46 results about "Electrophilic substitution" patented technology

The invention relates to the field of macromolecular surfactants, and discloses an agricultural macromolecular surfactant and a preparation method thereof. The preparation method comprises the following steps: introducing a plurality of hydrophilic polyethylene glycol side chains into sodium lignin sulfonate molecules by adopting an electrophilic substitution reaction to prepare novel anionic sodium lignin sulfonate polyoxyethylene ether, introducing a tetramethyl piperidylamine monomer by virtue of a Mannich reaction to synthesize novel hindered amine grafted sodium lignin sulfonate polyoxyethylene ether, the stable agricultural polymer surfactant is prepared by mixing a cationic surfactant hexadecyl trimethyl ammonium bromide and the cationic surfactant hexadecyl trimethyl ammonium bromide, and the agricultural polymer surfactant has strong surface activity, dispersing performance and photolysis resistance.

The invention discloses a preparation method of polyetherketoneketone, polyetherketoneketone and application. The method comprises the following steps: (1) mixing raw materials at a first temperature, the raw materials comprising acyl chloride, a solvent, Lewis base, diphenyl ether and Lewis acid, carrying out heat preservation, heating to a second temperature, and carrying out a first reaction stage; (2) heating to a third temperature for reaction, and carrying out a second reaction stage; (3) adding a terminator into the reaction mixture in the step (2); the heating rate in the step (1) and the heating rate in the step (2) are respectively and independently 0.1-5 DEG C / min, the weight-average molecular weight of the polyetherketoneketone prepared by the method is 5000-200000, and the molecular weight distribution coefficient is 2.5-4.5. The polyetherketoneketone with relatively narrow molecular weight distribution is obtained through an electrophilic substitution path.

The invention discloses a preparation method of a hydroxyl-functionalized quaternary phosphonium salt polyion liquid super-crosslinked heterogeneous catalyst and an application of the catalyst in catalysis of a cycloaddition reaction of CO2 and epoxide. Trimethoxytriphenylphosphine and dibromo-p-xylene are firstly subjected to quaternary phosphating to form triphenylphosphine-based ionic liquid, and then the triphenylphosphine-based ionic liquid and biphenyl benzyl dichloride can be subjected to aromatic electrophilic substitution reaction in the presence of 1, 2-dichloroethane serving as a solvent and anhydrous aluminum chloride serving as a Lewis acid catalyst to realize cross-linking, so that the triphenylphosphine-based ionic liquid can be prepared. And methoxy can be removed to form hydroxyl, so that the hydroxyl-functionalized quaternary phosphonium salt polyion liquid super-crosslinked polymer is prepared in one step. The resulting heterogeneous catalyst effectively converts CO2 to cyclic carbonates under milder conditions (80 DEG C, 1 atm) in the absence of a soluble co-catalyst.

This invention belongs to the field of semiconductor packaging, and provides a photosensitive resin, its preparation method, and a photosensitive resin composition. The photosensitive resin is formed by an electrophilic substitution reaction of a phenolic prepolymer and an electrophilic reagent. The phenolic prepolymer is formed by a polycondensation reaction of monomer I (structure shown in Formula 1) and monomer II (structure shown in Formula 2), wherein m and n independently represent 1 or 2, and Ar is an aryl group with 6 to 18 carbon atoms. When this resin is applied to a photosensitive resin composition, the cured material formed by the composition possesses good etching resistance, mechanical properties, and high thermal stability.

The application relates to the field of high-molecular surfactants, and discloses an agricultural high-molecular surfactant and a preparation method thereof. The preparation method comprises the following steps: introducing multiple hydrophilic polyethylene glycol side chains into a sodium lignosulfonate molecule by using an electrophilic substitution reaction to prepare a novel anionic sodium lignosulfonate polyoxyethylene ether, introducing a tetramethylpiperidinamine monomer by using a Mannich reaction to synthesize a novel hindered amine grafted sodium lignosulfonate polyoxyethylene ether, mixing a cationic surfactant hexadecyl trimethyl ammonium bromide with the hindered amine grafted sodium lignosulfonate polyoxyethylene ether to obtain a stable agricultural high-molecular surfactant, and the agricultural high-molecular surfactant has strong surface activity, dispersing performance and photolysis resistance.

The invention discloses a method for synthesizing mesalazine and application of mesalazine. The method comprises the following steps: introducing p-nitrophenol, formic acid and a Cu-Co-coated MFI-NS molecular sieve catalyst into a continuous flow reaction zone, and sequentially carrying out electrophilic substitution and nitro hydrogenation cascade reaction at normal pressure and 50-70 DEG C; the catalyst has a micropore-mesopore stepped pore channel, and contains a Cu0 metal cluster and a framework Co < 2 + > acid site. And separating, acidifying and crystallizing the reaction liquid to obtain a finished product. According to the invention, the shape-selective selectivity and difunctional synergistic effect of the molecular sieve are utilized, high conversion rate (gt, 98%) and high selectivity (gt, 94%) under mild conditions are realized, the product purity is greater than or equal to 99.5%, and the Cu / Co residue meets the ICHQ3D standard. The catalyst can be recycled for 10 times or more, the yield is reduced by 5% or less, iron mud pollution of a traditional iron powder method and the metal leaching risk of a noble metal catalyst are thoroughly eliminated, and the method has the remarkable advantages of being environmentally friendly, efficient, low in cost, easy to industrially amplify and the like and is suitable for preparing the medicine for treating the inflammatory bowel disease.

The invention provides a production method of 4-10B-boric acid-L-phenylalanine with high boron atom utilization rate, which comprises the following steps: A, adding strong base and a Turbo Grignard reagent into a 4-halogenated-phenylalanine derivative for reaction, and then adding glycol ester borane for continuous reaction to obtain a 4-boryl-phenylalanine derivative; and B, carrying out acidic hydrolysis on the 4-boryl-phenylalanine derivative, so as to obtain the 4-10B-boric acid-L-phenylalanine. The boron element is introduced into phenylalanine molecules through halogen-metal exchange and electrophilic substitution reaction, wherein the reagent combination of the Turbo Grignard reagent and the glycol ester borane ensures the efficient proceeding of the boronylation process. The production method disclosed by the invention is mild in reaction condition and simple to operate, has high-level comprehensive yield and 10B boron atom utilization rate, and provides a new way for realizing low-cost commercial production of 10B-BPA.

The invention provides a preparation method of a diphosphine ligand and a hydroformylation reaction method, and relates to the technical field of catalysts. The preparation method is as shown in a reaction formula (A) or a reaction formula (B), under the action of first Lewis acid, a compound as shown in a formula (1) and a compound as shown in a formula (2.1) or a formula (2.2) are subjected to an electrophilic substitution reaction, the reacted material is extracted, concentrated and recrystallized, and the diphosphine ligand as shown in a formula (3.1) or a formula (3.2) is obtained; reaction formula (A); reaction formula (B); according to the preparation method of the diphosphine ligand, the technological process is simple, the reaction system is simplified, the use of flammable and explosive organic lithium reagents can be avoided, the safety is improved, and the high-purity diphosphine ligand can be obtained. The diphosphine ligand prepared by the invention can catalyze the enol hydroformylation reaction to be efficiently carried out, so that the enol conversion rate is not less than 99%, the product selectivity is not less than 95%, and the normal / isomeric ratio of the prepared aldehyde product is greater than 30.

The invention relates to an acyl transfer reagent and a preparation method of an amide compound, and belongs to the field of organic synthesis in organic chemistry. Polyfluoro-substituted aromatic hydrocarbon, acyl chloride and a sulfur transfer reagent are adopted as raw materials, polyfluoro aryl thioester is obtained through two continuous electrophilic substitution reactions, and then further application research proves that the compound is an efficient acyl transfer reagent and can be used for acylation reactions of various amines. The route and reaction conditions adopted in the method are green, environment-friendly, simple and mild, the raw materials are easy to obtain, the product selectivity is high, the variety is rich, and the method is expected to be further applied to industrial production.

The invention discloses a preparation method of a glassine. The preparation method comprises the following steps: a) preparing raw materials; step b) condensation reaction; c) reduction reaction; step d) electrophilic substitution reaction; step e) crystallization and purification: step a) raw material preparation. According to the present invention, the electrophilic substitution reaction can be performed under the mild condition without the extreme reaction conditions such as the high temperature or the high pressure, such that the reaction is easily controlled, and the monomer source used by the electrophilic substitution reaction is generally convenient compared with the other types of the organic reactions; the xylose subjected to the condensation reaction is beneficial to improving the permeability of the glassy pigment, so that the glassy pigment can be deeply permeated into the skin, the energy consumption and waste emission in the production process can be reduced, and meanwhile, the treatment is performed in a heating and pressurizing manner in the reaction process, so that incomplete reaction or by-product generation can be avoided, and the production cost is reduced. And the final crystallization purification can improve the purity of the product.

The application discloses a nitrite fluorescent probe and a preparation method and application thereof. + The reaction makes the spiro ring open, the conjugated system recovers, the fluorescence emission signal is enhanced, a fluorescence-on detection mode is realized, a boronic acid group is introduced in the probe design, a benzene ring is activated, electrophilic substitution reactivity is improved, the coordination of an amine group and a metal ion is eliminated, the anti-interference ability of the probe to the coordination of metal ions is improved, and rapid, high-selectivity and high-sensitivity detection of nitrite in a complex food matrix is realized. The application also discloses application of the fluorescent probe. The prepared fluorescent probe has the technical effects of good water solubility, high sensitivity, high specificity and strong anti-interference ability.

This invention discloses a method for preparing hyperbranched polyphenylene sulfide-modified nanomaterials. By modifying the ends of mesoporous nanomaterials with amino groups, and reacting the amino groups with acyl halides at low temperature, terminal halogen-modified mesoporous nanomaterials are obtained. Then, polyphenylene sulfide is grown on the surface of the mesoporous nanomaterials through an electrophilic substitution reaction. The resulting nanomaterials are in-situ polymerized with oligophenylene sulfide resin, which greatly enhances the compatibility between the nanomaterials and polyphenylene sulfide resin, while improving the corrosion resistance of thermoplastic resins and extending the service life of thermoplastic resin coatings in geothermal environments.

The invention discloses a 3, 3-bisindole dialkyl compound and a synthesis method thereof, and the synthesis method comprises the following steps: (1) putting indole and a derivative thereof, a palladium catalyst, a ligand, alkali, a solvent and 3-bromo-3, 3-difluoropropylene into a reaction bottle, and carrying out a heating reaction at 80-100 DEG C for 6-12 h; and (2) after the reaction is finished, cooling to room temperature, extracting, removing the solvent by rotary evaporation, then adding dichloromethane into a reaction flask, adding silica gel, uniformly stirring to obtain a powdery solid, and finally separating and purifying by using a chromatographic column to obtain the 3, 3-bisindole dialkyl compound. According to the 3, 3-bisindole dialkyl compound and the synthesis method thereof, the fluorine-containing olefin with strong electron-withdrawing capability and the C-3 site of indole are more easily subjected to electrophilic substitution, the method has higher reaction activity and a wide application range, the temperature required by the reaction is lower, the reaction time is shorter, the reaction yield is considerable, the highest reaction yield can reach 88%, and the method is suitable for industrial production. The method has positive significance on green chemical synthesis.

The application provides a synthesis method of m-nitro diphenylamine compounds, which comprises the following steps: carrying out an electrophilic substitution reaction on m-nitro halogenated benzene and aniline or halogenated benzene and m-nitro aniline under the condition of a sulfonic acid compound catalyst and an ionic liquid solvent to obtain the m-nitro diphenylamine compounds. The synthesis method of the m-nitro diphenylamine compounds is simple in method steps, stable in process and high in yield.

The invention belongs to the technical field of lithium ion battery diaphragms, and particularly relates to a preparation method and application of a modified polyphenyl ether (PPO)-based coated polyolefin diaphragm. The preparation method comprises the following steps: (1) bromination treatment: preparing brominated polyphenyl ether (BPPO), dissolving PPO in a chlorobenzene solution, adding bromosuccinimide to carry out electrophilic substitution reaction, and taking azodiisobutyronitrile as an initiator; (2) preparing a three-layer composite diaphragm: preparing a membrane casting solution by adopting a non-solvent phase inversion method, taking N-methyl pyrrolidone as a solvent and taking polyethylene glycol as a pore-forming agent, forming BPPO coatings on double surfaces of a PE diaphragm by a blade coating process, and curing by a water / ethanol double-component coagulating bath; and (3) carrying out surface functionalization treatment: carrying out in-situ amination reaction on 3-aminopropyltrihydroxysilane, and constructing a cross-linked structure in the BPPO coating. Compared with the prior art, the coating diaphragm provided by the invention takes the cross-linked brominated PPO material as the diaphragm coating layer for the first time, the stability of the material is enhanced through molecular design, the thermal shrinkage rate is remarkably improved compared with that of a PE base material, and meanwhile, the coating diaphragm has a flame-retardant characteristic.

The invention discloses a heavy metal chelating flocculant with double chelating groups as well as a preparation method and application of the heavy metal chelating flocculant. The preparation method comprises the following steps: firstly, carrying out nucleophilic addition reaction on polyethylene polyamine and carbon disulfide in the presence of alkali, introducing-CSS <-> into a non-terminal position of a polyethylene polyamine molecule, and then carrying out electrophilic substitution reaction on the polyethylene polyamine molecule and haloacetate under a strong alkaline condition to introduce acetic acid groups into two ends of the molecule, so that the molecule has two strong chelating groups, namely-CSS <-> and-N (CH2COO-) 2. The two chelating groups in the molecule can complement each other and have a synergistic effect, so that the chelating binding capacity and the flocculation precipitation performance of various heavy metal ions are remarkably improved, and efficient removal of various heavy metals is realized in one step. The defects that a common chelating agent is single in functional group, low in chelating capacity for some ions, not wide in applicable object range and the like are overcome; the preparation process is simple, mild in reaction condition, easy to operate and control, environment-friendly in technological process and easy to realize industrial production.

This invention relates to the field of acyclic or carbocyclic compounds and discloses a method for preparing 6-bromo-2,3-difluorotrifluorotoluene, comprising: dissolving 2,3-difluorotrifluorotoluene in a mixed solvent composed of a polar modifier containing a proton acceptor site and a nonpolar solvent; adding a polyether stabilizer and an iron-based catalyst; and dropwise adding liquid bromine to trigger a directional bromination reaction. The method utilizes the protonated ion-pair complex formed by the in-situ generation of hydrogen bromide and the polar modifier, which, in conjunction with the polyether stabilizer, constructs a sterically hindered shielding structure at positions 4 and 5 of the substrate molecule. This invention forces the electrophilic substitution pathway to be directed towards position 6 of the substrate molecule, overcoming the bottleneck of extremely low positioning accuracy in passivated aromatic ring systems, transforming disordered isomers into a single dominant isomer, thereby reducing separation energy consumption.

The application discloses a method for repairing chlorobenzene contaminated groundwater in-situ by using soluble Mn(III), and belongs to the technical field of environmental pollution repair, and comprises the following steps: construction of an in-situ injection system, preparation of a repair reagent, rapid removal of chlorobenzene, and continuous mineralization of degradation products. The soluble Mn(III) generated by a permanganate / bisulfite (PM / BS) process is selected as the repair reagent, the chlorobenzene pollutants are rapidly and efficiently degraded through an electrophilic substitution mechanism, the PM process is coupled, the continuous mineralization of intermediate products is realized, and the complete elimination of the chlorobenzene pollutants in the groundwater is achieved. The technical method is simple and practical, the process is green, the treatment effect is complete and not prone to rebound, the cost is relatively low, the method is beneficial to large-scale promotion, and the method has remarkable economic, environmental and social effects.

The invention provides a preparation method of octabromoS ether, and belongs to the technical field of flame-retardant materials. According to the preparation method, bisphenol S and allyl bromide are subjected to a carbon-oxygen coupling reaction under catalysis of a transition metal compound catalyst, bisphenol S diallyl ether and hydrogen bromide are obtained, hydrogen bromide can be recycled in a subsequent addition reaction, and the cost is saved; then hydrobromic acid and bisphenol S diallyl ether are subjected to an addition-electrophilic substitution reaction under catalytic oxidation of hydrogen peroxide to obtain octabromo-S ether, and high-toxicity bromine is not adopted; hydrogen peroxide is reduced into water in the reaction, so that the method is green and environment-friendly.

The invention discloses a biomass halogen-free phosphorus-free flame retardant, a durable flame-retardant modified silk fabric and a preparation method of the durable flame-retardant modified silk fabric, and belongs to the field of functional textiles. The preparation method of the flame retardant comprises the following steps: enabling tannic acid and terephthalaldehyde to react under a proper pH condition to form a prepolymer with a three-dimensional network structure, and arranging the prepolymer on the silk fabric. The core of the invention is to realize lasting immobilization of the flame retardant through a step-by-step covalent cross-linking strategy: firstly, an aldehyde group of terephthalaldehyde and a phenolic hydroxyl group of tannic acid are subjected to electrophilic substitution to form a methylene bridge, and a three-dimensional network is constructed; afterwards, in high-temperature finishing, surplus aldehyde groups in the network and amino groups on the surface of the silk fabric form C = N covalent bonds through Schiff base reaction. The flame retardant and the fibers are stably combined in a dual covalent cross-linking'structure anchoring 'mode, so that the flame-retardant efficiency and durability of the modified silk fabric are remarkably improved, and the defect that the traditional flame retardant is easy to dissolve and lose is overcome.

This invention discloses a method for preparing a high-power sodium-ion battery hard carbon anode material: N,N-dimethylformamide, phosphorus oxychloride, and lignin powder are mixed in an anhydrous closed stirring apparatus under an inert atmosphere, heated to 75-83°C and stirred, then filtered to obtain filter residue rich in imine organic compounds; then added to deionized water and stirred, filtered to obtain formylated lignin powder; the formylated lignin powder is then subjected to high-temperature carbonization under an inert atmosphere to obtain the high-power sodium-ion battery hard carbon anode material. This invention also discloses a sodium-ion battery containing this hard carbon anode material. This invention utilizes the aromatic compounds in lignin to carry out electrophilic substitution reactions, thereby increasing the reversible adsorption of Na on the surface of the hard carbon anode material. + Oxygen-containing groups and oxygen atoms, when doped, will increase the number of active adsorption sites in the material, increase the interlayer spacing, improve the rate performance of the material, and also increase the specific capacity of the material.

The application provides a coal-based hard carbon negative material, a preparation method thereof and a sodium ion battery negative electrode, and belongs to the technical field of sodium ion batteries. 3 The application breaks the original pi-pi conjugate stacking of aromatic clusters by using the sp Hybrid characteristics of the introduced sulfonic acid groups, breaks the original pi-pi conjugate stacking of aromatic clusters, thereby constructing a disordered microcrystalline structure rich in hybrid states at the molecular level, and effectively enlarging the interlayer spacing of the material after carbonization; meanwhile, the application uses concentrated sulfuric acid for electrophilic substitution sulfonation modification, can control the substitution position of the sulfonic acid group at the para position, realizes the directional regulation of the HOMO energy level of the molecule, and the para substitution product has the highest HOMO energy level and a lower energy band gap, can enhance the confinement effect on electrons, binds the electrons in the anode material, reduces the irreversible decomposition of sodium salt in the electrolyte, and induces the formation of a highly stable inorganic SEI film rich in fluorine species, realizes the synthesis of a high-performance hard carbon negative electrode material.

The present invention relates to: a sulfonic acid group-containing polymer having a novel structure; a cation exchange membrane; a manufacturing method thereof; and water electrolysis systems using same. More specifically, the present invention relates to: a polymer having a branched structure; and a cation exchange membrane and water electrolysis systems in which the polymer is used to promote a microphase-separated structure, wherein rather than developing a cation exchange material through conventional condensation polymerization in the presence of a basic catalyst, structural design is carried out using an electrophilic substitution reaction under strongly acidic conditions such that the main chain of the polymer does not contain any chemically weak bonds (e.g., ether bond), and various ion exchange functional groups can only be introduced at the side chain ends of the polymer.

The invention provides a deuterated dicarbazole compound and a preparation method thereof, and belongs to the field of organic photoelectric materials. The bicarbazole compound and the deuterated trifluoromethanesulfonic acid heavy water solution are mixed, the strong acidity of the deuterated trifluoromethanesulfonic acid is utilized to provide enough deuterium positive ions, the deuterated trifluoromethanesulfonic acid and aryl in the bicarbazole compound form an extremely unstable sigma-complex (aryl positive ions), the fracture strength of C-H is much smaller than that of C-D, and the stability of the compound is greatly improved. The deuterated dicarbazole compound has the advantages that one hydrogen atom is quickly lost to recover a stable aromatic system, so that the deuterated dicarbazole compound is obtained, only H-D electrophilic substitution is involved in the process, generation of other impurities is avoided, and the yield and the purity of the deuterated dicarbazole compound are improved; the yield of the deuterated dicarbazole compound is further improved by increasing the number of times of the deuteration reaction.

The invention discloses a synthetic method of high-purity p-methoxybenzoic acid. The synthetic method comprises six steps of catalyst activation, electrophilic substitution, quenching, hydrolysis, solvent recovery and purification and crystallization. Through aluminum trichloride-carbon tetrachloride complex pre-activation, low-temperature dropwise adding (0-5 DEG C and 5-10 DEG C), gradient temperature control quenching (less than or equal to 10 DEG C to 20-25 DEG C), 10-12% hydrochloric acid hydrolysis, normal pressure / reduced pressure distillation and methanol aqueous solution gradient crystallization, the product purity reaches 99.5%-99.8%, the yield is 91.5%-93.8%, the para-selectivity is greater than or equal to 98%, and the solvent recovery rate is 94.7%-96.6%. The method effectively reduces by-products, emulsification and impurities, reduces the cost through solvent recycling, and is suitable for industrial production of medicine and perfume intermediates.

The invention relates to the technical field of catalysis, in particular to a catalyst system for synthesizing butyraldehyde through hydroformylation and application of the catalyst system. The invention relates to a catalyst system for synthesizing butyraldehyde through hydroformylation. The catalyst system comprises a first ligand, a second ligand and a metal active component, the first ligand is a bidentate rigid phosphine ligand, and the second ligand is a monodentate auxiliary phosphine ligand; the preparation method of the first ligand comprises the following steps: 1) reacting o-bromotoluene, tert-butyl lithium and diphenyl phosphine chloride to obtain o-tert-butyl diphenyl phosphine; (2) carrying out electrophilic substitution reaction on o-tert-butyl diphenylphosphine and silver trifluoromethanesulfonate to introduce-CF3 groups to benzene ring para-positions; then, purification is carried out, and o-tert-butyl-p-trifluoromethyl diphenylphosphine is obtained; 3, tert-butyl-p-trifluoromethyl diphenylphosphine reacts with 1, 2-dibromoethane to generate a bidentate ligand, then recrystallization purification is conducted, and the first ligand is obtained.When the first ligand is applied to a reaction for synthesizing butyraldehyde through hydroformylation, the normal / isomeric ratio of the obtained product can reach 25.4-30: 1.

A method for preparing multi-component polymers through post-polymerization modification, used to functionalize polysulfonyl imidate polymer including a dispersing polymer reactant, an electrophilic substitution reagent and a catalyst in an organic dispersant; adding acid-binding agent to react at room temperature for 4-48 h; obtaining the precipitate when the reaction finished; washing and drying the precipitate to get the functionalized multi-component polymers.

The present application relates to a kind of organic-inorganic hybrid monolithic material containing bipyridine and preparation and CB [5] and CB [7] separation. Specifically, first using tetramethoxysilane and 3-chloropropyl trimethoxysilane as silane reagent, urea and polyethylene glycol-10000 as porogen, after hydrolysis reaction of silane reagent, copolymerization is carried out into the silica gel monolithic material with chlorine atom, then through electrophilic substitution reaction modification 4,4-bipyridine, obtain a kind of organic-inorganic hybrid monolithic material containing bipyridine. Using the difference between CB [5], CB [7] and host-guest interaction of bipyridine, the selective separation of CB [5] and CB [7] is realized. The method used in the present application process is simple, organic solvent is used less, green and environmental protection, can be applied to large-scale preparation high-purity CB [5] and CB [7], with good commercialization prospect.

The invention relates to a method for directionally preparing 2, 6-dichlorotoluene, and belongs to the technical field of dichlorotoluene preparation. The catalyst is aluminum trichloride and ferric trichloride composite metal salt ionic liquid, and has higher stability and low hygroscopicity compared with chloroaluminate ionic liquid. The composite ionic liquid reacts with chlorine to generate an aluminum trichloride-based chloride positive ion active intermediate B and an ionic liquid A, the intermediate B and o-chlorotoluene are subjected to electrophilic substitution to generate 2, 6-dichlorotoluene and release aluminum trichloride, and the ionic liquid A and aluminum trichloride form a composite metal salt ionic liquid to complete catalytic circulation. After the composite metal salt ionic liquid is applied to chlorine chlorination with o-chlorotoluene as a raw material, the proportion of 2, 6-dichlorotoluene in a mixed dichlorotoluene product is effectively increased, the content of 2, 6-dichlorotoluene reaches 37% at most, and the catalyst can be repeatedly used.

The invention discloses a near-infrared two-region fluorescent dye, which takes squaric acid dye as a framework, takes 4-methylene phenylboronic acid ester as a substituent group, and can form a stable J-aggregate without carrier coating. The synthesis method comprises the following steps: carrying out nucleophilic addition reaction on diethyl squarate and malononitrile under the catalytic action of weak base triethylamine to obtain a first intermediate product; carrying out electrophilic substitution reaction on the 4-methylquinoline and the 4-bromomethylphenylboronic acid pinacol ester to obtain a second intermediate product; and carrying out nucleophilic addition reaction on the two intermediate products to obtain the near-infrared two-region fluorescent dye. Compared with the traditional fluorescent dye with J-aggregation property, the J-aggregate constructed by the fluorescent dye disclosed by the invention has the remarkable advantage of long absorption / emission wavelength, the maximum emission peak red shift reaches about 1345 nm, the stable J-aggregate can be formed without carrier coating, and the J-aggregate has good biological safety and can be used for preparing the fluorescent dye with the J-aggregation property. The fluorescent probe can be applied to in-vivo angiography, tumor imaging, surgical navigation and the like through fluorescence imaging.