Preparation and application method of catalyst for synthesizing triisononyl trimellitate
阅读说明：本技术 一种合成偏苯三酸三异壬酯催化剂的制备及应用方法 (Preparation and application method of catalyst for synthesizing triisononyl trimellitate ) 是由 曹正国 李江华 王福 陈佳佳 殷文慧 于 2021-01-07 设计创作，主要内容包括：本发明涉及有机化工技术领域内的一种合成偏苯三酸三异壬酯催化剂的制备方法,其先制备ZrO-2粉末,在将其将沉淀物在100-120℃下干燥8-16h后,研磨成粉,过100目筛；再制备HZSM-5氢型分子筛；然后将两者混合并于的磷酸溶液中浸泡,最后抽滤,焙烧,得到目标产物[PO4～(3-)/ZrO-2]-HZSM-5复合型超强酸催化剂固体。目标产物可作为催化剂用于合成偏苯三酸三异壬酯。其能缩短反应时间,避免对设备的腐蚀问题,以及提高反应的选择性,解决副产物多、难处理的问题。(The invention relates to a preparation method of a catalyst for synthesizing triisononyl trimellitate in the technical field of organic chemical industry, which firstly prepares ZrO 2 Powder, drying the precipitate at the temperature of 100-120 ℃ for 8-16h, grinding the dried precipitate into powder, and sieving the powder by a 100-mesh sieve; then preparing HZSM-5 hydrogen type molecular sieve; mixing the two, soaking in phosphoric acid solution, vacuum filtering, and calcining to obtain the target product [ PO4 ] 3‑ /ZrO 2 ]-HZSM-5 composite type super strongAn acid catalyst solid. The target product can be used as a catalyst for synthesizing triisononyl trimellitate. It can shorten reaction time, avoid corrosion to equipment, improve reaction selectivity and solve the problems of more by-products and difficult treatment.)
1. A preparation method of a catalyst for synthesizing triisononyl trimellitate is characterized by comprising the following steps:
(1) ZrOCl2∙8H2Dissolving O in deionized water, placing in an ice water bath, dropwise adding ammonia water with the mass fraction of 25% into the deionized water to precipitate the O, adjusting the pH to be =10, aging for 18-30h, performing suction filtration, and washing with deionized water for multiple times until no chloride ions exist in the filtrate;
(2) drying the precipitate at the temperature of 100-120 ℃ for 8-16h, grinding the precipitate into powder, and sieving the powder by a 100-mesh sieve;
(3) carrying out ion exchange on the ZSM-5 type molecular sieve by using a dilute hydrochloric acid solution with the concentration of 1.0-2.0mol/L, stirring for several hours at the temperature of 90-95 ℃ until the exchange degree reaches more than 97 percent, and obtaining the HZSM-5 hydrogen type molecular sieve;
(4) grinding HZSM-5 hydrogen type molecular sieve to pass through 100 mesh sieve, andmixing the precipitates sieved by the 100-mesh sieve in the step (2), soaking in a phosphoric acid solution with the concentration of 0.2-1.0mol/L for 8-16h according to the proportion of 12-18g/mL, carrying out suction filtration and roasting to obtain a target product [ PO4 ]3-/ZrO2]-HZSM-5 composite super acidic catalyst solid.
2. The method for preparing a catalyst for the synthesis of triisononyl trimellitate as defined in claim 1, wherein in step (1), ZrOCl is added2∙8H2ZrOCl obtained after O is dissolved in deionized water2The molar concentration of (b) is 0.3-0.8 mol/L.
3. The method for preparing the triisononyl trimellitate catalyst according to claim 1, wherein the weight ratio of the HZSM-5 hydrogen type molecular sieve to the precipitate in the step (4) is as follows: 1: (1-3.5).
4. The method for using the catalyst for synthesizing triisononyl trimellitate according to claims 1-3, characterized in that the catalyst is used as a catalyst for esterification of trimellitic anhydride and isononyl alcohol in an amount of 0.04-0.12% by weight of the sum of trimellitic anhydride and isononyl alcohol.
5. The application method of the catalyst for synthesizing triisononyl trimellitate is characterized by comprising the following steps of:
(1) esterification reaction: putting raw materials of trimellitic anhydride and isononyl alcohol into an esterification reaction kettle, heating to 122-156 ℃ under the conditions of nitrogen protection and uniform stirring, wherein the molar ratio of the trimellitic anhydride to the isononyl alcohol is 1: (3.2-4.0); after the trimellitic anhydride is completely dissolved in isononyl alcohol, the temperature is raised to 185 +/-5 ℃, and a catalyst is added, wherein the catalyst is [ PO4 ]3-/ZrO2]-HZSM-5 composite super acidic catalyst solid; keeping the temperature for reaction for 0.5-1h, and simultaneously separating water generated in the esterification process; continuously heating to 218-Measuring the acid value; when the acid value of the esterification liquid is more than 0.07 mg KOH/g, the constant temperature reflux is continuously carried out; when the acid value of the esterification liquid is measured to be less than or equal to 0.07 mg KOH/g, the esterification reaction is finished, and the next step is carried out;
(2) negative pressure dealcoholization: feeding the esterification solution at the bottom of the esterification reaction kettle into a dealcoholization tower for negative pressure dealcoholization, wherein the vacuum degree of the dealcoholization tower is 0.04-0.08Mpa, the dealcoholization time is 1.5-2.5h, and the dealcoholization temperature is 190 ℃;
(3) alkali washing and water washing: introducing nitrogen into the esterified solution after dealcoholization, and circulating the esterified solution by a heat exchanger at normal pressure to reduce the temperature of a reaction system to 75-105 ℃; adding a proper amount of sodium carbonate solution, and neutralizing to be neutral; then slowly adding distilled water for washing, standing for 0.4-0.6h, layering, and draining off the lower layer white flocculate;
(4) removing low-boiling-point substances: introducing nitrogen, heating to 190 ℃ at 160-; stopping vacuumizing after negative pressure air extraction, introducing nitrogen, stopping heating when the system is recovered to a normal pressure state, and cooling;
(5) adsorption and filtration: transferring the esterification liquid cooled to 70-90 ℃ into a filter, adsorbing and decoloring, and filtering to obtain the qualified triisononyl trimellitate.
Technical Field
The invention relates to a preparation method and an application method of an esterification reaction catalyst for synthesizing triisononyl trimellitate, belonging to the technical field of organic chemical industry.
Background
Plasticizers are substances which are added to polymeric systems to increase their plasticity, flexibility or swellability. Its main function is to weaken the secondary valence bond between polymer molecules, i.e. van der waals force, so that the mobility of polymer molecular chain is increased, and the crystallinity of polymer molecular chain is reduced, i.e. the plasticity of polymer is increased, and mainly the hardness, modulus, transformation temperature and embrittlement temperature of polymer are reduced, and the elongation, flexibility and flexibility of the polymer are raised.
Currently, scientists have developed a variety of promising plasticizers. Firstly, modifying a phthalate plasticizer; secondly, new varieties of plasticizers such as polyester, epoxide, citrate, castor oil, trimellitate, aliphatic dibasic acid ester and the like are developed.
Trimellitate catalysts are broadly classified into molecular sieves, titanates (tetraisopropyl titanate, tetrabutyl titanate, and a mixture of one or more thereof), titanium metal compounds, and composite compositions of tin metal compounds and other compounds. There has been little research on a catalyst for the synthesis of triisononyl trimellitate.
Chinese patent CN101973884A describes a method for synthesizing triisononyl trimellitate (TINTM for short). The method uses a sulfuric acid-free catalytic synthesis process, does not use the traditional sulfuric acid catalysis, but uses titanate as a catalyst, and has no pollution and good product quality.
The Chinese invention patent CN108117666A develops a method for synthesizing a high and low temperature resistant plasticizer triisononyl trimellitate. The method overcomes the defects that the existing common plasticizer has poor cold resistance, can crack, is damaged and the like at low temperature of wires, electric wires and cables for vehicles, and the like, and auxiliary materials are added in the processing process and are mixed by glycidyl ether, a leveling agent, a calcium/zinc stabilizer, a flame retardant system and the like, so that the performance of the TINTM is stronger at high and low temperatures.
One of the catalysts currently used in industrial production is a protonic acid catalyst, such as sulfuric acid. It has low cost and reaction temperature below 180 deg.c, but the catalyst has long catalytic time, serious corrosion to apparatus, oxidation, carbonization and other side reactions, and thus dark color and luster of product and difficult post-treatment. Another commonly used catalyst is titanate, which requires a long reaction time, is not recyclable, and is relatively expensive.
Disclosure of Invention
The invention aims to provide a preparation method and an application method of a catalyst for synthesizing triisononyl trimellitate, which can shorten the reaction time, avoid the corrosion problem to equipment, improve the selectivity of the reaction and solve the problems of more byproducts and difficult treatment.
The purpose of the invention is realized as follows:
1. a preparation method of a catalyst for synthesizing triisononyl trimellitate comprises the following steps:
(1) ZrOCl2∙8H2O is dissolved in deionized water, ZrOCl2The molar concentration of the mixed solution is 0.3-0.8mol/L, the formed solution is placed in an ice water bath, ammonia water with the mass fraction of 25% is dripped into the ice water bath to precipitate the solution, the pH is adjusted to be =10, the aging is carried out for 18-30h, the solution is filtered and washed for many times by deionized water until no chloride ion exists in the filtrate;
(2) drying the precipitate at the temperature of 100-120 ℃ for 8-16h, grinding the precipitate into powder, and sieving the powder by a 100-mesh sieve;
(3) carrying out ion exchange on the ZSM-5 type molecular sieve by using a dilute hydrochloric acid solution with the concentration of 1.0-2.0mol/L, stirring for several hours at the temperature of 90-95 ℃ until the exchange degree reaches more than 97 percent, and obtaining the HZSM-5 hydrogen type molecular sieve; the weight ratio of the HZSM-5 hydrogen type molecular sieve to the precipitate is as follows: 1: (1-3.5).
(4) Grinding the HZSM-5 hydrogen type molecular sieve, sieving with a 100-mesh sieve, mixing with the precipitate sieved with the 100-mesh sieve in the step (2), and adding phosphoric acid with the concentration of 0.2-1.0mol/L according to the proportion of 12-18g/mLSoaking in the solution for 8-16h, filtering, and calcining to obtain target product [ PO4 ]3-/ZrO2]-HZSM-5 composite super acidic catalyst solid.
In the step (4), the weight ratio of the HZSM-5 hydrogen type molecular sieve to the precipitate is as follows: 1: (1-3.5).
The target product [ PO43-/ZrO2]The solid-HZSM-5 composite super acidic catalyst is used as the catalyst for the esterification reaction of trimellitic anhydride and isononyl alcohol, and the dosage of the solid-HZSM-5 composite super acidic catalyst is 0.04 to 0.12 percent of the sum of the weight of trimellitic anhydride and isononyl alcohol.
The invention also discloses an application method of the catalyst for synthesizing triisononyl trimellitate, which comprises the following steps:
(1) esterification reaction: putting raw materials of trimellitic anhydride and isononyl alcohol into an esterification reaction kettle, heating to 122-156 ℃ under the conditions of nitrogen protection and uniform stirring, wherein the molar ratio of the trimellitic anhydride to the isononyl alcohol is 1: (3.2-4.0); after the trimellitic anhydride is completely dissolved in the isononyl alcohol, the temperature is raised to 185 +/-5 ℃, and a catalyst accounting for 0.04-0.12 percent of the total mass ratio of the materials is added, wherein the catalyst is [ PO4 ]3-/ZrO2]-HZSM-5 composite super acidic catalyst solid; keeping the temperature for reaction for 0.5-1h, and simultaneously separating water generated in the esterification process; continuously heating to 218-236 ℃, continuously carrying out constant-temperature reflux, continuously increasing the ester content in the esterification liquid in the reaction kettle, sampling from the bottom of the esterification reaction kettle after reacting for a period of time, and measuring the acid value; when the acid value of the esterification liquid is more than 0.07 mg KOH/g, the constant temperature reflux is continuously carried out; when the acid value of the esterification liquid is measured to be less than or equal to 0.07 mg KOH/g, the esterification reaction is finished, and the next step is carried out;
(2) negative pressure dealcoholization: feeding the esterification solution at the bottom of the esterification reaction kettle into a dealcoholization tower for negative pressure dealcoholization, wherein the vacuum degree of the dealcoholization tower is 0.04-0.08Mpa, the dealcoholization time is 1.5-2.5h, and the dealcoholization temperature is 190 ℃;
(3) alkali washing and water washing: introducing nitrogen into the esterified solution after dealcoholization, and circulating the esterified solution by a heat exchanger at normal pressure to reduce the temperature of a reaction system to 75-105 ℃; adding a proper amount of sodium carbonate solution, and neutralizing to be neutral; then slowly adding distilled water for washing, standing for 0.4-0.6h, layering, and draining off the lower layer white flocculate;
(4) removing low-boiling-point substances: introducing nitrogen, heating to 190 ℃ at 160-; stopping vacuumizing after negative pressure air extraction, introducing nitrogen, stopping heating when the system is recovered to a normal pressure state, and cooling;
(5) adsorption and filtration: transferring the esterification liquid cooled to 70-90 ℃ into a filter, adsorbing and decoloring, and filtering to obtain the qualified triisononyl trimellitate.
The invention has the beneficial effects that the used catalyst is a composite solid super acidic catalyst, and the HZSM-5 carrier has a large amount of pore structures, so that the coordination adsorption capacity of PO4^ 3-is increased, the acid centers on the surface of the catalyst are increased, and stronger acidity is expressed. When the load ratio reaches ZrO2When the percent is not larger than 50 percent, the activity of the catalyst is the highest, and the yield of the product is 98 percent at the highest. And the advantage of good stability due to the molecular sieve is that the ZrO compound passes through2The structure is still complete after the high temperature required for crystal form transformation. [ PO43-/ZrO2]the-HZSM-5 composite solid super acidic catalyst can not only improve the reaction activity of the catalyst, but also the quality of the triisononyl trimellitate product is high. The method has the advantages of simple process, easy operation and no pollution, does not corrode reaction equipment when being applied to esterification reaction at the later stage, improves the production rate of products, and has good economic and environmental feasibility.
Detailed Description
The first embodiment is as follows:
the preparation method of the esterification catalyst specifically comprises the following steps:
(1) weighing a certain amount of ZrOCl2▪8H2Dissolving O in deionized water to obtain ZrOCl2The molar concentration is 0.3mol/L, the solution is placed in an ice water bath, ammonia water with the mass fraction of 25% is dripped into the ice water bath to precipitate the solution, the pH is adjusted to be =10, the solution is aged for 24h, and the solution is filtered and washed by deionized water for many times until no chloride ion exists in the filtrate.
(2) Drying the precipitate at 110 deg.C for 12 hr, grinding, and sieving with 100 mesh sieveSieving, the precipitate component being ZrO2。
(3) And (3) carrying out ion exchange on the ZSM-5 type molecular sieve by using a dilute hydrochloric acid solution with the molar concentration of 2.0mol/L, stirring for several hours at the temperature of 90 ℃, and obtaining the HZSM-5 molecular sieve until the exchange degree reaches more than 97%.
(4) Grinding the HZSM-5 molecular sieve, sieving with a 100-mesh sieve, and mixing with the precipitate obtained in the step (2), wherein ZrO in the precipitate is240 wt% (ZrO) of2The total weight of the two components) and then soaking the mixture in phosphoric acid with the molar concentration of 0.2mol/L for 12 hours according to the proportion of 12g/mL, filtering and roasting to obtain [ PO4 ]3-/ZrO2]-HZSM-5 composite solid super acidic catalyst.
The [ PO4 ]3-/ZrO2]the-HZSM-5 composite solid super acidic catalyst is used for preparing triisononyl trimellitate and is used as a catalyst for esterification reaction of trimellitic anhydride and isononyl alcohol, and the dosage of the catalyst is 0.04-0.12 percent of the sum of the weight of trimellitic anhydride and isononyl alcohol.
The concrete application is as follows:
esterification reaction: putting raw materials of trimellitic anhydride and isononyl alcohol into an esterification reaction kettle, heating to 122 ℃ under the conditions of nitrogen protection and uniform stirring, wherein the molar ratio of the trimellitic anhydride to the isononyl alcohol is 1: 3.2; after the trimellitic anhydride is completely dissolved in the isononyl alcohol, the temperature is raised to 180 ℃, and a catalyst accounting for 0.04 percent of the total mass of the materials is added, wherein the catalyst is [ PO4 ]3-/ZrO2]-HZSM-5 composite super acidic catalyst solid; keeping the temperature for reaction for 0.5h, and simultaneously separating water generated in the esterification process; continuously heating to 218 ℃, continuously carrying out constant-temperature reflux, continuously increasing the ester content in the esterification liquid in the reaction kettle, sampling from the bottom of the esterification reaction kettle after reacting for a period of time, and measuring the acid value; when the acid value of the esterification liquid is more than 0.07 mgKOH/g, constant-temperature reflux is continuously carried out; when the acid value of the esterification liquid is measured to be less than or equal to 0.07 mg KOH/g, the esterification reaction is finished, and the next step is carried out;
(2) negative pressure dealcoholization: feeding the esterification solution at the bottom of the esterification reaction kettle into a dealcoholization tower for negative pressure dealcoholization, wherein the vacuum degree of the dealcoholization tower is 0.04Mpa, the dealcoholization time is 1.5h, and the dealcoholization temperature is 190 ℃;
(3) alkali washing and water washing: introducing nitrogen into the esterified solution after dealcoholization, and circulating the esterified solution by a heat exchanger at normal pressure to reduce the temperature of a reaction system to 75 ℃; adding a proper amount of sodium carbonate solution, and neutralizing to be neutral; then slowly adding distilled water for washing, standing for 0.4h, layering, and draining white flocculate at the lower layer;
(4) removing low-boiling-point substances: introducing nitrogen, heating to 160 ℃, vacuumizing to the vacuum degree of 0.04Mpa, removing low-boiling-point substances and residual isononyl alcohol in the reaction system under negative pressure, and exhausting for 1.5h under negative pressure; stopping vacuumizing after negative pressure air extraction, introducing nitrogen, stopping heating when the system is recovered to a normal pressure state, and cooling;
(5) adsorption and filtration: transferring the esterification liquid cooled to 70 ℃ into a filter, adsorbing and decoloring, and filtering to obtain qualified triisononyl trimellitate with the product yield of 96%.
Example two:
the preparation method of the esterification catalyst specifically comprises the following steps:
(1) weighing a certain amount of ZrOCl2▪8H2Dissolving O in deionized water, ZrOCl2The mixture is placed in an ice water bath with the molar concentration of 0.5mol/L, ammonia water with the mass fraction of 25% is dripped into the mixture to precipitate the mixture, the pH is adjusted to be =10, the mixture is aged for 18h, and the mixture is filtered and washed by deionized water for many times until no chloride ion exists in the filtrate.
(2) Drying the precipitate at 110 deg.C for 12 hr, grinding, and sieving with 100 mesh sieve to obtain ZrO2And (3) powder.
(3) And (3) carrying out ion exchange on the ZSM-5 type molecular sieve by using a dilute hydrochloric acid solution with the molar concentration of 1.5mol/L, stirring for several hours at the temperature of 92 ℃ until the exchange degree reaches more than 97 percent, and thus obtaining the HZSM-5 molecular sieve.
(4) Grinding the HZSM-5 molecular sieve to pass through a 100-mesh sieve, and mixing with the ZrO obtained in the step (2)2According to 50 wt% each (ZrO)2The total weight of the two components) is mixed, then the mixture is soaked in phosphoric acid with the molar concentration of 0.6mol/L for 12 hours according to the proportion of 15g/mL, and then the mixture is filtered and roasted to obtain [ PO4 ]3-/ZrO2]-HZSM-5 composite solid super acidic catalyst.
The following applies:
esterification reaction: putting raw materials of trimellitic anhydride and isononyl alcohol into an esterification reaction kettle, heating to 160 ℃ under the conditions of nitrogen protection and uniform stirring, wherein the molar ratio of the trimellitic anhydride to the isononyl alcohol is 1: 3.5; after the trimellitic anhydride is completely dissolved in the isononyl alcohol, the temperature is raised to 185 ℃, and a catalyst accounting for 0.08 percent of the total mass of the materials is added, wherein the catalyst is [ PO4 ]3-/ZrO2]-HZSM-5 composite super acidic catalyst solid; keeping the temperature for reaction for 0.7h, and simultaneously separating water generated in the esterification process; continuously heating to 225 ℃, continuously carrying out constant-temperature reflux, continuously increasing the ester content in the esterification liquid in the reaction kettle, sampling from the bottom of the esterification reaction kettle after reacting for a period of time, and measuring the acid value; when the acid value of the esterification liquid is more than 0.07 mgKOH/g, constant-temperature reflux is continuously carried out; when the acid value of the esterification liquid is determined to be 0.06 mg KOH/g, the esterification reaction is finished, and the next step is carried out;
(2) negative pressure dealcoholization: feeding the esterification solution at the bottom of the esterification reaction kettle into a dealcoholization tower for negative pressure dealcoholization, wherein the vacuum degree of the dealcoholization tower is 0.08Mpa, the dealcoholization time is 2.5 hours, and the dealcoholization temperature is 180 ℃;
(3) alkali washing and water washing: introducing nitrogen into the esterified solution after dealcoholization, and circulating the esterified solution by a heat exchanger at normal pressure to reduce the temperature of the reaction system to 90 ℃; adding a proper amount of sodium carbonate solution, and neutralizing to be neutral; then slowly adding distilled water for washing, standing for 0.5h, layering, and draining white flocculate at the lower layer;
(4) removing low-boiling-point substances: introducing nitrogen, heating to 175 ℃, vacuumizing to the vacuum degree of 0.06Mpa, removing low-boiling-point substances and residual isononyl alcohol in the reaction system under negative pressure, and exhausting for 2.0h under negative pressure; stopping vacuumizing after negative pressure air extraction, introducing nitrogen, stopping heating when the system is recovered to a normal pressure state, and cooling;
(5) adsorption and filtration: transferring the esterification liquid cooled to 80 ℃ into a filter, adsorbing, decoloring and filtering to obtain qualified triisononyl trimellitate with the product yield of 98%.
Example three:
the preparation method of the esterification catalyst specifically comprises the following steps:
(1) weighing a certain amount of ZrOCl2▪8H2Dissolving O in deionized water with the molar concentration of 0.8mol/L, placing in an ice water bath, dropwise adding ammonia water with the mass fraction of 25% into the ice water bath to precipitate, adjusting the pH to be =10, aging for 30h, performing suction filtration, and washing with deionized water for multiple times until no chloride ions exist in the filtrate.
(2) Drying the precipitate at 110 deg.C for 12 hr, grinding, and sieving with 100 mesh sieve to obtain ZrO2And (3) powder.
(3) And (3) carrying out ion exchange on the ZSM-5 type molecular sieve by using a dilute hydrochloric acid solution with the molar concentration of 1.0mol/L, stirring for several hours at the temperature of 95 ℃ until the exchange degree reaches more than 97 percent, and thus obtaining the HZSM-5 molecular sieve.
(4) Grinding HZSM-5 molecular sieve, sieving with 100 mesh sieve, and mixing with ZrO2Mixing the powders, wherein ZrO2In an amount of 60wt% (ZrO)2The total weight of the two components) and then soaking the mixture in phosphoric acid with the molar concentration of 1.0mol/L for 12 hours according to the proportion of 18g/mL, filtering and roasting to obtain [ PO4 ]3-/ZrO2]-HZSM-5 composite solid super acidic catalyst.
The following applies:
esterification reaction: putting raw materials of trimellitic anhydride and isononyl alcohol into an esterification reaction kettle, heating to 156 ℃ under the conditions of nitrogen protection and uniform stirring, wherein the molar ratio of the trimellitic anhydride to the isononyl alcohol is 1: 4.0; after the trimellitic anhydride is completely dissolved in the isononyl alcohol, the temperature is raised to 190 ℃, and a catalyst accounting for 0.12 percent of the total mass of the materials is added, wherein the catalyst is [ PO4 ]3-/ZrO2]-HZSM-5 composite super acidic catalyst solid; keeping the temperature for reaction for 1.0h, and simultaneously separating water generated in the esterification process; continuously heating to 236 ℃, continuously carrying out constant-temperature reflux, continuously increasing the ester content in the esterification liquid in the reaction kettle, sampling from the bottom of the esterification reaction kettle after reacting for a period of time, and measuring the acid value; when the acid value of the esterification liquid is more than 0.07 mgKOH/g, constant-temperature reflux is continuously carried out; when the acid value of the esterification solution is determined to be 0.065 mg KOH/g, the esterification reaction is finished, and the next step is carried out;
(2) negative pressure dealcoholization: feeding the esterification solution at the bottom of the esterification reaction kettle into a dealcoholization tower for negative pressure dealcoholization, wherein the vacuum degree of the dealcoholization tower is 0.06Mpa, the dealcoholization time is 2.0h, and the dealcoholization temperature is 170 ℃;
(3) alkali washing and water washing: introducing nitrogen into the esterified solution after dealcoholization, and circulating the esterified solution by a heat exchanger at normal pressure to reduce the temperature of the reaction system to 105 ℃; adding a proper amount of sodium carbonate solution, and neutralizing to be neutral; then slowly adding distilled water for washing, standing for 0.6h, layering, and draining white flocculate at the lower layer;
(4) removing low-boiling-point substances: introducing nitrogen, heating to 190 ℃, vacuumizing to the vacuum degree of 0.08Mpa, removing low-boiling-point substances and residual isononyl alcohol in the reaction system under negative pressure, and extracting for 2.5 hours under negative pressure; stopping vacuumizing after negative pressure air extraction, introducing nitrogen, stopping heating when the system is recovered to a normal pressure state, and cooling;
(5) adsorption and filtration: transferring the esterification liquid cooled to 90 ℃ into a filter, adsorbing and decoloring, and filtering to obtain qualified triisononyl trimellitate with the product yield of 97%.
The present invention is not limited to the above-mentioned embodiments, and based on the technical solutions disclosed in the present invention, those skilled in the art can make some substitutions and modifications to some technical features without creative efforts according to the disclosed technical contents, and these substitutions and modifications are all within the protection scope of the present invention.
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