Synthetic method and application of functional caprolactam and functional nylon-6

Abstract

The invention relates to the technical field of organic synthesis, in particular to a synthesis method and application of functional caprolactam and functional nylon-6. The synthesis method comprises the following steps: in the presence of a catalyst and a solvent, enabling amino caprolactam and / or a derivative thereof to contact and react with benzaldehyde, so as to obtain functional caprolactam which is bis (benzyl) amino caprolactam, wherein the reaction conditions are as follows: the temperature is 150-350 DEG C; the hydrogen pressure is 0.1 to 10 MPa; the time is 5-15 hours. The synthesis method not only has the advantages of high reaction efficiency, high catalytic efficiency, adjustable target product selectivity and the like, but also simplifies process conditions, and realizes green large-scale production.

Description

Technical Field

[0001] The present invention relates to the technical field of organic synthesis, and particularly relates to a method for synthesizing a functional caprolactam and its application, 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. There is a large market demand for nylon materials with antibacterial, wear-resistant, and impact-resistant properties, but due to problems in material properties, manufacturing costs, etc., these functional materials are mostly 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 intrinsically antibacterial, wear-resistant, and other functional nylon materials at the polymerization monomer level.

[0003] CN104629045A discloses a method for synthesizing a bis(benzyl) derivative-functionalized caprolactam, which includes: α-aminocaprolactam and benzyl chloride are co-dissolved in acetonitrile, and under certain heating conditions, they can react to form a bis(benzyl) derivative-functionalized caprolactam. Similarly, CN104387323A discloses a method for obtaining a bis(benzyl) derivative-functionalized caprolactam using lysine hydrochloride and benzyl chloride as raw materials under the condition of heating and refluxing in methanol.

[0004] WO2020197991A1 discloses a method for synthesizing a bis(benzyl) derivative-functionalized caprolactam using benzaldehyde as a reactant. This method uses α-aminocaprolactam and benzaldehyde as reactants and sodium triacetoxyborohydride as a hydrogenation reagent to obtain a bis(benzyl) derivative-functionalized caprolactam in 1,2-dichloroethane; or using sodium bicarbonate as a hydrogenation reagent, a bis(benzyl) derivative-functionalized caprolactam can also be obtained in water.

[0005] Although the above research has promoted the development of the synthesis route of aryl-derived functional caprolactam to a certain extent, there are the following problems: 1. Halides have strong toxicity and poor chemical stability, which will cause serious pollution to the environment; 2. The efficiency of organic reactions is low, and the reaction system is not green, with a large environmental protection pressure, which is not conducive to the scale production of target products; 3. Organoborohydrides have high costs and poor stability, and inorganic hydrides will generate inorganic salts after the reaction, with low added value, and neither of them is an ideal hydrogenation reagent.

[0006] Therefore, developing highly 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

[0007] The object of the present invention is to overcome the problems existing in the prior art for preparing aromatic functional caprolactam, such as strong toxicity of raw materials, harsh reaction conditions, low catalytic efficiency, low reaction efficiency, low safety, etc., and to provide a method for synthesizing functional caprolactam and its application, and a functional nylon-6. The synthesis method not only has advantages such as high reaction efficiency, high catalytic efficiency and adjustable selectivity of the target product, but also simplifies the process conditions and realizes green large-scale production.

[0008] To achieve the above object, in the first aspect, the present invention provides a method for synthesizing functional caprolactam, the synthesis method comprising: in the presence of a catalyst and a solvent, contacting aminocaprolactam and / or its derivative with benzaldehyde and reacting to obtain the functional caprolactam as bis(benzylamino)caprolactam;

[0009] Wherein, the conditions of the reaction include: the temperature is 150-350 °C; the hydrogen pressure is 0.1-10 MPa; the time is 5-15 h.

[0010] Preferably, the mass ratio of the aminocaprolactam and / or its derivative to benzaldehyde is 1:0.2-8, preferably 1:0.4-3.

[0011] Preferably, the mass ratio of the aminocaprolactam and / or its derivative to the catalyst is 1:0.1-10, preferably 1:0.1-5, more preferably 1:0.5-2.

[0012] Preferably, the catalyst comprises a carrier and an active component supported on the carrier.

[0013] Preferably, the carrier 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 comprises silicon and alumina; wherein, the silicon-aluminum ratio of the silicon-modified alumina is <1, and the silicon is connected to the surface of the alumina through Si-O-Al chemical bonds, and adjacent silicons on the surface of the alumina are connected through Si-O-Si chemical bonds.

[0014] In the second aspect, the present invention provides an application of the functional caprolactam prepared by the synthesis method provided in the first aspect as a polymerization monomer in the preparation of functional nylon-6.

[0015] In the third aspect, the present invention provides a functional nylon-6, and the functional nylon-6 contains the functional caprolactam prepared by the synthesis method provided in the first aspect.

[0016] Compared with the prior art, the present invention has the following advantages:

[0017] (1) The synthetic method of functional caprolactam provided by the present invention uses amino caprolactam and / or its derivatives and benzaldehyde as raw materials, combined with a catalyst and a solvent, and can efficiently obtain a high raw material conversion rate and a high target product selectivity under certain reaction conditions; in particular, by adjusting the carrier and active components in the catalyst, defining the B acid density and L acid density of a specific carrier, and the dispersion degree of a specific active component, the catalytic efficiency can be further improved; at the same time, this synthetic method also simplifies the process flow, is easy to operate, environmentally friendly, and convenient for industrial production;

[0018] (2) The functional caprolactam prepared by the synthetic method provided by the present invention is used as a polymerization monomer in the preparation of functional nylon-6 materials such as antibacterial, luminescent, flame-retardant, wear-resistant, and elastomer materials. Description of the Drawings

[0019] Figure 1 is the synthetic route of the functional caprolactam provided by the present invention;

[0020] Figure 2(a) is the transmission infrared spectrum of the carrier S1 prepared in Preparation Example 1, and Figure 2(b) is the transmission infrared spectrum of the carrier S8 prepared in Preparation Example 8. Among them, the signal peaks at the wave numbers of 1066 cm -1 and 1160 cm -1 are the vibration absorption peaks of the Si-O-Si and Si-O-Al bonds, respectively;

[0021] Figure 3 is the pyridine infrared characterization spectrum of the carrier S1 prepared in Preparation Example 1 and the carriers S8-S9 prepared in Preparation Examples 8-9. Among them, the absorption peak at the wave number of 1540 cm -1 indicates the B acid sites on the surface of the carrier, and the absorption peak at the wave number of 1450 cm -1 indicates the L acid sites on the surface of the carrier;

[0022] Figure 4 is the TEM image of the catalyst Pd / S1 prepared in Preparation Example 1. Detailed Embodiments

[0023] In the ranges disclosed herein, the endpoints and any values are not limited to the exact ranges or values, and 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.

[0024] In the present invention, unless otherwise specified, "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 sintering", "second sintering" and "third sintering", "first", "second" and "third" are only used to indicate that these are not the same sintering.

[0025] In a first aspect of the present invention, there is provided a method for synthesizing a functional caprolactam, the synthesis method comprising: contacting and reacting aminocaprolactam and / or its derivatives with benzaldehyde in the presence of a catalyst and a solvent to obtain a functional caprolactam which is bis(benzylamino)caprolactam;

[0026] Wherein, the conditions of the reaction include: the temperature is 150 - 350 °C; the hydrogen pressure is 0.1 - 10 MPa; the time is 5 - 15 h.

[0027] In some embodiments of the present invention, as Figure 1 shown, 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 obtained functional caprolactam includes: the lactam ring of caprolactam, α-amino, and two benzyl groups derived from α-amino. In the present invention, the functional caprolactam is bis(benzylamino)caprolactam.

[0028] In some embodiments of the present invention, the conditions of the reaction include: the temperature is 150 - 350 °C; the hydrogen pressure is 0.1 - 10 MPa; the time is 5 - 15 h; preferably, the conditions of the reaction include: the temperature is 200 - 300 °C, more preferably 220 - 280 °C; the hydrogen pressure is 1 - 5 MPa; the time is 8 - 12 h. In the present invention, unless otherwise specified, the pressure refers to the gauge pressure.

[0029] In some embodiments of the present invention, preferably, the mass ratio of the aminocaprolactam and / or its derivatives to benzaldehyde is 1:0.2 - 8, for example, 1:0.2, 1:0.4, 1:0.45, 1:0.5, 1:0.55, 1:0.6, 1:0.8, 1:1, 1:1.5, 1:2, 1:2.5, 1:3, 1:4, 1:5, 1:6, 1:7, 1:8, and any value within the range composed of any two numerical values, preferably 1:0.4 - 3. Using the preferred mass ratio range is more conducive to improving the selectivity of the target product and thus increasing the yield of the target product.

[0030] In the present invention, unless otherwise specified, the aminocaprolactam and / or its derivatives are selected from aminocaprolactam and / or aminocaprolactam derivatives.

[0031] In some embodiments of the present invention, preferably, the amino-caprolactam and / or its derivatives are selected from amino-caprolactam and / or amino-caprolactam salts. In the present invention, the amino-caprolactam salts include, but are not limited to, at least one of hydrochloride, sulfate, and nitrate.

[0032] In some embodiments of the present invention, more preferably, the amino-caprolactam and / or its derivatives are 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.

[0033] In some embodiments of the present invention, preferably, the mass ratio of the amino-caprolactam and / or its derivatives 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 values, preferably 1:0.5 - 5, more preferably 1:0.5 - 2. A mass ratio within the above range is more conducive to improving the conversion rate of raw materials and thus increasing the yield of the target product.

[0034] In the present invention, the type of the catalyst is a conventional catalyst in the art, that is, a shaped catalyst. Preferably, the catalyst includes a carrier and an active component supported on the carrier; more preferably, based on the total weight of the catalyst, the content of the active component is 0.1 - 15 wt%, preferably 0.5 - 10 wt%.

[0035] In the present invention, without special circumstances, the total weight of the catalyst = the weight of the active component + the weight of the carrier. That is, based on the total weight of the catalyst, the content of the carrier is 85 - 99.9 wt%, preferably 90 - 99.5 wt%.

[0036] In some embodiments of the present invention, preferably, the active component is selected from at least one of Pt, Pd, Rh, Ir, Ru, and Ni, preferably Pt and / or Pd.

[0037] In some embodiments of the present invention, preferably, the dispersion degree of the active component ≥ 20%, for example, 20%, 30%, 40%, 50%, 60%, 80%, and any value within the range composed of any two values, preferably 20 - 80%.

[0038] In some embodiments of the present invention, preferably, the carrier is selected from at least one of molecular sieves, oxides, and modified oxides. Among them, the molecular sieves include, but are not limited to, SAPO-34 molecular sieve, TS-1 molecular sieve, HY molecular sieve, etc.; the oxides include, but are not limited to, SiO2, Al2O3, TiO2, ZrO2, CeO2, etc.; the modified oxides include, but are not limited to, silicon-modified alumina.

[0039] In some embodiments of the present invention, preferably, the B acid density of the modified oxide is ≤ 2 μmol / g, preferably 0 - 2 μmol / g, more preferably 0 - 1.4 μmol / g, and even more preferably 0 - 0.5 μmol / g; the L acid density of the modified oxide is 50 - 300 μmol / g, preferably 90 - 200 μmol / g, and more preferably 100 - 150 μmol / g.

[0040] In a specific embodiment of the present invention, preferably, the modified oxide is silicon-modified alumina with a B acid density ≤ 2 μmol / g and an L acid density selected from 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.

[0041] 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 field. 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 abrasion 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.

[0042] In the present invention, without special instructions, 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.

[0043] In the present invention, without special instructions, the B acid density refers to acid density; the L acid density refers to Lewis acid density.

[0044] 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 silicon-modified alumina indicated at the wavenumber of 1540 cm -1 in the pyridine infrared spectrum (unit: μmol) / the mass of silicon-modified alumina (unit: 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 silicon-modified alumina indicated at the wavenumber of 1450 cm -1 in the pyridine infrared spectrum (unit: μmol) / the mass of silicon-modified alumina (unit: g).

[0045] 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 of these values. Preferably, it is 0 - 1.4 μmol / g, and more preferably 0 - 0.5 μmol / g.

[0046] 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 of these values. Preferably, it is 90 - 200 μmol / g, and more preferably 100 - 150 μmol / g.

[0047] In the present invention, the L acid of the silicon-modified alumina can promote the reaction between the aldehyde group of benzaldehyde and the α-amino group of aminocaprolactam to obtain the target product; the reduction or elimination of the B acid of the silicon-modified alumina can inhibit side reactions such as the alcoholysis ring-opening of aminocaprolactam, that is, the reduction of 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 support can effectively improve the selectivity of the target product.

[0048] In some embodiments of the present invention, 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.

[0049] In the present invention, unless otherwise specified, the specific surface area parameter is measured by a fully automatic isothermal adsorption instrument; the average pore diameter parameter is obtained by a fully automatic isothermal adsorption instrument in combination with the BJH model; the attrition index parameter is measured by an attrition index analyzer; the crush strength parameter is measured by a particle strength tester.

[0050] In the present invention, unless otherwise specified, in addition to silicon and alumina, the silicon-modified alumina contains no other impurities, 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%; the content of silicon calculated as SiO x is 10 - 50 wt%, where 1 ≤ x ≤ 2.

[0051] In some embodiments of the present invention, preferably, the shape of the silicon-modified alumina is selected from spherical and strip-shaped; among them, the spherical shape includes but is not limited to microspherical and small spherical.

[0052] In some embodiments of the present invention, preferably, the alumina is selected from γ-alumina. Under the preferred conditions, it is more conducive to improving the activity of the silicon-modified alumina.

[0053] 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:

[0054] (1) First mix an aluminum source, an acidic compound and water to obtain a first mixture;

[0055] (2) Successively form, first dry and first calcine the first mixture to obtain shaped alumina;

[0056] (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;

[0057] (4) Perform solid-liquid separation on the second mixture, and successively perform second drying and second calcination on the obtained silicon-modified alumina precursor to obtain the silicon-modified alumina.

[0058] 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, the acidic compound and water only needs to meet the above limitations.

[0059] In the present invention, there is a wide selection range for the type of the aluminum source. Preferably, the aluminum source is a soluble aluminum salt, including but not limited to γ-aluminum oxide, hydroxyaluminum oxide, pseudoboehmite, aluminum chloride, aluminum nitrate, etc. When the aluminum source is selected from γ-aluminum oxide, steps (1)-(2) acidify the surface of the powdered aluminum oxide to form a hydrated hydroxyl state, which is convenient for subsequent addition of the basic compound and the silicon source for silicon modification.

[0060] In the present invention, there is a wide selection range 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. Preferably, the concentration of the acidic compound in the acidic compound solution is 1-50 wt%.

[0061] In the present invention, there is a wide selection range for the first mixing method, as long as the aluminum source, the acidic compound and water are mixed. 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.

[0062] In the present invention, there is a wide selection range for the forming method. Preferably, in step (2), the forming methods include but not limited to oil ammonia dropping ball forming, spray drying forming, extrusion forming.

[0063] 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.

[0064] In the present invention, there is a wide selection range for the first drying method, as long as the conditions for the first drying meet the above limitations. Preferably, the first drying methods include but not limited to spray drying, air drying, vacuum drying, etc.

[0065] 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 tubular furnace, and the calcination atmosphere is a non-reducing gas, preferably selected from at least one of air, nitrogen, and argon.

[0066] 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 hydroxyhydrated silicon.

[0067] 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 numerical values, preferably 10.5 - 11.5.

[0068] 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; wherein, 1 ≤ x ≤ 2.

[0069] In the present invention, there is a wide selection range for the type of the silicon source. Preferably, the silicon source is a soluble silicate, preferably selected from organic silicates and / or inorganic silicates, including but not limited to at least one of tetraethyl orthosilicate, tetramethylsilane, silica aerogel, and silicon tetrachloride.

[0070] In the present invention, without special instructions, soluble means easily soluble in water, or easily soluble in water under the action of an auxiliary agent.

[0071] In some embodiments of the present invention, preferably, the alkaline compound is selected from at least one of ammonium carbonate, ammonium bicarbonate, and ammonia water.

[0072] 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.

[0073] In the present invention, there is a wide selection range for the method of solid-liquid separation, as long as the second mixture is subjected to solid-liquid separation to obtain a silicon-modified alumina precursor; the methods of solid-liquid separation include but are not limited to filtration, sedimentation, etc.

[0074] In the present invention, the second drying aims to remove the residual moisture in the silicon-modified alumina precursor. Preferably, in step (4), the conditions for the second drying include: the temperature is 80 - 120 °C, and the time is 90 - 110 °C; the time is 1 - 20 h, preferably 1 - 12 h.

[0075] In the present invention, there is a wide range of choices for the method of the second drying, as long as the conditions for the second drying meet the above limitations. Preferably, the methods for the second drying include, but are not limited to, spray drying, blast drying, vacuum drying, etc.

[0076] 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 selected from at least one of air, nitrogen, and argon.

[0077] In the present invention, there is a wide range of choices for the preparation method of the catalyst, as long as the catalyst meets the above limitations. Preferably, the catalyst is prepared by the following method: a soluble metal salt is loaded on the surface of the carrier, and the obtained catalyst precursor is sequentially subjected to a third drying and a third calcination to obtain the catalyst.

[0078] In some embodiments of the present invention, preferably, the loading amount of the soluble metal salt in terms of the metal element is 0.1 - 15 wt%, preferably 0.5 - 10 wt%.

[0079] In the present invention, there is a wide range of choices for the loading method, as long as the loading amount of the soluble metal salt meets the above limitations. Preferably, the loading method is selected from the impregnation method and the deposition-precipitation method.

[0080] In the present invention, when the loading method is the impregnation method, an impregnation solution containing the soluble metal salt needs to be prepared. Depending on the amount of the impregnation solution used, the impregnation method is selected from the excess impregnation method and the saturation impregnation method; depending on the way of realizing the impregnation, the impregnation method is selected from the immersion impregnation method and the spray impregnation method. It is easy for those skilled in the art to understand that by adjusting and controlling the concentration, amount of the impregnation solution or the amount of the carrier, a catalyst with a specific loading amount can be obtained.

[0081] In some embodiments of the present invention, when the loading method is the impregnation method, the solvents in the impregnation solution containing the soluble metal salt include, but are not limited to, water, ammonia water, and hydrochloric acid. The present invention does not limit the concentration of the soluble metal salt in the impregnation solution containing the soluble metal salt.

[0082] In some embodiments of the present invention, when the method for the load is the deposition precipitation method, the solvent in the impregnation solution containing the soluble metal salt includes but is not limited to water. The present invention does not limit the concentration of the soluble metal salt in the impregnation solution containing the soluble metal salt.

[0083] In some embodiments of the present invention, preferably, the soluble metal salt is selected from hydrochlorides, sulfates, nitrates, and acetates containing at least one of Pt, Pd, Rh, Ir, Ru, and Ni, and is preferably selected from nitrates, sulfates, and nitrates containing Pt and / or Pd. In the present invention, the soluble metal salt includes but is not limited to Ni(NO3)2, PdCl2, H2PtCl6, Pd(NO3)2, Pd(NH3)4Cl2, Pd(NH3)4(NO3)2, RuCl3, and iridium acetate.

[0084] In some embodiments of the present invention, preferably, the conditions for the third drying include: the temperature is 80 - 120 °C, and the time is 90 - 110 °C; the time is 1 - 20 h, preferably 1 - 12 h.

[0085] In the present invention, there is a wide selection range for the method of the third drying, as long as the conditions for the third drying meet the above limitations. Preferably, the method of the third drying includes but is not limited to spray drying, air drying, vacuum drying, etc.

[0086] In some embodiments of the present invention, preferably, the conditions for the third calcination include: the temperature is 400 - 800 °C, and the time is 450 - 750 °C; the time is 1 - 10 h, preferably 1 - 5 h. In the present invention, the third calcination is carried out in a muffle furnace or a tube furnace, and the calcination atmosphere is a non-reducing gas, preferably selected from at least one of air, nitrogen, and argon.

[0087] In some embodiments of the present invention, preferably, the dosage ratio of the aminocaprolactam 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.

[0088] In the present invention, there is a wide selection range for the type of the solvent. Preferably, the solvent is selected from organic solvents, and is preferably selected from at least one of organic alcohols, heteroatom-containing cycloalkanes, and aromatic hydrocarbons.

[0089] 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, isopropanol, 1-pentanol, etc.; when the solvent is selected from heteroatom-containing cycloalkanes, the heteroatom-containing cycloalkanes include but are not limited to 1,4-dioxane, tetrahydrofuran, etc.; when the solvent is selected from aromatic hydrocarbons, the aromatic hydrocarbons include but are not limited to benzene, toluene, etc.

[0090] A preferred method for preparing a supported catalyst provided by the present invention, the preparation method comprising:

[0091] (1) First mix an aluminum source, an acidic compound and water to obtain a first mixture;

[0092] (2) Shape, first dry and first calcine the first mixture in sequence to obtain shaped alumina;

[0093] (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;

[0094] (4) Perform solid-liquid separation on the second mixture, and the obtained silicon-modified alumina precursor is sequentially subjected to second drying and second calcination to obtain silicon-modified alumina;

[0095] (5) Load a soluble metal salt on the surface of the carrier, and the obtained catalyst precursor is sequentially subjected to third drying and third calcination to obtain a catalyst;

[0096] Wherein, the B acid density of the silicon-modified alumina is ≤2 μmol / g, preferably 0-2 μmol / g, more preferably 0-1.4 μmol / g, and most 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.

[0097] The second aspect of the present invention provides the application of the functional caprolactam prepared by the synthesis method provided in the first aspect as a polymerization monomer in the preparation of functional nylon-6.

[0098] The third aspect of the present invention provides a functional nylon-6, which contains the functional caprolactam prepared by the synthesis method provided in the first aspect.

[0099] Using the functional caprolactam prepared by the synthesis method provided by the present invention as a polymerization monomer and applying it in the preparation of functional nylon-6, the obtained 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.

[0100] According to a particularly preferred embodiment of the present invention, a method for synthesizing a functional caprolactam, the synthesis method comprising: in the presence of a catalyst and a solvent, contacting aminocaprolactam and / or its derivatives with benzaldehyde and reacting to obtain a functional caprolactam which is bis(benzylamino)caprolactam;

[0101] Wherein, the reaction conditions include: temperature is 220 - 280 °C; hydrogen pressure is 1 - 5 MPa; time is 8 - 12 h;

[0102] Wherein, the catalyst includes a carrier and an active component supported on the carrier, the carrier 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, the silicon-modified alumina includes silicon and alumina; wherein, the silicon-aluminum ratio of the silicon-modified alumina < 1, 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; based on the total weight of the catalyst, the content of the active component is 0.5 - 10 wt%.

[0103] The present invention will be described in detail below through examples.

[0104] The physical property parameters of the catalysts prepared in Preparation Examples 1 - 15 are all listed in Table 1.

[0105] Preparation Example 1

[0106] (1) First mix 80 g of an aluminum source (pseudo-boehmite), 5 g of an acidic compound (30 wt% dilute nitric acid) and 800 mL of water in a 1500 mL stirring kettle (temperature is 25 °C, rotation speed is 600 rpm, time is 1 h) to obtain a first mixture;

[0107] (2) After spray-drying and forming the above first mixture (temperature is 100 °C, time is 5 h), calcine it in a muffle furnace in static air at 800 °C for 3 h to obtain microspherical formed alumina;

[0108] (3) Dissolve the above formed alumina in 800 mL of water, first add a basic compound (ammonia water) to adjust the pH to 10, and then add 60 g of a silicon source (tetraethyl orthosilicate) for a second mixture (temperature is 25 °C, rotation speed is 600 rpm, time is 12 h) to obtain a second mixture;

[0109] (4) Separate the solid and liquid of the above second mixture, and after drying the obtained silicon-modified alumina precursor in a vacuum drying oven at 100 °C for 5 h, calcine it in a muffle furnace in static air at 600 °C for 3 h to obtain microspherical silicon-modified alumina as carrier S1;

[0110] (5) The Pd(NH3)4Cl2 solution prepared with 30 wt% ammonia water was impregnated onto the surface of the above-mentioned support S1 by the excess impregnation method to obtain a catalyst precursor with a Pd loading of 10 wt%. After drying in a vacuum drying oven at 100 °C for 5 h, it was calcined in a muffle furnace under static air at 500 °C for 3 h to obtain the microspherical catalyst Pd / S1.

[0111] Among them, the transmission infrared spectrum of the above-mentioned support 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 the silicon-modified alumina is bonded to alumina through chemical bonds, and adjacent silicon on the surface of alumina exists in the form of clusters of SiO x (1 ≤ x ≤ 2).

[0112] Among them, the pyridine infrared characterization spectrum of the above-mentioned support S1 is as Figure 3 shown. As can be Figure 3 seen, the support S1 has extremely low Brønsted acid sites at a wavenumber of 1540 cm -1 and a certain number of Lewis acid sites at a wavenumber of 1450 cm -1 .

[0113] Among them, the TEM image of the catalyst Pd / S1 is as Figure 4 shown. As can be Figure 4 seen, the active component Pd in the catalyst Pd / S1 is uniformly loaded on the surface of the support.

[0114] Preparation Example 2

[0115] (1) 50 g of an aluminum source (pseudo-boehmite), 10 g of an acidic compound (5 wt% dilute nitric acid), and 800 mL of water were first mixed in a 1500 mL stirring kettle (temperature: 20 °C, rotation speed: 500 rpm, time: 1 h) to obtain a first mixture;

[0116] (2) After spray-drying and shaping the above-mentioned first mixture (temperature: 100 °C, time: 5 h), it was calcined in a muffle furnace under static air at 1000 °C for 1 h to obtain microspherical shaped alumina;

[0117] (3) The above-mentioned shaped alumina was dissolved in 800 mL of water. First, a basic compound (ammonium bicarbonate) was added to adjust the pH to 9, and then 50 g of a silicon source (silica aerogel) was added for a second mixing (temperature: 25 °C, rotation speed: 500 rpm, time: 8 h) to obtain a second mixture;

[0118] (4) The above-mentioned second mixture is subjected to solid-liquid separation. After the obtained silicon-modified alumina precursor is dried in a vacuum drying oven at 100 °C for 5 h, it is calcined in a tubular furnace under a nitrogen atmosphere at 800 °C for 2 h to obtain microspherical silicon-modified alumina as carrier S2;

[0119] (5) A Ni(NO3)2 solution is prepared with deionized water and impregnated onto the surface of the above-mentioned carrier S2 by the excess impregnation method to obtain a catalyst precursor with a Ni loading of 6 wt%. After drying in a vacuum drying oven at 100 °C for 5 h, it is calcined in a muffle furnace under static air at 500 °C for 3 h to obtain microspherical catalyst Ni / S2.

[0120] Preparation Example 3

[0121] (1) 20 g of an aluminum source (hydroxyaluminum oxide), 1 g of an acidic compound (30 wt% dilute hydrochloric acid), and 800 mL of water are subjected to a first mixing in a 1500 mL stirring kettle (temperature is 30 °C, rotation speed is 500 rpm, time is 1 h) to obtain a first mixture;

[0122] (2) The above-mentioned first mixture is subjected to extrusion molding and blast drying (temperature is 100 °C, time is 5 h), and then calcined in a muffle furnace under static air at 800 °C for 3 h to obtain strip-shaped formed alumina;

[0123] (3) The above-mentioned formed alumina is dissolved in 800 mL of water. First, an alkaline compound (ammonia water) is added to adjust the pH to 10, and then 56 g of a silicon source (silicon tetrachloride) is added for a second mixing (temperature is 50 °C, rotation speed is 500 rpm, time is 10 h) to obtain a second mixture;

[0124] (4) The above-mentioned second mixture is subjected to solid-liquid separation. After the obtained silicon-modified alumina precursor is dried in a blast drying oven at 100 °C for 5 h, it is calcined in a tubular furnace under a nitrogen atmosphere at 600 °C for 6 h to obtain strip-shaped silicon-modified alumina as carrier S3;

[0125] (5) An H2PtCl6 solution is prepared with deionized water and impregnated onto the surface of the above-mentioned carrier S3 by the saturated impregnation method to obtain a catalyst precursor with a Pt loading of 2 wt%. After drying in a vacuum drying oven at 100 °C for 5 h, it is calcined in a tubular furnace under an H2 / N2 atmosphere at 500 °C for 3 h to obtain strip-shaped catalyst Pt / S3.

[0126] Preparation Example 4

[0127] (1) 50 g of an aluminum source (pseudoboehmite), 2 g of an acidic compound (50 wt% dilute phosphoric acid), and 800 mL of water are subjected to a first mixing in a 1500 mL stirring kettle (temperature is 25 °C, rotation speed is 800 rpm, time is 1 h) to obtain a first mixture;

[0128] (2) After subjecting the above first mixture to drop ball forming and blast drying (at a temperature of 100 °C for 5 h), it was calcined in a muffle furnace in static air at 1000 °C for 2 h to obtain spherical formed alumina;

[0129] (3) The above formed alumina was dissolved in 800 mL of water. First, an alkaline compound (ammonia water) was added to adjust the pH to 10, and then 48 g of a silicon source (tetraethyl orthosilicate) was added for a second mixing (at a temperature of 35 °C, a rotation speed of 500 rpm, and a time of 6 h) to obtain a second mixture;

[0130] (4) The above second mixture was subjected to solid-liquid separation. The obtained silicon-modified alumina precursor was dried in a blast drying oven at 100 °C for 5 h and then calcined in a tubular furnace in a nitrogen atmosphere at 800 °C for 3 h to obtain spherical silicon-modified alumina as support S4;

[0131] (5) A Pd(NH3)4(NO3)2 solution was prepared with 30 wt% ammonia water and impregnated onto the surface of the above support S4 by the incipient wetness impregnation method to obtain a catalyst precursor with a Pd loading of 2 wt%. After drying in a vacuum drying oven at 100 °C for 5 h, it was calcined in a tubular furnace in a H2 / N2 atmosphere at 500 °C for 3 h to obtain spherical catalyst Pd / S4.

[0132] Preparation Example 5

[0133] (1) 80 g of an aluminum source (γ-alumina), 4 g of an acidic compound (25 wt% dilute sulfuric acid), and 800 mL of water were subjected to a first mixing (at a temperature of 25 °C, a rotation speed of 600 rpm, and a time of 1 h) in a 1500 mL stirring kettle to obtain a first mixture;

[0134] (2) After subjecting the above first mixture to extrusion forming and blast drying (at a temperature of 100 °C for 5 h), it was calcined in a muffle furnace in static air at 800 °C for 3 h to obtain strip-shaped formed alumina;

[0135] (3) The above formed alumina was dissolved in 800 mL of water. First, an alkaline compound (ammonia water) was added to adjust the pH to 8, and then 60 g of a silicon source (tetraethyl orthosilicate) was added for a second mixing (at a temperature of 25 °C, a rotation speed of 600 rpm, and a time of 5 h) to obtain a second mixture;

[0136] (4) The above second mixture was subjected to solid-liquid separation. The obtained silicon-modified alumina precursor was dried in a blast drying oven at 100 °C for 5 h and then calcined in a tubular furnace in a nitrogen atmosphere at 600 °C for 3 h to obtain strip-shaped silicon-modified alumina as support S5;

[0137] (5) Prepare a PdCl2 solution with 36 wt% hydrochloric acid, and impregnate it onto the surface of the above support S5 by the excess impregnation method to obtain a catalyst precursor with a Pd loading of 10 wt%. After drying in a vacuum drying oven at 100 °C for 5 h, calcine it in a tubular furnace under a H2 / N2 atmosphere at 500 °C for 3 h to obtain a strip-shaped catalyst Pd / S5.

[0138] Preparation Example 6

[0139] (1) Mix 60 g of an aluminum source (hydroxyaluminum oxide), 5 g of an acidic compound (10 wt% dilute phosphoric acid), and 800 mL of water in a 1500 mL stirring kettle for the first mixing (temperature: 25 °C, rotation speed: 500 rpm, time: 1 h) to obtain a first mixture.

[0140] (2) After spray-drying and forming the above first mixture (temperature: 100 °C, time: 5 h), calcine it in a muffle furnace under static air at 900 °C for 3 h to obtain microspherical formed alumina.

[0141] (3) Dissolve the above formed alumina in 800 mL of water, first add a basic compound (ammonia water) to adjust the pH to 9, and then add 28 g of a silicon source (tetraethyl orthosilicate) for the second mixing (temperature: 25 °C, rotation speed: 500 rpm, time: 9 h) to obtain a second mixture.

[0142] (4) Separate the solid and liquid of the above second mixture. After drying the obtained silicon-modified alumina precursor in a blast drying oven at 100 °C for 5 h, calcine it in a tubular furnace under a nitrogen atmosphere at 800 °C for 6 h to obtain microspherical silicon-modified alumina as support S6.

[0143] (5) Prepare an RuCl3 solution with deionized water, and impregnate it onto the surface of the above support S6 by the deposition-precipitation method to obtain a catalyst precursor with an Ru loading of 0.5 wt%. After drying in a vacuum drying oven at 100 °C for 5 h, calcine it in a muffle furnace under static air at 500 °C for 3 h to obtain microspherical catalyst Ru / S6.

[0144] Preparation Example 7

[0145] (1) Mix 80 g of an aluminum source (γ-aluminum oxide), 50 g of an acidic compound (20 wt% dilute nitric acid), and 800 mL of water in a 1500 mL stirring kettle for the first mixing (temperature: 25 °C, rotation speed: 800 rpm, time: 1 h) to obtain a first mixture.

[0146] (2) After spray-drying and forming the above first mixture (temperature: 100 °C, time: 5 h), calcine it in a muffle furnace under static air at 1000 °C for 1 h to obtain microspherical formed alumina.

[0147] (3) Dissolve the above-mentioned formed alumina in 800 mL of water. First, add an alkaline compound (ammonium bicarbonate) to adjust the pH to 7.5, and then add 70 g of a silicon source (tetraethyl orthosilicate) for a second mixing (temperature is 40 °C, rotation speed is 800 rpm, time is 8 h) to obtain a second mixture;

[0148] (4) Perform solid-liquid separation on the above-mentioned second mixture. After the obtained silicon-modified alumina precursor is dried in a blast drying oven at 100 °C for 5 h, it is calcined in a tubular furnace under a nitrogen atmosphere at 800 °C for 6 h to obtain microspherical silicon-modified alumina as support S7;

[0149] (5) Prepare an iridium acetate solution with deionized water and impregnate it onto the surface of the above-mentioned support S7 by the deposition-precipitation method to obtain a catalyst precursor with a loading of 0.2 wt% Ir. After drying in a vacuum drying oven at 100 °C for 5 h, it is calcined in a muffle furnace under static air at 600 °C for 3 h to obtain microspherical catalyst Ir / S7.

[0150] Preparation Example 8

[0151] Mix 800 mL of deionized water, 80 g of pseudoboehmite, and 10 g of 10 wt% dilute nitric acid aqueous solution in a 1500 mL stirring kettle (temperature is 25 °C, rotation speed is 800 rpm, time is 5 h). Perform solid-liquid separation on the obtained mixture. After the obtained solid is spray-dried, it is calcined in a muffle furnace under static air at 800 °C for 3 h to obtain microspherical alumina as support S8;

[0152] Prepare a Pd(NH3)4Cl2 solution with 30 wt% ammonia water and impregnate it onto the surface of the above-mentioned support S8 by the incipient wetness impregnation method to obtain a catalyst precursor with a loading of 1 wt% Pd. After drying in a vacuum drying oven at 100 °C for 5 h, it is calcined in a muffle furnace under static air at 500 °C for 3 h to obtain microspherical catalyst Pd / S8.

[0153] Among them, the transmission infrared spectrum of the above-mentioned support S8 is shown in Figure 2(b). As can be seen from Figure 2(b), there are no signal peaks at wavenumbers 1066 cm -1 and 1160 cm -1 , indicating that there are no Si-O-Si and Si-O-Al bonds in the above-mentioned microspherical alumina.

[0154] Among them, the pyridine infrared characterization spectrum of the above-mentioned support S8 is as Figure 3 shown. As can be seen from Figure 3 , support S8 has a relatively high B acid site.

[0155] Preparation Example 9

[0156] 800 mL of deionized water, 80 g of pseudoboehmite, 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, followed by stirring at 25 °C for 12 h. The obtained mixture was spray-dried and calcined in a muffle furnace under static air at 800 °C for 3 h to obtain microspherical modified alumina as support S9;

[0157] A Pd(NH3)4Cl2 solution was prepared with 30 wt% ammonia water and impregnated onto the surface of the above support S9 by the excess impregnation method to obtain a catalyst precursor with a Pd loading of 10 wt%. After drying in a vacuum drying oven at 100 °C for 5 h, it was calcined in a muffle furnace under static air at 500 °C for 3 h to obtain microspherical catalyst Pd / S9.

[0158] Among them, the pyridine infrared characterization spectrum of the above support S9 is as Figure 3 shown, and it can be seen from Figure 3 that the support S9 has a relatively high B acid site.

[0159] Preparation Example 10

[0160] According to the method of Preparation Example 1, the difference is that the type of support is different, that is,

[0161] Steps (1)-(4) were not carried out. In step (5), the above support S1 was replaced with SAPO-34 molecular sieve, and the other types were the same, to obtain catalyst Pd / SAPO-34.

[0162] Preparation Example 11

[0163] According to the method of Preparation Example 1, the difference is that the type of support is different, that is,

[0164] Steps (1)-(4) were not carried out. In step (5), the above support S1 was replaced with TS-1 molecular sieve, and the other types were the same, to obtain catalyst Pd / TS-1.

[0165] Preparation Example 12

[0166] According to the method of Preparation Example 1, the difference is that the type of support is different, that is,

[0167] Steps (1)-(4) were not carried out. In step (5), the above support S1 was replaced with HY molecular sieve, and the other types were the same, to obtain catalyst Pd / HY.

[0168] Preparation Example 13

[0169] According to the method of Preparation Example 1, the difference is that the type of support is different, that is,

[0170] Without steps (1)-(4), in step (5), the above carrier S1 is replaced with TiO2, and the other types are the same, obtaining the catalyst Pd / TiO2.

[0171] Preparation Example 14

[0172] According to the method of Preparation Example 1, the difference is that the carrier types are different, that is,

[0173] Without steps (1)-(4), in step (5), the above carrier S1 is replaced with ZrO2, and the other types are the same, obtaining the catalyst Pd / ZrO2.

[0174] Preparation Example 15

[0175] According to the method of Preparation Example 1, the difference is that the carrier types are different, that is,

[0176] Without steps (1)-(4), in step (5), the above carrier S1 is replaced with CeO2, and the other types are the same, obtaining the catalyst Pd / CeO2.

[0177] Table 1

[0178]

[0179]

[0180] Note: * - The silicon content is calculated as SiO x where 1 ≤ x ≤ 2.

[0181] Continued Table 1

[0182]

[0183] It can be seen from the results in Table 1 that compared with Preparation Examples 8-15, the carriers in the catalysts prepared in Preparation Examples 1-7 are all silicon-modified alumina. And on the premise that the silicon-modified alumina meets a specific structure, that is, the silicon-aluminum ratio of the silicon-modified alumina < 1, the silicon in the silicon-modified alumina is connected to the surface of the alumina through Si-O-Al chemical bonds, and the adjacent silicon on the surface of the alumina is connected through Si-O-Si chemical bonds; it also simultaneously has a lower B acid density, a certain amount of L acid density, a lower attrition index, a better crushing strength, a better specific surface area, and a better average pore diameter.

[0184] Example 1

[0185] In the presence of 50 mL of methanol and 0.5 g of the catalyst Pd / S1, 0.5 g of amino-caprolactam and 1 g of benzaldehyde were reacted in a batch high-pressure reactor. The reaction conditions included: a temperature of 220 °C, a hydrogen pressure of 1 MPa, and a time of 10 h, to obtain a reaction product. The reaction product included bis(benzyl)amino-caprolactam, mono(benzyl)amino-caprolactam, and other by-products;

[0186] Among them, the results of the catalytic reaction were analyzed by gas chromatography, and the test results are listed in Table 2.

[0187] 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, the internal standard was mixed evenly with the reaction filtrate, and gas-phase analysis and quantification were carried out (Agilent GC 7890B; the separation column was: PONA column (0.32 mm × 30 m);

[0188] Among them, the mass of the converted amino-caprolactam = the mass of amino-caprolactam - the remaining mass of amino-caprolactam.

[0189]

[0190]

[0191] The yield of bis(benzyl)amino-caprolactam = the conversion rate of amino-caprolactam × the selectivity of bis(benzyl)amino-caprolactam × 100%.

[0192] Example 2 - 15

[0193] According to Example 1, the difference was that the types of catalysts were different, that is,

[0194] The catalysts in Example 1 were respectively replaced with the catalysts of Preparation Examples 2 - 15, and the obtained test results are listed in Table 2 respectively.

[0195] Table 2

[0196]

[0197] Note: 1 - refers to the conversion rate of amino-caprolactam, %; 2 - refers to the yield of bis(benzyl)amino-caprolactam, %.

[0198] From the data in Table 2, it can be seen that the preparation method of bis(benzyl)amino-caprolactam provided by the present invention has a high raw material conversion rate and product selectivity. Especially by adjusting the type of carrier and the content of active components in the catalyst, it is more conducive to improving the catalytic effect of the catalyst and obtaining bis(benzyl)amino-caprolactam with high selectivity and high yield.

[0199] Compared with Examples 8-15, Examples 1-7 adopt the technical solution that the carrier in the catalyst is silicon-modified alumina with a B acid density ≤ 2 μmol / g and an L acid density selected from 50-300 μmol / g, which is more conducive to improving the selectivity of bis(benzylamino)caprolactam, and thus a high yield of bis(benzylamino)caprolactam can be obtained.

[0200] Examples 16-23

[0201] According to Example 1, the difference is that the process parameters are different, that is,

[0202] The process parameters of Example 1 are respectively replaced with the process parameters in Table 3, and the test results obtained are listed in Table 4.

[0203] Comparative Example 1

[0204] According to Example 1, the difference is that no catalyst is added, that is,

[0205] The process parameters of Example 1 are replaced with the process parameters in Table 3, and the test results obtained are listed in Table 4.

[0206] Table 3

[0207]

[0208] Table 4

[0209]

[0210] Note: 1 - refers to the conversion rate of aminocaprolactam, %; 2 - refers to the yield of bis(benzylamino)caprolactam, %.

[0211] It can be seen from the data in Tables 3-4 that compared with Comparative Example 1 without using a catalyst, the catalyst prepared by the present invention has a higher reaction efficiency under specific reaction conditions and can obtain an ideal selectivity of bis(benzylamino)caprolactam.

[0212] 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 solution 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 synthesizing a functional caprolactam, characterized in that, The synthesis method includes: contacting and reacting aminocaprolactam and / or its derivatives with benzaldehyde in the presence of a catalyst and a solvent to obtain a functional caprolactam, which is bis(benzylamino)caprolactam; Among them, the reaction conditions include: the temperature is 150 - 350 °C; the hydrogen pressure is 0.1 - 10 MPa; the time is 5 - 15 h.

2. The synthesis method according to claim 1, wherein The reaction conditions include: the temperature is 200 - 300 °C, more preferably 220 - 280 °C; the hydrogen pressure is 1 - 5 MPa; the time is 8 - 12 h.

3. The synthesis method according to claim 1 or 2, wherein The mass ratio of the aminocaprolactam and / or its derivatives to benzaldehyde is 1:0.2 - 8, preferably 1:0.4 - 3; And / or, the aminocaprolactam and / or its derivatives are selected from aminocaprolactam and / or aminocaprolactam salts, preferably 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.

4. The synthesis 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; And / or, the catalyst includes a carrier and an active component supported on the carrier.

5. The synthesis method according to claim 4, wherein, Based on the total weight of the catalyst, the content of the active component is 0.1 - 15 wt%, preferably 0.5 - 10 wt%; And / or, the active component is selected from at least one of Pt, Pd, Rh, Ir, Ru, and Ni; And / or, the dispersion degree of the active component is ≥20%, preferably 20 - 80%.

6. The synthesis method according to claim 4 or 5, wherein The carrier is selected from at least one of molecular sieves, oxides, and modified oxides; Preferably, the molecular sieve is selected from at least one of SAPO-34 molecular sieve, TS-1 molecular sieve, and HY molecular sieve; Preferably, the oxide is selected from at least one of Al2O3, SiO2, TiO2, ZrO2, and CeO2; Preferably, the B acid density of the modified oxide is ≤2 μmol / g, and the L acid density is 50 - 300 μmol / g.

7. The synthesis method according to claim 6, wherein The modified oxide 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 silicons on the surface of the alumina are 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%; the content of the silicon in terms of SiO x is 10-50 wt%, where 1≤x≤2; Preferably, the B acid density of the silicon-modified alumina is 0 - 2 μmol / g, preferably 0 - 1.4 μmol / g, more preferably 0 - 0.5 μmol / g; the L acid density is 90 - 200 μmol / g, preferably 100 - 150 μmol / g; 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.

8. The synthesis method according to claim 7, wherein The silicon-modified alumina is prepared by the following method: (1) First mix an aluminum source, an acidic compound, and water to obtain a first mixture; (2) Subject the first mixture to shaping, first drying, and first calcination in sequence to obtain shaped alumina; (3) Dissolve the shaped alumina in water, first add an alkaline compound to adjust the pH to 7 - 12, and then add a silicon source for a second mixing to obtain a second mixture; (4) Perform solid-liquid separation on the second mixture, and the obtained silicon-modified alumina precursor is successively subjected to a second drying and a second calcination to obtain the silicon-modified alumina; And / or, the catalyst is prepared by the following method: load a soluble metal salt on the surface of the carrier, and the obtained catalyst precursor is successively subjected to a third drying and a third calcination to obtain the catalyst.

9. The synthesis method according to any one of claims 1-8, wherein, The dosage ratio of the aminocaprolactam and / or its derivative 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 selected from organic alcohols, heteroatom-containing cycloalkanes, and aromatic hydrocarbons; Preferably, the organic alcohol is selected from C1-C5 organic alcohols, preferably at least one selected from methanol, ethanol, and 1-pentanol; Preferably, the heteroatom-containing cycloalkane is selected from 1,4-dioxane and / or tetrahydrofuran; Preferably, the aromatic hydrocarbon is selected from benzene and / or toluene.

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

11. A functional nylon-6, characterized in that, The functional nylon-6 contains the functional caprolactam prepared by the synthesis method according to any one of claims 1 - 9.

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