Methods for producing nitriles and phosphorus-containing catalysts for use in such methods

Abstract

A process for the hydrocyanation of an organic compound containing at least one olefinic group, the process comprising reacting the organic compound with hydrogen cyanide in the presence of a catalyst complex comprising at least one transition metal and a phosphorus-containing ligand, the phosphorus-containing ligand comprises a calixarene backbone and at least two aryl phosphite or aryl phosphoramidite groups chemically bonded to the backbone.

Description

Citation of Related Applications

[0001] This application claims the benefit of U.S. Provisional Application No. 63 / 394,306, filed on August 2, 2022, and UK Application No. 2215103.9, filed on October 13, 2022. The entire contents of these applications are incorporated herein by reference in their entirety. Technical Field

[0002] The present application relates to processes for producing nitriles and phosphorus-containing catalysts for use in such processes. Background Art

[0003] Nitriles are found in many useful compounds, including methyl cyanoacrylate, which is used in superglue, and nitrile rubber, a nitrile-containing polymer used in latex-free laboratory and medical gloves. Nitrile rubber is also widely used as an automotive and other seal because of its resistance to fuels and oils. Perhaps the best-known and commercially important nitrile is adiponitrile, a precursor for making nylon-6,6.

[0004] A well-known method for producing nitriles is by hydrocyanation of organic compounds containing one or more olefinic groups. For example, adiponitrile can be produced by a multi-step process in which 1,3-butadiene undergoes hydrocyanation to produce 3-pentenenitrile and 2-methyl-3-butenenitrile, and then 3-pentenenitrile undergoes further hydrocyanation to produce the desired adiponitrile. 2-methyl-3-butenenitrile is conveniently isomerized to produce additional 3-pentenenitrile. Catalyst complexes comprising phosphorus-containing ligands and transition metals effectively promote the hydrocyanation and isomerization reactions.

[0005] For example, Foo et al., U.S. Pat. No. 5,821,378 discloses a liquid phase method for hydrocyanating diene compounds (such as 1,3-butadiene) to produce non-conjugated acyclic nitriles and a liquid phase method for isomerizing those nitriles to 3-monoolefin linear nitriles and / or 4-monoolefin linear nitriles, wherein the reaction is carried out in the presence of zero-valent nickel and multidentate phosphite ligands. Other catalytic methods for hydrocyanating olefins and isomerizing monoolefin nitriles are described in the patents and publications cited therein. Published International Application WO99 / 06357 discloses multidentate phosphite ligands with alkyl ether substituents on the carbon of the ortho position attached to the terminal phenol group, which are used for hydrocyanating diene compounds to produce non-conjugated acyclic nitriles and liquid phase methods for isomerizing those nitriles to 3-monoolefin linear nitriles and / or 4-monoolefin linear nitriles. Other suitable hydrocyanation catalysts are disclosed in U.S. Pat. Nos. 9,040,733 and 9,040, 735.

[0006] Although the above-described catalyst systems may represent commercially viable catalysts, it is still desirable to provide even more effective, higher performing catalyst precursor compositions, catalytic compositions, and catalytic methods to achieve the full commercial potential of desired reactions. Effectiveness and / or performance may be achieved in terms of any or all of rapidity, selectivity, efficiency, or stability, depending on the reaction being performed. It is also desirable to provide improved catalyst systems and / or methods that can be optimized for such commercially important reactions, such as hydrocyanation or double bond isomerization. Summary of the invention

[0007] In accordance with the present application, it has now been discovered that catalyst complexes containing certain calixarene-based phosphorus-containing ligands and at least one transition metal are effective in catalyzing the hydrocyanation and double bond isomerization of olefinic compounds.

[0008] Thus, in one aspect, the present application provides a method for hydrocyanating an organic compound containing at least one olefinic group, the method comprising reacting the organic compound with hydrogen cyanide in the presence of a catalyst complex comprising at least one transition metal and a phosphorus-containing ligand, the phosphorus-containing ligand comprising a calixarene backbone and at least two aryl phosphite or aryl phosphoramidite groups chemically bonded to the backbone, wherein when the at least two aryl phosphite groups are chemically bonded to the backbone:

[0009] (i) The phosphorus atom of each arylphosphite group is bonded to two adjacent benzene rings of the calixarene backbone through the oxygen atom of the hydroxyl group of the calixarene, and each phosphorus atom has -OR 2 Substituents, where R 2 is a phenyl ring substituted with 1 to 5 primary alkyl groups, and all other carbon atoms are unsubstituted; or

[0010] (ii) The phosphorus atom of each arylphosphite group is bonded to a benzene ring of the calixarene backbone through the oxygen atom of the hydroxyl group of the calixarene, and the phosphorus atom has two -OR 3 Substituents, where R 3 is an optionally substituted aryl group.

[0011] In another aspect, the present application provides a method for double bond isomerization of a monoethylenically unsaturated compound, wherein the compound is contacted with a catalyst complex comprising at least one transition metal and a phosphorus-containing ligand, the phosphorus-containing ligand comprising a calixarene backbone and at least two aryl phosphite or aryl phosphoramidite groups chemically bonded to the backbone, wherein when the at least two aryl phosphite groups are chemically bonded to the backbone:

[0012] (i) The phosphorus atom of each arylphosphite group is bonded to two adjacent benzene rings of the calixarene backbone through the oxygen atom of the hydroxyl group of the calixarene, and each phosphorus atom has -OR 2 Substituents, where R 2 is a phenyl ring substituted with 1 to 5 primary alkyl groups, and all other carbon atoms are unsubstituted; or

[0013] (ii) The phosphorus atom of each arylphosphite group is bonded to a benzene ring of the calixarene backbone through the oxygen atom of the hydroxyl group of the calixarene, and the phosphorus atom has two -OR 3 Substituents, where R 3 is an optionally substituted aryl group.

[0014] In other aspects, the present application provides a phosphorus-containing ligand having one of the following structures:

[0015]

[0016] .

[0017] In yet other aspects, the present application provides a catalyst complex comprising a phosphorus-containing ligand as described herein and at least one transition metal. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 is a simplified block diagram of an integrated process for producing adiponitrile according to one embodiment of the present disclosure, the integrated process including the steps of hydrocyanating 1,3-butadiene, isomerizing 2-methyl-3-butenenitrile, and hydrocyanating 3-pentenenitrile. DETAILED DESCRIPTION

[0019] Described herein are catalytic processes for the hydrocyanation of organic compounds containing at least one olefinic group, in particular 1,3-butadiene and 3-pentenenitrile, and double bond isomerization of monoolefinically unsaturated compounds, such as 2-methyl-3-butenenitrile, in the presence of a catalyst complex containing a calixarene-based phosphorus-containing ligand and at least one transition metal. Also described herein are certain novel calixarene-based phosphorus-containing ligands and catalyst complexes comprising the novel ligand and at least one transition metal.

[0020] Phosphorus-containing ligands

[0021] In its broadest aspect, the phosphorus-containing ligand employed herein comprises a calixarene backbone and at least two aryl phosphite or aryl phosphoramidite groups chemically bonded to the backbone. The phosphorus atom of each aryl phosphite group or aryl phosphoramidite group is bonded to one benzene ring or two adjacent benzene rings of the calixarene backbone through the oxygen atom of the hydroxyl group of the calixarene, wherein when at least two aryl phosphite groups are chemically bonded to the backbone,

[0022] (i) The phosphorus atom of each arylphosphite group is bonded to two adjacent benzene rings of the calixarene backbone through the oxygen atom of the hydroxyl group of the calixarene, and each phosphorus atom has -OR 2 Substituents, where R 2 is a phenyl ring substituted with 1 to 5 primary alkyl groups, and all other carbon atoms are unsubstituted; or

[0023] (ii) The phosphorus atom of each arylphosphite group is bonded to a benzene ring of the calixarene backbone through the oxygen atom of the hydroxyl group of the calixarene, and the phosphorus atom has two -OR 3 Substituents, where R 3 is an optionally substituted aryl group. In some embodiments, the calixarene backbone comprises four benzene rings connected by methylene groups. In some embodiments, each benzene ring of the calixarene backbone is substituted with a tert-butyl group at the meta position relative to the attached methylene group.

[0024] Preferably, the calixarene backbone is a calix-[4]-arene, more preferably a calix[4]arene wherein each benzene ring is substituted with a tert-butyl group at the meta position relative to the attached methylene group.

[0025] The ligand of the present invention contains at least two aryl phosphite groups bonded to two adjacent benzene rings of the calixarene main chain, at least two aryl phosphite groups bonded to one benzene ring of the calixarene main chain, or at least two aryl phosphoramidite groups bonded to the calixarene main chain. Each of these embodiments is described in more detail below.

[0026] In one embodiment, the phosphorus-containing ligand comprises a calixarene backbone and at least two aryl phosphite groups chemically bonded to the backbone, wherein the phosphorus atom of each aryl phosphite group is bonded to two adjacent benzene rings of the calixarene backbone through the oxygen atom of the hydroxyl group of the calixarene, and each phosphorus atom has an -OR 2 Substituents, where R 2 is a phenyl ring substituted with at least one primary alkyl group. 2 Is 1 to 5 C 1 -C 4Phenyl substituted with primary alkyl groups such as methyl, ethyl, n-propyl and n-butyl, more preferably 1 to 5 methyl groups. Even more preferably, R 2 is a xylyl group. Most preferably, R 2 yes Preferably, the calixarene backbone is a calix-[4]-arene, preferably wherein each phenyl ring of the calixarene backbone is substituted with a tert-butyl group at the meta position relative to the attached methylene group.

[0027] In an alternative embodiment, the phosphorus-containing ligand comprises a calixarene backbone and at least two aryl phosphite groups chemically bonded to the backbone, wherein the phosphorus atom of each aryl phosphite group is bonded to a benzene ring of the calixarene backbone through an oxygen atom of a hydroxyl group of the calixarene, and the phosphorus atom has two -OR 3 Substituents, where R 3 is an optionally substituted aryl group. Preferably, R 3 is a phenyl ring optionally substituted by at least one alkyl group. More preferably, R 3 Is 1 to 5 C 1 -C 4 Preferably, R 3 is a xylyl group. Each R 3 can be the same or different. Optionally, the benzene rings of the calixarene backbone that do not carry an arylphosphite substituent may be substituted with one or more alkyl groups or one or more alkoxy groups. Preferred substituents are alkoxy groups, especially C 1-4 Alkoxy groups, most preferably methoxy groups. In a preferred embodiment, the benzene rings of the calixarene backbone that do not carry an arylphosphite substituent are each substituted with a methoxy group. Preferably, the calixarene backbone is a calix-[4]-arene, preferably wherein each benzene ring of the calixarene backbone is substituted with a tert-butyl group at the meta position relative to the attached methylene group.

[0028] In another alternative embodiment, the phosphorus-containing ligand comprises a calixarene backbone and at least two aryl phosphoramidite groups chemically bonded to the backbone. Preferably, the phosphorus atom of each aryl phosphoramidite group is bonded to two adjacent benzene rings of the calixarene backbone through the oxygen atom of the hydroxyl group of the calixarene. The phosphorus atom has -NHR 3 Substituents, where R 3 is an optionally substituted aryl group. Preferably, R 3 is a phenyl ring optionally substituted by at least one alkyl group. More preferably, R 3 Is 1 to 5 C 1 -C 4Preferably, R 3 is a xylyl group. Preferably, the calixarene backbone is a calix-[4]-arene, preferably wherein each benzene ring of the calixarene backbone is substituted with a tert-butyl group at the meta position relative to the attached methylene group.

[0029] Non-limiting examples of suitable phosphorus-containing ligands include the following:

[0030]

[0031] Ligand A

[0032]

[0033] Ligand B

[0034]

[0035] Ligand C

[0036] Synthesis of phosphorus-containing ligands

[0037] Calix[4]arene, calix[6]arene and calix[8]arene (having an -OH group at the 1-position on each benzene ring) and their 4-tert-butyl substituted derivatives are all commercially available materials, for example from Alfa Aesar. Alternatively, the calixarene backbone of the ligand can be prepared using synthetic procedures. For example, methods for preparing calixarene are disclosed in Monographs in Supramolecular Chemistry No. 1, Calixarenes, 1989.

[0038] Suitable arylphosphite-substituted calixarene for use in the methods described herein can be prepared by reacting a suitable calixarene precursor with a compound of formula (R 1 O) 2 The chlorophosphite of PC1 or the formula R 1 OPC1 2 The dichlorophosphite is prepared by reaction, wherein R 1 is an aryl substituent. As used herein, the term "aryl" refers to an aromatic carbocyclic group having a single ring (e.g., phenyl), multiple rings (e.g., biphenyl), or multiple condensed rings of which at least one is aromatic (e.g., 1,2,3,4-tetrahydronaphthyl, naphthyl, anthracenyl, or phenanthrenyl), all of which are optionally substituted. In an embodiment, R 1 Contains a phenyl group substituted by one or more alkyl groups having 1 to 4 carbon atoms. Preferably, the alkyl group is a primary alkyl group, especially a methyl group. Most preferably, R 1 It is a xylyl group.

[0039] The method for producing the chlorophosphite or dichlorophosphite is not critical, as many available methods are known in the art. For example, each can be produced by PC1 3 With aromatic alcohol, R 1 OH is reacted in the presence of a suitable organic base to first prepare a dichlorophosphite, which is then (if necessary) further reacted with an aromatic alcohol to prepare the desired chlorophosphite. The selective synthesis of suitable (di)chlorophosphites is disclosed in, for example, PCT publications WO 2004 / 050588 and EP 2,243,763B1.

[0040] The resulting (di)chlorophosphite is then contacted with a calixarene precursor and a base (preferably an organic tertiary amine containing one or more basic nitrogen atoms) under conditions that promote the reaction between the (di)chlorophosphite and the calixarene to produce the desired ligand. The contact is conveniently carried out by at least one contact method selected from the group consisting of: (i) feeding the calixarene precursor to a mixture of the (di)chlorophosphite and the organic tertiary amine, and (ii) feeding the calixarene precursor and the organic tertiary amine to the (di)chlorophosphite alone or as a mixture. In embodiments, the feed is controlled so that during all stages of contacting, the ratio of the number of moles of (di)chlorophosphite in the reaction mixture divided by the number of moles of calixarene precursor fed to the reaction mixture is at least 2.0, such as 2.1 to 2.7, and during all stages of contacting, the ratio of the number of moles of basic nitrogen atoms from the organic tertiary amine fed to the reaction mixture divided by the number of moles of (di)chlorophosphite in the reaction mixture is at least 1.0, such as 1.0 to 1.5. Typically, the contacting is carried out at a temperature of about 10°C to about 110°C, such as about 20°C to about 110°C, such as about 30°C to about 110°C, such as about 40°C to about 110°C, such as about 50°C to about 110°C, such as about 60°C to about 110°C.

[0041] Examples of suitable organic tertiary amines containing a single basic nitrogen atom may be (R')(R'')(R''')N compounds, wherein R', R'' and R''' are independently selected from C 1 To C 10 Alkyl groups and C 6 To C 10 The present invention can be a group of tertiary aromatic amines, or can be an aromatic tertiary amine compound (e.g., pyridine), or can be a combination of organic tertiary amines containing a single basic nitrogen atom. An example of a suitable amine includes a trialkylamine having a single selected alkyl group and having 1 to 10 carbon atoms, such as triethylamine. Other examples include organic tertiary amines containing multiple basic nitrogen atoms, the organic tertiary amine having a nitrogen atom without an N--H bond; for example, N,N,N',N'-tetramethylethylenediamine.

[0042] In some embodiments, the reaction mixture may include at least one hydrocarbon solvent. For example, the calixarene precursor may be fed to the reaction zone containing the (di)chlorophosphite in the form of a solution of the calixarene precursor in a hydrocarbon solvent. In some embodiments, the hydrocarbon solvent may be selected from the group consisting of: a linear acyclic C 5 To C 18 Aliphatic hydrocarbons, branched acyclic C 5 To C 18 Aliphatic hydrocarbons, unsubstituted cyclic C 5 To C 18 Aliphatic hydrocarbons, substituted cyclic C 5 To C 18 Aliphatic hydrocarbons, unsubstituted C 6 To C 10 Aromatic hydrocarbons and C 7 To C 18 Substituted aromatic hydrocarbons. The hydrocarbon solvent may be selected from hydrocarbons having a boiling point of 70°C to 145°C at atmospheric pressure. Examples of suitable aromatic hydrocarbon solvents include C 1 -C 5 Substituted benzenes such as xylenes and toluene.

[0043] Contact method (i) and contact method (ii) can be carried out in a semi-batch, continuous flow or a combination of semi-batch and continuous flow modes. For example, the calixarene precursor can be continuously or discontinuously fed into a stirred vessel comprising a (di)chlorophosphite and an organic tertiary amine. In addition, the calixarene precursor can be continuously or discontinuously fed into a tubular reactor comprising a continuous flow of a mixture of a (di)chlorophosphite and an organic tertiary amine.

[0044] Alternatively, the appropriate phosphite or phosphoramidate substituted ligand may be produced by reacting an appropriate calixarene precursor with phosphorus trichloride to produce the chlorophosphite or dichlorophosphite of the calixarene and then reacting the resulting (di)chlorophosphite with an aromatic alcohol or amine.

[0045] Thus, ligands A and B (as shown above) can be produced by charging a calixarene backbone into a suitable reactor under an inert atmosphere, particularly an argon atmosphere. An excess of phosphorus trichloride is added to the reactor, and the material is slowly heated to reflux. After all HCl has been removed from the reactor, the material is evacuated to produce a crude chlorophosphite, which is subsequently distilled. To a mixture of the purified chlorophosphite in toluene are added 2 equivalents of 2,4-xylenol or 2,4-xylenidine to provide a diphosphite or bisphosphoramidate ligand A or B, respectively. The resulting ligand can be purified by recrystallization before use.

[0046] The synthesis of ligand C can be completed by a 3-step process. Under argon protection, o-cresol (2 equivalents) is charged into a suitable reactor. Phosphorus trichloride (1 equivalent) is added to the mixture. The material is then heated to reflux and maintained therein until the release of HCl is observed to stop. The crude mixture is then distilled to provide a purified chlorophosphite. In a separate container, p-tert-butylcalixarene tetraol is dissolved in acetone and 2 equivalents of methyl iodide are added together with lithium carbonate. The mixture is refluxed for 4 hours. The material is then filtered through a diatomaceous earth plug and used without further purification. In the final step, a solution of the chlorophosphite is prepared in diethyl ether, to which triethylamine and the dimethylcalixarene diol produced in the previous step are added. The mixture is heated to reflux for 4 hours. The mixture is then cooled, and the solid is separated by filtration. The product can be recrystallized from valeronitrile.

[0047] Catalyst complex

[0048] The multidentate phosphite ligand disclosed herein can be used to form a catalyst complex (chelate) in combination with a transition metal. The transition metal used in the catalyst complex can be any transition metal capable of carrying out the desired catalytic conversion, and can additionally contain unstable ligands that are displaced during the catalytic reaction or that play an active role in the catalytic conversion. Any transition metal can be considered in this respect. Preferred metals are those comprising the VIIIth Group of the periodic table. Preferred metals for hydrocyanation and / or isomerization are nickel, cobalt and palladium, wherein nickel is particularly preferably used for olefin hydrocyanation.

[0049] Nickel complexes of each phosphorus-containing ligand described herein are disclosed.

[0050] Nickel compounds can be prepared or generated according to techniques well known in the art, such as described in, for example, U.S. Pat. Nos. 3,496,217, 3,631,191, 3,846,461, 3,847,959, and 3,903,120, which are incorporated herein by reference. Zero-valent nickel complexes containing ligands that can be displaced by organophosphorus ligands can be used as nickel sources. Two such zero-valent nickel complexes are Ni(COD) 2 (COD is 1,5-cyclooctadiene) and Ni{P(OoC 6 H 4 CH 3 ) 3} 2 (C 2 H 4 ), both of which are known in the art. Alternatively, a divalent nickel compound may be combined with a reducing agent to serve as a nickel source in the reaction. Suitable divalent nickel compounds include those of the formula NiY 2A compound wherein Y is a halide, a carboxylate or an acetylacetonate. Suitable reducing agents include metal borohydrides, metal aluminum hydrides, metal alkyls, Zn, Fe, Al, Na or H 2 .

[0051] U.S. Patent No. 10,537,885 describes a method for preparing zero-valent nickel having high activity for complexing with phosphorus-containing ligands and comprising calcining a first nickel(II)-containing particle in an atmosphere comprising an oxidizing component and at a temperature generally between 350°C and 600°C for a time sufficient to remove volatile components from the first nickel(II)-containing particle and produce a second nickel(II)-containing particle. The second nickel(II)-containing particle is then heated in a reducing atmosphere while rotating or tumbling the second nickel(II)-containing particle in a rotary processor at 275°C to 360°C for a time sufficient to produce a free-flowing particulate nickel metal (Ni(0)) product, wherein the reducing atmosphere does not contain added water or steam not generated by the reduction, and wherein a H2O of about 1.9 to 2.5 is employed during the reducing step. 2 / Ni molar ratio.

[0052] Elemental nickel, preferably nickel powder, is also a suitable source of zero-valent nickel when combined with a halogenation catalyst as described in US Pat. No. 3,903,120.

[0053] In some embodiments, elemental nickel may be present in an amount having at least about 1 m 2 The nickel particulate form may have at least 10% of the crystallites in the nickel form having a diameter (C10) of less than about 10 nm, and / or an average crystallite size of at least about 100 nm per gram of nickel. 15 The ratio of BETSSA to C50 in the form of nickel particles may be at least about 0.1×10 9 m / gm and preferably at least about 0.4×10 9 Examples of such small particle forms of nickel and methods of making them can be found in US Pat. No. 9,050,591, the entire contents of which are incorporated herein by reference.

[0054] Depending on the desired reaction to be performed, the catalyst composition may also include one or more Lewis acid promoters, which affect the activity and selectivity of the catalyst system. The promoter may be an inorganic or organometallic compound, wherein at least one element of the inorganic or organometallic compound is selected from scandium, titanium, vanadium, chromium, manganese, iron, cobalt, copper, zinc, boron, aluminum, yttrium, zirconium, niobium, molybdenum, cadmium, rhenium and tin. Examples include ZnBr 2 、ZnI 2 、ZnCl 2 、ZnSO 4 , CuCl2 、CuCl、Cu(O 3 SCF 3 ) 2 、CoCl 2 、CoI 2 ,FeI 2 、FeCl 3 、FeCl 2 、FeCl 2 (THF) 2 、TiCl 4 (THF) 2 、TiCl 4 、TiCl 3 、ClTi(OiPr) 3 、MnCl 2 ScCl 3 、AlCl 3 , (C 8 H 17 )AlCl 2 , (C 8 H 17 ) 2 AlCl, (iso-C 4 H 9 ) 2 AlCl、Ph 2 AlCl、PhAlCl 2 、ReCl 5 、ZrCl 4 、NbCl 5 、VCl 3 CrCl 2 、MoCl 5 , YCl 3 , CdCl 2 、LaCl 3 、Er(O 3 SCF 3 ) 3 , Yb(O 2 CCF 3 ) 3 、SmCl 3 , B(C 6 H 5 ) 3 、TaCl 5 Suitable promoters are further described in U.S. Pat. Nos. 3,496,217, 3,496,218 and 4,774,353. These include metal salts such as ZnCl 2 、CoI 2 and SnCl 2 ) and organometallic compounds (such as RAlCl2 , R 3 SnO 3 SCF 3 and R 3 B, wherein R is an alkyl group or an aryl group). U.S. Patent No. 4,874,884 describes how to select a synergistic combination of promoters to improve the catalytic activity of the catalyst system. Preferred promoters include CdCl 2 、FeCl 2 、ZnCl 2 , B(C 6 H 5 ) 3 and (C 6 H 5 ) 3 SnX, where X is CF 3 SO 3 , CH 3 C 6 H 5 SO 3 or (C 6 H 5 ) 3 The molar ratio of promoter to nickel present in the reaction may be in the range of about 1:16 to about 50:1.

[0055] Catalytic method using a catalyst complex

[0056] According to the present application, the above-mentioned catalyst complex can be used for hydrocyanation of compounds containing at least one olefinic group to produce nitrile and for double bond isomerization of monoolefinic unsaturated compounds (especially nitrile). The preferred use of the above-mentioned catalyst complex in which the transition metal is nickel is for catalytic hydrocyanation of 1,3-butadiene to produce 3-pentenenitrile, which is then converted into adiponitrile. In an embodiment, in the first reaction zone, 1,3-butadiene reacts with hydrogen cyanide in the presence of a first catalyst to produce pentenenitrile comprising 3-pentenenitrile and 2-methyl-3-butenenitrile. In an optional second reaction zone, 2-methyl-3-butenenitrile recovered from the first reaction zone is isomerized to 3-pentenenitrile on a second catalyst. In the third reaction zone, 3-pentenenitrile recovered from the first reaction zone and the second reaction zone reacts with hydrogen cyanide in the presence of a third catalyst and a Lewis acid to produce adiponitrile. One, two or all of the first catalyst, the second catalyst and the third catalyst can be the above-mentioned catalyst complex.

[0057] For example, 3-pentenenitrile (3PN) can be formed from 1,3-butadiene through a series of reactions as shown in Equation 1 and Equation 2 below.

[0058]

[0059] According to the abbreviations used herein, BD is 1,3-butadiene, 2PN is 2-pentenenitrile, 3PN is 3-pentenenitrile, 4PN is 4-pentenenitrile, 2M2BN is 2-methyl-2-butenenitrile, 2M3BN is 2-methyl-3-butenenitrile, MGN is 2-methylglutaronitrile, and ADN is adiponitrile.

[0060] In the presence of transition metal complexes containing various phosphorus-containing ligands, such as the catalyst complexes described herein, dinitriles such as ADN, MGN, and ethylsuccinonitrile (ESN) can be formed by the hydrocyanation of 3PN and 2M3BN, as shown below in Equations 3 and 4. Equation 4 also shows that 2M2BN can be formed when 2M3BN is undesirably isomerized in the presence of a Lewis acid promoter, which can be carried away from the pentenenitrile hydrocyanation reaction zone.

[0061]

[0062] According to one aspect of the present disclosure, 3-pentenenitrile is prepared in a method comprising two steps. In the first step, 1,3-butadiene is reacted with hydrogen cyanide in the presence of a first catalyst complex comprising a transition metal (such as zero-valent nickel) and a first phosphorus-containing ligand in a first reaction zone to produce a reactor effluent comprising 3-pentenenitrile (3PN) and 2-methyl-3-butenenitrile (2M3BN). In the second step, at least a portion of the 2M3BN prepared in the first step is isomerized in the presence of a second catalyst complex comprising a transition metal (such as zero-valent nickel) and a second phosphorus-containing ligand in a second reaction zone to prepare a reaction product comprising 3PN. The first catalyst complex may be the same as or different from the second catalyst complex and may be a catalyst complex as described herein. Typically, the reactions in the first reaction zone and the second reaction zone are carried out in the absence of a Lewis acid promoter.

[0063] The effluent stream containing 3PN can be recovered from the second reaction zone. In addition, 3PN is usually also recovered from the reaction product of the first reaction zone, such as by distillation. The recovered 3PN can be contacted with HCN in the presence of a third catalyst complex comprising a transition metal (such as zero-valent nickel) and a third phosphorus-containing ligand in a third reaction zone in a third reaction step. The third catalyst complex can be the same or different from the first catalyst complex and / or the second catalyst complex, and can be a catalyst complex as described herein. The reaction in the third reaction zone is carried out in the presence of a Lewis acid promoter.

[0064] In addition to 3-pentenenitrile (3PN) and 2-methyl-3-butenenitrile (2M3BN), the reaction products from the first reaction zone also contain dinitriles. These dinitriles include adiponitrile (ADN), which can be formed by the reaction of 3-pentenenitrile (3PN) with HCN, and methylglutaronitrile (MGN), which can be formed by the reaction of 2-methyl-3-butenenitrile (2M3BN) with HCN. The formation of MGN in the first reaction zone is detrimental because 2M3BN is converted before it can be recovered and isomerized to 3PN. In the process of recovering 3PN and reacting it with HCN to form ADN, the production of one mole of MGN in the first reaction zone results in the loss of two moles of HCN and one mole of BD, which could otherwise be converted to ADN. Therefore, based on the number of moles of HCN and BD reacted, the production of unwanted MGN in the first reaction zone results in a reduction in the yield of unwanted ADN.

[0065] Conversion of 1,3-butadiene to 3-pentenenitrile

[0066] The 1,3-butadiene feedstock of the first reaction zone may contain at least 98 wt%, preferably at least 99 wt%, and more preferably at least 99.5 wt% of 1,3-butadiene based on the total weight of the feedstock. In one embodiment, the feedstock contains 99.5 wt% to 99.9 wt% of 1,3-butadiene based on the total weight of the feedstock. The balance of the feedstock may contain residual levels of impurities typically found in commercial BD feedstocks, such as butane, butene, 1,2-butadiene, and acetylene (such as propyne). Typically, the BD-containing feed contains less than a total of 100 ppm of acetylene. The BD feedstock may also contain tert-butylcatechol (TBC), such as 4-tert-butylcatechol. Before 1,3-butadiene is charged to the first reaction step, a portion of the TBC present in the feedstock may be optionally removed.

[0067] The HCN feed to the first reaction zone and the third reaction zone can be a product of the Andrussow process, which is dried to less than about 250 ppm of water, such as less than 125 ppm of water, such as less than 80 ppm of water by distillation before entering the olefin hydrocyanation reaction zone. However, the HCN feed usually contains at least some water. Very dry HCN is unstable, and therefore, it may not be desirable to provide completely anhydrous HCN. Therefore, the HCN feed can contain at least 10 ppm, such as at least 25 ppm, such as at least 50 ppm of water. The HCN feed is preferably substantially free of carbon monoxide, oxygen and ammonia. This HCN can be introduced into the first reaction zone and the third reaction zone as a vapor, a liquid or a mixture thereof; see, for example, European Patent Publication No. 1 344770. As an alternative, cyanohydrin can be used as a source of HCN; see, for example, U.S. Patent No. 3,655,723.

[0068] The total feed molar ratio of BD to HCN in the first reaction zone can be in the range of about 1:1 to about 100:1, for example, in the range of about 1:1 to about 2:1. Excess BD in the first reaction zone can reduce the formation of dinitrile during the BD hydrocyanation reaction. The feed molar ratio of HCN to catalyst in the first reaction zone can be in the range of about 5:1 to about 100,000:1, for example, in the range of about 100:1 to about 5,000:1.

[0069] The reaction conditions employed in the first reaction zone may include a temperature in the range of about -25°C to about 200°C, such as a temperature in the range of about 0°C to about 150°C. Typically, the reaction pressure should be sufficient to maintain BD and HCN in contact with the catalyst dissolved in the liquid reaction mixture, such pressure being at least partially a function of the amount of unreacted BD present in the reaction mixture. Although the disclosed process is not limited by an upper pressure limit for the first reaction step, for practical purposes, the pressure is typically in the range of about 15 psia to about 300 psia (about 1.03 bar to about 20.7 bar).

[0070] During the first reaction step, the non-oxidizing and anhydrous environment prevents oxidative deactivation of the catalyst. Therefore, a dry inert atmosphere (e.g., nitrogen) is typically used in the first reaction zone, although air can be used at the expense of losing a portion of the catalyst through oxidation and hydrolysis.

[0071] In the first reaction step, the HCN feed, the BD-containing feed, and the catalyst composition may be contacted in any suitable reactor or reactors known to those skilled in the art. Examples include a continuous stirred tank reactor, a loop bubble column reactor, a gas recycle reactor, a bubble column reactor, a tubular reactor, or a combination thereof, optionally with a means for removing at least a portion of the heat of reaction.

[0072] The residence time in the first reaction zone is usually determined by the expectation of obtaining a certain degree of conversion of BD, HCN or their combination.Usually, the residence time will be in the scope of about 0.1 hour to about 15 hours, for example, in the scope of about 1 hour to about 10 hours.The HCN conversion rate can be, for example, greater than 99%.Usually, the BD conversion rate in the first reaction zone can be less than 99%, for example, between 80% and 95% in total, for example, 90% in total.The staged HCN in the first reaction zone can be used to add.

[0073] Separation of the product from the first reaction zone

[0074] The reaction of 1,3-butadiene and hydrogen cyanide in the first reaction zone in the presence of a first catalyst produces a first reaction effluent comprising 3-pentenenitrile, 2-methyl-3-butenenitrile, unreacted 1,3-butadiene and the first catalyst. These components of the reaction effluent can be at least partially separated by one or more distillation steps. In particular, these distillation steps can be carried out in one or more distillation towers to provide: 1) at least one 1,3-butadiene-rich stream; 2) a 2-methyl-3-butenenitrile-rich stream; 3) a 3-pentenenitrile-rich stream; and 4) a first catalyst-rich stream. These streams are rich in specific components because they have higher concentrations of these components than the effluent from the first reaction zone. In an embodiment, the 2-methyl-3-butenenitrile-rich stream and the 3-pentenenitrile-rich stream may each contain a total of less than 500 parts per million parts by weight of phosphorus-containing ligands, such as less than 350 parts per million parts by weight of phosphorus-containing ligands, such as less than 200 parts per million parts by weight of phosphorus-containing ligands.

[0075] In an embodiment, at least partial separation of 3-pentenenitrile and 2-methyl-3-butenenitrile in the reaction effluent from the first reaction zone can be achieved by a multi-stage distillation process. For example, such a method may include a first distillation column device, which includes a feed inlet; an upper withdrawal outlet; and a bottom withdrawal outlet. The reaction effluent containing 3PN, 2M3BN and at least one catalyst including a phosphorus-containing ligand can be supplied to the feed stage of the first distillation column through the feed inlet. The distillation column may include a stripping section, a rectifying section, or both. There may be at least one separation stage between the feed inlet and the upper withdrawal outlet. A pentenenitrile-rich stream containing 3-pentenenitrile and 2-methyl-3-butenenitrile can be taken out from the upper withdrawal outlet. This stream is depleted of at least one phosphorus-containing ligand relative to the phosphorus-containing ligand stream fed to the distillation column. The stream depleted in pentenenitrile can be taken out from the bottom withdrawal outlet. Relative to the phosphorus-containing ligand stream fed to the distillation column, this stream depleted in pentenenitrile is rich in phosphorus-containing ligands. The first distillation column may be operated such that the pentenenitrile-depleted stream comprises at least 5 wt% pentenenitrile, including the sum of 3-pentenenitrile and 2-methyl-3-butenenitrile.

[0076] The pentenenitrile-rich stream comprising 3-pentenenitrile and 2-methyl-3-butenenitrile can be distilled in a second distillation column to obtain a 2-methyl-3-butenenitrile-rich stream as an overhead product and a 2-methyl-3-butenenitrile-depleted stream (i.e., a 3-pentenenitrile-rich stream) as a bottom product. The 3-pentenenitrile-rich bottom stream can be recycled to the first reaction zone, while the 2-methyl-3-butenenitrile-rich overhead product can be fed to the second reaction zone for isomerization to produce additional 3-pentenenitrile.

[0077] The first catalyst-rich stream separated from the first reaction zone effluent is at least partially recycled to the first reaction zone, and in some cases to the second reaction zone. However, since this stream contains catalyst degradation products and reaction byproducts and may be poor in nickel, a portion of the first catalyst-rich stream is typically taken out and fed to the first catalyst purification system. In an embodiment, at least 80%, preferably at least 90%, such as 93% to 96%, at least 99%, at least 99.9%, and substantially all of the first catalyst is recycled, and the remainder is fed to the purification system. Typically, the purification system includes one or more liquid / liquid extraction zones, wherein the first catalyst-rich stream is contacted with a non-polar solvent (such as cyclohexane or other cyclic or linear alkanes) and a polar solvent (such as adiponitrile) that is immiscible with the non-polar solvent (preferably in countercurrent flow). Typically, the temperature in the extraction zone that promotes phase separation and catalyst extraction can be from 25°C to 135°C, such as 25°C to 90°C, such as 50°C to 75°C. In the extraction zone, a non-polar phase comprising the non-polar solvent and the first catalyst and a polar phase (eg, raffinate) comprising the polar solvent and, for example, reaction byproducts and catalyst degradation products are formed.

[0078] The non-polar phase is recovered from the extraction zone and then fed to a separation system, conveniently one or more distillation columns, wherein the purified first catalyst is separated from the non-polar solvent and then returned to the first reaction zone or the second reaction zone, optionally after additional nickel is added to the catalyst. The non-polar solvent can then be recycled to the liquid / liquid extraction zone. Similarly, the raffinate phase is recovered separately from the extraction zone and then fed to another separation system, conveniently one or more distillation columns, wherein reaction by-products and catalyst degradation products are separated from the polar solvent for further processing and / or disposal. The polar solvent can then be recycled to the liquid / liquid extraction zone.

[0079] Isomerization of 2-methyl-3-butenenitrile

[0080] A stream rich in 2-methyl-3-butenenitrile (2M3BN) separated from the first reaction zone effluent is fed to a second reaction zone, wherein 2M3BN is isomerized in the presence of a second catalyst complex to produce a reaction product comprising 3PN. Typically, the feed to the second reaction zone comprises at least 30% by weight of 2M3BN and less than 70% by weight of pentenenitrile different from 2M3BN. The second catalyst complex typically comprises a transition metal (such as zero-valent nickel) and a ligand, and may be the same or different from the first catalyst complex. If a monodentate phosphorus-containing ligand is used for the second catalyst complex, the molar ratio of the monodentate ligand to zero-valent nickel in the catalyst for isomerization reaction may be from about 1:1 to about 50:1, for example, from about 1:1 to about 30:1. When a bidentate ligand is used, the molar ratio of the bidentate ligand to zero-valent nickel in the catalyst for isomerization reaction may be from 1:1 to 10:1, for example, from 1:1 to 5:1.

[0081] In order to promote the isomerization of 2M3BN to produce 3PN, the reaction temperature in the second reaction zone can be maintained in the range of about 0°C to about 200°C, for example, in the range of about 50°C to about 165°C, and the pressure is generally in the range of about 15 psia to about 300 psia (about 1.03 bar to about 20.7 bar). The feed mole ratio of 2M3BN to catalyst for the isomerization reaction step is generally greater than 1:1, generally in the range of about 5:1 to 20,000:1, for example, about 100:1 to about 5,000:1. Suitable reactors for the isomerization reaction include continuous stirred tank reactors, loop bubble column reactors, gas circulation reactors, bubble column reactors, tubular reactors, or combinations thereof, optionally with a device for removing at least a portion of the heat of reaction. The residence time of the isomerization reaction in the second reaction zone can be about 0.1 hours to about 15 hours, for example, about 1 hour to about 10 hours.

[0082] Separation of the product from the second reaction zone

[0083] The effluent from the second reaction zone mainly comprises 3-pentenenitrile, residual 2-methyl-3-butenenitrile and the second catalyst. These components can be separated at least in part by one or more distillation steps to provide: 1) a second stream rich in 2-methyl-3-butenenitrile; 2) a second stream rich in 3-pentenenitrile; and 3) a second stream rich in catalyst. The second stream rich in 2-methyl-3-butenenitrile and the second stream rich in 3-pentenenitrile can each contain a total of less than 500 parts per million parts by weight of phosphorus-containing ligands. For example, the second stream rich in 3-pentenenitrile can contain less than 300ppm, for example, less than 100ppm of phosphorus-containing ligands.

[0084] The second 3-pentenenitrile-rich stream may contain a small amount of 2-methyl-3-butenenitrile, which may be separated from 3-pentenenitrile in one or more distillation columns, wherein 2-methyl-3-butenenitrile is recovered as an overhead product and 3-pentenenitrile is recovered as a bottoms product. For example, the first 3-pentenenitrile-rich stream and the second 3-pentenenitrile-rich stream may be combined and distilled in a single or shared distillation column, or these streams may be distilled in separate distillation columns. The 2-methyl-3-butenenitrile recovered from this distillation may be passed as a feed to the second reaction zone, and the 3-pentenenitrile recovered from this distillation may be passed as a feed to the third reaction zone.

[0085] The second 3-pentenenitrile-rich stream may further comprise (Z)-2-methyl-2-butenenitrile and may be distilled to obtain as an overhead product a (Z)-2-methyl-3-butenenitrile-rich stream comprising 2-methyl-3-butenenitrile and (Z)-2-methyl-2-butenenitrile and other low boilers, and as a bottom product a (Z)-2-methyl-2-butenenitrile-depleted stream comprising 3-pentenenitrile, 2-methyl-3-butenenitrile and some (Z)-2-methyl-2-butenenitrile depending on the distillation conditions. 3-Pentenenitrile and 2-methyl-3-butenenitrile may be recovered separately from the (Z)-2-methyl-2-butenenitrile-depleted stream to be passed to the third reaction zone and recycled to the second reaction zone, respectively.

[0086] At least a portion of the second stream rich in 3-pentenenitrile can be used to prepare a catalyst solution. In particular, at least a portion of the second stream rich in 3-pentenenitrile can be passed into a catalyst reaction zone, wherein the nickel metal reacts with the phosphorus-containing ligand to produce a catalyst solution comprising the catalyst and pentenenitrile. A portion of this catalyst solution can be passed into the second reaction zone. When the first catalyst and the second catalyst comprise the same phosphorus-containing ligand, a portion of the catalyst can be passed into the first reaction zone.

[0087] The second catalyst-rich stream recovered from the reaction effluent of the second reaction zone can be purified by liquid / liquid extraction, as discussed above for the first catalyst-rich stream separated from the effluent of the first reaction zone. In fact, when the first catalyst complex and the second catalyst complex are the same, a single liquid / liquid extraction system can be used to purify both catalysts.

[0088] Hydrocyanation of 3-pentenenitrile to adiponitrile

[0089] The 3-pentenenitrile produced in the first reaction zone and the second reaction zone is passed to a third reaction zone wherein the 3PN is reacted with additional hydrogen cyanide in the presence of a third phosphorus-containing catalyst complex to produce adiponitrile.

[0090] The 3-pentenenitrile feed to the third reaction zone is obtained from the above-described distillation step and may typically comprise at least 95 wt % 3PN, less than 5 wt % pentenenitrile other than 3PN, and less than 0.1 wt % of the first phosphorus-containing ligand. The 3PN feed may comprise less than 5000 parts per million (ppm), such as less than 2000 parts per million (ppm), such as less than 1000 parts per million (ppm), such as less than 600 parts per million (ppm) of C 9 Mononitrile.

[0091] The HCN feed entering the third reaction zone can be a product of an Andrussow process that has been dried by distillation to less than about 250 ppm of water, such as less than 125 ppm of water, such as less than 80 ppm of water. However, the HCN feed typically contains at least some water because very dry HCN is unstable. Therefore, the HCN feed can contain at least 10 ppm, such as at least 25 ppm, such as at least 50 ppm of water. The HCN feed entering the third reaction zone is preferably substantially free of carbon monoxide, oxygen, and ammonia. As an alternative, cyanohydrin can be used as a source of HCN; see, for example, U.S. Patent No. 3,655,723.

[0092] The third phosphorus-containing catalyst complex usually comprises a transition metal (such as zero-valent nickel) and a monodentate or bidentate phosphorus-containing ligand, which may be the same or different from the ligand used in the first catalyst complex or the second catalyst complex. However, the third phosphorus-containing catalyst complex usually comprises one or more promoters to improve the production of dinitrile. As known in the art, promoters affect catalyst activity and selectivity to required ADN. The promoters used include salts of metals with atomic numbers of 13, 21-32, 39-50 and 57-80, such as zinc, and formula BR' 3 Compounds wherein R' is an alkyl group or an aryl group of up to 18 carbon atoms, such as triphenylborane. The anion of such metal salts may include halides, such as chlorides, sulfates, phosphates, and lower aliphatic carboxylates. Useful promoters are generally referred to in the art as Lewis acids. In one embodiment, when the Lewis acid promoter is ZnCl 2 When the molar ratio of the promoter to the nickel in the third catalyst complex can be 1:20 to 50:1, such as 0.2:1 to 2:1.

[0093] The conditions used in the third reaction zone may generally include a temperature in the range of about 0°C to about 150°C, such as a temperature in the range of about 25°C to about 80°C. Typically, the reaction pressure should be sufficient to keep the HCN in contact with the catalyst dissolved in the liquid reaction mixture. This pressure is at least in part a function of the amount of unreacted HCN present in the reaction mixture. Although the upper pressure limit of this reaction step is not limited to any particular pressure, for practical purposes, the pressure is generally in the range of about 15 psia to about 300 psia (about 1.03 bar to about 20.7 bar). The total feed molar ratio of 3PN to HCN in the third reaction zone may be 1:1 to 100:1, such as 1:1 to about 5:1, and the molar ratio of HCN to the catalyst may be 10:1 to 5000:1, such as 100:1 to 3000:1, such as 300:1 to 2000:1. The phosphorus-containing ligand used in the reaction of 3PN with HCN is preferably a bidentate ligand. The mol ratio of bidentate ligand and nickel in the catalyst for 3PN hydrocyanation step can be 1: 1 to 10: 1, for example 1: 1 to 5: 1, for example 1: 1 to 3: 1. The residence time in the third reaction zone is determined by the expectation of obtaining a certain degree of transformation efficiency of pentenenitriles, HCN or their combination. Except the residence time, catalyst concentration and reaction temperature will also affect the conversion of reactant to product. Usually, the residence time will be in the scope of about 0.1 hour to about 30 hours, for example, in the scope of about 1 hour to about 20 hours. The HCN transformation efficiency can be greater than 99%.

[0094] Suitable reactors for the third reaction zone include continuous stirred tank reactors, loop bubble column reactors, gas recycle reactors, bubble column reactors, tubular reactors or combinations thereof, optionally with means for removing at least a portion of the heat of reaction.

[0095] Separation of the product from the third reaction zone

[0096] The reaction product mixture from the third reaction zone is mainly composed of dinitriles, especially the desired adiponitrile (ADN) and some 2-methylglutaronitrile (MGN), pentenenitrile (such as 3PN, 2PN and (E)-2M2BN), catalyst, catalyst degradation products and promoter. These components can be separated by any method known in the art, but are usually treated by a combination of distillation and liquid / liquid extraction steps. For example, one or more distillation stages can be included between the third reaction zone and the downstream liquid extraction zone to remove lower boiling components from the product mixture, including unreacted 3-pentenenitrile. The remaining product mixture is then fed to the liquid / liquid extraction zone, where the mixture is contacted with an extraction solvent. In the extraction zone, an extraction phase comprising the extraction solvent and the third catalyst and a raffinate phase comprising adiponitrile, catalyst degradation products and promoter are formed.

[0097] The extract phase is passed into a distillation column, in which the extraction solvent is separated from the catalyst for recycling back to the extraction zone. A catalyst stream is taken out from the distillation column and recycled back to the third reaction zone. The raffinate phase can be distilled in one or more distillation steps to separate adiponitrile (ADN) and methylglutaronitrile (MGN) from compounds with a boiling point higher than adiponitrile (ADN) and compounds with a boiling point lower than methylglutaronitrile (MGN) to obtain a first refined dinitrile stream. The first refined dinitrile stream can be further distilled to remove methylglutaronitrile (MGN) from the first refined dinitrile stream to obtain a second refined dinitrile stream rich in adiponitrile. At least a portion of the second refined dinitrile stream is recycled to the liquid / liquid extraction step as a dinitrile recycle stream.

[0098] Now refer to Figure 1 An embodiment of a representative process for preparing adiponitrile from 1,3-butadiene is described. As shown in the figure, in the process shown, 1,3-butadiene feed is supplied to the first reaction zone Z via pipeline 100. 1 , which also receives a supply of hydrogen cyanide via line 120 and a supply of a first phosphorus-containing catalyst complex via line 140. 1 In the embodiment of the present invention, the conditions are controlled so that 1,3-butadiene reacts with hydrogen cyanide to produce a reaction product comprising essentially 3-pentenenitrile (3PN) and 2-methyl-3-butenenitrile (2M3BN). The reaction effluent stream is removed from the first reaction zone Z via line 122. 1 The catalyst stream 140 and the product stream 200 comprising 2-methyl-3-butenenitrile (2M3BN) are removed from the reaction product and introduced into the separation section 125 to obtain, among other things, a concentrated catalyst stream 140 and a product stream 200 comprising 2-methyl-3-butenenitrile (2M3BN). The separation section 125 may include one or more distillation columns. Unreacted hydrogen cyanide and 1,3-butadiene may also be separated from the reaction products and the catalyst in the separation section 125. Unreacted 1,3-butadiene may be separated from the reaction product and the catalyst by Figure 1 The pipeline not shown in the figure is recycled to the first reaction zone Z 1 The stream containing 3-pentenenitrile (3PN) can also be processed by Figure 1 A pipeline not shown in FIG. 1 is taken out from the separation section 125 .

[0099] A portion of the catalyst separated from the reaction products in separation section 125 is recycled to the first reaction zone Z via line 140. 1 , while additional catalyst is partially removed and fed to liquid / liquid extraction zone 150 via line 126 to at least partially purify or regenerate the catalyst. A non-polar solvent, such as an alkane, is fed to liquid / liquid extraction zone 150 via line 130, and a polar solvent that is immiscible with the non-polar solvent is also fed to liquid / liquid extraction zone 150 via line 500. In an alternative embodiment ( Figure 1In the extraction zone 150 (not shown), the spent catalyst in line 126 and the polar solvent in line 500 are mixed before the combined stream is charged to the extraction zone 150. In the extraction zone 150, a non-polar phase comprising the non-polar solvent and the catalyst and a polar phase (e.g., raffinate) comprising the polar solvent and, for example, reaction byproducts and catalyst degradation products are formed. The non-polar phase is withdrawn from the extraction zone 150 via line 134 and fed to the distillation system 155. The polar phase is withdrawn from the extraction zone 150 via line 510 to the separation stage 1000.

[0100] The distillation system 155 is operated to recover the non-polar solvent as an overhead stream which is returned to the extraction zone 150 via line 130, with make-up non-polar solvent optionally being added to the overhead stream. The bottoms from the distillation system 155 contain partially purified catalyst which is collected and removed from the distillation system 155 via line 156 and introduced at any point for recycle to the first reaction zone Z. 1 In. Figure 1 In the embodiment of the present invention, the partially purified catalyst can be removed from the distillation column 155 through the pipeline 156 and transferred to the pipeline 146 for introduction into the catalyst recycle pipeline 140 for recycling to the first reaction zone Z 1 middle. Figure 1 Stream 146 is shown introduced downstream of withdrawn stream 126, but such stream may optionally be introduced upstream of withdrawn stream 126. Optionally, at least a portion of the partially purified catalyst stream in line 156 may be recycled to the second reaction zone Z. 2 In. Figure 1 The partially purified catalyst stream in line 156 may be transferred to line 246 for introduction into catalyst recycle line 240 for recycle to the second reaction zone Z. 2 Supplemental catalyst or catalyst components (additional zero-valent Ni and / or additional phosphorus-containing ligands) may be added to the first reaction zone and the second reaction zone via lines 145 and 245, respectively. 1 and Z 2 middle.

[0101] The separation system 1000 conveniently includes a plurality of distillation columns that separate the reaction byproducts and catalyst degradation products from the polar solvent, which is then returned to the extraction zone 150 via line 500 .

[0102] In the separation section 125, the first reaction zone Z 1 The product stream 200 containing 2M3BN separated from the reaction product is introduced into the second reaction zone Z through pipeline 240 2 In the second reaction zone, the second phosphorus-containing catalyst complex is supplied, and the second phosphorus-containing catalyst complex may be the same as or different from the first phosphorus-containing catalyst complex. 2In the second reaction zone Z, the conditions are controlled so that the 2M3BN undergoes isomerization to produce a reaction product substantially comprising 3PN. The effluent stream comprising the second phosphorus-containing catalyst complex and the 3PN product is removed from the second reaction zone Z via line 222. 2 The catalyst stream 240 is withdrawn from the separation section 225 and passed to the separation section 225 to obtain, inter alia, a 3PN product stream 300 and a concentrated catalyst stream 240. The separation section 225 may include one or more distillation columns.

[0103] exist Figure 1 In the particular embodiment shown, the second reaction zone Z 2 There is provided a means for recycling the catalyst to the second reaction zone Z 2 In this second catalyst recycling system, a portion of the concentrated catalyst stream in line 240 is diverted and fed to a liquid / liquid extraction zone 250 via line 226. A non-polar solvent, such as an alkane, is fed to the liquid / liquid extraction zone 250 via line 230, while a polar solvent that is immiscible with the non-polar solvent is also fed to the liquid / liquid extraction zone 250 via line 700. In one embodiment (not shown), the catalyst stream 226 and the polar solvent in line 700 are mixed before the combined streams are fed to the extraction zone 250. Additionally, the catalyst stream 226 and the polar solvent in line 700 are mixed before the combined streams are fed to the extraction zone 250. Figure 1 dinitrile from a source not shown in the figure (such as from the third reaction zone Z 3 A portion of the refined dinitrile product stream) can be added to the extraction zone 250 as needed to achieve the desired phase separation and extraction.

[0104] In the extraction zone 250, a non-polar phase comprising the non-polar solvent and the catalyst and a polar phase (e.g., raffinate) comprising, for example, the polar solvent, reaction byproducts, and certain catalyst degradation products are formed. The non-polar phase is removed from the extraction zone 250 via line 234 and fed to the distillation system 255. The polar phase is removed from the extraction zone 250 and fed to the separation stage 2000 via line 710.

[0105] The distillation system 255 is operated to recover the non-polar solvent as an overhead stream which is returned to the extraction zone 250 via line 230, with make-up non-polar solvent optionally added to the overhead stream. The bottoms from the distillation system 255 include partially purified catalyst which may be removed via line 248 for introduction into the catalyst recycle line 240 for recycle to the second reaction zone Z. 2 Optionally, a side stream can be taken from line 248 and enters line 247, and this side stream can be used as the first reaction zone Z 1 The catalyst is fed, for example, by introducing a side stream from line 247 into line 146 or line 140. It is then fed to the second reaction zone Z 2Any partially purified catalyst stream may be provided with additional zero-valent Ni and / or phosphorus-containing ligands, for example via line 245. Although not described in Figure 1 245, but line 245 may optionally feed directly into line 246 or line 248 rather than line 240. Other means of introducing make-up catalyst are known in the art and may be used.

[0106] The separation system 2000 conveniently includes a plurality of distillation columns that separate the reaction by-products and catalyst degradation products from the polar solvent, which is then returned to the extraction zone 250 via line 700 .

[0107] although Figure 1 Not shown, but the first reaction zone Z 1 and the second reaction zone Z 2 A single catalyst recovery system may be shared. A shared catalyst recovery system may be desirable when the first phosphorus-containing ligand and the second phosphorus-containing ligand are the same. In such a shared system, the following features may be eliminated or shut down: lines 226, 230, 234, 247, 248, 700, and 710; extraction zone 250; distillation unit 255; and separation section 2000. Instead of withdrawing a purge stream via line 226, a purge stream may be withdrawn via line 227 and introduced into line 126 or directly into extraction zone 150. In such a shared catalyst recovery system, the first phosphorus-containing ligand and the second phosphorus-containing ligand may be separated from each other by a catalyst recovery system. 2 Any partially purified catalyst stream will be purified by Figure 1 Lines 246 and 240 are configured as shown.

[0108] In the separation section 225, the second reaction zone Z 2 The 3PN product separated from the reaction product is introduced into the third reaction zone Z via pipeline 300 3 The third reaction zone also receives a supply of HCN via line 220. 3PN from separation section 125 may also be supplied via Figure 1 One or more pipelines not shown in the third reaction zone Z 3 A third catalyst comprising, for example, zero-valent Ni and a third phosphorus-containing ligand (collectively referred to as a third catalyst system) and a Lewis acid promoter is introduced into the third reaction zone Z via line 340. 3 3PN and HCN in the third reaction zone Z 3 The reaction in the reaction zone produces a reaction product containing adiponitrile. 3 The reaction product stream is taken out. The reaction product stream comprises, for example, adiponitrile, catalyst, promoter and unreacted reactants. Before the catalyst is separated from the adiponitrile product, the reaction product stream may optionally be passed through a separation section ( Figure 1 (not shown) to remove unreacted reactants.

[0109] The catalyst and adiponitrile product of the product stream in line 400 are passed into the liquid / liquid extraction zone 370. A non-polar solvent (such as an alkane) is fed into the liquid / liquid extraction zone 370 via line 330. The non-polar solvent introduced into the liquid / liquid extraction zone 370 may have the same or different composition as the non-polar solvent introduced into the liquid / liquid extraction zone 150. The non-polar solvent from line 330 and the adiponitrile product from line 400 together constitute an extractant system of immiscible components. In the extraction zone 370, a non-polar phase comprising a non-polar solvent and a catalyst and a polar phase (e.g., raffinate) comprising adiponitrile, a promoter, and catalyst degradation products are formed. The non-polar phase is taken out from the extraction zone 370 to the distillation system 375 via line 334. The polar phase comprising adiponitrile is taken out from the extraction zone 370 and fed to the adiponitrile purification section 3000 via line 600.

[0110] The distillation system 375 is operated to recover the non-polar solvent as an overhead stream, which is returned to the extraction zone 370 via line 330, optionally with make-up non-polar solvent added to the overhead stream. The bottoms from the distillation system 375 include partially purified catalyst and can be removed from the distillation system 375 via line 340 for recycling to the third reaction zone Z. 3 A supplemental amount of additional zero-valent Ni and / or a third phosphorus-containing ligand along with a promoter may be added to the partially purified catalyst in line 340 via line 345 .

[0111] Adiponitrile purification section 3000 may collectively include a series of distillation columns that provide separation of impurities (such as reaction byproducts and catalyst degradation products) from a purified adiponitrile product (which is recovered in line 660). A portion of the purified adiponitrile product may optionally be returned to extraction zone 150 or extraction zone 250 (via Figure 1 lines not shown) to facilitate phase separation in these extraction zones.

[0112] The present invention will now be described in more detail with reference to the following non-limiting examples.

[0113] In the examples, the term "DN distribution" refers to the percentage of ADN produced based on the total dinitriles in the product and is calculated as 100*ADN / (ADN+MGN+ESN).

[0114] Comparative Example 1 - Synthesis of nickel complex solution of 2'-(bis(o-tolyloxy)methoxy)-[1,1'-di(cyclohexane)]-2-yl phosphite di-o-tolyl ester.

[0115] Comparative Example 2 - Synthesis of nickel complex solution of diisopropyl 2,2'-bis((bis(o-tolyloxy)phosphinoyl)oxy)-[1,1'-binaphthyl]-3,3'-dicarboxylate.

[0116] Comparative Example 3 - Isomerization of 2-methyl-3-butenenitrile using a nickel complex solution of 2'-(bis(o-tolyloxy)methoxy)-[1,1'-di(cyclohexane)]-2-yl phosphite di-o-tolyl ester.

[0117] Comparative Example 4 - Isomerization of 2-methyl-3-butenenitrile using a nickel complex solution of diisopropyl 2,2'-bis((bis(o-tolyloxy)phosphinoyl)oxy)-[1,1'-binaphthyl]-3,3'-dicarboxylate.

[0118] Comparative Example 5 - Hydrocyanation of 3PN using a nickel complex solution of 2'-(bis(o-tolyloxy)methoxy)-[1,1'-di(cyclohexane)]-2-yl phosphite di-o-tolyl ester.

[0119] Comparative Example 6 - Hydrocyanation of 3PN using a nickel complex solution of diisopropyl 2,2'-bis((bis(o-tolyloxy)phosphinoyl)oxy)-[1,1'-binaphthyl]-3,3'-dicarboxylate.

[0120] Experimental Example 1. Synthesis of the nickel complex of ligand A by the dissolved metal method .

[0121] In a glove box with an argon atmosphere, 0.43 g of nickel metal powder, 0.97 g of ligand A (produced as described above), 0.05 g of zinc chloride, and 5.50 g of 3-pentenenitrile were combined in a 10 mL serum bottle sealed with a polytetrafluoroethylene-lined septum. The solution was stirred with a magnetic stirrer at 65° C. for 21 hours to obtain a solution of the nickel complex of ligand A in 3-pentenenitrile solution. The concentration of the nickel complex of ligand A in the solution was measured by high performance liquid chromatography.

[0122] Experimental Example 2. Synthesis of the Nickel Complex of Ligand B by Dissolved Metal Method .

[0123] The procedure of Experimental Example 1 was repeated except that ligand B was used instead of ligand A.

[0124] Experimental Example 3. Synthesis of the Nickel Complex of Ligand C by the Dissolved Metal Method .

[0125] The procedure of Experimental Example 1 was repeated except that ligand C was used instead of ligand A.

[0126] Comparative Example 1 - Synthesis. 2'-(bis(o-tolyloxy)methoxy)-[1,1'-di(cyclohexane)]-2-yl phosphite di-o-tolyl ester "CEx1" was prepared according to the procedure of WO 99 / 06357 A1 and the corresponding nickel complex was synthesized following the procedure of Experimental Example 1, but with Ligand A substituted for CEx1.

[0127]

[0128] Comparative Example 2 - Synthesis. Diisopropyl 2,2'-bis((bis(o-tolyloxy)phosphinoyl)oxy)-[1,1'-binaphthyl]-3,3'-dicarboxylate "CEx2" was prepared according to the procedure of WO 99 / 06357 A1 and the corresponding nickel complex was synthesized following the procedure of Experimental Example 1, but using Ligand A in place of CEx2.

[0129]

[0130] Experimental Example 4. Preparation of 2-methyl-3-butenenitrile using the nickel complex solution prepared in Experimental Example 1 Isomerization .

[0131] A portion (0.50 g) of the solution containing the nickel catalyst from Experimental Example 1 was filtered and charged into a 5 mL glass serum vial together with 5.00 g of 2-methyl-3-butenenitrile. The resulting solution was heated to 100°C, maintained at that temperature for 5 hours, then cooled to room temperature and then analyzed by gas chromatography (GC) within 5 minutes of the end of the experiment. The conversion of 2M3BN was determined to be 77.1%, and the selectivity to 3-pentenenitrile was 89.1%.

[0132] Experimental Example 5. Preparation of 2-methyl-3-butenenitrile using the nickel complex solution prepared in Experimental Example 2 Isomerization .

[0133] The procedure of Experimental Example 4 was repeated, except that the nickel complex of ligand A was replaced by the nickel complex of ligand B. The conversion of 2M3BN was determined to be 79.1%, and the selectivity to 3-pentenenitrile was 87.3%.

[0134] Experimental Example 6. Determination of 2-methyl-3-butenenitrile using the nickel complex solution prepared in Experimental Example 3 Isomerization .

[0135] The procedure of Experimental Example 4 was repeated, except that the nickel complex of ligand A was replaced by the nickel complex of ligand C. The conversion of 2M3BN was determined to be 81.3%, and the selectivity to 3-pentenenitrile was 90.1%.

[0136] Comparative Example 3 - Isomerization of 2-methyl-3-butenenitrile (2M3BN) using the nickel complex of CEx1 The procedure of Experimental Example 4 was followed, but substituting the nickel complex of CEx1 for the nickel complex of Ligand A. The conversion of 2M3BN was determined to be 80%, and the selectivity to 3-pentenenitrile was 90%.

[0137] Comparative Example 4 - Isomerization of 2-methyl-3-butenenitrile (2M3BN) using the nickel complex of CEx2 The procedure of Experimental Example 4 was followed, but substituting the nickel complex of CEx2 for the nickel complex of Ligand A. The conversion of 2M3BN was determined to be 73% and the selectivity to 3-pentenenitrile was 91%.

[0138] Experimental Example 7. Hydrocyanation of 3-pentenenitrile using the nickel complex solution prepared in Experimental Example 1 .

[0139] To a temperature-controlled 50 mL glass reaction vessel equipped with a magnetic stirrer was added 2.5 grams of the solution prepared by the procedure of Experimental Example 1 and 5 mL of 3-pentenenitrile. The mixture was treated with HCN at a nitrogen flow rate of 0.01 mL / min at 70° C. for 1 hour. GC analysis of the resulting product mixture indicated an ADN yield of 73.6% and a DN distribution of 85.4%.

[0140] Experimental Example 8. Hydrocyanation of 3-pentenenitrile using the nickel complex solution prepared in Experimental Example 2 .

[0141] The procedure of Experimental Example 7 was repeated, except that the nickel complex of ligand B was substituted for the nickel complex of ligand A. GC analysis of the resulting product mixture indicated an ADN yield of 87.1% and a DN distribution of 86.0%.

[0142] Experimental Example 9. Hydrocyanation of 3-pentenenitrile using the nickel complex solution prepared in Experimental Example 3 .

[0143] The procedure of Experimental Example 7 was repeated, except that the nickel complex of ligand C was used in place of the nickel complex of ligand A. GC analysis of the resulting product mixture indicated an ADN yield of 84.1% and a DN distribution of 83.0%.

[0144] Comparative Example 5 - Hydrocyanation of 3-pentenenitrile The procedure of Experimental Example 7 was followed using the nickel complex solution prepared from CEx1, but substituting the nickel complex of ligand CEx1 for the nickel complex of ligand A. GC analysis of the resulting product mixture indicated an ADN yield of 32% and a DN distribution of 83%.

[0145] Comparative Example 6 - Hydrocyanation of 3-pentenenitrile The procedure of Experimental Example 7 was followed using the nickel complex solution prepared from CEx2, but substituting the nickel complex of ligand CEx2 for the nickel complex of ligand A. GC analysis of the resulting product mixture indicated an ADN yield of 36% and a DN distribution of 67%.

[0146] While the present invention has been described and illustrated by reference to particular embodiments, those skilled in the art will appreciate that the present invention lends itself to variations not necessarily illustrated herein. Therefore, reference should be made solely to the appended claims in order to determine the true scope of the present invention.

Claims

1. A process for the hydrocyanation of an organic compound containing at least one olefinic group, the process comprising reacting the organic compound with hydrogen cyanide in the presence of a catalyst complex comprising at least one transition metal and a phosphorus-containing ligand comprising a calixarene backbone and at least two aryl phosphite or aryl phosphoramidite groups chemically bonded to the backbone, in, When at least two aryl phosphite groups are chemically bonded to the backbone: (i) The phosphorus atom of each arylphosphite group is bonded to two adjacent benzene rings of the calixarene backbone through the oxygen atom of the hydroxyl group of the calixarene, and each phosphorus atom has -OR 2 Substituents, where R 2 is a phenyl ring substituted with 1 to 5 primary alkyl groups, and all other carbon atoms are unsubstituted; or (ii) the phosphorus atom of each aryl phosphite group is bonded to a benzene ring of the calixarene backbone through one or more oxygen atoms of one or more hydroxyl groups of the calixarene, and the phosphorus atom has two -OR 3 Substituents, where R 3 is an optionally substituted aryl group.

2. The method of claim 1, wherein the organic compound comprises 1,3-butadiene.

3. The method of claim 1, wherein the organic compound comprises 3-pentenenitrile.

4. A method for double bond isomerization of monoolefinically unsaturated compounds, wherein the compounds are contacted with a catalyst complex comprising at least one transition metal and a phosphorus-containing ligand, the phosphorus-containing ligand comprising a calixarene backbone and at least two aryl phosphite or aryl phosphoramidite groups chemically bonded to the backbone, wherein: When at least two aryl phosphite groups are chemically bonded to the backbone: (i) The phosphorus atom of each arylphosphite group is bonded to two adjacent benzene rings of the calixarene backbone through the oxygen atom of the hydroxyl group of the calixarene, and each phosphorus atom has -OR 2 Substituents, where R 2 is a phenyl ring substituted with 1 to 5 primary alkyl groups, and all other carbon atoms are unsubstituted; or (ii) the phosphorus atom of each aryl phosphite group is bonded to a benzene ring of the calixarene backbone through one or more oxygen atoms of one or more hydroxyl groups of the calixarene, and the phosphorus atom has two -OR 3 Substituents, where R 3 is an optionally substituted aryl group.

5. The method of claim 4, wherein the monoethylenically unsaturated compound comprises 2-methyl-3-butenenitrile.

6. A method according to any preceding claim, wherein R 2 yes .

7. A method according to any preceding claim, wherein the calixarene backbone comprises four benzene rings connected by methylene groups.

8. A method according to any preceding claim, wherein each benzene ring of the calixarene backbone is substituted with a tert-butyl group at the meta position relative to the attached methylene group.

9. A method according to any preceding claim, wherein the phosphorus-containing ligand comprises a calixarene backbone and at least two aryl phosphoramidite groups chemically bonded to the backbone.

10. The method according to claim 9, wherein each aryl phosphoramidite group is bonded to two adjacent benzene rings of the calixarene backbone through the oxygen atom of the hydroxyl group of the calixarene, and wherein the phosphorus atom has -NHR 3 Substituents, where R 3 is an optionally substituted aryl group.

11. The method according to claim 10, wherein R 3is a phenyl ring optionally substituted with at least one alkyl group.

12. The method according to claim 10, wherein R 3 is a phenyl ring substituted by 1 to 5 C1-C4 alkyl groups, preferably 1 to 5 methyl groups.

13. The method according to any one of claims 1 to 8, wherein the phosphorus-containing ligand comprises a calixarene backbone and at least two aryl phosphite groups chemically bonded to the backbone, and the phosphorus atom of each aryl phosphite group is bonded to a benzene ring of the calixarene backbone through one or more oxygen atoms of one or more hydroxyl groups of the calixarene, wherein R 3 is a phenyl ring optionally substituted with at least one alkyl group.

14. The method according to claim 13, wherein R 3 is a phenyl ring substituted by 1 to 5 C1-C4 alkyl groups, preferably 1 to 5 methyl groups.

15. The method according to claim 13 or claim 14, wherein the benzene rings of the calixarene backbone that do not carry arylphosphite substituents are replaced by one or more C 1-4 Alkoxy groups are substituted.

16. The method according to any one of claims 1 to 8, wherein R 2 is a phenyl ring substituted with 1 to 5 C1-C4 primary alkyl groups, and all other carbon atoms are unsubstituted.

17. The method according to any one of claims 1 to 8, wherein R 2 is a phenyl ring substituted with 1 to 5 methyl groups, and all other carbon atoms are unsubstituted.

18. A method according to any preceding claim, wherein the phosphorus-containing ligand is selected from the group consisting of: and .

19. The method of any preceding claim, wherein the at least one transition metal comprises nickel.

20. A phosphorus-containing ligand having one of the following structures: and .

21. A catalyst complex comprising the multidentate phosphite ligand of claim 19 and at least one transition metal.

22. The catalyst complex of claim 21, wherein the at least one transition metal comprises nickel.

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