Process For Preparing Amino Compounds From Nitrile Compounds

Abstract

The present invention relates to a process for hydrogenating nitrile compounds to amino compounds, in which the cross-sectional loading of the reactor during the hydrogenation is less than or equal to 4.0 kg/m.sup.2*s, based on the liquid phase.

Claims

1. A process for hydrogenating nitrile compounds to amino compounds, wherein the cross-sectional loading of the reactor during the hydrogenation is less than or equal to 4.0 kg/m.sup.2*s, based on the liquid phase.

2. The process according to claim 1, wherein the nitrile compound is selected from the group consisting of a mixture of 2,4,4-trimethylhexamethylenedinitrile and 2,2,4-trimethylhexamethylenedinitrile and b) isophoronenitrile or isophoronenitrile imine is used.

3. The process according to claim 1, wherein isophoronenitrile is subjected to aminating hydrogenation to give isophoronediamine.

4. The process according to claim 3, wherein A) isophoronenitrile is subjected directly in one stage to aminating hydrogenation to give isophoronediamine in the presence of ammonia, hydrogen, a catalyst and possibly further additions, and in the presence or absence of organic solvents; or B) isophoronenitrile is reacted in at least two stages, wherein said isophoronenitrile in initially converted in a first stage entirely or partly to isophoronenitrile imine which, as a pure substance or in a mixture with other components and possibly unreacted isophoronenitrile, is hydrogenated in at least one subsequent stage to give isophoronediamine in the presence of at least ammonia, hydrogen and a catalyst.

5. The process according to claim 1, wherein the cross-sectional loading is from 0.01 to 4.0 kg/m.sup.2*s.

6. The process according claim 1, wherein the ratio of circulation stream to the feedstock stream supplied is in the range from 0:1 to 0.49:1.

7. The process according any claim 1, wherein the hydrogenation is carried out at temperatures between 20 and 150 C. and pressures of from 0.3 to 50 MPa.

8. The process according to claim 3, wherein the process for preparing isophoronediamine is carried out in two or more stages and in that isophoronenitrile is converted in a first stage to isophoronenitrile imine by reaction with ammonia in the presence or absence of an imination catalyst or solvent.

9. The process according to claim 8, wherein the reaction product of the first stage is hydrogenated in the presence of at least one hydrogenation catalyst in the presence of ammonia and hydrogen and in the presence or absence of an organic solvent at a temperature of from 20 to 150 C. and a pressure of from 0.3 to 50 MPa.

10. The process according claim 1, wherein a catalyst is used for the hydrogenation selected from the group consisting of nickel, copper, iron, palladium, rhodium, ruthenium and cobalt catalysts.

11. The process according to claim 10, wherein the hydrogenation catalyst is selected from the group consisting of Raney-type and supported catalysts.

12. The process according to claim 11, wherein the catalyst after activation has a composition in its entirety, in percent by weight based on all proportions of metals present, of cobalt: from 55 to 95 wt % aluminium: from 5 to 45 wt % chromium: from 0 to 3 wt % nickel: from 0 to 7 wt %

13. The process according to claim 1, wherein the cross-sectional loading is from 0.05 to 3.0 kg/m.sup.2*s.

14. The process according to claim 1, wherein the cross-sectional loading is from 0.05 to 2.0 kg/m.sup.2*s.

15. The process according to claim 3, wherein isophoronenitrile is subjected directly in one stage to aminating hydrogenation to give isophoronediamine in the presence of ammonia, hydrogen, a catalyst and possibly further additions.

16. The process according to claim 3, wherein isophoronenitrile is reacted in at least two stages, wherein said isophoronenitrile is initially converted in a first stage entirely or partly to isophoronenitrile imine which, as a pure substance or in a mixture with other components and unreacted isophoronenitrile, is hydrogenated in at least one subsequent stage to give isophoronediamine in the presence of at least ammonia, hydrogen and a catalyst.

17. The process according to claim 15, wherein the cross-sectional loading is from 0.01 to 4.0 kg/m.sup.2*s.

18. The process according claim 15, wherein the ratio of circulation stream to the feedstock stream supplied is in the range from 0:1 to 0.49:1.

19. The process according claim 15, wherein the hydrogenation is carried out at temperatures between 20 and 150 C. and pressures of from 0.3 to 50 MPa.

20. The process according to claim 16, wherein the cross-sectional loading is from 0.01 to 4.0 kg/m.sup.2*s.

Description

EXAMPLES

Production of the Catalyst, Cobalt Granules:

[0066] a) Production of the Alloy

[0067] The alloy is produced in an induction oven. This involves melting the metals in the appropriate amounts at 1500 C. The finished melt is cast to bars for further processing.

[0068] b) Production of the Granules

[0069] The alloy bars are precomminuted by means of a jaw crusher and ground further by means of a roll mill. A sieving step gives the desired size distribution of the granules through the choice of the appropriate sieves.

[0070] c) Activation of the Catalyst

[0071] The catalyst can be activated in a standard glass laboratory apparatus, for example in a glass beaker. An aqueous lye (e.g. sodium hydroxide solution) was added to the granules with stirring. The granules are in a catalyst basket during the activation. An exothermic operation leaches a portion of the aluminium out of the alloy with formation of hydrogen and sodium aluminate solution. The employed lye had a concentration of 20 wt % and the reaction temperature was 90 C. The degree of activation was determined via the reaction time. After activation, the catalyst is washed with water and then stored under water.

[0072] After activation the employed catalyst in its entirety has the following composition in weight percent (wt %), wherein the proportions add up to 100 wt %, based on the metals present:

cobalt: 55% by weight
aluminium: 42% by weight
chromium: 1% by weight
nickel: 2% by weight

[0073] A sieve fraction was used with particle sizes of the catalyst, i.e. the granule particles, having a statistical distribution between 2.0 and 5.0 millimetres (mm), where up to 10 percent of the particles may also be outside said range of said lower limit or upper limit, but up to 10 percent in each case may also be outside said range of said lower limit and upper limit.

Preparation of IPDA

[0074] Catalysts are tested for their catalytic activity in the preparation of 3-aminomethyl-3,5,5-trimethylcyclohexylamine (isophoronediamine, IPDA) from 3-cyano-3,5,5-trimethylcyclohexanone (isophoronenitrile, IPN) in a two-stage process.

[0075] In the first reaction stage, isophoronenitrile was at least partly converted to 3-cyano-3,5,5-trimethylcyclohexane imine with ammonia in the presence of an imination catalyst at 45 C. and, in the second reaction stage, subjected to aminating hydrogenation with hydrogen in the presence of ammonia over a hydrogenation catalyst at a temperature of 100 C. and a pressure of 250 bar. Each stage of the preparation was conducted in a separate reactor with individual temperature control. Both reactors, however, were connected in series in this case.

[0076] The hydrogenation reactor used has an internal diameter of 2 cm and was filled with 37 ml of the catalyst to be tested. The input solution of IPN (14.6 wt %) and ammonia (85.4 wt %) was pumped through the reaction tube from the top downwards at a volume flow rate of 108 ml/h, which corresponds to a cross-sectional loading of 0.06 kg/m.sup.2*s. The hydrogen was added separately, likewise from the top, at a volume flow rate of 40 NI/h. The product solution was collected beneath the reactor in a separating vessel and the composition thereof investigated by gas chromatography. The result is reported in Table 1.

TABLE-US-00001 TABLE 1 Temperature Cross-sectional loading IPDA yield/GC % Conversion 100 C. 0.06 kg/m.sup.2 * s 96.9% 99.9%

Preparation of TMD

[0077] Catalysts for the preparation of trimethylhexamethylenediamine (TMD) from trimethylhexamethylenedinitrile (TMN) are tested for their catalytic activity in a single-stage continuous process.

[0078] In the reaction, TMN was hydrogenated with hydrogen over a hydrogenation catalyst (cobalt granules) at a temperature of 80 C. and a pressure of 250 bar in the presence of ammonia as solvent.

[0079] The hydrogenation reactor used has an internal diameter of 2 cm and was filled with 42 ml of the catalyst to be tested. The input solution of TMN (14.6 wt %) and ammonia (85.4 wt %) was pumped through the reaction tube from the top downwards at a volume flow rate of 120 ml/h, which corresponds to a cross-sectional loading of 0.08 kg/m.sup.2*s. The hydrogen was added separately, likewise from the top, at a volume flow rate of 40 NI/h. The product solution was collected beneath the reactor in a separating vessel and the composition thereof investigated by gas chromatography. The result is reported in Table 2.

TABLE-US-00002 TABLE 2 Yield Temperature Cross-sectional loading of TMD/GC % Conversion 80 C. 0.08 kg/m.sup.2 * s 91.3% 99.9%