73 results about "Methylaniline" 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 provides a process and equipment for removing m-methylaniline and indole in coking nanofiltration concentrated water, a catalyst and a preparation method thereof, and the water quality of the coking nanofiltration concentrated water is as follows: conductivity 21300-34560 muS / cm, sulfate ion 567-1340 mg / L, m-methylaniline 45-78 mu g / L, and indole 23-39 mu g / L; the process comprises the following treatment steps: the coking nanofiltration concentrated water enters the ozone catalytic tower from the bottom of the tower and flows out from bottom to top, and the ozone catalytic tower is internally provided with a modified peanut shell biochar catalyst; after the ozone catalytic reaction, the water quality of the coking nanofiltration concentrated water is as follows: conductivity 21300-34560 muS / cm, sulfate ion 567-1340 mg / L, m-methylaniline 3-7 mu g / L, and indole 1-6 mu g / L.

The application discloses a catalyst for preparing methylaniline and a preparation method and application thereof, and belongs to the technical field of catalysts. The catalyst is prepared by modifying an activated carbon carrier with zirconium, cerium or nickel, treating the carrier with high-temperature nitrogen, loading active components Pd and pH-responsive polymers, solving the problems of low dispersion of the active components, easy poisoning and activity attenuation, and having good pH responsiveness and environmental adaptability. The preparation method optimizes a carrier modification process, adopts an impregnation method combined with timed stirring, controls reaction parameters, improves catalyst performance, realizes high selectivity and high yield of methylaniline, and has the advantages of high selectivity of the catalyst for methylaniline, inhibition of side reactions, adoption of a fixed bed reactor, simplification of operation, reduction of safety hazards, efficient reaction at a lower reaction temperature and pressure, and reduction of energy consumption and production cost.

The invention relates to the technical field of zinc-silver batteries, in particular to a zinc-silver battery electrolyte additive, a zinc-silver battery electrolyte and a zinc-silver secondary battery. A trace amount of negatively-charged surfactant N-ethyl-N-(3-sulfopropyl)-3-methylaniline sodium salt is added into the traditional KOH electrolyte of the zinc-silver secondary battery, and the problem of deformation of a zinc negative electrode caused by the existence of a free-state charge-discharge intermediate product Zn (OH) 4 < 2-> is inhibited by utilizing specific adsorption of amphoteric molecules and a negatively-charged functional group. The additive not only can stabilize the zinc negative electrode structure and improve the cycle performance of the zinc-silver battery, but also can enable the active substances in the zinc-silver battery to give full play to the capacity, and prolongs the service life of the zinc-silver secondary battery for repeated and stable discharge and energy supply.

The invention discloses a preparation process of 2-chloro-4-(methylsulfonyl)-3-methyl benzoic acid, and relates to the technical field of preparation of inorganic compounds. The invention relates to a preparation process of 2-chloro-4-(methylsulfonyl)-3-methyl benzoic acid, which comprises the following steps: reacting 3-chloro-2-methylaniline with hydrochloric acid and sodium methyl mercaptide to form an intermediate C1, reacting with acetyl chloride, catalyzing with anhydrous aluminum trichloride to form an intermediate C2, reacting with hydrogen peroxide and sodium hypochlorite to form an intermediate C4, and reacting with sodium chloride to form the 2-chloro-4-(methylsulfonyl)-3-methyl benzoic acid. The 2-chloro-4-(methylsulfonyl)-3-methyl benzoic acid is obtained after the reaction is completed.

The application relates to the technical field of medicines, in particular to a preparation process of a Tucatinib intermediate 4-([1,2,4]triazolo[1,5-a]pyridin-7-yloxy)-3-methylaniline, which comprises the following steps: step 1: under a nitrogen atmosphere, a substitution reaction is carried out on a compound B and a compound C in a base and an organic solvent system to obtain a compound D; step 2: the compound D is added into a reduction catalytic solution system protected by nitrogen, after 8-30h of reaction at 70-120 DEG C, TLC tracking is carried out until the reaction is completed, 2-8 times the volume of the compound D is added into water, post-treatment and purification are carried out, and the compound A is obtained; wherein the reduction catalytic solution system comprises a reducing agent, a catalyst and an inorganic acid, the reducing agent comprises a reducing phosphoric acid, and the catalyst comprises iodine or a metal salt of iodine. The preparation process of the Tucatinib intermediate 4-([1,2,4]triazolo[1,5-a]pyridin-7-yloxy)-3-methylaniline in the application has mild reaction conditions, high product yield and high purity, the preparation process is environment-friendly, and can be used for industrial production.

The invention relates to the technical field of harmful substance detection, in particular to a three-channel colorimetric sensor for simultaneously detecting aflatoxin and a precursor thereof as well as a preparation method and application of the three-channel colorimetric sensor. According to the method, COFFe / NiP-Ph is utilized for catalyzing 3, 3 ', 5, 5'-tetramethylbenzidine (TMB) to be oxidized to generate blue oxTMB, o-phenylenediamine (OPD) is utilized for generating yellow oxOPD, and then the aflatoxin and the precursor thereof are detected through a three-channel colorimetric sensor. Purple ox4-AT is generated by using a mixture of N-ethyl-N-(3-sulfopropyl)-3-methylaniline sodium and 4-aminoantipyrine (4-AT), so that the colorimetric response is realized in a short time. The preparation method of the COFFe / NiP-Ph nano enzyme comprises the following steps: 1, a synthesis process of Fe-TAPP; 2, synthesis of Ni-TAPP is carried out; and 3, synthesizing the iron / nickel porphyrin covalent organic framework. The colorimetric sensor can be prepared into a detection reagent or a kit so as to realize qualitative and quantitative detection of aflatoxin and a precursor thereof in a sample to be detected. The detection method is simple and convenient to operate, and complex pretreatment on a to-be-detected sample is not needed; the detection cost is low, the detection is quick, and the requirement on a detection instrument is low.

The invention relates to the technical field of chemical monitoring, in particular to an N-methylaniline impurity online spectrum monitoring device which comprises a bottom rack, a plurality of glass boxes are evenly arranged on the bottom rack in the length direction, the glass boxes sequentially have different deflection angles, and the deflection angle difference values of the adjacent glass boxes are equal; by arranging the multi-angle deflection glass box, static and multi-angle static monitoring of N-methylaniline is realized, spectral characteristics of impurities in different directions can be effectively captured, and slow rotation of the glass box further drives the internal N-methylaniline to change angles, so that a light source can fully irradiate, and the detection accuracy is improved. Impurities possibly hidden due to local gathering are repeatedly exposed in dynamic rotation, a monitoring blind area is eliminated, the comprehensiveness of impurity detection is remarkably enhanced through the steps, and the accuracy of a monitoring result can be greatly improved especially for trace impurities which are not evenly distributed.

This invention relates to the field of asphalt technology and discloses a high-adhesion asphalt anti-stripping agent and its preparation method; including the following steps: Step 1: Add amino-branched titanium dioxide to N-methylaniline and mix evenly to obtain a polyamine complex; Step 2: Mix terpene phenolic resin, methyl phenyl silicone resin, and additives evenly, add the polyamine complex and calcium hydroxide, and mix evenly to obtain a high-adhesion asphalt anti-stripping agent.

The preparation method comprises the following steps: step 1, first interfacial polymerization: immersing a polysulfone support membrane into a polyamine water phase solution, taking out the polysulfone support membrane, removing a solvent, immersing the polysulfone support membrane into an acyl chloride A part hydrolyzed oil phase solution, and carrying out first interfacial polymerization reaction, so as to obtain a polysulfone membrane; a nascent state reverse osmosis membrane is obtained; step 2, secondary interfacial polymerization: removing unreacted acyl chloride from the nascent state reverse osmosis membrane, then immersing the nascent state reverse osmosis membrane into an oil phase solution of acyl chloride B to carry out secondary interfacial polymerization reaction, and then carrying out heat treatment to obtain a reverse osmosis membrane semi-finished product; and step 3, third interfacial polymerization: immersing the semi-finished reverse osmosis membrane product into an oil phase solution of o-methylaniline, carrying out third interfacial polymerization, and carrying out heat treatment again to obtain the ultra-high-desalination and anti-oxidation reverse osmosis membrane. Under the condition of ensuring that the water flux is not greatly reduced, the ultra-high desalination rate of the reverse osmosis membrane is realized, and the service life of the membrane is prolonged.

The invention discloses a Schiff base compound generated by condensation of 1-pyrenecarboxaldehyde and 4-(1, 2, 4-triazole-1-yl methyl) aniline as well as a preparation method and application of the Schiff base compound. The Schiff base compound has certain fluorescence and anti-DPPH free radical activity, and has potential application value in preparation of fluorescent materials and antioxidants.

The application belongs to the technical field of organic synthesis, and particularly relates to a preparation method of 4-amino-2-methylbenzoic acid, and more particularly relates to a preparation method of 4-amino-2-methylbenzoic acid as a raw material of a tolvaptan intermediate, wherein 3-methylaniline is used as a raw material to prepare 3-methylacetanilide with an acylating agent, the 3-methylacetanilide is subjected to Friedel-Crafts acylation with oxalyl chloride under a Lewis acid catalytic system to prepare 4-acetylamino-2-methylbenzoic acid, and finally, the 4-acetylamino-2-methylbenzoic acid is deprotected under alkaline conditions, and then acidified to obtain the target compound 4-amino-2-methylbenzoic acid, wherein the raw material used in the preparation method is cheap and easy to obtain, the production equipment has low requirements, the process condition is simple, the safety factor is high, no ammonia nitrogen and other three wastes are generated, the cost is low, and the industrialized production is easy to implement.

The application provides a preparation method of 4,4'-diamino-2,2'-dimethylbiphenyl, which comprises the following steps: under the protection of a protective gas, m-methylaniline is reacted in a mixed solvent of water and an organic solvent under the catalysis of potassium ferricyanide and an alkali to obtain 4,4'-diamino-2,2'-dimethylbiphenyl shown in formula I. The m-methylaniline is used for oxidative coupling to obtain 4,4'-diamino-2,2'-dimethylbiphenyl, the reaction steps are short, the selectivity is higher, the reaction yield is high, and the cost is lower, so that the preparation method is novel, the selectivity is good, the overall preparation cost is low, and the yield is high.

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 utility model discloses an N-methylaniline production wastewater environment-friendly treatment device which comprises a resin adsorption tank, an upper baffle and a lower baffle are arranged on the inner wall of the resin adsorption tank, a vertical shaft is rotatably installed in the resin adsorption tank and movably penetrates through the upper baffle and the lower baffle, and three partition plates are fixed outside the vertical shaft. The space between the upper baffle and the lower baffle in the resin adsorption tank is equally divided into a resin adsorbent filling bin, a first-stage filtering bin and a second-stage filtering bin through partition plates, and a first liquid inlet pipe and a second liquid inlet pipe are arranged at the top end of the resin adsorption tank. The adsorption tank is divided into the filling bin, the first-stage filtering bin and the second-stage filtering bin through the partition plates, the filling bin is used for resin replacement, the first-stage filtering bin and the second-stage filtering bin form a two-stage series adsorption structure, the rotating motor drives the vertical shaft to rotate, online transfer of adsorbents among stages is achieved, saturated resin can be replaced and regenerated in time, shutdown is not needed, and the adsorption efficiency is improved. And the processing continuity is ensured.

The invention relates to the technical field of analysis and detection, in particular to a gas chromatography-mass spectrometry detection method for N-methylaniline. The gas chromatography-mass spectrometry detection method for N-methylaniline comprises the following steps: treating a sample to be neutral, and extracting N-methylaniline in the sample by using dichloromethane to obtain a liquid to be detected; aa, separating the to-be-detected liquid through a quartz capillary column, and carrying out gas chromatography-mass spectrometry detection; the conditions of the gas chromatography are as follows: the temperature of a sample inlet is 260-280 DEG C, the initial column temperature is 40-50 DEG C, the conditions are kept for 1-5 minutes, and the temperature is increased to 200-280 DEG C at the speed of 5-30 DEG C / min; the conditions of the mass spectrum are as follows: the temperature of an ion source is 230-250 DEG C, and the temperature of a transmission line is 310 DEG C. By controlling extraction, chromatography and mass spectrometry conditions, N-methylaniline can be effectively separated from a sample, and accurate and efficient qualitative and quantitative analysis can be performed on N-methylaniline.

The application relates to the field of chemical raw material synthesis, and particularly discloses a preparation method of an ultraviolet absorber UV-1. The preparation method of the ultraviolet absorber UV-1 comprises the following steps: blending p-aminoethyl benzoate, formic acid, N-methylaniline and a catalyst, reacting at a temperature of 0-5 DEG C for 6-7 h, and obtaining the ultraviolet absorber UV-1 after vacuum distillation, wherein the catalyst is FeCl4 / MSNs. The preparation method can improve the utilization rate of raw materials, reduce the corrosion degree of equipment, and make the reaction more easily controllable, has good applicability and operability, brings remarkable optimization effect for the preparation of the ultraviolet absorber UV-1, the uniform corrosion rate of the equipment after running for three months is 0.08 mm / year, the pitting coefficient is as low as 1.1-1.4, the yield of the ultraviolet absorber UV-1 is not lower than 99.1%, and the purity of the ultraviolet absorber UV-1 is not lower than 99.5%.

This invention provides a special lubricating oil for multi-fuel spark-ignition two-stroke engines used in unmanned aerial vehicles (UAVs) and its preparation method, belonging to the field of lubricating oil technology. The special lubricating oil for multi-fuel spark-ignition two-stroke engines for UAVs comprises, by weight percentage: base oil, 66-81 wt%; additives, 15-20 wt%; and diluent, 4-14 wt%. The base oil includes hydrocarbon-based oil, polyisobutylene, and synthetic esters, wherein the hydrocarbon-based oil is a mixture of 70-85 wt% Group III hydrogenated mineral oil and 15-30 wt% Group IV hydrocarbon synthetic oil. The additives include a composite detergent-dispersant, a composite anti-adhesion detergent, a friction-reducing and anti-wear agent, an antioxidant, an octane number improver, and a compounding agent, wherein the octane number improver is N-methylaniline. The diluent is aviation kerosene.

This application discloses the application of samarium-doped zirconium-titanium composite oxides in catalyzing lactone ring-opening, amination, cyclization, and N-alkylation reactions. It belongs to the field of chemical synthesis technology. This invention uses a novel samarium-doped zirconium-titanium composite oxide as a catalyst. This catalyst possesses abundant oxygen vacancies and Lewis acid sites, enabling it to efficiently catalyze lactone ring-opening, amination, cyclization, and N-alkylation reactions, lowering the reaction energy barrier. Using this catalyst, N-butylcaprolactam, N-methylaniline, and 1-(3-methoxypropyl)-2-pyrrolidone were successfully prepared. The preparation method is simple, environmentally friendly, highly atom-economical, and suitable for large-scale production.

The invention discloses a stable lactic dehydrogenase and uric acid combined detection kit with strong anti-interference capability, and belongs to the technical field of detection. The joint detection kit comprises a reagent R1 and a reagent R2, wherein the reagent R1 contains a buffer solution, a composite anti-interference agent, a composite stabilizer, L-lithium lactate, a compound surfactant, 4-aminoantipyrine, peroxidase and a preservative diazolidinyl urea; the reagent R2 contains a buffer solution, a coenzyme (NAD < + >), N-ethyl-N-(3-sulfopropyl)-3-methylaniline sodium salt uricase, a compound stabilizer, a compound surfactant and a preservative epsilon-polylysine hydrochloride. According to the present invention, the lactic dehydrogenase detection and the uric acid detection can be simultaneously achieved by one reagent, such that the use convenience is substantially improved, and the stability and the anti-interference ability of the reagent are further improved. The reagent disclosed by the invention is simple, convenient and rapid to operate, is suitable for automatic analysis, and is a lactic dehydrogenase and uric acid combined detection reagent which is more stable and strong in anti-interference capability.

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 application discloses a preparation method of a metalized chiral COF and application of the metalized chiral COF in electrochemical circular polarization light detection, and the preparation method of the metalized chiral COF comprises the following steps: taking 1,3,5-triformylphloroglucinol, trimethylaniline, a chiral inducer and 2,2'-bipyridine-5,5'-diamine as raw materials, and synthesizing a chiral COF through a solvothermal reaction; then, a coordination reaction is carried out with a metal salt in an alcohol solvent to obtain a metalized chiral COF material; the metalized chiral COF material is used as a photoanode material, spin polarization induced by circular polarization light (CPL) is coupled with a spin-selective oxygen evolution reaction (OER), and a nonlinear characteristic of OER reaction kinetics is used to amplify a micro-spin signal; the material has excellent photoelectric current anisotropy factor (g Iph ) and stability, and solves the problem of low sensitivity of an existing solid-state CPL detector.

The application discloses a method for photocatalytic synthesis of aniline compounds containing heptafluoroisopropyl substitution, which comprises the following steps: mixing o-methylaniline, 2-bromoheptafluoropropane and an iridium photocatalyst, adding an ultradry solvent, stirring and reacting the reaction mixture under a light source, and maintaining the reaction temperature at room temperature to obtain the target product, i.e. the aniline compound containing heptafluoroisopropyl substitution. The application adopts photocatalysis, does not need heating, has no solid waste problem, is more environmentally friendly compared with a traditional sodium hydrosulfite reduction reaction, and has a much higher photocatalytic reaction yield than the traditional reduction reaction, low catalyst consumption, high yield and good selectivity.

The invention discloses a high-stability anti-interference free fatty acid detection kit as well as a preparation method and application thereof, the kit comprises a reagent R1 and a reagent R2, the reagent R1 comprises a phosphate buffer solution, acetyl coenzyme A synthetase, coenzyme A, adenosine triphosphate, 4-aminoantipyrine and a cyclodextrin-metal organic framework nano stabilizer with the concentration of 5-20 mg / mL; and the reagent R2 is prepared from a Tris-HCl buffer solution, acetyl coenzyme A oxidase, peroxidase, N-ethyl-N-(3-sulfopropyl)-3-methylaniline sodium salt and a cyclodextrin-metal organic framework nano stabilizer with the concentration of 2 to 10mg / mL. Through the CD-MOF nano material with the specific aperture, triple breakthrough of improving the enzyme stability, enhancing the interference resistance of a complex sample and optimizing the detection sensitivity is synchronously realized.

The application discloses a kind of synthesis method of dasatinib intermediate in the field of organic synthesis, with 2-aminothiazole-4-carboxylic acid as raw material, first and tert-pivaloyl chloride in situ generates mixed anhydride, further and 2-chloro-6-methylaniline condensation reaction occurs after, the compound 2 obtained is not separated directly hydrolyzed to obtain high-purity 2-amino-N-(2-chloro-6-methylphenyl) thiazole-5-formamide.Due to the mixed anhydride formed by tert-pivaloyl chloride has greater steric hindrance, and the further reaction of corresponding amine is conducive to the regioselectivity, and by-product tert-pivalic acid can be easily removed by post-treatment, so as to solve the disadvantages existing in the prior art, the unit operation involved in the whole preparation process is simpler, and the product purity and yield are higher, with good application prospect.

The invention relates to a preparation method of medroxyprogesterone acetate. The preparation method of medroxyprogesterone acetate comprises the following steps: mixing 17alpha-hydroxyprogesterone with glacial acetic acid, acetic anhydride and a first catalyst for first reaction to prepare an intermediate 1; mixing the intermediate 1 with tetrahydrofuran, ethanol, triethyl orthoformate and a second catalyst to carry out a second reaction, then adding formaldehyde and N-methylaniline to carry out a third reaction, then adding hydrochloric acid and water to carry out a fourth reaction, and collecting a crude product of an intermediate 2; and preparing the medroxyprogesterone acetate through a series of refining steps. According to the preparation method, the dosage of the palladium-carbon catalyst is small, the cost can be obviously reduced, and the product is lower in impurity content and higher in purity.

The present application relates to a kind of methods for preparing high-purity 5-chloro-2-methylaniline, 1) chlorination: 2-nitrotoluene, ferric chloride, organic sulfide are added to reaction bottle, after reaction is completed, the system is heated to 105~110 ℃ and is degassed 2~5h, and 4-chloro-2-nitrotoluene crude product is obtained.2) Preliminary purification: the 4-chloro-2-nitrotoluene crude product obtained in 1) is heated to 50~60 ℃, slowly cooled to 30~40 ℃, there is a small amount of crystallization in the system, keep 1h, filter, filter cake is recycled and reused, and the filtrate is higher-purity 4-chloro-2-nitrotoluene.3) Reduction: 4-chloro-2-nitrotoluene, ethanol, Pt / C are added to autoclave, after gas replacement, heating to 40~50 ℃, and reaction 2~3h. After reaction is completed, the reaction liquid is dehydrated under reduced pressure, and the concentrated liquid is washed with water.4) Rectification purification.The advantages are high product yield, high purity, low cost, and small environmental pollution.

Polymorphs and crystalline forms of 2-fluoro-5-((5S,5aS,6S,9R)-1-fluoro-12-(((2R,7aS)-2-fluorotetrahydro-1H-pyrrolizine-7a(5H)-yl)methoxy)-5-methyl-5a,6,7,8,9,10-hexahydro-5H-4-oxa-3,10a,11,13,14-pentaza-6,9-methanonaphtho[1,8-ab]heptalen-2-yl)-3-methyl-4-(trifluoromethyl)aniline (compounds of chemical formula (I)), pharmaceutical compositions thereof, and methods of using them, for example, in the treatment of cancer are provided herein. A synthesis process for the preparation of a compound of formula (I) (i.e., 2-fluoro-5-((5S,5aS,6S,9R)-1-fluoro-12-(((2R,7aS)-2-fluorotetrahydro-1H-pyrrolizine-7a(5H)-yl)methoxy)-5-methyl-5a,6,7,8,9,10-hexahydro-5H-4-oxa-3,10a,11,13,14-pentaza-6,9-methanonaphtho[1,8-ab]heptalen-2-yl)-3-methyl-4-(trifluoromethyl)aniline) is also provided herein. Compounds useful for the synthesis thereof (e.g., compounds of formulas (A), (B), (By), and (H)) and a synthesis process relating thereto are also provided.

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 catalyst for aniline alkylation and a preparation method, and belongs to the technical field of catalysts. The preparation method of the catalyst comprises the following steps: roasting a catalyst carrier precursor, and adding desalted water into a roasted product to prepare slurry; preparing a mixed solution of copper salt, zinc salt and chromium salt; additionally preparing an alkali solution; adding a metal salt mixed solution and an alkaline solution into the slurry, carrying out a co-precipitation reaction, and then aging; repeatedly filtering and pulping the aged slurry to obtain a catalyst precipitation filter cake; and drying, forming and calcining to obtain the catalyst. The invention also discloses the catalyst for aniline alkylation, which is prepared by the method. The catalyst provided by the invention can realize concerted catalysis of aniline alkylation and methanol steam cracking in a single reactor, methanol and aniline are taken as raw materials, N-methylaniline is synthesized with high selectivity, high-purity hydrogen is co-produced, and no wastewater is discharged in the reaction process.