Preparation method and application of styryl amino caprolactam and functional nylon-6

Abstract

The invention relates to the technical field of organic synthesis, in particular to a preparation method and application of styryl amino caprolactam and functional nylon-6. The preparation method comprises the following steps: in an inert atmosphere, amino caprolactam and / or a derivative thereof, benzaldehyde and a catalyst are contacted and react in a solvent to obtain styryl amino caprolactam; wherein the reaction temperature ranges from 30 DEG C to 120 DEG C. According to the preparation method, high raw material conversion rate and high target product selectivity are obtained under mild reaction conditions; meanwhile, the preparation method also has the advantages of simple process, greenness, environmental protection and the like, and is convenient for industrial production.

Description

Technical Field

[0001] The present invention relates to the technical field of organic synthesis, and particularly relates to a preparation method and application of styryl amino caprolactam, and a functional nylon-6. Background Art

[0002] At present, the over-rapid growth of caprolactam production capacity has brought problems such as oversupply and fierce market competition, and it is necessary to actively expand and develop new application fields of caprolactam. Among them, functional nylon materials with antibacterial, fluorescent, elastic, flame-retardant, wear-resistant and other properties have a large market demand, but due to problems in material properties, manufacturing costs and other aspects, most of these functional materials are in the laboratory research and development stage. Starting from caprolactam or its derivatives and performing functional modification on them to obtain functional caprolactam monomers with special structures and properties can realize the preparation of functional nylon materials at the polymerization monomer level.

[0003] CN103694174A discloses a preparation method of an amino caprolactam derivative with a benzaldehyde derivative as an α-amino substituent, using NaBH4 or NaBH3CN as a hydrogenation reagent in the system. CN102093292A discloses a preparation method of DL-α-amino caprolactam. US5703208A discloses a synthesis method of an aromatic functional caprolactam. The reaction conditions used are toluene reflux for 4 h, and α-halogenated caprolactam reacts with benzylamine under alkaline conditions to generate a monobenzyl-derived functional caprolactam; the monobenzyl-derived functional caprolactam can be converted into DL-α-amino caprolactam by reflux hydrogenation catalysis. CN109320455A discloses a purification method of DL-α-amino caprolactam, and this method also uses α-halogenated caprolactam to react with benzylamine under alkaline conditions to generate a monobenzyl-derived functional caprolactam.

[0004] The above-mentioned prior arts have promoted the development of the synthesis route of aromatic functional caprolactam to a certain extent, but there are the following problems: (1) Halides and borohydrides are highly toxic and have poor chemical stability, which will cause serious pollution to the environment; (2) The reaction efficiency is low, and the reaction system is not green, with great environmental protection pressure, which is not conducive to the scale production of target products.

[0005] Therefore, developing efficient and low-cost catalysts and supporting catalytic reaction systems is of great significance for promoting the development of the catalytic synthesis system of functional caprolactam monomers and the production, application and popularization of monomers. Summary of the Invention

[0006] The object of the present invention is to overcome the above technical problems, and to provide a preparation method of styryl aminocaprolactam and its application, and a functional nylon-6. The preparation method can obtain high raw material conversion rate and high target product selectivity under mild reaction conditions. At the same time, the preparation method also has the advantages of simple process, environmental friendliness, etc., which is convenient for industrial production.

[0007] To achieve the above object, in the first aspect, the present invention provides a preparation method of styryl aminocaprolactam, the preparation method comprising: in an inert atmosphere, contacting and reacting aminocaprolactam and / or its derivatives, benzaldehyde and a catalyst in a solvent to obtain styryl aminocaprolactam; wherein, the reaction temperature is 30-120°C.

[0008] In the second aspect, the present invention provides an application of styryl aminocaprolactam prepared by the preparation method provided in the first aspect as a polymerization monomer in the preparation of functional nylon-6.

[0009] In the third aspect, the present invention provides a functional nylon-6, which contains styryl aminocaprolactam prepared by the preparation method provided in the first aspect.

[0010] Compared with the prior art, the present invention has the following advantages:

[0011] (1) The preparation method provided by the present invention uses aminocaprolactam and / or its derivatives and benzaldehyde as raw materials, combined with a catalyst and a solvent, and can efficiently obtain high raw material conversion rate and high target product selectivity under mild reaction conditions; in particular, by adjusting the type of catalyst and limiting the B acid density and L acid density of a specific catalyst, the catalytic efficiency is further improved; at the same time, the process flow is simplified, the operation is simple, the environment is friendly, and it is convenient for industrial production;

[0012] (2) Styryl aminocaprolactam prepared by the preparation method provided by the present invention is used as a polymerization monomer in the preparation of functional nylon-6 materials such as antibacterial, luminescent, and elastomer materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 is the synthesis route of styryl aminocaprolactam provided by the present invention;

[0014] Figure 2(a) is the transmission infrared spectrum of catalyst S1 prepared in Preparation Example 1, and Figure 2(b) is the transmission infrared spectrum of catalyst S8 prepared in Preparation Example 8. Among them, the signal peaks at wavenumbers of 1066 cm -1 and 1160 cm -1 are the vibration absorption peaks of Si-O-Si and Si-O-Al bonds respectively;

[0015] Figure 3are the pyridine infrared characterization spectra of the catalyst S1 prepared in Preparation Example 1 and the catalysts S8 - S9 prepared in Preparation Examples 8 - 9. Among them, the absorption peak at a wave number of 1540 cm -1 indicates the B acid sites on the catalyst surface, and the absorption peak at a wave number of 1450 cm -1 indicates the L acid sites on the catalyst surface;

[0016] Figure 4 is the SEM image of the catalyst S1 prepared in Preparation Example 1. Detailed implementation manners

[0017] In the ranges disclosed herein, the endpoints and any values are not limited to the exact ranges or values. These ranges or values should be understood to include values close to these ranges or values. For numerical ranges, between the endpoint values of each range, between the endpoint values of each range and individual point values, and between individual point values, they can be combined with each other to obtain one or more new numerical ranges, and these numerical ranges should be regarded as specifically disclosed herein.

[0018] In the present invention, without special circumstances, "first", "second", and "third" neither represent the order nor limit each material or step, but are only used to distinguish that these are not the same material or step. For example, in "first mixing", "second mixing", and "third mixing", "first", "second", and "third" are only used to indicate that these are not the same mixing.

[0019] The first aspect of the present invention provides a method for preparing styryl aminocaprolactam. The preparation method includes: in an inert atmosphere, contacting and reacting aminocaprolactam and / or its derivatives, benzaldehyde, and a catalyst in a solvent to obtain styryl aminocaprolactam; wherein, the temperature of the reaction is 30 - 120 °C.

[0020] In some embodiments of the present invention, as Figure 1 shown, in an inert atmosphere, α - amino - ε - caprolactam and benzaldehyde are contacted and reacted in the presence of a catalyst and a solvent, and the molecular structure of the aromatic group - functionalized caprolactam obtained includes: the lactam ring of caprolactam, α - amino, and a carbon - nitrogen unsaturated double bond and a benzyl group derived from α - amino. In the present invention, the aromatic group - functionalized caprolactam is selected from styryl aminocaprolactam.

[0021] In some embodiments of the present invention, the temperature of the reaction is 30 - 120 °C, for example, 30 °C, 50 °C, 60 °C, 70 °C, 80 °C, 90 °C, 100 °C, 120 °C, and any value within the range composed of any two of these values. Preferably, it is 50 - 100 °C, and more preferably 50 - 70 °C. In the present invention, adopting the reaction temperature within the above range is more conducive to improving the raw material conversion rate and the selectivity of the target product, and thus improving the yield of the target product.

[0022] In some embodiments of the present invention, preferably, the reaction conditions further include: the pressure is 0.1 - 10 MPa, preferably 0.5 - 3 MPa; the time is 0.5 - 5 h, preferably 1 - 3 h. In the present invention, unless otherwise specified, the pressure refers to the gauge pressure.

[0023] In the present invention, the inert atmosphere includes, but is not limited to, nitrogen atmosphere, helium atmosphere, and argon atmosphere.

[0024] In some embodiments of the present invention, preferably, the mass ratio of the aminocaprolactam and / or its derivative to benzaldehyde is 1:0.2 - 4, for example, 1:0.2, 1:0.4, 1:0.5, 1:0.6, 1:0.7, 1:0.8, 1:0.9, 1:1, 1:1.1, 1:1.2, 1:1.5, 1:2, 1:3, 1:4, and any value within the range composed of any two of these values. Preferably, it is 1:0.5 - 1.2. Adopting the preferred mass ratio range is more conducive to improving the selectivity of the target product, and thus improving the yield of the target product.

[0025] In the present invention, unless otherwise specified, the aminocaprolactam and / or its derivative is selected from aminocaprolactam and / or aminocaprolactam derivatives.

[0026] In some embodiments of the present invention, preferably, the aminocaprolactam and / or its derivative is selected from aminocaprolactam and / or aminocaprolactam salts. In the present invention, the aminocaprolactam salts include, but are not limited to, at least one of hydrochloride, sulfate, and nitrate.

[0027] In some embodiments of the present invention, more preferably, the aminocaprolactam and / or its derivative is selected from at least one of DL-α-amino-ε-caprolactam, DL-α-amino-ε-caprolactam hydrochloride, DL-α-amino-ε-caprolactam sulfate, and DL-α-amino-ε-caprolactam nitrate.

[0028] In some embodiments of the present invention, preferably, the mass ratio of the amino caprolactam and / or its derivative to the catalyst is 1:0.1 - 10. For example, 1:0.1, 1:0.5, 1:1, 1:1.5, 1:2, 1:3, 1:4, 1:5, 1:8, 1:10, and any value within the range composed of any two numerical values. Preferably, it is 1:0.1 - 5, and more preferably 1:0.5 - 2. A mass ratio within the above range is more conducive to improving the conversion rate of the raw materials, and thus improving the yield of the target product.

[0029] In the present invention, the type of the catalyst is a conventional catalyst in the art, that is, a shaped catalyst. Preferably, the catalyst is selected from modified oxides; further preferably, the B acid density of the modified oxide is ≤2 μmol / g, preferably 0 - 2 μmol / g, further preferably 0 - 1.4 μmol / g, and more preferably 0 - 0.5 μmol / g; the L acid density is 50 - 300 μmol / g, preferably 90 - 200 μmol / g, and more preferably 100 - 150 μmol / g.

[0030] In some embodiments of the present invention, preferably, the catalyst is selected from silicon-modified alumina with a B acid density ≤2 μmol / g and an L acid density of 50 - 300 μmol / g. The silicon-modified alumina includes silicon and alumina; wherein, the silicon-aluminum ratio of the silicon-modified alumina is <1, and silicon is connected to the surface of alumina through Si-O-Al chemical bonds, and adjacent silicons on the surface of the alumina are connected through Si-O-Si chemical bonds.

[0031] The inventors of the present invention have found through research that: the surface of alumina has complex acidic sites, and different types and intensities of acidic sites greatly limit the application of alumina in the fine chemical industry. Therefore, silicon is loaded on the surface of alumina, and it is defined that silicon is connected to the surface of alumina through Si-O-Al chemical bonds, and it is defined that adjacent silicons on the surface of alumina are connected through Si-O-Si chemical bonds. On the premise of ensuring that the silicon-modified alumina has both a low attrition index, high crushing strength, high specific surface area and low average pore diameter, it can effectively mask the acidic sites on the surface of alumina, and then regulate the B acid density on the surface of the silicon-modified alumina, so that the B acid density of the silicon-modified alumina is ≤2 μmol / g; at the same time, the L acid density on the surface of alumina is also affected to a certain extent during the silicon modification process, so that the L acid density of the silicon-modified alumina is 50 - 300 μmol / g.

[0032] In the present invention, unless otherwise specified, the fact that silicon in the silicon-modified alumina is connected to the surface of alumina through Si-O-Al chemical bonds means that Si and Al in alumina share part of O, so that silicon existing in the form of SiOx is anchored on the surface of the alumina.

[0033] In the present invention, unless otherwise specified, the B acid density refers to the acid density; the L acid density refers to the Lewis acid density.

[0034] In the present invention, as Figure 3 shown, the B acid density parameter is calculated based on the amount of pyridine desorbed upon heating; B acid density = the amount of acid of the silicon-modified alumina indicated at the wavenumber of 1540 cm -1 in the pyridine infrared spectrum (in μmol) / the mass of the silicon-modified alumina (in g); the L acid density parameter is calculated based on the amount of pyridine desorbed upon heating; L acid density = the amount of acid of the silicon-modified alumina indicated at the wavenumber of 1450 cm -1 in the pyridine infrared spectrum (in μmol) / the mass of the silicon-modified alumina (in g).

[0035] In some embodiments of the present invention, preferably, the B acid density of the silicon-modified alumina is 0 - 2 μmol / g, for example, 0 μmol / g, 0.1 μmol / g, 0.2 μmol / g, 0.3 μmol / g, 0.5 μmol / g, 0.8 μmol / g, 1 μmol / g, 1.4 μmol / g, 1.5 μmol / g, 2 μmol / g, and any value within the range composed of any two numerical values, preferably 0 - 1.4 μmol / g, more preferably 0 - 0.5 μmol / g.

[0036] In some embodiments of the present invention, preferably, the L acid density of the silicon-modified alumina is 50 - 300 μmol / g, for example, 50 μmol / g, 50.1 μmol / g, 51 μmol / g, 60 μmol / g, 100 μmol / g, 151 μmol / g, 200 μmol / g, 300 μmol / g, and any value within the range composed of any two numerical values, preferably 90 - 200 μmol / g, more preferably 100 - 150 μmol / g.

[0037] In the present invention, the L acid can promote the reaction of the aldehyde group of benzaldehyde with the α-amino group of aminocaprolactam to obtain the target product; the reduction or elimination of the B acid can inhibit side reactions such as the alcoholysis ring-opening of aminocaprolactam, that is, the reduction of the B acid can indirectly increase the yield of the target product. Therefore, using silicon-modified alumina with a specific B acid density and a specific L acid density as the catalyst can effectively improve the selectivity of the target product.

[0038] In some embodiments of the present invention, preferably, the specific surface area of the silicon-modified alumina is 100 - 220 m 2 / g, for example, 100 m 2 / g, 120 m 2 / g, 150 m 2 / g, 180 m 2 / g, 200 m 2 / g, 220 m 2 / g, and any value within the range formed by any two of these numerical values, preferably 120 - 200 m 2 / g.

[0039] In some embodiments of the present invention, preferably, the average pore diameter of the silicon-modified alumina is 10 - 30 nm, for example, 10 nm, 15 nm, 20 nm, 25 nm, 30 nm, and any value within the range formed by any two of these numerical values, preferably 15 - 25 nm.

[0040] In some embodiments of the present invention, preferably, the attrition index of the silicon-modified alumina is 1 - 20%, for example, 1%, 2%, 5%, 8%, 10%, 12%, 15%, 20%, and any value within the range formed by any two of these numerical values, preferably 1 - 15%.

[0041] In some embodiments of the present invention, preferably, the crush strength of the silicon-modified alumina is 50 - 150 N / cm, for example, 50 N / cm, 70 N / cm, 80 N / cm, 100 N / cm, 110 N / cm, 130 N / cm, 150 N / cm, and any value within the range formed by any two of these numerical values, preferably 70 - 130 N / cm.

[0042] In the present invention, unless otherwise specified, the specific surface area parameter is measured using a fully automatic isothermal adsorption instrument; the average pore diameter parameter is obtained by using a fully automatic isothermal adsorption instrument in combination with the BJH model; the attrition index parameter is measured using an attrition index analyzer; the crush strength parameter is measured using a particle strength tester.

[0043] In the present invention, unless otherwise specified, except for silicon and alumina, there are no other impurities in the silicon-modified alumina, that is, the sum of the contents of silicon and alumina in the silicon-modified alumina is 100 wt%. Preferably, based on the total weight of the silicon-modified alumina, the content of alumina is 50 - 90 wt%, preferably 60 - 90 wt%; the content of silicon in terms of SiO x is 10 - 50 wt%, preferably 10 - 40 wt%; where 1 ≤ x ≤ 2.

[0044] In some embodiments of the present invention, preferably, the shape of the silicon-modified alumina is selected from spherical and strip-shaped, where the spherical shape includes but is not limited to microspherical and small spherical.

[0045] In some embodiments of the present invention, preferably, the alumina is selected from γ-alumina. Adopting the preferred conditions is more conducive to improving the activity of the silicon-modified alumina.

[0046] In the present invention, there is a wide range of choices for the preparation method of the silicon-modified alumina, as long as the silicon-modified alumina meets the above parameter limitations. Preferably, the silicon-modified alumina is prepared by the following method:

[0047] (1) Perform a first mixing of an aluminum source, an acidic compound, and water to obtain a first mixture;

[0048] (2) Successively perform shaping, first drying, and first calcination on the first mixture to obtain shaped alumina;

[0049] (3) Dissolve the shaped alumina in water, first add a basic compound to adjust the pH to 7-12, and then add a silicon source for a second mixing to obtain a second mixture;

[0050] (4) Perform solid-liquid separation on the second mixture, and the obtained silicon-modified alumina precursor is successively subjected to second drying and second calcination to obtain the silicon-modified alumina.

[0051] In some embodiments of the present invention, preferably, in step (1), in the first mixture, the content of the aluminum source is 0.01-10 wt%, preferably 0.05-5 wt%; the content of the acidic compound is 0.01-3 wt%, preferably 0.05-1 wt%. In the present invention, the feeding amount / usage ratio of the aluminum source, acidic compound, and water only needs to meet the above limitations.

[0052] In the present invention, there is a wide range of choices for the type of the aluminum source. Preferably, the aluminum source is a soluble aluminum salt, including but not limited to γ-alumina, hydroxyaluminum oxide, pseudoboehmite, aluminum chloride, aluminum nitrate, etc. When the aluminum source is selected from γ-alumina, steps (1)-(2) acidify the surface of the powdered alumina to form a hydrated hydroxyl state, facilitating subsequent addition of a basic compound and a silicon source for silicon modification.

[0053] In the present invention, there is a wide range of choices for the type of the acidic compound. Preferably, the acidic compound is selected from at least one of hydrochloric acid, nitric acid, sulfuric acid, and phosphoric acid. In the present invention, the acidic compound exists in the form of an aqueous solution, and preferably the concentration of the acidic compound in the acidic compound solution is 1-50 wt%.

[0054] In the present invention, there is a wide range of choices for the manner of the first mixing, and it is only necessary to mix the aluminum source, the acidic compound and water. Preferably, the conditions for the first mixing include: the temperature is 15 - 40°C, preferably 20 - 30°C; the rotation speed is 100 - 1000 rpm, preferably 300 - 1000 rpm; the time is 0.1 - 5 h, preferably 0.1 - 2 h.

[0055] In the present invention, there is a wide range of choices for the manner of the shaping. Preferably, in step (2), the manner of the shaping includes, but is not limited to, oil ammonia dropping ball shaping, spray drying shaping, and extrusion shaping.

[0056] In the present invention, the first drying aims to remove the water in the first mixture. Preferably, in step (2), the conditions for the first drying include: the temperature is 80 - 120°C, the time is 90 - 110°C; the time is 1 - 20 h, preferably 1 - 12 h.

[0057] In the present invention, there is a wide range of choices for the manner of the first drying, as long as the conditions for the first drying meet the above limitations. Preferably, the manner of the first drying includes, but is not limited to, spray drying, blast drying, vacuum drying, etc.

[0058] In some embodiments of the present invention, preferably, in step (2), the conditions for the first calcination include: the temperature is 700 - 1200°C, preferably 800 - 1000°C; the time is 1 - 10 h, preferably 1 - 5 h. In the present invention, the first calcination is carried out in a muffle furnace or a tube furnace, and the calcination atmosphere is a non - reducing gas, preferably at least one of air, nitrogen, and argon.

[0059] In the present invention, in step (3), first dissolve the shaped alumina in water, add an alkaline compound to adjust the pH, and then add a silicon source for the second mixing, aiming to obtain polyhydroxy silicic acid and / or hydroxy - hydrated silicon.

[0060] In some embodiments of the present invention, preferably, the pH is adjusted to 8 - 12, for example, 8, 9, 10, 10.5, 11, 11.5, 12, and any value within the range composed of any two of these values, preferably 10.5 - 11.5.

[0061] In some embodiments of the present invention, preferably, the weight ratio of the shaped alumina calculated as Al2O3 to the silicon source calculated as SiO x is 5 - 9:1 - 5, for example, 5:5, 6:4, 7:3, 8:2, 9:1, and any value within the range composed of any two of these values, preferably 6 - 9:1 - 4; where 1 ≤ x ≤ 2.

[0062] In the present invention, there is a relatively wide selection range for the type of the silicon source. Preferably, the silicon source is a soluble silicate, preferably selected from organosilicates and / or inorganic silicates, including but not limited to at least one of tetraethyl orthosilicate, tetramethylsilane, silica aerogel, and silicon tetrachloride.

[0063] In the present invention, unless otherwise specified, "soluble" means being easily soluble in water, or being easily soluble in water under the action of an auxiliary agent.

[0064] In some embodiments of the present invention, preferably, the basic compound is selected from at least one of ammonium carbonate, ammonium bicarbonate, and ammonia water.

[0065] In some embodiments of the present invention, preferably, the conditions for the second mixing include: the temperature is 20 - 70°C, preferably 25 - 60°C; the rotation speed is 100 - 1000 rpm, preferably 300 - 1000 rpm; the time is 1 - 20 h, preferably 6 - 12 h.

[0066] In the present invention, there is a relatively wide selection range for the method of solid-liquid separation, as long as the second mixture is subjected to solid-liquid separation to obtain the silicon-modified alumina precursor; the methods of solid-liquid separation include but are not limited to filtration, sedimentation, etc.

[0067] In the present invention, the second drying aims to remove the residual moisture in the modified alumina precursor. Preferably, in step (4), the conditions for the second drying include: the temperature is 80 - 120°C, the time is 90 - 110°C; the time is 1 - 20 h, preferably 1 - 12 h.

[0068] In the present invention, there is a relatively wide selection range for the method of the second drying, as long as the conditions for the second drying meet the above limitations. Preferably, the methods of the second drying include but are not limited to spray drying, blast drying, vacuum drying, etc.

[0069] In some embodiments of the present invention, preferably, in step (4), the conditions for the second calcination include: the temperature is 400 - 1000°C, preferably 500 - 900°C; the time is 1 - 10 h, preferably 1 - 5 h. In the present invention, the second calcination is carried out in a muffle furnace or a tube furnace, and the calcination atmosphere is a non-reducing gas, preferably at least one of air, nitrogen, and argon.

[0070] In some embodiments of the present invention, preferably, the dosage ratio of the amino-caprolactam and / or its derivative in g to the solvent in mL is 1:20 - 200, for example, 1:20, 1:40, 1:50, 1:80, 1:100, 1:150, 1:200, and any value within the range composed of any two numerical values, preferably 1:40 - 100.

[0071] In the present invention, the types of the solvents have a relatively wide selection range. Preferably, the solvents are selected from organic solvents, and preferably selected from at least one of organic alcohols, heteroatom-containing cycloalkanes, and aromatic hydrocarbons.

[0072] In a specific embodiment of the present invention, when the solvent is selected from organic alcohols, the organic alcohols are selected from C1-C5 organic alcohols, including but not limited to methanol, ethanol, 1-pentanol, etc.; when the solvent is selected from heteroatom-containing cycloalkanes, the heteroatom-containing cycloalkanes include but not limited to 1,4-dioxane, tetrahydrofuran, etc.; when the solvent is selected from aromatic hydrocarbons, the aromatic hydrocarbons include but not limited to benzene, toluene, etc.

[0073] The second aspect of the present invention provides an application of styrylcaprolactam prepared by the preparation method provided in the first aspect as a polymerization monomer in the preparation of functional nylon-6.

[0074] The third aspect of the present invention provides a functional nylon-6, and the functional nylon-6 contains styrylcaprolactam prepared by the preparation method provided in the first aspect.

[0075] Using styrylcaprolactam prepared by the preparation method provided by the present invention as a polymerization monomer in the preparation of functional nylon-6, the resulting polymer material may have a long branched chain or a network structure and has potential antibacterial, wear-resistant, fluorescent, impact-resistant, flame-retardant and other characteristics.

[0076] According to a particularly preferred embodiment of the present invention, a method for preparing styrylcaprolactam, the preparation method includes: in an inert atmosphere, contacting aminocaprolactam and / or its derivatives, benzaldehyde and a catalyst in a solvent and reacting to obtain styrylcaprolactam; wherein, the temperature of the reaction is 50-70 °C; the solvent is selected from organic alcohols.

[0077] Wherein, the catalyst is selected from silicon-modified alumina with a B acid density of 0-0.5 μmol / g and an L acid density of 100-150 μmol / g, and the silicon-modified alumina includes silicon and alumina; wherein, the silicon-aluminum ratio of the silicon-modified alumina < 1, and silicon is connected to the surface of alumina through Si-O-Al chemical bonds, and adjacent silicon on the surface of the alumina is connected through Si-O-Si chemical bonds; based on the total weight of the silicon-modified alumina, the content of alumina is 60-90 wt%; the content of the silicon in terms of SiO x is 10-40 wt%; wherein, 1 ≤ x ≤ 2.

[0078] The physical property parameters of the catalysts prepared in Preparation Examples 1-9 are all listed in Table 1.

[0079] Preparation Example 1

[0080] (1) 80 g of an aluminum source (pseudo-boehmite), 5 g of an acidic compound aqueous solution (30 wt% dilute nitric acid solution), and 800 mL of water were first mixed in a 1500 mL stirring kettle (temperature: 25°C, rotation speed: 600 rpm, time: 1 h) to obtain a first mixture;

[0081] (2) After spray-drying and shaping the above first mixture (temperature: 100°C, time: 5 h), it was calcined in static air in a muffle furnace at 800°C for 3 h to obtain microspherical shaped alumina;

[0082] (3) The above shaped alumina was dissolved in 800 mL of water. First, a basic compound (ammonia water) was added to adjust the pH to 10, and then 60 g of a silicon source (tetraethyl orthosilicate) was added for a second mixing (temperature: 25°C, rotation speed: 600 rpm, time: 12 h) to obtain a second mixture;

[0083] (4) The above second mixture was subjected to solid-liquid separation. The obtained silicon-modified alumina precursor was dried in a vacuum drying oven at 100°C for 5 h and then calcined in static air in a muffle furnace at 600°C for 3 h to obtain silicon-modified alumina as catalyst S1;

[0084] Among them, the transmission infrared spectrum of the above catalyst S1 is shown in Figure 2(a); as can be seen from Figure 2(a), the signal peaks at wavenumbers 1066 cm -1 and 1160 cm -1 are the vibration absorption peaks of Si-O-Si and Si-O-Al bonds respectively, indicating that silicon in catalyst S1 is bonded to alumina through Si-O-Al chemical bonds, and adjacent silicon on the surface of alumina exists in the form of clusters of SiO x (1 ≤ x ≤ 2).

[0085] Among them, the pyridine infrared characterization spectrum of the above catalyst S1 is as Figure 3 shown. As can be seen from Figure 3 , catalyst S1 has extremely low Bronsted acid sites at a wavenumber of 1540 cm -1 and a certain number of Lewis acid sites at a wavenumber of 1450 cm -1 .

[0086] Among them, the SEM image of the above catalyst S1 is as Figure 4 shown. As can be seen from Figure 4 , the above catalyst S1 is microspherical.

[0087] Preparation Example 2

[0088] (1) First, 80 g of an aluminum source (hydroxyaluminum oxide), 10 g of an acidic compound aqueous solution (10 wt% dilute nitric acid solution), and 800 mL of water were subjected to a first mixing in a 1500 mL stirring kettle (temperature: 20 °C, rotation speed: 400 rpm, time: 1 h) to obtain a first mixture;

[0089] (2) After spray-drying and forming the above first mixture (temperature: 100 °C, time: 5 h), it was calcined in static air in a muffle furnace at 800 °C for 3 h to obtain microspherical formed alumina;

[0090] (3) The above formed alumina was dissolved in 800 mL of water. First, a basic compound (ammonia water) was added to adjust the pH to 12, and then 60 g of a silicon source (tetraethyl orthosilicate) was added for a second mixing (temperature: 25 °C, rotation speed: 400 rpm, time: 8 h) to obtain a second mixture;

[0091] (4) The above second mixture was subjected to solid-liquid separation. The obtained silicon-modified alumina precursor was dried in a vacuum drying oven at 100 °C for 5 h and then calcined in static air in a muffle furnace at 600 °C for 3 h to obtain silicon-modified alumina as catalyst S2.

[0092] Preparation Example 3

[0093] (1) First, 40 g of an aluminum source (pseudoboehmite), 4 g of an acidic compound aqueous solution (20 wt% dilute nitric acid solution), and 800 mL of water were subjected to a first mixing in a 1500 mL stirring kettle (temperature: 30 °C, rotation speed: 400 rpm, time: 1 h) to obtain a first mixture;

[0094] (2) After extrusion molding and vacuum drying of the above first mixture (temperature: 100 °C, time: 5 h), it was calcined in static air in a muffle furnace at 1000 °C for 2 h to obtain strip-shaped formed alumina;

[0095] (3) The above formed alumina was dissolved in 800 mL of water. First, a basic compound (ammonia water) was added to adjust the pH to 12, and then 10 g of a silicon source (tetraethyl orthosilicate) was added for a second mixing (temperature: 40 °C, rotation speed: 400 rpm, time: 6 h) to obtain a second mixture;

[0096] (4) The above second mixture was subjected to solid-liquid separation. The obtained silicon-modified alumina precursor was dried in a vacuum drying oven at 100 °C for 5 h and then calcined in static air in a muffle furnace at 600 °C for 3 h to obtain strip-shaped silicon-modified alumina as catalyst S3.

[0097] Preparation Example 4

[0098] (1) First, 50 g of an aluminum source (pseudo-boehmite), 10 g of an aqueous solution of an acidic compound (20 wt% dilute nitric acid solution), and 800 mL of water were mixed in a 1500 mL stirring kettle for the first time (temperature: 30 °C, rotation speed: 400 rpm, time: 1 h) to obtain a first mixture;

[0099] (2) After subjecting the above first mixture to oil-ammonia dropping sphere forming and air-blowing drying (temperature: 100 °C, time: 5 h), it was calcined in a muffle furnace under static air at 1000 °C for 2 h to obtain spherical formed alumina;

[0100] (3) The above formed alumina was dissolved in 800 mL of water. First, a basic compound (ammonia water) was added to adjust the pH to 10, and then 10 g of a silicon source (silicon tetrachloride) was added for the second mixing (temperature: 25 °C, rotation speed: 400 rpm, time: 6 h) to obtain a second mixture;

[0101] (4) The above second mixture was subjected to solid-liquid separation. The obtained silicon-modified alumina precursor was dried in a hot air drying oven at 100 °C for 5 h and then calcined in a muffle furnace under static air at 800 °C for 3 h to obtain spherical silicon-modified alumina as catalyst S4.

[0102] Preparation Example 5

[0103] (1) First, 80 g of an aluminum source (γ-alumina), 5 g of an aqueous solution of an acidic compound (30 wt% dilute hydrochloric acid solution), and 800 mL of water were mixed in a 1500 mL stirring kettle for the first time (temperature: 30 °C, rotation speed: 800 rpm, time: 1 h) to obtain a first mixture;

[0104] (2) After subjecting the above first mixture to spray drying forming (temperature: 100 °C, time: 5 h), it was calcined in a muffle furnace under static air at 800 °C for 3 h to obtain microspherical formed alumina;

[0105] (3) The above formed alumina was dissolved in 800 mL of water. First, a basic compound (ammonia water) was added to adjust the pH to 12, and then 50 g of a silicon source (silica aerogel) was added for the second mixing (temperature: 25 °C, rotation speed: 400 rpm, time: 12 h) to obtain a second mixture;

[0106] (4) The above second mixture was subjected to solid-liquid separation. The obtained silicon-modified alumina precursor was dried in a hot air drying oven at 100 °C for 5 h and then calcined in a muffle furnace under static air at 800 °C for 3 h to obtain microspherical silicon-modified alumina as catalyst S5.

[0107] Preparation Example 6

[0108] (1) 80 g of aluminum source (pseudoboehmite), 20 g of aqueous acidic compound solution (10 wt% dilute sulfuric acid solution), and 800 mL of water were first mixed in a 1500 mL stirring kettle (temperature: 30 °C, rotation speed: 800 rpm, time: 1 h) to obtain a first mixture;

[0109] (2) After extruding and air-blowing drying the above first mixture (temperature: 100 °C, time: 5 h), it was calcined in a muffle furnace under static air at 800 °C for 3 h to obtain strip-shaped formed alumina;

[0110] (3) The above formed alumina was dissolved in 800 mL of water. First, a basic compound (ammonia water) was added to adjust the pH to 12, and then 30 g of silicon source (tetraethyl orthosilicate) was added for a second mixing (temperature: 60 °C, rotation speed: 800 rpm, time: 6 h) to obtain a second mixture;

[0111] (4) The above second mixture was subjected to solid-liquid separation. The obtained silicon-modified alumina precursor was dried in a vacuum drying oven at 100 °C for 5 h, and then calcined in a muffle furnace under static air at 800 °C for 3 h to obtain strip-shaped silicon-modified alumina as catalyst S6.

[0112] Preparation Example 7

[0113] According to the method of Preparation Example 1, the difference is that

[0114] in step (3), the pH was adjusted to 7;

[0115] Under the same other conditions, microspherical silicon-modified alumina was obtained as catalyst S7.

[0116] Preparation Example 8

[0117] 800 mL of deionized water, 80 g of pseudoboehmite, and 10 g of 10 wt% dilute nitric acid aqueous solution were mixed in a 1500 mL stirring kettle (temperature: 25 °C, rotation speed: 800 rpm, time: 5 h). The obtained mixture was subjected to solid-liquid separation. The obtained solid was spray-dried and then calcined in a muffle furnace under static air at 800 °C for 3 h to obtain microspherical modified alumina as catalyst S8;

[0118] Among them, the transmission infrared spectrum of the above catalyst S8 is shown in Figure 2(b); it can be seen from Figure 2(b) that there are no signal peaks at wavenumbers 1066 cm -1 and 1160 cm -1 , indicating that there is no chemical bonding between silicon and alumina in the above catalyst S8, and there is no chemical bonding between adjacent silicons on the surface of alumina.

[0119] Among them, the pyridine infrared characterization spectrum of the above catalyst S8 is as shown in Figure 3As shown, it can be seen from 3 that the catalyst S8 has a relatively high number of Brønsted acid sites and a certain number of Lewis acid sites.

[0120] Preparation Example 9

[0121] 800 mL of deionized water, 80 g of pseudo-boehmite, and 20 g of 5 wt% dilute nitric acid aqueous solution were mixed in a 1500 mL stirring kettle (temperature: 25 °C, rotation speed: 800 rpm, time: 5 h). Then, 60 g of tetraethyl orthosilicate was added, and ammonia water was added to adjust the pH to 12. The mixture was stirred at 25 °C for 12 h, and the obtained mixture was spray-dried and calcined in static air in a muffle furnace at 800 °C for 3 h to obtain microspherical modified alumina as catalyst S9.

[0122] Among them, the pyridine red external characterization spectrum of the above catalyst S9 is as Figure 3 shown, and it can be seen from Figure 3 that the catalyst S9 has a relatively high number of Brønsted acid sites and a certain number of Lewis acid sites.

[0123] Table 1

[0124]

[0125] Note: * - The silicon content is calculated as SiO x where 1 ≤ x ≤ 2.

[0126] Continued Table 1

[0127] <![CDATA[Specific surface area, m 2 / g]]> Average pore diameter, nm Attrition index, % Crushing strength, N / cm Preparation Example 1 194.7 20.8 1.7 129.3 Preparation Example 2 163.3 15.7 4.3 105.3 Preparation Example 3 123.3 20.8 9.8 71.5 Preparation Example 4 108.2 22.7 14.2 78.3 Preparation Example 5 182.6 23.9 18.7 80.3 Preparation Example 6 188.4 26.9 3.2 108.1 Preparation Example 7 155.2 12.3 8.3 55.1 Preparation Example 8 112.2 14.5 33.8 35.4 Preparation Example 9 80.1 7.2 19.2 56.8

[0128] From the results in Table 1, it can be seen that compared with Preparation Examples 8 - 9, the silicon-modified alumina prepared in Examples 1 - 7 has both a low Brønsted acid density, a high Lewis acid density, a low attrition index, a high crushing strength, a high specific surface area, and a low average pore diameter. That is, the silicon-modified alumina provided by the present invention has a low Brønsted acid density, a high Lewis acid density, wear resistance, high stability, and an excellent pore structure.

[0129] Example 1

[0130] In the presence of 50 mL of methanol and 0.2 g of catalyst S1, 0.5 g of amino-caprolactam and 0.3 g of benzaldehyde were reacted in a batch high-pressure reactor. Among them, the reaction conditions included: temperature 60 °C, nitrogen pressure 0.6 MPa, time 1 h, to obtain a reaction product, where the target product was styryl amino-caprolactam; among them, the reaction conditions and process parameters are all listed in Table 2; the catalytic reaction results were analyzed by gas chromatography, and the test results are listed in Table 3.

[0131] Specifically, for the detection of the reaction product, the reaction solution and the catalyst were separated by filtration. A certain amount of n-decane was added as an internal standard, and the internal standard was mixed evenly with the reaction filtrate, followed by gas phase analysis and quantification (Agilent GC 7890B; separation column: PONA column (0.32 mm × 30 m);

[0132] Calculation of the conversion rate of aminocaprolactam:

[0133]

[0134] Among them, the mass of the converted aminocaprolactam = the mass of aminocaprolactam - the remaining mass of aminocaprolactam.

[0135] Calculation of the selectivity of styryl aminocaprolactam (selectivity is defined as the ratio of the molar amount of the product to the molar amount of the converted raw material under the same unit representation):

[0136]

[0137] Calculation of the yield of styryl aminocaprolactam:

[0138] The yield of styryl aminocaprolactam = the conversion rate of aminocaprolactam × the selectivity of styryl aminocaprolactam × 100%.

[0139] Examples 2 - 9

[0140] According to Example 1, the difference is that the types of catalysts and process parameters are different, that is,

[0141] According to the reaction conditions and process parameters in Table 2 respectively, the test results obtained are all listed in Table 3.

[0142] Comparative Examples 1 - 2

[0143] According to Example 1, the difference is that the types of catalysts and process parameters are different, that is, according to the reaction conditions and process parameters in Table 2 respectively, the test results obtained are all listed in Table 3.

[0144] Table 2

[0145]

[0146] Table 3

[0147]

[0148] It can be seen from the data in Tables 2 - 3 that compared with Comparative Examples 1 - 2, Examples 1 - 9 using the preparation method provided by the present invention, especially using a specific catalyst, are more conducive to improving the selectivity of styryl aminocaprolactam, and thus improving the yield of styryl aminocaprolactam.

[0149] By comparing Examples 1 - 7, it can be seen that when methanol is used as the solvent, the preparation method provided by the present invention is more conducive to improving the selectivity of styrylaminocaprolactam under the reaction conditions of temperature, that is, the reaction temperature is in the range of 50 - 70 °C.

[0150] Examples 10 - 14

[0151] According to the method of Example 1, the difference is that

[0152] According to the reaction conditions and process parameters in Table 4 respectively, the test results obtained are all listed in Table 5.

[0153] Table 4

[0154]

[0155] Table 5

[0156]

[0157]

[0158] Based on the data in Tables 4 - 5 above, it can be seen that under the same process parameter conditions, compared with Examples 10 - 14, Example 1 uses methanol as the solvent and has a higher selectivity of the target product, and thus a higher yield of the target product is obtained.

[0159] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited thereto. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solutions of the present invention, including any other suitable combination of each technical feature. These simple modifications and combinations should also be regarded as the content disclosed by the present invention and fall within the protection scope of the present invention.

Claims

1. A method for preparing styryl aminocaprolactam, characterized in that, The preparation method includes: in an inert atmosphere, contacting and reacting aminocaprolactam and / or its derivatives, benzaldehyde and a catalyst in a solvent to obtain styryl aminocaprolactam; wherein, the temperature of the reaction is 30-120 °C.

2. The preparation method according to claim 1, wherein The conditions of the reaction include: the temperature is 50-100 °C, preferably 50-70 °C; the pressure is 0.1-10 MPa, preferably 0.5-3 MPa; the time is 0.5-5 h, preferably 1-3 h; and / or, the inert atmosphere is selected from a nitrogen atmosphere, a helium atmosphere, and an argon atmosphere.

3. The preparation method according to claim 1 or 2, wherein The mass ratio of the aminocaprolactam and / or its derivatives to benzaldehyde is 1:0.2-4, preferably 1:0.5-1.2; and / or, the aminocaprolactam and / or its derivatives are selected from aminocaprolactam and / or aminocaprolactam salts.

4. The preparation method according to any one of claims 1-3, wherein, The mass ratio of the aminocaprolactam and / or its derivatives to the catalyst is 1:0.1-10, preferably 1:0.1-5, more preferably 1:0.5-2.

5. The preparation method according to any one of claims 1-4, wherein, The catalyst is selected from modified oxides; Preferably, the B acid density of the modified oxide is ≤2 μmol / g, preferably 0-2 μmol / g, further preferably 0-1.4 μmol / g, more preferably 0-0.5 μmol / g; the L acid density is 50-300 μmol / g, preferably 90-200 μmol / g, more preferably 100-150 μmol / g.

6. The preparation method according to claim 5, wherein, The catalyst is selected from silicon-modified alumina with a B acid density ≤2 μmol / g and an L acid density of 50-300 μmol / g, and the silicon-modified alumina includes silicon and alumina; wherein, the silicon-aluminum ratio of the silicon-modified alumina is <1, and silicon is connected to the surface of alumina through Si-O-Al chemical bonds, and adjacent silicon on the surface of the alumina is connected through Si-O-Si chemical bonds; Preferably, based on the total weight of the silicon-modified alumina, the content of the alumina is 50-90 wt%, preferably 60-90 wt%; in terms of SiO x the content of the silicon is 10-50 wt%, preferably 10-40 wt%; wherein, 1≤x≤2; Preferably, the specific surface area of the silicon-modified alumina is 100-220 m 2 / g, preferably 120-200 m 2 / g; the average pore diameter is 10-30 nm, preferably 15-25 nm; the attrition index is 1-20%, preferably 1-15%; the crush strength is 50-150 N / cm, preferably 70-130 N / cm.

7. The preparation method according to claim 6, wherein, The silicon-modified alumina is prepared by the following method: (1) First mixing an aluminum source, an acidic compound and water to obtain a first mixture; (2) Successively shaping, first drying and first calcining the first mixture to obtain shaped alumina; (3) Dissolving the shaped alumina in water, first adding a basic compound to adjust the pH to 7-12, and then adding a silicon source for second mixing to obtain a second mixture; (4) Separating the solid and liquid of the second mixture, and successively performing second drying and second calcining on the obtained silicon-modified alumina precursor to obtain the silicon-modified alumina.

8. The preparation method according to any one of claims 1-7, wherein The dosage ratio of the aminocaprolactam and / or its derivatives in g to the solvent in mL is 1:20-200, preferably 1:40-100; Preferably, the solvent is selected from organic compounds, preferably at least one of organic alcohols, heteroatom-containing cycloalkanes and aromatic hydrocarbons, more preferably organic alcohols.

9. Use of the styryl aminocaprolactam prepared by the preparation method according to any one of claims 1-8 as a polymerization monomer in the preparation of functional nylon-6.

10. A functional nylon-6, characterized in that, The functional nylon-6 contains the styryl aminocaprolactam prepared by the preparation method according to any one of claims 1-8.

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