine and other by-products, is a positive aspect.

Therefore, dicyclohexylamine can be processed in a device for production of cyclohexylamine periodically (in batches) once in several months. If the device for aniline hydrogenation consists of two or several hydrogenation reactors connected in a series, hydrogenation of precursors can be conducted in the reactor following the one, in which all aniline is converted. An effective hydrogenation of precursors of dicyclohexylamine can be carried out only in the absence of aniline, the source of forming the precursors.

The examples below further illustrate the present invention without limiting its subject matter.

Examples

E x a m p l e 1 - comparative example

In an experimental production of cyclohexylamine from aniline, catalyzed by a commercially available cca 5 % ruthenium catalyst on alumina a concentrated cyclohexylamine was obtained after separation of the reaction mixture on the head of the first continually operating rectification column. From the following second rectification column mainly aniline returning back into the synthesis was obtained on the head, and from its heel the dicyclohexylamine was obtained, having concentration as cited in Fig. 2, as a coat of spray into the third rectification column with 5 theoretical layers, without an impoverishing part, operating at the pressure of 5 kPa and temperare of 144 ^°C.

Composition of the distillate from the head of the column indicates impossibility of obtaining dicyclohexylamine at a concentration higher than 99.0 % w/w from such a separation. Fig. 2

Review of concentration of input and output dicyclohexylannine from the third rectification column

Contents of DCHA in the input and output of the rectification column

29.X. 3. XI. 8. XI. 13. I. 18. XI. 23. XI. 28.XI. 3. XII.

Date

--a-- inDut —♦— Outout

E x a m p l e 2

200 g of dicyclohexylamine, obtained from the coat of spray into the third column, having the following composition, was introduced into the laboratory high- pressure reactor Parr 4563 with volume of 600 ml:

Coat of spray into the third column Composition

Overall % % w/w

Cyclohexane 0.00

Cyclohexylamine 0.00

Cyclohexanole 0.00

Cyclohexanone 0.00

Aniline 0.00

N-isopropylcyclohexylamine-2H 0.00

N-isopropylaniline-2H 0.00

Unidentified 0.08

Dicyclohexylamine 99.08 98.22

N-cyclohexylidenecyclohexylamine 0.54

N-cyclohexylaniline-2H 0.28

N-cyclohexylaniline 0.03 0.4 g of commercially available ruthenium catalyst containing at least 5 % of Ru on gama aluminium was added. The reactor was washed by hydrogen three times, heated to the temperature of 210 °C and filled with hydrogen under the pressure of 7 MPa. A turbine stirrer set to the rate of stirring 1500 min^"1 was put on. When the hydrogen pressure fell to 5 Mpa, the pressure in the reactor was increased to the value of 7 MPa. The samples were taken at time intervals, apparent from the results of their gaseous-chromatographic analysis cited in the following table:

Hydrogenation Sample 1 Sample 2 Sample 3 Sample 4 Sample 5 of the coat of 30 min 60 min 90 min 120 min 150 min spray into the

third column

Overall W/w Overall W/w Overall W/w Overall W/w Overall W/w

% % % % % % % % % %

Cyclohexane 0.00 0.00 0.00 0.00 0.00

Cyclohexylamine 0.00 0.00 0.00 0.00 0.00

Cyclohexanol 0.00 0.00 0.00 0.00 0.00

Cyclohexanone 0.00 0.00 0.00 0.00 0.00

Aniline 0.16 0.00 0.00 0.00 0.00

N-isopropyl- 0.00 0.00 0.00 0.00 0.00 cyclohexylamine-

2H

N- 0.00 0.00 0.00 0.00 0.00 isopropylaniline- 2H

N-isopropylaniline 0.00 0.00 0.00 0.00 0.00

Unidentified 0.08 0.07 0.06 0.07 0.07

Dicyclohexylami 99.74 99.13 99.90 99.18 99.91 99.26 99.91 99.27 99.89 99.31 ne

N- 0.04 0.02 0.02 0.02 0.04 cyclohexylidene- cyclohexylamine

N- 0.00 0.00 0.00 0.00 0.00 cyclohexylaniline- 2H

N- 0.00 0.00 0.00 0.00 0.00 cyclohexylaniline It is obvious from the above results, that already after 30 minutes of hydrogenation the concentration of dicyclohexylamine reached the value of 99.0 % w/w.

E x a m p l e 3

In the reactor as in Example 2 was hydrogenated the same sample of dicyclohexylamine as in Example 2, taken from the pump P 624 17/12/2009, at the hydrogen pressure of 6 MPa and under reaction conditions cited in the first column. The following results were obtained:

Composition of reaction mixture

Identification Overall N-cyclo- N- N- of the consumpSample DCHA

hexylidene cyclohexyl- cyclohexyl- experiment/ tion of H₂ No./T

cyclohexylmine aniline-2H aniline batch (MPa) [min.] % %

overall % overall % overall % overall w/w

6/180 99.90 99.57 0.03 0.00 0.00

1/30 99.34 98.59 0.22 0.20 0.07

DCHA 2/60 99.46 98.70 0.19 0.16 0.08 118/09

0.4 g cat.

5% Ru on 3/90 99.60 98.84 0.10 0.10 0.10 AI203, 1.20

200 g DCHA 4/120 99.68 98.92 0.07 0.06 0.06 from P 624

17.12.2009;

T 100 °c 5/150 99.73 98.98 0.04 0.04 0.1 1

6/180 99.41 98.66 0.04 0.00 0.10

E x a m p l e 4

In the reactor as in Example 2 was hydrogenated the same sample of dicyclohexylamine as in Example 2, taken from the pump P 624 4/01/2010, at the hydrogen pressure of 6 MPa and under reaction conditions cited in the first column. The following results were obtained:

Composition of reaction mixture

Identification Overall Sample

N- of the consumpNo./T DCHA N-cyclo- N- cyclohexyl- experiment/ tion of H₂ [min.] hexylidene cyclohexyl- aniline batch (MPa)

% % cyclohexylmine aniline-2H

overall % overall w/w overall % overall %

AI203,

3/90 98.96 98.13 0.44 0.39 0.08

200 g DCHA

from P 624 4/120 98.90 97.89 0.43 0.42 0.10 04/01/2010;

80 °C

5/150 98.98 98.14 0.217 0.34 0.09

6/180 99.07 98.17 0.39 0.33 0.10

1/30 98.91 97.83 0.43 0.43 0.06

DCHA 2/60 98.93 97.91 0.43 0.40 0.07 122/10

0.4 g cat.

5% Ru on 3/90 98.94 97.97 0.41 0.39 0.08 AI203, 1.30

200 g DCHA 4/120 98.99 97.78 0.38 0.38 0.08 from P 624

04/01/2010;

90 °C 5/150 99.10 97.83 0.28 0.35 0.09

6/180 99.16 98.06 0.24 0.33 0.10

E x a m p l e 5

In the reactor as in Example 2 was hydrogenated the same sample of dicyclohexylamine as in Example 2, taken from the pump P 624 1 1/01/2010 and 25/01/2010, at the hydrogen pressure of 6 MPa and under reaction conditions cited in the first column. The following results were obtained:

P 624 1 1/01/2010

Composition of reaction mixture

Identification Overall

Sample N-cyclo- N- N- of the consump¬

No./T DCHA hexylidene cyclohexyl- cyclohexyl- experiment/ tion of H₂

[min] cyclohexylmine aniline-2H aniline batch (MPa)

% % overall % overall % overall % overall w/w

DCHA from

P 624 99.25 98.38 0.37 0.21 0.05

1 1/01/2010; Composition of reaction mixture

Identification Overall

Sample N-cyclo- N- N- of the consump¬

No./T DCHA hexylidene cyclohexyl- cyclohexyl- experiment/ tion of H₂

[min] cyclohexylmine aniline-2H aniline batch (MPa)

% % overall % overall % overall % overall w/w

1/30 99.72 98.61 0.05 0.02 0.08

DCHA

123/10 2/60 99.81 98.80 0.03 0.00 0.04

0.4 g cat.

5% Ru on

AI203, 3/90 99.83 98.63 0.03 0.01 0.00 pH₂=6MPa 1.45

200 g DCHA 4/120 99.85 98.70 0.02 0.00 0.01 from P 624

11/01/2010;

T 5/180 99.85 98.63 0.03 0.00 0.00

120 °C

6/240 99.84 98.98 0.03 0.00 0.00

1/30 99.56 99.04 0.03 0.02 0.23

DCHA

124/10 2/60 99.57 99.01 0.03 0.00 0.24

0.4 g cat.

5% Pd/C:

3/90 99.57 99.02 0.03 0.00 0.24 pH₂=6MPa,

1.20

200 g DCHA

from P 624 4/120 99.53 98.93 0.02 0.00 0.24 11/01/2010;

T 5/180 99.60 99.15 0.02 0.00 0.23

120 °C

6/240 99.57 99.06 0.02 0.00 0.22

1/30 99.65 99.03 0.03 0.04 0.12

DCHA

125/10 2/60 99.67 99.10 0.03 0.02 0.12

0.4 g cat.

5% Rh/C;

3/90 99.64 99.08 0.03 0.01 0.10 pH₂=6MPa,

1.10

200 g DCHA

from P 624 4/120 99.67 99.10 0.02 0.01 0.10 11/01/2010;

T 5/180 99.68 99.13 0.02 0.00 0.08

120 °C

6/240 99.69 99.13 0.02 0.00 0.07

DCHA 1/30 99.73 99.14 0.02 0.00 0.05 126/10

0.4 g cat. 2/60 99.76 99.17 0.02 0.00 0.02

5% Ru/C;,

pH₂=9MPa, 3/90 99.77 99.19 0.02 0.00 0.01 200 g DCHA

from P 624 0.65 4/120 99.78 99.19 0.02 0.00 0.01 11/01/2010;

T 150 °C 5/180 99.77 99.17 0.02 0.00 0.00 Composition of reaction mixture

Identification Overall

Sample N-cyclo- N- N- of the consump¬

No./T DCHA hexylidene cyclohexyl- cyclohexyl- experiment/ tion of H₂

[min] cyclohexylmine aniline-2H aniline batch (MPa)

% % overall % overall % overall % overall w/w

6/240 99.79 99.21 0.02 0.00 0.00

1/30 99.56 99.05 0.03 0.00 0.24

DCHA

127/10 2/60 99.58 99.19 0.02 0.00 0.24

0.4 g cat.

5% Pt/C,

3/90 99.59 99.22 0.02 0.00 0.24 pH₂=3MPa,

0.65

200 g DCHA

4/120 99.59 99.25 0.03 0.00 0.23 from P 624.:

11/01/2010;

T 5/180 99.49 99.19 0.02 0.00 0.23

150 °C

6/240 99.58 99.23 0.02 0.00 0.23

1/30 99.56 99.16 0.08 0.00 0.13

2/60 99.64 99.22 0.06 0.00 0.28

DCHA

128/10

0.4 g cat. 3/120 66.62 99.21 0.05 0.00 0.02 5% Ru/C

200 g DCHA 0.05 4/180 99.59 99.17 0.06 0.00 0.02 from P 624

11/01/2010; 5/240 99.54 99.09 0.05 0.00 0.02 0,5 MPa;

T 240 °C

6/300 99.45 99.06 0.05 0.00 0.02

7/360 99.43 99.01 0.05 0.00 0.01

P 624 25/0 /2010

Composition of reaction mixture

Identification Overall N-cyclo- N- N- of the consumpSample

DCHA hexylidene cyclohexyl- cyclohexyl- experiment/ tion of H₂ No./T

cyclohexylmine aniline-2H aniline batch (MPa) [min]

% % overall % overall % overall % overall w/w

DCHA from

P 624 of 97.54 97.34 0.57 1.51 0.29

25/01/2010

DCHA

1/30 99.62 99.49 0.05 0.00 0.17 133/10

0.4 g cat.

2/60 99.76 99.58 0.04 0.00 0.03 5% Ru on

1 ,05

AI203

3/90 99.67 99.49 0.03 0.00 0.01 200 g DCHA

from P 624 of

4/120 97.90 97.73 0.04 0.00 0.00 25/01/2010 Composition of reaction mixture

Identification Overall N-cyclo- N- N- of the consumpSample

DCHA hexylidene cyclohexyl- cyclohexyl- experiment/ tion of H₂ No./T

cyclohexylmine aniline-2H aniline batch (MPa) [min]

% % overall % overall % overall % overall w/w

5/180 99.82 99.75 0.01 0.00 0.00

7.0 - 5.0

MPa;

6/240 99.83 99.74 0.02 0.00 0.00 150 °C

DCHA

1/30 99.73 99.35 0.03 0.00 0.00 134/10

0.4 g cat.

2/60 99.76 99.38 0.03 0.00 0.00 5% Ru on

AI203

3/90 99.78 99.47 0.04 0.00 0.00

200 g DCHA

1 , 10 4/120 99.79 99.51 0.02 0.00 0.00 from P 624

of:

5/180 99.76 99.51 0.03 0.00 0.00

25/01/2010

7.0 - 5.0

MPa; 6/240 99.79 99.62 0.04 0.00 0.00 180 °C

0 87.65 86.22 0.52 0.00 0.05

DCHA

135/10

0,27 g cat. 1/30 92.28 90.81 0.03 0.00 0.06 5% Ru on

AI203

2/60 92.09 91.1 13 0.06 0.00 0.04

136 g DCHA

from P 624 of

0,3 3/90 92.02 90.76 0.03 0.00 0.03 25/01/2010

13,6 g CHA 4/120 92.20 91.17 0.02 0.00 0.02 of

20.08.2009;

7.0 - 5.0 5/180 92.74 91.56 0.03 0.00 0.00 MPa;

150 °C

6/240 92.05 90.93 0.04 0.00 0.00

Experiments DCHA133 and 134 from Example 5 evidence precursors' ability also at their high or even boundary concentration.

Experiment 135 from this example by means of a very low residual concentration of the sum of precursors evidences the fact, that hydrogenation is conducted also at the presence of cyclohexylamine, which can be easily removed from

dicyclohexylamine by distillation, and thus the desired concentration of

dicyclohexylamine above 99 % w/w can be reached. E x a m p l e 6

After terminating the production cycle of cyclohexylamine from aniline, catalysed by 5 % ruthenium catalyst on aluminium, dosing of aniline into the experimental operating device was stopped and cyclohexylamine was removed in such a way, that only dicyclohexylamine, the composition of which is represented by a sample from the pump P 624 of 1 1/01/2010 and a recycled catalyst started to be sprayed. After heating the reactor to the temperature of 150 °C, at the hydrogen flow rate of 1500 m³/h and pressure of 6 Mpa, and after reaching the dicyclohexylamine concentration above 99.1 % w/w, the product of the reaction mixture started to be taken during spraying of dicyclohexylamine 300 l/h for the final treatment by distillation - redistillation after hydrogenation of precursors.

Claims

C L A I M S

1 . Process for the preparation of highly pure dicyclohexylannine from by-products resulting from the production of cyclohexylamine by hydrogenation of aniline in a liquid phase on ruthenium catalyst, characterized in that after separation of cyclohexylamine, the fraction of concentrated dicyclohexylannine with its precursors, or residues of cyclohexylamine, is catalytically hydrogenated at the increased temperature and pressure, until reaching the concentration of dicyclohexylannine above 99 % w/w.

2. Process according to claim 1 , characterized in that the precursor of

dicyclohexylannine is N-cyclohexylaniline, N-cyclohexylideneaniline, N- cyclohexylidenecyclohexylamine and N-cyclohexylamino-cyclohexene.

3. Process according to claim 1 , characterized in that the catalytic

hydrogenation is conducted at the temperature between 80 and 240 °C.

4. Process according to claim 1 , characterized in that the catalytic

hydrogenation is conducted at the pressure between 0.1 and 9 MPa.

5. Process according to any of claims 1 to 4, characterized in that the catalyst is ruthenium, palladium, platinum or rhodium on aluminium or coal.

6. Process according to any of claims 1 to 5, characterized in that the catalytic hydrogenation is conducted in a device for the production of cyclohexylamine.

7. Process according to any of claims 1 to 6, characterized in that that the catalytic hydrogenation is conducted in a device connected after the line for hydrogenation of aniline.

8. Process according to any of claims 1 to 4, characterized in that the catalytic hydrogenation is conducted in a separate device.