KR100432547B1 - Process for hemihydrogenation of dinitriles to aminonitriles - Google Patents

Abstract

The present invention relates to reactive hydrogenation of dinitriles to the corresponding aminonitriles.

More specifically, the present invention is selected from elements of the Groups IVb, VIb, VIIb and VIII of the Periodic Table as published by Raney Nickel, Raney Cobalt, Handbook of Chemistry and Physics (Weast, 5th edition, 1970-1971). Raney nickel containing doping elements and zinc, and catalysts selected from doping elements and zinc containing Raney cobalt containing doping elements selected from elements of Groups IVb, VIb, VIIb and VIII of the Periodic Table of the Elements, and strong inorganics derived from alkali or alkaline-earth metals In the presence of a base, with the help of hydrogen, the aliphatic dinitrile is semihydrogenated with the corresponding aminonitrile:

The initial hydrogenation mixture is at least 0.5% by weight relative to the total amount of liquid compounds in the mixture, diamines and / or aminonitriles that can be formed from dinitrile to be hydrogenated, and 80% for the combined amount of these three compounds Containing from 99.5% to unconverted dinitrile,

And a process characterized in that at least 60% selectivity can be obtained with respect to the desired aminonitrile and the degree of conversion of the dinitrile can reach 95%.

Description

Method for Hemihydrogenation of Dinitrile to Aminonitrile {PROCESS FOR HEMIHYDROGENATION OF DINITRILES TO AMINONITRILES}

The present invention relates to hemihydrogenation of dinitriles to the corresponding aminonitriles.

Hydrogenation of dinitrile is generally carried out to prepare the corresponding diamines; Thus, in particular, the hydrogenation of adiponitrile produces hexamethylenediamine, which is itself one of two base compounds for the production of polyamide 6.6.

However, it may sometimes be found necessary to prepare intermediate aminonitriles but not diamines. Although this does not imply any limitation, it is for example aminocapronitrile, which is a compound that can be converted, for example, of adiponitrile, subsequently to caprolactam, a base compound for polyamide 6, or directly to polyamide 6 This is the case of semihydrogenation of the furnace.

Thus, U.S. Patent No. 4 389 348 discloses a process for hydrogenating dinitrile to omega-aminonitrile using hydrogen in ammonia and an aprotic solvent medium in the presence of rhodium deposited on the underlying support.

US Pat. No. 5,151,543 discloses at least 2/1 mole of dinitrile, including alkanols containing inorganic bases soluble in liquid ammonia or alkanols in the presence of Raney nickel or cobalt type catalysts. A method of partially hydrogenating dinitrile with omega-aminonitrile in an excess of solvent is disclosed.

WO-A-93 / 16034 discloses 6-aminocapronitrile by hydrogenating adiponitrile under pressure at a temperature of from 50 to 90 ° C. in the presence of alkali metal hydroxides or ammonium hydroxide, low cost transition metal complexes and Raney nickel catalysts. Disclosed is a manufacturing method of. This method is carried out in accordance with an embodiment in a solvent such as lower alkanol or hydrocarbon.

The present invention relates to the preferential hydrogenation of a single nitrile functional group of dinitrile (hereafter referred to as hemihydrogenation) in order to produce diamine only as the corresponding aminonitrile and secondary product as the main product.

More specifically, the present invention is based on elements of the Periodic Tables IVb, VIb, VIIb, and VIII of the Periodic Table of the Elements as published by Raney Nickel, Raney Cobalt, Handbook of Chemistry and Physics (Weast, 5th edition, 1970-1971). Raney Nickel containing doping element and zinc selected, and Doping element selected from elements of group IVb, VIb, VIIb and VIII of the Periodic Table of the Elements and catalyst selected from Raney cobalt containing zinc and alkali or alkaline-earth metals In the presence of a strong inorganic base, with the aid of hydrogen, the aliphatic dinitrile is semihydrogenated with the corresponding aminonitrile:

The initial hydrogenation mixture comprises at least 0.5% by weight of water relative to the total amount of liquid compounds in the mixture, diamines and / or aminonitriles that can be formed from dinitrile to be hydrogenated, and the total combined amount of these three compounds in the mixture Containing unconverted dinitrile in a proportion of 80% to 99.5% relative to the total amount of the liquid compound,

-The degree of conversion of dinitrile can reach 95%,

And a method in which the desired aminonitrile can be obtained with a selectivity of at least 60% by the above method.

The degree of conversion of dinitrile is preferably 70% or more.

The dinitriles that can be used in the process of the invention are more particularly dinitriles of the formula (I):

   NC-R-CN (I) wherein R represents straight or branched chain alkylene or alkenylene containing 1 to 12 carbon atoms.

In the process of the invention it is preferred to use dinitriles of the formula (I) in which R represents a straight or branched chain alkylene radical containing 1 to 6 carbon atoms.

Examples of such dinitriles that may be mentioned are in particular from the same method as the synthesis of adiponitrile, methylglutaronitrile, ethylsuccinonitrile, malononitrile, succinonitrile and glutaronitrile and mixtures thereof, in particular adipotitryl Adiponitrile and / or methylglutaronitrile and / or ethylsuccinonitrile which may be produced.

Indeed, the case where R = (CH ₂ ) ₄ is the most common case, since this case corresponds to the use of adipononitrile (ADN) in the process.

Strong inorganic bases generally consist of alkali or alkaline-earth metal hydroxides, carbonates and alkanolates. Preference is given to being selected from alkali metal hydroxides, carbonates and alkanolates.

In the matter of priority, the strong inorganic base used is selected from the following compounds: LiOH, NaOH, KOH, RbOH, CsOH and mixtures thereof.

Although RbOH and CsOH show very good results, in practice NaOH and KOH are most commonly used as good performance-price compromises.

The reaction mixture has various compositions depending on the type of run of the process.

Indeed, when the process is carried out discontinuously, particularly in the case of laboratory implementation or small intermittent production, the aminonitrile gradually increases in the initial reaction mixture and the diamine increases in smaller proportions, whereas The edinitrile concentration can be reduced if most of the dinitrile is charged at the beginning of hemihydrogenation, or can remain relatively constant if dinitrile is gradually introduced during the reaction.

On the other hand, when the process is carried out continuously, the average composition of the reaction mixture leads to a value determined by the selectivity of the reaction.

Water is generally present in amounts up to 20%. The water content of the reaction mixture is preferably 2% to 15% by weight relative to the total combined amount of the liquid components in the mixture.

The concentration of the desired aminonitrile and / or the corresponding diamine and unconverted dinitrile in the reaction mixture is generally from 85% to 98% by weight relative to the combined total amount of the liquid contained in the reaction mixture.

In the continuous operation of the process of the invention, the average concentration will be determined by the ratio of the selectivity to the respective selectivity to aminonitrile and diamine and the rate of introduction of dinitrile.

The amount of strong inorganic base is advantageously at least 0.1 mol per kg catalyst. It is preferable that it is 0.1 mol-3 mol per kg catalyst, and it is more preferable that it is 0.2 mol-2 mol per kg catalyst.

In order to obtain optimal selectivity to aminonitrile, the strong inorganic base / catalyst ratio can be modified depending on the base used. Thus, for KOH, RbOH and CsOH, it will be more preferred that the ratio is 0.2 to 1.0 mole per kg catalyst, especially Raney nickel, whether doped or not. For NaOH and LiOH, it will be more preferred that the ratio is 0.2 to 1.5 moles per kg of catalyst, in particular Raney nickel, whether doped or not.

The catalyst used in the process is in addition to Raney nickel, Raney cobalt, nickel or cobalt, in addition to the metal removed from the original alloy during the preparation of the catalyst, i.e. generally aluminum residual, for example chromium, titanium, molybdenum, tungsten, iron or Raney nickel or Raney cobalt containing one or more other elements, often called dopants, such as zinc. Of these doping elements, chromium, titanium and mixtures thereof with one another and mixtures thereof with iron are considered to be the most advantageous. Such dopants usually represent 0% to 10% by weight, preferably 0% to 5% by weight per nickel or cobalt weight.

If the catalyst contains a dopant such as chromium or titanium, it is also advantageous to consider the strong salt / dopant ratio. Therefore, it is preferable to use a KOH / dopant ratio of 12-30 moles per kg dopant and a NaOH / dopant ratio of 12-50 moles per kg dopant.

The amount of catalyst used can vary widely, particularly depending on the operating method adopted and the function of the reaction conditions chosen. Thus, when dinitrile is gradually introduced into the reaction mixture, the weight ratio of dinitrile to be catalyst / hydrogenated is much higher than if all dinitriles were used at the beginning of the reaction. To be indicated, from 0.5% to 50% by weight, in most cases from 1% to 35% by weight of the catalyst can be used relative to the total weight of the reaction mixture.

With the degree of conversion of a given catalyst and a given dinitrile, the yield of aminonitrile exceeds the peak determined by the base / Ni or base / Co ratio selected from the values in the ranges indicated above.

At a constant degree of dinitrile conversion, the optimum yield of aminonitrile also depends on the nature and content of the dopant, the amount of water in the reaction mixture and the temperature.

Overall selectivity to aminonitrile is improved by increasing the value of dinitrile to aminonitrile, and not reduced by decreasing value of aminonitrile to diamine. Affected by the various parameters indicated above is essentially the rate constant of the first of two successive reactions.

The process of the invention is generally carried out at reaction temperatures of up to 150 ° C., preferably up to 120 ° C., more preferably up to 100 ° C.

Specifically, the temperature is from ambient temperature (about 20 ° C) to 100 ° C.

Before heating, simultaneously with heating or after heating, the reactor is subjected to a suitable hydrogen pressure, ie in practice from 1 bar (0.10 MPa) to 100 bar (10 MPa), preferably from 5 bar (0.5 MPa) to 50 bar (5 MPa). Hydrogen pressure).

The reaction period may vary depending on the reaction conditions and the catalyst.

In non-continuous operation it can vary from several minutes to several hours.

In continuous operation, which is the preferred industrial method of the process according to the invention, it is clear that the duration is not a major factor.

It should be noted that, depending on the working conditions, one skilled in the art can modify the order of the steps of the method according to the invention.

 Other conditions for controlling other hydrogenation (using a continuous or discontinuous process) in the present invention are conventional and fall within the technical scope known per se.

The following examples illustrate the invention.

In the examples the following abbreviations may be used:

ADN = adiponitrile

ACN = aminocapronitrile

HMD = hexamethylenediamine

DC = degree of conversion

CY = selectivity based on the converted initial substrate (in this case based on ADN).

Example 1

The following is charged into a 300-ml stainless steel reactor equipped with a Rushton cavitation type stirrer, a means for introducing reactants and hydrogen, and a temperature control system:

Adiponitrile 95.1 g

Hexamethylenediamine 94.2 g

21.1 g of water

-KOH 0.056 g

Raney Ni (containing 1.7% Cr) 2.5 g Ni

In this example, 0.4 mol KOH per kg of Raney Ni.

After purifying the reactor with nitrogen and then hydrogen, the reaction mixture is heated to 50 ° C. and then the pressure is adjusted to 2 MPa by continuously adding hydrogen at this temperature. After the progress of the reaction hydrogen is consumed and analyzed by vapor phase chromatography (GC) of the reaction mixture sample. When the optimum yield is reached, the reaction is stopped by stopping the stirring and cooling the reaction mixture.

The following results are obtained:

-80 minutes reaction time

-DC 83.5% of ADN

-CY 77.5% of ACN

Example 2

Example 1 is repeated with the same operating conditions and the following packing:

Adiponitrile 95.1 g

Hexamethylenediamine 95.4 g

21.1 g of water

-KOH 0.113 g

Raney Ni (containing 1.7% Cr) 2.5 g Ni

In this example it is 0.8 mol KOH per kg of Raney Ni.

The following results are obtained:

-80 minutes reaction time

-DC 81.9% on ADN

-CY 68.3% in ACN

Example 3

Example 1 is repeated with the same operating conditions and the following packing:

Adiponitrile 27.4 g

166.4 g of hexamethylenediamine

19.4 g of water

-KOH 0.115 g

Raney Ni (containing 1.7% Cr) 2.5 g Ni

In this example it is 0.8 mol KOH per kg of Raney Ni.

The following results are obtained:

-Reaction time 20 minutes

DC 71.2% of ADN

-CY 77.0% of ACN

Example 4

Example 1 is repeated with the same operating conditions and the following packing:

Adiponitrile 142.4 g

47.75 g of hexamethylenediamine

21.1 g of water

-KOH 0.053 g

Raney Ni (containing 1.7% Cr) 2.5 g Ni

In this example, 0.4 mol KOH per kg of Raney Ni.

The following results are obtained:

-Reaction time 103 minutes

-DC 76.2% of ADN

-CY 77.2% of ACN

Example 5

Example 1 is repeated with the same operating conditions and the following packing:

Adiponitrile 95.1 g

97.1 g of hexamethylenediamine

21.1 g of water

-KOH 0.056 g

Raney Ni (containing 2.4% Cr and 1.3% Fe) 2.5 g Ni

In this example, Raney is 0.4 mol KOH / kg Ni and 16.7 mol KOH / kg Cr.

The following results are obtained:

-Reaction time 45 minutes

-DC 82.4% of ADN

-CY 74.3% of ACN

Example 6

Example 1 is repeated with the same operating conditions and the following packing:

Adiponitrile 95.0 g

Hexamethylenediamine 97.3 g

21.1 g of water

-KOH 0.056 g

Raney Ni (containing 3.0% Cr and 1.6% Fe) 2.5 g Ni

In this example, Raney is 0.4 mol KOH / kg Ni and 13.3 mol KOH / kg Cr.

The following results are obtained:

-Reaction time: 85 minutes

-DC 84.5% of ADN

-CY 65.9% of ACN

Example 7

The following is charged into a 150-ml stainless steel reactor equipped with a magnetic stirrer, reactants and means for introducing hydrogen and a temperature control system:

Adiponitrile 21.65 g

21.65 g of hexamethylenediamine

-4.75 g of water

-KOH 0.0372 g

-Raney Ni (containing 1.7% Cr) 0.58 g Ni

In this example, 1.6 mol NaOH per kg of Raney Ni.

After purifying the reactor with nitrogen and then hydrogen, the reaction mixture is heated to 50 ° C. and then the pressure is adjusted to 2 MPa by continuously adding hydrogen at this temperature. After the progress of the reaction, hydrogen is consumed and analyzed by vapor phase chromatography (GC) of the reaction mixture sample. When the optimum yield is reached, the reaction is stopped by stopping the stirring and cooling the reaction mixture.

The following results were obtained:

-90 minutes reaction time

-DC 70% of ADN

-62% CY of ACN

Example 8

Example 7 is repeated with the same operating conditions and the following packing:

Adiponitrile 21.6 g

21.8 g of hexamethylenediamine

-4.75 g of water

NaOH 0.0046 g

Raney Ni (containing 1.7% Cr) 0.58 g Ni

In this example, 0.2 mol NaOH per kg of Raney Ni.

The following results are obtained:

-Reaction time 107 minutes

-DC 76% of ADN

-62% CY of ACN

Example 9

Example 7 is repeated with the same operating conditions and the following packing:

Adiponitrile 21.6 g

21.7 g of hexamethylenediamine

-4.78 g of water

NaOH 0.0094 g

Raney Ni (containing 1.7% Cr) 0.58 g Ni

In this example, 0.4 mol NaOH per kg of Raney Ni.

The following results are obtained:

-Reaction time 67 minutes

DC 80% of ADN

-69% of CY in ACN

Example 10

Example 7 is repeated with the same operating conditions and the following packing:

Adiponitrile 21.6 g

21.6 g of hexamethylenediamine

-4.75 g of water

0.0187 g of NaOH

Raney Ni (containing 1.7% Cr) 0.58 g Ni

In this example, 0.8 mol NaOH per kg of Raney Ni.

The following results are obtained:

69 min reaction time

DC 75% of ADN

-73% of ACN CY

Example 11

Example 7 is repeated with the same operating conditions and the following packing:

Adiponitrile 21.65 g

21.65 g of hexamethylenediamine

-4.75 g of water

NaOH 0.026 g

Raney Ni (containing 3.6% Cr) 0.58 g Ni

In this example, 0.8 mol NaOH per kg of Raney Ni.

The following results are obtained:

-Reaction time: 51 minutes

DC 75% of ADN

-67% of CY in ACN

Example 12

The following is charged into a metal reactor equipped with cavitation-type agitators, reactants and means for introducing hydrogen and other control systems:

Adiponitrile 2856 kg

1151 kg hexamethylenediamine

-588 kg of water

-KOH 0.83 kg

-Raney Ni (containing 1.7% Cr) 37 kg

The reaction is carried out at the operating conditions described in Example 1.

The following results are obtained:

-Reaction time: 3 hours 30 minutes

-DC 86% of ADN

-64% of CY in ACN

Example 13

The following is charged into a 150-ml stainless steel reactor equipped with a magnetic stirrer, reactants and means for introducing hydrogen and a temperature control system:

Adiponitrile 6 g

41.16 g of hexamethylenediamine

0.84 g of water

0.054 g of CsOH

Raney Ni (containing 12% Fe) 0.4 g

In this example, 0.9 mol CsOH per kg of Raney Ni.

After purifying the reactor with nitrogen and then hydrogen, the reaction mixture is heated to 80 ° C. and then the pressure is adjusted to 2.5 MPa by continuously adding hydrogen at this temperature. After the progress of the reaction hydrogen is consumed and analyzed by vapor phase chromatography (GC) of the reaction mixture sample. When the optimum yield is reached, the reaction is stopped by stopping the stirring and cooling the reaction mixture.

The following results are obtained:

50 minutes reaction time

-ADN DC 89%

-65% of CY in ACN

Example 14

Example 13 is repeated with the same operating conditions and the following packing:

Adiponitrile 6 g

37.8 g of hexamethylenediamine

-4.2 g of water

0.036 g NaOH

Raney Ni (containing 1.5% Ti) 0.4 g

In this example, 0.6 mol CsOH per kg of Raney Ni.

The following results are obtained:

-Reaction time 20 minutes

-DC 90% of ADN

-60% CY of ACN

Claims (19)

Raney nickel, Raney cobalt, doping elements selected from elements of the Periodic Tables IVb, VIb, VIIb and VIII and Raney Nickel containing zinc and doping elements selected from the elements of Groups IVb, VIb, VIIb and VIII of the Periodic Table and In the presence of a catalyst selected from Raney cobalt containing zinc and a strong inorganic base derived from an alkali or alkaline earth metal, with the aid of hydrogen, the dinitrile of formula (I) is semihydrogenated with the corresponding aminonitrile, The initial hydrogenation mixture is water in a proportion of at least 0.5% and at most 20% by weight relative to the total amount of liquid compounds in the mixture, diamines, aminonitriles, or diamines and aminonitriles, which may be formed from dinitriles to be hydrogenated, and these three Contains from 80% to 99.5% of unconverted dinitrile relative to the total amount of liquid compound in the mixture for the combined amount of compound, The degree of conversion of dinitrile can range from 70% to 95%, And a process characterized in that the desired aminonitrile can be obtained with a selectivity of at least 60% by this method: [Formula I] NC-R-CN (I) wherein R represents straight or branched chain alkylene or alkenylene containing 1 to 12 carbon atoms. The method of claim 1 wherein the inorganic base is selected from alkali metal or alkaline-earth metal hydroxides, carbonates and alkanolates. The process according to claim 1, wherein the strong inorganic base used is selected from the following compounds: LiOH, NaOH, KOH, RbOH, CsOH and mixtures thereof. The process of claim 1, wherein the amount of inorganic base present in the reaction mixture is between 0.1 and 3 moles per kg catalyst. The process according to claim 1, wherein the amount of KOH, RbOH or CsOH inorganic base present in the reaction mixture is 0.2 to 1.0 mole per kg catalyst, whether doped or not. The process according to claim 1, wherein the amount of NaOH or LiOH inorganic base present in the reaction mixture is 0.2 to 1.5 moles per kg catalyst, whether doped or not. The method of claim 1 wherein the water is present in the reaction mixture in an amount of from 2% to 15% by weight relative to the combined total amount of the liquid components of the mixture. The method of claim 1, wherein the concentration of the desired aminonitrile, the corresponding diamine, or the desired aminonitrile and the corresponding diamine, and the unconverted dinitrile in the reaction mixture is from 85% by weight to the total combined amount of the liquid contained in the reaction mixture. 98 weight percent. 2. The catalyst of claim 1 wherein the catalyst used is selected from Raney nickel, Raney cobalt, and Raney nickel or Raney cobalt containing one or more other doping elements such as chromium, titanium, molybdenum, tungsten, iron or zinc. Way. The process according to claim 1, wherein the catalyst used is selected from Raney nickel containing at least one doping element selected from chromium, titanium and mixtures thereof with one another and mixtures with iron thereof. The process according to claim 1, wherein the catalyst used is selected from Raney nickel containing 0 to 10% by weight of one or more doping elements per weight of nickel. The catalyst of claim 1, wherein the catalyst contains a dopant selected from chromium or titanium, wherein a KOH / dopant ratio of 12-30 moles per kg dopant and a NaOH / dopant ratio of 12-50 moles per kg dopant are used. Characterized in that the method. The process according to claim 1, wherein the catalyst used represents 0.5% to 50% by weight relative to the total weight of the reaction mixture. The process according to claim 1, which is carried out at a reaction temperature of 150 ° C or less. The process according to claim 1, wherein the operation is carried out at hydrogen pressure between 1 bar (0.10 MPa) and 100 bar (10 MPa). 6. The process of claim 5 wherein the catalyst is Raney nickel. 7. The process of claim 6 wherein the catalyst is Raney nickel. The process according to claim 1, wherein R represents a straight or branched chain alkylene radical containing 1 to 6 carbon atoms. 12. The method of claim 11, wherein Raney nickel contains 0 to 5 weight percent of one or more doping elements per weight of nickel.