Method for one-step synthesis of adiponitrile

Abstract

The present invention provides a method for one-step synthesis of adiponitrile. In the method, starting materials butadiene and hydrogen cyanide directly react under the action of a rare earth metal-mixed ligand catalyst and an auxiliary agent to produce adiponitrile, wherein the rare earth metal-mixed ligand catalyst comprises a rare earth metal, a monodentate phosphite ligand, and a multidentate phosphite ligand. According to the present invention, by using the rare earth metal as a catalyst, together with the monodentate phosphite ligand and the multidentate phosphite ligand, the rare earth metal-mixed ligand catalyst with high catalytic performance and high stability is formed, which, in combination with the auxiliary agent, efficiently catalyzes the simultaneous reaction of butadiene with two molecules of hydrogen cyanide to directly obtain adiponitrile. The method greatly simplifies the process flow of producing adiponitrile by using butadiene and hydrogen cyanide as starting materials, and features a high starting material conversion rate, high adiponitrile selectivity, and low operating costs, thus being suitable for large-scale industrial production.

Description

One-step synthesis method of adiponitrile TECHNICAL FIELD

[0001] The present application relates to the technical field of chemical synthesis, in particular to a one-step synthesis method of adiponitrile. BACKGROUND

[0002] Adiponitrile, also known as 1,4-dicyanobutane, is an organic compound with the chemical formula C6H8N2, and is one of the most important chemical raw materials for the production of nylon 66. Currently, the mainstream production method of adiponitrile in industry is the butadiene hydrocyanation method, which has high atom economy, short process route, high yield and low pollution. Specifically, the reaction of butadiene hydrocyanation method for preparing adiponitrile in industry mainly includes three stages: (1) butadiene and hydrocyanic acid (HCN) are reacted by one-step hydrocyanation under the action of a catalyst to generate 3-pentenenitrile (3PN), and 2-methyl-3-butenenitrile (2M3BN) is generated as a byproduct; (2) the byproduct 2M3BN is isomerized into 3PN under the action of a catalyst; (3) 3PN and HCN are subjected to two-step cyanohydration to obtain the product adiponitrile.

[0003] The above reaction process is relatively long, and additional operations such as recovery of butadiene, hydrocyanic acid and catalyst, and purification of 3PN and 2M3BN are required. In addition, the catalyst activity in industry is not high, which leads to low conversion rates of raw materials butadiene and 3PN, usually only about 70-80%, and low selectivity of one-step cyanation product 3PN and final product adiponitrile, usually about 60-80%. The above limitations reduce the production efficiency, and the overall production process is not only complex but also has high equipment investment and operating cost. Therefore, it is urgent to develop a new catalytic reaction system to accelerate the reaction rate and improve the selectivity of adiponitrile, thereby reducing the cost and improving the production efficiency.

[0004] Chinese patent CN103694136A discloses a one-step synthesis method of adiponitrile from butadiene, which uses zero-valent nickel catalyst, phosphorus-containing monodentate ligand and Lewis acid for cyanohydration, but the conversion rate and selectivity are only 50-60%, and the process optimization effect is not significant; Chinese patent CN114105817A uses 1-(diphenylphosphino)-2-(ethyl diphenylphosphino) ferrocene, zero-valent nickel and monodentate phosphine ligand for hydrocyanation, and the conversion rate and selectivity of the method are improved, but the synthesis of the ligand is complex and not suitable for industrial production; Chinese patent CN116120207A uses a chiral monodentate phosphine ligand to catalyze butadiene for preparing adiponitrile, and the synthesis of the ligand is also complex and not suitable for large-scale industrial production. SUMMARY

[0005] In view of the deficiencies in the prior art, the application discloses a one-step synthesis method of adiponitrile, which directly reacts butadiene and hydrocyanic acid to generate adiponitrile under the action of a specific rare earth metal mixed ligand catalyst and an auxiliary agent, greatly simplifies the process flow, has high raw material conversion rate and adiponitrile selectivity, and is suitable for industrial production.

[0006] In order to achieve the above technical purposes, the application provides a one-step synthesis method of adiponitrile, in which butadiene and hydrocyanic acid are directly reacted to generate adiponitrile under the action of a rare earth metal mixed ligand catalyst and an auxiliary agent.

[0007] In order to overcome the above technical problems, the research and development team of the application is committed to developing a method for efficiently generating adiponitrile from butadiene and hydrocyanic acid without a staged reaction through only one-step reaction. During the continuous development process, the research and development team realizes the key role of the catalyst system, and therefore specially researches and explores a catalyst, a ligand and an auxiliary agent system suitable for one-step method, and thus proposes the above technical scheme.

[0008] The rare earth catalyst used in the application can form a multi-complex structure due to its unique electronic structure. In the above technical scheme, the mixed ligand of the monodentate phosphite ligand and the polydentate phosphite ligand is coordinated with the rare earth metal, and the auxiliary agent is combined to catalyze the direct synthesis of adiponitrile from butadiene and hydrocyanic acid, so as to simplify the adiponitrile production process and improve the production efficiency. The reaction mechanism of the technical scheme of the application is as follows:

[0009] The technical scheme of the application activates the two double bonds of butadiene under the comprehensive action of the rare earth metal, the monodentate ligand, the polydentate ligand and the auxiliary agent. The monodentate phosphite ligand has a simpler molecular structure and higher activity than the polydentate phosphite ligand, and can be well combined with butadiene during the reaction process. The polydentate phosphite ligand has a symmetrical spatial structure and strong chelating ability with the catalyst metal, and therefore can well stabilize the metal catalyst. Under the action of the high-activity catalyst system of the application, the intermediate process of generating 3PN through one-step hydrocyanation reaction is avoided, and the isomerization process of 3PN is further avoided; butadiene and two molecules of hydrocyanic acid are simultaneously reacted to directly obtain adiponitrile, and only a small amount of methyl pentanenitrile is generated as a byproduct in the process. The method has good industrial prospects.

[0010] Further, the research and development team of the application explores the types of the rare earth metal catalyst. Optionally, the rare earth metal catalyst includes at least one of cerium, scandium, yttrium, lanthanum, praseodymium, neodymium and ytterbium, and preferably cerium. The embodiment and the comparative example of the application show the optimization process.

[0011] Further, the research team of the present application explored the types of the monodentate phosphite ligand. Optionally, the monodentate phosphite ligand comprises at least one of triphenyl phosphite, tribenzyl phosphite, tri-p-tolyl phosphite, tri-m-tolyl phosphite, tri-o-tolyl phosphite, tris(2,4-dimethylphenyl) phosphite, tris(3,5-dimethylphenyl) phosphite, tris(2,4-dimethoxyphenyl) phosphite, tris(2,4-diisopropylphenyl) phosphite, tris(2-diisopropyl-4-methylphenyl) phosphite, tris(2-diisopropyl-5-methylphenyl) phosphite, tris(2-diisopropyl-4-methoxyphenyl) phosphite, tris(2,4-di-tert-butylphenyl) phosphite, tris(2-phenylphenyl) phosphite, preferably tri-p-tolyl phosphite. The embodiments of the present application show the effects of different ligand combinations on catalytic reactions.

[0012] Further, the research team of the present application explored the types of the monodentate phosphite ligand. Optionally, the monodentate phosphite ligand comprises at least one of triphenyl phosphite, tribenzyl phosphite, tri-p-tolyl phosphite, tri-m-tolyl phosphite, tri-o-tolyl phosphite, tris(2,4-dimethylphenyl) phosphite, tris(3,5-dimethylphenyl) phosphite, tris(2,4-dimethoxyphenyl) phosphite, tris(2,4-diisopropylphenyl) phosphite, tris(2-diisopropyl-4-methylphenyl) phosphite, tris(2-diisopropyl-5-methylphenyl) phosphite, tris(2-diisopropyl-4-methoxyphenyl) phosphite, tris(2,4-di-tert-butylphenyl) phosphite, tris(2-phenylphenyl) phosphite, preferably tri-p-tolyl phosphite. The embodiments of the present application show the effects of different ligand combinations on catalytic reactions.

[0013] Further, the research team of the present application optimized the types of the auxiliary agent. Optionally, the auxiliary agent comprises at least one of zinc chloride, aluminum chloride, iron chloride, ferrous chloride, tin tetrachloride, preferably zinc chloride. The embodiments of the present application show the effects of different types of auxiliary agents on catalytic reactions.

[0014] Further, the research team of the present application explored and optimized the amount of the rare earth metal catalyst in the rare earth metal mixed ligand catalyst. Optionally, the molar ratio of the rare earth metal catalyst in the rare earth metal mixed ligand catalyst to the hydrocyanic acid is 1:(10-1000), preferably 1:(50-200), thereby achieving better comprehensive technical effects in terms of comprehensive process cost, raw material conversion rate and product selectivity.

[0015] It should be noted that in the specific implementation of the present application, the rare earth metal and the monodentate and polydentate phosphite ligand are first mixed and coordinated under an inert atmosphere to form a specific rare earth metal complex catalyst. Therefore, further, the preparation process of the rare earth metal mixed ligand catalyst is that the rare earth metal and the monodentate phosphite ligand and the polydentate phosphite ligand are subjected to a coordination reaction under an inert atmosphere at 80-120°C for not less than 24 hours to obtain a rare earth metal mixed ligand catalyst. The rare earth metal mixed ligand catalyst formed by the coordination reaction not only improves the stability of the rare earth metal mixed ligand catalyst, but also ensures that the catalyst is in full contact with the reaction raw materials and reacts, thereby improving the reaction efficiency and selectivity. Further, the coordination reaction of the rare earth metal catalyst with the monodentate phosphite ligand and the polydentate phosphite ligand is carried out under stirring conditions.

[0016] Further, the molar ratio of the total input molar amount of the monodentate phosphite ligand and the polydentate phosphite ligand to the input molar amount of the rare earth metal is (2-20):1, preferably (4-10):1; further, the input molar ratio of the monodentate phosphite ligand to the polydentate phosphite ligand is (1-20):1, preferably (1-10):1, thereby improving the catalytic performance of the catalyst and the stability of the rare earth metal complex catalyst, and promoting the improvement of process efficiency and the reduction of process cost.

[0017] Further, the research and development team of the present application explores the amount of the additive. Optionally, the molar ratio of the total input molar amount of the monodentate phosphite ligand and the polydentate phosphite ligand to the molar amount of the additive is (1-10000):1, further optionally (50-2000):1, and the reaction rate is improved and the yield is increased through the synergistic effect of the ligand and the additive.

[0018] Further, the present application also includes adding raw materials butadiene, hydrocyanic acid and the additive directly to the reaction system after the reaction of the rare earth metal, the monodentate phosphite ligand and the polydentate phosphite ligand to prepare the rare earth metal mixed ligand catalyst, and generating adiponitrile in one step.

[0019] It should be noted that in the present application, the inert gas refers to a gas that does not chemically interact with the reactants, for example: nitrogen and noble gas (such as argon) in the zero group of the periodic table.

[0020] Further, the reaction control conditions of the above reaction are optimized by the R&D team of the present application based on a large amount of experimental data. Optionally, the reaction temperature of the method is 20-200 DEG C, preferably 50-120 DEG C; optionally, the reaction pressure is 0.01-5 MPa, preferably 0.05-2 MPa, and the operability of the condition control of the technical scheme of the present application is strong; optionally, the reaction time is 0.5-20 h, preferably 2-10 h, and the production efficiency of the technical scheme of the present application is significantly improved compared with the existing technical scheme of the stage adiponitrile preparation process.

[0021] Compared with the prior art, the present application has the beneficial effects that: by taking rare earth metal as a catalyst, a high-catalytic-performance and high-stability rare earth metal mixed ligand catalyst is formed with a monodentate phosphite ligand and a polydentate phosphite ligand, and a high-efficiency catalyst is combined with an assistant to directly obtain adiponitrile by simultaneously reacting butadiene and two molecules of hydrocyanic acid. The method greatly simplifies the process flow of producing adiponitrile by taking butadiene and hydrocyanic acid as raw materials, has high raw material conversion rate and adiponitrile selectivity, has low operation cost, and is suitable for large-scale industrial production. BRIEF DESCRIPTION OF DRAWINGS

[0022] The accompanying drawings, which form a part of this application, are used to provide a further understanding of the application and are incorporated in and constitute a part of this application. The embodiments of the present application and its description are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0023] Fig. 1 shows the gas chromatogram of the reaction material after reaction in the embodiment 1 of the present application;

[0024] Fig. 2 shows the gas chromatogram of the reaction material after reaction in the comparative example 1.1 of the present application. DETAILED DESCRIPTION

[0025] In order to facilitate the understanding of the present application, the present application will be described more fully below with reference to the preferred embodiments of the present application. However, it should be understood that these embodiments are only used for more detailed description and should not be understood as limiting the present application in any form, i.e. not intended to limit the protection scope of the present application.

[0026] Unless otherwise defined, the technical terms used in the following examples have the same meaning as generally understood by those skilled in the art to which the present application belongs. The test reagents used in the following examples, unless otherwise specified, are conventional biochemical reagents; and the experimental methods, unless otherwise specified, are conventional methods.

[0027] It should be noted that the monodentate phosphite and the polydentate phosphite used in the embodiments of the present application can be obtained by commercial purchase or by the existing published technology.

[0028] It is to be noted that the rare earth metal catalyst in the embodiments of the present application is prepared by molten salt electrolysis, i.e. electrolysis in a molten salt of rare earth fluoride to precipitate the rare earth metal. The rare earth metal mixed ligand catalyst in the embodiments of the present application can be prepared by stirring the rare earth metal and the monodentate phosphite ligand and the polydentate phosphite ligand under a nitrogen atmosphere at a temperature of 80-120℃ for not less than 24 hours to form a specific rare earth metal mixed ligand catalyst for reaction. It is to be noted that the average coordination number of the rare earth metal in the rare earth metal mixed ligand catalyst is between 8 and 10, i.e. each rare earth metal element is coordinated with 8-10 monodentate phosphite ligands and polydentate phosphite ligands. The input amount of the monodentate phosphite ligand and the polydentate phosphite ligand determines the ratio of the number of monodentate phosphite ligands and polydentate phosphite ligands per metal in the catalyst, which is between 2:1 and 3:1. The ratio of the number of monodentate phosphite ligands and polydentate phosphite ligands per metal mainly affects the service life of the catalyst, and the present application aims to solve the technical problems of low conversion rate of hydrocyanic acid and poor selectivity of adiponitrile. Therefore, the ratio of the number of monodentate phosphite ligands and polydentate phosphite ligands per metal will not be described in the embodiments of the present application. However, the service life of the catalyst obtained based on the above ratio is good, and will not be described.

[0029] It is to be noted that the amount of butadiene is slightly excessive when feeding in the embodiments of the present application for safety reasons. Therefore, the conversion rate of hydrocyanic acid is used to calculate the subsequent technical effect.

[0030] The present application provides a one-step method for synthesizing adiponitrile. The raw material butadiene and hydrocyanic acid are directly reacted to generate adiponitrile under the action of a rare earth metal mixed ligand catalyst and an auxiliary agent. Specifically, the method comprises the following steps: (1) the rare earth metal catalyst is coordinated with the monodentate phosphite ligand and the polydentate phosphite ligand under an inert atmosphere to obtain a rare earth metal mixed ligand catalyst; and (2) the raw material butadiene and hydrocyanic acid are directly reacted to generate adiponitrile under the action of the rare earth metal mixed ligand catalyst and the auxiliary agent.

[0031] Example 1

[0032] A one-step method for synthesizing adiponitrile, specifically, first, 1 mol of cerium is added as a catalyst, 5 mol of tri-p-tolyl phosphite is added as a monodentate ligand, and 5 mol of 2,2'-binaphthol bis-diphenyl phosphite is added as a polydentate ligand in a 10 L stainless steel autoclave, and mixed under the condition of nitrogen blowing, the stirring temperature is 90°C, and the stirring time is not less than 24 h, to form a specific viscous rare earth metal mixed ligand catalyst; then 0.1 mol of zinc chloride is added as an additive, the autoclave is sealed, then replaced with nitrogen for more than five times, then 51 mol (2754 g) of dehydrated butadiene is added from the feeding port, the reaction kettle is heated to 80°C, and the pressure is increased to 0.7 MPa; then 100 mol (2700 g) of anhydrous hydrocyanic acid is continuously pumped in for 10 h by using a plunger pump, as the hydrocyanic acid is added, the butadiene in the reaction kettle is continuously consumed, causing the pressure in the reaction kettle to continuously decrease, when the hydrocyanic acid feeding is completed, the pressure in the reaction kettle decreases to 0.1 MPa, then the reaction is continued for 2 h at 80°C, and the pressure in the reaction kettle decreases to 0.01 MPa.

[0033] After cooling, the sample is taken, the content of hydrocyanic acid in the product is analyzed by titration method, and the conversion rate of hydrocyanic acid is calculated. The reaction product is a yellow clear liquid; quantitative analysis by gas chromatography (results as shown in Figure 1), the conversion rate of the material is based on the amount of hydrocyanic acid reaction divided by the initial amount of feed, and the selectivity of adiponitrile is based on the proportion of adiponitrile in the product, and the results are shown in Table 1.

[0034] It should be noted that in the post-treatment of the reaction liquid, first, the reaction liquid is purged with nitrogen to remove trace amounts of hydrocyanic acid in the reaction liquid to ensure safety; then 1 / 5 of the volume of the reaction liquid is added to the reaction liquid to extract and separate the catalyst, then the catalyst is obtained after the cyclohexane is removed for recycling; the adiponitrile phase is purified by rectification to obtain pure adiponitrile.

[0035] Comparative Example 1

[0036] This comparative example includes Comparative Example 1.1 and Comparative Example 1.2, the operation process and control conditions of this comparative example are the same as those of Example 1, the difference is that the catalysts used are nickel and cobalt respectively, the control conditions and reaction results are shown in Table 1, and the gas chromatography quantitative analysis results of Comparative Example 1.1 are shown in Figure 2.

[0037] Comparative Example 2

[0038] The operation process and control conditions of the present comparative examples are the same as those of Example 1, except that: in Comparative Example 2.1, only 5 mol of 2,2'-binaphthol bis-diphenyl phosphite is used as the polydentate phosphite ligand in step (1), and no monodentate phosphite ligand is added; in Comparative Example 2.2, only 5 mol of tri-p-cresyl phosphite is used as the monodentate phosphite ligand in step (1), and no polydentate phosphite ligand is added; and in Comparative Example 2.3, no ligand is added. The control conditions and reaction results are shown in Table 1.

[0039] Comparative Example 3

[0040] The operation process and control conditions of the present comparative examples are the same as those of Example 1, except that: in Comparative Example 2.1, only 5 mol of 2,2'-binaphthol bis-diphenyl phosphite is used as the polydentate phosphite ligand in step (1), and no monodentate phosphite ligand is added; in Comparative Example 2.2, only 5 mol of tri-p-cresyl phosphite is used as the monodentate phosphite ligand in step (1), and no polydentate phosphite ligand is added; and in Comparative Example 2.3, no ligand is added. The control conditions and reaction results are shown in Table 1.

[0041] Comparative Example 4

[0042] The operation process and control conditions of the present comparative examples are the same as those of Example 1, except that: in Comparative Example 2.1, only 5 mol of 2,2'-binaphthol bis-diphenyl phosphite is used as the polydentate phosphite ligand in step (1), and no monodentate phosphite ligand is added; in Comparative Example 2.2, only 5 mol of tri-p-cresyl phosphite is used as the monodentate phosphite ligand in step (1), and no polydentate phosphite ligand is added; and in Comparative Example 2.3, no ligand is added. The control conditions and reaction results are shown in Table 1.

[0043] Comparative Example 5

[0044] The operation process and control conditions of the present comparative examples are the same as those of Example 1, except that: in Comparative Example 2.1, only 5 mol of 2,2'-binaphthol bis-diphenyl phosphite is used as the polydentate phosphite ligand in step (1), and no monodentate phosphite ligand is added; in Comparative Example 2.2, only 5 mol of tri-p-cresyl phosphite is used as the monodentate phosphite ligand in step (1), and no polydentate phosphite ligand is added; and in Comparative Example 2.3, no ligand is added. The control conditions and reaction results are shown in Table 1.

[0045] Table 1

[0046] Example 2

[0047] Based on the one-step method for synthesizing adiponitrile shown in Example 1, the type of the rare earth catalyst is explored in this example. The operation process and control conditions of this example are the same as those of Example 1, except that the type of the rare earth catalyst is different. The control conditions and reaction results are shown in Table 2. The catalyst used in Example 2.7 includes 0.5 mol of cerium and 0.5 mol of scandium, the catalyst used in Example 2.8 includes 0.5 mol of yttrium and 0.5 mol of scandium, and the catalyst used in Example 2.9 includes 0.4 mol of cerium, 0.4 mol of scandium, and 0.2 mol of yttrium.

[0048] Table 2

[0049] As shown in Table 2, different rare earth metal catalysts can be used for the direct reaction of butadiene and hydrocyanic acid to obtain adiponitrile, and the results show that the conversion rate of hydrocyanic acid and the selectivity of adiponitrile are both high; the rare earth metal catalysts described in the present application can be selected from at least one of cerium, scandium, yttrium, lanthanum, praseodymium, neodymium and ytterbium, and further can be selected from cerium.

[0050] Example 3

[0051] Based on the method for synthesizing adiponitrile by one-step method shown in Example 1, the types of monodentate phosphite ligands and polydentate phosphite ligands are explored in the present embodiment 1. Specifically, the operation process and control conditions of the present embodiment are the same as those of Example 1, and the difference lies in the types of monodentate phosphite ligands and polydentate phosphite ligands used. The control conditions and reaction results are shown in Table 3.

[0052] Table 3

[0053] As shown in Table 3, the monodentate phosphite ligand in the technical scheme of the present application can be selected from at least one of triphenyl phosphite, tribenzyl phosphite, tri-p-tolyl phosphite, tri-m-tolyl phosphite, tri-o-tolyl phosphite, tris(2,4-dimethylphenyl) phosphite, tris(3,5-dimethylphenyl) phosphite, tris(2,4-dimethoxyphenyl) phosphite, tris(2,4-diisopropylphenyl) phosphite, tris(2-diisopropyl-4-methylphenyl) phosphite, tris(2-diisopropyl-5-methylphenyl) phosphite, tris(2-diisopropyl-4-methoxyphenyl) phosphite, tris(2,4-di-tert-butylphenyl) phosphite and tris(2-phenylphenyl) phosphite, and further can be selected from tri-p-tolyl phosphite; the polydentate phosphite ligand can be selected from at least one of 2,2'-diphenylol phosphite dibenzyl phosphite, 2,2'-diphenylol phosphite dibenzyl phosphite, 2,2'-diphenylol phosphite dimethyl phosphite, 2,2'-diphenylol phosphite dimethyl phosphite, 2,2'-diphenylol phosphite di(2,2'-diphenylol) phosphite, 3,3',5,5'-tetra-tert-butyl-2,2'-diphenylol phosphite di(2,2'-diphenylol) phosphite, 3,3',5,5'-tetra-methyl-2,2'-diphenylol phosphite di(2,2'-diphenylol) phosphite, 3,3',5,5'-tetra-methoxy-2,2'-diphenylol phosphite di(2,2'-diphenylol) phosphite and 3,3'-di-tert-butyl-5,5'-dimethoxy-2,2'-diphenylol phosphite di(2,2'-diphenylol) phosphite, and further can be selected from 2,2'-dinaphthylol phosphite dibenzyl phosphite. Different types of monodentate and polydentate phosphite mixed ligands can be used for the direct reaction of butadiene and hydrocyanic acid to obtain adiponitrile, and the conversion rate of hydrocyanic acid and the selectivity of adiponitrile are both high.

[0054] Example 4

[0055] Based on the method for synthesizing adiponitrile in one step shown in Example 1, the type of the auxiliary agent is explored in this example. Specifically, the operation process and control conditions of this example are the same as those of Example 1, except for the type of the auxiliary agent. The control conditions and reaction results are shown in Table 4.

[0056] Table 4

[0057] As can be verified from Table 4, the auxiliary agent in the technical solution of the present application includes at least one of Lewis acids zinc chloride, aluminum chloride, iron chloride, ferrous chloride, and tin tetrachloride, preferably zinc chloride, which can assist in catalyzing the direct reaction of butadiene with hydrocyanic acid to obtain adiponitrile, and the conversion rate of hydrocyanic acid and the selectivity of adiponitrile of the reaction are both high.

[0058] Example 5

[0059] A method for synthesizing adiponitrile in one step, specifically, 1 mol of cerium is added as a catalyst, 10 mol of tri-p-tolyl phosphite is added as a monodentate ligand, and 1 mol of 2,2'-binaphthol bis-diphenyl phosphite is added as a polydentate ligand in a 10 L stainless steel autoclave, which are mixed under the condition of nitrogen purging with mechanical stirring, the stirring temperature is 90°C, and the stirring time is not less than 24 h, to form a specific viscous rare earth metal mixed ligand catalyst; then 0.01 mol of zinc chloride is added as an auxiliary agent, the autoclave is sealed, and then purged with nitrogen for more than five times, and then 51 mol (2754 g) of dehydrated butadiene is added from the feeding port, and the reaction kettle is heated to 120°C; then 100 mol (2700 g) of anhydrous hydrocyanic acid is continuously pumped in for 10 h using a plunger pump, the pressure of the reaction kettle is 0.3 MPa, and then the reaction is continued at 120°C for 2 h; after the reaction, gas chromatography is used for quantitative analysis, the conversion rate of hydrocyanic acid is 97.9%, the selectivity of adiponitrile is 97.5%, and the selectivity of methyl glutaronitrile is 2.4%.

[0060] Example 6

[0061] A one-step method for synthesizing adiponitrile, specifically, 1 mol of cerium is added as a catalyst, 10 mol of tri-p-tolyl phosphite is used as a monodentate ligand, and 2 mol of 2,2'-binaphthol bis-diphenyl phosphite is used as a polydentate ligand in a 10 L stainless steel autoclave, and mixed under the condition of nitrogen purging using mechanical stirring, the stirring temperature is 90℃, and the stirring time is not less than 24 h, to form a specific viscous rare earth metal mixed ligand catalyst; then 0.05 mol of zinc chloride is added as an additive, the autoclave is sealed, and then replaced with nitrogen for more than five times, and then 51 mol (2754 g) of dehydrated butadiene is added from the feeding port, and the reaction kettle is heated to 50℃; then 100 mol (2700 g) of anhydrous hydrocyanic acid is continuously pumped in for 10 h using a plunger pump, the pressure of the reaction kettle is 0.05 MPa, and then the reaction is continued at 50℃ for 3 h; after the reaction, quantitative analysis is performed using gas chromatography, the conversion rate of hydrocyanic acid is 97.3%, the selectivity of adiponitrile is 97.2%, and the selectivity of methyl pentanenitrile is 2.5%.

[0062] Example 7

[0063] A one-step method for synthesizing adiponitrile, specifically, 1 mol of cerium is added as a catalyst, 10 mol of tri-p-tolyl phosphite is used as a monodentate ligand, and 2 mol of 2,2'-binaphthol bis-diphenyl phosphite is used as a polydentate ligand in a 10 L stainless steel autoclave, and mixed under the condition of nitrogen purging using mechanical stirring, the stirring temperature is 90℃, and the stirring time is not less than 24 h, to form a specific viscous rare earth metal mixed ligand catalyst; then 0.05 mol of zinc chloride is added as an additive, the autoclave is sealed, and then replaced with nitrogen for more than five times, and then 51 mol (2754 g) of dehydrated butadiene is added from the feeding port, and the reaction kettle is heated to 50℃; then 100 mol (2700 g) of anhydrous hydrocyanic acid is continuously pumped in for 10 h using a plunger pump, the pressure of the reaction kettle is 0.05 MPa, and then the reaction is continued at 50℃ for 3 h; after the reaction, quantitative analysis is performed using gas chromatography, the conversion rate of hydrocyanic acid is 97.3%, the selectivity of adiponitrile is 97.2%, and the selectivity of methyl pentanenitrile is 2.5%.

[0064] From the results of the above examples, it can be seen that butadiene and hydrocyanic acid can be directly reacted to obtain adiponitrile under different raw material ratios and reaction conditions, and the conversion rate of hydrocyanic acid and the selectivity of adiponitrile are both high.

[0065] It should be noted that the above content is a further detailed description of the present application in combination with specific embodiments, and the specific implementation of the present application cannot be limited to these descriptions; the size data of the present embodiment does not limit the technical solution, but only demonstrates one specific working condition. For ordinary skilled persons in the technical field to which the present application belongs, without departing from the concept of the present application, a number of simple improvements and refinements can be made, which should be considered as falling within the scope of protection of the present application.

Claims

1. A process for the one-step synthesis of adiponitrile, characterized in that, Raw material butadiene and hydrocyanic acid are directly reacted to generate adiponitrile under the action of a rare earth metal mixed ligand catalyst and an auxiliary agent; the rare earth metal mixed ligand catalyst comprises a rare earth metal, a monodentate phosphite ligand and a polydentate phosphite ligand.

2. The process for the synthesis of adiponitrile in one step according to claim 1, characterized in that, The rare earth metal comprises at least one of cerium, scandium, yttrium, lanthanum, praseodymium, neodymium and ytterbium, and preferably is cerium.

3. The process for the synthesis of adiponitrile in one step according to claim 1, characterized in that, The monodentate phosphite ligand comprises at least one of triphenyl phosphite, tribenzyl phosphite, tri-p-tolyl phosphite, tri-m-tolyl phosphite, tri-o-tolyl phosphite, tris(2,4-dimethylphenyl) phosphite, tris(3,5-dimethylphenyl) phosphite, tris(2,4-dimethoxyphenyl) phosphite, tris(2,4-diisopropylphenyl) phosphite, tris(2-diisopropyl-4-methylphenyl) phosphite, tris(2-diisopropyl-5-methylphenyl) phosphite, tris(2-diisopropyl-4-methoxyphenyl) phosphite, tris(2,4-di-tert-butylphenyl) phosphite and tris(2-phenylphenyl) phosphite, and preferably is tri-p-tolyl phosphite.

4. The process for the synthesis of adiponitrile in one step according to claim 1, characterized in that, The polydentate phosphite ligand comprises at least one of 2,2'-diphenylolphosphine bisdiphenyl phosphite, 2,2'-diphenylolphosphine bisdibenzyl phosphite, 2,2'-dinaphthylolphosphine bisdiphenyl phosphite, 2,2'-diphenylolphosphine bisdibenzyl phosphite, 2,2'-diphenylolphosphine bisditolyl phosphite, 2,2'-diphenylolphosphine bisditolyl phosphite, 2,2'-diphenylolphosphine bis(2,2'-diphenylolphosphine) phosphite, 3,3',5,5'-tetra-tert-butyl-2,2'-diphenylolphosphine bis(2,2'-diphenylolphosphine) phosphite, 3,3',5,5'-tetra-methyl-2,2'-diphenylolphosphine bis(2,2'-diphenylolphosphine) phosphite, 3,3',5,5'-tetra-methoxy-2,2'-diphenylolphosphine bis(2,2'-diphenylolphosphine) phosphite and 3,3'-di-tert-butyl-5,5'-di-methoxy-2,2'-diphenylolphosphine bis(2,2'-diphenylolphosphine) phosphite, and preferably is 2,2'-dinaphthylolphosphine bisdiphenyl phosphite.

5. The process for the synthesis of adiponitrile in one step according to claim 1, characterized in that, The auxiliary agent comprises at least one of zinc chloride, aluminum chloride, iron chloride, ferrous chloride and tin tetrachloride, and preferably is zinc chloride.

6. The process for the step synthesis of adiponitrile according to claim 1, characterized in that, The molar ratio of the rare earth metal in the rare earth metal mixed ligand catalyst to the hydrocyanic acid is 1:(10-1000), and preferably is 1:(50-200).

7. The process for the synthesis of adiponitrile in one step according to claim 1, characterized in that, The preparation process of the rare earth metal mixed ligand catalyst is that, under an inert atmosphere, the rare earth metal is subjected to a coordination reaction with the monodentate phosphite ligand and the polydentate phosphite ligand at 80-120°C for not less than 24 hours to obtain the rare earth metal mixed ligand catalyst. Preferably, the molar ratio of the total input molar amount of the monodentate phosphite ligand and the polydentate phosphite ligand to the input molar amount of the rare earth metal is (2-20):1, and preferably is (4-10):

1. Preferably, the molar ratio of the monodentate phosphite ligand to the polydentate phosphite ligand is (1-20):1, and preferably is (1-10):

1.

8. The process for the synthesis of adiponitrile in one step according to claim 1, characterized in that, The molar ratio of the total input molar amount of the monodentate phosphite ligand and the polydentate phosphite ligand to the molar amount of the auxiliary agent is (1-10000):1, preferably (50-2000):

1.

9. The process for the synthesis of adiponitrile in one step according to claim 1, characterized in that, After the reaction for preparing the rare earth metal mixed ligand catalyst from the rare earth metal, the monodentate phosphite ligand and the polydentate phosphite ligand is completed, the raw material butadiene, hydrocyanic acid and the auxiliary agent are directly added into the reaction system to generate adiponitrile in one step.

10. The process for the synthesis of adiponitrile in one step according to claim 1, characterized in that, The reaction temperature of the method is 20-200°C, preferably 50-120°C; Preferably, the reaction pressure is 0.01-5MPa, preferably 0.05-2MPa; Preferably, the reaction time is 0.5-20h, preferably 2-10h.

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