Arsenic-containing ligands, catalytic compositions containing such ligands, and catalytic processes utilizing such catalytic compositions

Abstract

A ligand containing arsenic and having formula (I): wherein n is 2 and the ligand is bidentate; each X is O or NH; and Ar1 and Ar2 may be the same or different and each is an aryl group, with the proviso that each Ar1 group attached to the same As atom may combine to form a single aryl group. # imgabs0 #

Description

Citation of Related Applications

[0001] This application claims the benefit of U.S. Provisional Application No. 63 / 394,310, filed on August 2, 2022, and UK Application No. 2215094.0, 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 arsenic-containing ligands, catalytic compositions containing such ligands, and catalytic methods utilizing such catalytic compositions. Background Art

[0003] Phosphorus-containing ligands are ubiquitous in catalysis and are used in many commercially important chemical transformations. Phosphorus ligands commonly encountered in catalysis include phosphines (A) and phosphites (B), as shown below. In these representations, R can be virtually any organic group. Monophosphine and monophosphite ligands are compounds containing a single phosphorus atom that acts as a metal donor. Diphosphine, diphosphite, and bis(phosphorus) ligands typically contain two phosphorus-donating atoms and often form cyclic chelate structures with transition metals.

[0004]

[0005] There are several commercially important catalytic processes that employ phosphorus-containing ligands. For example, U.S. Pat. No. 5,910,600 to Urata et al. discloses that bisphosphite compounds can be used as constituent elements of homogeneous metal catalysts for various reactions such as hydrogenation, hydroformylation, hydrocyanation, hydrocarboxylation, hydroamidation, hydroesterification, and aldol condensation.

[0006] Some of these catalytic methods are used for the commercial production of polymers, solvents, plasticizers and other commodity chemicals. For example, the hydrocyanation of 1,3-butadiene and / or 3-pentenenitrile is a well-known approach to produce adiponitrile, which is a precursor for producing nylon-6,6. Therefore, due to the huge global chemical commodity market, in any of these commercially important reactions, even small incremental improvements in yield or selectivity are highly desirable. In addition, it is also highly desirable to find certain ligands that can be used for applications across a range of these commercially important reactions, not only for commercial benefit, but also in order to be able to merge and focus research and development efforts on a specific group of compounds.

[0007] U.S. Pat. No. 5,512,696 to Kreutzer et al. discloses a hydrocyanation process using a multidentate phosphite ligand, and the patents and publications cited therein describe hydrocyanation catalyst systems pertaining to the hydrocyanation of olefinically unsaturated compounds. U.S. Pat. Nos. 5,723,641, 5,663,369, 5,688,986, and 5,847,191 disclose processes and catalyst compositions for the hydrocyanation of monoolefinically unsaturated compounds using zero-valent nickel and a multidentate phosphite ligand and a Lewis acid co-promoter.

[0008] U.S. Pat. No. 5,821,378 to Foo et al. discloses a liquid phase process for hydrocyanating diene compounds to produce non-conjugated acyclic nitriles and a liquid phase process 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 a multidentate phosphite ligand. 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 a multidentate phosphite ligand having an alkyl ether substituent on the carbon ortho to the terminal phenol group, which is used in a liquid phase process for hydrocyanating diene compounds to produce non-conjugated acyclic nitriles and a liquid phase process for isomerizing those nitriles to 3-monoolefin linear nitriles and / or 4-monoolefin linear nitriles.

[0009] Although the above-mentioned phosphorus-containing catalyst systems may represent commercially viable catalysts, it is still desirable to provide even more effective, higher performance catalyst precursor compositions, catalytic compositions, and catalytic methods to realize the full commercial potential of the desired reactions. Effectiveness and / or performance may be achieved in any or all of rapidity, selectivity, efficiency, or stability, depending on the reaction being performed. It is also desirable to provide such improved catalyst systems and / or methods that can be optimized for one or more commercially important reactions such as hydroformylation, hydrocyanation, or isomerization. Summary of the invention

[0010] In accordance with the present invention, it has now been discovered that certain arsenic-containing ligands, when complexed with transition metals, are effective catalysts in a number of commercially important chemical processes such as hydrocyanation and double bond isomerization.

[0011] Therefore, in one aspect, the present application provides a ligand containing arsenic (As) and having formula (I):

[0012]

[0013] Where n is 2 and the ligand is bidentate;

[0014] each X is O or NH; and

[0015] Ar 1and Ar 2 can be the same or different and are each an aryl group, provided that each Ar is attached to the same As atom 1 The groups can be combined to form a single aryl group.

[0016] In another aspect, the present application provides a ligand containing arsenic and having one of the following structures:

[0017]

[0018] and

[0019]

[0020] In other aspects, the present application provides a catalyst complex comprising an arsenic-containing ligand as described herein and at least one transition metal.

[0021] In yet another 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 containing at least one transition metal and a ligand containing arsenic (As) and having formula (I):

[0022]

[0023] wherein n is 1 and the ligand is monodentate, or n is 2 and the ligand is bidentate;

[0024] each X is O or NH; and

[0025] Ar 1 and Ar 2 can be the same or different and are each an aryl group, provided that each Ar is attached to the same As atom 1 The groups can be combined to form a single aryl group.

[0026] In yet 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 containing at least one transition metal and a ligand containing arsenic (As) and having formula (I):

[0027]

[0028] wherein n is 1 and the ligand is monodentate, or n is 2 and the ligand is bidentate;

[0029] each X is O or NH; and

[0030] Ar 1and Ar 2 can be the same or different and are each an aryl group, provided that each Ar is attached to the same As atom 1 The groups can be combined to form a single aryl group. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] 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 1-3-butenenitrile, and hydrocyanating 3-pentenenitrile. DETAILED DESCRIPTION

[0032] Novel arsenic-containing ligands and catalyst complexes comprising the arsenic-containing ligands and at least one transition metal are described herein. Also described are catalytic processes using the catalyst complexes, such as the hydrocyanation of organic compounds containing at least one olefinic group, particularly 1,3-butadiene and 3-pentenenitrile, and the double bond isomerization of monoolefinically unsaturated compounds, such as 2-methyl-3-butenenitrile.

[0033] Arsenic ligands

[0034] In its broadest aspect, the novel arsenic-containing ligands have formula (I):

[0035]

[0036] wherein n is 1 and the ligand is monodentate, or n is 2 and the ligand is bidentate; each X is O or NH; and Ar 1 and Ar 2 may be the same or different and are each an aryl group, provided that each Ar is attached to the same As atom 1 The groups can be combined to form a single aryl group. 1 When the groups are combined to form a single aromatic group, preferably, Ar 1 The groups are bonded to each other by single bonds. As used herein, the term "aryl" refers to an aromatic carbocyclic or heterocyclic 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.

[0037] In an embodiment, each Ar 1 The group comprises a phenyl group optionally substituted by one or more alkyl groups having 1 to 4 carbon atoms. The phenyl groups attached to each As atom may be bonded to each other via a single bond. Preferably, each Ar 1The group comprises a phenyl group substituted by one or more alkyl groups having 1 to 4 carbon atoms, more preferably wherein the one or more alkyl groups are each independently selected from methyl and isopropyl. Most preferably, Ar 1 It is xylyl or 2-isopropyl-5-methylphenyl.

[0038] Preferably, all X groups are O or all X groups are NH.

[0039] Preferably, n is 2 and the ligand is bidentate, wherein Ar 2 Preferably, each Ar 2 The radical is an optionally substituted phenyl or naphthyl radical, wherein the phenyl rings or naphthyl rings are bonded to each other to form a biphenyl group or a binaphthyl group.

[0040] Thus, preferably, all X groups are O or all X groups are NH, n is 2 and the ligand is bidentate, wherein Ar 2 The groups are bonded to each other to form a biphenyl group or a binaphthyl group, each of which may be optionally substituted, and wherein each Ar 1 The group preferably comprises a phenyl group substituted by one or more alkyl groups having 1 to 4 carbon atoms. More preferably, all X groups are O or all X groups are NH, n is 2 and the ligand is bidentate, wherein Ar 2 The groups are bonded to each other to form a biphenyl group, which may be optionally substituted, and wherein each Ar 1 The group preferably comprises a phenyl group substituted by one or more alkyl groups having 1 to 4 carbon atoms. The biphenyl and binaphthyl groups may be substituted by one or more substituents independently selected from alkyl groups having 1 to 6 carbon atoms and alkoxy groups having 1 to 6 carbon atoms, preferably alkyl groups having 1 to 4 carbon atoms and alkoxy groups having 1 to 4 carbon atoms.

[0041] The arsenic-containing ligand may have one of the following structures (I) or (II):

[0042]

[0043]

[0044] Wherein X is O or NH;

[0045] Each R 1 The groups are independently selected from H and alkyl groups having 1 to 4 carbon atoms, or one R on each phenyl ring attached to the As atom 1 The group may be missing and replaced by a single bond connecting the two rings;

[0046] Each R2 The groups are independently selected from H, alkyl groups having 1 to 6 carbon atoms, and alkoxy groups having 1 to 6 carbon atoms.

[0047] Preferably, in formula (I) and (II), both X groups are O or both X groups are NH. Preferably, each R 1 independently selected from H, methyl and isopropyl, or one R on each phenyl ring attached to the As atom 1 The group may be missing and replaced by a single bond connecting the two rings. Preferably, each R 2 Independently selected from H, alkyl groups having 1 to 4 carbon atoms, and alkoxy groups having 1 to 4 carbon atoms.

[0048] Therefore, in formula (I) and (II), it is particularly preferred that all X groups are O or all X groups are NH; each R 1 independently selected from H, methyl and isopropyl, or one R on each phenyl ring attached to the As atom 1 The group may be absent and replaced by a single bond connecting the two rings; and each R 2 Independently selected from H, alkyl groups having 1 to 4 carbon atoms, and alkoxy groups having 1 to 4 carbon atoms.

[0049] Disclosed are arsenic-containing ligands according to formula (I), wherein all X groups are O or all X groups are NH; each R 1 independently selected from H and an alkyl group having 1 to 4 carbon atoms, or one R on each phenyl ring attached to the As atom 1 The group may be missing and replaced by a single bond connecting the two rings; preferably wherein each R 1 are independently selected from H, methyl and isopropyl; and

[0050] Each R 2 independently selected from H, alkyl groups having 1 to 6 carbon atoms and alkoxy groups having 1 to 6 carbon atoms, preferably wherein each R 2 Independently selected from H, alkyl groups having 1 to 4 carbon atoms, and alkoxy groups having 1 to 4 carbon atoms.

[0051] Disclosed are arsenic-containing ligands according to formula (II), wherein all X groups are O or NH, preferably O; each R 1 independently selected from H and an alkyl group having 1 to 4 carbon atoms, or one R on each phenyl ring attached to the As atom 1 The group may be missing and replaced by a single bond connecting the two rings; preferably wherein each R 1 are independently selected from H, methyl and isopropyl; and

[0052] Each R 2 independently selected from H, alkyl groups having 1 to 6 carbon atoms and alkoxy groups having 1 to 6 carbon atoms, preferably wherein each R 2 Independently selected from H, alkyl groups having 1 to 4 carbon atoms, and alkoxy groups having 1 to 4 carbon atoms.

[0053] Non-limiting examples of suitable arsenic-containing ligands include the following:

[0054] Ligand A

[0055]

[0056] Ligand B

[0057]

[0058] Ligand C

[0059]

[0060] Ligand D

[0061] Synthesis of Arsenic-Containing Ligands

[0062] The novel arsenic-containing ligand of formula (I), wherein X is NH, can be prepared by the following method: firstly, 1 NH2 arylamine or formula Ar 1 The aryl diamine of (NH2)2 is reacted with arsenic trichloride so that the molar ratio of NH2 groups to arsenic trichloride is at least 2. The resulting amidoarsenochlorodite can then be reacted with a 2 (NH2) x (where x is 1 or 2) to produce the desired ligand. For example, triphenylamine arsenic ligand A can be prepared by reacting 2 equivalents of 2,4-benzylidene with 1 equivalent of arsenic trichloride in diethyl ether at 0°C to give amino arsenic chlorite, and then reacting 2 equivalents of amino arsenic chlorite with 1 equivalent of diphenylamine backbone in toluene at room temperature to give the desired ligand.

[0063] Similarly, the novel arsenic-containing ligand of formula (I), wherein X is O, can be prepared by first reacting a ligand of formula Ar 1 OH aromatic alcohol or formula Ar 1 (OH)2 aryl diol is reacted with arsenic trichloride so that the molar ratio of OH groups to arsenic trichloride is at least 2. The resulting arsenic chlorite can then be reacted with a compound of the formula Ar'OH x(where x is 1 or 2) to produce the desired ligand. Thus, arsenite ligand B can be prepared by reacting 2 equivalents of 2,4-dimethylphenol with 1 equivalent of arsenic trichloride in diethyl ether at 0°C to give arsenic chlorite, and then reacting 2 equivalents of arsenic chlorite with 1 equivalent of 2,2'-biphenol skeleton in toluene at room temperature to give the desired ligand. The synthesis of ligands C and D can be accomplished by following the synthetic procedure for ligands A and B, and replacing 2,4-dimethylaniline with 2-isopropyl-5-methylphenol and biphenol with binaphthol in the case of ligand C. For ligand D, when preparing chlorite, one equivalent of biphenol should be used instead of 2 equivalents of 2,4-dimethylaniline, and the appropriately substituted biphenol as described above should be applied.

[0064] Catalyst complex

[0065] The arsenic-containing ligands disclosed herein can be used to form catalyst complexes (chelates) in combination with transition metals. The catalyst complexes can be used for olefin hydrocyanation, for example, the hydrocyanation of dienes (such as 1,3-butadiene). In particular, for the hydrocyanation of monoolefins (such as 3-pentenenitrile), a catalyst promoter (such as a Lewis acid) can be optionally used.

[0066] The transition metal used in the catalyst complex can be any transition metal capable of the desired catalytic conversion and can additionally contain unstable ligands which are displaced during the catalytic reaction or which play an active role in the catalytic conversion. Any transition metal is contemplated in this regard. Preferred metals are those comprising Group VIII of the Periodic Table. Preferred metals for hydrocyanation and / or isomerization are nickel, cobalt and palladium, with nickel being particularly preferred for olefin hydrocyanation.

[0067] Nickel complexes of each of the arsenic ligands described herein are disclosed.

[0068] Nickel compounds can be prepared or generated according to techniques well known in the art, as described, for example, in 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 replaced by organoarsenic 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(Oo-C6H4CH3)3}2 (C2H4), both of which are known in the art. Alternatively, a divalent nickel compound can be combined with a reducing agent to be used as a nickel source in the reaction. Suitable divalent nickel compounds include compounds of the formula NiY2, 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 H2.

[0069] U.S. Patent No. 10,537,885 describes a method for preparing zero-valent nickel that is highly active for complexing with phosphorus-containing ligands and includes calcining a first nickel(II)-containing particle in an atmosphere containing an oxidizing component and at a temperature typically 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 that is not generated by the reduction, and wherein a H2 / Ni molar ratio of about 1.9 to 2.5 is employed during the reduction step.

[0070] 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.

[0071] 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.

[0072] 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 ZnBr2, ZnI2, ZnCl2, ZnSO4, CuCh, CuCl, Cu(O3SCF3)2, CoCl2, CoI2, FeI2, FeCl3, FeCl2, FeCl2(THF)2, TiCl4(THF)2, TIC14, TIC13, ClTi(OiPr)3, MnCl2, ScCl3, AlCl3, (C8H 17 )A1C12、(C8H17 )2AlCl, (iso-C4H9)2A1C1, Ph2AICI, PhAlCl2, ReCl5, ZrCl4, NbCl5, VC13, CrCl2, MoCl5, YCl3, CdCl2, LaCl3, Er(O3SCF3)3, Yb(O2CCF3)3, SmCl3, B(C6Hs)3, TaCl5. 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 ZnCl2, CoI2, and SnCl2 and organometallic compounds such as RAlCl2, R3SnO3SCF3, and R3B, where R is an alkyl group or an aryl group. U.S. Pat. No. 4,874,884 describes how to select a synergistic combination of promoters to increase the catalytic activity of a catalyst system. Preferred promoters include CdCl2, FeCl2, ZnCl2, B(C6H5)3 and (C6H5)3SnX, where X is CF3SO3, CH3C6H5SO3 or (C6H5)3BCN. The molar ratio of promoter to nickel present in the reaction may range from about 1:16 to about 50:1.

[0073] Catalytic method using a catalyst complex

[0074] The above catalyst complex can be used for a variety of catalytic reactions, such as hydrogenation, hydroformylation, hydrocyanation, hydrocarboxylation, hydroamidation, hydroesterification, double bond isomerization and aldol condensation. Preferred reactions include hydroformylation (where olefins react with carbon monoxide and hydrogen to produce aldehydes), isomerization of monoolefinic unsaturated compounds (particularly nitriles), and especially hydrocyanation (where olefins react with hydrogen cyanide to produce nitrile). A particularly preferred use of the above catalyst complex wherein the transition metal is nickel is for the catalytic hydrocyanation of 1,3-butadiene to produce 3-pentenenitrile, which is then converted to adiponitrile. In an embodiment, in a 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 1-3-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 may be the above catalyst complex.

[0075] 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.

[0076]

[0077] 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.

[0078] In the presence of transition metal complexes containing various arsenic-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.

[0079]

[0080] 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 arsenic-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 arsenic-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.

[0081] The effluent stream containing 3PN can be recovered from the second reaction zone. In addition, 3PN is also typically 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 arsenic-containing ligand in a third reaction step in a third reaction zone. 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.

[0082] 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.

[0083] Conversion of 1,3-butadiene to 3-pentenenitrile

[0084] 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.

[0085] 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.

[0086] 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.

[0087] 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).

[0088] 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.

[0089] 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.

[0090] 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.

[0091] Separation of the product from the first reaction zone

[0092] The reaction of 1,3-butadiene and hydrogen cyanide in the presence of a first catalyst in a first reaction zone 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 arsenic-containing ligands, such as less than 350 parts per million parts by weight of arsenic-containing ligands, such as less than 200 parts per million parts by weight of arsenic-containing ligands.

[0093] 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 an arsenic-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 withdrawn from the upper withdrawal outlet. This stream is depleted in at least one arsenic-containing ligand relative to the arsenic-containing ligand feed stream fed to the distillation column. The pentenenitrile-depleted stream can be withdrawn from the bottom withdrawal outlet. Relative to the arsenic-containing ligand feed stream fed to the distillation column, this pentenenitrile-depleted stream is rich in arsenic-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 1-3-butenenitrile.

[0094] The pentenenitrile-rich stream comprising 3-pentenenitrile and 2-methyl-1-3-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-1-3-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.

[0095] 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.

[0096] 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.

[0097] Isomerization of 2-methyl-3-butenenitrile

[0098] A stream rich in 2-methyl-3-butenenitrile (2M3BN) separated from the effluent of the first reaction zone 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 arsenic-containing ligand is used for the second catalyst complex, the molar ratio of the monodentate ligand to zero-valent nickel in the catalyst for the 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 the isomerization reaction may be from 1:1 to 10:1, for example, from 1:1 to 5:1.

[0099] 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.

[0100] Separation of the product from the second reaction zone

[0101] 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 less than 500 parts per million parts by weight of arsenic-containing ligands. For example, the second stream rich in 3-pentenenitrile can contain less than 300ppm, for example, less than 100ppm of arsenic-containing ligands.

[0102] 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.

[0103] 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.

[0104] 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 arsenic-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 arsenic-containing ligand, a portion of the catalyst can be passed into the first reaction zone.

[0105] 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.

[0106] Hydrocyanation of 3-pentenenitrile to adiponitrile

[0107] 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 arsenic-containing catalyst complex to produce adiponitrile.

[0108] The 3-pentenenitrile feed to the third reaction zone is obtained from the above-mentioned distillation step and can generally contain at least 95 wt% 3PN, less than 5 wt% pentenenitrile other than 3PN and less than 0.1 wt% of the first arsenic-containing ligand. The 3PN feed can contain 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 C9 mononitriles.

[0109] 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.

[0110] The third arsenic-containing catalyst complex generally comprises a transition metal (such as zero-valent nickel) and a monodentate or bidentate arsenic-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 arsenic-containing catalyst complex generally includes one or more promoters to improve the production of dinitrile. As known in the art, promoters affect catalyst activity and selectivity to desired ADN. The promoters used include salts of metals with atomic numbers of 13, 21-32, 39-50 and 57-80, such as zinc, and compounds of formula BR'3, wherein R' is an alkyl or aryl radical of up to 18 carbon atoms, such as triphenylboron. The anion of this metal salt may include a halide, such as chloride, sulfate, phosphate and a low-order aliphatic carboxylate. Useful promoters are generally referred to as Lewis acids in the art. In one embodiment, when the Lewis acid promoter is ZnCl2, the molar ratio of promoter to nickel in the third catalyst complex may be 1:20 to 50:1, such as 0.2:1 to 2:1.

[0111] 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 arsenic-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%.

[0112] 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.

[0113] Separation of the product from the third reaction zone

[0114] 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.

[0115] 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.

[0116] 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 Z1 via pipeline 100, which also receives a supply of hydrogen cyanide via pipeline 120, and receives a supply of the first arsenic-containing catalyst complex via pipeline 140. In the first reaction zone Z1, conditions are controlled so that 1,3-butadiene reacts with hydrogen cyanide to produce a reaction product substantially comprising 3-pentenenitrile (3PN) and 2-methyl-3-butenenitrile (2M3BN). The reaction effluent stream is removed from the first reaction zone Z1 via pipeline 122 and introduced into a separation section 125 to obtain, in particular, 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 can be Figure 1 The feed stream containing 3-pentenenitrile (3PN) can also be recycled to the first reaction zone Z1 through a pipeline not shown in FIG. Figure 1 A pipeline not shown in FIG. 1 is taken out from the separation section 125 .

[0117] A portion of the catalyst separated from the reaction products in separation section 125 is recycled to first reaction zone Z1 via line 140, while another portion of the catalyst is 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.

[0118] 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 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 Z1. Figure 1 In the embodiment of the present invention, partially purified catalyst can be removed from distillation column 155 through pipeline 156 and transferred to pipeline 146 for introduction into catalyst recycle pipeline 140 for recycling to the first reaction zone Z2. 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 second reaction zone Z2. Figure 1 In the embodiment of the present invention, the partially purified catalyst stream in line 156 can be transferred to line 246 for introduction into catalyst recycle line 240 for recycling to the second reaction zone Z2. Make-up catalyst or catalyst components (additional zero-valent Ni and / or additional arsenic-containing ligands) can be added to the first and second reaction zones Z1 and Z2 via lines 145 and 245, respectively.

[0119] The separation system 1000 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 150 via line 500 .

[0120] The product stream 200 containing 2M3BN separated from the reaction product of the first reaction zone Z1 in the separation section 125 is introduced into the second reaction zone Z2 through pipeline 240, and the second reaction zone receives a supply of a second arsenic-containing catalyst complex, which can be the same or different from the first arsenic-containing catalyst complex. In the second reaction zone Z2, the conditions are controlled so that the 2M3BN undergoes isomerization to produce a reaction product substantially containing 3PN. The effluent stream containing the second arsenic-containing catalyst complex and the 3PN product is taken out from the second reaction zone Z2 via pipeline 222 and passed into the separation section 225 to obtain, in particular, a 3PN product stream 300 and a concentrated catalyst stream 240. The separation section 225 may include one or more distillation columns.

[0121] exist Figure 1 In the particular embodiment shown, the second reaction zone Z2 is provided with a second catalyst recovery system for recycling catalyst to the second reaction zone Z2. In this second catalyst recycle system, a portion of the concentrated catalyst stream in line 240 is diverted and fed to the 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 drawing (such as a portion of the refined dinitrile product stream from the third reaction zone Z3) may be added to the extraction zone 250 as needed to accomplish the desired phase separation and extraction.

[0122] 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.

[0123] 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 being 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 recycling to the second reaction zone Z2. Optionally, a side stream may be taken from line 248 and enter line 247, and this side stream may be used as catalyst feed to the first reaction zone Z1, for example by introducing the side stream from line 247 into line 146 or line 140. Any partially purified catalyst stream subsequently fed to the second reaction zone Z2 may be provided with additional zero-valent Ni and / or arsenic-containing ligands, for example via line 245. Although not described herein, the catalyst feed may be provided with additional zero-valent Ni and / or arsenic-containing ligands. 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.

[0124] The separation system 2000 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 250 via line 700 .

[0125] although Figure 1 1, but the first reaction zone Z1 and the second reaction zone Z2 may share a single catalyst recovery system. A shared catalyst recovery system may be desirable when the first arsenic-containing ligand and the second arsenic-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 apparatus 255; and separation section 2000. Instead of withdrawing a purified stream via line 226, a purified 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, any partially purified catalyst stream entering the second reaction zone Z2 would be removed by a purification step according to Figure 1 Lines 246 and 240 are configured as shown.

[0126] The 3PN product separated from the reaction product of the second reaction zone Z2 in separation section 225 is introduced into the third reaction zone Z3 via pipeline 300, and the third reaction zone also receives a supply of HCN via pipeline 220. The 3PN from separation section 125 can also be introduced into the third reaction zone Z3 via pipeline 300. Figure 1One or more pipelines not shown in the figure are introduced into the third reaction zone Z3. A third catalyst comprising, for example, zero-valent Ni and a third arsenic-containing ligand (collectively referred to as the third catalyst system) and a Lewis acid promoter is introduced into the third reaction zone Z3 through a pipeline 340. The reaction of 3PN and HCN in the third reaction zone Z3 produces a reaction product containing adiponitrile. A reaction product stream is taken out from the third reaction zone Z3 through a pipeline 400. The reaction product stream contains, for example, adiponitrile, a catalyst, a promoter, and unreacted reactants. Before separating the catalyst from the adiponitrile product, the reaction product stream may optionally be passed through a separation section ( Figure 1 (not shown) to remove unreacted reactants.

[0127] 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.

[0128] 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, with make-up non-polar solvent optionally 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 Z3. Make-up amounts of additional zero-valent Ni and / or a third arsenic-containing ligand along with a promoter can be added to the partially purified catalyst in line 340 via line 345.

[0129] 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.

[0130] The present invention will now be described in more detail with reference to the following non-limiting examples.

[0131] 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).

[0132] Comparative Example 1 - 2'-(bis(o-tolyloxy)methoxy)-[1,1'-di(cyclohexane)]-2-ylphosphite Synthesis of Nickel Complex Solution of Di-o-Tolyl Ester .

[0133] Comparative Example 2 - 2,2'-bis((bis(o-tolyloxy)phosphinoyl)oxy)-[1,1'-binaphthyl]-3,3'- Synthesis of Nickel Complex Solution of Diisopropyl Dicarboxylate .

[0134] Comparative Example 3 - Using 2'-(bis(o-tolyloxy)methoxy)-[1,1'-di(cyclohexane)]-phosphite Isomerization of 2-methyl-3-butenenitrile with nickel complex solution of 2-methyl-di-o-tolyl ester .

[0135] Comparative Example 4 - Using 2,2 ' -bis((bis(o-tolyloxy)phosphinoyl)oxy)-[1,1 ' -binaphthyl]-3, 3 ' Isomerization of 2-methyl-3-butenenitrile with nickel complex solution of diisopropyl dicarboxylate .

[0136] Comparative Example 5 - Using 2'-(bis(o-tolyloxy)methoxy)-[1,1'-di(cyclohexane)]-phosphite Hydrocyanation of 3PN with nickel complex solution of 2-di-o-tolyl ester .

[0137] Comparative Example 6 - Using 2,2'-bis((bis(o-tolyloxy)phosphinoyl)oxy)-[1,1'-binaphthyl]-3, Hydrocyanation of 3PN with nickel complex solution of diisopropyl 3'-dicarboxylate .

[0138] Experimental Example 1. Synthesis of the nickel complex of ligand A by the dissolved metal method .

[0139] In a glove box with an argon atmosphere, nickel metal powder (0.40 g), ligand A (1.00 g), zinc chloride (0.05 g), and 3-pentenenitrile (5.00 g) 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 24 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.

[0140] Experimental Example 2. Synthesis of the Nickel Complex of Ligand B by Dissolved Metal Method .

[0141] The procedure of Experimental Example 1 was repeated except that ligand B was used instead of ligand A.

[0142] Experimental Example 3. Synthesis of the Nickel Complex of Ligand C by the Dissolved Metal Method .

[0143] The procedure of Experimental Example 1 was repeated except that ligand C was used instead of ligand A.

[0144] Experimental Example 4. Synthesis of the Nickel Complex of Ligand D by Dissolved Metal Method .

[0145] The procedure of Experimental Example 1 was repeated except that ligand D was used instead of ligand A.

[0146] Comparative Example 1 - Synthesis2'-(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 Al, and the corresponding nickel complex was synthesized following the procedure of Experimental Example 1, but with Ligand A replacing CEx1.

[0147]

[0148] 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.

[0149]

[0150] Experimental Example 5. Preparation of 2-methyl-3-butenenitrile using the nickel complex solution prepared in Experimental Example 1 Isomerization .

[0151] 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 90°C and maintained at that temperature for 2.5 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 89%, and the selectivity to 3-pentenenitrile was 93%.

[0152] Experimental Example 6. Preparation of 2-methyl-3-butenenitrile using the nickel complex solution prepared in Experimental Example 2 Isomerization .

[0153] The procedure of Experimental Example 5 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 84%, and the selectivity to 3-pentenenitrile was 92%.

[0154] Experimental Example 7. Preparation of 2-methyl-3-butenenitrile using the nickel complex solution prepared in Experimental Example 3 Isomerization .

[0155] The procedure of Experimental Example 5 was repeated, except that the nickel complex of ligand C was substituted for the nickel complex of ligand A. The conversion of 2M3BN was determined to be 84%, and the selectivity to 3-pentenenitrile was 97%.

[0156] Experimental Example 8. Preparation of 2-methyl-3-butenenitrile using the nickel complex solution prepared in Experimental Example 4 Isomerization .

[0157] The procedure of Experimental Example 5 was repeated, except that the nickel complex of ligand A was replaced by the nickel complex of ligand D. The conversion of 2M3BN was determined to be 88%, and the selectivity to 3-pentenenitrile was 91%.

[0158] Comparative Example 3 - Isomerization of 2-methyl-3-butenenitrile (2M3BN) The procedure of Experimental Example 5 was followed using the nickel complex of CEx1, but the nickel complex of CEx1 was substituted for the nickel complex of Ligand A. The conversion of 2M3BN was determined to be 80%, and the selectivity to 3-pentenenitrile was 90%.

[0159] Comparative Example 4 - Isomerization of 2-methyl-3-butenenitrile (2M3BN) The procedure of Experimental Example 5 was followed using the nickel complex of CEx2, but the nickel complex of CEx2 was substituted for the nickel complex of Ligand A. The conversion of 2M3BN was determined to be 73%, and the selectivity to 3-pentenenitrile was 91%.

[0160] Experimental Example 9. Hydrocyanation of 3-pentenenitrile using the nickel complex solution prepared in Experimental Example 1 .

[0161] 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 89.4% and a DN distribution of 84.9%.

[0162] Experimental Example 10. Hydrocyanation of 3-pentenenitrile using the nickel complex solution prepared in Experimental Example 2 .

[0163] The procedure of Experimental Example 9 was repeated, but the nickel complex of ligand A was replaced by the nickel complex of ligand B. GC analysis of the resulting product mixture indicated an ADN yield of 73.3% and a DN distribution of 81.6%.

[0164] Experimental Example 11. Hydrocyanation of 3-pentenenitrile using the nickel complex solution prepared in Experimental Example 3 .

[0165] The procedure of Experimental Example 9 was repeated, except that the nickel complex of ligand C was substituted for the nickel complex of ligand A. GC analysis of the resulting product mixture indicated an ADN yield of 81.8% and a DN distribution of 77.0%.

[0166] Experimental Example 12. Hydrocyanation of 3-pentenenitrile using the nickel complex solution prepared in Experimental Example 4 .

[0167] The procedure of Experimental Example 9 was repeated, except that the nickel complex of ligand D 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 75.5%.

[0168] Comparative Example 5 - Hydrocyanation of 3-pentenenitrileThe procedure of Experimental Example 9 was followed using the nickel complex solution prepared from CEx1, but the nickel complex of ligand CEx1 was substituted 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%.

[0169] Comparative Example 6 - Hydrocyanation of 3-pentenenitrile The procedure of Experimental Example 9 was followed using the nickel complex solution prepared from CEx2, but the nickel complex of ligand CEx2 was substituted 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%.

[0170] 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 ligand containing arsenic and having formula (I): Where n is 2 and the ligand is bidentate; each X is O or NH; and Ar 1 and Ar 2 can be the same or different and are each an aryl group, provided that each Ar is attached to the same As atom 1 The groups can be combined to form a single aryl group.

2. The ligand of claim 1, wherein each X is O.

3. The ligand of claim 1, wherein each X is NH.

4. A ligand according to any preceding claim, wherein each Ar 1 Contains phenyl groups substituted with one or more alkyl groups having 1 to 4 carbon atoms.

5. The ligand of claim 4, wherein the one or more alkyl groups are independently selected from methyl and isopropyl.

6. The ligand according to claim 5, wherein each Ar 1 It is xylyl or 2-isopropyl-5-methylphenyl.

7. A ligand according to any preceding claim, wherein n is 2 and the ligand is bidentate, wherein the Ar 2 The groups are bonded to each other.

8. The ligand according to claim 7, wherein each Ar 2 The radical is an optionally substituted phenyl or naphthyl radical, wherein the phenyl rings or naphthyl rings are bonded to each other to form a biphenyl group or a binaphthyl group.

9. A ligand according to any preceding claim, wherein all X groups are O or all X groups are NH, n is 2 and the ligand is bidentate, wherein the Ar 2 The groups are bonded to each other to form a biphenyl group or a binaphthyl group, each of which can be optionally substituted with one or more substituents independently selected from an alkyl group having 1 to 6 carbon atoms and an alkoxy group having 1 to 6 carbon atoms.

10. The ligand according to claim 9, wherein the Ar 2 The groups are bonded to each other to form a biphenyl group, which can be optionally substituted with one or more substituents independently selected from alkyl groups having 1 to 6 carbon atoms and alkoxy groups having 1 to 6 carbon atoms.

11. The ligand according to claim 1, wherein the ligand has a structure according to formula (I) or formula (II): Wherein X is O or NH; Each R 1 independently selected from H and an alkyl group having 1 to 4 carbon atoms, or one R on each phenyl ring attached to the As atom 1 The group can be missing and replaced by a single bond connecting the two rings; Each R 2 Independently selected from H, alkyl groups having 1 to 6 carbon atoms, and alkoxy groups having 1 to 6 carbon atoms.

12. The ligand of claim 11, wherein all X groups are O or all X groups are NH.

13. The ligand according to claim 12, wherein each R 1 independently selected from H, methyl and isopropyl, or one R on each phenyl ring attached to the As atom 1 The group can be missing and replaced by a single bond connecting the two rings; and each R 2 Independently selected from H, alkyl groups having 1 to 4 carbon atoms, and alkoxy groups having 1 to 4 carbon atoms.

14. The ligand according to claim 1, comprising arsenic and having one of the following structures: and 。 15. A catalyst complex comprising a ligand according to any preceding claim and at least one transition metal.

16. The catalyst complex of claim 15, wherein the at least one transition metal comprises nickel.

17. 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 ligand containing arsenic and having formula (I): wherein n is 1 and the ligand is monodentate, or n is 2 and the ligand is bidentate; each X is O or NH; and Ar 1 and Ar 2 can be the same or different and are each an aryl group, provided that each Ar is attached to the same As atom 1 The groups can be combined to form a single aryl group.

18. The method of claim 17, wherein the organic compound comprises 1,3-butadiene.

19. The method of claim 17, wherein the organic compound comprises 3-pentenenitrile.

20. A process for the double bond isomerization of monoethylenically unsaturated compounds, wherein the compounds are contacted with a catalyst complex comprising at least one transition metal and a ligand containing arsenic and having the formula (I): wherein n is 1 and the ligand is monodentate, or n is 2 and the ligand is bidentate; each X is O or NH; and Ar 1 and Ar 2 can be the same or different and are each an aryl group, provided that each Ar is attached to the same As atom 1 The groups can be combined to form a single aryl group.

21. The method of claim 20, wherein the monoethylenically unsaturated organic compound comprises 2-methyl-3-butenenitrile.

22. A method according to any one of claims 17 to 21, wherein n is 2 and the ligand is bidentate.

23. The method according to any one of claims 17 to 22, wherein each X is O.

24. The method of any one of claims 17 to 22, wherein each X is NH.

25. The method according to any one of claims 17 to 24, wherein each Ar 1 Contains phenyl groups substituted with one or more alkyl groups having 1 to 4 carbon atoms.

26. The method of claim 25, wherein the one or more alkyl groups are independently selected from methyl and isopropyl.

27. The method of claim 26, wherein each Ar 1 It is xylyl or 2-isopropyl-5-methylphenyl.

28. The method of any one of claims 17 to 27, wherein n is 2 and the ligand is bidentate, wherein the Ar 2 The groups are bonded to each other.

29. The method of claim 28, wherein each Ar 2 The radical is an optionally substituted phenyl or naphthyl radical, wherein the phenyl rings or naphthyl rings are bonded to each other to form a biphenyl group or a binaphthyl group.

30. The method of any one of claims 17 to 29, wherein all X groups are O or all X groups are NH, n is 2 and the ligand is bidentate, wherein the Ar 2 The groups are bonded to each other to form a biphenyl group or a binaphthyl group, each of which can be optionally substituted with one or more substituents independently selected from an alkyl group having 1 to 6 carbon atoms and an alkoxy group having 1 to 6 carbon atoms.

31. The method of claim 30, wherein the Ar 2 The groups are bonded to each other to form a biphenyl group, which can be optionally substituted with one or more substituents independently selected from alkyl groups having 1 to 6 carbon atoms and alkoxy groups having 1 to 6 carbon atoms.

32. The method of any one of claims 17 to 22, wherein the ligand has a structure according to formula (I) or formula (II): Wherein X is O or NH; Each R 1 independently selected from H and an alkyl group having 1 to 4 carbon atoms, or one R on each phenyl ring attached to the As atom 1 The group can be missing and replaced by a single bond connecting the two rings; Each R 2 Independently selected from H, alkyl groups having 1 to 6 carbon atoms, and alkoxy groups having 1 to 6 carbon atoms.

33. The method of claim 32, wherein all X groups are O or all X groups are NH.

34. The method of claim 33, wherein each R 1 independently selected from H, methyl and isopropyl, or one R on each phenyl ring attached to the As atom 1 The group can be missing and replaced by a single bond connecting the two rings; and each R 2 Independently selected from H, alkyl groups having 1 to 4 carbon atoms, and alkoxy groups having 1 to 4 carbon atoms.

35. The method of any one of claims 17 to 22, wherein the ligand contains arsenic and has one of the following structures: and 。 36. The method of any one of claims 17 to 35, wherein the at least one transition metal comprises nickel.

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