Bidentate phosphite ligand / nickel catalyst and application thereof

Abstract

The invention provides a bidentate phosphite ligand / nickel catalyst and application thereof.The bidentate phosphite ligand / nickel catalyst is prepared from activated nickel powder and bidentate phosphite ligands through a coordination reaction, and the activated nickel powder is prepared through the steps that under the inert atmosphere condition, the bidentate phosphite ligands and the bidentate phosphite ligands are subjected to a coordination reaction, nickel metal powder with the particle size not larger than 20 microns reacts with excessive HCl gas to obtain the activated nickel powder, and the bidentate phosphite ligand comprises at least one of compounds shown in the structural formula I or II: # imgabs0 #. The bidentate phosphite ligand / nickel catalyst is easy to operate and low in cost; the process for preparing 3-PN through isomerization of 2M3BN catalyzed by the catalyst has the advantages of high reaction efficiency, high raw material conversion rate and high product selectivity, and is suitable for industrial large-scale application.

Description

Technical Field

[0001] The invention relates to the technical field of chemical synthesis, and in particular to a bidentate phosphite ligand / nickel catalyst and application thereof. Background Art

[0002] Adiponitrile (ADN) is an important organic chemical product, mainly used in the production of nylon 66. The current large-scale production process of ADN is mainly the butadiene hydrocyanation method, which has a short process, low energy consumption, high output and strong economic efficiency. It mainly includes the primary hydrocyanation, isomerization and secondary hydrocyanation reactions of butadiene and HCN under the action of a catalyst to obtain adiponitrile.

[0003] Among them, the products of the primary hydrocyanation reaction are mainly 3-pentenenitrile (3-PN) and 2-methyl-3-butenenitrile (2M3BN), as well as very small amounts of 2-methyl-2-butenenitrile, 2-pentenenitrile, methylglutaronitrile and other impurities. 2-Methyl-3-butenenitrile (2M3BN) is the main by-product of the primary hydrocyanation, and methylglutaronitrile will be further produced as a by-product in the secondary hydrocyanation process, making the overall process economically deteriorated. Therefore, in the process of butadiene hydrocyanation, it is necessary to consider isomerizing the branched 2-methyl-3-butenenitrile in the material after the primary hydrocyanation reaction into linear 3-pentenenitrile, so that it can be further converted into adiponitrile.

[0004] Patent US3536748 discloses that 2-methyl-3-butenenitrile is converted into linear pentenenitrile by contacting it with a nickel catalyst containing an alkyl or aryl phosphite at a temperature of 10-200°C. However, the reaction time of the patented technical solution is long, and the mass content of linear pentenenitrile in the material after the reaction is only 0.4-14%.

[0005] Patent US3676481 discloses a method for isomerizing 2-methyl-3-butenenitrile in the presence of zero-valent nickel, a phosphite ligand and a Lewis acid using trihydroxyboron as a co-catalyst. However, the long residence time during the isomerization process and the high thermal stress during the isomerization and subsequent distillation processes in this method easily lead to catalyst degradation.

[0006] Patents US5486643A and CN1052220C disclose a method for isomerizing 2-methyl-3-butenenitrile to linear pentenenitrile in aqueous solution using a sulfonated phosphine and a transition metal (preferably a nickel compound in a zero oxidation state). However, it should be noted that the presence of an aqueous solution in this method is very unfavorable for the subsequent secondary hydrocyanation reaction. In addition, the operation difficulty of removing trace amounts of water in the reaction system is also relatively high.

[0007] In addition, US Patents US5693843, 5821378, 5981772, 6020516, 6171997, 7345006, etc. all use nickel bis(1,5-cyclooctadiene) [Ni(COD)2] as a zero-valent nickel source to form a catalyst composition with a monodentate or multidentate phosphite ligand. Although under certain ligand structures, the catalyst system can achieve a good conversion of 2-methyl-3-butenenitrile to 3-pentenenitrile, the overall method is low in economic efficiency due to the high cost of Ni(COD)2, complex preparation process, and harsh storage conditions, and cannot be used in large-scale commercial production.

[0008] Patent US3847959 discloses a method for preparing a nickel catalyst complex by directly reacting commercially available nickel powder with an organic phosphite ligand. However, this method is only effective for monodentate phosphite ligands and lacks reaction activity and coordination difficulty for multidentate phosphite ligands.

[0009] Patent US8815186 discloses a method for preparing a nickel complex from nickel metal powder and bidentate phosphite. This method requires first preparing basic nickel carbonate, and then preparing highly reactive self-igniting nickel powder by a specific method. This method also has disadvantages such as easy sintering of nickel powder and carcinogenicity of basic nickel carbonate, so it still has certain limitations in large-scale commercial applications.

[0010] In summary, the optimization of the catalyst system is the key to the process of isomerizing 2-methyl-3-butenenitrile to 3-pentenenitrile. Faced with the growing demand for adiponitrile, how to develop a method for isomerizing 2-methyl-3-butenenitrile to 3-pentenenitrile that is simple to operate, low in cost, high in conversion rate, and suitable for large-scale production is an urgent problem to be solved. Summary of the invention

[0011] In view of the deficiencies in the prior art, the present invention discloses a bidentate phosphite ligand / nickel catalyst which has simple preparation method, low cost, high catalytic activity and catalytic efficiency, is suitable for industrial application, and its application in the isomerization of 2-methyl-3-butenenitrile to prepare 3-pentenenitrile.

[0012] In order to achieve the above technical objectives, on the one hand, the present invention provides a bidentate phosphite ligand / nickel catalyst, which is prepared by a coordination reaction between activated nickel powder and a bidentate phosphite ligand;

[0013] The preparation process of the activated nickel powder is as follows: under inert atmosphere conditions, nickel metal powder with a particle size not greater than 20 μm reacts with excess HCl gas to obtain the activated nickel powder;

[0014] The bidentate phosphite ligand comprises at least one of the compounds of formula I or II:

[0015]

[0016] Among them, R 1 and R 2 Each is independently selected from H, halogen, C1-C10 alkyl, alkoxy or alkylamino, substituted or unsubstituted aryl, or CO2R 11 , where R 11 is an aryl group or an alkyl group;

[0017] X 1 , X 2 , Y 1 , Y 2 Each independently selected from at least one of the compounds of structure III:

[0018]

[0019] Wherein, R 3 To R 7 Each is independently selected from H, halogen, C1-C10 alkyl, alkoxy or alkylamino, substituted or unsubstituted aryl, or CO2R 11 , where R 11 is an aryl group or an alkyl group;

[0020] Z 1 , Z 2 Each independently selected from at least one of the compounds of structure IV or V:

[0021]

[0022] Wherein, R in the compound of structure IV 8 To R 9 or R 10 Each is independently selected from H, halogen, C1-C10 alkyl, alkoxy or alkylamino, substituted or unsubstituted aryl and CO2R 11 , where R 11 is an aryl group or an alkyl group.

[0023] In the above technical scheme, ordinary commercially available nickel metal powder within a specific particle size range is used as a raw material, which not only avoids the use of complex nickel sources such as Ni(COD)2, anhydrous NiCl2, basic nickel carbonate, etc., and reduces the catalyst preparation cost. In the operation of the activated nickel powder, excess HCl reacts with the commercially available nickel powder to remove the oxide layer on the surface of the nickel powder, thereby improving the catalytic activity of the catalyst; further, in the above technical scheme, a bidentate phosphite ligand with a specific structure is used for direct coordination and complexation with the activated nickel powder. The steric effect and electronic effect of the bidentate phosphite ligand are more conducive to improving the stability and reaction activity of the bidentate phosphite ligand / nickel catalyst.

[0024] The examples and comparative examples of the present invention show the catalyst efficiency and selectivity of the bidentate phosphite ligand / nickel catalyst of the present invention in catalyzing the isomerization of 2M3BN.

[0025] In a further example of the present invention, the structure of the bidentate phosphite ligand is optimized. 3 To R 7 Each is independently preferably H, methyl, ethyl, isopropyl, tert-butyl or methoxy. 8 To R 9 Each is independently selected from H, methyl, ethyl, isopropyl, tert-butyl or methoxy. 10 is selected from H, methyl, ethyl, isopropyl, tert-butyl or methoxy.

[0026] In a further example of the present invention, during the preparation of the activated nickel powder, the molar ratio of the nickel metal powder to HCl gas is 1:(20-100), and the addition of excess HCl gas can promote the decomposition of the oxide layer and impurities on the surface of the nickel metal powder.

[0027] In a further example of the present invention, the control conditions of the preparation process of the activated nickel powder are explored and optimized. Optionally, the reaction temperature of the preparation process of the activated nickel powder is 120-200° C., preferably 150-180° C. Optionally, the reaction time of the preparation process of the activated nickel powder is 3-10 hours, preferably 5-7 hours.

[0028] The coordination reaction refers to the combination of atoms and ligands, and the atoms and ligands are coordinated through coordination bonds to form coordination compounds. In a further example of the present invention, the reaction conditions of the coordination reaction are explored and optimized.

[0029] Optionally, the coordination reaction is carried out in a first solvent; the first solvent includes at least one of toluene, cyclohexane, n-hexane, methylcyclohexane, benzene, xylene, tetrahydrofuran, and acetonitrile; and toluene may further be selected.

[0030] Optionally, the reaction temperature of the coordination reaction is 90-160°C, preferably 120°C-150°C, to promote the improvement of catalyst stability and selectivity.

[0031] Optionally, the coordination reaction is generally carried out under the condition of 0-0.5 MPa.

[0032] Optionally, the reaction time of the coordination reaction is 10-30 hours, which is conducive to the full complexation of nickel and ligand, thereby increasing the effective nickel content in the prepared catalyst and improving the catalytic activity.

[0033] In a further example of the present invention, the content of zero-valent nickel in the prepared bidentate phosphite ligand / nickel catalyst is 8000-15000 pppm, preferably 10000-13000 ppm.

[0034] It should be noted that the present invention does not limit the equipment used in the preparation process of activated nickel powder. Those skilled in the art can select reaction equipment that can provide inert atmosphere control conditions through non-creative labor; in addition, in order to promote the activation process, the preparation process of the activated nickel powder can be carried out under stirring conditions, and the nickel powder is fully contacted with excess HCl gas to improve the efficiency of nickel powder activation.

[0035] On the other hand, the present invention provides a method for preparing 3-pentenenitrile by isomerizing 2-methyl-3-butenenitrile. In this method, under the action of the above-mentioned bidentate phosphite ligand / nickel catalyst, 2-methyl-3-butenenitrile undergoes an isomerization reaction in a second solvent to obtain 3-pentenenitrile.

[0036] Furthermore, the molar ratio of the zero-valent nickel in the bidentate phosphite ligand / nickel catalyst to the 2-methyl-3-butenenitrile can be selected to be 1:(25-200). Controlling the molar ratio of the catalyst to the raw material improves the reaction efficiency and product selectivity, while optimizing the production cost and facilitating the optimization of control conditions.

[0037] Furthermore, the second organic solvent may be selected from at least one of nitriles, alkanes, and aromatic hydrocarbons; wherein the nitriles may be selected from at least one of pentenenitrile, acetonitrile, adiponitrile, methylglutaronitrile, 2-ethylsuccinonitrile, and benzonitrile; the alkanes may be selected from at least one of n-hexane, cyclohexane, pentane, methylcyclohexane, and decalin; the aromatic hydrocarbons may be selected from at least one of benzene, toluene, and xylene. Further preferably, the second solvent is pentenenitrile or toluene, and may be further selected from pentenenitrile; the above technical solution may be directly carried out in a system with the target product pentenenitrile as the second solvent, thereby reducing the difficulty of subsequent separation and purification and subsequent secondary hydrocyanation reaction.

[0038] Furthermore, the reaction temperature of the isomerization reaction can be selected to be 60-160° C., and further can be selected to be 80-130° C. Optionally, the time of the isomerization reaction is 0.5-4h. The preparation method of the present invention can shorten the isomerization reaction time and improve production efficiency.

[0039] It should be noted that the above isomerization reaction can be carried out under the condition of not adding or adding a Lewis acid auxiliary agent. The embodiment of the present invention shows the isomerization process and experimental results of 2M3BN with and without adding a Lewis acid auxiliary agent. As an optional embodiment, when a Lewis acid auxiliary agent is used, the Lewis acid auxiliary agent includes an inorganic or organic metal compound, and the metal includes at least one of scandium, titanium, vanadium, chromium, manganese, iron, cobalt, copper, zinc, boron, aluminum, yttrium, zirconium, niobium, molybdenum, cadmium, rhenium and tin. Further optionally, the Lewis acid is selected from ZnCl2, ZnBr2, ZnI2, ZnSO4, CuCl2, CuCl, Cu(O3SCF3)2, CoCl2, CoI2, FeI2, FeCl3, FeCl2, FeCl2(THF)2, TiCl4(THF)2, TiCl4, TiCl3, ClTi(OiPr)3, MnCl2, ScCl3, AlCl3, (C8H 17 )AlCl2,(C8H 17 )2AlCl, (i-C4H9)2AlCl, Ph2AlCl, PhAlCl2, ReCl5, ZrCl4, NbCl5, VCl3, CrCl2, MoCl5, YCl3, CdCl2, LaCl3, Er(O3SCF3)3, Yb(O2CCF3)3, SmCl3, B(C6H5)3, TaCl5, at least one of; further, it can be selected from at least one of ZnCl2, FeCl3, FeCl2.

[0040] Specifically, the amount of the Lewis acid is 0.2%-1.0wt% of the reaction system materials, wherein the reaction system materials refer to the sum of the materials added during the isomerization of 2-methyl-3-butenenitrile to prepare 3-pentenenitrile, including the reaction raw materials, the second solvent, the bidentate phosphite ligand / nickel catalyst and the auxiliary agent.

[0041] It should be noted that 2M3BN in the above technical scheme is one of the products of 1,3-butadiene and HCN after the primary hydrocyanation process in the reaction system for preparing adiponitrile from butadiene, and the material after the primary hydrocyanation reaction will be further input into the subsequent secondary hydrocyanation process for further reaction, so it is difficult to obtain pure 2M3BN material for isomerization reaction in the actual process. Generally speaking, the content of 2M3BN in the pentenenitrile mixture containing 2M3BN after the primary hydrocyanation reaction is about 80-99%, and the mixture is obtained by extracting and rectifying the material after the primary hydrocyanation reaction for multiple times, and also contains a small amount of cis / trans-2-methyl-2-butenenitrile, cis / trans-2-pentenenitrile and cis / trans-3-pentenenitrile, etc. The embodiments of the present invention and the comparative examples will use this pentenenitrile mixture containing 2M3BN as a raw material for isomerization reaction, and this operation is an operation that can be understood by technicians in the field.

[0042] It should be noted that the halogens described in the present invention refer to elements of Group VIIA of the periodic system, such as fluorine, chlorine, bromine, iodine, etc. The inert atmosphere described in the present invention refers to an atmosphere of a gas that does not chemically interact with the reactants, such as a nitrogen atmosphere, an argon atmosphere, and the like.

[0043] It should be noted that the present invention does not limit the equipment used for the isomerization reaction. Those skilled in the art can select reaction equipment that can provide inert atmosphere control conditions through non-creative labor, and the technical solutions thus formed are all within the protection scope of the present invention.

[0044] Compared with the prior art, the beneficial effects of the present invention are as follows: the bidentate phosphite ligand / nickel catalyst is obtained by complexing the activated nickel with a bidentate phosphite ligand of a specific structure, which is not only simple to operate and low in cost, but also has high reaction efficiency, high raw material conversion rate and high product selectivity in the process of preparing 3-PN by isomerization of 2M3BN catalyzed by the catalyst, and is suitable for large-scale industrial application. DETAILED DESCRIPTION

[0045] In order to facilitate the understanding of the present invention, the present invention will be described in more detail below, and preferred embodiments of the present invention are given. It should be noted that these embodiments of the present invention are only used for more detailed description and should not be understood as limiting the present invention in any form, that is, they are not intended to limit the scope of protection of the present invention.

[0046] Unless otherwise defined, the technical terms used in the following examples have the same meanings as those generally understood by those skilled in the art to which the present invention belongs. The test reagents used in the following examples, unless otherwise specified, are all conventional biochemical reagents; the experimental methods, unless otherwise specified, are all conventional methods.

[0047] It should be noted that in the description of the preferred embodiment, unless otherwise clearly specified and limited, the terms "first" and "second" are used for descriptive purposes only. For those skilled in the art, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances, and therefore they cannot be understood as limitations on the present invention.

[0048] Example 1

[0049] A bidentate phosphite ligand / nickel catalyst, which is prepared by the following method:

[0050] (1) Material preparation:

[0051] Activated nickel powder: 0.88 g of commercially available nickel powder was placed in a 100 mL reactor, replaced with N2 for multiple times, and about 20-30 g of HCl gas was introduced into the reactor; under vigorous stirring, the temperature was raised to 160°C and maintained for 5 hours; after the reaction, the HCl gas in the reactor was replaced with an inert gas to obtain activated nickel powder, the particle size of which was ≤20 μm.

[0052] Preparation of ligand A: In a nitrogen atmosphere, add 2-tert-butylphenol (15.02g, 0.1mol), PCl3 (6.87g, 50mmol) and 150mL of dry toluene to a 500mL round-bottom flask, cool the flask to -20°C, add triethylamine (31.2g, 0.31mol), react for 30min, add 100mL of toluene solution containing 7.16g (25mmol) of binaphthol, and then continue to react for 1h. The reaction mixture is filtered and washed with a small amount of toluene. After the filtrate is removed by rotary evaporation, it is further pumped dry with a vacuum oil pump to obtain ligand A as a white solid. The HPLC purity is 97.5%; 31 P NMR (162MHz, CDCl3): 128.90ppm; HPLC-MS measured [M+H]: 943.4262, theoretical molecular weight [M + H]:943.4256.

[0053] The structural formula of ligand A is as follows:

[0054]

[0055] It should be noted that the commercially available nickel powder mentioned in the embodiments of the present invention refers to nickel powder that can be purchased commercially, and its purity is generally not less than 99%.

[0056] It should be noted that the preparation process of the ligand in the embodiments of the present invention is only a preferred demonstration. Those skilled in the art can select other methods to prepare the ligand through non-creative labor, and under certain working conditions, they can directly purchase suitable types of ligands based on the technical solution of the present invention, and the protection scope of the present invention is not limited thereby.

[0057] (2) Coordination reaction: Ligand A (18.86 g, 20 mmol) was dissolved in 30 g of dry toluene and added to a 100 mL reactor containing active nickel powder (0.88 g, 15 mmol); heated to 120° C. and stirred for 24 h under an inert atmosphere. The reaction mixture was filtered in a nitrogen atmosphere to remove the unreacted nickel powder to obtain the bidentate phosphite ligand / nickel catalyst; ICP characterization showed that the effective nickel (0) content in the solution was 11745 ppm.

[0058] Example 2

[0059] A bidentate phosphite ligand / nickel catalyst, which is prepared by a coordination reaction between activated nickel powder and a bidentate phosphite ligand, specifically,

[0060] (1) Material preparation: The activated nickel powder used in this example is prepared in the same process as the activated nickel powder in Example 1; the preparation of ligand B in this example uses 2-isopropyl-5-methylphenol and binaphthol as raw materials, and the preparation process is the same as the preparation process of ligand A in Example 1, and the HPLC purity is 98.11%; 31 P NMR (162 MHz, CDCl3): 131.4 ppm; HPLC-MS measured [M+H]: 943.4245, theoretical calculated molecular weight [M+H]: 943.4251.

[0061] The structural formula of ligand B is as follows:

[0062]

[0063] (2) Coordination reaction: Ligand B (18.86 g, 20 mmol) was dissolved in 30 g of dry toluene and added to a 100 mL reactor containing active nickel powder (0.88 g, 15 mmol); heated to 130° C. and stirred for 24 h under an inert atmosphere. The reaction mixture was filtered in a nitrogen atmosphere to remove the unreacted nickel powder to obtain the bidentate phosphite ligand / nickel catalyst; ICP characterization showed that the effective nickel (0) content in the solution was 11631 ppm.

[0064] Example 3

[0065] A bidentate phosphite ligand / nickel catalyst, which is prepared by a coordination reaction between activated nickel powder and a bidentate phosphite ligand, specifically,

[0066] (1) Material preparation: The activated nickel powder used in this example is prepared in the same process as the activated nickel powder in Example 1; the preparation of ligand C in this example uses o-methylphenol and 3,3'-dimethoxybinaphthol as raw materials, and the preparation process is the same as the preparation process of ligand A in Example 1, and the HPLC purity is 96.59%; 31 P NMR (162 MHz, CDCl3): 130.1 ppm; HPLC-MS measured [M+H]: 835.2592, theoretical calculated molecular weight [M+H]: 835.2584.

[0067] The structural formula of ligand C is as follows:

[0068]

[0069] (2) Coordination reaction: Ligand C (16.70 g, 20 mmol) was dissolved in 30 g of dry toluene and added to a 100 mL reactor containing active nickel powder (0.88 g, 15 mmol); heated to 120° C. and stirred for 30 h under an inert atmosphere. The reaction mixture was filtered in a nitrogen atmosphere to remove the unreacted nickel powder to obtain the bidentate phosphite ligand / nickel catalyst; ICP characterization showed that the effective nickel (0) content in the solution was 12317 ppm.

[0070] Example 4

[0071] A bidentate phosphite ligand / nickel catalyst, which is prepared by a coordination reaction between activated nickel powder and a bidentate phosphite ligand, specifically,

[0072] (1) Material preparation: The activated nickel powder used in this example is prepared in the same manner as the activated nickel powder in Example 1; the ligand D in this example is prepared by the following method:

[0073] Under nitrogen atmosphere, 4,4`,6,6`-tetramethyl-2,2`-biphenyldiol (12.12 g, 50 mmol), PCl3 (6.87 g, 50 mmol) and 150 mL of dry toluene were added to a 500 mL round-bottom flask, the flask was cooled to -20°C, triethylamine (31.2 g, 0.31 mol) was added, and after reacting for 30 min, 100 mL of a toluene solution containing 7.16 g (25 mmol) of dinaphthol was added, and then the reaction was continued for 1 h; the mixture after the reaction was filtered and washed with a small amount of toluene, the filtrate was removed by rotary evaporation, and then the ligand D was obtained by continuous drying with a vacuum oil pump. The HPLC purity was 96.8%; 31 P NMR (162 MHz, CDCl3): 142.31 ppm; HPLC-MS measured [M+H]: 827.2687, theoretical calculated molecular weight [M+H]: 827.2691.

[0074] The structural formula of ligand D is as follows:

[0075]

[0076] (2) Coordination reaction: Ligand D (16.54 g, 20 mmol) was dissolved in 30 g of dry toluene and added to a 100 mL reactor containing active nickel powder (0.88 g, 15 mmol); heated to 140° C. and stirred for 24 h under an inert atmosphere. The reaction mixture was filtered in a nitrogen atmosphere to remove the unreacted nickel powder to obtain the bidentate phosphite ligand / nickel catalyst; ICP characterization showed that the effective nickel (0) content in the solution was 12443 ppm.

[0077] Example 5

[0078] A bidentate phosphite ligand / nickel catalyst, which is prepared by a coordination reaction between activated nickel powder and a bidentate phosphite ligand, specifically,

[0079] (1) Material preparation: The activated nickel powder used in this example is prepared in the same process as the activated nickel powder in Example 1; the preparation of ligand E in this example uses binaphthol and 3,3'-dimethylbinaphthol as raw materials, and the preparation process is the same as the preparation process of ligand D in Example 4, and the HPLC purity is 97.71%; 31 P NMR (162 MHz, CDCl3): 145.3 ppm; HPLC-MS measured [M+H]: 943.2377, theoretical calculated molecular weight [M+H]: 943.2377.

[0080] The structural formula of ligand E is as follows:

[0081]

[0082] (2) Coordination reaction: The ligand E (17.49 g, 20 mmol) was dissolved in 30 g of dry toluene and added to a 100 mL reactor containing active nickel powder (0.88 g, 15 mmol); heated to 150° C. and stirred for 26 h under an inert atmosphere. The reaction mixture was filtered in a nitrogen atmosphere to remove the unreacted nickel powder to obtain the bidentate phosphite ligand / nickel catalyst; ICP characterization showed that the effective nickel (0) content in the solution was 12080 ppm.

[0083] Comparative Example 1

[0084] A nickel / bidentate phosphite ligand catalyst is prepared by coordination reaction of common commercial nickel powder and ligand A. Specifically, common nickel powder (0.88 g, 15 mmol) and ligand A (18.86 g, 20 mmol) are placed in a 100 mL reactor, 30 g of dry toluene is added, and the mixture is heated to 120° C. and stirred for 24 hours under an inert gas atmosphere. The reaction mixture is filtered in a nitrogen atmosphere to remove unreacted nickel powder, so as to prepare the nickel / bidentate phosphite ligand catalyst. According to ICP characterization, the effective nickel (0) content in the solution is 972 ppm.

[0085] Comparative Example 2

[0086] A nickel / monodentate phosphite ligand catalyst is prepared by coordination reaction of the activated nickel powder prepared in Example 1 and a monodentate tris(2-ethylphenyl)phosphite ligand. Specifically, tris(2-ethylphenyl)phosphite (15.77 g, 40 mmol) is dissolved in 30 g of dry toluene and added into a 100 mL reactor containing active nickel powder (0.88 g, 15 mmol); heated to 110° C. and stirred for 30 h under an inert gas atmosphere; the reaction mixture is filtered in a nitrogen atmosphere to remove unreacted nickel powder, thereby preparing the nickel / bidentate phosphite ligand catalyst; and according to ICP characterization, the effective nickel (0) content in the solution is 12600 ppm.

[0087] Comparative Example 3

[0088] A nickel / bidentate phosphite ligand catalyst is prepared by reacting the activated nickel powder prepared in Example 1 with a ligand X having the following structure and having a better isomerization effect in US Pat. No. 5,693,843. Specifically, the ligand X (14.53 g, 20 mmol) is dissolved in 30 g of dry toluene and added into a 100 mL reactor containing active nickel powder (0.88 g, 15 mmol); the mixture is heated to 120° C. and stirred for 30 h under an inert atmosphere; the mixture after the reaction is filtered in a nitrogen atmosphere to remove the unreacted nickel powder, thereby preparing the bidentate phosphite ligand / nickel catalyst; and the effective nickel (0) content in the solution is 10966 ppm as characterized by ICP.

[0089]

[0090] Implementation of test case 1

[0091] A method for isomerizing 2-methyl-3-butenenitrile to prepare 3-pentenenitrile, wherein 2-methyl-3-butenenitrile is isomerized in a second solvent under the action of the bidentate phosphite ligand / nickel catalyst prepared in Example 1 to obtain 3-pentenenitrile, specifically:

[0092] 10 g of catalyst and 18.31 g of 2M3BN isomer mixture (with an effective 2M3BN content of 88.56%) were placed in an isomerization reactor, replaced with nitrogen several times, and the reaction system was heated to 125° C. As the reaction proceeded, samples were taken from the reactor at different times for analysis. The results are shown in Table 1.

[0093] Table 1

[0094] Reaction time / min 2M3BN / % Trans+Cis-3PN / % Conversion rate / % Selectivity% 30 42.11 45.88 52.45 97.85 60 17.33 70.56 80.43 98.46 90 2.12 86.14 97.61 99.16

[0095] Implementation of Test Example 2

[0096] A method for preparing 3-pentenenitrile by isomerizing 2-methyl-3-butenenitrile, wherein 2-methyl-3-butenenitrile is isomerized in a second solvent under the action of the bidentate phosphite ligand / nickel catalyst prepared in Example 2 to obtain 3-pentenenitrile, specifically:

[0097] 20 g of catalyst and 36.30 g of 2M3BN isomer mixture (with an effective 2M3BN content of 88.56%) were placed in an isomerization reactor, replaced with nitrogen several times, and the reaction system was heated to 120° C. As the reaction proceeded, samples were taken from the reactor at different times for analysis. The results are shown in Table 2.

[0098] Table 2

[0099] Reaction time / min 2M3BN / % Trans+Cis-3PN / % Conversion rate / % Selectivity% 30 45.32 42.06 48.83 96.28 60 22.57 65.97 74.51 99.32 90 3.33 84.79 96.24 98.98

[0100] Implementation of Test Case 3

[0101] A method for preparing 3-pentenenitrile by isomerizing 2-methyl-3-butenenitrile, wherein 2-methyl-3-butenenitrile is isomerized in a second solvent under the action of the bidentate phosphite ligand / nickel catalyst prepared in Example 3 to obtain 3-pentenenitrile, specifically:

[0102] 20 g of catalyst and 38.45 g of 2M3BN isomer mixture (with an effective 2M3BN content of 88.56%) were placed in an isomerization reactor, replaced with nitrogen several times, and the reaction system was heated to 130°C; as the reaction proceeded, samples were taken from the reactor at different times for analysis, and the results are shown in Table 3.

[0103] Table 3

[0104] Reaction time / min 2M3BN / % Trans+Cis-3PN / % Conversion rate / % Selectivity% 30 37.91 50.13 57.19 98.13 60 14.45 73.76 83.68 98.95 90 1.45 86.68 98.36 99.01

[0105] Implementation of Test Case 4

[0106] A method for preparing 3-pentenenitrile by isomerizing 2-methyl-3-butenenitrile, wherein 2-methyl-3-butenenitrile is isomerized in a second solvent under the action of the bidentate phosphite ligand / nickel catalyst prepared in Example 4 to obtain 3-pentenenitrile, specifically:

[0107] 15 g of catalyst and 29.13 g of 2M3BN isomer mixture (with an effective 2M3BN content of 88.56%) were placed in an isomerization reactor, replaced with nitrogen several times, and the reaction system was heated to 130° C. As the reaction proceeded, samples were taken from the reactor at different times for analysis. The results are shown in Table 4.

[0108] Table 4

[0109] Reaction time / min 2M3BN / % Trans+Cis-3PN / % Conversion rate / % Selectivity% 30 50.14 36.78 43.38 94.61 60 27.52 59.23 68.93 96.33 90 4.12 81.98 95.35 96.58

[0110] Implementation of Test Case 5

[0111] A method for preparing 3-pentenenitrile by isomerizing 2-methyl-3-butenenitrile, wherein 2-methyl-3-butenenitrile is isomerized in a second solvent under the action of the bidentate phosphite ligand / nickel catalyst prepared in Example 5 to obtain 3-pentenenitrile, specifically:

[0112] 10 g of catalyst and 18.85 g of 2M3BN isomer mixture (with an effective 2M3BN content of 88.56%) were placed in an isomerization reactor, replaced with nitrogen several times, and the reaction system was heated to 130°C; as the reaction proceeded, samples were taken from the reactor at different times for analysis, and the results are shown in Table 5.

[0113] Table 5

[0114]

[0115]

[0116] Implementation of Test Case 6

[0117] A method for preparing 3-pentenenitrile by isomerizing 2-methyl-3-butenenitrile. The catalyst, 2M3BN isomer mixture and reaction control conditions used in the method are the same as those in Test Example 1, except that the reaction temperature of the isomerization is controlled at about 80°C. As the reaction proceeds, samples are taken from the reactor at different times for analysis, and the results are shown in Table 6.

[0118] Table 6

[0119] Reaction time / min 2M3BN / % Trans+Cis-3PN / % Conversion rate / % Selectivity% 30 61.25 27.23 30.84 98.14 60 33.44 54.89 62.24 98.80 90 10.57 77.63 88.06 98.99

[0120] Implementation of Test Case 7

[0121] A method for preparing 3-pentenenitrile by isomerizing 2-methyl-3-butenenitrile, wherein the catalyst and reaction control conditions used in the method are the same as those in Example 2, except that the amount of the added 2M3BN isomer mixture is different, specifically:

[0122] 20 g of the catalyst prepared in Example 2 and 18.15 g of a 2M3BN isomer mixture (wherein the effective 2M3BN content is 88.56%) were placed in an isomerization reactor, and nitrogen was replaced several times. The reaction system was heated to 120° C. As the reaction proceeded, samples were taken from the reactor at different times for analysis. The results are shown in Table 7.

[0123] Table 7

[0124] Reaction time / min 2M3BN / % Trans+Cis-3PN / % Conversion rate / % Selectivity% 30 30.15 58.34 65.96 99.15 60 12.69 75.87 85.67 99.43 90 1.87 86.48 97.89 99.26

[0125] Implementation of Test Case 8

[0126] A method for preparing 3-pentenenitrile by isomerizing 2-methyl-3-butenenitrile, wherein the catalyst, 2M3BN isomer mixture and reaction control conditions used in the method are the same as those in Example 1, except that a Lewis acid auxiliary is used in the method, specifically:

[0127] 10 g of the catalyst prepared in Example 1 and 18.31 g of a 2M3BN isomer mixture (wherein the effective 2M3BN content is 88.56%) were placed in an isomerization reactor, 136 mg of anhydrous ZnCl2 was added, nitrogen was replaced several times, and the reaction system was heated to 125°C; as the reaction proceeded, samples were taken from the reactor at different times for analysis, and the results are shown in Table 8.

[0128] Table 8

[0129] Reaction time / min 2M3BN / % Trans+Cis-3PN / % Conversion rate / % Selectivity% 30 43.55 44.81 50.82 98.60 60 16.19 72.02 81.72 98.92 90 2.25 85.89 97.46 99.02

[0130] Comparative test example 1

[0131] A method for preparing 3-pentenenitrile by isomerizing 2-methyl-3-butenenitrile, specifically:

[0132] 10 g of the nickel / bidentate phosphite ligand catalyst prepared in Comparative Example 1 and 18.31 g of a 2M3BN isomer mixture (wherein the effective 2M3BN content is 88.56%) were placed in an isomerization reactor, and the nitrogen was replaced several times. The reaction system was heated to 125°C. As the reaction proceeded, samples were taken from the reactor at different times for analysis. The results are shown in Table 9.

[0133] Table 9

[0134] Reaction time / min 2M3BN / % Trans+Cis-3PN / % Conversion rate / % Selectivity% 30 81.62 7.14 7.84 96.70 60 77.33 11.53 12.68 98.85 90 74.18 14.63 16.24 98.76

[0135] By comparing and analyzing Table 1 and Table 9, it can be seen that under the same reaction time, the conversion rate of 2M3BN catalyzed by the bidentate phosphite ligand / nickel catalyst prepared by the activated nickel powder of the present invention is higher, which confirms that the active nickel powder used in the present invention can better coordinate and complex with the specific bidentate phosphite ligand, further significantly improving the rate and efficiency of the catalyzed isomerization reaction, which is more obvious in large-scale industrial production.

[0136] Comparative test example 2

[0137] A method for preparing 3-pentenenitrile by isomerizing 2-methyl-3-butenenitrile, specifically:

[0138] 20 g of the nickel / monodentate phosphite ligand catalyst prepared in Comparative Example 2 and 39.33 g of a 2M3BN isomer mixture (wherein the effective 2M3BN content is 88.56%) were placed in an isomerization reactor, and the nitrogen was replaced several times. The reaction system was heated to 125°C. As the reaction proceeded, samples were taken from the reactor at different times for analysis. The results are shown in Table 10.

[0139] Table 10

[0140] Reaction time / min 2M3BN / % Trans+Cis-3PN / % Conversion rate / % Selectivity% 30 61.14 26.07 30.96 93.51 60 38.97 47.23 56.00 94.38 90 25.25 60.26 71.49 94.50

[0141] By comparing and analyzing Table 1 and Table 10, it can be seen that compared with the traditional nickel catalyst system formed by monodentate ligand coordination complexation, under the same reaction time, the bidentate phosphite ligand / nickel catalyst of the present invention catalyzes the 2M3BN isomerization reaction. The raw material conversion rate is higher and the selectivity of 3-PN is also higher. In addition, the bidentate phosphite ligand / nickel catalyst of the present invention also significantly improves the reaction efficiency of the isomerization reaction and is more suitable for industrial production.

[0142] Comparative test example 3

[0143] US Pat. No. 5,693,843 proposes a bidentate ligand X with the following structural formula. In this patent, Ni(COD)2 is used as a nickel source, and a catalyst complex system formed by the ligand is subjected to a 2M3BN isomerization reaction experiment. The results are shown in Table 11.

[0144]

[0145] Table 11

[0146] Reaction time / h 2M3BN / % Trans+Cis-3PN / % 1 41.7 66.6 2 38.0 71.5

[0147] Comparative test example 4

[0148] A method for preparing 3-pentenenitrile by isomerizing 2-methyl-3-butenenitrile, specifically: 10g of the nickel / bidentate phosphite ligand catalyst prepared in Comparative Example 3 and 18.31g of a 2M3BN isomer mixture are placed in an isomerization reactor, nitrogen is replaced multiple times, and the reaction system is heated to 125°C; as the reaction proceeds, samples are taken from the reactor at different times for analysis, and the results are shown in Table 12.

[0149] Table 12

[0150] Reaction time / h 2M3BN / % Trans+Cis-3PN / % 1 40.3 68.0 2 37.6 71.9

[0151] By comparing and analyzing Table 11 and Table 12, it can be seen that, relative to the use of expensive, complex preparation process Ni (COD) 2 as a nickel source in U.S. Pat. No. 5,693,843, the same active effect can be obtained by using the activated nickel powder that is easy to obtain in the present invention. Further, by comparing and analyzing Table 1 and Table 11, it can be seen that, relative to the bidentate complex catalyst used in Comparative Example Test Example 3, at the same reaction time, the 3-PN content and 2M3BN conversion amount of the catalytic reaction of the bidentate phosphite ligand / nickel catalyst of the present invention are higher, which verifies that in the bidentate phosphite ligand / nickel catalyst of the present invention, the steric effect and electronic effect of the bidentate phosphite ligand are better, which is more conducive to improving the stability and reaction activity of the catalyst system.

[0152] It should be noted that the above contents are further detailed descriptions of the present invention in combination with specific implementation methods, and it cannot be determined that the specific implementation of the present invention is limited to these descriptions. For ordinary technicians in the technical field to which the present invention belongs, several simple improvements can be made without departing from the concept of the present invention, which should be regarded as falling within the scope of protection of the present invention.

Claims

1. A bidentate phosphite ligand / nickel catalyst, characterized in that: It is prepared by coordination reaction between activated nickel powder and bidentate phosphite ligand; The preparation process of the activated nickel powder is as follows: under inert atmosphere conditions, nickel metal powder with a particle size not greater than 20 μm reacts with excess HCl gas to obtain the activated nickel powder; The bidentate phosphite ligand comprises at least one of the compounds of formula I or II: Among them, R 1 and R 2 Each is independently selected from H, halogen, C1-C10 alkyl, alkoxy or alkylamino, substituted or unsubstituted aryl, or CO2R 11 , where R 11 is an aryl group or an alkyl group; X 1 , X 2 , Y 1 , Y 2 Each independently selected from at least one of the compounds of structure III: Wherein, R 3 To R 7 Each is independently selected from H, halogen, C1-C10 alkyl, alkoxy or alkylamino, substituted or unsubstituted aryl, or CO2R 11 , where R 11 is an aryl group or an alkyl group; Z 1 , Z 2 Each independently selected from at least one of the compounds of structure IV or V: Wherein, R in the compound of structure IV 8 To R 9 or R 10 Each is independently selected from H, halogen, C1-C10 alkyl, alkoxy or alkylamino, substituted or unsubstituted aryl and CO2R 11 , R 11 is an aryl group or an alkyl group.

2. The bidentate phosphite ligand / nickel catalyst according to claim 1, characterized in that In the compound of structure III, R 3 To R 7 Each is independently selected from H, methyl, ethyl, isopropyl, tert-butyl or methoxy; And / or, in the compound of structure IV, R 8 To R 9 Each is independently selected from H, methyl, ethyl, isopropyl, tert-butyl or methoxy; And / or, in the compound of structure V, R 10 is selected from H, methyl, ethyl, isopropyl, tert-butyl or methoxy.

3. The bidentate phosphite ligand / nickel catalyst according to claim 1, characterized in that During the preparation of the activated nickel powder, the molar ratio of the nickel metal powder to the HCl gas is 1:(20-100); And / or, the reaction temperature of the preparation process of the activated nickel powder is 120-200° C., preferably 150-180° C.; And / or, the reaction time of the preparation process of the activated nickel powder is 3-10 hours, preferably 5-7 hours.

4. The bidentate phosphite ligand / nickel catalyst according to claim 1, characterized in that The coordination reaction is carried out in a first solvent; the first solvent comprises at least one of toluene, cyclohexane, n-hexane, methylcyclohexane, benzene, xylene, tetrahydrofuran, and acetonitrile; Preferably, the first solvent is toluene; And / or, the reaction temperature of the coordination reaction is 90-160°C, preferably 120°C-150°C; And / or, the reaction time of the coordination reaction is 10-30h.

5. The bidentate phosphite ligand / nickel catalyst according to claim 1, characterized in that: The content of zero-valent nickel in the bidentate phosphite ligand / nickel catalyst is 8000-15000 pppm, preferably 10000-13000 ppm.

6. A method for preparing 3-pentenenitrile by isomerizing 2-methyl-3-butenenitrile, characterized in that: Under the action of the bidentate phosphite ligand / nickel catalyst described in any one of claims 1 to 5, 2-methyl-3-butenenitrile undergoes an isomerization reaction in a second solvent to obtain 3-pentenenitrile.

7. The method for preparing 3-pentenenitrile by isomerizing 2-methyl-3-butenenitrile according to claim 6, characterized in that: The molar ratio of the zero-valent nickel in the bidentate phosphite ligand / nickel catalyst to the 2-methyl-3-butenenitrile is 1: (25-200)。 8. The method for preparing 3-pentenenitrile by isomerizing 2-methyl-3-butenenitrile according to claim 6, characterized in that: The second organic solvent is selected from at least one of nitriles, alkanes, and aromatic hydrocarbons; Preferably, the nitriles include at least one of pentenenitrile, acetonitrile, adiponitrile, methylglutaronitrile, 2-ethylsuccinonitrile and benzonitrile; Preferably, the alkanes include at least one of n-hexane, cyclohexane, pentane, methylcyclohexane and decalin; Preferably, the aromatic hydrocarbons include at least one of benzene, toluene and xylene.

9. The method for preparing 3-pentenenitrile by isomerizing 2-methyl-3-butenenitrile according to claim 6, characterized in that: The reaction temperature of the isomerization reaction is 60-160°C, preferably 80-130°C; And / or, the isomerization reaction time is 0.5-4h.

10. The method for preparing 3-pentenenitrile by isomerizing 2-methyl-3-butenenitrile according to claim 6, characterized in that: The isomerization reaction is carried out with the participation of a Lewis acid auxiliary; Preferably, the Lewis acid comprises an inorganic or organic metal compound, and the metal comprises at least one of scandium, titanium, vanadium, chromium, manganese, iron, cobalt, copper, zinc, boron, aluminum, yttrium, zirconium, niobium, molybdenum, cadmium, rhenium and tin, preferably at least one of ZnCl2, FeCl3, FeCl2; Preferably, the amount of the Lewis acid used is 0.2%-1.0wt% of the reaction system materials.

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