34 results about "Trimellitic acid" patented technology

This invention provides a method for recovering and utilizing distillation residue after solvent removal from homohydric anhydride, relating to the field of fine chemical technology. The method includes anhydride treatment, vaporization and sublimation, dissolution and recrystallization, distillation, and water washing. In this invention, the distillation residue is anhydride-treated under high temperature and negative pressure, followed by vaporization and sublimation under vacuum to separate mechanical impurities and high-boiling substances. Then, through dissolution and recrystallization, the difference in solubility between homohydric anhydride and metahydric anhydride in polar solvents is utilized to preferentially crystallize out the homohydric anhydride. The mother liquor is distilled to remove the solvent, and then colored impurities are removed by hot water washing and activated carbon adsorption. Finally, it is cooled and crystallized to obtain trimellitic acid. The homohydric anhydride obtained by this invention has a purity ≥95% and a yield of 84-89%, and the trimellitic acid has a purity ≥97% and a yield of 81-86%. This method achieves effective recovery of high-value-added components from distillation residue, demonstrating significant economic and environmental benefits and promising application prospects.

A plasticizer composition contains a compound of the formula (1)and at least one trialkyl trimellitate, where the three alkyl groups in the trialkyl trimellitate each have 8 or 9 carbon atoms.

The utility model discloses a kind of trimellitic acid trioctyl continuous method stripping dealcoholization process research and development device, it is related to trimellitic acid trioctyl continuous method stripping dealcoholization technical field, its technical scheme main point is: including stripping column, stripping column inside is connected with silk screen by multiple bolts, wherein, stripping column is located silk screen lower end and is provided with cleaning mechanism, for the impurity on silk screen is cleaned, the cleaning mechanism is provided with conveying mechanism, for the impurity on silk screen is transported after cleaning, stripping column is provided with receiving mechanism, for the impurity transported by conveying mechanism is concentrated and received, effect is thereby solve the problem in background art that need greater power to maintain gas flow, lead to energy consumption increases substantially, simultaneously, after silk screen aperture is blocked by impurity or by-product, originally designed droplet interception capacity will reduce.

The invention relates to the technical field of preparation of antibacterial materials, in particular to a two-dimensional nickel (II) coordination polymer as well as a preparation method and antibacterial application thereof. The preparation method comprises the following steps: mixing a dpb solution, a btc solution, a Ni (NO3) 2 solution, acetonitrile and water, carrying out a solvothermal reaction for 4-5 days, carrying out natural cooling crystallization, washing and drying to obtain [Ni3 (dpb) 2 (btc) 2 (H2O) 2] n, and according to the complex, nickel (II) has two coordination modes, and nickel (II) is coordinated with carboxyl oxygen atoms of two trimesic acid, oxygen atoms of two water molecules and nitrogen atoms of two ligands; nickel 2 (II) is coordinated with three nitrogen atoms of a ligand and three oxygen atoms of two trimesic acids to form a one-dimensional ladder-shaped chain structure, and the ladder-shaped chain is further bridged with the ligand to form a two-dimensional layered structure. The compound has very good thermal stability, has a good inhibition effect on staphylococcus aureus and escherichia coli, is non-toxic to human embryo kidney cells in 24 hours and 48 hours, and can be used as a bacteriostatic drug material carrier in the aspect of medicine.

The invention discloses a preparation method and application of benzenetricarboxylic acid isomer modified chitosan, and the preparation method comprises the following steps: step 1, respectively dissolving trimesic acid, trimellitic acid and trimellitic acid in a sodium hydroxide solution to obtain a benzenetricarboxylic acid solution; 2, dissolving chitosan with an acetic acid solution to obtain a chitosan mixed liquid; 3, slowly adding the benzenetricarboxylic acid solution obtained in the step 1 into the chitosan mixed liquid obtained in the step 2, and continuously stirring to react until a white gel material is formed; and 4, filtering the white gel material prepared in the step 3, washing to be neutral, and drying to obtain the adsorbent. The three adsorbents prepared by the invention all have unique space structures and surface chemical characteristics, and anionic polymer chains of the adsorbents are rich in carboxyl, carbon-carbon double bonds, carbonyl and other functional groups, so that high-selectivity adsorption of rare earth metal lanthanum ions can be realized, and the adsorbent is suitable for recognition, separation and recovery of lanthanum ions in water with complex components.

The invention discloses a photovoltaic cable, and relates to the technical field of cables, and the photovoltaic cable comprises an insulating layer. The insulating layer comprises the following components in percentage by mass: 45%-48% of polyvinyl chloride resin with the polymerization degree of 2500, 20%-24% of a heat-resistant plasticizer, 5.7%-7% of a heat stabilizer, 1.13%-1.18% of an antioxidant, 12%-15.5% of a flame retardant, 6%-7.5% of a filler, 2.25%-2.4% of a processing aid, 0.5%-1.5% of a lubricant and 0.02% of a coloring agent; wherein the heat-resistant plasticizer is prepared from trioctyl trimellitate, tridecyl trimellitate and epoxidized soybean oil; or the heat-resistant plasticizer comprises trioctyl trimellitate and tridecyl trimellitate. The specific heat-resistant plasticizer, the flame retardant, the heat stabilizer, the antioxidant, the filler, the processing aid, the lubricant and the coloring agent are introduced according to a certain mass ratio on the basis of the high-polymerization-degree polyvinyl chloride, so that the photovoltaic cable has good heat resistance and flame retardance.

The application provides a sandwich-structured photocatalyst, which is constructed by TiO2 nanosheets and a Co-Fe / MOF with bimetallic activity, the TiO2 nanosheets are covered on the surface of the Co-Fe / MOF to form a layered sandwich structure, and the Co-Fe / MOF is a metal organic framework compound prepared from a precursor of uniform trimellitic acid, cobalt and iron. The precursor of cobalt and iron is stirred and dissolved in an organic solvent, the TiO2 nanosheets are dispersed and immersed in the precursor solution, then the uniform trimellitic acid is added into the immersion liquid to be stirred and ultrasonically dispersed, and then the reaction is carried out in an autoclave by heating, the reaction liquid is centrifuged, washed and vacuum dried to obtain the sandwich-structured photocatalyst TiO2NS@Co-Fe / MOF. The preparation method of the sandwich-structured photocatalyst is simple in reaction system and simple in preparation process, and is suitable for large-scale production. The photocatalyst prepared by the application combines the double functions of the TiO2 nanosheet photocatalysis and the Co-Fe / MOF heterogeneous Fenton interface catalysis, plays a synergistic effect, and can effectively degrade phenolic substances in wastewater.

The present invention provides a method for preparing an ester-based material, the method including a step in which in a batch reactor, under a catalyst, at least one polycarboxylic acid selected from the group consisting of a terephthalic acid, a phthalic acid, an isophthalic acid, a cyclohexane dicarboxylic acid, a cyclohexane tricarboxylic acid, a trimellitic acid, and citric acid reacts with at least one mono-alcohol having 3 to 12 alkyl carbon atoms, wherein pressure in the reactor is configured such that the pressure at the early stage is 0.3 barg to 1.0 barg and the pressure at the latter stage is 0 barg to 0.5 barg, the pressure at the early stage being greater than the pressure at the latter stage, and the early and latter stages are divided based on any one of the time points when reaction conversion rate is 30% to 90%.

The present application relates to a kind of quantitative determination electronic cigarette liquid trimellitic acid, p-phthalic acid, m-phthalic acid method, belong to electronic cigarette liquid component detection technical field, it is characterized in that: using to electronic cigarette liquid sample adds certain concentration of formic acid aqueous solution extraction and improves the acid-base environment of sample, further purify sample by vortex, filtration, using core-shell (surface porous) reversed-phase chromatographic column, realize the complete separation of three target objects, combined with liquid chromatography mass spectrometer technology, internal standard method quantitative, realize the accurate detection of trimellitic acid, p-phthalic acid, m-phthalic acid in electronic cigarette liquid.The present application has the advantages that simple operation, quantitative accurate, high sensitivity, target can be extracted from complex electronic cigarette liquid matrix and accurately quantified, can satisfy the accurate detection of trimellitic acid, p-phthalic acid, m-phthalic acid in electronic cigarette liquid.

The application discloses a kind of fabric whole core flame-retardant conveying belt rubber and plastic fiber flame-retardant covering gum and preparation method thereof, including the following components: FR-PVG powder, polyvinyl chloride, chlorosulfonated polyethylene rubber, magnesium oxide, epoxy resin, accelerator DM, accelerator TRA, conductive carbon black, trimellitic acid trioctyl ester, flame retardant, epoxy soybean oil, ammonium polyphosphate melamine, antimony trioxide, calcium-zinc composite stabilizer, coupling agent, PE wax, 10wt% sulfuric acid solution, methacrylic acid, dicumyl peroxide;The application utilizes FR-PVG as matrix to prepare rubber and plastic fiber flame-retardant covering gum, avoids environmental pollution problem caused by processing FR-PVG, realizes green recycling and high-value utilization of FR-PVG, and innovates a new way of high-value and efficient green recycling and utilization of waste rubber and plastic fabric whole core flame-retardant conveying belt.

The application discloses a sleeve material for heat-shrinkable terminals, which is prepared from the following raw materials in parts by weight: 100 parts of polyetherimide, 10-30 parts of polycarbonate, 20-40 parts of trizinc trimellitate, and 2-8 parts of nano-zinc stannate. The application also discloses a preparation method of the sleeve material for heat-shrinkable terminals and heat-shrinkable terminals prepared therefrom. The sleeve material for heat-shrinkable terminals has the characteristics of high strength and transparency, low water absorption, excellent high-temperature resistance and flame resistance, and good processability, and has better comprehensive performance.

The invention relates to an integrated preparation process of low-residue trioctyl trimellitate, which comprises the following steps: carrying out ring-opening reaction on trimellitic anhydride and 2-ethyl hexanol under the protection of inert gas; then adding a main catalyst to carry out first-stage esterification reaction; then adding a cocatalyst to carry out a second-stage esterification reaction, after the esterification reaction is finished, carrying out first treatment on the reaction liquid by using a 2-5% dilute sodium carbonate or sodium hydroxide solution, then adjusting the pH value of the reaction liquid subjected to the first treatment to 2-3 by using dilute sulfuric acid or hydrochloric acid, and carrying out countercurrent washing by using hot water; adding excessive organic acid into the reaction liquid for reaction to obtain esterification reaction liquid after the catalyst is recycled; and finally, sequentially adsorbing, filtering and refining to obtain the low-residue trioctyl trimellitate. According to the method, a multi-element catalyst system and a step-by-step esterification process are adopted, and esterification reaction liquid after reaction is treated in a three-step treatment mode, so that efficient recovery of a catalyst is realized, and residues of the catalyst in trioctyl trimellitate are effectively reduced.

This invention provides a high-reliability halogen-free solder paste flux, its preparation method, and its application, relating to the field of soldering materials. The flux comprises a solvent, a film-forming agent, an activator, a thixotropic agent, and functional additives. The film-forming agent is composed of polymeric rosin, hydrogenated rosin glycerol ester, and trimellitic acid. Based on 100% of the total flux weight, the polymeric rosin content is 18%–26%, the hydrogenated rosin glycerol ester content is 10%–18%, and the trimellitic acid content is 0.5%–2%. The preparation method includes: uniformly mixing the raw materials under vacuum conditions, heating, high-speed shear emulsification treatment, and cooling. The high-reliability halogen-free solder paste consists of flux and alloyed tin powder, with the flux accounting for 9%–12% of the solder paste's mass. This invention ensures excellent soldering performance while completely eliminating halogen risks, significantly reducing post-soldering residues, and improving surface insulation resistance, meeting the stringent requirements of high-reliability electronic assembly.

The application discloses a ZnIn2S4 / MOF-based S-type heterojunction composite photocatalyst and a preparation method and application thereof. The preparation method comprises the following steps: S1, preparing MOF-808: taking a zirconium salt as a metal source and a uniform trimellitic acid as an organic ligand, and performing an oil bath heating reaction in the presence of a control agent, and after the reaction is completed, centrifugal washing and drying treatment are performed to obtain the MOF-808; S2, in-situ growth of ZnIn2S4: dispersing the MOF-808 prepared in the step S1 in a mixed solvent, performing ultrasonic treatment to form a uniform suspension, sequentially adding a zinc source, an indium source and a sulfur source, and then performing a hydrothermal reaction after uniform stirring. The S-type ZnIn2S4 / MOF heterojunction structure constructed by the ZnIn2S4 / MOF-based S-type heterojunction composite photocatalyst and the preparation method and application thereof can reach a visible light degradation rate of 88.5% on tetracycline, and still maintains high activity and structural stability after multiple cycles, and exhibits good anti-interference ability and repeated use performance.

The present invention relates to a plasticizer composition containing a trimethyl ester of cyclohexane-1, 2, 4-tripropionic acid and a trialkyl trimellitate. The present invention relates to a plasticizer composition comprising a compound of formula (1) and at least one trialkyl trimellitate wherein the three alkyl groups in the trialkyl trimellitate each have 8 or 9 carbon atoms.

The invention relates to a method for extracting a trimellitic anhydride effective component in a trimellitic anhydride heavy component and preparing trioctyl trimellitate, which comprises the following steps: by taking the trimellitic anhydride heavy component and ethanol as raw materials, carrying out ethyl esterification under the action of a catalyst to generate triethyl trimellitate, and then distilling to obtain high-purity triethyl trimellitate. And carrying out transesterification on triethyl trimellitate to obtain a trioctyl trimellitate finished product. The trimellitic anhydride heavy component contains 20-30% of trimellitic anhydride effective component, trimellitic anhydride in the trimellitic anhydride heavy component is effectively extracted through ethyl esterification and distillation operation by utilizing the characteristic that the boiling point of triethyl trimellitate is low, and a trioctyl trimellitate finished product is prepared. According to the method, the trimellitic anhydride heavy component is effectively recycled, so that the waste treatment cost is reduced, and the raw material utilization rate is increased.

The utility model relates to the technical field of equipment for crystallizing to form anhydride, and particularly discloses continuous equipment for crystallizing trimellitic anhydride to form anhydride, which comprises a feeding section, a multi-stage crystallizing section, a blanking kettle and a plurality of layers of gas-phase pipelines, meanwhile, the conical flash plate and the inverted conical flash plate are in jacket design, and high-temperature hot water is introduced into the conical flash plate and the inverted conical flash plate to improve the light component removal crystallization efficiency; the multi-stage crystallization section comprises a plurality of sets of conical heating plates and inverted conical heating plates; high-temperature hot water and heat-conducting oil are respectively introduced into the heating plates and are used for light component removal crystallization of trimellitic acid; and the material enters the blanking kettle after the light crystal removal process and is heated and insulated through a jacket. The device is used for continuous production of trimellitic anhydride light component removal crystals, and has the advantages of simple structure, high heat exchange efficiency and good crystallization effect compared with the existing domestic equipment.

[Problem] To provide a method for producing spherical aggregates of silver particles, the method enabling easy production of aggregates in which silver nanoparticles are spherically aggregated. The produced spherical aggregates of the silver nanoparticles have excellent dispersibility and excellent handling properties, exhibit electrical conductivity when sintered at low temperatures, and are suitable for use as a conductive filler. [Solution] A method for producing spherical aggregates of silver particles by adding one or more additives selected from the group A described below to a silver compound solution and a reducing agent solution. Group A: citric acid, citric acid anhydride, a citrate, trimellitic acid, trimellitic acid anhydride, and a trimellitate.

The invention discloses a device and a process for continuous oxidation of unsym-trimethylbenzene. The device comprises a bubbling oxidation reaction tower, a kettle type oxidation reactor and an external circulation unit, the outer circulation unit comprises a circulation pump and a circulation cooler which are connected in series. According to the method, unsym-trimethylbenzene is used as a raw material, two oxidation reactors which are operated in series are used, and trimellitic acid is produced through continuous oxidation by adopting a liquid-phase air oxidation method. The first oxidation reactor adopts a bubbling oxidation reaction tower with an external circulation unit, the second oxidation reactor is a lower stirring kettle type oxidation reactor, and the adoption of a graded oxidation scheme is beneficial to reducing investment and consumption, and achieves a technical effect better than that of the prior art.

The invention belongs to the technical field of chain lubricating oil, and particularly relates to high-temperature-resistant and anti-coking synthetic ester type chain oil as well as a preparation method and application thereof. According to the synthetic ester type chain oil provided by the invention, the specific dipentaerythritol ester and the trimellitate are synergistically used as synthetic ester base oil, the synthetic ester base oil is optimally compounded with the anti-wear reagent at extreme pressure, the antioxidant and the anti-rust agent, the synergistic effect among the components is utilized, and under the condition that a viscosity index improver is not added, the synthetic ester type chain oil can be used for preparing the high-viscosity chain oil. The synthetic ester type chain oil which is good in low-temperature fluidity, high in flash point, low in friction coefficient, small in wear scar diameter, low in corrosivity, excellent in adhesion performance, small in evaporation loss and free of coking at the high temperature of 300 DEG C is obtained, and the requirement for long-acting lubrication in a continuous high-temperature environment is met.

The invention relates to the technical field of organic synthesis processes, in particular to a method for improving esterification reaction efficiency of trioctyl trimellitate. Comprising the following steps: adding octanol into a reaction kettle I, heating to 150-180 DEG C, and carrying out heat preservation and temporary storage; adding solid trimellitic anhydride into a reaction kettle II, heating until the solid trimellitic anhydride is dissolved, then adding a modified tetraisopropyl titanate catalyst and activated carbon, and then transferring materials in the reaction kettle II into the reaction kettle I; and heating the reaction kettle I to 200-220 DEG C, and carrying out esterification reaction. According to the method, the modified tetraisopropyl titanate catalyst and the activated carbon are added into the dissolved trimellitic anhydride to accelerate the subsequent esterification reaction and improve the subsequent conversion rate, the activated carbon is used for synchronously adsorbing impurities generated in the subsequent esterification reaction, and then the activated carbon and the octanol are mixed and react, so that the conversion rate is improved to 98% or above. In the step 3, the temperature in the reaction kettle I is controlled in a gradient manner, so that the reaction is balanced, the esterification reaction is promoted to be carried out more thoroughly, and the conversion rate is further improved.

The application discloses a kind of metal organic framework composite material and its preparation method and application, preparation method includes: preparation includes uniform benzene trimellitic acid, polymer and first solvent spinning fluid, electrostatic spinning is carried out, obtains fiber or fiber membrane, it is immersed in copper acetylacetonate solution, reaction, generates metal organic framework composite material;The reaction time of control reaction is greater than or equal to 60min, copper acetylacetonate solution is prepared by dispersing copper acetylacetonate in second solvent;The method can make metal organic framework (Cu-BTC) on the surface of polymer fiber with mild conditions Realize heterogeneous nucleation and the high load controlled growth of hexagonal flaky crystal form, crystal structure defect is less, it is favorable to improve the performance of composite material, and then it is favorable to be applied in preparation of heterogeneous catalytic material, drug delivery material, gas adsorption material or environmental remediation material.

A grease composition includes: (A) a trimellitic acid ester, (B1) a phenyl α naphthylamine, (B2) an alkyl diphenylamine, (C1) a succinic acid half ester, (C2) a sorbitan monoester, and (D) a urea-based thickener. This grease composition is excellent in anti-flaking, rust prevention, and oxidation resistance properties, and furthermore, a fatigue life of a rolling device and the like in which the grease is enclosed can be maintained for a long time.

The invention discloses a green epoxy resin regenerant and an application method thereof in asphalt regeneration. The regenerant is prepared from the following components in parts by weight: 36 to 39 parts of vegetable pitch, 16 to 22 parts of base oil, 13 to 16 parts of organic silicon modified bisphenol A epoxy resin, 3 to 4 parts of rosin modified phenolic resin, 5 to 6.5 parts of hydrothermal modified halloysite nanotube, 1.5 to 2.5 parts of nano titanium dioxide, 2.2 to 2.8 parts of silane coupling agent, 1.3 to 1.7 parts of trioctyl trimellitate, 1.2 to 1.5 parts of anti-aging agent and 0.4 to 0.6 part of catalyst. According to the preparation method disclosed by the invention, a nano modification process is upgraded to a hydrothermal modification and silane coating composite process from pure silane coupling, and a surfactant hexadecyl trimethyl ammonium bromide is introduced to assist dispersion, so that the problem of nano agglomeration in the prior art is solved; the composite nano material has a synergistic effect, so that compared with a single nano component, the anti-aging and mechanical properties are more comprehensively improved; the compatibility is better, performance degradation caused by excessive agglomeration is avoided, the secondary anti-aging capability is remarkably improved, and the service life of the regenerated asphalt is prolonged.

The invention relates to the technical field of wastewater treatment, and provides a process for treating wastewater containing trimellitic acid, cobalt and manganese. Comprising the following steps: adding an extracting agent into wastewater containing trimellitic acid, cobalt and manganese for counter-current extraction, rectifying a water phase, adjusting the pH value, precipitating cobalt and manganese, carrying out electrolytic treatment, adding an extracting agent for counter-current extraction, combining extraction phases in the wastewater treatment process, and carrying out primary rectification, secondary rectification, crystallization and filtration treatment. And various substances generated in the process can be synchronously recovered, separated and reutilized. According to the technical scheme, the wastewater generated during preparation of 2, 6-NDA through oxidation of 2, 6-DIPN is treated, cobalt and manganese ions, trimellitic acid and other components in the wastewater are effectively recovered, meanwhile, an extracting agent and a treatment product used in the wastewater treatment process are recovered and recycled, and the content of 2, 6-NDA is greatly reduced. The raw material consumption and the wastewater treatment cost of 6, 6-NDA production are reduced, and excellent economic benefits are achieved.

The present invention provides a thermally conductive polyimide film with high elongation, a method for manufacturing the same, a metal laminate using the polyimide film, electrical and electronic equipment, and a flexible printed circuit board. [Solution] A thermally conductive polyimide film is used, comprising a polyimide resin (A), a filler (B), and an aliphatic ester compound (C) of pyromellitic acid or trimellitic acid, wherein the aliphatic ester compound (C) contains an aliphatic group having 4 to 12 carbon atoms, and the content of the filler (B) relative to the total volume of the thermally conductive polyimide film is 15% by volume or more.

The present invention relates to: a polyimide; and a resin composition comprising the polyimide and another resin. The polyimide comprises: as a diamine component, a diamine having a difluoromethoxy group; and as a tetracarboxylic acid dianhydride component, at least one tetracarboxylic acid dianhydride that is selected from the group consisting of a tetracarboxylic acid dianhydride having an ether bond, a tetracarboxylic acid dianhydride having a cardo structure, and a bis(trimellitic acid anhydride) ester. Examples of other resins that constitute the resin composition include acrylic resins and polyester resins.

The invention relates to the technical field of fine chemical synthesis, in particular to a synthesis method capable of effectively reducing the boiling point of trimethyl trimellitate. A reactor is included, a rectifying tower is arranged on one side of the reactor, a liquid spraying assembly is fixedly connected to the inner side of the rectifying tower, and a supporting assembly is arranged on the inner side of the rectifying tower; and fillers are arranged on the inner sides of the supporting assemblies. Through the arrangement of the premixing tank and the action of a stirring rod, trimethyl trimellitate and polyhydric alcohol can be premixed in the premixing tank before entering the rectifying tower, so that the trimethyl trimellitate and the polyhydric alcohol are more uniform and can be better added into the rectifying tower, and meanwhile, through the cooperation of a gear and a gear ring, the rectification efficiency is improved. According to the invention, the connecting rod can drive the stirring rod to rotate in the rotating process, so that the stirring rod has a better mixing effect on trimethyl trimellitate and polyol, azeotrope can be distributed more uniformly, and subsequent rectification quality can be guaranteed and separation efficiency can be improved.

This invention provides a method for producing spherical aggregates of nanosilver particles using a simple method. The produced spherical aggregates of nanosilver particles exhibit excellent dispersibility and handling properties, and exhibit conductivity upon sintering at low temperatures, making them suitable for use as conductive fillers. [Solution] A method for producing spherical aggregates of silver particles by adding one or more additives selected from the following group A to a silver compound solution and a reducing agent solution. Group A: Citric acid, citrate anhydride, citrate salt, trimellitic acid, trimellitic anhydride, trimellitic salt

The invention relates to a method for continuously crystallizing trimellitic anhydride into anhydride. Pressing the intermediate products trimellitic acid and acetic acid into a buffer intermediate kettle; the materials flow into a bottom feeding port of the first flash heat exchanger from the bottom, and acetic acid is removed through flash evaporation under the vacuum effect; the materials are further heated through a second flash heat exchanger, a small amount of residual acetic acid is further removed under the vacuum effect, and the materials are promoted to be preliminarily dehydrated into anhydride; the materials enter a third flash heat exchanger for further dehydration; the materials continue to enter a fourth flash heat exchanger, and the remaining small amount of trimellitic acid is further subjected to deep reaction; after the reaction is completed, the mixture enters a light component removal tower, by-products which are not subjected to the oxidation reaction completely are removed, and a trimellitic anhydride crude product is extracted from a tower kettle; the method has the advantages that the materials are continuously fed and heated in the acetic acid removal and anhydride dehydration processes, the energy consumption is low, the system efficiency is high, the acetic acid is continuously removed, the anhydride is further dehydrated, and the reaction efficiency is improved while the product quality is ensured.