Preparation methods and applications of methylated aminocaprolactam, cleaning / sterilization materials

Abstract

This invention relates to the field of organic synthesis technology, specifically to a method for preparing methylated aminocaprolactam and its application, as well as a cleaning / sterilizing material. In the presence of a catalyst, aminocaprolactam and / or its derivatives are contacted with methanol and subjected to a methylation reaction to obtain methylated aminocaprolactam; wherein the methylated aminocaprolactam includes methylaminocaprolactam and / or dimethylaminocaprolactam. This preparation method uses only aminocaprolactam and / or its derivatives with methanol as the reaction system, without alkylating agents, and has advantages such as controllable selectivity of the target product and a green and safe reaction process.

Description

Technical Field

[0001] This invention relates to the field of organic synthesis technology, specifically to a method for preparing methylated aminocaprolactam, an application of the methylated aminocaprolactam prepared by this method, and a cleaning / sterilizing material containing methylated aminocaprolactam. Background Technology

[0002] With economic development, people are increasingly valuing their quality of life and health, placing higher demands on the hygiene of items used in their daily lives, such as clothing, food, housing, and transportation. However, the continued spread of bacteria and viruses poses a persistent threat to human health, making the research and development and promotion of antibacterial materials of paramount importance. In recent years, polymer materials with self-cleaning / antibacterial functions have become a significant growth area in scientific research and industrialization due to their intrinsic antibacterial properties and good mechanical properties. The synthesis of antibacterial monomers is a key step in the research and promotion of these self-cleaning / antibacterial materials. Among them, aminocaprolactam and its α-amino derivatives are a class of antibacterial monomers with significant research value and development potential.

[0003] CN111116472A discloses a method for preparing aminocaprolactam-derived monomers; CN104629045A discloses a method for preparing ε-polylysine by ring-opening polymerization, including the protection / deprotection process of the α-amino group of aminocaprolactam; CN104387323A discloses a method for preparing aminocaprolactam compounds with α-amino substituents as halotoluene derivatives; CN103694174A discloses a method for preparing aminocaprolactam compounds with α-amino substituents as benzaldehyde derivatives. The above-mentioned methods for preparing derivatized aminocaprolactam monomers all have the following problems: (1) The α-amino derivatizing reagents are formaldehyde, bromides, etc. These derivatizing reagents are highly toxic and have poor chemical stability, which will cause serious environmental pollution; (2) When formaldehyde is used as an alkylating reagent, a hydrogenating reagent needs to be introduced into the reaction system. The hydrogenating reagent puts high requirements on the design and safety of the reaction device, and there are problems such as high cost, low safety, and environmental pollution.

[0004] Therefore, there is an urgent need to develop an efficient and environmentally friendly method for preparing methylated aminocaprolactam. Summary of the Invention

[0005] The purpose of this invention is to overcome the problems of existing methods for preparing methylated aminoamides, such as the use of alkylating agents like formaldehyde and halogenated derivatives, and hydrogenating agents, which lead to low selectivity of the target product, harsh process conditions, low safety, environmental pollution, and high equipment requirements. This invention provides a new method for preparing methylated aminocaprolactam and its application, as well as a cleaning / sterilizing material. This preparation method uses only aminocaprolactam and / or its derivatives with methanol as the reaction system, without alkylating agents, and has the advantages of controllable selectivity of the target product and a green and safe reaction process.

[0006] To achieve the above objectives, the first aspect of the present invention provides a method for preparing methylated aminocaprolactam, wherein aminocaprolactam and / or its derivatives are contacted with methanol in the presence of a catalyst and subjected to a methylation reaction to obtain methylated aminocaprolactam;

[0007] The methylated aminocaprolactam includes methylaminocaprolactam and / or dimethylaminocaprolactam.

[0008] Preferably, the mass ratio of aminocaprolactam and / or its derivatives to the catalyst is 1:0.1-10, more preferably 1:0.1-5, and even more preferably 1:0.5-2.

[0009] Preferably, the ratio of the amount of aminocaprolactam and / or its derivatives in g to the amount of methanol in mL is 1:5-1000, more preferably 1:20-500, and even more preferably 1:80-300.

[0010] Preferably, the catalyst is a metal-supported catalyst, more preferably a single-component supported catalyst, a two-component supported catalyst, and even more preferably a two-component supported catalyst.

[0011] Preferably, the two-component supported catalyst includes a support, and a first active component and a second active component supported on the support, wherein the first active component and the second active component exist in an alloy form.

[0012] Preferably, based on the total weight of the two-component supported catalyst, the content of the first active component is 0.1-10 wt%, preferably 0.2-5 wt%; and the content of the second active component is 0.1-20 wt%, preferably 0.5-10 wt%.

[0013] Preferably, the support is selected from oxides and / or modified oxides, wherein the oxide is selected from at least one of Al2O3, SiO2, TiO2, ZrO2 and CeO2, and the modified oxide is selected from silicon-modified alumina.

[0014] Preferably, when the carrier is selected from silicon-modified alumina, the Brønsted acid density of the silicon-modified alumina 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.

[0015] The second aspect of this invention provides the application of methylated aminocaprolactam prepared by the method provided in the first aspect as a polymer monomer in the preparation of cleaning / sterilizing materials, modified nylon materials, and long-chain branched polymer materials.

[0016] A third aspect of the present invention provides a cleaning / sterilizing material comprising methylated aminocaprolactam prepared by the preparation method provided in the first aspect.

[0017] Through the above technical solution, the present invention provides a novel method for preparing methylated aminocaprolactam. The reaction system contains only aminocaprolactam and / or its derivatives and methanol, without other alkylating agents such as aldehydes and halogenated compounds. Combined with a catalyst, this synthetic route has the characteristics of tunable selectivity of the target product, high novelty, and green safety. In particular, by controlling the support and active components in the catalyst, and limiting the physical properties of specific supports and the specific structure of active components, the selectivity of the target product is further improved. At the same time, the preparation method simplifies the process flow, is easy to operate, environmentally friendly, and convenient for industrial production.

[0018] The methylated aminocaprolactam provided by this invention can be used as a polymer monomer to prepare cleaning / sterilizing materials, modified nylon materials, long-branched polymer materials, etc. Attached Figure Description

[0019] Figure 1 This invention provides a synthetic route for methylated aminocaprolactam;

[0020] Figure 2 Here is a SEM image of the silicon-modified alumina AS-1 prepared in Example 1;

[0021] Figure 3 The pyridine infrared characterization spectra are those of silicon-modified alumina AS-1 prepared in Preparation Example 1 and shaped alumina DS-1 prepared in Preparation Example 15.

[0022] Figure 4 (a) is the transmission infrared spectrum of silicon-modified alumina AS-1 prepared in Preparation Example 1.

[0023] Figure 4 (b) is the transmission infrared spectrum of the shaped alumina DS-1 prepared in Preparation Example 15;

[0024] Figure 5The images show aberration transmission electron microscopy (TEM) image of the two-component supported catalyst PtIn / AS-1 prepared in Example 1 and elemental distribution diagrams of Pt and In.

[0025] Figure 6 This is an EDS line scan spectrum of a single PtIn nanoparticle on the surface of the two-component supported catalyst PtIn / AS-1 prepared in Example 1.

[0026] Figure 7 The images show the XRD patterns of the active components in the two-component supported catalyst PtIn / AS-1 prepared in Preparation Example 1 and the single-component supported catalyst Pt / AS-1 prepared in Preparation Example 16. Detailed Implementation

[0027] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0028] In this invention, unless otherwise specified, the terms "first," "second," "third," and "fourth" do not indicate a sequential order, nor do they limit the specific materials or steps; they are merely used to distinguish that these are not the same material or step. For example, in "first roasting," "second roasting," "third roasting," and "fourth roasting," "first," "second," "third," and "fourth" are used only to indicate that these are not the same roasting process; similarly, in "first active component" and "second active component," "first" and "second" are used only to indicate that these are not the same active component.

[0029] The first aspect of the present invention provides a method for preparing methylated aminocaprolactam, wherein aminocaprolactam and / or its derivatives are contacted with methanol in the presence of a catalyst and subjected to a methylation reaction to obtain methylated aminocaprolactam;

[0030] The methylated aminocaprolactam includes methylaminocaprolactam and / or dimethylaminocaprolactam.

[0031] The inventors of this invention have discovered that by directly contacting aminocaprolactam and / or its derivatives with methanol and carrying out a methylation reaction, methanol serves as both a reaction solvent and an alkylating agent, avoiding the use of alkylating agents such as aldehydes and halogenated compounds. This provides a novel and environmentally friendly synthetic route. Furthermore, by combining this with a catalyst, specifically limiting the catalyst to a two-component supported catalyst and limiting the two components to exist in an alloy form, and particularly by combining it with a specific support, the selectivity of the target product (methylaminocaprolactam and / or dimethylaminocaprolactam) can be controlled, further effectively improving the selectivity of the target product.

[0032] In some embodiments of the present invention, preferably, the mass ratio of aminocaprolactam 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, 1:5, 1:8, 1:10, and any value within any range of two such values, preferably 1:0.1-5, more preferably 1:0.5-2. A mass ratio satisfying the above range further improves the conversion rate of aminocaprolactam and / or its derivatives.

[0033] In some embodiments of the present invention, preferably, the aminocaprolactam and / or its derivatives are selected from aminocaprolactam and / or aminocaprolactam salts. In the present invention, aminocaprolactam salts include, but are not limited to, hydrochloride, sulfate, and nitrate salts.

[0034] In some embodiments of the present invention, more preferably, the aminocaprolactam 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.

[0035] In some embodiments of the present invention, preferably, the ratio of the aminocaprolactam and / or its derivatives in g to the methanol in mL is 1:5-1000, for example, 1:5, 1:10, 1:20, 1:30, 1:40, 1:50, 1:80, 1:100, 1:150, 1:200, 1:250, 1:300, 1:500, 1:1000, and any value within any range of any two values, preferably 1:20-500, more preferably 1:80-300.

[0036] In some embodiments of the present invention, preferably, the conditions for the methylation reaction include: a temperature of 50-180°C, a time of 0.5-24 h, and a pressure of 0.1-10 MPa; more preferably, the conditions for the methylation reaction include: a temperature of 60-120°C, a time of 1-5 h, and a pressure of 0.5-2 MPa. Using the preferred methylation reaction conditions is more conducive to improving the conversion rate of the raw materials and the selectivity of the target product. In the present invention, all pressures refer to gauge pressure. In the present invention, the atmosphere for the methylation reaction includes, but is not limited to, nitrogen, hydrogen, argon, etc.

[0037] In some embodiments of the present invention, preferably, the catalyst is a metal-supported catalyst, more preferably a single-component supported catalyst, a two-component supported catalyst, and even more preferably a two-component supported catalyst. Using preferred catalyst types is more beneficial for improving the selectivity of the target product.

[0038] In some embodiments of the present invention, preferably, the catalyst is a single-component supported catalyst, which comprises: a support and an active component supported on the support; more preferably, based on the total weight of the single-component supported catalyst, the content of the active component is 0.1-10 wt%, preferably 0.2-5 wt%; more preferably, the support is selected from at least one of Al2O3, SiO2, TiO2, ZrO2, CeO2 and silicon-modified alumina, preferably silicon-modified alumina, and the active component is selected from at least one of Pd, Pt, Ru, Ir and Rh, preferably Pd and / or Pt. Catalysts satisfying the above conditions have superior catalytic dehydrogenation performance and effectively improve the catalytic activity of single-component supported catalysts.

[0039] In some embodiments of the present invention, preferably, the catalyst is a two-component supported catalyst, which includes a support and a first active component and a second active component supported on the support, wherein the first active component and the second active component exist in an alloy form. Catalysts that meet the above conditions have superior catalytic dehydrogenation performance and more effectively improve the catalytic activity of two-component supported catalysts.

[0040] In this invention, the first active component and the second active component existing in an alloy form in the two-component supported catalyst means that the first active component and the second active component are loaded on the support in the form of a metal mixture.

[0041] In a preferred embodiment of the present invention, when the catalyst is a two-component supported catalyst and the two components exist in an alloyed state, the synthetic route for methylated aminocaprolactam is as follows: Figure 1As shown, the overall reaction pathway is as follows: In the presence of a two-component supported catalyst, aminocaprolactam and methanol undergo a methylation reaction to obtain methylated aminocaprolactam, namely, methylaminocaprolactam and / or dimethylaminocaprolactam; specifically, in the first step, methanol is dehydrogenated to formaldehyde in the presence of a two-component supported catalyst; in the second step, the formaldehyde and aminocaprolactam react to obtain a first intermediate; in the third step, the first intermediate and methanol undergo a dehydrogenation reaction to obtain methylaminocaprolactam; in the fourth step, the methylaminocaprolactam and formaldehyde undergo a methylation reaction to obtain a second intermediate; in the fifth step, the second intermediate and methanol undergo a dehydrogenation reaction to obtain dimethylaminocaprolactam. Therefore, in this invention, methanol serves as both a solvent and an alkylating agent.

[0042] In some embodiments of the present invention, preferably, based on the total weight of the two-component supported catalyst, the content of the first active component is 0.1-10 wt%, for example, 0.1 wt%, 0.2 wt%, 0.5 wt%, 1 wt%, 2 wt%, 5 wt%, 10 wt%, or any value within any range of two such values, preferably 0.2-5 wt%; the content of the second active component is 0.1-20 wt%, for example, 0.1 wt%, 0.2 wt%, 0.5 wt%, 1 wt%, 2 wt%, 5 wt%, 10 wt%, 15 wt%, 20 wt%, or any value within any range of two such values, preferably 0.5-10 wt%. Using these preferred conditions is more conducive to improving the catalytic activity and selectivity of the two-component supported catalyst.

[0043] In some embodiments of the present invention, preferably, in the binary supported catalyst, the first active component is selected from noble metal elements, more preferably from at least one of Pd, Pt, Ru, Ir, and Rh, and more preferably from Pd and / or Pt. Using these preferred conditions is more conducive to improving the catalytic activity of the binary supported catalyst, that is, improving the conversion rate of the feedstock and the selectivity of the target product, thereby improving the yield of the target product.

[0044] In some embodiments of the present invention, preferably, in the two-component supported catalyst, the second active component is selected from non-noble metal elements, preferably selected from at least one of Ni, Co, In, Sn, Ga, Zn, Mn and Fe, and more preferably selected from at least one of Ni, In, Ga and Zn.

[0045] In some embodiments of the present invention, preferably, in the two-component supported catalyst, the support is selected from oxides and / or modified oxides, wherein the oxide is selected from at least one of Al2O3, SiO2, TiO2, ZrO2 and CeO2; and the modified oxide is selected from silicon-modified alumina.

[0046] In this invention, silicon is loaded onto the surface of alumina, with the silicon bonded to the alumina surface via Si-O-Al chemical bonds, and adjacent silicon atoms bonded to the alumina surface via Si-O-Si chemical bonds. This effectively masks acidic sites on the alumina surface while ensuring the modified alumina possesses low wear index, high crushing strength, high specific surface area, and low average pore size. This allows for the control of the Brønsted acid (B acid) density on the silicon-modified alumina surface, achieving a B acid density ≤2 μmol / g. Furthermore, using the silicon-modified alumina with low B acid density as a support, combined with a first and second active component existing in an alloy form, results in a bicomponent supported catalyst exhibiting superior catalytic dehydrogenation performance while maintaining a low B acid density. This effectively enhances the catalytic activity of the bicomponent supported catalyst, leading to a high yield of the target product.

[0047] In some embodiments of the present invention, preferably, when the carrier is selected from silicon-modified alumina, the Brønsted acid density of the silicon-modified alumina is ≤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 of any two values, preferably 0-2 μmol / g, more preferably 0-1.4 μmol / g, and even more preferably 0-0.5 μmol / g.

[0048] In this invention, unless otherwise specified, the density of Brønsted acid refers to... Acid density.

[0049] In this invention, the Brønsted acid density parameter is calculated based on the amount of pyridine desorbed by heating; Brønsted acid density = amount of pyridine in silicon-modified alumina used to test the infrared spectrum of pyridine (in μmol) / mass of silicon-modified alumina (in g).

[0050] In a preferred embodiment of the present invention, the catalyst is selected from a two-component supported catalyst, including a support, and a first active component and a second active component supported on the support, wherein the support is silicon-modified alumina with a Brønsted acid density ≤ 2 μmol / g, and the first active component and the second active component exist in an alloy form.

[0051] In some embodiments of the present invention, preferably, the silicon-modified alumina comprises silicon and alumina, wherein the silicon-to-alumina ratio of the silicon-modified alumina is <1, the silicon is bonded to the surface of the alumina by Si-O-Al chemical bonds, and adjacent silicon atoms on the surface of the alumina are bonded by Si-O-Si chemical bonds. In the present invention, the bonding mode between Si, Al, and O in the silicon-modified alumina is determined by solid-state transmission infrared spectroscopy.

[0052] In this invention, unless otherwise specified, the silicon being connected to the surface of the alumina via Si-O-Al chemical bonds refers to the shared O portion of Si and Al in the alumina, thereby anchoring the silicon, which exists in the form of SiOx, to the surface of the alumina.

[0053] In some embodiments of the present invention, preferably, based on the total weight of the silicon-modified alumina, the alumina content is 50-90 wt%, more preferably 70-80 wt%; with SiO x The silicon content is calculated to be 10-50 wt%, preferably 20-30 wt%, wherein 1 ≤ x ≤ 2. Using these preferred conditions is more conducive to reducing the Brønsted acid density of the modified alumina.

[0054] In this invention, unless otherwise specified, the silicon-modified alumina contains no impurities other than silicon and alumina, that is, the sum of the contents of silicon and alumina in the silicon-modified alumina is 100 wt%.

[0055] In some embodiments of the present invention, preferably, the shape of the silicon-modified alumina is selected from spherical or strip-shaped, wherein spherical includes, but is not limited to, microspheres or small spheres.

[0056] In some embodiments of the present invention, preferably, the alumina is selected from γ-alumina. Using preferred conditions is more conducive to improving the activity of silicon-modified alumina.

[0057] In some embodiments of the present invention, preferably, the specific surface area of ​​the silicon-modified alumina is 100-220 m² / g. 2 / g, preferably 120-200m 2 / g; average pore size is 10-30nm, preferably 15-25nm; wear index is 1-20%, preferably 1-15%; crushing strength is 50-150N / cm, preferably 70-130N / cm. In this invention, unless otherwise specified, the specific surface area parameter is measured using a fully automatic isothermal adsorption instrument; the average pore size parameter is calculated using a fully automatic isothermal adsorption instrument in conjunction with the BJH model; the wear index parameter is measured using a wear index analyzer; and the crushing strength parameter is measured using a particle strength tester.

[0058] In this invention, the source of the silicon-modified alumina has a wide range of selection, as long as the silicon-modified alumina meets the above-mentioned limitations. Preferably, the silicon-modified alumina is prepared by the following method:

[0059] S1. The aluminum source, acidic compound and water are mixed in the first mixture, and the resulting first mixture is successively shaped, dried and calcined to obtain shaped alumina;

[0060] S2. Dissolve the shaped alumina in water, first add an alkaline compound to adjust the pH to 7-12, then add a silicon source for a second mixing to obtain a second mixture;

[0061] S3. The second mixture is subjected to solid-liquid separation, and the obtained modified alumina precursor is subjected to a second drying and a second calcination to obtain the silicon-modified alumina.

[0062] In some embodiments of the present invention, preferably, in step S1, the content of the aluminum source in the first mixture 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 ratio of the amount of aluminum source, acidic compound and water fed / used only needs to meet the above-mentioned limitations.

[0063] In this invention, a wide range of aluminum sources can be selected. Preferably, the aluminum source is a soluble aluminum salt, including but not limited to γ-alumina, hydroxyalumina, boehmite, aluminum chloride, aluminum nitrate, etc. When the aluminum source is selected from γ-alumina, step S1 acidifies the surface of the powdered alumina to form a hydrated hydroxyl state, which facilitates the subsequent addition of alkaline compounds and silicon sources for silicon modification.

[0064] In this invention, a wide range of types of acidic compounds can be selected. Preferably, the acidic compound is selected from at least one of hydrochloric acid, nitric acid, sulfuric acid, and phosphoric acid. In this invention, the acidic compound exists in the form of an aqueous solution, and preferably the concentration of the acidic compound in the solution is 1-50 wt%.

[0065] In this invention, the first mixing method has a wide range of options, as long as the aluminum source, acidic compound, and water are mixed. Preferably, in step S1, the conditions for the first mixing include: a temperature of 15-40°C, preferably 20-30°C; a rotation speed of 100-1000 rpm, preferably 300-1000 rpm; and a time of 0.1-5 h, preferably 0.1-2 h.

[0066] In this invention, there is a wide range of options for the molding method. In step S1, the molding method includes, but is not limited to, oil-ammonia droplet molding, spray drying molding, extrusion molding, etc.

[0067] In this invention, the first drying is intended to remove water from the first mixture. Preferably, in step S1, the conditions for the first drying include: a temperature of 80-120°C, a time of 90-110°C, and a time of 1-20 hours, preferably 1-12 hours.

[0068] In this invention, the first drying method has a wide range of options, as long as the conditions for the first drying meet the above-mentioned limitations. Preferably, the first drying method includes, but is not limited to, spray drying, forced-air drying, vacuum drying, etc.

[0069] In some embodiments of the present invention, preferably, in step S1, the conditions for the first calcination include: a temperature of 700-1200℃, preferably 800-1000℃; and a time of 1-10 hours, preferably 1-5 hours. 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.

[0070] In this invention, in step S2, the shaped alumina is first dissolved in water, an alkaline compound is added to adjust the pH, and then a silicon source is added for a second mixing, in order to obtain polyhydroxy silicic acid and / or hydroxy hydrated silicon.

[0071] In some embodiments of the present invention, preferably, in step S2, the pH is adjusted to 8-12, for example, 8, 9, 10, 10.5, 11.5, 12, and any value within the range of any two values, preferably 10.5-11.5.

[0072] In some embodiments of the present invention, preferably, in step S2, the shaped alumina, calculated as Al2O3, and the SiO2... x The weight ratio of the silicon source is 5-9:1-5, for example, 5:5, 7:3, 8:2, 9:1, and any value within the range of any two values, preferably 7-8:2-3; wherein, 1≤x≤2.

[0073] In some embodiments of the present invention, preferably, in step S2, the alkaline compound is selected from at least one of ammonium carbonate, ammonium bicarbonate and ammonia water.

[0074] In this invention, a wide range of silicon sources can be selected. Preferably, in step S2, the silicon source is a soluble silicon salt, preferably selected from organosilicon salts and / or inorganic silicon salts, including but not limited to at least one of tetramethylsilane, tetramethylsilane, silica aerogel, and silicon tetrachloride.

[0075] In this invention, unless otherwise specified, solubility means being easily soluble in water, or being easily soluble in water with the help of additives.

[0076] In some embodiments of the present invention, preferably, in step S2, the conditions for the second mixing include: a temperature of 20-70°C, preferably 25-60°C; a rotation speed of 100-1000 rpm, preferably 300-1000 rpm; and a time of 1-20 h, preferably 6-12 h.

[0077] In this invention, the solid-liquid separation method has a wide range of options, as long as the second mixture is subjected to solid-liquid separation to obtain the modified alumina precursor; the solid-liquid separation method includes, but is not limited to, filtration, sedimentation, etc.

[0078] In this invention, the second drying is intended to remove residual moisture from the modified alumina precursor. Preferably, in step S3, the conditions for the second drying include: a temperature of 80-120°C, a time of 90-110°C, and a time of 1-20 hours, preferably 1-12 hours.

[0079] In this invention, the second drying method has a wide range of options, as long as the conditions for the second drying meet the above-mentioned limitations. Preferably, the second drying method includes, but is not limited to, spray drying, forced-air drying, vacuum drying, etc.

[0080] In some embodiments of the present invention, preferably, in step S3, the conditions for the second calcination include: a temperature of 400-1000℃, preferably 500-900℃; and a time of 1-10h, preferably 1-5h. 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.

[0081] In some embodiments of the present invention, preferably, the two-component supported catalyst is prepared by the following method:

[0082] (I-1) A first soluble metal salt is loaded on the surface of the support, and the resulting first intermediate is subjected to a third drying and a third calcination to obtain a single-component supported catalyst; (I-2) A second soluble metal salt is loaded on the surface of the single-component supported catalyst, and the resulting second intermediate is subjected to a fourth drying and a fourth calcination to obtain the two-component supported catalyst.

[0083] or,

[0084] (II) The first soluble metal salt and the second soluble metal salt are loaded on the surface of the support, and the resulting third intermediate is subjected to a fifth drying and a fifth calcination in sequence to obtain the two-component supported catalyst.

[0085] The third, fourth, and fifth calcinations are each carried out independently in a hydrogen-containing atmosphere.

[0086] In this invention, unless otherwise specified, there are two methods for preparing the two-component supported catalyst: (I) First, a first soluble metal salt is loaded onto the surface of a support, and after a third drying and a third calcination, a second soluble metal salt is loaded onto the surface of the obtained single-component supported catalyst, and after a fourth drying and a fourth calcination, a two-component supported catalyst is obtained; (II) The first soluble metal salt and the second soluble metal salt are directly loaded onto the surface of a support, and directly after a fifth drying and a fifth calcination, a two-component supported catalyst is obtained, wherein the third, fourth, and fifth calcinations are all carried out in a hydrogen-containing atmosphere.

[0087] In some embodiments of the present invention, preferably, the hydrogen content in the hydrogen-containing atmosphere is ≥10% by volume, for example, 60%, 70%, 80%, 90%, 100%, and any value within the range of any two of these values, preferably 20-90% by volume. When the hydrogen content in the hydrogen-containing atmosphere is less than 10%, the alloy morphology of the two-component catalyst is not ideal.

[0088] In some embodiments of the present invention, preferably, the hydrogen-containing atmosphere further contains an inert gas, wherein the inert gas includes, but is not limited to, nitrogen, helium, etc., and is preferably nitrogen; more preferably, the volume ratio of hydrogen to inert gas in the hydrogen-containing atmosphere is 1-9:9-1, for example, 1:9, 2:8, 3:7, 4:6, 6:4, 7:3, 8:2, 9:1, and any value within the range of any two values, preferably 2-9:8-1.

[0089] In a preferred embodiment of the present invention, preferably, the hydrogen-containing atmosphere comprises hydrogen and nitrogen, and the volume ratio of hydrogen to nitrogen is 2-9:8-1.

[0090] In a preferred embodiment of the present invention, preferably, the loading of the first soluble metal salt, calculated as metal element, is 0.1-10 wt%, more preferably 0.2-5 wt%. In the present invention, unless otherwise specified, the loading parameters are based on the total weight of the two-component supported catalyst.

[0091] In a preferred embodiment of the present invention, preferably, the loading of the second soluble metal salt, calculated as a metal element, is 0.1-20 wt%, more preferably 0.5-10 wt%.

[0092] In this invention, steps (I-1), (I-2), and (II) offer a wide range of options for the loading methods of the first soluble metal salt, the second soluble metal salt, and the first and second soluble metal salts, as long as the loading amount of the soluble metal salt meets the above-mentioned limitations. Preferably, the loading method is selected from impregnation and deposition / precipitation methods.

[0093] In this invention, in steps (I-1), (I-2), and (II), when the loading method is impregnation, an impregnation solution containing a soluble metal salt needs to be prepared. Depending on the amount of impregnation solution used, the impregnation method is selected from excess impregnation and saturated impregnation. Depending on the method of impregnation, the impregnation method is selected from immersion impregnation and spray impregnation. By adjusting and controlling the concentration and amount of the impregnation solution or the amount of the carrier, a catalyst with a specific loading can be obtained, which is easily understood by those skilled in the art.

[0094] In some embodiments of the present invention, in steps (I-1), (I-2), and (II), when the loading method is impregnation, the solvent in the impregnation solution containing the soluble metal salt includes, but is not limited to, water, ammonia, 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.

[0095] In some embodiments of the present invention, in steps (I-1), (I-2), and (II), when the loading method is a 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.

[0096] In some embodiments of the present invention, preferably, the first soluble metal salt is selected from hydrochloride, sulfate, nitrate, and acetate containing at least one of Pt, Pd, Rh, Ir, and Ru, and more preferably from hydrochloride, sulfate, nitrate, and acetate containing Pd and / or Pt. In the present invention, the first soluble metal salt includes, but is not limited to, PdCl2, H2PtCl6, Pd(NO3)2, RuCl3, and iridium acetate.

[0097] In some embodiments of the present invention, preferably, the second soluble metal salt is selected from hydrochloride, sulfate, nitrate, and acetate containing at least one of Ni, Co, In, Sn, Ga, Zn, Mn, and Fe, and more preferably from hydrochloride, sulfate, nitrate, and acetate containing at least one of Ni, In, Ga, and Zn. In the present invention, the soluble metal salt includes, but is not limited to, In(NO3)2, Ga(NO3)2, NiCl2, Mn(NO3)2, and FeCl3.

[0098] In this invention, in step (I-1), the first intermediate includes a support and a first soluble metal salt supported on the support; the third drying is intended to remove the solvent remaining in the first intermediate; the third calcination is intended to reduce the first soluble metal salt to a first elemental metal in a hydrogen-containing atmosphere to obtain a single-component supported catalyst (including a support and a first active component supported on the surface of the support).

[0099] In this invention, in step (I-2), the second intermediate comprises a single-component supported catalyst and a second soluble metal salt supported on the single-component supported catalyst; the fourth drying is intended to remove residual solvent from the second intermediate; the fourth calcination is intended to reduce the second soluble metal salt to a second elemental metal in a hydrogen-containing atmosphere, and to form an alloy between the first and second elemental metals, thereby obtaining a two-component supported catalyst (comprising a support and a first and a second active component supported on the surface of the support).

[0100] In this invention, in step (II), the third intermediate includes a support and a first soluble metal salt supported on the support; the fifth drying is intended to remove the solvent remaining in the third intermediate; the fifth calcination is intended to reduce the first soluble metal salt and the second soluble metal salt to a first metallic element and a second metallic element, respectively, in a hydrogen-containing atmosphere, and exist in an alloy form to obtain a two-component supported catalyst (including a support and a first active component and a second active component supported on the surface of the support).

[0101] In some embodiments of the present invention, preferably, the conditions for the third, fourth, and fifth drying processes each independently include: a temperature of 80-120°C, a time of 90-110°C, and a time of 1-20 hours, preferably 1-12 hours. In the present invention, the methods of the third, fourth, and fifth drying processes include, but are not limited to, spray drying, forced-air drying, vacuum drying, etc.

[0102] In some embodiments of the present invention, preferably, the conditions for the third, fourth, and fifth calcinations each independently include: a temperature of 400-800°C, a time of 450-750°C, and a time of 1-10 hours, preferably 1-5 hours. In the present invention, the third, fourth, and fifth calcinations are carried out in a muffle furnace or a tubular furnace, and the calcination atmosphere is a hydrogen-containing atmosphere.

[0103] In some embodiments of the present invention, preferably, the morphology of the two-component supported catalyst is selected from spherical or strip-shaped, wherein spherical includes, but is not limited to, microspheres or small spheres.

[0104] In this invention, unless otherwise specified, the macroscopic morphology of the catalyst is measured using a scanning electron microscope; the morphology of the two-component alloy supported on the catalyst surface is measured using an X-ray diffractometer and an elemental energy dispersive spectroscopy (EDS) accessory of a spherical aberration transmission electron microscope.

[0105] The second aspect of this invention provides the application of methylated aminocaprolactam prepared by the method provided in the first aspect as a polymer monomer in the preparation of cleaning / sterilizing materials, modified nylon materials, and long-chain branched polymer materials.

[0106] A third aspect of the present invention provides a cleaning / sterilizing material, the cleaning / sterilizing material comprising: methylated aminocaprolactam prepared by the preparation method provided in the first aspect.

[0107] According to a particularly preferred embodiment of the present invention, a method for preparing methylated aminocaprolactam involves contacting aminocaprolactam and / or its derivatives with methanol and carrying out a methylation reaction in the presence of a two-component supported catalyst to obtain methylated aminocaprolactam.

[0108] The methylated aminocaprolactam includes methylaminocaprolactam and / or dimethylaminocaprolactam;

[0109] The dual-component supported catalyst includes a support, and a first active component and a second active component supported on the support, wherein the first active component and the second active component exist in an alloy form; the support is selected from silicon-modified alumina with a Brønsted acid density of 0-0.5 μmol / g; the first active component is selected from Pd and / or Pt; and the second active component is selected from at least one of Ni, In, Ga, and Zn.

[0110] The silicon-modified alumina comprises silicon and alumina, wherein the silicon-to-alumina ratio is <1, the silicon is bonded to the surface of the alumina via Si-O-Al chemical bonds, and adjacent silicon atoms on the surface of the alumina are bonded via Si-O-Si chemical bonds; based on the total weight of the silicon-modified alumina, the alumina content is 70-80 wt%; and the content of SiO2 is...x The silicon content is 20-30 wt%, wherein 1 ≤ x ≤ 2; the specific surface area of ​​the silicon-modified alumina is 120-200 m² / g. 2 / g; average pore size is 15-25nm; abrasion index is 1-15%; crushing strength is 70-130N / cm;

[0111] The conditions for the methylation reaction include: a temperature of 60-120℃, a time of 1-5h, and a pressure of 0.5-2MPa.

[0112] The present invention will be described in detail below through embodiments.

[0113] The Brønsted acid density parameter is calculated based on the amount of pyridine desorbed upon heating; that is, Brønsted acid density = amount of pyridine in silicon-modified alumina used to test the infrared spectrum of pyridine (in μmol) / mass of silicon-modified alumina (in g).

[0114] The bonding mode between Si, Al, and O in silicon-modified alumina was determined by solid-state transmission infrared spectroscopy.

[0115] Specific surface area parameters were measured using a fully automated isothermal adsorption analyzer.

[0116] The average pore size parameters were obtained using a fully automated isothermal adsorption instrument and in conjunction with the BJH model.

[0117] The wear index parameters were measured using a wear index analyzer.

[0118] Crushing strength parameters were measured using a particle strength tester;

[0119] The macroscopic morphology of the silicon-modified alumina / two-component supported catalyst was measured by scanning electron microscopy.

[0120] The alloy morphology of the two components in the two-component supported catalyst was determined using an X-ray diffractometer and an elemental energy dispersive spectroscopy (EDS) accessory of a spherical aberration transmission electron microscope.

[0121] Preparation Examples 1-18 were used to prepare catalysts. The physical properties of the supports are listed in Table 1, and the physical properties of the catalysts are listed in Table 2.

[0122] Preparation Example 1

[0123] (1) 80g of aluminum source (boehmite), 5g of acidic compound (30wt% dilute nitric acid) and 800mL of water were mixed in a 1500mL stirred tank for the first time (temperature 25℃, speed 600rpm, time 1h) to obtain the first mixture;

[0124] The first mixture was spray-dried (at 100°C for 5 hours) and then calcined in a muffle furnace at 800°C under static air for 3 hours to obtain microspherical alumina.

[0125] (2) Dissolve the above-mentioned shaped alumina in 800 mL of water, first add an alkaline compound (ammonia) to adjust the pH to 10, then add 60 g of silicon source (tetraethyl orthosilicate) for a second mixing (temperature 25℃, rotation speed 600 rpm, time 12 h) to obtain the second mixture;

[0126] (3) The above second mixture was subjected to solid-liquid separation. The modified alumina precursor was dried in a vacuum drying oven at 100°C for 5 hours and then calcined in a muffle furnace at 600°C for 3 hours in a static air atmosphere to obtain microspherical silicon modified alumina AS-1.

[0127] The SEM image of the silicon-modified alumina AS-1 is shown below. Figure 2 As shown, by Figure 2 It can be seen that silicon-modified alumina AS-1 has a microsphere morphology;

[0128] The pyridine infrared characterization spectrum of the aforementioned silicon-modified alumina AS-1 is shown below. Figure 3 As shown, by Figure 3 It can be seen that silicon-modified alumina AS-1 has an extremely low number of Brønsted acid sites, and the Brønsted acid density is 0 μmol / g;

[0129] The transmission infrared spectrum of the aforementioned silicon-modified alumina AS-1 is as follows: Figure 4 As shown in (a), by Figure 4 (a) It can be seen that the wave number is 1066 cm⁻¹ -1 and 1160cm -1 The signal peaks at these locations are vibrational absorption peaks of Si-O-Si and Si-O-Al bonds, respectively, indicating that silicon in silicon-modified alumina AS-1 is bonded to alumina through chemical bonds, and that adjacent silicon on the surface of alumina is bonded to SiO2. x Clusters of (1≤x≤2) exist.

[0130] (4) H2PtCl6 solution was impregnated onto the surface of the above silicon-modified alumina AS-1 by excess impregnation method to obtain a first intermediate with a Pt loading of 5wt%. After drying in a vacuum drying oven at 100℃ for 5h, it was calcined in a muffle furnace at 500℃ for 3h in a static H2 atmosphere to obtain a single-component supported catalyst.

[0131] In(NO3)3 solution was impregnated onto the surface of the above single-component supported catalyst using a saturated impregnation method to obtain a second intermediate with an In loading of 2wt%. After drying in a forced-air drying oven at 80℃ for 12h, it was calcined in a tube furnace at 600℃ for 4h in a H2 atmosphere to obtain a microspherical two-component supported catalyst PtIn / AS-1, wherein Pt and In exist in an alloy state.

[0132] The aberration-corrected transmission electron microscopy (TEM) image, elemental distribution maps of Pt and In, EDS line scan spectra, and XRD patterns of individual PtIn nanoparticles on the surface of the aforementioned two-component supported catalyst PtIn / AS-1 are shown below. Figure 5-7 As shown, by Figure 5-7 It can be seen that in the above-mentioned two-component supported catalyst PtIn / AS-1, Pt and In are supported on the surface of silicon-modified alumina AS-1, and Pt and In exist in alloy form.

[0133] Preparation Example 2

[0134] (1) 50g of aluminum source (boehmite), 10g of acidic compound (5wt% dilute nitric acid) and 800mL of water were mixed in a 1500mL stirred tank (temperature 20℃, speed 500rpm, time 1h) to obtain the first mixture;

[0135] The first mixture was spray-dried (at 100°C for 5 hours) and then calcined in a muffle furnace at 1000°C for 1 hour under static air to obtain microspherical alumina.

[0136] (2) Dissolve the above-mentioned shaped alumina in 800 mL of water, first add an alkaline compound (ammonium bicarbonate) to adjust the pH to 9, then add 50 g of silicon source (silica aerogel) for a second mixing (temperature 25℃, rotation speed 500 rpm, time 8 h) to obtain the second mixture;

[0137] (3) The above second mixture was subjected to solid-liquid separation. The modified alumina precursor was dried in a vacuum drying oven at 100°C for 5 hours and then calcined in a tube furnace at 800°C for 2 hours in a nitrogen atmosphere to obtain microspherical silicon modified alumina AS-2.

[0138] (4) Pd(NH3)4(NO3)2 solution was impregnated onto the surface of the above silicon-modified alumina AS-2 by excess impregnation method to obtain a first intermediate with a Pd loading of 6wt%. After drying in a vacuum drying oven at 100℃ for 5h, it was calcined in a muffle furnace at 500℃ for 3h under static H2 atmosphere to obtain a single-component supported catalyst.

[0139] A Zn(NO3)2 solution was impregnated onto the surface of the above-mentioned single-component supported catalyst using a saturation impregnation method to obtain a second intermediate with a Zn loading of 10 wt%. After drying in a forced-air drying oven at 80 °C for 12 h, the intermediate was calcined in a tube furnace at 600 °C for 4 h in a mixed atmosphere of H2 and N2 (H2 to N2 volume ratio 2:8) to obtain a microspherical two-component supported catalyst PdZn / AS-2, in which Pd and Zn exist in an alloyed state.

[0140] Preparation Example 3

[0141] (1) 20g of aluminum source (aluminum hydroxide), 1g of acidic compound (30wt% dilute hydrochloric acid) and 800mL of water were mixed in a 1500mL stirred tank (temperature 30℃, speed 500rpm, time 1h) to obtain the first mixture;

[0142] The first mixture was extruded, dried by forced air (at 100°C for 5 hours), and then calcined in a muffle furnace at 800°C for 3 hours under static air to obtain strip-shaped alumina.

[0143] (2) Dissolve the above-mentioned shaped alumina in 800 mL of water, first add an alkaline compound (ammonia) to adjust the pH to 10, then add 56 g of silicon source (silicon tetrachloride) for a second mixing (temperature 50℃, rotation speed 500 rpm, time 10 h) to obtain the second mixture;

[0144] (3) The second mixture was subjected to solid-liquid separation. The modified alumina precursor was dried in a vacuum drying oven at 100°C for 5 hours and then calcined in a tube furnace at 600°C for 6 hours in a nitrogen atmosphere to obtain strip-shaped silicon modified alumina AS-3.

[0145] (4) H2PtCl6 solution was impregnated onto the surface of the above silicon-modified alumina AS-3 by saturation impregnation method to obtain a first intermediate with a Pt loading of 2wt%. After drying in a vacuum drying oven at 100℃ for 5h, it was calcined in a tube furnace at 500℃ for 3h in a mixed atmosphere of H2 and N2 (H2 and N2 volume ratio 4:6) to obtain a single-component supported catalyst.

[0146] Ni(NO3)3 solution was impregnated onto the surface of the above-mentioned single-component supported catalyst using a saturation impregnation method to obtain a second intermediate with a Ni loading of 0.1 wt%. After drying in a forced-air drying oven at 120 °C for 6 h, it was calcined in a tube furnace at 750 °C for 4 h in a mixed atmosphere of H2 and N2 (H2 to N2 volume ratio 4:6) to obtain a strip-shaped two-component supported catalyst PtNi / AS-3, wherein Pt and Ni exist in an alloy state.

[0147] Preparation Example 4

[0148] (1) 50g of aluminum source (boehmite), 2g of acidic compound (50wt% dilute phosphoric acid) and 800mL of water were mixed in a 1500mL stirred tank (temperature 25℃, speed 800rpm, time 1h) to obtain the first mixture;

[0149] The first mixture was formed by drop balling, dried by forced air (at 100°C for 5 hours), and then calcined in a muffle furnace at 800°C for 2 hours under static air to obtain small spherical alumina.

[0150] (2) Dissolve the above-mentioned shaped alumina in 800 mL of water, first add an alkaline compound (ammonia) to adjust the pH to 10, then add 48 g of silicon source (tetraethyl orthosilicate) for a second mixing (temperature 35℃, rotation speed 500 rpm, time 6 h) to obtain the second mixture;

[0151] (3) The second mixture was subjected to solid-liquid separation. The modified alumina precursor was dried in a vacuum drying oven at 100°C for 5 hours and then calcined in a muffle furnace at 800°C for 3 hours in a static nitrogen atmosphere to obtain small spherical silicon modified alumina AS-4.

[0152] (4) Pd(NH3)4(NO3)2 solution was impregnated onto the surface of the above silicon-modified alumina AS-4 by excess impregnation method to obtain a first intermediate with a Pd loading of 2wt%. After drying in a vacuum drying oven at 100℃ for 5h, it was calcined in a tube furnace at 500℃ for 3h in a mixed atmosphere of H2 and N2 (H2 and N2 volume ratio of 1:9) to obtain a single-component supported catalyst.

[0153] In(NO3)3 solution was impregnated onto the surface of the above-mentioned single-component supported catalyst by deposition precipitation method to obtain a second intermediate with an In loading of 1 wt%. After drying in a forced-air drying oven at 100°C for 8 h, it was calcined in a tube furnace at 600°C for 4 h in a mixed atmosphere of H2 and N2 (H2 to N2 volume ratio of 4:6) to obtain a small spherical two-component supported catalyst PdIn / AS-4, wherein Pd and In exist in an alloy state.

[0154] Preparation Example 5

[0155] The method is the same as in Preparation Example 1, except that in step (4),

[0156] Pd(NH3)4Cl2 solution was impregnated onto the surface of the above-mentioned silicon-modified alumina AS-1 by excess impregnation method to obtain a first intermediate with a Pd loading of 6wt%. After drying in a vacuum drying oven at 100℃ for 5h, it was calcined in a muffle furnace at 500℃ for 3h in a static H2 atmosphere to obtain a single-component supported catalyst.

[0157] In(NO3)3 solution was impregnated onto the surface of the above single-component supported catalyst using a saturated impregnation method to obtain a second intermediate with an In loading of 2wt%. After drying in a forced-air drying oven at 80℃ for 12h, it was calcined in a tube furnace at 600℃ for 4h in a H2 atmosphere to obtain a microspherical two-component supported catalyst PdIn / AS-1, wherein Pd and In exist in an alloy state.

[0158] Preparation Example 6

[0159] The method is the same as in Preparation Example 1, except that in step (4),

[0160] H2PtCl6 solution was impregnated onto the surface of the above-mentioned silicon-modified alumina AS-1 by excess impregnation method to obtain a first intermediate with a Pt loading of 10wt%. After drying in a vacuum drying oven at 80℃ for 12h, it was calcined in a muffle furnace at 600℃ for 3h in a static H2 atmosphere to obtain a single-component supported catalyst.

[0161] Ga(NO3)3 solution was impregnated onto the surface of the above-mentioned single-component supported catalyst using a saturated impregnation method to obtain a second intermediate with a Ga loading of 3wt%. After drying in a forced-air drying oven at 120℃ for 3h, it was calcined in a tube furnace at 600℃ for 4h in a H2 atmosphere to obtain a microspherical two-component supported catalyst PtGa / AS-1, wherein Pt and Ga exist in an alloy state.

[0162] Preparation Example 7

[0163] The method is the same as in Preparation Example 1, except that in step (4),

[0164] H2PtCl6 solution was impregnated onto the surface of the above-mentioned silicon-modified alumina AS-1 by excess impregnation method to obtain a first intermediate with a Pt loading of 5wt%. After drying in a vacuum drying oven at 80℃ for 12h, it was calcined in a muffle furnace at 600℃ for 3h in a static H2 atmosphere to obtain a single-component supported catalyst.

[0165] Zinc acetate solution was impregnated onto the surface of the above-mentioned single-component supported catalyst using a saturated impregnation method to obtain a second intermediate with a Zn loading of 10 wt%. After drying in a forced-air drying oven at 120 °C for 3 h, it was calcined in a tube furnace at 600 °C for 4 h in a H2 atmosphere to obtain a microspherical two-component supported catalyst PtZn / AS-1, wherein Pt and Zn exist in an alloy state.

[0166] Preparation Example 8

[0167] The method is the same as in Preparation Example 1, except that in step (4),

[0168] A mixed solution of H2PtCl6 and In(NO3)3 was prepared using deionized water and impregnated into the modified silica alumina AS-1 using an excess impregnation method to obtain a third intermediate with a Pt loading of 5 wt% and an In loading of 2 wt%. After drying in a forced-air drying oven at 80°C for 12 h, it was calcined in a tube furnace at 600°C for 4 h in an H2 atmosphere to obtain a microspherical two-component supported catalyst PtIn-co / AS-1, in which Pt and In exist in an alloyed state.

[0169] Preparation Example 9

[0170] H2PtCl6 solution was impregnated onto the surface of Al2O3 by deposition precipitation to obtain a first intermediate with a Pt loading of 2wt%. After drying in a vacuum drying oven at 100℃ for 6h, it was calcined in a muffle furnace at 500℃ for 3h in a static H2 atmosphere to obtain a single-component supported catalyst.

[0171] SnCl2 solution was impregnated onto the surface of the above-mentioned single-component supported catalyst by deposition precipitation method to obtain a second intermediate with Sn loading of 1wt%. After drying in a forced-air drying oven at 120℃ for 3h, it was calcined in a tube furnace at 600℃ for 4h in H2 atmosphere to obtain a two-component supported catalyst PtSn / Al2O3, wherein Pt and Sn exist in alloy state.

[0172] Preparation Example 10

[0173] Pd(NH3)4(NO3)2 solution was impregnated onto the surface of ZrO2 by the isovolute impregnation method to obtain a first intermediate with a Pd loading of 6wt%. After drying in a vacuum drying oven at 120℃ for 3h, it was calcined in a muffle furnace at 400℃ for 3h in a static H2 atmosphere to obtain a single-component supported catalyst.

[0174] A Mn(NO3)2 solution was prepared using deionized water and impregnated onto the surface of the above-mentioned single-component supported catalyst using a saturated impregnation method to obtain a second intermediate with a Mn loading of 20 wt%. After drying in a forced-air drying oven at 100 °C for 8 h, it was calcined in a tube furnace at 600 °C for 4 h in an H2 atmosphere to obtain a two-component supported catalyst PdMn / ZrO2, wherein Pd and Mn exist in an alloyed state.

[0175] Preparation Example 11

[0176] Iridium acetate solution was impregnated onto the surface of Al2O3 by the constant volume impregnation method to obtain a first intermediate with an Ir loading of 2wt%. After drying in a vacuum drying oven at 100℃ for 6h, it was calcined in a muffle furnace at 500℃ for 3h in a static H2 atmosphere to obtain a single-component supported catalyst.

[0177] The CoCl3 solution was impregnated onto the surface of the above single-component supported catalyst using a saturated impregnation method to obtain a second intermediate with a Co loading of 0.1 wt%. After drying in a forced-air drying oven at 120 °C for 3 h, it was calcined in a tube furnace at 800 °C for 6 h in a H2 atmosphere to obtain a two-component supported catalyst IrCo / Al2O3, wherein Ir and Co exist in an alloyed form.

[0178] Preparation Example 12

[0179] RhCl3 solution was impregnated onto the surface of SiO2 using an equal volume impregnation method to obtain a first intermediate with a Rh loading of 6 wt%. After drying in a vacuum drying oven at 100 °C for 6 h, it was calcined in a muffle furnace at 400 °C for 9 h in a static H2 atmosphere to obtain a single-component supported catalyst.

[0180] NiCl2 solution was impregnated onto the surface of the above single-component supported catalyst using a saturated impregnation method to obtain a second intermediate with a Ni loading of 2wt%. After drying in a forced-air drying oven at 120℃ for 3h, it was calcined in a tube furnace at 800℃ for 6h in a H2 atmosphere to obtain a two-component supported catalyst RhNi / SiO2, wherein Rh and Ni exist in an alloy state.

[0181] Preparation Example 13

[0182] H2PtCl6 solution was impregnated onto the surface of ZrO2 by an equal volume impregnation method to obtain a first intermediate with a Pt loading of 8 wt%. After drying in a vacuum drying oven at 100 °C for 6 h, it was calcined in a muffle furnace at 400 °C for 3 h in a static H2 atmosphere to obtain a single-component supported catalyst.

[0183] FeCl3 solution was impregnated onto the surface of the above single-component supported catalyst using a saturated impregnation method to obtain a second intermediate with a Fe loading of 3 wt%. After drying in a forced-air drying oven at 120 °C for 3 h, it was calcined in a tube furnace at 600 °C for 4 h in a H2 atmosphere to obtain a two-component supported catalyst PtFe / ZrO2, wherein Pt and Fe exist in an alloyed state.

[0184] Preparation Example 14

[0185] Pd(NH3)4(NO3)2 solution was impregnated onto the surface of CeO2 by the isovolute impregnation method to obtain a first intermediate with a Pd loading of 6wt%. After drying in a vacuum drying oven at 100℃ for 6h, it was calcined in a muffle furnace at 400℃ for 3h in a static H2 atmosphere to obtain a single-component supported catalyst.

[0186] Zinc acetate solution was impregnated onto the surface of the above-mentioned single-component supported catalyst using an excess impregnation method to obtain a second intermediate with a Zn loading of 2 wt%. After drying in a forced-air drying oven at 120 °C for 3 h, it was calcined in a tube furnace at 600 °C for 4 h in a H2 atmosphere to obtain a two-component supported catalyst PdZn / CeO2, wherein Pd and Zn exist in an alloyed state.

[0187] Preparation Example 15

[0188] (1) 80g of aluminum source (boehmite), 10g of acidic compound (10wt% dilute nitric acid) and 800mL of water were mixed in a 1500mL stirred tank (temperature 25℃, speed 600rpm, time 1h) to obtain the first mixture;

[0189] The first mixture was spray-dried (at 100°C for 5 hours) and then calcined in a muffle furnace at 800°C under static air for 3 hours to obtain microspherical alumina DS-1.

[0190] The pyridine infrared characterization spectrum of the above-mentioned shaped alumina DS-1 is as follows: Figure 3 As shown, by Figure 3 It can be seen that the shaped alumina DS-1 has an extremely high number of Brønsted acid sites, and the Brønsted acid density is 1.5 μmol / g;

[0191] The transmission infrared spectrum of the above-mentioned shaped alumina DS-1 is as follows: Figure 4 As shown in (b), from 4(b), the wavenumber is 1066 cm⁻¹. -1 and 1160cm -1 The absence of signal peaks indicates that Si-O-Si and Si-O-Al bonds are absent in the shaped alumina DS-1.

[0192] (2) H2PtCl6 solution was impregnated onto the surface of the above-formed alumina DS-1 by excess impregnation method to obtain a first intermediate with a Pt loading of 5wt%. After drying in a vacuum drying oven at 100℃ for 5h, it was calcined in a muffle furnace at 500℃ for 3h in a static H2 atmosphere to obtain a single-component supported catalyst.

[0193] In(NO3)3 solution was impregnated onto the surface of the above single-component supported catalyst using a saturated impregnation method to obtain a second intermediate with an In loading of 2wt%. After drying in a forced-air drying oven at 80℃ for 12h, it was calcined in a tube furnace at 600℃ for 4h in a H2 atmosphere to obtain a microspherical two-component supported catalyst PtIn / DS-1, wherein Pt and In exist in an alloy state.

[0194] Preparation Example 16

[0195] The method is the same as in Preparation Example 1, except that in step (4),

[0196] H2PtCl6 solution was impregnated onto the surface of the silicon-modified alumina AS-1 using an excess impregnation method to obtain a first intermediate with a Pt loading of 5wt%. After drying in a vacuum drying oven at 100℃ for 5h, it was calcined in a muffle furnace at 500℃ for 3h in a static H2 atmosphere to obtain a microspherical single-component supported catalyst Pt / AS-1.

[0197] The XRD pattern of the active component Pt in the above-mentioned single-component supported catalyst Pt / AS-1 is shown below. Figure 7 As shown, by Figure 7 It can be seen that the single-component supported catalyst Pt / AS-1 has a crystal phase peak of Pt nanoparticles, but no alloy crystal phase peak of Pt and other non-noble metal components.

[0198] Preparation Example 17

[0199] The method is the same as in Preparation Example 1, except that in step (4),

[0200] H2PtCl6 solution was impregnated onto the surface of the above-mentioned silicon-modified alumina AS-1 by excess impregnation method to obtain a first intermediate with a Pt loading of 5wt%. After drying in a vacuum drying oven at 100℃ for 5h, it was calcined in a muffle furnace at 500℃ for 3h in a static H2 atmosphere to obtain a single-component supported catalyst.

[0201] In(NO3)3 solution was impregnated onto the surface of the above single-component supported catalyst using a saturated impregnation method to obtain a second intermediate with an In loading of 2wt%. After drying in a forced-air drying oven at 80℃ for 12h, it was calcined in a tube furnace at 600℃ for 4h in an air atmosphere to obtain a microspherical two-component supported catalyst PtIn / AS-1”, in which Pt and In exist in the form of oxides.

[0202] Preparation Example 18

[0203] H2PtCl6 solution was impregnated onto the surface of TiO2 using an excess impregnation method to obtain a first intermediate with a Pt loading of 5wt%. After drying in a vacuum drying oven at 100℃ for 5h, it was calcined in a muffle furnace at 500℃ for 3h in a static H2 atmosphere to obtain a single-component supported catalyst Pt / TiO2.

[0204] Table 1

[0205]

[0206] Note 1 - Silicon content is expressed as SiO₂ x Calculate, where 1≤x≤2.

[0207] Continued from Table 1

[0208]

[0209] As shown in Table 1, compared with Preparation Examples 9-15 and 18, Preparation Examples 1-8 and 16-17 all used silicon-modified alumina with a specific structure as a carrier. Among them, 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. Adjacent silicon on the surface of alumina is connected through Si-O-Si chemical bonds. It also has lower Brønsted acid density, lower wear index, better crushing strength, better specific surface area and better average pore size.

[0210] Table 2

[0211]

[0212]

[0213] Note: In the 2-two-component supported catalyst, the first active component and the second active component exist in an alloy form.

[0214] As can be seen from the data in Table 2, compared with Preparation Examples 16-18, the first active component and the second active component in the two-component supported catalysts prepared by the method provided in Preparation Examples 1-15 exist in an alloy form, thereby improving the catalytic activity of the two-component supported catalysts.

[0215] Example 1

[0216] 0.2 g of aminocaprolactam was methylated in a batch high-pressure reactor in the presence of 50 mL of methanol and 0.4 g of a two-component supported catalyst PtIn / AS-1. The methylation reaction conditions were: temperature 80 °C, N2 pressure 0.7 MPa, and time 4 h. The reaction products included methylaminocaprolactam, dimethylaminocaprolactam, and other byproducts.

[0217] The conditions and process parameters for the methylation reaction are listed in Table 3. The results of the catalytic reaction were analyzed by gas chromatography, and the test results are listed in Table 4.

[0218] Specifically, the product detection involves filtering and separating the reaction solution and catalyst, adding a certain amount of n-decane as an internal standard, mixing the internal standard with the reaction filtrate, and performing gas phase analysis and quantification (Angilent GC7890B; separation column: PONA column (0.32mm×30m)).

[0219] The conversion rate of aminocaprolactam is calculated as follows: (mass of converted aminocaprolactam / mass of aminocaprolactam fed) × 100%; where the mass of converted aminocaprolactam is calculated as: (mass of aminocaprolactam) – (mass of remaining aminocaprolactam).

[0220] Selectivity of methylaminocaprolactam = (mass of methylaminocaprolactam ÷ 142) / (mass of converted aminocaprolactam ÷ 128) × 100%.

[0221] Dimethylaminocaprolactam selectivity = (mass of dimethylaminocaprolactam ÷ 156) / (mass of converted aminocaprolactam ÷ 128) × 100%;

[0222] The selectivity of methylated aminocaprolactam = the selectivity of methylaminocaprolactam + the selectivity of dimethylaminocaprolactam.

[0223] Example 2-18

[0224] The method is the same as in Example 1, except that...

[0225] The catalysts were replaced with those prepared in Examples 2-18. The conditions and process parameters for the methylation reaction are listed in Table 3. The catalytic reaction results were analyzed by gas chromatography, and the test results are listed in Table 4.

[0226] Comparative Example 1

[0227] According to Chen, J.; Dong, Y.; Xiao, C.; Tao, Y.; Wang, X., Organocatalyzed Ring-Opening Polymerization of Cyclic Lysine Derivative: Sustainable Access to Cationic Poly(ε-lysine)Mimics. Macromolecules 2021, 54(5), 2226-2231; reaction conditions: formaldehyde as solvent, 10wt% Pd / C as catalyst, and 25℃ as temperature; the test results are listed in Table 4.

[0228] Table 3

[0229]

[0230] Table 4

[0231]

[0232]

[0233] Note: 3-Methylaminocaprolactam selectivity = methylaminocaprolactam selectivity + dimethylaminocaprolactam selectivity.

[0234] As shown in Tables 3-4, the preparation method of methylated aminocaprolactam provided by this invention does not involve alkylating agents such as aldehydes and halogenated hydrocarbons in the reaction, and has a high degree of greenness in the reaction pathway. By adjusting the type of support and the content of active components in the catalyst, as well as the ratio of reactants, it is more conducive to improving the catalytic effect of the catalyst and obtaining highly selective methylated aminocaprolactam (i.e., methylaminocaprolactam and dimethylaminocaprolactam).

[0235] Comparing the data from Examples 1-18, it can be seen that when the dual active components in the catalyst are selected from PtIn, it is more beneficial to improve the selectivity of methylated aminocaprolactam.

[0236] Compared to Examples 9-15 and 18, Examples 1-8 use a silicon-modified alumina carrier with a Brønsted acid density ≤2 μmol / g, which is more conducive to improving the selectivity of methylated aminocaprolactam.

[0237] Examples 19-22

[0238] The method is the same as in Example 1, except that...

[0239] The conditions and process parameters of the methylation reaction are listed in Table 5. The catalytic reaction results were analyzed by gas chromatography and the test results are listed in Table 6.

[0240] Comparative Example 2

[0241] The method is the same as in Example 1, except that...

[0242] The conditions and process parameters of the methylation reaction are listed in Table 5. The catalytic reaction results were analyzed by gas chromatography and the test results are listed in Table 6.

[0243] Table 5

[0244]

[0245] Table 6

[0246]

[0247] Note: 3-Methylaminocaprolactam selectivity = methylaminocaprolactam selectivity + dimethylaminocaprolactam selectivity.

[0248] As can be seen from the data in Tables 5-6, the preparation method of methylated aminocaprolactam provided by the present invention effectively improves the selectivity of methylated aminocaprolactam by controlling the conditions (temperature and pressure) of the methylation reaction and the amount of catalyst within the preferred protection range.

[0249] Compared to Example 1, Example 22 uses a higher methylation reaction temperature, which is more conducive to improving the selectivity of methylated aminocaprolactam.

[0250] 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 inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A method for preparing methylated aminocaprolactam, characterized in that, In the presence of a catalyst, aminocaprolactam and / or its derivatives are contacted with methanol and subjected to a methylation reaction to obtain methylated aminocaprolactam; Wherein, aminocaprolactam and / or its derivatives are selected from aminocaprolactam and / or aminocaprolactam salts; The methylated aminocaprolactam includes methylaminocaprolactam and / or dimethylaminocaprolactam; The catalyst is a metal-supported catalyst, selected from at least one of two-component supported catalysts and one-component supported catalysts. The support is selected from at least one of silicon-modified alumina, Al2O3, CeO2, and TiO2; The two-component supported catalyst includes a first active component and a second active component, which exist in an alloy form; the first active component is selected from noble metal elements; and the second active component is selected from non-noble metal elements. The active component of the single-component supported catalyst is selected from Pt.

2. The preparation method according to claim 1, wherein, The mass ratio of aminocaprolactam and / or its derivatives to the catalyst is 1:0.1-10; And / or, the aminocaprolactam 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.

3. The preparation method according to claim 2, wherein, The mass ratio of aminocaprolactam and / or its derivatives to the catalyst is 1:0.1-5; And / or, the aminocaprolactam 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.

4. The preparation method according to claim 3, wherein, The mass ratio of aminocaprolactam and / or its derivatives to the catalyst is 1:0.5-2; And / or, the aminocaprolactam 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.

5. The preparation method according to any one of claims 1-4, wherein, The ratio of the amount of aminocaprolactam and / or its derivatives in g to the amount of methanol in mL is 1:5-1000.

6. The preparation method according to claim 5, wherein, The ratio of the amount of aminocaprolactam and / or its derivatives in grams to the amount of methanol in mL is 1:20-500.

7. The preparation method according to claim 6, wherein, The ratio of the amount of aminocaprolactam and / or its derivatives in g to the amount of methanol in mL is 1:80-300.

8. The preparation method according to any one of claims 1-4 and 6-7, wherein, The conditions for the methylation reaction include: a temperature of 50-180℃, a time of 0.5-24h, and a pressure of 0.1-10MPa.

9. The preparation method according to claim 8, wherein, The conditions for the methylation reaction include: a temperature of 60-120℃, a time of 1-5h, and a pressure of 0.5-2MPa.

10. The preparation method according to any one of claims 1-4, 6-7 and 9, wherein, Based on the total weight of the two-component supported catalyst, the content of the first active component is 0.1-10 wt%; the content of the second active component is 0.1-20 wt%. The first active component is selected from at least one of Pd, Pt, Ru, Ir and Rh; The second active component is selected from at least one of Ni, Co, In, Sn, Ga, Zn, Mn and Fe.

11. The preparation method according to claim 10, wherein, Based on the total weight of the two-component supported catalyst, the content of the first active component is 0.2-5 wt%; the content of the second active component is 0.5-10 wt%. The first active component is selected from Pd and / or Pt; The second active component is selected from at least one of Ni, In, Ga and Zn.

12. The preparation method according to claim 1, wherein, The Brønsted acid density of the silicon-modified alumina is ≤2 μmol / g; And / or, the silicon-modified alumina comprises silicon and alumina, wherein the silicon-alumina ratio of the silicon-modified alumina is <1, the silicon is connected to the surface of the alumina by Si-O-Al chemical bonds, and adjacent silicon atoms on the surface of the alumina are connected by Si-O-Si chemical bonds. And / or, based on the total weight of the silicon-modified alumina, the alumina content is 50-90 wt%; with SiO2 as the main component. x The silicon content is calculated to be 10-50 wt%, wherein 1 ≤ x ≤ 2; And / or, the specific surface area of ​​the silicon-modified alumina is 100-220 m² / g. 2 / g; average pore size is 10-30nm; wear index is 1-20%; crushing strength is 50-150N / cm.

13. The preparation method according to claim 12, wherein, The density of the Brønsted acid in the silicon-modified alumina is 0-2 μmol / g; And / or, based on the total weight of the silicon-modified alumina, the alumina content is 70-80 wt%; with SiO2 as the main component. x The silicon content is calculated to be 20-30 wt%, wherein 1 ≤ x ≤ 2; And / or, the specific surface area of ​​the silicon-modified alumina is 120-200 m² / g. 2 / g; average pore size is 15-25nm; wear index is 1-15%; crushing strength is 70-130N / cm.

14. The preparation method according to claim 13, wherein, When the carrier is selected from the silicon-modified alumina, the Brønsted acid density of the silicon-modified alumina is 0-1.4 μmol / g.

15. The preparation method according to claim 14, wherein, When the carrier is selected from the silicon-modified alumina, the Brønsted acid density of the silicon-modified alumina is 0-0.5 μmol / g.

16. The preparation method according to any one of claims 1-4, 6-7, 9, and 11-15, wherein, The silicon-modified alumina is prepared by the following method: S1. The aluminum source, acidic compound and water are mixed in the first mixture, and the resulting first mixture is successively shaped, dried and calcined to obtain shaped alumina; S2. Dissolve the shaped alumina in water, first add an alkaline compound to adjust the pH to 7-12, then add a silicon source for a second mixing to obtain a second mixture; S3. The second mixture is subjected to solid-liquid separation, and the obtained modified alumina precursor is subjected to a second drying and a second calcination to obtain the silicon-modified alumina.

17. The preparation method according to any one of claims 1-4, 6-7, 9 and 11-15, wherein, The two-component supported catalyst was prepared by the following method: (I-1) A first soluble metal salt is loaded onto the surface of the support, and the resulting first intermediate is subjected to a third drying and a third calcination to obtain a single-component supported catalyst. (I-2) A second soluble metal salt is loaded onto the surface of the single-component supported catalyst, and the resulting second intermediate is subjected to a fourth drying and a fourth calcination to obtain the two-component supported catalyst. or, (II) The first soluble metal salt and the second soluble metal salt are loaded on the surface of the support, and the resulting third intermediate is subjected to a fifth drying and a fifth calcination in sequence to obtain the two-component supported catalyst; The third, fourth, and fifth calcinations are each carried out independently in a hydrogen-containing atmosphere.

18. The preparation method according to claim 17, wherein, The hydrogen content in the hydrogen-containing atmosphere is ≥10% by volume; And / or, the loading of the first soluble metal salt, based on the metal element, is 0.1-10 wt%; And / or, the loading of the second soluble metal salt, based on the metal element, is 0.1-20 wt%; And / or, the conditions for the third, fourth and fifth calcinations each independently include: a temperature of 400-800℃; and a time of 1-10h.

19. The preparation method according to claim 18, wherein, The hydrogen content in the hydrogen-containing atmosphere is 20-90% by volume. And / or, the loading of the first soluble metal salt, based on the metal element, is 0.2-5 wt%; And / or, the loading of the second soluble metal salt, based on the metal element, is 0.5-10 wt%; And / or, the conditions for the third, fourth and fifth calcinations each independently include: a temperature of 450-750°C; The time is 1-5 hours.

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