Amino-modified supported catalyst as well as preparation method and application thereof

Abstract

The invention provides an amino-modified supported catalyst as well as a preparation method and application thereof, and belongs to the technical field of catalyst preparation. Comprising the following steps: (1) roasting a pure silicon mesoporous molecular sieve, and pretreating with an alkali source to obtain a pure silicon mesoporous molecular sieve suspension; (2) adding an amino modifier and a binder into the pure silicon mesoporous molecular sieve suspension, and performing aging, alcohol removal, shearing and spray granulation to obtain a granular catalyst; and (3) carrying out solvent heat treatment on the granular catalyst, and carrying out vacuum drying to obtain the amino-modified supported catalyst. According to the amino-modified supported catalyst, oligomerization caused by acid sites is avoided, side reactions are reduced, and the isomerization reaction is more efficient; when the catalyst is applied to the process of producing adiponitrile by a butadiene method, the utilization rate of raw materials is higher, three wastes are reduced, and the production efficiency of the process of producing adiponitrile by the butadiene method is further improved.

Description

Technical Field

[0001] The present invention relates to the technical field of catalyst preparation, and particularly relates to an amino-modified supported catalyst, a preparation method thereof, and an application thereof. Background Art

[0002] The process for producing adiponitrile by the butadiene method includes steps such as the one-step hydrocyanation of butadiene, carbon chain isomerization, and the two-step hydrocyanation of butadiene. In the process of the one-step hydrocyanation of butadiene, an addition reaction occurs between one double bond of butadiene and hydrocyanic acid to generate pentenenitrile. Under certain reaction conditions, a large amount of 4-pentenenitrile is generated, as well as a part of 3-pentenenitrile and 2-pentenenitrile. Among them, 4-pentenenitrile can directly undergo two-step hydrocyanation to generate adiponitrile and methylglutaronitrile; 3-pentenenitrile can be converted into 4-pentenenitrile and then undergo two-step hydrocyanation to generate adiponitrile and methylglutaronitrile; only 2-pentenenitrile cannot undergo relevant hydrocyanation reactions and needs to be separated and removed from the adiponitrile production reaction system. However, the separation and removal not only cause waste of 2-pentenenitrile that can be used as a reaction raw material, but also bring a large amount of nitrogen-containing waste gas, waste liquid, and waste residue, thus polluting the environment. Therefore, it is very necessary to convert 2-pentenenitrile into 3-pentenenitrile and 4-pentenenitrile to improve the raw material utilization rate and the adiponitrile yield.

[0003] In the prior art, potassium tert-butoxide / tert-butanol solution is used to catalyze the conversion of 2-pentenenitrile into 3-pentenenitrile (Czechlslovak Chemical Communications, 1970, 35, 1224-1234). However, this reaction has a long reaction time, low conversion rate, high yield of trans-2-pentenenitrile, and an increase in oligomers, which is not conducive to industrial application.

[0004] Patent US3526654 uses inorganic substances such as silica / alumina / sodium calcium silicate as catalysts to convert cis-2-pentenenitrile into trans-3-pentenenitrile. Its conversion rate is low, and the isomerization reaction time is long. By increasing the temperature, the time can be reduced, but the amount of oligomers generated increases, and the catalyst is easily deactivated.

[0005] Patent US20060194979A1 uses alumina as a catalyst to catalyze the conversion of cis-2-pentenenitrile into trans-3-pentenenitrile. It is reported that the specific surface area of alumina should not be too large or too small, and the optimal value is 50-300m 2 / g. A too small specific surface area cannot catalyze the isomerization reaction, while a too large specific surface area will lead to the generation of oligomers. When the specific surface area reaches 250m 2 / g, the yield of 3-pentenenitrile is close to 20%, but the oligomers also reach 0.84%.

[0006] BASF mentions a method for isomerizing pentenenitrile in a reaction material stream in patents CN100567258C and US20070287851A1, where the isomerization is carried out on a homogeneously dissolved catalyst. The catalyst is an organic amine, and this system is a homogeneous catalytic system, still requiring a subsequent separation process.

[0007] Therefore, developing an efficient catalyst for converting 2-pentenenitrile into 3-pentenenitrile and 4-pentenenitrile can, on the one hand, solve the problem of raw material waste and increase the yield of adiponitrile, and on the other hand, also reduce the pressure of treating nitrogen-containing waste generated from the separation and removal of 2-pentenenitrile in the adiponitrile production reaction system, saving raw materials and reducing costs. Summary of the Invention

[0008] To solve the above technical problems, the present invention provides a preparation method and application of an amino-modified supported catalyst.

[0009] On the one hand, the present invention provides a preparation method of an amino-modified supported catalyst, comprising the following steps:

[0010] Step (1): Roast the pure silica mesoporous molecular sieve and then pretreat it with an alkali source to obtain a pure silica mesoporous molecular sieve suspension;

[0011] Step (2): Add an amino modifier and a binder to the pure silica mesoporous molecular sieve suspension, and obtain a granular catalyst after aging, alcohol removal, shearing, and spray granulation;

[0012] Step (3): Subject the granular catalyst to solvothermal treatment and then vacuum dry it to obtain the amino-modified supported catalyst.

[0013] Specifically,

[0014] Step (1): Roast the pure silica mesoporous molecular sieve at 400 - 800 °C, and then carry out pretreatment with an alkali source. The temperature of the alkali source pretreatment is (20 - 200) °C, and the treatment time is (1 - 24) h to obtain a pure silica mesoporous molecular sieve suspension.

[0015] Step (2): After adding an amino modifier and a binder to the pure silica mesoporous molecular sieve suspension obtained in Step (1), age it in a crystallization kettle or pressure bomb with a Teflon liner. The aging temperature is 50 - 150 °C, and the aging time is 1 - 24 h; after aging, evaporate the alcohols generated during the hydrolysis of the amino modifier and the organosilicate binder in the synthesis process at 80 - 120 °C, including methanol (derived from the hydrolysis of methoxysilane) and / or ethanol (derived from the hydrolysis of ethoxysilane); shear it evenly with a shear machine, and then carry out spray granulation at 100 - 220 °C.

[0016] After the pure silica mesoporous molecular sieve suspension is amino-modified and defatted, it is directly spray granulated under the action of a binder to obtain a catalyst with good particle size. This catalyst has a larger particle volume and higher strength, which is more conducive to solid-liquid separation and prevents a large amount of fine powder from running into the subsequent filter and clogging the filter pores.

[0017] Step (3): The granular catalyst obtained in step (2) and a solvent (anhydrous methanol, anhydrous ethanol, dichloromethane, acetone, etc.) are refluxed at 50-100 °C for 1-6 h according to the mass ratio of granular catalyst: solvent of 1: (1-10).

[0018] This process is to remove the quaternary ammonium cations in the pores of the mesoporous molecular sieve during the modification process. It should be noted that if the base source used in the alkali treatment process is an inorganic base, there are no large quaternary ammonium cations in its pores, so step (3) can be omitted, and the catalyst after spray granulation in step (2) can be used directly.

[0019] In the prior art, alumina is used as a catalyst for the conversion of 2-pentenenitrile to 3-pentenenitrile and 4-pentenenitrile. Based on this, the research team of the present invention found through a large number of experimental studies that when the specific surface area of alumina is too large, there are abundant acidic sites on the surface of its pores, while the number of acidic sites of alumina materials with a smaller specific surface area is significantly reduced. It is speculated that too many acidic sites will lead to side reactions - the polymerization reaction of pentenenitrile. In contrast, the surface acidity of pure silica molecular sieve is much weaker than that of alumina. If pure silica mesoporous molecular sieve is used as a catalyst, the occurrence of side reactions can be reduced. Further, the pore diameter of pure silica mesoporous molecular sieve is larger, which can enable the reactants to quickly diffuse to the active center to react; at the same time, its amorphous pore wall structure is also easier to modify.

[0020] At the same time, active components are required during the conversion of 2-pentenenitrile to 3-pentenenitrile and 4-pentenenitrile. In the prior art, organic amines can catalyze the conversion of 2-pentenenitrile to 3-pentenenitrile, and its catalytic activity mainly comes from the amino group. Therefore, the research and development team of the present invention prepared a heterogeneous catalyst by introducing the active component amino group loaded on the pure silica mesoporous molecular sieve. Compared with the homogeneous catalyst system of organic amines, it is easier to separate the catalyst from the reaction system.

[0021] In order to further enhance the conversion of 2-pentenenitrile to 3-pentenenitrile and 4-pentenenitrile, the research and development team of the present invention added a binder that can hydrolyze to form a Si-OH structure, which forms a Si-O-Si structure with the Si-OH structure in the pure silica mesoporous molecular sieve particles, thereby bonding different small pure silica mesoporous molecular sieve particles together, which helps spray granulation to form spherical particles with higher strength.

[0022] The R & D team of the present invention unexpectedly found through a large number of experiments that when the pure silica mesoporous molecular sieve is pretreated with an alkali source after calcination, the conversion of 2-pentenenitrile to 3-pentenenitrile and 4-pentenenitrile can be made more efficient. This is mainly because the treatment with the alkali source can form Si-OH structures on the surface of the molecular sieve particles, which is convenient for forming Si-O-Si structures with the Si-OH structures on other particles or after hydrolysis of the binder and thus connecting them. This structure has three functions. First, it is convenient to combine with the Si-OH structure formed after hydrolysis of, for example, the Si-OCH3 (methoxysilane) structure in the amino modifier to form an Si-O-Si structure, thereby introducing alkylamine modification. Second, it is convenient to form Si-O-Si structures with the Si-OH structures on other particles or after hydrolysis of the binder and thus connect them. Third, after amino modification and the spray granulation process, the remaining Si-OH can provide a certain acidity during the reaction to assist the organic amine in catalyzing the conversion of 2-pentenenitrile to 3-pentenenitrile and 4-pentenenitrile.

[0023] Further, in step (1), the alkali source includes one or more of an inorganic base aqueous solution, a quaternary ammonium base aqueous solution, and a quaternary ammonium salt aqueous solution.

[0024] Exemplarily, the alkali source is a sodium hydroxide solution, a potassium hydroxide solution, ammonia water, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, an aqueous solution of cetyltrimethylammonium bromide and sodium hydroxide, etc.

[0025] Further, in step (1), the pure silica mesoporous molecular sieve includes one or more of MCM molecular sieves or SBA molecular sieves.

[0026] Exemplarily, the pure silica mesoporous molecular sieve is MCM-41, MCM-48, SBA-15, SBA-16, etc.

[0027] Further, in step (1), the concentration of the alkali source is 0.01 - 8 mol / L, and the mass ratio of the pure silica mesoporous molecular sieve to the alkali source is 1:(0.01 - 5).

[0028] Further, in step (2), the binder includes one or more of silica sol, water glass, tetraethyl orthosilicate, and diatomaceous earth.

[0029] Further, in step (2), the amino modifier includes one or more of organosilane compounds.

[0030] Exemplarily, the amino modifier is diethylenetriaminepropyltrimethoxysilane, aminopropyltriethoxysilane, 2-aminoethyl-3-aminopropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, 3-(methylamino)propyltrimethoxysilane, 3-(phenylamino)propyltrimethoxysilane, 3-[2-2(2-aminoethylamino)ethylamino]propyltrimethoxysilane, tetraethylenepentamine, triethylenetetramine, diethylenetriamine, polyethyleneimine, etc. Preferably, it is one or more of 3-aminopropyltrimethoxysilane, 2-aminoethyl-3-aminopropyltrimethoxysilane, 3-(methylamino)propyltrimethoxysilane, 3-[2-2(2-aminoethylamino)ethylamino]propyltrimethoxysilane.

[0031] Furthermore, the mass ratio of the pure silica mesoporous molecular sieve to the binder is 1:(1 - 20), and more preferably 1:(1 - 5). Furthermore, the mass ratio of the pure silica mesoporous molecular sieve to the amino modifier is 1:(0.1 - 10), and more preferably 1:(0.1 - 2).

[0032] On the other hand, the present invention also provides an amino-modified supported catalyst, which includes: a pure silica mesoporous molecular sieve, an amino modifier, and a binder, wherein the pure silica mesoporous molecular sieve is pretreated with an alkali source after calcination.

[0033] On the other hand, the present invention also provides an application of a preparation method of an amino-modified supported catalyst in an isomerization reaction, and the isomerization reaction includes converting a 2-pentenenitrile-containing material into 3-pentenenitrile and 4-pentenenitrile.

[0034] In the process of producing adiponitrile by the butadiene method using the amino-modified supported catalyst, the by-product 2-pentenenitrile can be effectively utilized, making the raw material utilization rate higher, the by-products less, reducing "three wastes", and further improving the production efficiency of adiponitrile.

[0035] Exemplarily, the 2-pentenenitrile-containing material can be a mixed material of 80.40% cis-2-pentenenitrile, 13.60% cis-2-methyl-2-buteneitrile, 1.11% trans-2-methyl-2-buteneitrile, 3.58% 2-methyl-3-buteneitrile, and 1.31% trans-2-pentenenitrile.

[0036] Furthermore, the isomerization reaction is carried out by adding the amino-modified supported catalyst and the 2-pentenenitrile-containing material into the reaction device according to a mass ratio of 1:(1 - 400), purging and replacing with nitrogen, and under the conditions of a pressure of 0 - 10 bar, a reaction temperature of 20 - 300 °C, and reacting for 1 - 24 h, and then obtaining 3-pentenenitrile and 4-pentenenitrile through filtration and rectification.

[0037] The conventional experimental process of the prior art is generally reflux under atmospheric pressure or a fixed-bed reaction after being turned into vapor. The isomerization reaction of the present invention is a pressurized liquid-phase reaction with a pressure of 0-10 bar.

[0038] Optionally, the reaction device is a slurry bed or a batch reactor;

[0039] Optionally, in the isomerization reaction, the amino-modified supported catalyst and 2-pentenenitrile or a material containing 2-pentenenitrile are put into the reaction kettle at a mass ratio of 1:(1-400). After purging and replacing with nitrogen, the pressure is increased to 0-10 bar. At 20-300 °C, the mixture stays for 1-24 h. After filtering off the solid particles through a filter, it enters the distillation device to separate 3-pentenenitrile, 4-pentenenitrile and by-products, including trans-2-pentenenitrile, cis- and trans-2-methyl-2-butenenitrile and 2-methyl-3-butenenitrile, etc. 3-pentenenitrile and 4-pentenenitrile can be further subjected to a two-step hydrocyanation reaction to produce adiponitrile, and the remaining cis-2-pentenenitrile is recycled back to the slurry bed reactor or the batch reactor of the present invention for continuous reaction.

[0040] Exemplarily, 1 g of the prepared amino-supported catalyst and 176 g of the reaction material (containing 80.40% of cis-2-pentenenitrile, 13.60% of cis-2-methyl-2-butenenitrile, 1.11% of trans-2-methyl-2-butenenitrile, 4.69% of 2-methyl-3-butenenitrile, and 1.31% of trans-2-pentenenitrile) are put into the reaction kettle. After purging and replacing with nitrogen, the pressure is increased to 1.5 bar and the reaction is carried out at 207 °C for 2 hours.

[0041] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0042] (1) In the preparation method of the amino-modified supported catalyst of the present invention, after the pure silica mesoporous molecular sieve is calcined and treated with alkali, amino modification is added, and direct spray granulation is carried out under the action of a binder to obtain a catalyst with good particle size. The catalyst prepared by this method is a heterogeneous catalyst, which is easier to separate the catalyst from the reaction system and is more suitable for industrial production.

[0043] (2) The amino-modified supported catalyst of the present invention avoids the oligomerization reaction caused by acidic sites, reduces the occurrence of side reactions, and makes the isomerization reaction more efficient.

[0044] (3) The preparation method of the amino-modified supported catalyst of the present invention can be applied in the process of producing adiponitrile by the butadiene method, which makes the raw material utilization rate higher, reduces "three wastes", and further improves the production efficiency of the process of producing adiponitrile by the butadiene method. Specific Embodiments

[0045] To facilitate the understanding of the present invention, the present invention will be described more comprehensively below, and preferred embodiments of the present invention are given. However, it should be understood that these embodiments are only for more detailed illustration and should not be construed as limiting the present invention in any form, that is, it is not intended to limit the protection scope of the present invention.

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

[0047] Preparation of Amino-Modified Supported Catalyst

[0048] Catalyst Preparation Example 1

[0049] 5.6 g of commercially available pure silica SBA-15 molecular sieve was calcined at 650 °C. After the calcined SBA-15 was treated with 100 mL of 1.5% NaOH (w / w) solution at 143 °C for 4 h, 2.65 g of amino modifier 2-aminoethyl-3-aminopropyltrimethoxysilane and 5.75 g of binder tetraethyl orthosilicate were added dropwise to the pure silica mesoporous molecular sieve suspension. After aging at 100 °C for 8 h, the alcohol was removed at 100 °C, sheared evenly with a shear machine, and spray granulated at 155 °C to obtain amino-modified supported catalyst 1, denoted as NSBA-15-01.

[0050] Catalyst Preparation Example 2

[0051] 5.6 g of commercially available pure silica MCM-41 molecular sieve was calcined at 550 °C. After the calcined MCM-41 was treated with 100 mL of quaternary ammonium salt base solution (containing 5.2 g of cetyltrimethylammonium bromide and 2 g of NaOH) at 120 °C for 6 h, 4.8 g of 3-aminopropyltrimethoxysilane and 6.33 g of water glass were added dropwise to the pure silica mesoporous molecular sieve suspension. After aging at 140 °C for 3 h, the alcohol was removed at 88 °C, sheared evenly with a shear machine, and spray granulated at 175 °C. Then, 5 g of dry granular catalyst was taken and treated with 12 g of anhydrous methanol at 100 °C under reflux condensation for 2 h, filtered, and dried in a vacuum drying oven to obtain amino-modified supported catalyst 2, denoted as NMCM-41-01.

[0052] Catalyst Preparation Example 3

[0053] 5.6 g of commercially available pure silica MCM-48 molecular sieve was calcined at 700 °C. After the calcined MCM-48 was treated with 66 mL of 10% tetrabutylammonium hydroxide at 98 °C for 11 h, a mixture of 2.07 g of 2-aminoethyl-3-aminopropyltrimethoxysilane and 3.78 g of 3-(methylamino)propyltrimethoxysilane was added dropwise to the pure silica mesoporous molecular sieve suspension. Then, 4.97 g of silica sol was added. After aging at 150 °C for 3 h, the alcohol was removed at 70 °C, and it was sheared evenly using a shear machine. After spray granulation at 216 °C, 5 g of the dried catalyst particles were taken and treated with 17.5 g of absolute ethanol at 78 °C under condensing reflux for 2 h, then filtered and dried in a vacuum drying oven to obtain the amino-modified supported catalyst 3, denoted as NMCM-48-01.

[0054] Catalyst Preparation Example 4

[0055] 5.6 g of commercially available pure silica SBA-16 molecular sieve was calcined at 450 °C. After the calcined SBA-16 molecular sieve was treated with 100 mL of 20% ammonia water solution at 78 °C for 24 h, 8.88 g of an amino-modifying agent mixed solution was added dropwise to the pure silica mesoporous molecular sieve suspension. This solution was a mixed solution containing 60% 3-aminopropyltrimethoxysilane and 40% 3-[2-2(2-aminoethylamino)ethylamino]propyltrimethoxysilane. Subsequently, 15.78 g of diatomite was added. After aging at 92 °C for 12 h, the alcohol and free ammonia were removed at 78 °C, and it was sheared evenly using a shear machine. After spray granulation at 137 °C, the amino-modified supported catalyst 4 was obtained, denoted as NSBA-16-01.

[0056] Preparation of the comparative example of the amino-modified supported catalyst

[0057] Catalyst Comparative Example 1

[0058] Compared with Preparation Example 2 of the catalyst, in Comparative Example 1 of the catalyst, no alkali source was used for pretreatment, and the specific process is as follows:

[0059] 5.6 g of commercially available pure silica MCM-41 molecular sieve was calcined at a certain temperature of 550 °C. After the calcined MCM-41 was mixed with 100 mL of deionized water, 4.8 g of 3-aminopropyltrimethoxysilane and 6.33 g of water glass were added dropwise to the obtained suspension. After aging at 140 °C for 3 h, the alcohol was removed at 88 °C, and it was sheared evenly using a shear machine. After spray granulation at 175 °C, 5 g of the dried granular catalyst were taken and treated with 12 g of absolute methanol at 100 °C under condensing reflux for 2 h, then filtered and dried in a vacuum drying oven to obtain the comparative agent 1 of the amino-modified supported catalyst, denoted as MCM-41-DB-01.

[0060] Catalyst Comparative Example 2

[0061] Compared with Preparation Example 2 of the catalyst, in Comparative Example 2 of the catalyst, the amino modifier 3-aminopropyltrimethoxysilane is not added. The specific process is as follows:

[0062] 5.6 g of commercially available pure silica MCM-41 molecular sieve was calcined at 550 °C. After calcination, the MCM-41 was treated with 100 mL of quaternary ammonium salt base solution (containing 5.2 g of cetyltrimethylammonium bromide and 2 g of NaOH) at 120 °C for 6 h. Then, 6.33 g of water glass was added dropwise to the pure silica mesoporous molecular sieve suspension. After aging at 140 °C for 3 h, the alcohol was removed at 88 °C, and it was sheared evenly with a shear machine. After spray granulation at 175 °C, 5 g of dry granular catalyst was taken and treated with 12 g of anhydrous methanol at 100 °C under reflux condensation for 2 h, then filtered and dried in a vacuum drying oven to obtain the contrast agent 2 of the amino-modified supported catalyst, denoted as MCM-41-DB-02.

[0063] Catalyst Comparative Example 3

[0064] Compared with Preparation Example 2 of the catalyst, in Comparative Example 3 of the catalyst, the binder water glass is not added. The specific process is as follows:

[0065] 5.6 g of commercially available pure silica MCM-41 molecular sieve was calcined at 550 °C. After calcination, the MCM-41 was treated with 100 mL of quaternary ammonium salt base solution (containing 5.2 g of cetyltrimethylammonium bromide and 2 g of NaOH) at 120 °C for 6 h. Then, 4.8 g of 3-aminopropyltrimethoxysilane was added dropwise to the pure silica mesoporous molecular sieve suspension. After aging at 140 °C for 3 h, the alcohol was removed at 88 °C, and it was sheared evenly with a shear machine. After spray granulation at 175 °C, 5 g of dry granular catalyst was taken and treated with 12 g of anhydrous methanol at 100 °C under reflux condensation for 2 h, then filtered and dried in a vacuum drying oven to obtain the contrast agent 3 of the amino-modified supported catalyst, denoted as MCM-41-DB-03.

[0066] Catalyst Comparative Example 4

[0067] Compared with Preparation Example 2 of the catalyst, in Comparative Example 4 of the catalyst, the dosage of the base source is different. The specific process is as follows:

[0068] 5.6 g of commercially available pure silica MCM-41 molecular sieve was calcined at 550 °C. After calcination, the MCM-41 was treated with 100 mL of quaternary ammonium salt solution (containing 5.2 g of cetyltrimethylammonium bromide and 32 g of NaOH) at 120 °C for 6 h. Then, 4.8 g of 3-aminopropyltrimethoxysilane and 6.33 g of sodium silicate were added dropwise to the pure silica mesoporous molecular sieve suspension. After aging at 140 °C for 3 h, the alcohol was removed at 88 °C, and it was sheared evenly with a shear machine. After spray granulation at 175 °C, 5 g of dry granular catalyst was taken and treated with 12 g of anhydrous methanol at 100 °C under reflux condensation for 2 h, then filtered and dried in a vacuum drying oven to obtain the contrast agent 4 of the amino-modified supported catalyst, denoted as MCM-41-DB-04.

[0069] Catalyst Comparative Example 5

[0070] Compared with Preparation Example 2 of the catalyst, the amount of the amino modifier 3-aminopropyltrimethoxysilane in Comparative Example 5 of the catalyst was different. The specific process is as follows:

[0071] 5.6 g of commercially available pure silica MCM-41 molecular sieve was calcined at 550 °C. After calcination, the MCM-41 was treated with 100 mL of quaternary ammonium salt solution (containing 5.2 g of cetyltrimethylammonium bromide and 2 g of NaOH) at 120 °C for 6 h. Then, 60 g of 3-aminopropyltrimethoxysilane and 6.33 g of sodium silicate were added dropwise to the pure silica mesoporous molecular sieve suspension. After aging at 140 °C for 3 h, the alcohol was removed at 88 °C, and it was sheared evenly with a shear machine. After spray granulation at 175 °C, 5 g of dry granular catalyst was taken and treated with 12 g of anhydrous methanol at 100 °C under reflux condensation for 2 h, then filtered and dried in a vacuum drying oven to obtain the contrast agent 5 of the amino-modified supported catalyst, denoted as MCM-41-DB-05.

[0072] Catalyst Comparative Example 6

[0073] Compared with Preparation Example 2 of the catalyst, the amount of the binder sodium silicate in Comparative Example 6 of the catalyst was different. The specific process is as follows:

[0074] 5.6 g of commercially available pure silica MCM-41 molecular sieve was calcined at 550 °C. After calcination, the MCM-41 was treated with 100 mL of quaternary ammonium salt solution (containing 5.2 g of cetyltrimethylammonium bromide and 2 g of NaOH) at 120 °C for 6 h. Then, 4.8 g of 3-aminopropyltrimethoxysilane and 120 g of water glass were added dropwise to the pure silica mesoporous molecular sieve suspension. After aging at 140 °C for 3 h, the alcohol was removed at 88 °C, and the mixture was sheared evenly using a shear machine. After spray granulation at 175 °C, 5 g of dry granular catalyst was taken and treated with 12 g of anhydrous methanol at 100 °C under reflux condensation for 2 h. Then, it was filtered and dried in a vacuum drying oven to obtain the contrast agent 6 of the amino-modified supported catalyst, denoted as MCM-41-DB-06.

[0075] Application of Amino-Modified Supported Catalyst in Isomerization Reaction

[0076] Example 1

[0077] 1 g of NSBA-15-01 and 51.5 g of reaction materials (containing 80.40% of cis-2-pentenenitrile, 13.60% of cis-2-methyl-2-butenenitrile, 1.11% of trans-2-methyl-2-butenenitrile, 4.69% of 2-methyl-3-butenenitrile, and 1.31% of trans-2-pentenenitrile) were put into a reaction kettle. After purging with nitrogen, the pressure was increased to 6.0 bar, and the reaction was carried out at 149 °C for 4 h. After solid-liquid separation, the reaction solution was taken for gas chromatography analysis. The analysis results are listed in Table 1.

[0078] Example 2

[0079] 1 g of NMCM-41-01 and 19.5 g of reaction materials (containing 80.40% of cis-2-pentenenitrile, 13.60% of cis-2-methyl-2-butenenitrile, 1.11% of trans-2-methyl-2-butenenitrile, 4.69% of 2-methyl-3-butenenitrile, and 1.31% of trans-2-pentenenitrile) were put into a reaction kettle. After purging with nitrogen, the pressure was increased to 7.5 bar, and the reaction was carried out at 121 °C for 8 h. After solid-liquid separation, the reaction solution was taken for gas chromatography analysis. The analysis results are listed in Table 1.

[0080] Example 3

[0081] 1 g of NMCM-48-01 and 115 g of reaction materials (containing 80.40% of cis-2-pentenenitrile, 13.60% of cis-2-methyl-2-butenenitrile, 1.11% of trans-2-methyl-2-butenenitrile, 4.69% of 2-methyl-3-butenenitrile, and 1.31% of trans-2-pentenenitrile) were put into a reaction kettle. After purging with nitrogen, the pressure was increased to 4 bar, and the reaction was carried out at 178 °C for 3 h. After solid-liquid separation, the reaction solution was taken for gas chromatography analysis. The analysis results are listed in Table 1.

[0082] Example 4

[0083] Put 1 g of NSBA-16-01 and 176 g of the reaction material (containing 80.40% of cis-2-pentenenitrile, 13.60% of cis-2-methyl-2-butenenitrile, 1.11% of trans-2-methyl-2-butenenitrile, 4.69% of 2-methyl-3-butenenitrile, and 1.31% of trans-2-pentenenitrile) into the reaction kettle. After purging with nitrogen, pressurize to 1.5 bar and react at 207 °C for 2 hours. After solid-liquid separation, take the reaction solution and analyze it by gas chromatography. The analysis results are listed in Table 1.

[0084] Comparative Example 1

[0085] Put 1 g of commercially available pure silica SBA-15 molecular sieve after calcination and 19.5 g of the reaction material (containing 80.40% of cis-2-pentenenitrile, 13.60% of cis-2-methyl-2-butenenitrile, 1.11% of trans-2-methyl-2-butenenitrile, 4.69% of 2-methyl-3-butenenitrile, and 1.31% of trans-2-pentenenitrile) into the reaction kettle. After purging with nitrogen, pressurize to 7.5 bar and react at 121 °C for 8 hours. After solid-liquid separation, take the reaction solution and analyze it by gas chromatography. The analysis results are listed in Table 1.

[0086] Comparative Example 2

[0087] Put 1 g of commercially available pure silica MCM-41 molecular sieve after calcination and 19.5 g of the reaction material (containing 80.40% of cis-2-pentenenitrile, 13.60% of cis-2-methyl-2-butenenitrile, 1.11% of trans-2-methyl-2-butenenitrile, 4.69% of 2-methyl-3-butenenitrile, and 1.31% of trans-2-pentenenitrile) into the reaction kettle. After purging with nitrogen, pressurize to 7.5 bar and react at 121 °C for 8 hours. After solid-liquid separation, take the reaction solution and analyze it by gas chromatography. The analysis results are listed in Table 1.

[0088] Comparative Example 3

[0089] Put 1 g of commercially available pure silica MCM-48 molecular sieve after calcination and 115 g of the reaction material (containing 80.40% of cis-2-pentenenitrile, 13.60% of cis-2-methyl-2-butenenitrile, 1.11% of trans-2-methyl-2-butenenitrile, 4.69% of 2-methyl-3-butenenitrile, and 1.31% of trans-2-pentenenitrile) into the reaction kettle. After purging with nitrogen, pressurize to 4 bar and react at 178 °C for 3 hours. After solid-liquid separation, take the reaction solution and analyze it by gas chromatography. The analysis results are listed in Table 1.

[0090] Comparative Example 4

[0091] Put 1 g of commercially available pure silica SBA-16 molecular sieve after calcination and 115 g of reaction material (containing 80.40% of cis-2-pentenenitrile, 13.60% of cis-2-methyl-2-butenenitrile, 1.11% of trans-2-methyl-2-butenenitrile, 4.69% of 2-methyl-3-butenenitrile, and 1.31% of trans-2-pentenenitrile) into a reaction kettle. After purging with nitrogen, pressurize to 4 bar and react at 178 °C for 3 hours. After solid-liquid separation, take the reaction solution for gas chromatography analysis. The analysis results are listed in Table 1.

[0092] Comparative Example 5

[0093] Put 1 g of MCM-41-DB-01 and 19.5 g of reaction material (containing 80.40% of cis-2-pentenenitrile, 13.60% of cis-2-methyl-2-butenenitrile, 1.11% of trans-2-methyl-2-butenenitrile, 3.58% of 2-methyl-3-butenenitrile, and 1.31% of trans-2-pentenenitrile) into a reaction kettle. After purging with nitrogen, pressurize to 7.5 bar and react at 121 °C for 8 hours. After solid-liquid separation, take the reaction solution for gas chromatography analysis. The analysis results are listed in Table 1.

[0094] Comparative Example 6

[0095] Put 1 g of MCM-41-DB-02 and 19.5 g of reaction material (containing 80.40% of cis-2-pentenenitrile, 13.60% of cis-2-methyl-2-butenenitrile, 1.11% of trans-2-methyl-2-butenenitrile, 3.58% of 2-methyl-3-butenenitrile, and 1.31% of trans-2-pentenenitrile) into a reaction kettle. After purging with nitrogen, pressurize to 7.5 bar and react at 121 °C for 8 hours. After solid-liquid separation, take the reaction solution for gas chromatography analysis. The analysis results are listed in Table 1.

[0096] Comparative Example 7

[0097] Put 1 g of MCM-41-DB-03 and 19.5 g of reaction material (containing 80.40% of cis-2-pentenenitrile, 13.60% of cis-2-methyl-2-butenenitrile, 1.11% of trans-2-methyl-2-butenenitrile, 3.58% of 2-methyl-3-butenenitrile, and 1.31% of trans-2-pentenenitrile) into a reaction kettle. After purging with nitrogen, pressurize to 7.5 bar and react at 121 °C for 8 hours. After solid-liquid separation, take the reaction solution for gas chromatography analysis. The analysis results are listed in Table 1.

[0098] Comparative Example 8

[0099] 1 g of MCM-41-DB-04 and 19.5 g of the reaction material (containing 80.40% of cis-2-pentenenitrile, 13.60% of cis-2-methyl-2-butenenitrile, 1.11% of trans-2-methyl-2-butenenitrile, 3.58% of 2-methyl-3-butenenitrile, and 1.31% of trans-2-pentenenitrile) were charged into a reaction kettle. After purging with nitrogen, the pressure was increased to 7.5 bar, and the reaction was carried out at 121 °C for 8 hours. After solid-liquid separation, the reaction solution was taken for gas chromatography analysis. The analysis results are listed in Table 1.

[0100] Comparative Example 9

[0101] 1 g of MCM-41-DB-05 and 19.5 g of the reaction material (containing 80.40% of cis-2-pentenenitrile, 13.60% of cis-2-methyl-2-butenenitrile, 1.11% of trans-2-methyl-2-butenenitrile, 3.58% of 2-methyl-3-butenenitrile, and 1.31% of trans-2-pentenenitrile) were charged into a reaction kettle. After purging with nitrogen, the pressure was increased to 7.5 bar, and the reaction was carried out at 121 °C for 8 hours. After solid-liquid separation, the reaction solution was taken for gas chromatography analysis. The analysis results are listed in Table 1.

[0102] Comparative Example 10

[0103] 1 g of MCM-41-DB-06 and 19.5 g of the reaction material (containing 80.40% of cis-2-pentenenitrile, 13.60% of cis-2-methyl-2-butenenitrile, 1.11% of trans-2-methyl-2-butenenitrile, 3.58% of 2-methyl-3-butenenitrile, and 1.31% of trans-2-pentenenitrile) were charged into a reaction kettle. After purging with nitrogen, the pressure was increased to 7.5 bar, and the reaction was carried out at 121 °C for 8 hours. After solid-liquid separation, the reaction solution was taken for gas chromatography analysis. The analysis results are listed in Table 1.

[0104] Table 1 Gas Chromatography Analysis Results

[0105]

[0106] Among them, C2PN: cis-2-pentenenitrile; T2PN: trans-2-pentenenitrile; C2M2BN: cis-2-methyl-2-butenenitrile; T2M2BN: trans-2-methyl-2-butenenitrile; 2M3BN: 2-methyl-3-butenenitrile; C3PN: cis-3-pentenenitrile; 4PN: 4-pentenenitrile; High Boiling: High boiling point components (including trans-3-pentenenitrile)

[0107] As can be seen from the gas chromatograph analysis results in Table 1, the amino-supported catalyst prepared by the present invention can catalyze the conversion of the material containing 2-pentenenitrile into cis-3-pentenenitrile and 4-pentenenitrile, and has a higher conversion rate compared with the commercially available catalysts (Comparative Examples 1-4) only calcined; compared with Comparative Example 5 (using the catalyst MCM-41-DB-01 pretreated with a different base source), the yield of cis-3-pentenenitrile in Example 2 is 6.41%, while the yield of cis-3-pentenenitrile in Comparative Example 5 is only 0.35%. Therefore, the pretreatment of the amino-modified supported catalyst with a base source has a better effect; compared with Comparative Example 6 (using the catalyst MCM-41-DB-02 without adding an amino modifier), Comparative Example 6 cannot achieve the conversion of the material containing 2-pentenenitrile into cis-3-pentenenitrile and 4-pentenenitrile; compared with Comparative Example 7 (using the catalyst MCM-41-DB-03 without adding a binder), the yields of cis-3-pentenenitrile and 4-pentenenitrile in Example 2 are both higher than those in Comparative Example 7. Therefore, adding a binder to the amino-modified supported catalyst has a better effect than not adding a binder; at the same time, compared with Comparative Example 8 (using the catalyst MCM-41-DB-04 with a base source content outside the scope of the present invention), Comparative Example 9 (using the catalyst MCM-41-DB-05 with an amino modifier content outside the scope of the present invention), and Comparative Example 10 (using the catalyst MCM-41-DB-06 with a binder content outside the scope of the present invention), the conversion rates of the 2-pentenenitrile material into cis-3-pentenenitrile and 4-pentenenitrile are all lower than those in Example 2 of the present invention.

[0108] When the product of Example 2 containing 71.54% of cis-2-pentenenitrile, 12.76% of cis-2-methyl-2-buteneitrile, 1.71% of trans-2-methyl-2-buteneitrile, 4.34% of 2-methyl-3-buteneitrile, and 1.56% of trans-2-pentenenitrile was separated, the fraction with a boiling point less than 142 °C was distilled off, and the evaluation was continued according to the evaluation process of Example 2. After repeating 10 times, the materials were mixed. The reacted material contained 26.57% of cis-2-pentenenitrile, 7.63% of cis-2-methyl-2-buteneitrile, 2.53% of trans-2-methyl-2-buteneitrile, 3.22% of 2-methyl-3-buteneitrile, and 2.21% of trans-2-pentenenitrile. Therefore, by distilling off the light components after the reaction and reacting the light components again, a high conversion rate of cis-2-pentenenitrile and high yields of cis-3-pentenenitrile and 4-pentenenitrile can be obtained.

[0109] It should be noted that side reactions exist in the actual reaction process. While the main reaction is the conversion to cis-3-pentenenitrile, side reactions also occur, with the conversion from cis-2-pentenenitrile to trans-2-pentenenitrile, resulting in an increase in the content of trans-2-pentenenitrile. For reference, in the method of CN1777578B for isomerizing cis-2-pentenenitrile to form trans-3-pentenenitrile, in Examples 1-5, using 98% of 2-pentenenitrile raw material, a relatively large amount of trans-2-pentenenitrile will be obtained, and the yield is about 15%-34%. Similarly, in the comparative literature CN100567258C for the homogeneous isomerization of cis-2-pentenenitrile to 3-pentenenitrile, the content of trans-2-pentenenitrile also gradually increases with the prolongation of the reaction time. For example, in Example 1, the content of trans-2-pentenenitrile increases from 1% (reaction for 2 hours) to 3% (6 hours). Therefore, the increase in the content of trans-2-pentenenitrile is a normal process of this reaction.

[0110] In summary, after the pure silica mesoporous molecular sieve is calcined and treated with alkali, amino modification is added, and it is directly spray granulated under the action of a binder to obtain an amino-loaded catalyst with good particle size. This avoids the oligomerization reaction caused by acidic sites, reduces the occurrence of side reactions, makes the isomerization reaction more efficient. At the same time, the catalyst is a heterogeneous catalyst, which is easier to separate the catalyst from the reaction system and is more suitable for industrial production. The preparation method of the amino-modified supported catalyst is applied in the process of producing adiponitrile by the butadiene method to realize the heterogeneous catalytic conversion process of 2-pentenenitrile to 3-pentenenitrile and even 4-pentenenitrile, making the raw material utilization rate higher, reducing "three wastes", and further improving the production efficiency of the process of producing adiponitrile by the butadiene method.

[0111] It should be noted that the above content is a further detailed description of the present invention in combination with specific embodiments, and it cannot be determined that the specific implementation of the present invention is only limited to these descriptions. For those of ordinary skill in the technical field to which the present invention belongs, without departing from the concept of the present invention, several simple improvements and refinements can be made, which should all be regarded as belonging to the protection scope of the present invention.

Claims

1. A preparation method of an amino-modified supported catalyst, characterized in that, It includes the following steps: Step (1): Calcinate the pure silica mesoporous molecular sieve and then pretreat it with an alkali source to obtain a pure silica mesoporous molecular sieve suspension; Step (2): Add an amino modifier and a binder to the pure silica mesoporous molecular sieve suspension, and obtain a granular catalyst after aging, alcohol removal, shearing and spray granulation; Step (3): Subject the granular catalyst to solvothermal treatment and vacuum drying to obtain an amino-modified supported catalyst.

2. The preparation method of an amino-modified supported catalyst according to claim 1, characterized in that, In the step (1), the alkali source includes one or more of an inorganic base aqueous solution, a quaternary ammonium base aqueous solution, and a quaternary ammonium salt aqueous solution.

3. The preparation method of an amino-modified supported catalyst according to claim 1, characterized in that, In the step (1), the pure silica mesoporous molecular sieve includes one or more of a pure silica MCM molecular sieve or a pure silica SBA molecular sieve.

4. The preparation method of an amino-modified supported catalyst according to claim 1, characterized in that, In the step (1), the concentration of the alkali source is 0.01 - 8 mol / L, and the mass ratio of the pure silica mesoporous molecular sieve to the alkali source is 1:(0.01 - 5).

5. The preparation method of an amino-modified supported catalyst according to claim 1, characterized in that, In the step (2), the binder includes one or more of silica sol, water glass, tetraethyl orthosilicate, and diatomite.

6. The preparation method of an amino-modified supported catalyst according to claim 1, characterized in that, The amino modifier includes one or more of organosilane compounds, preferably one or more of 3-aminopropyltrimethoxysilane, 2-aminoethyl-3-aminopropyltrimethoxysilane, 3-(methylamino)propyltrimethoxysilane, and 3-[2-2(2-aminoethylamino)ethylamino]propyltrimethoxysilane.

7. The preparation method of an amino-modified supported catalyst according to claim 1, characterized in that, The mass ratio of the pure silica mesoporous molecular sieve to the binder is 1:(1 - 20), preferably 1:(1 - 5). And / or, the mass ratio of the pure silica mesoporous molecular sieve to the amino modifier is: 1:(0.1 - 10), preferably 1:(0.1 - 2).

8. An amino-modified supported catalyst, characterized in that, The amino-modified supported catalyst includes: a pure silica mesoporous molecular sieve, an amino modifier, and a binder, wherein the pure silica mesoporous molecular sieve is calcined and then pretreated with an alkali source.

9. Use of the preparation method according to any one of claims 1 to 7 in an isomerization reaction, characterized in that, The isomerization reaction includes converting a 2-pentenenitrile-containing material into 3-pentenenitrile and 4-pentenenitrile.

10. The application according to claim 9, characterized in that, In the isomerization reaction, the amino-modified supported catalyst and the 2-pentenenitrile-containing material are added to the reaction device according to a mass ratio of 1:(1 - 400), and after purging and displacing with nitrogen, at a pressure of 0 - 10 bar and a reaction temperature of 20 - 300 °C, after reacting for 1 - 24 h, 3-pentenenitrile and 4-pentenenitrile are obtained.

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