44 results about "Dimethylaniline N-oxide" patented technology

The invention discloses a method for extracting and separating N-methylaniline and N, N-dimethylaniline, and relates to the technical field of organic compound separation.The method comprises the steps that a reaction product of aniline and methyl alcohol is taken and fed into an adsorption refiner to be adsorbed, and a mixture A is obtained; feeding the mixture A into a light component removal tower for light component removal, collecting at the top of the light component removal tower to obtain light components, feeding the light component removal tower into a heavy component removal tower for heavy component removal, and collecting at the top of the heavy component removal tower to obtain a mixture B; taking the mixture B, feeding from the middle part of an extractive distillation tower, taking an extracting agent, feeding from the upper part of the extractive distillation tower, and performing extractive distillation; collecting the N, N-dimethylaniline at the top of the extractive distillation tower to obtain N, N-dimethylaniline, and collecting the N, N-dimethylaniline at the bottom of the extractive distillation tower to obtain an N-methylaniline mixed solution; feeding the N-methylaniline mixed solution into a desorption tower for desorption; collecting at the top of the desorption tower to obtain N-methylaniline, and collecting at the bottom of the desorption tower to obtain the extracting agent.

The application discloses a synthesis method of 2,3,3',4'-biphenyl tetracarboxylic dianhydride, characterized in that 2,3-dimethylaniline is used as a starting raw material, 2,3-dimethylaniline diazonium salt is prepared through a diazotization reaction, then 2,3,3',4'-tetramethyl biphenyl is prepared through a coupling reaction of the 2,3-dimethylaniline diazonium salt and o-xylene under the catalysis of cuprous chloride, and finally 2,3,3',4'-biphenyl tetracarboxylic dianhydride is prepared through an oxidation reaction and dehydration to form anhydride. The coupling reaction in the synthesis method has good selectivity, 3,3,4',4'-tetramethyl biphenyl which is difficult to separate is not generated, high-purity a-BPDA can be finally obtained, and the coupling reaction in the synthesis method only needs to use low-cost cuprous chloride as a catalyst, so that the production cost is greatly reduced compared to a high-cost catalytic system in the prior art, and the synthesis method is more suitable for industrial mass production.

This invention relates to the field of polyaniline derivative preparation technology, and more particularly to a green preparation method for poly(2,3-dimethylaniline). The green preparation method provided by this invention includes mixing a reaction mother liquor for preparing poly(2,3-dimethylaniline), a nitric acid solution, and 2,3-dimethylaniline, and then adding Fe... 3+ The catalyst is subjected to a first heat treatment, hydrogen peroxide is added, and a second heat treatment is performed to obtain a first-use reaction mother liquor and a filter cake. The filter cake is post-treated to obtain the poly-2,3-dimethylaniline. The first-use reaction mother liquor is recycled according to the above process. During the above recycling process, when the COD content in the reaction mother liquor obtained after recycling is greater than 29000 mg / L, the molar ratio of H2O2 to 2,3-dimethylaniline in hydrogen peroxide is increased based on the molar ratio of H2O2 to 2,3-dimethylaniline in hydrogen peroxide during the first recycling process. The preparation method has high yield and is environmentally friendly.

This invention belongs to the field of coating technology and relates to a high-temperature resistant CHPO curable putty and its preparation method, which comprises the following components: unsaturated polyester resin, styrene, cobalt isooctanoate, dimethylaniline, high-temperature resistant composite dispersant, hydrogenated castor oil, silica, rutile titanium dioxide, talc, and curing agent.

This invention belongs to the field of stone adhesive technology, specifically relating to a transparent stone splicing adhesive and its preparation method. The adhesive comprises a resin component and a curing component. The resin component includes maleic anhydride, phthalic anhydride, diol, catalyst, polymerization inhibitor, and crosslinking monomers, etc., and the diol includes at least 1,2-propanediol. The curing component includes an accelerator composed of dimethylaniline and zinc adipate, and a benzoyl peroxide initiator. The adhesive of this invention is colorless and transparent after curing, exhibits excellent resistance to yellowing, is easy to apply, and after curing with fillers, possesses excellent shear strength, water shear strength, and impact resistance. It can be widely used in high-end stone splicing, repair, and craft bonding.

The invention discloses a catalyst for preparing N-(1-ethyl propyl)-3, 4-dimethylaniline through continuous catalytic hydrogenation and a preparation method and application thereof, the catalyst comprises a carrier, and an active component platinum and an auxiliary component which are loaded on the carrier, the auxiliary component is at least one of sodium citrate, disodium ethylene diamine tetraacetate, sodium metavanadate, oxalic acid, zirconium oxychloride, yttrium nitrate or sodium carbonate; and the active component and the auxiliary component both account for 0.1-10% of the mass of the catalyst. The catalyst is used for preparing N-(1-ethyl propyl)-3, 4-dimethylaniline through hydrogenation, the reaction can be continuous, the safety performance is better, and the catalyst has high catalytic activity and stability.

This invention relates to a toothpaste flavoring with a long-lasting fresh breath effect and its preparation method. The core component of this toothpaste flavoring is modified menthol. Modified menthol reacts with amino acid compounds to form a menthol-amino acid complex, which is then coated with β-cyclodextrin to form a menthol-amino acid-β-cyclodextrin complex. This dual synergistic effect effectively prolongs the duration of its fresh breath effect. The toothpaste flavoring also includes 2,6-dimethylaniline, flavor enhancers, emulsifiers, stabilizers, aroma retardants, and preservatives to ensure aroma stability and safety for oral use. This invention provides a longer-lasting fresh breath effect, solving the problems of rapid evaporation and short-lasting freshness in traditional toothpaste flavorings, and has good market application prospects.

The present invention relates to the technical field of concrete materials. Disclosed are a modified epoxy resin and a preparation method therefor, a composition for an epoxy resin grouting material, an epoxy resin grouting material, a preparation method therefor, and a use thereof. The method for preparing the modified epoxy resin comprises: heating a polyhydroxy compound and an epoxy resin at 80-100ºC in a nitrogen atmosphere in the presence of a catalyst to obtain the modified epoxy resin, wherein the molar ratio of the polyhydroxy compound, the epoxy resin, and the catalyst is 1:1-2:0.05-0.1; the epoxy resin is a bisphenol A epoxy resin; the catalyst is selected from any one of sodium hydroxide, potassium carbonate, and dimethylaniline; and the polyhydroxy compound is selected from at least one of glycerol, ethylene glycol, propylene glycol, glucose, and butylene glycol. The epoxy resin grouting material of the present invention has more excellent toughness and lower viscosity, and good bonding strength and bonding durability with a concrete matrix.

The application provides a low-yellowing fluorine-free semi-alicyclic polyimide composition and a preparation method thereof, and relates to the technical field of polyimide preparation.The semi-alicyclic polyimide composition is prepared by polymerization reaction of diamine and dianhydride; the diamine comprises first diamine and second diamine; the first diamine is 4,4'-diamino diphenyl ether-2,2'-disulfonic acid and / or 4-(4-aminophenoxy)-2,6-dimethyl aniline; the second diamine is 4,4'-diamino dicyclohexyl methane and / or 3,3'-dimethyl-4,4'-diamino dicyclohexyl methane; and the dianhydride is fluorine-free dianhydride. The semi-alicyclic polyimide composition prepared by the application significantly improves the optical performance of the polyimide film prepared therefrom, and the anti-yellowing effect is significantly improved.

The invention discloses a waterproof fiber composite board and a preparation method thereof, and belongs to the technical field of fiber composite boards. The preparation method comprises the following steps: mixing and stirring fir wood fibers, maleic anhydride, benzoyl peroxide and N, N-dimethylaniline for reaction to obtain pretreated wood fibers; the pretreated wood fibers and phenolic resin with the solid content being 50% are mixed to obtain a wood matrix material, modified pollen, modified lotus leaf wax, stannous octoate and modified aerogel are added, and the mixture is stirred and mixed to obtain functional slurry; and pouring the functional slurry into a mold, and carrying out hot pressing treatment to obtain the waterproof fiber composite board. Chemical bonding of the modified aerogel, the pretreated wood fiber and the modified pollen is achieved through an isocyanate group, and a continuous heat preservation network is constructed to achieve the heat preservation property; phenolic resin, modified pollen and modified lotus leaf wax form double waterproof barriers, so that the problem that hydrophobic components are easy to migrate is solved; all the components have a synergistic effect, so that the product has excellent water resistance, antibacterial property, thermal insulation property, mechanical property and thermal stability.

The application provides a double-curing acrylate-epoxy hybrid adhesive as well as a preparation method and application thereof, and belongs to the technical field of adhesives. The double-curing acrylate-epoxy hybrid adhesive is composed of component A and component B. The component A comprises tetrahydrofurfuryl methacrylate, isobornyl methacrylate, hydroxypropyl methacrylate, N,N-dimethylaniline, a toughening agent, a double-curing resin, wollastonite, fumed silica, solid glass microbeads, an antioxidant, a phosphate monomer and a multifunctional monomer. The component B comprises benzoyl peroxide, an epoxy resin, wollastonite and fumed silica. The double-curing acrylate-epoxy hybrid adhesive prepared by the application can realize the combination of high-temperature strength and normal-temperature toughness, and solves the problem of easy gelation of a traditional NCO-containing system.

This invention discloses a berberine-dimethylaniline photosensitizer, its preparation method, and its application, belonging to the field of biomedical technology. The method involves sequentially reacting berberine with magnesium methyl bromide via Grignard addition, followed by bromomethylation with N-bromosuccinimide, and basic condensation with dimethylaminobenzaldehyde, then demethylating under high temperature and vacuum to obtain the active berberine-dimethylaniline. Finally, it undergoes weakly alkaline treatment to obtain the inactivated berberine-dimethylaniline. This invention introduces the electron-donating group dimethylaniline onto the berberine backbone, constructing an electron push-pull structure that red-shifts the absorption wavelength, facilitating deeper tissue penetration. Furthermore, this photosensitizer maintains high activity in the weakly acidic microenvironment of tumors while remaining inactive under normal physiological conditions, thereby achieving intelligent "on-off" regulation based on pH differences, improving the safety and precision of photodynamic therapy for tumors.

The invention relates to a multi-tower rectification method and a multi-tower rectification system. The multi-tower rectification method comprises the following steps that a fresh material to be separated is introduced into a first rectification tower to be subjected to first rectification treatment, a tower top gas-phase product and a first tower bottom product are formed, and the mass content of N, N-dimethylaniline in the first tower bottom product is 2%-9%; the tower top gas-phase product passes through a second reboiler to release heat, and after a second rectifying tower is heated, a first tower top product is formed; the first tower bottom product is introduced into a second rectifying tower to be subjected to second rectifying treatment, a second tower top product and a second tower bottom product are formed, and the mass content of N-methylaniline in the second tower top product is larger than or equal to 20%. On the basis of reducing the overall energy consumption cost, a high-purity product can be obtained.

The invention discloses a preparation method of a vitamin B2 diastereoisomer, which comprises the following steps: adding absolute ethyl alcohol into a high-pressure reaction kettle, adding 3, 4-dimethylaniline, D-arabinose and palladium carbon in a stirring state, introducing hydrogen, heating for reaction, and filtering while hot; cooling, crystallizing and filtering the filtrate, collecting a filter cake, dissolving the filter cake with a hydrochloric acid aqueous solution, adding aniline diazonium salt in a stirring state, after the reaction is completed, adding sodium acetate for crystallizing and filtering, and adding the filter cake into a mixed solution of a solvent A and barbituric acid for reflux reaction; cooling to room temperature and filtering to obtain a vitamin B2 diastereoisomer crude product; adding inorganic acid B into the crude wet filter cake for dissolving, adding into hot water, filtering while hot, and drying the diastereoisomer of the vitamin B2. The whole process steps are simple and easy to operate, all the raw materials required for preparation are common and easily available raw material substances, and meanwhile, the vitamin B2 diastereoisomer prepared by the whole preparation process is relatively high in purity, so that the whole preparation efficiency and quality are ensured.

The invention discloses a high-temperature-resistant high-resilience self-repairing polyurethane elastomer and a preparation method thereof, and relates to the technical field of self-repairing. The preparation method comprises the following steps: taking polytetrahydrofuran glycol, vacuumizing and dehydrating; introducing nitrogen, adding isophorone diisocyanate and dibutyltin dilaurate, and carrying out a reaction so as to obtain a polyurethane prepolymer; taking a polyurethane prepolymer, introducing nitrogen, adding a chain extender A and a chain extender B, stirring, adding the mixed solution, and stirring; adding a metal salt solution and N, N-dimethylaniline, and uniformly mixing; putting the mixture into a polytetrafluoroethylene mold, reacting, vacuumizing, removing bubbles, curing, cooling and demolding to obtain the high-temperature-resistant high-resilience self-repairing polyurethane elastomer. Amino groups of 2, 6-diaminopyridine react with isocyanate groups of the polyurethane prepolymer, and 2, 6-diaminopyridine and metal ions in the metal salt solution are coordinated to form metal coordination bonds, so that the high-temperature resistance, resilience and self-repairing performance of the polyurethane elastomer are improved.

The invention discloses a continuous reaction research process of low-biphenylamine impurity 2, 4-dimethyl-bis-acetanilide, and belongs to the field of chemical synthesis. The invention aims to provide the continuous reaction research process for the low-bis-phenylamine impurity 2, 4-dimethyl-bis-acetanilide (2, 4-dimethyl-N-acetoacetanilide), the retention time of the 2, 4-dimethyl-N-acetoacetanilide raw material is shortened, the bis (2, 4-dimethyl phenyl) amine impurity is reduced, the yield of the 2, 4-dimethyl-N-acetoacetanilide is increased, and the production cost is reduced. Meanwhile, the auto-polymerization of the diketene is reduced, the consumption of the 2, 4-dimethylaniline is reduced, and the problems of high impurity content of the bis (2, 4-dimethylphenyl) amine in the existing 2, 4-dimethyl-N-acetoacetanilide and poor batch stability are solved.

The invention belongs to the technical field of pharmaceutical preparations, and relates to lidocaine hydrochloride gel and a preparation method thereof, and the preparation method comprises the following steps: 1) dissolving and dispersing a bacteriostatic agent and a gel matrix with water, and sterilizing to obtain a gel solution; 2) dissolving lidocaine hydrochloride with water, adjusting the pH value of the solution, and performing rapid heating and cooling sterilization to obtain a lidocaine hydrochloride solution; and (3) adding a lidocaine hydrochloride solution into the gel solution under a sterile condition, and stirring and mixing the lidocaine hydrochloride solution and the gel solution. By adjusting and changing the production and preparation process of lidocaine hydrochloride, the exposure time of lidocaine under a high-temperature condition is reduced, the degradation of lidocaine is further reduced, the content level of 2, 6-dimethylaniline is effectively reduced, the stability and quality of the product are improved, and toxic and side effects on patients are reduced; and the production process is simple and convenient to operate, the production time of the lidocaine hydrochloride gel is shortened, the working efficiency is improved, and the cost is saved.

The present disclosure provides for methods of producing analgesia in a subject. In some cases, methods produce analgesia in a subject undergoing arthroscopic subacromial decompression surgery. The present disclosure also relates to improved sustained release drug delivery systems. In some cases, a composition comprises an active pharmaceutical agent; at least one of sucrose acetate isobutyrate and a polyorthoester; an organic solvent; and 2,6-dimethylaniline, wherein the 2,6-dimethylaniline is present at a level less than 500 ppm. In some cases, a composition comprises bupivacaine N-oxide at a level less than 1 wt %, based on weight of the composition. In some cases, a composition comprises metal present at a level less than 5 ppm. Dosage forms and methods are also provided.

The application belongs to the technical field of organic polymer compound preparation, and relates to an oilfield water injection and polymer injection glass steel pipeline material and a preparation method, which comprises, from inside to outside, an anticorrosive wear-resistant inner layer and a high-pressure anti-aging outer layer; the anticorrosive wear-resistant inner layer comprises epoxy vinyl ester resin, graphene-polytetrafluoroethylene composite powder, nano silicon dioxide, nano zinc oxide, isothiazolinone microbial inhibitor, methyl tetrahydrophthalic anhydride curing agent and dimethyl aniline accelerator; the high-pressure anti-aging outer layer comprises bisphenol A type epoxy resin, phenolic resin, surface modified glass fiber, nano silicon carbide, aromatic amine curing agent, triethanolamine accelerator, polysulfide rubber toughening agent, ultraviolet absorber, antioxidant and nano boron nitride; through overall cooperation of component matching and process improvement, the performance is obviously improved, the oilfield water injection and polymer injection complex working conditions are adapted, and a plurality of technical shortcomings of the existing glass steel pipeline are solved.

The invention belongs to the technical field of organic synthesis, and particularly relates to a preparation method of novel tiamulin fumarate. The preparation method comprises the following steps: reacting pleuromutilin with thionyl chloride to generate chlorinated pleuromutilin; reacting the chlorinated pleuromutilin with thiourea, and carrying out alkali treatment, so as to generate sulfhydrylated pleuromutilin; the preparation method comprises the following steps: reacting sulfhydrylated pleuromutilin with 2-bromo-N, N-diethyl ethyl-1-amine to form tiamulin, and finally carrying out a salt forming reaction. The invention provides a synthetic route of chlorination, sulfhydrylation, alkylation and salification, and two key intermediates, namely the chlorinated pleuromutilin and the sulfhydrylated pleuromutilin, are prepared step by step, so that the accurate control of the reaction process is realized. Wherein the chlorination reaction is catalyzed by N, N-dimethylaniline, the low-temperature staged reaction is adopted, and the selectivity is good; thiourea is used for alkaline hydrolysis in sulfhydrylation, so that foul mercaptan is avoided; alkylation is carried out under weak base and low temperature; no controlled reagent is needed in the whole process, and green chemical requirements are met.

The invention relates to the technical field of hydrogel, in particular to hydrogel based on an acrylonitrile acrylamide copolymerization system and a preparation method of the hydrogel. The preparation method comprises the following steps: preparing a copolymerization solution by taking an acrylonitrile monomer and an acrylamide monomer as raw materials, wherein the molar ratio of the acrylonitrile monomer to the acrylamide monomer is (3: 7)-(5: 5); an initiator is added into the copolymerization liquid, the mixture is subjected to a polymerization reaction at the temperature of 40-50 DEG C, organogel is obtained, and the initiator is composed of dibenzoyl peroxide and N, N-dimethylaniline according to the molar ratio of 1: 1; and replacing the solvent in the organic gel with water. Compared with the prior art, the preparation method has the advantages that acrylamide is utilized to construct a high-hydrophilicity and high-entanglement network framework, so that the material is ensured to have good flexibility and ductility; meanwhile, an acrylonitrile monomer containing a strong-polarity cyano group is introduced, and a high-strength physical cross-linking area is dynamically constructed under the action of external force through dipole-dipole interaction formed by the acrylonitrile monomer, so that network dynamic enhancement and strain hardening response are realized.

The present invention provides a mepivacaine preparation method, which comprises that in an organic solvent, 1-methylpiperidine-2-formic acid and 2, 6-dimethylaniline are subjected to a condensation reaction in the presence of a condensing agent to obtain mepivacaine, and the condensing agent is selected from one or more of phosphorus oxychloride, phosphorus trichloride and phosphorus pentachloride. The condensing agent used for preparing mepivacaine is one or more of phosphorus oxychloride, phosphorus trichloride and phosphorus pentachloride, toxic substances such as phosgene and the like are not generated, the safety is high, the cost is low, and the preparation method is suitable for industrial popularization.

The invention relates to the technical field of preparation of alkylation catalysts, and discloses an alkylation catalyst, a preparation method and application thereof, and a synthesis method of N, N-dimethylaniline. The invention relates to an alkylation catalyst, which comprises Cu, an auxiliary active component and a carrier, the auxiliary active component is selected from at least one of VIII group metal and VIB group metal; the carrier comprises a molecular sieve and a binder; wherein the ratio of Cu < + > to Cu < 2 + > in the catalyst is 0.1-0.4. The catalyst has a specific Cu < + > / Cu < 2 + > ratio, and the activity, the stability and the service life of the catalyst can be improved.

The invention discloses low-moisture ceramic slurry and a low-moisture ceramic diaphragm, and belongs to the technical field of battery diaphragms. The low-moisture ceramic slurry is prepared from the following components in parts by mass: 25 to 55 parts of a hydrophobic modified ceramic material, 1 to 10 parts of a thickening agent, 8 to 20 parts of a high-temperature-resistant binder, 0.05 to 0.1 part of a wetting agent, 1 to 5 parts of a dispersing agent and 25 to 50 parts of a solvent, the solvent is ultrapure water; the hydrophobic modified ceramic material is obtained by modifying aluminum oxide with a hydrophobic silane coupling agent, and the hydrophobic silane coupling agent is obtained by reacting 4-allyl-N, N-dimethylaniline with 3-mercaptopropyltrimethoxysilane, and the hydrophobic silane coupling agent is obtained by reacting 4-allyl-N, N-dimethylaniline with 3-mercaptopropyltrimethoxysilane. The high-temperature-resistant adhesive is obtained by polymerizing butyl acrylate, acryloyloxybenzophenone and hydroxypropyl acrylate; the prepared low-moisture ceramic slurry is good in high temperature resistance, and a low-moisture ceramic diaphragm prepared from the low-moisture ceramic slurry is high in ionic conductivity.

This invention discloses a poly(2,5-dimethylaniline), its preparation method, and its applications, belonging to the field of polymer materials technology. First, deionized water, an inorganic acid, and 2,5-dimethylaniline are stirred and mixed evenly; then, ammonium persulfate solution is slowly added dropwise to initiate a polymerization reaction; after a certain time of isothermal polymerization, the mixture is filtered, washed, dried, and ground to obtain the poly(2,5-dimethylaniline). The poly(2,5-dimethylaniline) prepared by this invention has a high corrosion potential, the raw materials are readily available, the preparation method is simple and easy to implement, and it has broad development prospects.

The invention relates to the technical field of organic synthesis, and particularly discloses a method for preparing triisopropyl phosphite. According to the method, phosphorus trichloride and isopropanol are used as raw materials, and triethylamine, N, N-dimethylaniline or potassium carbonate is used as an acid-binding agent to carry out esterification reaction in an inert solvent under the protection of inert gas. The reaction is carried out under the mild condition of 0-30 DEG C, and then a high-purity product is obtained through filtration, solvent recovery and reduced pressure distillation. The green acid-binding agent is adopted to replace traditional toxic pyridine, the problems of environmental pollution and equipment corrosion are fundamentally solved, meanwhile, reaction conditions are mild, aftertreatment is simple, the product yield is high (can reach 92%), the purity is good (larger than or equal to 98.5%), the solvent can be recycled, and the method is particularly suitable for industrial production.

The application discloses a catalyst for continuously preparing N-(1-ethylpropyl)-3,4-dimethylaniline through hydrogenation as well as a preparation method and application thereof. The catalyst comprises a carrier, and an active metal Pt, a first additive and a second additive supported on the carrier; the first additive is one of Sb, V, Zr, Ti and W, and the second additive is one of Bi, Co, Zn, Mn and La; the content of each component in the catalyst with a mass of 100% is as follows: the active metal Pt is 0.5-5%, the first additive is 0.1-1%, the second additive is 0.05-0.2%, and the rest is the carrier. The carrier is pretreated by using the additive metal, so that the catalyst has excellent anti-sintering and anti-carbon deposition capacity in continuous operation, and has a long service life; when the N-(1-ethylpropyl)-3,4-dimethylaniline is prepared, a continuous flow fixed bed technology is adopted, and production efficiency is high.

The invention relates to the field of rubber, and discloses rubber processing modified masterbatch, a preparation method and application thereof, a rubber composition, vulcanized rubber and a preparation method thereof, the rubber processing modified masterbatch comprises maleic acid series monomers, dicumyl peroxide, butadiene styrene rubber, white oil and N, N-dimethylaniline; wherein relative to 100 parts by weight of butadiene styrene rubber, the content of the maleic acid series monomer is 133 to 400 parts by weight, the content of the dicumyl peroxide is 10 to 67 parts by weight, the content of the white oil is 17 to 100 parts by weight, and the content of the N, N-dimethylaniline is 7 to 40 parts by weight; the modified rubber master batch for rubber processing can improve the compatibility and dispersity of maleic acid series monomers in a rubber matrix, so that the strength and wet skid resistance of vulcanized rubber are improved, and the rubber master batch is good in flexing resistance.

The present application relates to rubber antioxidant intermediate p-aminodiphenylamine production field, especially disclose a method for step-by-step condensation reaction of aniline-nitrobenzene, the present application adopts the combination form of multiple condensation reaction kettle series-parallel connection to constitute two sections (stage) type continuous reaction system, according to the reaction characteristics, condensation catalyst and aniline are proportioned and added to two section reaction system respectively, reduce the accumulation of condensation catalyst in the system in the initial stage of reaction, improve the combination efficiency of aniline and condensation catalyst and the condensation reaction efficiency of aniline ion and nitrobenzene, inhibit the decomposition of condensation catalyst, the present application can effectively reduce the consumption of condensation catalyst without adding additional additives, inhibit the occurrence of condensation side reaction, especially reduce the generation of N-methylaniline and N, N-dimethylaniline, reduce the generation of trimethylamine waste gas, significantly increase the safety and economy of the process.

The invention discloses a method for preparing 2, 4-dimethylaniline through direct ammonification of 2, 4-dimethylphenol. Comprising the following steps: contacting a raw material of 2, 4-dimethylphenol with a catalyst, and reacting in the presence of an ammonia source to obtain a product containing 2, 4-dimethylaniline, the catalyst is a nickel modified ZSM-12 molecular sieve. According to the present invention, 2, 4-dimethylaniline is prepared from 2, 4-dimethylphenol through a new path by using a one-step method, the catalyst is prepared by using a simple impregnation method, the catalyst comprises non-noble metal nickel and a ZSM-12 molecular sieve, and the metal and the carrier of the catalyst interact so as to produce 2, 4-dimethylaniline with high selectivity; the method has the advantages of low catalyst cost, simple process route, low reaction pressure and low equipment investment, and is suitable for large-scale and long-period continuous production.