Method for the preparation of aminonitriles and diamines

Abstract

The present invention relates to an improvement in a process for the simultaneous production of aminonitriles and diamines by the hydrogenation of dinitriles. The improvement in the hydrogenation process is that a hydrogenation catalyst such as at least one nickel or cobalt catalyst modified ex situ with preadsorbed alkali metal phosphates and / or pyrophosphates such as M3PO4 and M4P2O7 (M = K, Rb or Cs), or mixtures thereof is used.

Description

[0001] P141311-1998P-LG

[0002] METHOD FOR THE PREPARATION OF AMINONITRILES AND DIAMINES

[0003] FIELD OF THE INVENTION

[0004] The present invention relates to a process for producing aminonitriles and diamines by the catalytic hydrogenation of dinitriles. In particular, the invention relates to a process for producing simultaneously aminonitriles and diamines, in which, a modified nickel or cobalt catalyst is applied. Furthermore, the invention relates to a modified nickel or cobalt catalyst, which is obtained by adsorption of alkali metal phosphates and / or pyrophosphates on a nickel or cobalt catalyst.

[0005] BACKGROUND OF THE INVENTION

[0006] Catalytic processes for the hydrogenation of dinitriles to produce diamines and / or aminonitriles are known. Representative patents illustrating the hydrogenation of dinitriles to produce diamines and / or aminonitriles are as follows:

[0007] U.S. Pat. Nos. 2,208,598 and 2,257,814 each to Dupont, and German Pat. Nos. 836,938 and 848,654 and 954,416 all to BASF, disclose various catalytic processes directed to producing omega-aminonitriles from dinitriles employing miscellaneous catalysts including Raney nickel and iron.

[0008] U.S. Pat. No. 3,972,938 discloses a process for the production of hexamethylenediamine by the catalytic hydrogenation of adiponitrile in the presence of ammonia using cobalt, manganese and phosphoric acid containing catalyst.

[0009] U.S. Pat. No. 4,389,348 discloses that rhodium-based catalysts selectively hydrogenate dinitriles to aminonitriles in the presence of an aprotic solvent for the dinitrile and ammonia. However, in Example 10 of the U.S. Patent, increased amounts of ammonia even in the presence of aprotic solvent, such as THF, completely prevented rhodium catalyzed hydrogenation of the dinitrile.

[0010] U.S. Pat. No. 4,601,859 discloses a process for the production of omega- aminonitrile by the catalytic hydrogenation of dinitriles using a supported highly dispersed rhodium catalyst in the presence of high concentrations of ammonia.

[0011] U.S. Pat. No. 5,151,543 discloses a process for the selective hydrogenation of aliphatic dinitriles to aminonitriles at low temperature and pressure in the presence of a Raney nickel or Raney cobalt catalyst and liquid ammonia or an alcohol solvent containing an inorganic base. U.S. Pat. No. 5,296,628 and WO 93 / 16034 discloses a process for the conversion of adiponitrile to 6-aminocapronitrile in high yield and high selectivity using Raney nickel catalyst and a reaction mixture containing an alcohol solvent, alkali metal hydroxide and a low valent transition metal complex.

[0012] U.S. Pat. No. 5,512,697 discloses a process for preparing aliphatic alpha, omega- aminonitriles by partial hydrogenation of aliphatic alpha, omega-dinitriles at elevated temperatures and superatmospheric pressure in the presence of a base and of a Raney nickel catalyst, by carrying out the hydrogenation in the presence of ammonia and lithium hydroxide or of a compound which gives lithium hydroxide during the hydrogenation.

[0013] U.S. Pat. No. 5,574,181 discloses a process for the preparation of an aminonitrile by partially hydrogenating a nitrile compound with two or more nitrile groups in the presence of a Raney nickel catalyst, the hydrogenation being carried out under water- free reaction conditions and the catalyst having been treated with an alkali metal alkanolate or an earth alkali metal alkanolate such as sodium or potassium methanolate.

[0014] U.S. Pat. No. 5,717,090 and WO 96 / 20931 discloses a process for the simultaneous preparation of caprolactam and hexamethylenediamine from adiponitrile over Raney nickel catalyst in the presence of ammonia. The resulting 6- aminocapronitrile is cyclized to form caprolactam.

[0015] U.S. Pat. Nos. 5,827,938 and 5,874,607 and 6,080,883 discloses a process for the coproduction of 6-aminocapronitrile and hexamethylenediamine by treatment of adiponitrile with hydrogen in the presence of a nickel-containing catalyst at temperatures not below room temperature and elevated hydrogen partial pressure in the presence or absence of an ammonia solvent.

[0016] U.S. Pat. No. 5,900,511 discloses a process for continuous hydrogenation of adiponitrile to hexamethylenediamine and optionally to amninocapronitrile at relatively low temperature and pressure using a sponge cobalt catalyst in a reaction medium that is substantially free of caustic.

[0017] U.S. Pat. No. 5,981,790 and WO 96 / 18603 discloses the hydrogenation of an aliphatic dinitrile to an aminonitrile (e.g., of adiponitrile to aminocapronitrile) with hydrogen in the presence of Raney nickel or Raney cobalt doped with a Group IVB, VIB, VIIB or VIII element compound or Zn and a strong inorganic base derived from an alkali or alkali earth metal, the reaction medium being water. U.S. Pat. No. 5,986,127 discloses a process for producing an aminonitrile comprising contacting a dinitrile with a hydrogen-containing fluid in the presence of a solvent comprising liquid ammonia or an alcohol, at least one metal catalyst, and a carbonyl group-containing additive such as, for example, organic amides, organic esters, salts of carboxylic acids or urea.

[0018] U.S. Pat. No. 6,080,884 discloses a process for producing an aminonitrile from a dinitrile comprising contacting a dinitrile with a hydrogen-containing fluid in the presence of a solvent and a metal catalyst in which the solvent comprises liquid ammonia, an alcohol, ammonium hydroxide, or combinations thereof and the metal catalyst comprises nickel and iron and can be supported on an inorganic support such as, for example, magnesium oxide.

[0019] U.S. Pat. No. 6,232,488 discloses a process for the continuous hydrogenation of dinitrile to produce at least one corresponding aminonitrile, in the presence of a Raney nickel catalyst and an alkaline metal hydroxide.

[0020] U.S. Pat. No. 6,258,745, U.S. Pat. No. 6,455,723, U.S. Pat. No. 6,455,724, U.S. Pat. No. 6,506,927, U.S. Pat. No. 6,566,297, U.S. Pat. No. 6,569,802, U.S. Pat. No. 6,680,403, U.S. Pat. No. 6,710,201, U.S. Pat. No. 6,720,444, U.S. Pat. No. 6,737,540 and U.S. Pat. No. 6,841,507 discloses a process for producing aminonitriles by contacting the corresponding dinitriles with a hydrogen-containing fluid in the presence of a hydrogenation catalyst (such as Raney nickel, Raney cobalt, Sponge nickel or Rh / AhCh), a solvent comprising an alcohol or liquid ammonia, and an additive for improving the yield of and / or selectivity to the aminonitrile. The additive comprises a carbon monoxide; a tetraalkylammonium hydroxide compound; a tetraalkylphosphonium hydroxide compound; a multi -centered metal carbonyl cluster; an organic isonitrile; a cyanide compound; a quaternary ammonium cyanate compound; a divalent sulfur and selenium compounds; an azide compound; an amide compound; and a fluoride compound.

[0021] U.S. Pat. No. 6,376,714 discloses a process for converting dinitriles to diamines and / or aminonitriles, comprising contacting a Group VIII element-containing hydrogenation catalyst (such as Raney nickel or Ru-promoted Co / AhOs) with a modifier selected from the group of compounds consisting of quaternary ammonium hydroxides, quaternary ammonium cyanides, quaternary ammonium fluorides, quaternary phosphonium hydroxides, and quaternary ammonium thiocyanides to form a modified catalyst; in the absence of the ammonia solvent.

[0022] U.S. Pat. No. 6,384,283 discloses a process for the preparation of aminonitrile and of diamine by catalytic hydrogenation of aliphatic dinitrile having from 3 to 12 carbon atoms, in the presence of a Raney nickel catalyst and an alkaline metal hydroxide, separating the catalyst from the reaction mixture, acidifying the reaction mixture by addition of a sufficient amount of an inorganic or organic acid, and extracting, by distillation, the products of the reaction and the unconverted dinitrile.

[0023] U.S. Pat. No. 6,521,779 discloses a process for the hemihydrogenation of a dinitrile into the corresponding aminonitrile, in a liquid medium, characterized in that it consists in operating in the presence of a Raney nickel or cobalt catalyst containing copper and / or silver and / or gold and in the presence of an alkaline or alkaline earth metal hydroxide.

[0024] U.S. Pat. No. 6,790,994 discloses a process for the hydrogenation of nitrile functional groups to amine functional groups using hydrogen in the presence of a hydrogenation catalyst (such as Raney nickel or supported ruthenium) and a strong inorganic base derived from an alkali metal or alkaline earth metal, and amine solvent compound, such as hexamethylenedi amine.

[0025] IT Pat. No. 845,999 discloses the partial hydrogenation of dinitriles having one or two carbons shorter than adiponitrile (e.g., succinonitrile) in the presence of a rhodium catalyst and ammonia to produce an omega-aminonitrile.

[0026] WO 98 / 43940 discloses a process for continuous hydrogenation of adiponitrile to hexamethylenediamine and optionally to aminocapronitrile involving the catalytic hydrogenation of adiponitrile at relatively low temperature and pressure using a Raney cobalt catalyst.

[0027] WO 2000 / 027525 and 2000 / 027526 disclose a catalytic process for the coproduction of 6-aminocapronitrile and hexamethylenediamine by treatment of adiponitrile with hydrogen. The catalysts comprise iron, cobalt, and a third metal selected from the group consisting of nickel, rhodium, ruthenium, palladium, platinum, osmium, iridium and mixtures of any of these metals.

[0028] An article, Homogeneous and Heterogeneous Hydrogenation of Nitriles in a Liquid Phase: Chemical, Mechanistic, and Catalytic Aspects, Claude De Bellefon and Pierre Fouilloux; Catal. Rev.-Sci. Eng., vol. 36(3), pp. 459-506, 1994 discloses the semihydrogenation of dinitriles using a variety of catalysts, e.g., doped or undoped rhodium, palladium, iron, nickel, cobalt, Raney nickel and Raney cobalt.

[0029] Alkali metal phosphates were also used for promoting the selectivity of rhodium and palladium catalysts for the preparation of amines. JP Pat. No. 59,216,852 discloses the preparation of alicyclic diamines by nucleus hydrogenation of aromatic diamines in aqueous media in the presence of RI1 / AI2O3 catalysts and NasPC , K3PO4, NH3, aliphatic secondary amines, or aliphatic tertiary amines.

[0030] We identified BASF's PCT patent application, WO 2007 / 031488, as the closest prior art (BASF application). It provides an efficient and controllable process for the hydrogenation of nitriles to primary amines or aminonitriles using a specially pretreated catalyst. It offers high selectivity and reduced amounts of by-products, and also eliminates the need for toxic substances and expensive materials, making it highly suitable for industrial applications in the production of key compounds for polyamide manufacturing and other chemical industries. The catalyst can be pure metals, alloys, sponges (such as Raney® nickel or cobalt), or supported on materials such as aluminum oxide, magnesium oxide, or silicon dioxide. According to the invention, the catalyst is treated with compound A to enhance activity and selectivity. Compound A includes carbonates, hydrogen carbonates, oxocarbonates, carboxylates, dihydrogen phosphates, hydrogen phosphates, phosphates, acetates, formates, oxalates of alkali metals, alkaline earth metals, or ammonium. Among these, only carbonates^. such as sodium carbonate, potassium carbonate, magnesium carbonate, are discussed in detail in the specification, while the other compounds are mentioned only in the above general list. Accordingly, our present invention - which concentrates on phosphate containing modifiers of usual Ni and Co based catalyst - is a co-called “selection invention” in the light of the BASF application. In the following, we shall compare our results with the results obtained by catalysts applied in the BASF application.

[0031] SUMMARY OF THE INVENTION

[0032] The objective of this invention is to suppress the formation of byproducts (e.g. bis-hexamethylenetriamine, hexamethyleneimine and diaminocyclohexane) during the hydrogenation of dinitriles to aminonitriles and diamines. This is achieved by the controlled modification of a Raney nickel hydrogenation catalyst. The ideal catalyst modifier is strongly basic, adheres well to the catalyst surface, and can form an ideal adherent layer structure. Additionally, in a preferred embodiment, this invention aims to omit ammonia or to keep its partial pressure as low as possible in the dinitrile hydrogenation process, making it a greener, more environmentally friendly technology.

[0033] In our research work we found that alkali metal phosphates, hydrogen phosphates and / or pyrophosphates, preferably alkali metal phosphates and / or pyrophosphates, where the alkali metal is selected from the group of K, Rb and Cs (where K is preferred), appeared to be the most effective modifiers for suppressing the formation of byproducts below 0.5w / w% in the hydrogenation of dinitriles, such as adiponitrile (i.e. the selectivity of the byproducts is low) while the selectivity of the desired products is exceptionally high. Due the use of the modified catalysts of the invention, the preferred selectivity results can be achieved even in the absence of ammonia. However, by the use of ammonia, the equilibrium of the dinitrile hydrogenation process may be shifted to the formation of the more valuable product, i.e. 6-aminocapronitrile (ACN). The low selectivity of the byproducts can be maintained with new alkali metal phosphates and / or pyrophosphates catalysts, while the adiponitrile conversion may reach practically 100%, independently from the fact whether ammonia was applied in the reaction system or not.

[0034] The modification of the hydrogenation catalyst may be carried out in a slurry using aqueous solution of the modifiers selected from alkali metal phosphates and / or alkali metal pyrophosphates, such as M3PO4 and M4P2O7 (M=K, Rb and Cs, where K is preferred), or mixtures thereof.

[0035] DETAILED DESCRIPTION OF THE INVENTION

[0036] The present invention is a process for the simultaneous production of aminonitriles and diamines - such as 6-aminocapronitrile (ACN) and hexamethylenediamine (HMD) - by the hydrogenation of dinitriles, such as adiponitrile (ADN). This process is carried out in a reaction mixture comprising (a) at least one dinitrile, (b) hydrogen, (c) at least one nickel or cobalt catalyst modified by an alkali metal phosphate, hydrogen phosphate and / or pyrophosphate, preferably alkali metal phosphate and / or pyrophosphate (such as M3PO4, M2HPO4 and M4P2O7, preferably M3PO4 and M4P2O7, where M = K, Rb and Cs, where K is preferred), or mixtures thereof, (d) optionally ammonia. The reaction conditions (pressure, temperature, reaction time) are in the ranges usually applied in hydrogenation. The modified catalyst is prepared ex situ, i.e., before the use in the above system.

[0037] The invention further provides a modified nickel or cobalt catalyst obtainable by adsorption of an above discussed alkali metal phosphate, hydrogen phosphate and / or pyrophosphate (herein also referred to as phosphate salts), preferably alkali metal phosphate and / or pyrophosphate on a nickel or cobalt catalyst. The non-modified (untreated) catalyst applied is known in the field, and particular preference is given to Raney nickel catalysts.

[0038] The non-modified (untreated) catalyst is preferably customary nickel or cobalt, Raney nickel (RNi) or Raney cobalt (RCo), where the nickel or RNi is more preferred, especially the RNi. The non-modified (untreated) catalyst is preferably available on the market, e.g. RNiB113W (Degussa) which was applied as RNi catalyst in most of the examples, but it can be changed for any other usual RNi (see examples 26, 30 and 32) or RCo catalyst (see example 29). The catalysts may be employed in their unpromoted and promoted forms. Promoters include for instance, Fe, Mo, Cr, V, Ti, and Zr, preferably Cr. However, the application of promoters is not important because the catalysts modified according to the invention are active enough without the use of promoter. The catalysts may be applied in their supported form. Support materials include, for example, SiCh, AI2O3, ZrCh, MgO, MnO, ZnO, CnCh and the like, preferably SiCh, AI2O3, MgO, MnO, most preferably AI2O3.

[0039] In the preparation process of the modified catalysts according to the invention the non-modified (untreated) catalyst is slurried in a solution, preferably in an aqueous solution of an above discussed alkali metal phosphate and / or pyrophosphate, and stirred under air or an inert gas, such as nitrogen, for a period of about 0.1-24 hours, preferably 0.5 to 12 hours, more preferably 0.7 to 1 hours.

[0040] The adsorption process is conducted in a solution comprising one or more above discussed alkali metal phosphate(s) and / or pyrophosphate(s), with concentrations of preferably from 10 g / l to 900 g / 1. It is preferable to employ aqueous solution for the adsorption process, with concentrations of 50 to 400 g / 1 being optimal.

[0041] The excess solution is separated after the adsorption by decantation or filtration or other type separation, optionally under an inert gas atmosphere, e.g. under nitrogen atmosphere. It is advantageous to wash the catalyst obtained after the adsorption with alcohol, preferably with EtOH, for removing the solvent applied in the adsorption. In a preferred embodiment, the modified catalyst is obtained from the slurry by decanting and subsequently washing the catalyst twice with ethanol or methanol in ambient atmosphere.

[0042] The applied alkali metal phosphates and / or pyrophosphates are present in the modified catalyst preferably in an amount of from about 1-20% by weight (m phosphate salts / m modified catalyst), preferably 3-18%, more preferably 5-16%, most preferably 6- 12% by weight.

[0043] The alkali metal content of the catalysts was determined by ICP and said values are presented in table 1 and in the examples. The m phosphate salts / m modified catalyst values are calculated from the alkali metal content measured by ICP.

[0044] The important parameters of the preparation process of the modified catalysts according to the invention are summarized in Table 1.

[0045] Table 1: Modification of the catalyst (conditions: mcataiyst= 6 g, T= room temperature, ambient atmosphere).

[0046] The process according to the invention is suitable for the hydrogenation of any dinitriles. The dinitriles are preferably of general formula NC-R-CN, in which R denotes a linear or branched alkylene or alkenylene group containing from 1-12 carbon atoms, preferably 3-6 carbon atoms, where the use of adiponitrile (where n=4) is especially preferred. The modified catalyst is typically present in the reaction mixture in an amount of from 1 to 50% by weight based on the dinitrile, preferably in an amount of from 2 to 30% by weight based on the dinitrile, and more preferably in an amount of from 4 to 15% by weight based on the dinitrile.

[0047] The hydrogenation process is carried in a usual way which is known for a skilled person, but by the use of a catalyst modified according to the invention.

[0048] The reaction mixture may also contain a solvent. For this purpose, it is preferably to use short-chain alcohols, especially methanol, ethanol and propanol, as well as hydrocarbons such as hexane, cyclohexane, and toluene. Hexamethylenediamine and / or water may also be used as a solvent. The solvent may be present in the mixture in amounts of from 0 to 90% by weight, based on the reaction mixture. However, in most cases it is advantageous to carry out the hydrogenation without solvent.

[0049] The reaction mixture may also contain alkali and alkaline earth metal inorganic bases such as Li, Na, K, Rb, Cs, Ca, Mg hydroxides, which may be present in the mixture in amounts of from 0 to 10% by weight, based on the reaction mixture. However, in most cases it is advantageous to carry out the hydrogenation without the use of inorganic basis.

[0050] The dinitrile hydrogenation over the modified catalyst is preferably carried out under a hydrogen pressure of from 1 to 200 bar, in particular from 2 to 50 bar.

[0051] The dinitrile hydrogenation over the modified catalyst is preferably carried out in the temperature range from 30 to 160 °C, in particular from 40 to 100 °C.

[0052] Using K3PO4 as a catalyst modifier

[0053] As it is known from the state of the art - particularly from BASF application - that CS2CO3, K2CO3, Li2CO3, Ca(OAc)2 2 H2O, and Mg2(OAc)2 can be used to modify Raney Ni (RNi) catalyst for the effective hydrogenation of dinitriles. On the contrary, in this application a more efficient compound, potassium phosphate (K3PO4) was employed for the purpose of modifying the hydrogenation catalyst.

[0054] Concurrently, our findings demonstrate that the catalyst performance is influenced in an unforeseen manner by the K3PO4 modifier. Comparing the results obtained (e.g. in Examples 14 to 17 and 35) with those described in the BASF application (Examples 1-5) reveals that the use of the modifier K3PO4, even in the absence of ammonia, resulted in overall aminocapronitrile and hexamethylenediamine selectivities that were 5-9% higher than those obtained with the modifiers used by BASF in the presence of ammonia, see Table 2 (S=selectivity, Y= yield). Table 2

[0055] When the modifier according to our invention and ammonia are used (under the same experimental conditions as those employed in BASF application), the aminocapronitrile selectivity is also markedly higher, with a range of 8-23% greater than that observed in the BASF experiments. Additionally, no (or very small amount) side products were formed in these experiments, whereas side products were formed in 5-10% known from the literature.

[0056] The modifiers applied in the examples in the BASF application (alkaline metal carbonates and alkaline-earth metal acetates) during the reaction may decompose with the evolution of gases (e.g. carbon dioxide which can impede the reaction), especially when no ammonia is applied, i.e. the pH is lower. Further, a small amount of gas formation is enough to weaken the bonding of the modifier to the catalyst surface, leading to layer ablation. This can be a reason why the prior art modifiers are less strongly deposited on the surface and may erode from the catalyst surface with ease. The aforementioned properties are evident from the elevated amounts of byproducts, even in the presence of ammonia, and the decline in the overall selectivity for aminocapronitrile and hexamethylenediamine. As the modifiers applied in the BASF examples are more susceptible to erosion from the catalyst surface, they cannot be reused in successive cycles. Furthermore, the catalysts cannot undergo pretreatment at elevated temperatures due to the decomposition of the modifiers (resulting in evolution of CO2).

[0057] To make an optimal catalyst modifier, one aspect is the pH of the solution. The pH of magnesium acetate solution is pH = 6-8.5, pH of calcium acetate solution is pH = 7.6, pH of potassium acetate solution is pH = 7-8, pH of sodium acetate solution pH = 7.5-9, and pH of sodium formate is pH = 6.5-9. The pH values of these compounds range from 7 to 8.5, with the exception of K-formate, which has a pH range of pH = 6-8. Na2(OAc)2and K2(OAc)2have pH values of pH = 6.5-9. These compounds are neutral to slightly alkaline in nature. It is evident that none of these compounds can act as effective modifiers, given that the reaction in question necessitates the presence of a strongly basic medium. Consequently, these carbonate type catalyst modifiers have the effect of increasing the formation of byproducts.

[0058] Among the carbonates, the most alkaline are NaHCCh (pH = 8.4-8.6), KHCO3 (pH = 8.3-8.5), Na2CO2(pH = 11.5), and K2CO3 (pH = 11.6). Based on their basicity, these catalysts appear to be suitable modifiers. The experiments (see example 36 and 37 for K2CO3), however, indicate otherwise. These compounds do not adhere well to the catalyst surface, and at higher conversions, they degrade in selectivity as they degrade and the formation of byproducts becomes significant (see examples 40 and 41).

[0059] In the case of phosphates, the aqueous solutions of KH2PO4 (pH = 4.4-4.7) and NaH2PO4 (pH = 4.5) exhibit slight acidity, which is particularly detrimental to the hydrogenation of dinitriles and promotes the formation of undesirable byproducts.

[0060] The aqueous solutions of K2HPO4 (pH = 9.1-9.3) and Na2HPO4 (pH = 8.9-9.2) are slightly alkaline. The catalysts modified with K2HPO4 perform better in some parameters than the BASF catalysts (see examples 24 and 31, overall yield and overall selectivity), but ACN yield and selectivity are relatively low.

[0061] K3PO4 (pH = 12) and ISfePC (pH = 12) are strongly alkaline. Contrary to expectations, ISfePC is an ineffective catalyst modifier (see Table 3). This is likely due to its inability to adhere effectively to the catalyst surface and / or the smaller size of the Na ion, which may result in an imperfect structure of the adhered layer (but this difference in the adsorption could not be foreseen). Meanwhile, K3PO4 has been demonstrated to be an exceptional catalyst modifier. The negative effect of using Na instead of K in the phosphate salts is demonstrated in Table 3.

[0062] Table 3: Hydrogenation reactions conducted using different catalysts modifiers (conditions: m(cat.) = 6 g, T= 65°C, r =1500 rpm, VADN=100 ml). p(H2) OT(NH3) Conv. Sei. Sei. Yield Yield SSel. EYield modifier HMD ACN HMD ACN ACN+HMD ACN+HMD

[0063] One might expect that KOH and NaOH (pH = 14), as the strongest alkaline solutions, would be the most effective modifiers. Experimental results, however, indicate that because they do not adhere effectively to the catalyst surface, it has a diminished effect compared to that of K3PO4. It has been demonstrated that KOH and NaOH can react with the aluminum content of RNi catalysts, resulting in the leaching of aluminum. This process may impede surface adhesion and the formation of an optimal layer structure.

[0064] A further notable attribute of the catalyst modifier K3PO4 is its exceptional performance in comparison to the modifiers used in the examples of the BASF application. This compound does not decompose via gas evolution at temperatures exceeding 1340 °C. It is also observed that the compound is deposited (adsorbed) effectively on the catalyst surface and remains there for an extended period. The full adiponitrile conversion results in only trace amounts of side products, even in the absence of ammonia, and the remarkable overall selectivity to aminocapronitrile (ACN) and hexamethylenediamine (HMD), is attributable, at least in part, to the excellent adherence of K3PO4 to the surface. The evolution of hydrogenation does not erode K3PO4 from the catalyst surface, allowing the modified catalyst to be reused in multiple cycles. The high thermal stability of catalysts modified by K3PO4 enables them to withstand significant thermal pretreatment, allowing for their use in a broader range of reactions compared to other modifiers. Similar good results were achieved by K4P2O7. Consequently, K3PO4 and K4P2O7 are surprisingly effective catalyst modifiers due to their strong basicity and favorable adhesion to the catalyst surface, and they form an optimal layer structure (where K3PO4 is more preferred). There is no any hint in the BASF application for these surprisingly positive effects because the BASF application focuses on the carbonate and acetate salts (the phosphates are only mentioned in a longer list and the pyrophosphate are not mentioned at all).

[0065] Running the experiments with the highly efficient K3PO4 modification on RCo catalyst and 40%Ni / A12O3 catalyst, also result in high conversion and selectivity values, see Examples 29 and 30, respectively.

[0066] Catalytic hydrogenation of adiponitrile using K3PO4 with or without ammonia

[0067] In the catalytic hydrogenation of adiponitrile on industrial scale, the appropriately high selectivity of the two useful main products - that is aminocapronitrile (ACN) and hexamethylenediamine (HMD) - is the aim, where the ACN is the more valuable product. According to the present invention, it the high selectivity to ACN and HMD can be achieved without the use of ammonia. However, the selectivity to ACN can be enhanced by the use of ammonia. In this embodiment the amount of ammonia in the reaction mixture is about 0.01-80% by weight based on the dinitrile, preferably in an amount of from 0.01-60% by weight based on the dinitrile. It means that the in the preferred embodiment smaller amount of ammonia is enough to achieve very good results.

[0068] It is important to note that in the literature, ammonia is always used beside modifier. Whereas in the present application, in the absence of ammonia (see examples 14., 15., 18., 19., 20., 21., 22., 23., 24., 25., 26., 28., 29., 30., 31., 32., 33., 34), the byproducts are formed in small quantity, together with a notable increase in the overall selectivity for ACN and HMD. In the reaction according to the invention (Table , Example 14), very good selectivity and yield for ACN+HMD results were obtained, compared to the results of Example 12, where unmodified Raney nickel catalyst was applied.

[0069] As it comes from Example 17, it is possible to enhance the selectivity and the yield for ACN+HMD results by the use of ammonia, moreover, to enhance the ACN selectivity, too, compared to Example 13, where unmodified Raney nickel catalyst was applied.

[0070] That is, in the absence of ammonia, the sole effective suppressant of byproduct formation is the K-phosphate modifier, which also predominantly yields the two main products (ACN and HMD). The presence of both the modifier and ammonia increases the selectivity of the more valuable semi -hydrogenated form (ACN), suppressing the less valuable HMD.

[0071] The effectiveness of the modified catalyst according to the invention compared to non-modified catalyst is demonstrated in Table 4.

[0072] Table 4: Hydrogenation reactions carried out by different catalysts (conditions: m(cat.) _ = 6 g, T= 65°C, r = 1500 rpm, VADN=100 ml) _

[0073] 1 C Yield

[0074] Ex. modifier cony. CN+HMD

[0075] 12 - - 98.11 38.08 32.48 37.36 31.87 70.56 69.23

[0076] 13 - 7.48 g 98.10 44.90 44.80 44.10 43.90 89.70 88.00

[0077] 14 10g / 50ml K3PO4 - 99.24 49.80 49.80 49.42 49.42 99.60 98.84

[0078] 17 10g / 50ml K3PO4 30 100.00 28.20 71.80 28.20 71.80 100.00 100.00

[0079] Using K2HPO4 and KH2PO4 as a catalyst modifier

[0080] As demonstrated in Table 5, modifying the catalyst with K2HPO4 and KH2PO4 results in better selectivity and yield at 98-99% conversions compared to unmodified ones. Adding 7.48 g ammonia to the reaction mixture has been observed to facilitate the formation of ACN while simultaneously reducing the amount of byproducts formed. It should be noted, however, that despite their similarity to K3PO4, phosphates containing hydrogen - such as KH2PO4 and K2HPO4, especially the former - may decompose during the reaction and are not very well adsorbed on the surface.

[0081] Using K4P2O7 also results in high selectivity and yield, and comparing with KH2PO4 and K2HPO4, it can drive the reaction towards ACN formation. The most effective modifiers are K3PO4 and K4P2O7 and a mixture of the two. In reactions involving a catalyst modified with the compounds listed above, together with the addition of ammonia result in an increase in the selectivity and yield of the more valuable of the two main products, aminocapronitrile, while simultaneously reducing the formation of undesirable byproducts to below the detection limit. Table 5: Hydrogenation reactions carried out by KH2PO4 or K2HPO4-modified Raney

[0082] Nickel catalysts (conditions: m(cat.) = 6 g, r = 1500 rpm, VADN=100 ml),

[0083] Using K4P2O7 as a catalyst modifier

[0084] The aqueous solution of K4P2O7 (K-pyrophosphate, pH = 10.3) exhibits weak alkalinity, yet it displays remarkable efficiency as a catalyst modifier. This is likely attributed to its robust adhesion to the catalyst surface and the structural integrity of the layer formed.

[0085] It is evident that K3PO4 and K4P2O7 are more effective as catalyst modifiers when used alone, without ammonia, than the modifiers known from the state of the art (experiments in BASF application) when ammonia is present. The differing pH of the aqueous solution of the modifiers, the varying degree of adhesion to the catalyst surface, and the differing structure of the adherent layer all contribute to this conclusion. The use of a modified catalyst according to the invention, such as K3PO4 and / or K4P2O7, results in a less exothermic hydrogenation reaction, that requires less cooling, which in turn leads to energy savings.

[0086] Optimizing parameters for obtaining ACN with high yield and selectivity

[0087] In the production of nylon / polyamides, ACN can be polymerized independently, whereas HMD can only be polymerized in conjunction with adipic acid. The results of the Example 41 experiment demonstrate that by modifying the catalyst and conducting the reaction in the presence of ammonia, it is possible to obtain ACN with 99% selectivity up to a very high conversion value of 80%, while HMD is only approximately 1% selective. If the reaction is terminated at this conversion, the more valuable ACN product can be obtained with a maximum yield of 80%. This result has an extraordinary importance in the practice. EXAMPLES

[0088] Catalyst modification:

[0089] Example 1

[0090] 8 g K3PO4 modifier was dissolved in 50 ml distilled water (concentration, c = 160 g / 1) and 6 g wet catalyst was suspended in the solution and stirred at room temperature for 1 hour. After modification the suspension was decanted and the catalyst was washed twice with 20 ml ethanol. The potassium content of the catalyst was 3.8 % by weight.

[0091] Example 2

[0092] 10 g K3PO4 modifier was dissolved in 50 ml distilled water (c = 200 g / 1) and 6 g wet catalyst was suspended in the solution and stirred at room temperature for 1 hour. After modification the suspension was decanted and the catalyst was washed twice with 20 ml ethanol. The potassium content of the catalyst was 5.5 % by weight.

[0093] Example 3

[0094] 10 g K3PO4 modifier was dissolved in 40 ml distilled water (c = 250 g / 1) and 7 g wet catalyst was suspended in the solution and stirred at room temperature for 1 hour. After modification the suspension was decanted and the catalyst was washed twice with 20 ml ethanol. The potassium content of the catalyst was 6.7 % by weight.

[0095] Example 4

[0096] 10 g K3PO4 modifier was dissolved in 50 ml distilled water (c = 200 g / 1) and 6 g wet catalyst was suspended in the solution and stirred at room temperature for 1 hour. After modification the suspension was decanted. The potassium content of the catalyst was 6.2 % by weight.

[0097] Example 5

[0098] 10 g K3PO4 modifier was dissolved in 50 ml distilled water (c = 200 g / 1) and 6 g wet catalyst was suspended in the solution and stirred at room temperature for 1 hour. After modification the suspension was filtered off under a nitrogen atmosphere. The potassium content of the catalyst was 2.9 % by weight. Example 6

[0099] 10 g K3PO4 modifier was dissolved in 50 ml distilled water (c = 200 g / 1) and 6 g wet catalyst was suspended in the solution and stirred at room temperature for 24 hours under a nitrogen atmosphere. After modification the suspension was decanted and the catalyst was washed twice with 20 ml methanol. The potassium content of the catalyst was 5.6 % by weight.

[0100] Example 7

[0101] 4 g K3PO4 modifier was dissolved in 20 ml distilled water (c = 200 g / 1) and 6 g wet catalyst was suspended in the solution and stirred at room temperature for 1 hour. After modification the suspension was decanted and the catalyst was washed twice with 20 ml ethanol. The potassium content of the catalyst was 5.3 % by weight.

[0102] Example 8

[0103] 10 g K2HPO4 modifier was dissolved in 50 ml distilled water (c = 200 g / 1) and 6 g wet catalyst was suspended in the solution and stirred at room temperature for 1 hour. After modification the suspension was decanted and the catalyst was washed twice with 20 ml ethanol. The potassium content of the catalyst was 4.9 % by weight.

[0104] Example 9

[0105] 10 g K4P2O7 modifier was dissolved in 50 ml distilled water (c = 200 g / 1 alkali metal pyrophosphate solution) and 6 g wet catalyst was suspended in the solution and stirred at room temperature for 1 hour. After modification the suspension was decanted and the catalyst was washed twice with 20 ml ethanol. The potassium content of the catalyst was 5.4 % by weight.

[0106] Example 10

[0107] 8 g K3PO4, 1 g K2HPO4 and 0.01 g KOH modifier was dissolved in 50 ml distilled water and 6 g wet catalyst was suspended in the solution and stirred at room temperature for 0.5 hour. After modification the suspension was decanted and the catalyst was washed twice with 25 ml ethanol. The potassium content of the catalyst was 4.6 % by weight. Example 11

[0108] 8 g K3PO4 and 2 g K4P2O7 modifier was dissolved in 50 ml distilled water and 6 g wet catalyst was suspended in the solution and stirred at room temperature for 0.5 hour. After modification the suspension was decanted and the catalyst was washed twice with 30 ml ethanol. The potassium content of the catalyst was 5.2 % by weight.

[0109] Hydrogenation of dinitrile:

[0110] Control Example 12 - UNMODIFIED CATALYST, WITHOUT AMMONIA

[0111] A 300 ml stainless steel reactor was charged with 100 ml (0.88 mol) adiponitrile, and 6 g wet unmodified Raney nickel catalyst. The reaction was run for 2 hours and 24 minutes (2.4 hours) under 20 bar hydrogen pressure at 65 °C, and the reaction mixture was stirred at a rate of 1500 rpm. The final conversion was 98.1 % and the overall selectivity to aminocapronitrile (ACN) and hexamethylenediamine (HMD) was 70.5 %. The overall yield of ACN and HMD was 69.2 %. The yield of ACN was 31.9 %, at a conversion of 98.1 % and a selectivity to ACN of 32.5 %. t Conversion Selectivity (%) Yield (%)

[0112] 0.17 19.31 0.00 93.79 0.00 18.11

[0113] 0.33 37.50 3.60 83.95 1.35 31.48

[0114] 0.50 53.13 4.82 80.14 2.56 42.58

[0115] 1.00 82.81 20.78 56.82 17.21 47.05

[0116] 1.50 90.83 28.11 45.14 25.53 41.00

[0117] 2.00 95.20 34.49 37.27 32.83 35.48

[0118] 2.40 98.11 38.08 32.48 37.36 31.87

[0119] Concentration (%) t (h) HMD ACN ADN "others"

[0120] 0 0 0 100 0

[0121] 0.17 0.00 18.11 80.69 1.20

[0122] 0.33 1.35 31.48 62.50 4.67

[0123] 0.50 2.56 42.58 46.87 7.99

[0124] 1.00 17.21 47.05 17.19 18.55

[0125] 1.50 25.53 41.00 9.17 24.30

[0126] 2.00 32.83 35.48 4.80 26.89

[0127] 2.40 37.36 31.87 1.89 28.88

[0128] Control Example 13 - UNMODIFIED CATALYST, WITH AMMONIA

[0129] The reactor was charged with 100 ml (0.88 mol) adiponitrile, 6 g wet unmodified Raney nickel catalyst, and 7.48 g (0.44 mol) ammonia. The reaction was run for 2 hours under 20 bar hydrogen pressure at 65 °C. The reactor was stirred at a rate of 1500 rpm. The final conversion was 98.1 %, overall selectivity to ACN and HMD was 89.7 %. The overall yield of ACN and HMD was 88.0 %. The selectivity to ACN was 44.8 %, and the yield of ACN was 43.9 % at this conversion. t Conversion Selectivity (%) Yield (%)

[0130] 0.17 22.12 0.45 97.83 0.10 21.64

[0131] 0.33 46.39 7.18 91.89 3.33 42.63

[0132] 0.50 61.51 14.36 83.24 8.83 51.20

[0133] 1.00 84.50 26.46 67.86 22.36 57.34

[0134] 2.00 98.10 44.94 44.78 44.09 43.93

[0135] Concentration (%)

[0136] 0 0 0 100 0

[0137] 0.17 0.10 21.64 77.88 0.38

[0138] 0.33 3.33 42.63 53.61 0.43

[0139] 0.50 8.83 51.20 38.49 1.48

[0140] 1.00 22.36 57.34 15.50 4.80

[0141] 2.00 44.09 43.93 1.90 10.08

[0142]

[0143] Example 14 (without ammonia)

[0144] A 300 ml stainless steel reactor was charged with 100 ml adiponitrile, and 6 g wet Raney nickel catalyst modified with 200 g / 1 K3PO4 solution as given in Example 2. The reaction was run for 3.15 hours under 20 bar hydrogen at 65 °C and the reaction was stirred at 1500 rpm. At the final conversion rate of 99.2 %, the overall selectivity to ACN and HMD was 99.6%. The overall yield of ACN and HMD was 98.8 %. The yield of ACN was 49.4 % at this conversion, and a selectivity to ACN of 49.8 %. At a conversion rate of 80.5 %, the selectivity to ACN was 78.0 %, i.e. at a relatively high conversion a very good selectivity to ACN could be achieved (much higher than in Control Example 12 (without ammonia)). t Conversion Selectivity (%) Yield (%)

[0145] 0.17 9.14 1.97 98.03 0.18 8.96

[0146] 0.33 16.39 3.54 96.46 0.58 15.81

[0147] 0.50 24.79 4.84 95.16 1.20 23.59

[0148] 1.00 47.42 9.89 89.98 4.69 42.67

[0149] 2.00 80.48 22.15 77.71 17.83 62.54

[0150] 3.00 97.43 46.78 52.87 45.58 51.51

[0151] 3.15 99.24 49.80 49.80 49.42 49.42 Concentration (%)

[0152] 0 0 0 100 0

[0153] 0.17 0.18 8.96 90.86 0.00

[0154] 0.33 0.58 15.81 83.61 0.00

[0155] 0.50 1.20 23.59 75.21 0.00

[0156] 1.00 4.69 42.67 52.58 0.06

[0157] 2.00 17.83 62.54 19.52 0.11

[0158] 3.00 45.58 51.51 2.57 0.34

[0159] 3.15 49.42 49.42 0.76 0.40

[0160] Please note that the above table and diagram available practically for all the examples but for sparing with the volume of the description they are not inserted in every example. Example 15 (without ammonia)

[0161] A 300 ml stainless steel reactor was charged with 100 ml adiponitrile, and 6 g wet Raney nickel catalyst modified with 200 g / 1 K3PO4 solution as given in Example 2. The reaction was run for 3.5 hours under 10 bar hydrogen at 65 °C and the reaction was stirred at 1500 rpm. At the final conversion rate of 95.9 %, the overall selectivity to ACN and HMD was 99.7 %. The overall yield of ACN and HMD was 95.6 %. The yield of ACN was 56.4 % at this conversion, and a selectivity to ACN of 58.8 %. The results are much better than in Control Example 12 (without ammonia).

[0162] Example 16 (with ammonia)

[0163] A 300 ml stainless steel reactor was charged with 100 ml adiponitrile, 6 g wet Raney nickel catalyst modified with 200 g / 1 K3PO4 (Example 2), and 7.48 g (0.44 mol) ammonia. The reaction was run for 3.3 hours under 20 bar hydrogen at 65 °C, and the reaction was stirred at a rate of 1500 rpm. The overall yield of ACN and HMD was 99.5 %, at the final conversion of 99.5 % and an overall selectivity to ACN and HMD of 100 %. At the final conversion of 99.5 % the selectivity to ACN was 60.4 %. The yield of ACN was 60.1 %. At a conversion rate of 80.5 %, the selectivity to ACN was 82.4 %. The results are much better than in Control Example 13 (with ammonia). t Conversion Selectivity (%) Yield (%)

[0164] 0 0 0 0 0 0

[0165] 0.17 9.06 0.77 99.23 0.07 8.99

[0166] 0.33 19.36 2.63 97.37 0.51 18.85

[0167] 0.50 28.65 4.12 95.88 1.18 27.47

[0168] 1.00 51.44 8.09 91.91 4.16 47.28

[0169] 2.00 80.47 17.63 82.37 14.19 66.28

[0170] 3.00 97.43 33.46 66.54 32.60 64.83

[0171] 3.30 99.55 39.59 60.41 39.41 60.14 Concentration (%) t (h) HMD ACN ADN "others"

[0172] 0 0 0 100 0

[0173] 0.17 0.07 8.99 90.94 0.00

[0174] 0.33 0.51 18.85 80.64 0.00

[0175] 0.50 1.18 27.47 71.35 0.00

[0176] 1.00 4.16 47.28 48.56 0.00

[0177] 2.00 14.19 66.28 19.53 0.00

[0178] 3.00 32.60 64.83 2.57 0.00

[0179] 3.30 39.41 60.14 0.45 0.00

[0180] Example 17 (with ammonia)

[0181] The 300 ml stainless steel reactor was charged with 100 ml adiponitrile, 6 g wet Raney nickel catalyst modified with 200 g / 1 K3PO4 (Example 2), and 30 g (1.76 mol) ammonia. The reaction was run for 5 hours under 20 bar hydrogen at 65 °C, and the reaction was stirred at a rate of 1500 rpm. The overall yield of ACN and HMD was 100 %, at a conversion of 100 % and an overall selectivity to ACN and HMD of 100 %. The selectivity to ACN was 71.8%. The results are much better than in Control Example 13 (with ammonia), see especially the practically 100 % conversion. t Conversion Selectivity (%) Yield (%)

[0182] 0.17 4.71 0.00 100.00 0.00 4.71

[0183] 0.33 15.50 0.00 100.00 0.00 15.50

[0184] 0.50 24.66 0.00 100.00 0.00 24.66

[0185] 1.00 43.26 1.87 98.13 0.81 42.45

[0186] 2.00 66.31 4.93 95.07 3.27 63.04

[0187] 3.00 81.00 15.19 84.81 12.30 68.70

[0188] 4.00 91.81 22.37 77.63 20.54 71.27

[0189] 5.00 100.00 28.20 71.80 28.20 71.80

[0190] C oncentrati on(%)

[0191] 0 0 0 100 0

[0192] 0.17 0.00 4.71 95.29 0.00

[0193] 0.33 0.00 15.50 84.50 0.00

[0194] 0.50 0.00 24.66 75.34 0.00

[0195] 1.00 0.81 42.45 56.74 0.00

[0196] 2.00 3.27 63.04 33.69 0.00

[0197] 3.00 12.30 68.70 19.00 0.00

[0198] 4.00 20.54 71.27 8.19 0.00

[0199] 5.00 28.20 71.80 0.00 0.00

[0200] Example 18 (without ammonia)

[0201] The procedure of Example 14 was repeated except that the Raney nickel catalyst was modified with 160 g / 1 K3PO4 solution as given in Example 1 and the reaction time was 4 hours. The overall yield of ACN and HMD was 98.5 %, at a conversion of 98.9 % and an overall selectivity to ACN and HMD of 99.6 %. The yield of ACN was 49.0 % at this conversion and the selectivity to ACN of 49.5 %. The results are much better than in Control Example 13 (with ammonia). t Conversion Selectivity (%) Yield (%)

[0202] 0.17 6.63 1.21 98.79 0.08 6.55

[0203] 0.33 18.84 4.19 95.81 0.79 18.05

[0204] 0.50 29.78 6.08 93.92 1.81 27.97

[0205] 1.00 52.64 10.47 89.53 5.51 47.13

[0206] 2.00 81.23 24.54 75.24 19.93 61.12

[0207] 3.00 92.59 36.24 63.51 33.55 58.80

[0208] 4.00 98.87 50.09 49.47 49.52 48.91 Example 19 (without ammonia)

[0209] The procedure of Example 14 was repeated except that the Raney nickel catalyst was modified with 250 g / 1 K3PO4 solution as given in Example 3 for 3 hours. The overall yield of ACN and HMD was 64.0 %, at a conversion of 64.1 % and an overall selectivity to ACN and HMD of 99.8 %. The yield of ACN was 52.7% at this conversion and the selectivity to ACN of 82.3 %.

[0210] Example 20 (without ammonia)

[0211] The procedure of Example 14 was repeated except that the Raney nickel catalyst was modified with 200 g / 1 K3PO4 solution as given in Example 4 for 3 hours. The overall yield of ACN and HMD was 83.3 %, at a conversion of 83.4 % and an overall selectivity to ACN and HMD of 99.9 %. The yield of ACN was 65.3 % at this conversion and the selectivity to ACN of 78.3 %.

[0212] Example 21 (without ammonia)

[0213] The procedure of Example 14 was repeated except that the Raney nickel catalyst was modified with 200 g / 1 K3PO4 solution as given in Example 5 for 2.8 hours. The overall yield of ACN and HMD was 92.9 %, at a conversion of 99.0 % and an overall selectivity to ACN and HMD of 93.8 %. The yield of ACN was 41.9 % at this conversion and the selectivity to ACN of 42.3 %.

[0214] Example 22 (without ammonia)

[0215] The procedure of Example 14 was repeated except that the Raney nickel catalyst was modified with 200 g / 1 K3PO4 solution as given in Example 6 for 3.1 hours. The overall yield of ACN and HMD was 98.1 %, at a conversion of 98.5 % and an overall selectivity to ACN and HMD of 99.6 %. The yield of ACN was 49.2 % at this conversion and the selectivity to ACN of 49.9 %.

[0216] Example 23 (without ammonia)

[0217] The procedure of Example 14 was repeated except that the Raney nickel catalyst was modified with 200 g / 1 K3PO4 solution as given in Example 7 for 3 hours. The overall yield of ACN and HMD was 98.5 %, at a conversion of 99.3 % and an overall selectivity to ACN and HMD of 99.2 %. The yield of ACN was 45.0 % at this conversion and the selectivity to ACN of 45.3 %.

[0218] Example 24 (without ammonia)

[0219] The procedure of Example 14 was repeated except that the Raney nickel catalyst was modified with 200 g / 1 K2HPO4 solution as given in Example 8 for 2.4 hours. The overall yield of ACN and HMD was 97.1 %, at a conversion of 98.3 % and an overall selectivity to ACN and HMD of 98.8 %. The yield of ACN was 30.0 % at this conversion and the selectivity to ACN of 30.5 %. Accordingly, the selectivity to ACN is poorer compared to the Example 14.

[0220] Example 25 (without ammonia)

[0221] The procedure of Example 14 was repeated except that the Raney nickel catalyst was modified with 200 g / 1 K4P2O7 solution as given in Example 9 for 3 hours. The overall yield of ACN and HMD was 97.7 %, at a conversion of 98.5 % and an overall selectivity to ACN and HMD of 99.2 %. The yield of ACN was 41.7 % at this conversion and the selectivity to ACN of 42.3 %.

[0222] Example 26 (without ammonia)

[0223] A 300 ml stainless steel reactor was charged with 10 ml adiponitrile, 100 ml methanol, and 1 g Raney nickel catalyst (comprising 1.5 % by weight of Cr (as promoter) with respect to the Ni) modified with 250 g / 1 K3PO4 solution. The reaction was run for 0.5 hour under 35 bar hydrogen at 80 °C, and the reaction mixture was stirred at 1500 rpm. The overall yield of ACN and HMD was 98.0 %. The conversion was 99.5 % and the overall selectivity to ACN and HMD was 98.5 %. The yield of ACN was 30.7 % at this conversion and the selectivity to ACN of 30.8 %.

[0224] Example 27 (without ammonia + NasPCU is the modifier)

[0225] A 300 ml stainless steel reactor was charged with 10 ml adiponitrile, 100 ml ethanol, and 1 g Raney nickel catalyst modified with 150 g / 1 NasPCh solution according to the method given in Example 1. The reaction was run for 0.5 hour under 35 bar hydrogen at 75 °C, and the reaction mixture was stirred at 1500 rpm. The overall yield of ACN and HMD was 54.5 %. The conversion was 61.0 % and the overall selectivity to ACN and HMD was 89.4 %. The yield of ACN was 38.3 % at this conversion and the selectivity to ACN of 62.8 %.

[0226] Example 28 (without ammonia)

[0227] A 300 ml stainless steel reactor was charged with 100 ml adiponitrile, 0.01 g KOH, 0.5 ml ethanol, 0.5 ml water, 95 g hexamethylenediamine as solvent, and 6 g Raney nickel catalyst modified with 200 g / 1 K3PO4 solution (Example 2). The reaction was run for 3.7 hours under 20 bar hydrogen at 55 °C, and the reaction mixture was stirred at 1500 rpm. The overall yield of ACN and HMD was 99.6 %. The conversion was 99.6 % and the overall selectivity to ACN and HMD was 100 %. The yield of ACN was 70.6 % at this conversion and the selectivity to ACN of 70.9 %.

[0228] Example 29 (without ammonia + RCo catalyst)

[0229] A 300 ml stainless steel reactor was charged with 100 ml adiponitrile, and 6 g wet Raney cobalt catalyst modified with 200 g / 1 K3PO4 solution as given in Example 2. The reaction was run for 4 hours under 20 bar hydrogen at 65 °C and the reaction was stirred at 1500 rpm. At a conversion rate of 99.1 %, the overall selectivity to ACN and HMD was 99.6 %. The overall yield of ACN and HMD was 98.7 %. The yield of ACN was 42.5 % at this conversion, and a selectivity to ACN of 42.9 %.

[0230] / Conversion Selectivity (%) Yield (%)

[0231] (h) (%) HMD ACN HMD ACN

[0232] 0 0 0 0 0 0

[0233] 0.17 7.46 2.14 97.86 0.16 7.30

[0234] 0.33 17.64 4.02 95.98 0.71 16.93

[0235] 0.50 27.85 7.54 92.46 2.10 25.75

[0236] 1.00 52.07 11.79 88.21 6.14 45.93

[0237] 2.00 80.33 24.47 75.43 19.66 60.59

[0238] 3.00 93.67 36.04 63.76 33.76 59.72

[0239] 4.00 99.11 56.71 42.93 56.21 42.55

[0240] Example 30 (without ammonia)

[0241] A 300 ml stainless steel reactor was charged with 100 ml adiponitrile, and 6 g 40% Ni / AhCE catalyst modified with 160 g / 1 K3PO4 solution as given in Example 1. The reaction was run for 3 hours under 20 bar hydrogen at 65 °C and the reaction was stirred at 1500 rpm. At a conversion rate of 99.1 %, the overall selectivity to ACN and HMD was 99.4 %. The overall yield of ACN and HMD was 98.5 %. The yield of ACN was 48.2 % at this conversion, and a selectivity to ACN of 48.6 %.

[0242] / Conversion Selectivity (%) Yield (%)

[0243] (h) (%) HMD ACN HMD ACN

[0244] 0 0 0 0 0 0

[0245] 0.17 7.51 2.13 97.87 0.16 7.35

[0246] 0.33 18.84 4.19 95.81 0.79 18.05

[0247] 0.50 30.09 7.05 92.95 2.12 27.97

[0248] 1.00 57.24 11.20 88.80 6.41 50.83

[0249] 2.00 82.29 26.94 72.68 22.17 59.81

[0250] 3.00 99.14 50.78 48.58 50.34 48.16

[0251] Example 31 (without ammonia)

[0252] A 300 ml stainless steel reactor was charged with 100 ml adiponitrile, and 6 g wet Raney nickel catalyst modified with K3PO4, K2HPO4 and KOH mixture solution as given in Example 10. The reaction was run for 3 hours under 20 bar hydrogen at 65 °C and the reaction was stirred at 1500 rpm. At a conversion rate of 98.6 %, the overall selectivity to ACN and HMD was 99.4 %. The overall yield of ACN and HMD was 98.0 %. The yield of ACN was 43.9 % at this conversion, and a selectivity to ACN of 44.5 %.

[0253] Example 32 (without ammonia + modifier mixture)

[0254] A 300 ml stainless steel reactor was charged with 100 ml adiponitrile, and 6 g wet Raney nickel catalyst (comprising 1.5 % by weight of Cr (as promoter) with respect to the Ni) modified with K3PO4 and K4P2O7 mixture solution as given in Example 11. The reaction was run for 3.1 hours under 20 bar hydrogen at 65 °C and the reaction was stirred at 1500 rpm. At a conversion rate of 98.3 %, the overall selectivity to ACN and HMD was 99.5 %. The overall yield of ACN and HMD was 97.8 %. The yield of ACN was 46.4 % at this conversion, and a selectivity to ACN of 47.2 %.

[0255] Example 33 (without ammonia + modifier mixture)

[0256] A 100 ml stainless steel reactor was charged with 35 ml adiponitrile, 10 ml water, 2 g wet Raney nickel catalyst modified with 200 g / 1 K3PO4 solution (Example 2), 0.01 g KOH and 0.1 g K3PO4. The reaction was run for 1 hour under 20 bar hydrogen pressure at 60 °C, and the reaction mixture was stirred at a rate of 1000 rpm. The selectivity of ACN was 72.2 % at a conversion of 74.3 %.

[0257] Example 34 (without ammonia)

[0258] A 100 ml stainless steel reactor was charged with 45 ml adiponitrile, 15.7 g HMD, 10 ml water, 2 g wet Raney nickel catalyst, 0.01 g NaOH and 0.07 g K3PO4. The reaction was run for 1.5 hours under 20 bar hydrogen pressure at 55 °C, and the reaction mixture was stirred at a rate of 1000 rpm. The selectivity of ACN was 77.4 % at a conversion of 75.8%.

[0259] Example 35 (with ammonia, high ACN selectivity and yield)

[0260] The 300 ml stainless steel reactor was charged with 50 ml adiponitrile (0.44 mol), 6 g wet Raney nickel catalyst modified with 200 g / 1 K3PO4 according to Example 2 and 100 g ammonia (5.88 mol). The reaction was run for 3.8 hours under 20 bar hydrogen at 65 °C, and the reaction was stirred at a rate of 1500 rpm. At 80.82% conversion, the ACN selectivity is 99.01 with 80% yield, which are extremely good results. t Conversion Selectivity (%) Yield (%)

[0261] 0.17 7.62 0.00 100.00 0.00 7.62

[0262] 0.33 20.44 0.00 100.00 0.00 20.44

[0263] 0.50 30.79 0.00 100.00 0.00 30.79

[0264] 1.00 54.26 0.00 100.00 0.00 54.26

[0265] 2.00 80.82 0.99 99.01 0.80 80.02

[0266] 3.00 93.54 6.63 93.37 6.20 87.34

[0267] 3.80 99.08 11.18 88.82 11.08 88.00

[0268] Concentration(%) t (h) HMD ACN ADN "others" 0 0 0 100 0

[0269] 0.17 0.00 7.62 92.38 0.00

[0270] 0.33 0.00 20.44 79.56 0.00

[0271] 0.50 0.00 30.79 69.21 0.00

[0272] 1.00 0.00 54.26 45.74 0.00

[0273] 2.00 0.80 80.02 19.18 0.00

[0274] 3.00 6.20 87.34 6.46 0.00

[0275] 3.80 11.08 88.00 0.92 0.00

[0276] Example 36, Control Example (modification with K2CO3, without ammonia)

[0277] A 300 ml stainless steel reactor was charged with 100 ml adiponitrile, and 6 g wet Raney nickel catalyst modified with 200 g / 1 K2CO3 solution as given in Example 2 but K2CO3 was applied as modifier instead of K3PO4. The reaction was run for 2 hours under 20 bar hydrogen at 65 °C and the reaction was stirred at 1500 rpm. At the final conversion rate of 98.25%, the overall selectivity to ACN and HMD was 77.7%. The overall yield of ACN and HMD was 76.3%. The yield of ACN was 30.9% at this conversion, and a selectivity to ACN of 31.4%. It can be seen that these results are much poorer than the same in e.g. Example 14. t Conversion Selectivity (%) Yield (%)

[0278] 0.17 11.52 3.73 96.01 0.43 11.06

[0279] 0.33 29.12 7.80 88.63 2.27 25.81

[0280] 0.50 46.19 11.21 83.31 5.18 38.48

[0281] 1.00 78.36 22.38 67.00 17.54 52.50

[0282] 2.00 98.25 46.26 31.45 45.45 30.90

[0283] Concentrati on(%)

[0284] 0 0 0 100 0

[0285] 0.17 0.43 11.06 88.48 0.03

[0286] 0.33 2.27 25.81 70.88 1.04

[0287] 0.50 5.18 38.48 53.81 2.53

[0288] 1.00 17.54 52.50 21.64 8.32

[0289] 2.00 45.45 30.90 1.75 21.90

[0290]

[0291] Example 37, Control Example (modification with K2CO3, with ammonia)

[0292] A 300 ml stainless steel reactor was charged with 100 ml adiponitrile, and 6 g wet Raney nickel catalyst modified with 200 g / 1 K2CO3 solution as given in Example 2 but K2CO3 was applied as modifier instead of K3PO4, and 7.48 g (0.44 mol) ammonia was added. The reaction was run for 2 hours under 20 bar hydrogen at 65 °C and the reaction was stirred at 1500 rpm. At the final conversion rate of 99.1%, the overall selectivity to ACN and HMD was 96.1% and the overall yield of ACN and HMD was 95.2%. The yield of ACN was 47.6% at this conversion, and a selectivity to ACN of 48.1%.

[0293] It can be seen that these results are much poorer than the same in e.g., Example

[0294] 16. t Conversion Selectivity (%) Yield (%) .17 13.21 2.20 97.80 0.29 12.92 .33 28.31 4.91 95.09 1.39 26.92 .50 43.44 7.71 91.09 3.35 39.57 .00 74.07 17.56 80.53 13.01 59.65 .00 99.07 48.01 48.07 47.56 47.62

[0295] Concentration(%)

[0296] 0 0 0 100 0

[0297] 0.17 0.29 12.92 86.79 0.00

[0298] 0.33 1.39 26.92 71.69 0.00

[0299] 0.50 3.35 39.57 56.56 0.52

[0300] 1.00 13.01 59.65 25.93 1.41

[0301] 2.00 47.56 47.62 0.93 3.89 Example 38, Control Example (without ammonia + is the modifier)

[0302] A 300 ml stainless steel reactor was charged with 100 ml adiponitrile, and 6 g wet Raney nickel catalyst modified with 200 g / 1 NasPCU solution as given in Example 2 but NasPCU was applied as modifier instead of K3PO4. The reaction was run 2 hours under 20 bar hydrogen at 65 °C and the reaction was stirred at 1500 rpm. At a conversion rate of 99.0%, the overall selectivity to ACN and HMD was 79.3%, i.e. the side products are over 20 %. The overall yield of ACN and HMD was 78.5%. The yield of ACN was 33.8% at this conversion, and a selectivity to ACN of 34.2%.

[0303] Example 39, Control Example (with ammonia + NasPCUis the modifier)

[0304] A 300 ml stainless steel reactor was charged with 100 ml adiponitrile, and 6 g wet Raney nickel catalyst modified with 200 g / 1 NasPCU solution as given in Example 2 but NasPCU was applied as modifier instead of K3PO4, and 7.48 g (0.44 mol) ammonia was added. The reaction was run for 2 hours under 20 bar hydrogen at 65 °C and the reaction was stirred at 1500 rpm. At a conversion rate of 99.3%, the overall selectivity to ACN and HMD was 95.0%. The overall yield of ACN and HMD was 94.3%, i.e. the side products are almost 5 %. The yield of ACN was 43.4% at this conversion, and a selectivity to ACN of 43.7%.

[0305] Example 40, Control Example, (without ammonia + KH2PO4 is the modifier)

[0306] A 300 ml stainless steel reactor was charged with 100 ml adiponitrile, and 6 g wet Raney nickel catalyst modified with 200 g / 1 KH2PO4 solution as given in Example 2 but KH2PO4 was applied as modifier instead of K3PO4. The reaction was run for 2 hours under 20 bar hydrogen at 65 °C and the reaction was stirred at 1500 rpm. At a conversion rate of 99.5%, the overall selectivity to ACN and HMD was 77.2% i.e. the side products are over 22 %. The overall yield of ACN and HMD was 76.8%. The yield of ACN was 27.4% at this conversion, and a selectivity to ACN of 27.5%.

[0307] Example 41, Control Example (with ammonia + KH2PO4 is the modifier)

[0308] A 300 ml stainless steel reactor was charged with 100 ml adiponitrile, and 6 g wet Raney nickel catalyst modified with 200 g / 1 KH2PO4 solution as given in Example 2 but KH2PO4 was applied as modifier instead of K3PO4, and 7.48 g (0.44 mol) ammonia was added. The reaction was run for 2 hours under 20 bar hydrogen at 65 °C and the reaction was stirred at 1500 rpm. At a conversion rate of 99.0%, the overall selectivity to ACN and HMD was 92.1%. The overall yield of ACN and HMD was 91.2% i.e. the side products are almost 9 %. The yield of ACN was 38.6% at this conversion, and a selectivity to ACN of 39.0%.

Claims

CLAIMS1. Modified nickel or cobalt catalyst comprising an alkali metal phosphate, hydrogen phosphate and / or pyrophosphate as modifier which is adsorbed on a nonmodified nickel or cobalt catalyst, wherein the alkali metal phosphate, hydrogen phosphate and / or the pyrophosphate is / are selected from the group consisting of M3PO4, M2HPO4 and M4P2O7, preferably M3PO4 and M4P2O7, wherein M is selected from the group of K, Rb and Cs.

2. Modified nickel or cobalt catalyst according to claim 1, wherein the modifier is selected from the group of K3PO4, K2HPO4 and K4P2O7, preferably K3PO4 and K4P2O7.

3. Modified nickel or cobalt catalyst according to claim 2, wherein the modifier is K3PO4.

4. Process for the preparation of a modified nickel or cobalt catalyst comprising an alkali metal phosphate, hydrogen phosphate and / or pyrophosphate, preferably alkali metal phosphate and / or pyrophosphate as modifier which is adsorbed on a non-modified nickel or cobalt catalyst, which comprises the following steps: a) providing a solution of an alkali metal phosphate, hydrogen phosphate and / or pyrophosphate, preferably alkali metal phosphate and / or pyrophosphate, selected from the group consisting of M3PO4, M2HPO4 and M4P2O7, preferably M3PO4 and M4P2O7, wherein M is selected from the group of K, Rb and Cs. b) slurrying the non-modified nickel or cobalt catalyst in the solution of step a), c) separating the modified nickel or cobalt catalyst obtained in step b) from the solution, d) optionally, the separated modified nickel or cobalt catalyst obtained in step c) is washed.

5. Process according to claim 4, where the solution of step a) is an aqueous solution.

6. Process according to claim 4 or 5, where the slurry of step b) is stirred for a period of 0.1-24 hours, preferably 0.5-12 hours, more preferably 0.7-1.5 hours.

7. Process according to any of claims 4 to 6, where the concentration of the alkali metal phosphate, hydrogen phosphate and / or pyrophosphate, preferably alkali metal phosphate and / or pyrophosphate in step a) is 10-900 g / 1, preferably 50-400 g / 1.

8. A process for the preparation of aminonitriles and diamines, said process comprising the hydrogenation of a dinitrile in the presence of a modified catalyst according to claims 1 to 7, optionally in the presence of ammonia.

9. Process according to claim 8, where the hydrogenation is carried out in lack of ammonia.

10. Process according to claim 8, where the hydrogenation is carried out in the presence of ammonia.

11. Process according to any of claims 8 to 10, where the dinitrile is characterized by general formula NC-R-CN, wherein R is a linear or branched alkylene or alkenylene group containing 1 to 12 carbon atoms.

12. Process according to claim 11, where the dinitrile is adiponitrile and the prepared aminonitrile is 6-aminocapronitrile (ACN) and the prepared diamine is hexamethylenediamine (HMD).

13. Process according to any of claim 12, where the adiponitrile is mixed with HMD before the start of the hydrogenation.

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