557 results about "Phosgene" patented technology

The invention belongs to the technical field of catalytic science, and relates to a preparation method of isocyanate catalyzed by a photoinitiator. The preparation method comprises the following steps: mixing an organic amine compound with chloroform, adding a photoinitiator 2959, carrying out irradiation reaction under ultraviolet light, and carrying out distillation or filtration to remove a solvent and byproducts so as to obtain isocyanate. According to the preparation method of the isocyanate provided by the invention, the oxidation of the chloroform compound on the organic amine is realized under a mild condition through the participation of the photoinitiator 2959, so that the isocyanate is generated. Compared with a traditional phosgene method, the method is safer and more environmentally friendly, reaction conditions are simple and easy to control, and the method has good industrial application potential.

Provided herein is a process for preparing compound A comprising (a) admixing 2-isopropyl-4-methylpyridin-3-amine (Compound B), or a salt thereof, a first base, and a reactive compound comprising phosgene or a phosgene equivalent in an organic solvent to form 3-isocyanato-2-isopropyl-4-methylpyridine (Compound C); (b) admixing Compound C and 2,6-dichloro-5-fluoronicotinamide (Compound D) to form 2,6-dichloro-5-fluoro-N-((2-isopropyl-4-methylpyridin-3-yl)carbamoyl)nicotinamide (Compound E); and (c) admixing Compound E and a second base to form a product mixture comprising Compound A and the second base. Also provided herein is a process for synthesizing AMG 510 comprising using Compound A prepared according to the disclosed processes

The invention relates to the technical field of isocyanate reaction, and discloses a reaction device for preparing o-tolyl isocyanate and a reaction method thereof.The reaction device comprises a reaction box, a cleaning and stirring mechanism is arranged in the reaction box and used for stirring and cleaning crystals adsorbed on the inner wall, an intermittent conveying mechanism is arranged on one side of the cleaning and stirring mechanism, and the intermittent conveying mechanism is arranged on the other side of the cleaning and stirring mechanism. The phosgene intermittent conveying device is provided with a clean stirring mechanism for intermittently conveying phosgene, the clean stirring mechanism is provided with a pressing discharging mechanism for pushing isocyanate to be rapidly discharged, it is guaranteed that reactants are evenly distributed in the whole reaction mixture through stirring, the local concentration is prevented from being too high or too low, and therefore the overall reaction efficiency and the product quality are improved; according to the reaction device, crystals can be shoveled down from the wall surface during stirring, the service life of the reaction device is prolonged, meanwhile, communication of the exhaust pipe is intermittently cut off, a communication hole in one side of the intermittent rotary table is communicated with the exhaust pipe, and the concentration of reactants in a reaction mixture can be adjusted by intermittently cutting off conveying of phosgene, so that the reaction rate is controlled.

The utility model relates to the technical field of stop valves, in particular to a corrugated pipe stop valve special for phosgene, which comprises a valve body, a fixing piece is fixed on the upper surface of the valve body, a connecting flange is fixed at the upper end of the fixing piece through a bolt, and two baffles are symmetrically fixed in the valve body. The left sides of the two baffles are both connected with movable gaskets, two movable plates are fixed to the left sides of the movable gaskets, guide rods fixed to the valve body penetrate through the interiors of the two movable plates, and the outer surfaces of the guide rods are sleeved with springs connected with the movable plates in an abutting mode. The tail end of the spring is connected with a limiting block in an abutting mode, wherein the limiting block and the guide rod are fixed. According to the utility model, through the arrangement of the baffle plate, when a medium suddenly enters the valve body, the movable gasket is pushed to move, the movable plate is driven to move, and the movable plate pushes the spring to compress, so that the impact force of the medium is absorbed, the impact force of the medium on the valve core is reduced, the service life of the valve core is prolonged, and the practicability is improved.

The invention relates to a preparation method and a preparation device of isocyanate, and the preparation method comprises the following steps: carrying out cold reaction on a phosgene solution and an amine solution in a cold reactor to obtain an intermediate mixed solution; separating the intermediate mixed solution by adopting a cyclone, obtaining a carbamoyl chloride mixed solution from an underflow port of the cyclone, and obtaining an amine hydrochloride mixed solution from an overflow port of the cyclone; the carbamyl chloride mixed solution enters a first thermal reactor for thermal reaction to obtain a first reaction product, and the amine hydrochloride mixed solution enters a second thermal reactor for thermal reaction to obtain a second reaction product; mixing the first reaction product and the second reaction product in a staying reactor to obtain an isocyanate reaction solution; and carrying out post-treatment on the isocyanate reaction liquid to obtain the isocyanate. The method can reduce the generation amount of urea by-products, further inhibits the generation of other subsequent by-products, reduces the chromaticity of the product, and improves the quality of isocyanate.

The invention discloses a preparation method of carbonyl fluoride, which comprises the following steps: with hexafluoropropylene and oxygen as raw materials, introducing gas into a reactor filled with a catalyst for reaction at high temperature; the catalyst is one of palladium oxide, ruthenium oxide, platinum oxide and molybdenum oxide. According to the scheme, the cost is low, the raw material utilization rate is high, and compared with other carbonyl fluoride synthesis methods, the reaction does not involve phosgene, fluorine and other dangerous chemicals, and reaction by-products are few. In addition, according to the method, the toxicity of raw materials is small, hexafluoropropylene can be completely reacted under the condition of excessive oxygen, the reaction process is environment-friendly and simple, and basically no three wastes are generated. According to the method, hexafluoropropylene and oxygen are adopted as raw materials which are common chemical raw materials and are cheap and easy to obtain, and the method is simple in reaction process, mild in reaction, easy to operate and suitable for industrial production.

The invention provides a method for preparing isocyanate. By adopting the method for preparing the isocyanate, the cost can be reduced. The method comprises the following steps: (1) carrying out cold phosgenation reaction on an amine compound, a solvent stream I and a phosgene solution to obtain a first mixed solution; (2) feeding the first mixed solution into a thermal reactor, and heating to carry out a thermal phosgenation reaction; (3) removing hydrogen chloride and phosgene from the second mixed solution to obtain a third mixed solution and a second gas mixture containing hydrogen chloride and phosgene; washing and absorbing the first gas mixture and the second gas mixture with a solvent to obtain a phosgene solution; feeding the phosgene solution into the cold reactor in the step (1); (4) carrying out solvent removal treatment on the third mixed solution to obtain an isocyanate crude product; meanwhile, the method is controlled to be carried out under the conditions that A1 is equal to 5-55 and A2 is equal to-15-50.

Disclosed is a preparation method for a 1,5-dihydro-2,4-benzodiazepine-3-one derivative. According to the preparation method, required raw materials are cheap and easily available; the use of a flammable and explosive reagent namely borane, a difficult-to-handle and highly-toxic reagent namely triphosgene, and a precious metal namely palladium is avoided; the operation is simple and convenient, production costs are reduced; and the preparation method is more suitable for industrial preparation and use, and has higher yield than that of the prior art. Additionally, further disclosed are an intermediate as shown in formula III or a salt thereof for preparing the derivative, and a preparation method for the intermediate or salt.

The invention provides a preparation method of polycarbonate, which comprises the following steps: firstly, obtaining a polycarbonate oligomer obtained by reacting bisphenol or polyphenol with phosgene, adding an end-capping reagent, continuing to react until the content of acyl chloride is specific, and adding a catalyst until the reaction end point. Wherein when the catalyst is controlled to be added, the reaction system meets the following conditions: (1) 0.1 < = [-COCl]: [-OH] < = N [-COCl]: N [-OH]; and (2) the ratio of the input molar weight of the catalyst to the molar weight of the terminal group acyl chloride in the system is 1: 5-5: 1 when the catalyst is added. By adopting the method, the polycarbonate with excellent quality can be prepared.

The present application provides a method for purifying an amine salt (e.g., pentanediamine carbonate). According to the method, the amine salt (e.g., pentanediamine carbonate) is heated, flash-evaporated, and sublimed to obtain a purified gaseous amine salt (e.g., pentanediamine carbonate) which is directly used for further preparation of isocyanate (e.g., pentamethylenediisocyanate), and there is no need to use an alkaline substance to treat the amine salt to form a free-state amine for further preparation of isocyanate (e.g., pentamethylenediisocyanate). The present application further provides a method for preparing isocyanate (e.g., pentamethylenediisocyanate) from an amine salt (e.g., a pentanediamine salt) and phosgene. The present application further provides a device for implementing the method of the present application.

The invention provides a preparation method of a chlorantraniliprole key intermediate 2-amino-5-cyano-N, 3-dimethyl benzamide, which comprises the following steps: taking cheap and easily available o-methylaniline as a raw material, acylating an aniline substrate through Boc anhydride, carrying out ortho-lithiation on n-butyllithium, introducing carbon dioxide gas, and carrying out acid hydrolysis to obtain 2-amino-3-methyl benzoic acid, thereby obtaining the chlorantraniliprole key intermediate 2-amino-5-cyano-N, 3-dimethyl benzamide. The preparation method comprises the following steps: firstly, preparing an isatoic anhydride intermediate, then carrying out triphosgene ring closing to obtain an isatoic anhydride intermediate, carrying out bromine para-position halogenation, carrying out cuprous cyanide high-temperature Rosenmn-von Braun reaction, and finally carrying out methylamine ring opening to obtain the target product 2-amino-5-cyano-N, 3-dimethylbenzamide, and although the route is long, the yield is high, the continuity is good, few industrial three wastes are generated, and the cost is lower, so that the preparation method has great industrial production value.

The invention discloses a continuous preparation method of lauroyl chloride, which comprises the following steps: heating and melting lauric acid to obtain lauric acid melt; the method comprises the following steps: preparing an overflow diode reactor, continuously introducing phosgene and lauric acid melt into a first tubular reactor, reacting at 50-100 DEG C to obtain a photochemical reaction solution, continuously overflowing the photochemical reaction solution into a second tubular reactor, continuously reacting the unfinished reaction solution, and driving light by nitrogen to obtain lauroyl chloride. The continuous preparation method disclosed by the invention has the advantages of simple process, low online liquid carrying amount, convenience in operation, low cost and the like, and the obtained product is low in chromaticity, high in purity, few in impurities, suitable for industrial production and wide in application prospect.

The invention relates to the technical field of chemical recovery, and particularly discloses a carbon tetrachloride removal system and process, the system comprises a washing tower and a carbon tetrachloride removal assembly, the washing tower is used for introducing a solvent and a phosgene material; the tower top of the washing tower is used for outputting treated substances; a tower kettle of the washing tower is communicated with the carbon tetrachloride removal assembly, and the carbon tetrachloride removal assembly is used for removing carbon tetrachloride in materials from the washing tower. The solvent is introduced into the washing tower to wash the phosgene material, and after the solvent is introduced, the washing tower is not pure phosgene equipment, so that the safety performance is improved; and compared with the prior art that carbon tetrachloride is removed by utilizing a phosgene rectifying tower and a solvent refining tower, the combination of the washing tower and the carbon tetrachloride removal assembly is beneficial to reducing the energy consumption.

The invention provides a method for preparing toluene diisocynate through a phosgene method, and belongs to the technical field of toluene diisocynate preparation. According to the method, liquid phosgene is atomized into atomized phosgene through a high-pressure spraying device, the atomized phosgene is in countercurrent contact with a toluenediamine solution sprayed into a phosgenation reactor, the contact area of the atomized phosgene and the toluenediamine solution is increased, and the phosgenation reaction process is accelerated. In addition, due to the arrangement of the liquid homogenizer, the contact area between the atomized phosgene and the toluenediamine solution is increased, the reaction rate between the atomized phosgene and the toluenediamine solution is increased, and side reactions are reduced. Meanwhile, the phosgene participates in the phosgenation reaction in the form of mist droplets and is not dissolved in the solvent, so that the use of the solvent is greatly reduced, the concentration of the phosgene in the phosgenation reactor is improved, and side reactions are reduced. The liquid phosgene is subjected to high-pressure spraying treatment, so that the use of a solvent is saved, and subsequent solvent separation is facilitated. After the decomposition reaction is finished, hydrogen chloride gas and unreacted phosgene are separated in a freezing mode, phosgene recovery is achieved, and the recovery mode is simple.

The invention relates to a device for producing isocyanate by a light solvent method and a production method thereof, the device comprises a pre-fractionating tower and a main tower, the tower top of the pre-fractionating tower is communicated with the tower top of the main tower, and the tower kettle of the pre-fractionating tower is communicated with the tower kettle of the main tower; the method comprises the following steps: directly conveying an isocyanate photochemical reaction material prepared by a light solvent method into a pre-fractionating tower for primary separation, extracting phosgene and a solvent from the top of the pre-fractionating tower, and directly feeding the phosgene and the solvent into the top of a main tower; a solvent and isocyanate are extracted from a tower kettle of the pre-fractionating tower and then directly enter a tower kettle of the main tower, phosgene is separated from the tower top of the main tower, a liquid-phase solvent is extracted from a side line of the main tower, and an isocyanate crude product separated from the tower kettle of the main tower enters the next process; a phosgene removal tower for removing phosgene and a solvent in a photochemical reaction material and a first desolventizing tower are combined into a complex tower. Therefore, the process flow is optimized, the energy efficiency is improved, and the load and energy consumption for separating and purifying the isocyanate product are reduced.

The invention provides a preparation method of polyisocyanate. The preparation method comprises the following steps: S1, feeding a polyamine solution and a phosgene solution into a first reactor, and carrying out phosgenation reaction to obtain a first reactant flow; s2, the first reactor outlet material flow is sent to a second reactor to be continuously subjected to phosgenation reaction, and a second reactant flow is obtained; s3, conveying an outlet material flow of the second reactor to a third reactor for further phosgenation reaction to obtain a third reactant flow; S4, carrying out phosgene removal and HCl steam stripping treatment on the outlet material flow of the third reactor to obtain a fourth reactant flow; and S5, carrying out desolventizing treatment on the fourth reactant flow to obtain a crude polyisocyanate product. According to the preparation method, the reaction yield of amine and phosgene can be increased, the NCO content of the product is further increased, and the application performance of the product is improved.

The invention belongs to the technical field of fine chemical synthesis, and particularly relates to a device and a method for continuously preparing 1, 5-pentamethylene diisocyanate through thermal cracking. The method comprises the following steps: mixing and preheating a 1, 5-pentamethylene dicarbamate compound and bismuth neodecanoate, pumping the mixture into a reaction kettle filled with tetraethylene glycol dimethyl ether, carrying out a thermal cracking reaction, carrying out primary purification on the obtained reaction liquid, and continuously carrying out secondary purification to obtain the 1, 5-pentamethylene diisocyanate. According to the device and method for continuously preparing 1, 5-pentamethylene diisocyanate through thermal cracking, a non-phosgene method is adopted in the preparation process, the device and method are environmentally friendly, small in potential safety hazard, mild in reaction condition and simple and convenient in technology, the yield of 1, 5-pentamethylene diisocyanate reaches 80% or above, and the purity reaches 99%.

The present invention relates to a process for preparing 2, 4-di substituted thiophene-3- sulfonyl isocyanate compound of Formula (I), by reacting with the compound of Formula (II) with phosgene in the presence of a catalyst, and a mixture of a non-polar solvent and an organosulfur co-solvent, and optionally in the presence of a base.

The invention provides aliphatic acyl chloride and a purification method thereof. The purification method comprises the following steps: S1, introducing a crude product mixed solution which is obtained by reacting aliphatic carboxylic acid with phosgene and has the temperature of 50-100 DEG C into a gas driving tower at the flow rate of Q1, carrying out first purification, and extracting a first purified solution from the tower bottom of the gas driving tower; s2, the first purified liquid is introduced into a light component removal tower at the flow rate of Q2 for secondary purification, light component impurities are extracted from the tower top, and a second purified liquid is extracted from the tower bottom at the flow rate of Q3; s3, introducing the second purified liquid into a rectifying tower at the flow rate of Q4 for third purification, extracting a third purified liquid at the flow rate of Q5 from the tower top, and extracting heavy component impurities from the tower bottom; and S4, carrying out carbon adsorption treatment on the third purified liquid to obtain aliphatic acyl chloride. According to the method, residual phosgene, hydrogen chloride, amide compounds and light and heavy component impurities in the aliphatic acyl chloride crude product are effectively removed, and the purity of the aliphatic acyl chloride product is remarkably improved.

The present invention relates to a process for preparing polycarbonates from at least one dihydroxydiarylalkane, phosgene, at least one catalyst and at least one chain terminator by the phase interface process, wherein the process enables a reduced phosgene excess with a given energy input for dispersing the aqueous and organic phases. In addition, the process provides polycarbonates with a low oligomer fraction and a low di-chain terminator carbonate fraction.

The application discloses a continuous synthesis method of an amicarbazone intermediate 5-isopropyl-1,3,4-oxadiazole-2(3H)-ketone. The method comprises two continuous processes of hydrazinolysis and phosgenation: continuously feeding a mixture of isobutyric acid and a solvent, a mixture of hydrazine hydrate and a catalyst into a hydrazinolysis continuous reactor respectively, carrying out a warming reflux dehydration reaction, and obtaining an isobutyryl hydrazine solution shown in formula I; continuously feeding the isobutyryl hydrazine solution and phosgene into a phosgenation continuous reactor, carrying out a phosgenation reaction, and after distillation and desolventizing treatment of a reaction solution, obtaining 5-isopropyl-1,3,4-oxadiazole-2(3H)-ketone shown in formula II. The application has the advantages of simple reaction flow, high product yield, and significant production efficiency improvement, and is suitable for industrial large-scale production.

The present application relates to a kind of equipment and method for preparing hexamethylene diisocyanate by hexamethylene diaminoformate intermediate pyrolysis, the present application uses continuous pyrolysis reaction device, HDI can be prepared in high-boiling solvent, can completely replace the existing phosgene and phosgene derivative method for preparing HDI, solve the safety and pollution problem of phosgene method;Compared with low-boiling solvent process, the present application can greatly reduce energy consumption in product separation stage, and the energy consumption required for separating solvent in high-boiling solvent method is 1 / 10 of low-boiling solvent process, it is a green environmental protection energy-saving process;The present application uses non-toxic high-boiling solvent, compared with low-boiling solvent method, production safety is guaranteed;Compared with ordinary high-boiling solvent, the present application can avoid multiple contact between isocyanate and alcohol, and the yield of HDI can be further improved;The process flow of the present application is simple, and the operating condition is mild, it is a process that can be rapidly industrialized.

The invention discloses an antibacterial sleep-aiding latex pillow and a preparation method thereof, and relates to the technical field of latex. Silicon dioxide is preliminarily modified through 4-trimethoxysilylbutyraldehyde, m-phenylenediamine-sodium sulfonate and triphosgene, the antibacterial and anti-dust effects can be achieved, then natural silk fibroin and collagen are used for further modification, performance is improved, meanwhile, the modified silicon dioxide can form a particle layer on the surface of natural latex, and the antibacterial and anti-dust effects are achieved. Modified silicon dioxide is used as a nucleating agent, and an interpenetrating network structure is formed through supercritical foaming, vulcanization, deblocking and crosslinking of the modified silicon dioxide and the nucleating agent, so that the mechanical property of the latex pillow is improved; according to the invention, after foaming, aromatic particles are doped, the sleep-aiding essential oil composition is fixedly loaded by using graphene aerogel microspheres, and cyclodextrin is used for encapsulation, so that the aromatic particles can release essential oil only when in use.

The present invention relates to a method for preparing a diphenylmethane-based diisocyanate and polyisocyanate. The method comprises the following steps: S1. performing a phosgenation reaction on a diphenylmethane-based diamine and polyamine and phosgene in a solvent to obtain a first mixed solution; S2. performing phosgene removal treatment on the first mixed solution to obtain a second mixed solution; S3. performing stripping treatment on the second mixed solution by using HCl gas to obtain a third mixed solution; and S4. performing solvent removal treatment on the third mixed solution to obtain a crude diphenylmethane-based diisocyanate and polyisocyanate product. In the method for preparing a diphenylmethane-based diisocyanate and polyisocyanate as provided by an embodiment of the present invention, by optimizing process parameters of the stripping treatment step, a diphenylmethane-based diisocyanate and polyisocyanate product having a light color can be prepared.

The invention relates to a preparation method of a centralite I. The preparation method comprises the following steps: 1) adding N-ethylaniline into an alkaline aqueous solution, and mixing to obtain an N-ethylaniline mixed solution; 2) adding bis (trichloromethyl) carbonic acid into the N-ethylaniline mixed solution, and stirring for reaction; in the reaction process, the feeding reaction temperature is maintained to be lower than 110 DEG C by controlling the adding rate of the bis (trichloromethyl) carbonic acid, and a reaction product is obtained; and 3) carrying out solid-liquid separation on the reaction product to obtain the centralite I. Solid triphosgene is used as a raw material, the centralite I is prepared by a one-pot method, and the preparation process is stable. In the whole reaction process, the whole preparation process is safe and stable, and pollution is small.

The present application relates to a method for preparing an isocyanate. Specifically, in the method of the present application, phosgene (especially liquid phosgene) is used as a quench medium to prepare isocyanate.

The application relates to the technical field of organic synthesis, and discloses a synthesis method of benzthiazuron, which comprises the following steps: step 1, addition reaction of alpha-methyl styrene and hydrogen chloride gas, and degassing to obtain a first reaction liquid; step 2, substitution reaction of the first reaction liquid and cyanate in the presence of a zinc chloride catalyst, and filtration to obtain a second reaction liquid containing isocyanate; and step 3, construction of an inorganic salt aqueous solution system with a density of 1.05-1.10 g / ml and a pH of 9-10, dropwise addition of the second reaction liquid into the system for condensation reaction with o-chlorobenzylamine, and post-treatment and refinement to obtain a target product. The non-phosgene route of chloro-isocyanate substitution is adopted, and the use of the toxic phosgene is completely avoided; the salting-out effect and interface control generated by the specific high-density salt solution effectively inhibit the isocyanate hydrolysis side reaction, and the reaction yield and product purity are obviously improved.

The invention discloses a synthetic carbamate compound based on 3-substituted dioxazolone as well as a preparation method and application of the synthetic carbamate compound, and belongs to the technical field of organic synthesis. The synthesis method comprises the following steps: (1) preparing 3-substituted dioxazolone from hydroximic acid with different substituent groups and phosgene under an ice bath condition; and (2) reacting the 3-substituted dioxazolone obtained in the step (1) with different phenols (alcohols) under an alkaline condition to obtain corresponding carbamate compounds. According to the method, the yield of carbamate is further improved by adjusting the conditions of alkali, equivalent weight, temperature and the like; the preparation method provided by the invention is novel and has the advantages of mild reaction conditions, few generated impurities, high yield, high safety, convenience in operation and the like; and the compound shows good cholinesterase activity in activity screening, and can be used in insecticides or pesticides.

The present invention relates to a method for using an optionally alkoxylated nitrogen-containing polymer in the capture of carbon dioxide, said optionally alkoxylated nitrogen-containing polymer comprising the following steps: a) a step of reacting (i) a di- or oligoamine (A) with (ii) a crosslinking compound (BC) to provide a nitrogen-containing polymer (NP), wherein the crosslinking compound (BC) is (I) phosgene; or (II) comprises at least two amine-reactive groups (ARG), the crosslinking compound (BC) being capable of binding to the amine groups of at least two di- or oligoamine (A) molecules, the nitrogen-containing polymer (NP) comprising the molecular components of the crosslinking compound (BC) that bind to at least two molecular components of the di- or oligoamine (A), the proportion of the crosslinking compound (BC) molecules bound to at least two di- or oligoamine (A) molecules being the crosslinking factor (BF) of the nitrogen-containing polymer (NP), the crosslinking factor (BF) exceeding 50%, the sum of the primary and secondary amine groups of the nitrogen-containing polymer (NP) being at least 600 mg KOH / g, the number average molecular weight (Mn) of the nitrogen-containing polymer (NP) exceeding 600 g / mol, and b) a step of reacting the nitrogen-containing polymer (NP) with an alkylene oxide (AO), wherein the molar ratio of the alkylene oxide (AO) to the NH functionality of the nitrogen-containing polymer (NP) is 0.25 or less, obtainable by a method comprising. The present invention further relates to a method for capturing carbon dioxide from a gas mixture using an optionally alkoxylated nitrogen-containing polymer.

The invention provides a continuous synthesis system and method of 2-chloro-5-methylpyridine, the system comprises a tower reactor, a clinker kettle, a condenser, a first flash tank, a spray absorption tower, a second flash tank and a circulating pump, the synthesis method comprises the following steps: phosgene and an intermediate solution enter the tower reactor for reaction from bottom to top, after discharging, introducing into a clinker kettle for reaction, discharging reaction tail gas out of a system after condensation, after a certain retention time, discharging reaction synthetic liquid, introducing into a first flash tank for gas-liquid separation, introducing a gas-phase material into a spray absorption tower, discharging after absorption treatment, introducing a liquid-phase material into a second flash tank for secondary gas-liquid separation, and discharging after secondary gas-liquid separation; a gas-phase material obtained after secondary gas-liquid separation enters a clinker kettle, and a liquid-phase material is subjected to a post-treatment step to obtain a 2-chloro-5-methylpyridine product. By adopting the synthesis system and the synthesis method, the yield of the 2-chloro-5-methylpyridine is high, and the discharge of a large amount of wastewater with complex components is reduced.