392results about How to "Suitable for scale-up production" patented technology

The invention relates to a preparation method of a nitrogen and phosphorus containing flame retardant agent, the nitrogen and phosphorus containing flame agent and application thereof. The preparation method comprises the following steps of: carrying out condensation reaction on phenylene diamine and aromatic aldehyde, then carrying out addition reaction with DOPO (9, 10-Dihydro-9-oxa-10-phosphaphenanthrene 10-oxide) to obtain solid nitrogen and phosphorus containing flame retardant agent molecules. The preparation method has the advantages of easiness in control, good repeatability, high yield and suitability for expanded production. The obtained flame retardant agent molecules have amino groups and phenolic hydroxyl active groups and can further react with matters containing expoxy group functional groups. The flame retardant agent molecules contain nitrogen and phosphorus elements and have good expansion char forming characteristic and very good flame retardant effect in the burning process; when the flame retardant agent molecules resist the flaming of the epoxy resin, the flame retardant agent molecules can further undergo cross-linking reaction with resin, thereby increasing the glass transition temperature, the bonding strength, the mechanical property and the like of the resin; meanwhile, the flame retardant agent molecules have good flame retardant property; the limiting oxygen index of the flame retardant agent molecules is substantially increased; and the vertical burning grade of the flame retardant agent molecules reaches a UL-94V-0 grade.

The invention provides an elagolix synthesis method. The elagolix synthesis method comprises enabling a compound 5 and a compound 10 to participate in a condensation reaction to finish N-alkylation reaction to obtain a compound 11, and then implementing alkaline hydrolysis to obtain elagolix 12. The invention further discloses two synthesis methods of the compound 5: the method I comprises enabling a 5-bromine-6-methylpyrimidine-2,4(1H,3H)-diketone compound 1 and a 2-(brooethyl)-1-fluorin-3-(trifluoromethyl) benzene compound 2 to have a condensation reaction to obtain an intermediate 3, and then having a coupling reaction; the method II comprises enabling 1-halide-3-fluorin-2-anisole and acetoacetate 7 to have a coupling reaction to obtain a compound 8, and then having a condensation cyclization reaction with a compound 9; the improvements greatly shorten the route steps, the route efficiency is improved, the use of a noble metal catalyst is avoided, and the process cost is greatly lowered. The operation of the route is simple, the total yield is high, the purity of an obtained product is also relatively high, and the method is suitable for the enlarged production.

The invention discloses a method for synthesizing enantiomorphous pure symmetric trans-dialkyl cyclohexylamine, belonging to the field of chemistry. The method comprises the following steps of: carrying out an airtight or reflux reaction on cyclohexene oxide and an aqueous solution of alkylamine for reacting at 80-120 DEG C for 1.5-5h to obtain 2-alkyl-amino cyclohexanol, dropwise adding DEAD (Diethyl Azodicarboxylate) or DIAD (Diisopropyl Azodicarboxylate) to triphenylphosphine, 2-alkyl-amino cyclohexanol and a solvent under an ice bath for reacting for 5-20h at room temperature to obtain N-alkyl-7-azabicyclo[4, 1, 0]heptane, adding a catalyst to the N-alkyl-7-azabicyclo[4, 1, 0]heptane and the aqueous solution of alkylamine at 100-120 DEG C to carry out the airtight or reflux reaction to obtain trans-N,N'-dialkyl-1,2 cyclohexanamine, dissolving the trans-N,N'-dialkyl-1,2 cyclohexanamine in an alcoholic solvent, and adding a tartaric acid type resolving agent with the equivalent weight of 0.5 to the alcoholic solvent to resolve so as to obtain the enantiomorphous pure symmetric trans-dialkyl cyclohexylamine.

The invention relates to a 9,10-dihydro-9-oxa-10-phosphenanthrene-10-oxide (DOPO) group phosphorus-nitrogen flame retardant and a preparation method of the DOPO group phosphorus-nitrogen flame retardant. According to the preparation method, 4,4'-diaminodiphenyl and aromatic aldehyde undergo condensation reaction to obtain an imine intermediate product, and the imine intermediate product and DOPO undergo addition reaction to obtain the solid flame retardant. The preparation method is easy to control, good in repeatability, high in yield and suitable for large-scale production. The molecule of the flame retardant contains two flame retarding elements including phosphorus and nitrogen, and thus the flame retardant has good flame retarding effect and coal forming performance. Due to the fact that the molecules of the flame retardant have reactive hydrogen atoms of different numbers, the flame retardant can further react with resin with reactivity to obtain flame retarding resin. When the flame retarding resin is added to a polymer, the flame retarding property and the oxygen index of the polymer can be promoted, and the flame retarding level can reach Underwriters Laboratories (UL) 94V0.

The invention discloses a method for synthesizing a novel anti-influenza drug baloxavir marboxil. The method comprises the following steps: directly docking a thiosalicylic acid compound 1 and a 1-(halogenated methyl)-2,3-difluorobenzene compound 2 serving as initial raw materials so as to obtain a compound 3; performing PPA ring closure to obtain a 7,8-difluorodibenzo[b,e]thiozepine-11(6H)-one compound 4, and obtaining a key chiral thiazem intermediate compound 5 under catalysis of a chiral enzyme; directly condensating the compound 5 and a key chiral fragment compound 6 by virtue of a Mitsubobu reaction so as to obtain a compound 7; finally performing dealkylation protection, and condensating with ((methoxycarbonyl)oxo)4-methyl-toluenesulfonate, so as to obtain the final product compound9, namely the baloxavir marboxil. According to the synthetic route, the process operation magnification difficulty of the route is reduced, the production of by-products is reduced, the product purity is improved, and the cost of the route is reduced.

The invention discloses a synthesis method for a drug Roxadustat for chronic anemia. The synthesis method comprises the following steps: hydrolyzing and acidifying a compound shown as a formula 6 under the action of alkali to obtain a key intermediate compound shown as a formula 7; carrying out condensation reaction on the compound shown as the formula 7 and carbonyl diimidazole under suitable conditions to obtain an intermediate compound shown as a formula 8, and separating or not separating the compound shown as the formula 8 from a system to directly take part in subsequent reaction; and finally, reacting the product with glycine to obtain a final product Roxadustat shown as a formula 9. The preparation method has the advantages that the route efficiency is improved, the process cost isreduced, side products are reduced and the purity of a final product is favorably improved (The formula is shown in the description), wherein R2 in the compound shown as the formula 6 represents alkyl, and includes but not limited to methyl, ethyl, isopropyl, tertiary butyl or benzyl.

The invention discloses spicy flavor seasoning oil and a preparation method thereof. The spicy flavor seasoning oil is prepared by mixing supercritically extracted spice grease, plant oil, monoglycerol aliphatic ester, caprylic capric triglyceride and glycerol. The caprylic capric triglyceride and the glycerol are mixed in the seasoning oil, so that various spice extractives can be well diluted and dissolved; the tingling taste can be quickly released; the goal of releasing spicy tastes synchronously can be achieved; meanwhile, the heat resistance of the seasoning oil can be effectively improved; the monoglycerol aliphatic ester is used as an emulsifying agent, so that the grease can be dispersed more evenly; the stability of the mixed grease can be improved; the seasoning oil has the advantages of being strong in taste and rich in fragrance; the tingling taste and the piquancy can be released synchronously; the spicy flavor seasoning oil has the characteristic of good heat resistance; the application of product is facilitated; the concentration can be adjusted according to the requirement; the spicy flavor seasoning oil can be conveniently used in food processing industries in large scales; the spicy flavor seasoning oil is especially applicable to the deep processing industries of pickled vegetables such as pickled vegetables, preserved szechuan pickles, kelp vegetables, olio vegetables, pickled cucumbers, shredded mustard, flammulina velutipes and the like with the spicy flavor.

The invention discloses a novel method used for preparing high-purity 4-chloropyrrolo[2,3-d]pyrimidine in industrialization scale. According to the method, ethyl cyanoacetate, bromo-acetal, formamidine acetate, and sodium alcoholate are taken as raw materials; N,N-dimethylformamide, ethyl alcohol, and phosphorus oxychloride are taken as solvents; and 4-chloropyrrolo[2,3-d]pyrimidine is obtained via three-step approach. The process route of the method is simple; time is short; next step feed can be carried out directly without complex purification process of intermediates; no toxic agent is used; the method is safe and reliable, and is low in cost; total yield is higher than 30%; and the purity of obtained products is as high as 99.2%.

The invention relates to a pectin preparation method, belonging to the field of food processing and in particular relating to the pectin preparation method with low cost and high extraction rate. The preparation method comprises: 1, pretreatment of raw materials: taking fresh orange peel, chopping the orange peel until the particle size is 2-3mm, carrying out thermal treatment on the orange peel for 5 min in boiling water to deactivate pectinase, soaking the orange peel for 30 min in 70 percent of ethanol, keeping the orange peel for 5 min at 70-90 DEG C, carrying out pressure filtration to remove pigments and other impurities soluble in alcohol, washing residues with 95 percent of ethanol and then washing with ethyl ether, minimizing the loss of water-soluble pectin, air-cooling the ethyl ether, and drying at 45 DEG C until the constant weight is achieved; and 2, acid hydrolysis and extraction: adding hydrochloric acid solution into the pretreated raw materials, heating the mixture in a constant-temperature water bath, mixing well, and centrifuging until the supernatant is not sticky, and fixing the volume of the supernatant, i.e. pectin extract, to be 100ml.

The present invention provides a new synthesis method of a baricitinib compound 11. According to the present invention, by using a compound 1 as a staring raw material, the amino group is protected by directly using ethanesulfonyl chloride, and direct cyclization is directly performed by using the effect of an alkali to obtain a key intermediate compound 3 so as to avoid the use of other protection groups and substantially improve the route efficiency and the atomic economy; during the compound 5 preparation, a Wittig reaction is performed by using triphenylphosphine acetonitrile so as to avoid the use of strong alkali and improve the reaction yield; the completely-new neopentyl glycol borate derivative compound 8 has good stability and good crystallinity so as to simplify the separation and purification process; and the route is simple to operate and has the high yield, the purity of the obtained product is high, and the synthesis method is suitable for amplification production. The formulas 1-11 are defined in the specification.

The invention relates to a method for preparing electrophoretic particles by using an organic pigment. Specifically, the invention discloses the method for preparing electrophoretic display particles. The electrophoretic display particles comprise core particles and modifying layers covering on the surfaces of the core particles. The method comprises the following steps: suspending the core particles in a first solvent and adding an alkali into the first solvent to perform alkalization so as to form a first suspension; suspending tetraethyl orthosilicate in a second solvent to form a second suspension; adding the second suspension into the first suspension, and further stirring at the increased temperature to perform the reaction; adding a silane coupling agent containing an amino group into a mixture in the step (3), stirring to perform the reaction and further obtaining pre-modified particles connected with the silane coupling agent; dispersing the obtained pre-modified particles in a third solvent, adding polymer monomers, and uniformly mixing; and adding an initiator to perform polymerization reaction to enable the polymer monomers to be polymerized on the surfaces of the pre-modified particles to form the surface modifying layers, and further obtaining the electrophoretic display particles. The electrophoretic particles obtained by the method disclosed by the invention have the significant improved apparent performance.

The invention provides a preparation method of an intermediate compound 7 of an SGLT-2 diabetes inhibitor dapagliflozin and an intermediate compound 8 of a SGLT-2 diabetes inhibitor empagliflozin, and new synthesis method of two final products. The preparation method comprises the following steps: carrying out carbonyl group reduction and hydroxyl group protection on a (5-halo-2-chlorophenyl)(4-ethoxyphenyl)ketone compound 1 used as an initial raw material to obtain a Grignard addition reaction key compound 4, and carrying out Grignard addition and acetylation to obtain the compound 7 and the compound 8. The dapagliflozin and the empagliflozin are respectively prepared from the compound 8. The methods have the advantages of simplicity in operation, high yield, high purity of the obtained products, and suitableness for amplified production.

The invention relates to a preparation method for poly(2,5-dihydroxyl-1,4-phenylene pyridobisimidazole). The preparation method is realized by the following synthetic method: 2,3,5,6-tetraminopyridine (TAP) hydrochloride and 2,5-dihydroxyl-terephthalic acid (DHTA) are used as raw materials to carry out salificaton by an acid-base neutralization reaction so as to obtain 2,3,5,6-tetraminopyridine-2,5-dihydroxyl-terephthalate composite salt (TD salt); then high molecular weight PIPD fibers are prepared by temperature programmed solution polymerization in a polyphosphoric acid (PPA) system. The method solves the problems of low molecular weight and harsh polymerization conditions of a conventional method, aiming at the difficulties that amino groups are easily oxidized and equimolar ratio reaction can be kept in a whole process. The TD salt obtained by the process for synthesizing the 2,5-dihydroxyl-terephthalc acid-2,3,5,6-tetraminopyridine (TD) composite salt is stable in quality and easy to store; the polymerization reaction combines the advantages of a direct method and a TD salt method, so that the PIPD polymer with higher molecular weight is obtained without changing polymerization environment and polymerization equipment.

The invention relates to chiral supramolecular nucleoside hydrogel based on a boron ester bonds as well as a preparation method and application of the chiral supramolecular nucleoside hydrogel, and particularly provides supramolecular hydrogel which is obtained by mixing guanine nucleoside and borate as raw materials in a solvent, wherein the guanine nucleoside is D-guanine nucleoside and / or L-guanine nucleoside. The supramolecular hydrogel has excellent stability, injectability and self-repairability, also has good biocompatibility, does not show obvious acute toxicity in animal bodies, can be degraded in vivo, and can be used as an extracellular matrix for 3D culture of cells. The supramolecular hydrogel provided by the invention has a very good application prospect in the field of tissue engineering as a scaffold material.

The invention belongs to the technical field of chemical drug synthesis, and particularly relates to a preparation method of an isoxazoline insectifuge. The preparation method is characterized in thatthe isoxazoline insectifuge is fluralaner; an intermediate I is sequentially subjected to an amidation condensation reaction, a substitution reaction and a ring closing reaction in the same reactioncontainer; and after the reactions are finished, a reaction product is poured into water, stirring and filtering are conducted to obtain a solid, and the obtained solid is recrystallized to obtain theisoxazoline insectifuge. The method has the beneficial effects that the method uses a solvent and one-pot method to synthesize fluralaner, technological operation of a synthesis process is reduced, treatment time and reaction time are shortened, product yield is improved, and the method is suitable for large-scale production.

The invention provides a novel synthetic method of Palbociclib, comprising the following steps: 1) under the action of alkali and a solvent, an intermediate V and an intermediate B1 undergo a condensation reaction to obtain a compound VI; 2) the compound VI undergoes exchange with a Grignard reagent, and then the exchange reaction product reacts with an acylation reagent to obtain a compound VII; when X is acetyl, the compound VI is the compound VII; 3) the compound VII undergoes deprotection reaction under the action of hydroxyethanesulphonic acid and finally salification is conducted so as to obtain the finished product Palbociclib X. the synthetic method has a simple process route, is low-cost, and is suitable for industrial production. The synthetic route is as shown in the specification.

The invention discloses a method for synthesizing apalutamide. The method includes carrying out condensation on N-methyl-2-fluorine-4-halogenated-benzamide compounds 1 and amino-1-cyclobutanecarboxylic acid hydrochloride 2 by means of Ullmann reaction to obtain to obtain intermediate compounds 3 and esterifying the intermediate compounds 3 to obtain intermediate compounds 4; carrying out cyclization by means of reaction on the intermediate compounds 4 and thiocyanide to obtain compounds 5; carrying out condensation by means of coupling the compounds 5 to obtain the apalutamide. The N-methyl-2-fluorine-4-halogenated-benzamide compounds 1 and the amino-1-cyclobutanecarboxylic acid hydrochloride 2 are used as starting materials. A path is shown, an R in the path represents alkyl, includes butis not limited to methyl or ethyl. The method has the advantages that route steps can be shortened to a great extent, the route efficiency can be improved, precious metal catalysts are omitted, and accordingly the process cost can be lowered; byproduct generation can be reduced, and accordingly the method is favorable for improving the purity of ultimate products.

The invention provides a cathode active material of a lithium ion secondary battery. The cathode active material comprises a carbon material core and a coating layer formed on the surface of the carbon material core, wherein the coating layer contains amorphous carbon and doping elements, and the doping elements include a nitrogen element. A carbon material is taken as a core of the cathode active material for the lithium ion secondary battery, and the coating layer containing the amorphous carbon and doping elements is arranged on the surface of the carbon material, so that the cathode active material has the advantages of long service life, high capacity, high magnifying power charge and discharge characteristics and low cost; by utilizing the cathode active material, the charging velocity of the battery can be effectively increased, and particularly, the rapid charging capacity of the battery at a low temperature can be effectively increased. The invention further provides a preparation method of the cathode active material, a cathode pole piece of the lithium ion secondary battery and the lithium ion secondary battery.

The invention provides a process for preparing ethyl trifluoroacetate through a continuous non-catalytic method reaction of trifluoroacetyl chloride and ethanol under a reactive rectification condition. The process has the characteristics of conveniently and easily available raw materials, simple process, mild reaction conditions, low reaction energy consumption, and no waste liquid residue in the procedure, and is suitable for amplification production. The prepared ethyl trifluoroacetate can be used for synthesis of fluorine-containing pesticides, fluorine-containing medicines, fluorine-containing liquid crystals, fluorine-containing dyes and the like.

The invention relates to a coating having both luminous and fluorescent properties, and a preparation method thereof, and belongs to the technical field of luminous coatings. The coating comprises 1-3% of a carbon dot dioxide fluorescent material, 1-4.5% of an organic long-afterglow luminous material, 27-45% of a silicone-modified waterborne polyurethane emulsion, 18-36% of a pigment, 9-18% of a filler, 0.2-0.9% of a wetting dispersant, 0.2-0.9% of a defoaming agent, 0.1-0.45% of a leveling agent, 0.45-1.8% of a thickener, 1.0-3.0% of a film forming aid, and the balance of water. The components constituting the coating are reasonably selected and the use amounts of all the components are controlled to ensure that the finally prepared coating has an obvious luminous phenomenon and a good adhesion. The coating has both fluorescent and luminous properties, is non-polluting and nontoxic, and is environmentally friendly, so the coating has broad application prospects in the fields of anti-counterfeiting, decoration and public transportation. In addition, the preparation method has the advantages of simple process, easiness in operation, low raw material cost, and suitableness for enlarged production.

The invention discloses a molybdenum sulfide functional carbon nano tube Pt-carried catalyst for a direct methanol fuel cell and a preparation method of the catalyst. The preparation method comprises the following steps of: 1) preparing a PANI-modified multi-wall carbon nano tubes (MWCNTs) composite material polyaniline (PANI)-MWCNTs; 2) preparing a molybdenum sulfide functional MWCNTs composite material MoS2-MWCNTs; and 3) obtaining the molybdenum sulfide functional MWCNTs Pt-carried catalyst Pt / MoS2-MWCNTs. The method is simple in process flow, high in controllability and low in cost, is applicable for production at a large scale and has favorable application prospect; and the catalyst prepared according to the method is represented with the characteristics of high electrocatalytic activity on methanol oxidization, high stability and high ability of resisting CO poison.

The invention provides a preparation method of novel Brexpiprazole and salts thereof, aripiprazole and salts thereof, or key intermediates thereof. The method uses a starting material of 7-hydroxycoumarin or 7-hydroxy dehydrocoumarin, which is subjected to a substitution reaction, a dehydrogenation reaction and / or amination reaction. The method has the advantages of sufficient supply of easily available raw materials, low cost, high safety, simple operation, high product yield and good quality, and is suitable for enlarge production.

The invention discloses a synthesis method of myricetin. The method includes the steps of: adding an alkaline solution into a dihydromyricetin aqueous solution, and then performing heating under a reflux state; adding a selenium dioxide aqueous solution, then stirring at a reflux temperature for reaction, and then performing cooling to room temperature; adding acid to adjust the pH value, conducting stirring and rotary evaporation, and then performing stirring and filtering; adding an ethanol aqueous solution into a filter cake, performing pulping and filtering, flushing the filter cake with an ethanol aqueous solution, collecting the filter cake, and performing drying to obtain red selenium; combining an organic phases, and performing spin-drying till no ethanol smell, precipitating a large amount of solid, performing filtering, and flushing the filter cake with an ethanol aqueous solution to obtain a yellow solid, i.e. myricetin. The method has the advantages that: 1, the reaction issimple and easy to operate; 2, water and a small amount of ethanol are mainly used as the solvent, and the emission of three wastes is low; 3, red selenium with economic value can be recovered; 4, the obtained myricetin is high in purity; and 5, the method can achieve multiple purposes, has very good economic benefits, and is suitable for large-scale production.

The invention discloses florfenicol included controlled-release granules, prepared by developing an inner core made by florfenicol inclusion, with a controlled-release film. The invention further discloses a method of preparing the florfenicol included controlled-release granules and its application in the preparation of veterinary antibiotics. Compared with the prior art, the florfenicol included controlled-release granules has the advantages that solubility of florfenicol and bioavailability thereof are effectively improved, the granules can release fast in the early stage of administering to minimum antibiotic concentration, resulting in efficacy and can release slowly later, the efficacy is kept long, and no toxic or side effects occur; meanwhile, the materials for use in the preparing method are safe and easy to obtain, and the preparing method is suitable for wider range of production.

The invention relates to a titanium-based active bone implant and a preparation method thereof, which belong to the technical field of a medical material. The method comprises the following steps: after dopamine is loaded on the surface of pure titanium, a gelatin solution, a dextran amine solution, a gelatin solution, an alpha-melanocyte stimulating hormone solution are subjected to spin coatingin order, wherein spin coating of the gelatin solution, the dextran amine solution, the gelatin solution, and the alpha-melanocyte stimulating hormone solution in order is called the complete spin coating, the number of complete spin coatings is determined according to the actual required release amount of the alpha-melanocyte stimulating hormone, a layer of the gelatin solution is spin-coated after the last complete spin coating is completed, and the material immersed in a solution of a graft polymer formed by grafting right-arm polyethylene glycol amino group with a boric acid ester bond formore than 2 h to prepare the titanium-based active bone implant. The bone implant can release a large amount of alpha-MSH in a short time to reach the effect concentration, and has the ability to promote osteogenic differentiation of bone-related cells. The preparation method of the titanium-based active bone implant is simple and easy to operate, and is suitable for expanding production.

The invention relates to a high-ductility low-temperature quick-degraded magnesium alloy and a preparation method thereof, and belongs to the technical field of magnesium alloy materials. The alloy comprises the following components in percentage by mass: 5.0-6.5% of Gd, 0.1-0.25% of Ni, 0.05-0.5% of Zr and / or 0.4-1.0% of Mn, inevitable impurity not more than 0.3%, and the balance of Mg. The effects of various alloy elements are considered; the synergistic effect of the alloy elements is used for obtaining the magnesium alloy with high plasticity and higher low-temperature degrading speed; thealloy is few in element type, low in element adding quantity and low in cost, so that the alloy preparation cost is not obviously increased; and compared with a commercial magnesium alloy, the magnesium alloy is small in change of the preparation process and suitable for mass production.

The invention discloses a method for synthesizing enantiomorphous pure symmetric trans-dialkyl cyclohexylamine, belonging to the field of chemistry. The method comprises the following steps of: carrying out an airtight or reflux reaction on cyclohexene oxide and an aqueous solution of alkylamine for reacting at 80-120 DEG C for 1.5-5h to obtain 2-alkyl-amino cyclohexanol, dropwise adding DEAD (Diethyl Azodicarboxylate) or DIAD (Diisopropyl Azodicarboxylate) to triphenylphosphine, 2-alkyl-amino cyclohexanol and a solvent under an ice bath for reacting for 5-20h at room temperature to obtain N-alkyl-7-azabicyclo[4, 1, 0]heptane, adding a catalyst to the N-alkyl-7-azabicyclo[4, 1, 0]heptane and the aqueous solution of alkylamine at 100-120 DEG C to carry out the airtight or reflux reaction to obtain trans-N,N'-dialkyl-1,2 cyclohexanamine, dissolving the trans-N,N'-dialkyl-1,2 cyclohexanamine in an alcoholic solvent, and adding a tartaric acid type resolving agent with the equivalent weight of 0.5 to the alcoholic solvent to resolve so as to obtain the enantiomorphous pure symmetric trans-dialkyl cyclohexylamine.

The invention discloses polyimide / multi-walled carbon nanotube / nano ferroferric oxide composite aerogel and a preparation method thereof, and particularly provides polymer-based composite aerogel which is prepared by taking a polymer as a matrix and taking a carbon material and a magnetic loss material as fillers. Wherein the polymer is a water-soluble polymer and / or a polymer with a water-solubleprecursor. Compared with polyimide-based composite aerogel obtained by only adding one functional filler of MWCNTs or Fe3O4, the polyimide-based composite aerogel obtained by simultaneously adding MWCNTs and Fe3O4 has the advantage that under the condition that the functional filler with the same content is added, the wave-absorbing property of the polyimide-based composite aerogel achieves a synergistic effect. The polymer-based composite aerogel provided by the invention has an anisotropic ordered pore structure, lower density, good thermal stability, significantly improved electromagneticwave absorbing performance and excellent comprehensive performance, and has a very good application prospect as an electromagnetic wave absorbing material in civil and military fields.

The invention discloses a method for synthesizing 2,3-dimethyl-4-fluorophenol. The method comprises the following steps: adding aluminum trichloride in 2,3-dimethylfluorobenzene at a normal temperature and carrying out bromination reaction to obtain 3-bromo-6-dimethylbenzene; carrying out methoxylation on the 3-bromo-6-dimethylbenzene under the effect of N,N-dimethylformamide and sodium methoxideto obtain 3-methoxyl-6-dimethylbenzene; and carrying out hydrolysis on the 3-methoxyl-6-dimethylbenzene to obtain 2,3-dimethyl-4-fluorophenol. According to the synthesizing method, the 2,3-dimethylfluorobenzene which is low in price is used as a reaction raw material, in every step of reaction, an intermediate which is high in purity can be obtained to a maximum extent, thus, the total yield of total reaction is high, the purity of the final product reach up to 98% or above, the economic benefit is quite obvious, and the method is particularly suitable for industrial large-scale application and popularization.

A carbon fiber composite emulsion sizing agent having low viscosity is disclosed. The main components of the sizing agent comprise: 20-60% of aliphatic polyester polyol, 20-60% of bisphenol F epoxy resin, 10-20% of an anionic surfactant, 0.5-5% of an antioxidant and 0.5-5% of a levelling agent. A preparing process of the sizing agent includes (1) a step of mixing resin, (2) a step of adding auxiliary agents, (3) a step of adding deionized water, and other steps. According to the prepared sizing agent, the emulsion solid content is 30-60%, the emulsion pH is 6.0-8.0, the emulsion average particle size is 100-300 nm, and the emulsion surface tension is less than 45 mPa.s. The prepared sizing agent is high in inner fluidity and high in uniformity degree. Sized carbon fiber is low in difference between inner and outer sizing amounts and is better and more stable in performance.