SK288006B6 - Method for producing highly pure dicyclohexylamine from by-products of cyclohexylamine - Google Patents

Abstract

Method for producing highly pure dicyclohexylamine in the manufacture cyclohexylamine from aniline in its liquid phase at the ruthenium catalyst on a support of alumina and carbon is that the multiple rectification reaction mixture obtained by concentrate dicyclohexylamine is repeatedly on the metal Ru, Pd, Pt or Rh catalyst on a carrier, the temperature 80 to 240 ° C and a pressure from 0,1 to 9,0 MPa is hydrogenate to obtain the product having a purity of more than 99.0% by weight.

Description

Technical field

The invention relates to a process for the production of high purity dicyclohexylamine (DCHA) from by-products resulting from the production of cyclohexylamine (CHA) by hydrogenation of aniline. Dicyclohexylamine is also used as an organic chemical also for the production of pesticides and accelerators of sulfur vulcanization of rubbers.

BACKGROUND OF THE INVENTION

Cyclohexylamine is usually prepared by catalytic (pressure) hydrogenation of aniline at elevated temperature. Raney cobalt (JP No. 68/03180) or a cobalt catalyst with a basic additive (GB Pat. No. 969542) is used as the catalyst.

Alkaline treated ruthenium on a neutral support as a catalyst for the subject hydrogenation is described in US Pat. In DE - AS no. Ruthenium is also used as a catalyst, but the concomitant DCHA is returned in the feed to the aniline hydrogenation reaction area. However, this process is characterized by the significant formation of cyclohexane as a loss product of the process. The formation of cyclohexane and other by-products of the synthesis of DCHA is also not disclosed in DE-C 805518, where the steam-phase aniline hydrogenation process on a nickel catalyst is conducted by cooling the reaction mixture vapors to a temperature at which DCHA and ammonia condense. low CHA. The ammonia is partially removed from the condensate and the condensate is subsequently injected back into the hydrogenation reactor to suppress the formation of DCHA through the DCHA: ammonia equilibrium. However, none of the disclosures suggest that DCHA would be obtained at a concentration greater than 88%.

Higher concentrations of the obtained DCHA, up to 94.2%, are given in CZ Pat. no. 281 499, where DCHA was prepared at such a high concentration on a mixed Ru-Pd catalyst but from aniline and cyclohexanone.

The supported palladium was even used to hydrogenate substituted anilines - see EP 53818. However, it was modified by the addition of an alkaline earth metal, a rare earth metal or a basic alkali metal compound. However, the corresponding dicyclohexylamines are not disclosed.

In the catalytic hydrogenation of aniline, in the gaseous or liquid phase, in addition to the main cyclohexylamine product, dicyclohexylamine is in most cases also formed as a by-product and a number of other less represented intermediates including N-cyclohexylidene-cyclohexylamine. Hence, hydrogenation of diphenylamine, e.g. also using ruthenium catalysts on alumina (DE-AS 11 06 319) or cyclohexylamine and cyclohexanone on a Pd / C catalyst (FR 1 333 692).

The separation of N-cyclohexylidene-cyclohexylamine from DCHA is normally carried out by rectification, but the efficiency of this separation is very low and below 0.6% by weight. practically unrealistic (CS AO 241297 BI). Therefore, in order to further reduce the proportion of N-cyclohexylidene-cyclohexylamine in DCHA, a process is used in which its mixture with DCHA is mixed with water in such a proportion as to form two liquid phases - organic and aqueous. Water hydrolyzes N-cyclohexylidene-cyclohexylamine in DCHA to cyclohexylamine and cyclohexanone, which pass into the aqueous phase. Subsequently, the aqueous phase, containing the hydrolytic products, is separated from the organic phase. The disadvantage of this procedure is the low efficiency of the separation of the products in question and the production of waste water.

According to CS AO 241297B1, a mixture of DCHA and N-cyclohexylidene-cyclohexylamine is also treated with water, except that a combination of hydrolysis and distillation is combined here by continuously feeding the boiling mixture of DCHA and N-cyclohexylidene-cyclohexylamine to N-cyclohexylidene-cyclohexylamine with which the water then leaves in the form of vapors which, after the condensation, separate from the organic phase. Although this process does not produce waste water, as the aqueous phase is re-injected into the distillation step, they both have the same disadvantage that the half of the N-cyclohexylidene-cyclohexylamine molecule is converted to cyclohexanone.

A common disadvantage of all these processes is the costly recovery of the byproduct of CHA production and the recovery of DCHA in a low concentration of active ingredient (DCHA) - below 95% by weight. Possible formation of some dicyclohexylamine precursors in aniline hydrogenation is illustrated in the accompanying scheme of the reaction system for the possible formation of some dicyclohexylamine precursors in aniline hydrogenation without considering the presence of water.

SUMMARY OF THE INVENTION

We have surprisingly concluded that, after removal of cyclohexylamine and the starting aniline from the aniline hydrogenation reaction mixture in the liquid phase, a concentrated DCHA of almost 98% by weight is obtained as the distillation residue or, in the case of continuous rectification, as the highest boiling fraction. DCHA. However, such a concentration is insufficient for further use of DCHA as a raw material for subsequent organic syntheses, but also for industrial production. If such a DCHA source containing the prior art DCHA precursors is subjected to further rectification on a tray with a number of trays commonly used in industry, the desired increase in DCHA concentration due to the near boiling point of particularly the most widely contained DCHA precursor N-cyclohexylidenecene is not achieved.

The problem is solved by a process for producing high purity DCHA in the production of cyclohexylamine by catalytic hydrogenation of aniline according to the present invention, characterized in that aniline is first hydrogenated to CHA and the by-product DCHA. The reaction mixture is then separated by rectification into CHA return aniline and concentrated DCHA containing dicyclohexylamine precursors, which upon hydrogenation of the aniline hydrogenation cycle are hydrogenated upon re-introduction into one or other hydrogenation equipment where the precursors

DCHA on a metal catalyst (Ru, Pd Pt Rh) at elevated temperature and pressure converts to DCHA at a concentration above 99% by weight. DCHA precursors include, for example, N-cyclohexylaniline, N-cyclohexylideaaniline, N-cyclohexylidene-cyclohexylamine, N-cyclohexylaminocyclohexene and others (see Figure 1), which are converted to the desired dicyclohexylamine by one or more stages of hydrogenation. In this way, not only is the concentration of impurities practically inseparable by multiple distillation reduced, but, since they are precursors of dicyclohexylamine, the desired active substance is obtained. In fact, such a process increases the dicyclohexylamine concentration at 80 DEG to 240 DEG C. and at a pressure of 0.1 to 9 MPa at elevated temperature on a metal catalyst consisting of Ru, Pd, Pt, Rh on alumina or coal, without a separation process. % above 99 wt.

From the aspect of realizing the production of high purity dicyclohexylamine, it is most economical to produce it in a cyclohexylamine production plant from aniline because of the identity of the use of the catalyst system and the reaction conditions of hydrogenation of dicyclohexylamine precursors. A positive aspect is also the fact that in the production of cyclohexylamine from aniline in the liquid phase, highly selective catalysts are mostly used, which results in a relatively low production of dicyclohexylamine and other by-products. Therefore, dicyclohexylamine can be processed in a batch process every several months on a cyclohexylamine production plant. If the aniline hydrogenation device consists of two or more sequentially connected hydrogenation reactors, the hydrogenation of the precursors can be carried out in a reactor following the reactor in which all the aniline is converted. A condition for effective hydrogenation of dicyclohexylamine precursors is the absence of a precursor formation source, aniline.

BRIEF DESCRIPTION OF THE DRAWINGS

In FIG. 1 shows an overview of the concentrations of input and output dicyclohexylamine from the third rectification column.

The examples below illustrate but do not limit the scope of the claimed invention.

DETAILED DESCRIPTION OF THE INVENTION

Example 1 - Comparative

In the experimental production of cyclohexylamine from aniline, catalyzed by a commercially available about 5% ruthenium catalyst on alumina, concentrated cyclohexylamine was obtained after separation of the reaction mixture at the top of the first continuously working rectification column. From the subsequent second rectification column, mainly aniline was recovered on the top, returning to the synthesis, and dicyclohexylamine, the concentration of which is shown in FIG. 2 as a feed into a third rectification column with 5 theoretical plates, without a depleting section, operating at a pressure of 5 kPa and a temperature of 144 ° C.

The composition of the distillate from the top of this column documents the impossibility of obtaining dicyclohexylamine at a concentration of more than 99.0% by weight. from such a separation.

Example 2

Into a 600 ml Parr 4563 high pressure laboratory reactor was charged 200 g of dicyclohexylamine obtained from the feed into a third column having the following composition:

Injection to the third column composition Area% Weight. % cyclohexane 0.00 cyclohexylamine 0.00 cyclohexanol 0.00 cyclohexanone 0.00 aniline 0.00 N-isopropyl cyclohexyl-2 H 0.00 N-isopropylaniline-2H 0.00 Neidetifikovaná 0.08 dicyclohexylamine 99.08 98.22 N-cyklohex.ylidencyklohexylamin 0.54 N-cyclohexylaniline-2H 0.28 N-cyclohexylaniline 0.03

0.4 g of a commercially available ruthenium catalyst containing at least 5% Ru per gamma alumine was added. Purge reactor three times with hydrogen, warmed to 210 ° C, and pressurized with hydrogen to 7 MPa .. To date, the said turbine rotating on the intensity of agitation 1500 rpm ^first As the hydrogen pressure dropped to 5 MPa, the reactor was pressurized to 7 MPa. Samples were taken over time intervals, evident from the results of their gas-chromatographic analysis given in the table below:

Hydrogenation of feed to the third column vz. 1 30 min. vz. 2 60 min. vz. 3 90 min. vz. 4 120 min. vz. 5,150 min. Desktop. % Weight. % Desktop. % Weight. % Desktop. % Weight. % Desktop. % Weight. % Desktop. % Weight. % 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-cyclo- 2H-hexylamine 0.00 0.00 0.00 0.00 0.00 N-isopropylaniline-2H 0.00 0.00 0.00 0.00 0.00 N-isopropylaniline 0.00 0.00 0.00 0.00 0.00 unidentified 0.08 0.07 0.06 0.07 0.07 dicyclohexylamine 99.74 99.13 99.90 99.18 99.91 99.26 99.91 99,27 99.89 99.31 N-cyclohexylidene cyclohexylamine 0.04 0.02 0.02 0.02 0.04 N-cyclohexylaniline-2H 0.00 0.00 0.00 0.00 0.00 N-cyclohexylaniline 0.00 0.00 0.00 0.00 0.00

From the results it can be seen that after 30 minutes of hydrogenation the dicyclohexylamine concentration reached 99.0% by weight.

Example 3

In the reactor as in Example 2, the same dicyclohexylamine sample as in Example 2, taken from the P 624 pump on 17.12.2009, was hydrogenated at a hydrogen pressure of 6 MPa and under the reaction conditions of the first column. The following results were obtained:

Experiment / tool set Total consumption H ₂ (MPa) Sample. no. / T [Min.] Composition of the reaction mixture DCHA N-cyclohexylidene cyclohexylmin pl. % N-cyclohexyl-anilin2Hpl. % N-cyclo- hexyl aniline pl.% % Full. % weight. DCHA from P-624 from 17.12.2009) 99.08 98.22 0.54 0.28 0.03 P 624/2 0.4 g cat. 5% Ru on AI2O3, 200 g DCHA from P 624 from 17.12.2009 Mp 180 ° C 0.60 1/10 99.92 99.10 0.02 0.00 0.00 2/30 99.91 99.32 0.17 0.00 0.00 3/60 99.90 99,42 0.02 0.00 0.00 4/90 99.91 99,39 0.03 0.00 0.00 DCHA 117/09 0.4 g cat. 5% Ru to A12O3, 200 g DCHA from P 624 from 17.12.2009 T 150 [deg.] C 1.00 1/30 99.90 99.32 0.03 0.00 0.00 2/60 99.90 99.68 0.04 0.00 0.00 3/90 99.90 99.71 0.02 0.00 0.00 4/120 99.79 99.57 0.03 0.00 0.00 5/150 99.89 99.63 0.03 0.00 0.00 6/180 99.90 99.57 0.03 0.00 0.00

Labeling attempt. / handle Total consumption H ₂ (MPa) Sample. No. / T [Min.] Composition of the reaction mixture DCHA N-cyclohexylidene cyclohexylmin pl. % N-cyclohexyl-aniline2H pl. % N-cyclohexyl-aniline pl. % % pl. % weight. DCHA 118/09 0.4 g cat. 5% Ru on AI2O3, 200 g DCHA from P 624 17.12.2009; T 100 ° C 1.20 1/30 99.34 98,59 0.22 0.20 0.07 2/60 99.46 98.70 0.19 0.16 0.08 3/90 99.60 98.84 0.10 0.10 0.10 4/120 99.68 98.92 0.07 0.06 0.06 5/150 99.73 98.98 0.04 0.04 0.11 6/180 99.41 98.66 0.04 0.00 0.10

Example 4

In the reactor as in Example 2, a sample of dicyclohexylamine as in Example 2, taken from a 5 pump P 624 04/01/2010, was hydrogenated at a hydrogen pressure of 6 MPa and under the reaction conditions given in the first column.

The following results were obtained:

Experiment / Tooltip Total consumption H ₂ (MPa) Sample. no. / T [Min.] Composition by reaction mixtures DCHA N-cyclohexylidene cyclohexylmin pl. % N-cyclohexyl-aniline-2H pl. % N-cyclohexyl-aniline pl. % % pl % weight. DCHAz P 624 04.01.2009) 98.91 97.51 0.48 0.43 0.06 DCHA 119/09 0.4 g cat. 5% Ru to A12O3, 200 g DCHA from P 624 04.01.2010; 80 ° C 1.05 1/30 98.84 98.12 0.50 0.45 0.07 2/60 98.94 98.25 0.45 0.40 0.07 3/90 98.96 98.13 0.44 0.39 0.08 4/120 98.90 97.89 0.43 0.42 0.10 5/150 98.98 98.14 0,217 0.34 0.09 6/180 99.07 98,17 0.39 0.33 0.10 DCHA 122/10 0.4 g cat. 5% Ru to A12O3, 200 g DCHA from P 624 04.01.2010; 90 ° C 1.30 1/30 98.91 97.83 0.43 0.43 0.06 2/60 98,93 97.91 0.43 0.40 0.07 3/90 98.94 97.97 0.41 0.39 0.08 4/120 98.99 97.78 0.38 0.38 0.08 5/150 99.10 97.83 0.28 0.35 0.09 6/180 99.16 98.06 0.24 0.33 0.10

Example 5

In the reactor as in Example 2, a sample of dicyclohexylamine as in Example 2, taken from the P 624 pump 11.01.2010 and 25.01.2010, was hydrogenated under hydrogen pressure and other reaction conditions set forth in the first column. The following results were obtained:

P 624 11.01.2010

Experiment / Handle label Total consumption h ₂ (MPa) Sample. No. / T [min] Composition of the reaction mixture DCHA N-cyclohexylidene cyclohexylmin pl. % N-cyclohexyl-aniline2H pl. % N-cyclohexyl-aniline pl. % pl% weight. % DCHA from P 624 11.01.2010; 99.25 98.38 0.37 0.21 0.05 DCHA 123/10 0,4 g cat. 5% Ru to Al ₂ O 3, pH ₂ = 6MPa 200 g DCHA from P 624 11.01.2010; Mp 120 ° C 1.45 1/30 99.72 98.61 0.05 0.02 0.08 2/60 99.81 98.80 0.03 0.00 0.04 3/90 99.83 98,63 0.03 0.01 0.00 4/120 99.85 98.70 0.02 0.00 0.01 5/180 99.85 98,63 0.03 0.00 0.00 6/240 99.84 98.98 0.03 0.00 0.00

Experiment / Handle label Total consumption h ₂ (MPa) Sample. No. / T [min] Composition of the reaction mixture DCHA N-cyclohexylidene cyclohexylmin pl. % N-cyclohexyl-aniline2H pl. % N-cyclohexyl-aniline pl. % pl% weight. % DCHA 124/10 0,4 g cat. 5% Pd / C: pH ₂ = 6MPa, 200 g DCHA from P 624 11.01.2010; Mp 120 ° C 1.20 1/30 99.56 99.04 0.03 0.02 0.23 2/60 99.57 99.01 0.03 0.00 0.24 3/90 99.57 99.02 0.03 0.00 0.24 4/120 99.53 98,93 0.02 0.00 0.24 5/180 99.60 99.15 0.02 0.00 0.23 6/240 99.57 99.06 0.02 0.00 0.22 DCHA 125/10 0,4 g cat. 5% Rh / C; pH ₂ = 6MPa, 200 g DCHA from P 624 11.01.2010; Mp 120 ° C 1.10 1/30 99.65 99.03 0.03 0.04 0.12 2/60 99.67 99.10 0.03 0.02 0.12 3/90 99.64 99.08 0.03 0.01 0.10 4/120 99.67 99.10 0.02 0.01 0.10 5/180 99.68 99.13 0.02 0.00 0.08 6/240 99.69 99.13 0.02 0.00 0.07 DCHA 126/10 0,4 g cat. 5% Ru / Cl, pH ₂ = 9MPa, 200 g DCHA from P 624 11.01.2010; Mp 150 ° C 0.65 1/30 99.73 99.14 0.02 0.00 0.05 2/60 99.76 99.17 0.02 0.00 0.02 3/90 99.77 99.19 0.02 0.00 0.01 4/120 99.78 99.19 0.02 0.00 0.01 5/180 99.77 99.17 0.02 0.00 0.00 6/240 99.79 99.21 0.02 0.00 0.00 DCHA 127/10 0,4 g cat. 5% Pt / C, pH ₂ = 3MPa, 200g DCHA from P 624: January 11, 2010; Mp 150 ° C 0.65 1/30 99.56 99.05 0.03 0.00 0.24 2/60 99.58 99.19 0.02 0.00 0.24 3/90 99.59 99.22 0.02 0.00 0.24 4/120 99.59 99.25 0.03 0.00 0.23 5/180 99.49 99.19 0.02 0.00 0.23 6/240 99.58 99,23 0.02 0.00 0.23 DCHA 128/10 0.4 g cat. 5% Ru / C 200 g DCHA from P 624 11.01.2010; 0.5 MPa; Mp 240 ° C 0.05 1/30 99.56 99.16 0.08 0.00 0.13 2/60 99.64 99.22 0.06 0.00 0.28 3/120 66.62 99.21 0.05 0.00 0.02 4/180 99.59 99.17 0.06 0.00 0.02 5/240 99.54 99.09 0.05 0.00 0.02 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 25.01.2010

experimental / tool set Total consumption H ₂ (MPa) Sample. no. / T [Min.] Composition of the reaction mixture DCHA N-cyclohexylidene cyclohexylmin pl. % N-cyclohexylaniline-2H pl. % N-cyclohexyl-aniline pl. % % pl. % weight. DCHA from P 624 z25.01.2010 97.54 97.34 0.57 1.51 0.29 DCHA 133/10 0.4 g cat. 5% Ru to A12O3 200 g DCHA from P 624 from 25.01.2010 7.0 - 5.0 MPa; 150 [deg.] C 1.05 1/30 99.62 99.49 0.05 0.00 0.17 2/60 99.76 99.58 0.04 0.00 0.03 3/90 99.67 99.49 0.03 0.00 0.01 4/120 97.90 97,73 0.04 0.00 0.00 5/180 99.82 99.75 0.01 0.00 0.00 6/240 99.83 99.74 0.02 0.00 0.00

experimental / tool set Total consumption H ₂ (MPa) Sample. no. / T [Min.] Composition of the reaction mixture DCHA N-cyclohexylidene cyclohexylmin pl. % N-cyclohexylaniline-2H pl% N-cyclo- cyclohexyl-aniline pl.% % pl. % weight. DCHA 134/10 1/30 99.73 99.35 0.03 0.00 0.00 0.4 g cat. 2/60 99.76 99.38 0.03 0.00 0.00 5% Ru to 3/90 99.78 99.47 0.04 0.00 0.00 A12O3 4/120 99.79 99.51 0.02 0.00 0.00 200 g DCHA from P 624 from: 25.01.2010 7.0-5.0 MPa; Mp 180 ° C 1.10 5/180 99.76 99.51 0.03 0.00 0.00 6/240 99.79 99.62 0.04 0.00 0.00 DCHA 135/10 0 87.65 86.22 0.52 0.00 0.05 0.27 g cat. 1/30 92.28 90.81 0.03 0.00 0.06 5% Ru to 2/60 92.09 91.113 0.06 0.00 0.04 A12O3 3/90 92,02 90.76 0.03 0.00 0.03 136 g DCHA 4/120 92.20 91.17 0.02 0.00 0.02 0.3 5/180 92.74 91.56 0.03 0.00 0.00 from P 624 of 25.01.2010 13.6 g CHA from 20.08.2009; 7.0 - 5.0 MPa; 150 [deg.] C 6/240 92.05 90.93 0.04 0.00 0.00

Experiments DCHA133 and 134 of Example 5 demonstrate the ability to hydrate the precursors even at their high to limit concentrations.

Experiment 135 of this example, by means of a very low residual concentration of the sum of precursors, demonstrates the fact that hydrogenation is also carried out in the presence of cyclohexylamine, which can easily be removed from the dicyclohexylamine by distillation and thereby achieve the desired dicyclohexylamine concentration above 99% by weight.

Example 6

After the end of the cyclohexylamine production cycle from aniline catalyzed by 5% ruthenium catalyst on alumina, the aniline feed was stopped and the cyclohexylamine was removed by injecting only dicyclohexylamine, the composition of which is represented by the sample from pump P 624 of 11.01.2010 and recycled catalyst. After the reactor has been allowed to reach 150 ° C, a hydrogen flow rate of 1500 m ³ / h and a pressure of 6 MPa and a dicyclohexylamine concentration above 99.1% by weight has been reached. the product of the reaction mixture was started to be withdrawn at the dicyclohexylamine feed rate of 300 l / h for finalization by distillation - distillation after hydrogenation of the precursors.

Claims (8)

Process for the production of high purity dicyclohexylamine from by-products of cyclohexylamine production by hydrogenation of aniline in a liquid phase on a ruthenium catalyst, characterized in that after separation of cyclohexylamine, the fraction of concentrated dicyclohexylamine with its precursors, optionally with cyclohexylamine residues, is increased; to a dicyclohexylamine concentration above 99 wt. 2. The process of claim 1 wherein the dicyclohexylamine precursor is N-cyclohexylaniline, N-cyclohexylidenaniline, N-cyclohexylidecyclohexylamine and N-cyclohexylaminocyclohexene. Process according to claim 1, characterized in that the catalytic hydrogenation is carried out at a temperature of 80 to 240 ° C. Process according to claim 1, characterized in that the catalytic hydrogenation is carried out at a pressure of from 1 to 9 MPa. Process according to any one of claims 1 to 4, characterized in that the catalyst is ruthenium, palladium, platinum or radium on alumina or coal. Process according to any one of claims 1 to 5, characterized in that the hydrogenation is carried out in a cyclohexylamine production plant. Method according to any one of claims 1 to 6, characterized in that the hydrogenation is carried out in a device connected downstream of the aniline hydrogenation line. Process according to any one of claims 1 to 4, characterized in that the hydrogenation is carried out in a separate device. that catalytic that catalytic that catalytic