CN117683039B - Method for producing pyromellitic anhydride by pyromellitic acid dehydration process - Google Patents

Method for producing pyromellitic anhydride by pyromellitic acid dehydration process

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CN117683039B
CN117683039B CN202211080516.2A CN202211080516A CN117683039B CN 117683039 B CN117683039 B CN 117683039B CN 202211080516 A CN202211080516 A CN 202211080516A CN 117683039 B CN117683039 B CN 117683039B
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pyromellitic
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diphenyl ether
temperature
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CN117683039A (en
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罗伟
肖忠斌
李建
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China Petroleum and Chemical Corp
Sinopec Shanghai Research Institute of Petrochemical Technology
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China Petroleum and Chemical Corp
Sinopec Shanghai Research Institute of Petrochemical Technology
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    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07D—HETEROCYCLIC COMPOUNDS
    • C07D493/00—Heterocyclic compounds containing oxygen atoms as the only ring hetero atoms in the condensed system
    • C07D493/02—Heterocyclic compounds containing oxygen atoms as the only ring hetero atoms in the condensed system in which the condensed system contains two hetero rings
    • C07D493/04—Ortho-condensed systems

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  • Heterocyclic Carbon Compounds Containing A Hetero Ring Having Oxygen Or Sulfur (AREA)

Abstract

本发明提出了一种均苯四甲酸脱水工艺生产均苯四甲酸酐的方法，属于有机化合物合成技术领域。所述方法包括：(1)将均苯四甲酸溶于有机溶剂，加热脱水；(2)冷却结晶，分离得均苯四甲酸二酐；所述有机溶剂包括二苯醚和氢化三联苯。本发明采用二苯醚和氢化三联苯的混合物，扩大了低温操作窗口，而且比单独采用二苯醚或单独采用氢化三联苯为溶剂时得到了更好的PMDA收率和PMDA纯度，解决了现有技术中低温结晶时容易造成体系粘稠、温度操作窗口窄、操作不便等问题。This invention proposes a method for producing pyromellitic dianhydride from pyromellitic tetracarboxylic acid through dehydration, belonging to the field of organic compound synthesis technology. The method includes: (1) dissolving pyromellitic tetracarboxylic acid in an organic solvent and heating to dehydrate it; (2) cooling and crystallizing to separate pyromellitic dianhydride; the organic solvent includes diphenyl ether and hydrogenated terphenyl. This invention uses a mixture of diphenyl ether and hydrogenated terphenyl, expanding the low-temperature operating window, and achieving better PMDA yield and purity than when using diphenyl ether or hydrogenated terphenyl alone as the solvent. It solves the problems of viscous system, narrow temperature operating window, and inconvenient operation during low-temperature crystallization in existing technologies.

Description

Method for producing pyromellitic anhydride by pyromellitic acid dehydration process
Technical Field
The invention relates to a method for refining pyromellitic anhydride by dehydrating pyromellitic acid, belonging to the technical field of organic compound synthesis.
Background
Pyromellitic anhydride (PMDA) is an important organic chemical raw material, and is mainly used for producing polyimide, epoxy resin, polyester resin, plasticizer and the like, and can also be used as an adhesive, a surfactant, a metal corrosion inhibitor, a leather tanning agent, a high-temperature lubricant, fuel and the like.
At present, the technological process of pyromellitic dianhydride is mainly divided into two types, namely gas-phase oxidation and liquid-phase oxidation. The vapor phase oxidation mainly uses durene as a raw material, V 2O5 as a catalyst and directly produces pyromellitic dianhydride by high-temperature vapor phase oxidation. Although the vapor phase method can generate pyromellitic dianhydride in one step, the cycle conversion rate is low, the product has more impurities, the pyromellitic dianhydride can be used as an intermediate after hydrolysis and purification, the reaction process temperature is too high, and the energy consumption is high. The liquid phase method is to oxidize durene in acetic acid solvent to produce durene tetracarboxylic acid with Co-Mn-Br catalyst system, and then to dewater and refine durene tetracarboxylic dianhydride with high reaction temperature.
In the prior art, when the pyromellitic anhydride is refined by adopting a pyromellitic acid dehydration process, the solvent is diphenyl ether alone, so that the problems of viscous system, even diphenyl ether crystallization and the like are easily caused during low-temperature crystallization, the temperature operation window of the low-temperature crystallization is narrow, the operation is inconvenient, or the acetic anhydride and the pyromellitic acid are adopted for mixed heating dehydration, but the consumption of the acetic anhydride is overlarge, the acetic anhydride is difficult to recover, and the cost is overlarge.
Disclosure of Invention
In order to solve the problems in the prior art, the invention provides a method for refining pyromellitic anhydride by dehydrating pyromellitic acid, which has good PMDA yield and PMDA purity.
According to one aspect of the present invention, there is provided a method for producing pyromellitic anhydride by dehydration of pyromellitic acid, the method comprising:
(1) Heating and dehydrating a mixed solution containing pyromellitic acid and an organic solvent to obtain a mixture;
(2) Cooling and crystallizing the mixture, and separating to obtain a crystalline substance containing pyromellitic anhydride;
the organic solvent comprises diphenyl ether and hydrogenated terphenyl.
Optionally, the mass ratio of hydrogenated terphenyl to diphenyl ether in the organic solvent is 4-15.
In the above technical solution, as a non-limiting example, the mass ratio of hydrogenated terphenyl to diphenyl ether in the organic solvent is 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, or any value between any two points.
Optionally, the mass ratio of pyromellitic acid to the organic solvent in the mixed solution is 0.1-0.4.
In the above technical solution, as a non-limiting example, the mass ratio of pyromellitic acid to the organic solvent is 0.15, 0.2, 0.25, 0.3, 0.35, or any value between any two points.
Optionally, the temperature of the heating dehydration is 150-270 ℃.
In the above technical solution, the temperature of the heating dehydration is 160 ℃, 170 ℃,180 ℃, 190 ℃, 200 ℃, 210 ℃, 220 ℃, 230 ℃, 240 ℃, 250 ℃, 260 ℃ or any value between any two points, which are taken as non-limiting examples.
Optionally, the time for heating and dehydrating is 1-6 hours.
In the above technical solution, as a non-limiting example, the time of the heating and dehydrating is 1.5h, 2h, 2.5h, 3h, 3.5h, 4h, 4.5h, 5h, 5.5h, or any value between any two points.
Optionally, the heated dewatering is divided into a first stage heated dewatering and a second stage heated dewatering.
Optionally, the temperature of the first section of heating dehydration is 150-210 ℃ and the time is 1-3 h.
Optionally, the temperature of the second section of heating dehydration is 220-270 ℃ and the time is 1-3 h.
In the above technical scheme, as a non-limiting example, the first stage heating and dehydrating time is 1.5h, 2h, 2.5h, 3h or any value between any two points, and the first stage heating and dehydrating temperature is 160 ℃, 170 ℃, 180 ℃, 190 ℃, 200 ℃ and 210 ℃ or any value between any two points;
the second stage heating and dehydrating time is 1.5h, 2h, 2.5h and 3h or any value between any two points, and the second stage heating and dehydrating temperature is 220 ℃, 230 ℃, 240 ℃, 250 ℃, 260 ℃ and 265 ℃ or any value between any two points.
Optionally, the cooling crystallization temperature is 5-35 ℃.
In the above technical solution, as a non-limiting example, the temperature of the cooling crystallization is 10 ℃,12 ℃, 15 ℃,18 ℃, 20 ℃, 22 ℃, 25 ℃, 30 ℃ or any value between any two points.
Optionally, the cooling crystallization time is 2-10 h.
In the above technical solution, as a non-limiting example, the cooling crystallization time is 3h, 4h, 5h, 6h, 7h, 8h, 9h, or any value between any two points.
Optionally, the purity of the pyromellitic acid is 80wt.% to 100wt.%.
The yield of the pyromellitic anhydride is more than 90.0mol percent, preferably more than 95.0mol percent, and the purity of the pyromellitic anhydride in the crystalline substance is more than 91.0 percent, preferably 99.8 percent.
The invention has the following beneficial effects:
In the prior art, diphenyl ether is used as a solvent, but when the diphenyl ether is singly used, the system is easy to be thick and even the diphenyl ether is easy to crystallize at low temperature, the temperature operation window of the low temperature crystallization is narrow, and the operation is inconvenient. The invention adopts the mixture of diphenyl ether and hydrogenated terphenyl, expands the low-temperature operation window, and obtains better PMDA yield and PMDA purity than the method which adopts diphenyl ether or hydrogenated terphenyl as solvent.
Detailed Description
The invention is further illustrated below in connection with specific examples, which are not to be construed as limiting the invention in any way.
In the present application,
Y (yield, mol%) = (C pyromellitic dianhydride ( Powder (D) )-C pyromellitic dianhydride ( Initially, the method comprises ))/C pyromellitic acid ( Initially, the method comprises )
C pyromellitic dianhydride ( Powder (D) ), the content of pyromellitic dianhydride at the end of the reaction, and mol;
c pyromellitic dianhydride ( Initially, the method comprises ), reacting to obtain the content and mol of pyromellitic dianhydride;
C pyromellitic acid ( Initially, the method comprises ) the content of pyromellitic acid and mol at the beginning of the reaction.
The purity parameter of pyromellitic dianhydride is measured by liquid chromatography (GC 780) to compare the integral area S with the pyromellitic dianhydride standard (99.9 wt%;
purity% = S ( Test sample )/S( Pyromellitic dianhydride standard sample ).
Example 1
100G of pyromellitic acid (90 wt.%) and 50g of diphenyl ether are stirred uniformly, and 400g of hydrogenated terphenyl is added to obtain a mixed solution. Subsequently, the mixed solution was heated to 200℃with continuous stirring at a heating rate of 10℃/min at 30℃for 2 hours to obtain a mixture. The insoluble material in the mixture was then filtered off while hot, and the filtrate was retained. And heating the filtrate to 240 ℃, keeping the temperature for 2 hours, cooling to 30 ℃, standing for 6 hours to generate solid crystals, filtering the solid crystals, washing twice with acetic anhydride, and drying in vacuum at 60 ℃ for 3 hours to obtain the pyromellitic dianhydride (PMDA) product. The pyromellitic dianhydride (PMDA) product yield was 96.6 mol% with a purity of 99.8%.
For comparison, the experimental results are presented in Table 1.
Example 2
100G of pyromellitic acid (90 wt.%) and 50g of diphenyl ether are stirred uniformly, and 400g of hydrogenated terphenyl is added to obtain a mixed solution. Subsequently, the mixed solution was heated to 200℃with continuous stirring at a heating rate of 10℃/min at 30℃for 2 hours to obtain a mixture. The insoluble material in the mixture was then filtered off while hot, and the filtrate was retained. And heating the filtrate to 240 ℃, keeping the temperature for 2 hours, cooling to 20 ℃, standing for 6 hours to generate solid crystals, filtering the solid crystals, washing twice with acetic anhydride, and drying in vacuum at 60 ℃ for 3 hours to obtain the pyromellitic dianhydride (PMDA) product. The yield of pyromellitic dianhydride (PMDA) was 90.5 mol% and the purity was 91.2% for comparison and the experimental results are shown in table 1.
Example 3
100G of pyromellitic acid (90 wt.%) and 40g of diphenyl ether are stirred uniformly, and 410g of hydrogenated terphenyl is added to obtain a mixed solution. Subsequently, the mixed solution was heated to 200℃with continuous stirring at a heating rate of 10℃/min at 30℃for 2 hours to obtain a mixture. The insoluble material in the mixture was then filtered off while hot, and the filtrate was retained. And heating the filtrate to 240 ℃, keeping the temperature for 2 hours, cooling to 30 ℃, standing for 6 hours to generate solid crystals, filtering the solid crystals, washing twice with acetic anhydride, and drying in vacuum at 60 ℃ for 3 hours to obtain the pyromellitic dianhydride (PMDA) product. The pyromellitic dianhydride (PMDA) product yield was 94.4 mol% with a purity of 95.7%.
For comparison, the experimental results are presented in Table 1.
Example 4
100G of pyromellitic acid (90 wt.%) and 70g of diphenyl ether are stirred uniformly, and 380g of hydrogenated terphenyl is added to obtain a mixed solution. Subsequently, the mixed solution was heated to 200℃with continuous stirring at a heating rate of 10℃/min at 30℃for 2 hours to obtain a mixture. The insoluble material in the mixture was then filtered off while hot, and the filtrate was retained. And heating the filtrate to 240 ℃, keeping the temperature for 2 hours, cooling to 30 ℃, standing for 6 hours to generate solid crystals, filtering the solid crystals, washing twice with acetic anhydride, and drying in vacuum at 60 ℃ for 3 hours to obtain the pyromellitic dianhydride (PMDA) product. The pyromellitic dianhydride (PMDA) product yield was 92.5 mol% with a purity of 91.9%.
For comparison, the experimental results are presented in Table 1.
Example 5
100G of pyromellitic acid (90 wt.%) and 50g of diphenyl ether are stirred uniformly, and 400g of hydrogenated terphenyl is added to obtain a mixed solution. Subsequently, the mixed solution was heated to 200℃with continuous stirring at a heating rate of 10℃/min at 30℃for 2 hours to obtain a mixture. The insoluble material in the mixture was then filtered off while hot, and the filtrate was retained. And after keeping the temperature for 2 hours, cooling to 30 ℃, standing for 6 hours to generate solid crystals, filtering out the solid crystals, washing twice with acetic anhydride, and drying in vacuum at 60 ℃ for 3 hours to obtain the pyromellitic dianhydride (PMDA) product. The pyromellitic dianhydride (PMDA) product yield was 82.3 mol% with a purity of 90.6%.
For comparison, the experimental results are presented in Table 1.
Example 6
100G of pyromellitic acid (90 wt.%) and 50g of diphenyl ether are stirred uniformly, and 400g of hydrogenated terphenyl is added to obtain a mixed solution. Subsequently, the mixed solution was heated to 200℃with continuous stirring at a heating rate of 10℃/min at 30℃for 2 hours to obtain a mixture. The insoluble material in the mixture was then filtered off while hot, and the filtrate was retained. And heating the filtrate to 260 ℃, keeping the temperature for 2 hours, cooling to 30 ℃, standing for 6 hours to generate solid crystals, filtering the solid crystals, washing twice with acetic anhydride, and drying in vacuum at 60 ℃ for 3 hours to obtain the pyromellitic dianhydride (PMDA) product. The pyromellitic dianhydride (PMDA) product yield was 95.2 mol% with a purity of 98.9%.
Example 7
100G of pyromellitic acid (90 wt.%) and 70g of diphenyl ether are stirred uniformly, 560g of hydrogenated terphenyl is added, and a mixed solution is obtained. Subsequently, the mixed solution was heated to 200℃with continuous stirring at a heating rate of 10℃/min at 30℃for 2 hours to obtain a mixture. The insoluble material in the mixture was then filtered off while hot, and the filtrate was retained. And heating the filtrate to 240 ℃, keeping the temperature for 2 hours, cooling to 30 ℃, standing for 6 hours to generate solid crystals, filtering the solid crystals, washing twice with acetic anhydride, and drying in vacuum at 60 ℃ for 3 hours to obtain the pyromellitic dianhydride (PMDA) product. The pyromellitic dianhydride (PMDA) product yield was 95.0 mol% with a purity of 97.7%.
For comparison, the experimental results are presented in Table 1.
Example 8
100G of pyromellitic acid (90 wt.%) and 30g of diphenyl ether are stirred uniformly, 240g of hydrogenated terphenyl is added, and a mixed solution is obtained. Subsequently, the mixed solution was heated to 200℃with continuous stirring at a heating rate of 10℃/min at 30℃for 2 hours to obtain a mixture. The insoluble material in the mixture was then filtered off while hot, and the filtrate was retained. And heating the filtrate to 240 ℃, keeping the temperature for 2 hours, cooling to 30 ℃, standing for 6 hours to generate solid crystals, filtering the solid crystals, washing twice with acetic anhydride, and drying in vacuum at 60 ℃ for 3 hours to obtain the pyromellitic dianhydride (PMDA) product. The pyromellitic dianhydride (PMDA) product yield was 90.3 mol% with a purity of 94.1%.
For comparison, the experimental results are presented in Table 1.
Comparative example 1
100G of pyromellitic acid (90 wt.%) was added with 450g of hydrogenated terphenyl to obtain a mixed solution. Subsequently, the mixed solution was heated to 200℃with continuous stirring at a heating rate of 10℃/min at 30℃for 2 hours to obtain a mixture. The insoluble material in the mixture was then filtered off while hot, and the filtrate was retained. And heating the filtrate to 240 ℃, keeping the temperature for 2 hours, cooling to 30 ℃, standing for 6 hours to generate solid crystals, filtering the solid crystals, washing twice with acetic anhydride, and drying in vacuum at 60 ℃ for 3 hours to obtain the pyromellitic dianhydride (PMDA) product. The pyromellitic dianhydride (PMDA) product yield was 40.1 mol% with a purity of 64.3%.
For comparison, the experimental results are presented in Table 1.
Comparative example 2
100G of pyromellitic acid (90 wt.%) and 450g of diphenyl ether are uniformly stirred to obtain a mixed solution. Subsequently, the mixed solution was heated to 200℃with continuous stirring at a heating rate of 10℃/min at 30℃for 2 hours to obtain a mixture. The insoluble material in the mixture was then filtered off while hot, and the filtrate was retained. And heating the filtrate to 240 ℃, keeping the temperature for 2 hours, cooling to 30 ℃, standing for 6 hours to generate solid crystals, filtering the solid crystals, washing twice with acetic anhydride, and drying in vacuum at 60 ℃ for 3 hours to obtain the pyromellitic dianhydride (PMDA) product. The pyromellitic dianhydride (PMDA) product yield was 80.4 mol% with a purity of 83.9%.
For comparison, the experimental results are presented in Table 1.
Comparative example 3
100G of pyromellitic acid (90 wt.%) and 450g of diphenyl ether are uniformly stirred to obtain a mixed solution. Subsequently, the mixed solution was heated to 200℃with continuous stirring at a heating rate of 10℃/min at 30℃for 2 hours to obtain a mixture. The insoluble material in the mixture was then filtered off while hot, and the filtrate was retained. The filtrate was then warmed to 240 ℃ and held for 2 hours, cooled to 20 ℃ and the liquid mixture was gradually viscous until solidified, failing to complete the crystallization operation.
For comparison, the experimental results are presented in Table 1.
Table 1.
Any numerical value recited in this disclosure includes all values incremented by one unit from the lowest value to the highest value if there is only a two unit interval between any lowest value and any highest value. For example, if the amount of one component, or the value of a process variable such as temperature, pressure, time, etc., is stated to be 50-90, it means that values of 51-89, 52-88, and 69-71, and 70-71 are specifically recited in this specification. For non-integer values, 0.1, 0.01, 0.001 or 0.0001 units may be considered as appropriate. This is only a few examples of the specific designations. In a similar manner, all possible combinations of values between the lowest value and the highest value enumerated are to be considered to be disclosed.
It should be noted that the above-described embodiments are only for explaining the present invention and do not constitute any limitation of the present invention. The invention has been described with reference to exemplary embodiments, but it is understood that the words which have been used are words of description and illustration, rather than words of limitation. Modifications may be made to the invention as defined in the appended claims, and the invention may be modified without departing from the scope and spirit of the invention. Although the invention is described herein with reference to particular means, materials and embodiments, the invention is not intended to be limited to the particulars disclosed herein, as the invention extends to all other means and applications which perform the same function.

Claims (13)

1.均苯四甲酸脱水生产均苯四甲酸酐的方法，其特征在于，所述方法包括：1. A method for producing pyromellitic anhydride by dehydrating pyromellitic tetracarboxylic acid, characterized in that the method comprises: （1）将含有均苯四甲酸和有机溶剂的混合溶液，加热脱水得混合物；(1) A mixture containing pyromellitic acid and an organic solvent is heated and dehydrated to obtain a mixture; （2）将所述混合物冷却结晶，分离，得到含有均苯四甲酸酐的晶状物；(2) The mixture is cooled and crystallized, and separated to obtain a crystalline substance containing pyromellitic anhydride; 所述有机溶剂包括二苯醚和氢化三联苯；The organic solvents include diphenyl ether and hydrogenated terphenyl; 所述有机溶剂中氢化三联苯与二苯醚的质量比为4~15；The mass ratio of hydrogenated terphenyl to diphenyl ether in the organic solvent is 4-15; 所述冷却结晶的温度为5~35℃。The cooling crystallization temperature is 5~35℃. 2.根据权利要求1所述的方法，其特征在于，所述有机溶剂中氢化三联苯与二苯醚的质量比为5~12。2. The method according to claim 1, wherein the mass ratio of hydrogenated terphenyl to diphenyl ether in the organic solvent is 5-12. 3.根据权利要求1所述的方法，其特征在于，所述有机溶剂中氢化三联苯与二苯醚的质量比为8~12。3. The method according to claim 1, wherein the mass ratio of hydrogenated terphenyl to diphenyl ether in the organic solvent is 8-12. 4.根据权利要求1所述的方法，其特征在于，所述混合溶液中均苯四甲酸与有机溶剂的质量比为0.1~0.4。4. The method according to claim 1, wherein the mass ratio of pyromellitic acid to organic solvent in the mixed solution is 0.1 to 0.4. 5.根据权利要求1所述的方法，其特征在于，所述加热脱水的温度为150~270℃；5. The method according to claim 1, wherein the temperature for heating and dehydration is 150~270℃; 和/或，所述加热脱水的时间为1~6h。And/or, the heating and dehydration time is 1 to 6 hours. 6.根据权利要求1所述的方法，其特征在于，所述加热脱水分为第一段加热脱水和第二段加热脱水。6. The method according to claim 1, wherein the heating and dehydration is divided into a first stage of heating and dehydration and a second stage of heating and dehydration. 7.根据权利要求6所述的方法，其特征在于，所述第一段加热脱水的温度为150~210℃，时间为1~3h；7. The method according to claim 6, wherein the temperature of the first stage of heating and dehydration is 150~210℃ and the time is 1~3h; 和/或，所述第二段加热脱水的温度为220~270℃，时间为1~3h。And/or, the temperature of the second stage of heating and dehydration is 220~270℃, and the time is 1~3h. 8.根据权利要求1所述的方法，其特征在于，所述冷却结晶的温度为20~35℃。8. The method according to claim 1, wherein the cooling crystallization temperature is 20~35℃. 9.根据权利要求1所述的方法，其特征在于，所述冷却结晶的温度为25~35℃。9. The method according to claim 1, wherein the cooling crystallization temperature is 25~35℃. 10.根据权利要求1所述的方法，其特征在于，所述冷却结晶的时间为2~10h。10. The method according to claim 1, wherein the cooling and crystallization time is 2 to 10 hours. 11.根据权利要求1-10中任一项所述的方法，其特征在于，所述均苯四甲酸的纯度为80wt.%~100wt.%。11. The method according to any one of claims 1-10, wherein the purity of the pyromellitic acid is 80 wt.% to 100 wt.%. 12.根据权利要求1-10中任一项所述的方法，其特征在于，所述均苯四甲酸酐的收率大于90.0mol.%；所述晶状物中均苯四甲酸酐的纯度大于91.0重量%。12. The method according to any one of claims 1-10, characterized in that the yield of the pyromellitic anhydride is greater than 90.0 mol.%; and the purity of the pyromellitic anhydride in the crystals is greater than 91.0 wt%. 13.根据权利要求12所述的方法，其特征在于，所述均苯四甲酸酐的收率大于95.0mol.%；和/或，所述晶状物中均苯四甲酸酐的纯度大于99.8重量%。13. The method according to claim 12, wherein the yield of the pyromellitic anhydride is greater than 95.0 mol.%; and/or the purity of the pyromellitic anhydride in the crystals is greater than 99.8% by weight.
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