CN117326930A - Process for producing pyromellitic acid - Google Patents
Process for producing pyromellitic acid Download PDFInfo
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- CN117326930A CN117326930A CN202210731372.6A CN202210731372A CN117326930A CN 117326930 A CN117326930 A CN 117326930A CN 202210731372 A CN202210731372 A CN 202210731372A CN 117326930 A CN117326930 A CN 117326930A
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- pyromellitic acid
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- durene
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- alkali metal
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- CYIDZMCFTVVTJO-UHFFFAOYSA-N pyromellitic acid Chemical compound OC(=O)C1=CC(C(O)=O)=C(C(O)=O)C=C1C(O)=O CYIDZMCFTVVTJO-UHFFFAOYSA-N 0.000 title claims abstract description 128
- 238000000034 method Methods 0.000 title claims abstract description 15
- 238000006243 chemical reaction Methods 0.000 claims abstract description 44
- SQNZJJAZBFDUTD-UHFFFAOYSA-N durene Chemical compound CC1=CC(C)=C(C)C=C1C SQNZJJAZBFDUTD-UHFFFAOYSA-N 0.000 claims abstract description 44
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims abstract description 33
- 239000007789 gas Substances 0.000 claims abstract description 17
- 238000007254 oxidation reaction Methods 0.000 claims abstract description 15
- 238000004519 manufacturing process Methods 0.000 claims abstract description 14
- 229910052783 alkali metal Inorganic materials 0.000 claims abstract description 11
- 229910052799 carbon Inorganic materials 0.000 claims abstract description 10
- 239000003054 catalyst Substances 0.000 claims abstract description 10
- 239000002086 nanomaterial Substances 0.000 claims abstract description 9
- -1 alkali metal persulfate Chemical class 0.000 claims abstract description 8
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims abstract description 4
- 239000001301 oxygen Substances 0.000 claims abstract description 4
- 229910052760 oxygen Inorganic materials 0.000 claims abstract description 4
- QTBSBXVTEAMEQO-UHFFFAOYSA-N Acetic acid Chemical compound CC(O)=O QTBSBXVTEAMEQO-UHFFFAOYSA-N 0.000 claims description 39
- 239000012425 OXONE® Substances 0.000 claims description 24
- HJKYXKSLRZKNSI-UHFFFAOYSA-I pentapotassium;hydrogen sulfate;oxido sulfate;sulfuric acid Chemical compound [K+].[K+].[K+].[K+].[K+].OS([O-])(=O)=O.[O-]S([O-])(=O)=O.OS(=O)(=O)O[O-].OS(=O)(=O)O[O-] HJKYXKSLRZKNSI-UHFFFAOYSA-I 0.000 claims description 24
- 229910021393 carbon nanotube Inorganic materials 0.000 claims description 21
- 239000002041 carbon nanotube Substances 0.000 claims description 21
- 239000002904 solvent Substances 0.000 claims description 17
- 239000007791 liquid phase Substances 0.000 claims description 5
- 239000002134 carbon nanofiber Substances 0.000 claims description 4
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical class C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 claims description 4
- 238000001816 cooling Methods 0.000 claims description 3
- 238000002425 crystallisation Methods 0.000 claims description 3
- 230000008025 crystallization Effects 0.000 claims description 3
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 2
- 239000011541 reaction mixture Substances 0.000 claims 1
- 230000007797 corrosion Effects 0.000 abstract description 7
- 238000005260 corrosion Methods 0.000 abstract description 7
- 229910052723 transition metal Inorganic materials 0.000 abstract description 4
- 239000007787 solid Substances 0.000 description 22
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 17
- 239000000047 product Substances 0.000 description 14
- 230000000052 comparative effect Effects 0.000 description 13
- 239000012535 impurity Substances 0.000 description 12
- 239000000706 filtrate Substances 0.000 description 11
- 229910001873 dinitrogen Inorganic materials 0.000 description 7
- 239000004642 Polyimide Substances 0.000 description 6
- 229920001721 polyimide Polymers 0.000 description 6
- 229910052757 nitrogen Inorganic materials 0.000 description 5
- ANSXAPJVJOKRDJ-UHFFFAOYSA-N furo[3,4-f][2]benzofuran-1,3,5,7-tetrone Chemical compound C1=C2C(=O)OC(=O)C2=CC2=C1C(=O)OC2=O ANSXAPJVJOKRDJ-UHFFFAOYSA-N 0.000 description 3
- 239000000463 material Substances 0.000 description 3
- 230000003647 oxidation Effects 0.000 description 3
- 150000003624 transition metals Chemical class 0.000 description 3
- WKBOTKDWSSQWDR-UHFFFAOYSA-N Bromine atom Chemical compound [Br] WKBOTKDWSSQWDR-UHFFFAOYSA-N 0.000 description 2
- GDTBXPJZTBHREO-UHFFFAOYSA-N bromine Substances BrBr GDTBXPJZTBHREO-UHFFFAOYSA-N 0.000 description 2
- 229910052794 bromium Inorganic materials 0.000 description 2
- 239000012071 phase Substances 0.000 description 2
- OTYBMLCTZGSZBG-UHFFFAOYSA-L potassium sulfate Chemical compound [K+].[K+].[O-]S([O-])(=O)=O OTYBMLCTZGSZBG-UHFFFAOYSA-L 0.000 description 2
- 229910052939 potassium sulfate Inorganic materials 0.000 description 2
- 235000011151 potassium sulphates Nutrition 0.000 description 2
- 229910001428 transition metal ion Inorganic materials 0.000 description 2
- 239000002699 waste material Substances 0.000 description 2
- WGSMMQXDEYYZTB-UHFFFAOYSA-N 1,2,4,5-tetramethylbenzene Chemical compound CC1=CC(C)=C(C)C=C1C.CC1=CC(C)=C(C)C=C1C WGSMMQXDEYYZTB-UHFFFAOYSA-N 0.000 description 1
- VLDPXPPHXDGHEW-UHFFFAOYSA-N 1-chloro-2-dichlorophosphoryloxybenzene Chemical compound ClC1=CC=CC=C1OP(Cl)(Cl)=O VLDPXPPHXDGHEW-UHFFFAOYSA-N 0.000 description 1
- JTNCEQNHURODLX-UHFFFAOYSA-N 2-phenylethanimidamide Chemical compound NC(=N)CC1=CC=CC=C1 JTNCEQNHURODLX-UHFFFAOYSA-N 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 239000006227 byproduct Substances 0.000 description 1
- 230000003197 catalytic effect Effects 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 230000018044 dehydration Effects 0.000 description 1
- 238000006297 dehydration reaction Methods 0.000 description 1
- 238000001914 filtration Methods 0.000 description 1
- 239000002815 homogeneous catalyst Substances 0.000 description 1
- 150000002500 ions Chemical group 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 239000004973 liquid crystal related substance Substances 0.000 description 1
- 239000012528 membrane Substances 0.000 description 1
- 238000004377 microelectronic Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 239000002861 polymer material Substances 0.000 description 1
- 229910000343 potassium bisulfate Inorganic materials 0.000 description 1
- USHAGKDGDHPEEY-UHFFFAOYSA-L potassium persulfate Chemical compound [K+].[K+].[O-]S(=O)(=O)OOS([O-])(=O)=O USHAGKDGDHPEEY-UHFFFAOYSA-L 0.000 description 1
- 239000002243 precursor Substances 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 238000000746 purification Methods 0.000 description 1
- 230000001105 regulatory effect Effects 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 238000001308 synthesis method Methods 0.000 description 1
- 238000003786 synthesis reaction Methods 0.000 description 1
- 230000002194 synthesizing effect Effects 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C51/00—Preparation of carboxylic acids or their salts, halides or anhydrides
- C07C51/16—Preparation of carboxylic acids or their salts, halides or anhydrides by oxidation
- C07C51/21—Preparation of carboxylic acids or their salts, halides or anhydrides by oxidation with molecular oxygen
- C07C51/255—Preparation of carboxylic acids or their salts, halides or anhydrides by oxidation with molecular oxygen of compounds containing six-membered aromatic rings without ring-splitting
- C07C51/265—Preparation of carboxylic acids or their salts, halides or anhydrides by oxidation with molecular oxygen of compounds containing six-membered aromatic rings without ring-splitting having alkyl side chains which are oxidised to carboxyl groups
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C51/00—Preparation of carboxylic acids or their salts, halides or anhydrides
- C07C51/42—Separation; Purification; Stabilisation; Use of additives
- C07C51/43—Separation; Purification; Stabilisation; Use of additives by change of the physical state, e.g. crystallisation
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Engineering & Computer Science (AREA)
- Oil, Petroleum & Natural Gas (AREA)
- Crystallography & Structural Chemistry (AREA)
- Heterocyclic Carbon Compounds Containing A Hetero Ring Having Oxygen Or Sulfur (AREA)
Abstract
The invention discloses a method for producing pyromellitic acid. The method comprises the following steps: in the presence of oxygen-containing gas, durene contacts with a catalyst to perform oxidation reaction to obtain pyromellitic acid; the catalyst includes a carbon nanomaterial and an alkali metal persulfate. The pyromellitic acid prepared by the method has the advantages of no transition metal salt residue, no corrosion in reaction and high pyromellitic acid yield.
Description
Technical Field
The invention belongs to the field of pyromellitic acid, and particularly relates to a production method of pyromellitic acid.
Background
Pyromellitic acid (1, 2,4, 5-pyromellitic acid, PMA) is an important organic intermediate and is widely applied to the preparation of various high-end fine materials. The product of the dehydration of pyromellitic acid is pyromellitic dianhydride (1, 2,4, 5-pyromellitic dianhydride, PMDA), which is one of important precursors for synthesizing Polyimide (PI). Polyimide is a special polymer material and has the advantages of wide application temperature, chemical corrosion resistance, high strength and the like. The dupont company in 1961 has first introduced a commodity of polyimide, and since then polyimide has been widely used as a special engineering material in the fields of aviation, aerospace, microelectronics, nano-scale, liquid crystal, separation membrane, laser and the like. Therefore, the green production of pyromellitic acid is significant for the efficient synthesis of polyimide.
The PMA synthesis method generally comprises the oxidation of durene (1, 2,4, 5-tetramethylbenzene), and is divided into a gas phase method and a liquid phase method. Although the gas phase method can directly generate PMDA, the reaction process has higher temperature, a plurality of byproducts and lower product purity, and the PMDA still needs to be hydrolyzed into PMA for further purification; the catalyst adopted by the liquid phase oxidation is generally transition metal/bromine, has higher corrosiveness and higher danger, and is easy to cause corrosion of devices and larger in pollution of waste liquid.
US5041633 discloses a method for preparing pyromellitic acid by catalytic oxidation of pyromellitic acid with Co-Mn-Br homogeneous catalyst. However, the problem of corrosion of the transition metal ions remained in the product and the device is still not solved, and the yield of PMA prepared by the method is still to be improved.
In the method for preparing pyromellitic acid in the prior art, the problems of easy transition metal ion residue, corrosion of a reaction device and low pyromellitic acid yield exist at different degrees. The further development and research of the production method of pyromellitic acid have great significance.
Disclosure of Invention
Aiming at the defects in the prior art, the invention provides a method for producing pyromellitic acid. The pyromellitic acid prepared by the method has the advantages of no transition metal salt residue, no corrosion in reaction and high pyromellitic acid yield.
The invention provides a method for producing pyromellitic acid, which comprises the following steps:
in the presence of oxygen-containing gas, durene contacts with a catalyst to perform oxidation reaction to obtain pyromellitic acid; preferably, the catalyst comprises a carbon nanomaterial and an alkali metal persulfate.
According to the invention, the oxygen-containing gas is preferably air.
According to the invention, the alkali metal peroxodisulfate comprises potassium monopersulfate. The potassium monopersulfate is a trisulfate formed by combining potassium persulfate, potassium bisulfate and potassium sulfate, and has a molecular formula of 2KHSO 5 ·KHSO 4 ·K 2 SO 4 Abbreviated PMS.
According to the present invention, the carbon nanomaterial includes at least one of carbon nanotubes and carbon nanofibers.
According to the invention, the mass ratio of alkali metal persulfate to carbon nanomaterial in the catalyst is 0.5 to 10, preferably 4 to 7.
According to the invention, the mass ratio of alkali metal peroxodisulfate to durene in the catalyst is from 0.05 to 0.5, preferably from 0.1 to 0.2.
According to the invention, the temperature of the oxidation reaction is 120 to 270 ℃, preferably 180 to 220 ℃.
According to the invention, the pressure of the oxidation reaction is between 10 and 30bar. Preferably, the pressure of the oxidation reaction is regulated by the introduction of nitrogen.
According to the invention, the time of the oxidation reaction is 60 to 150 minutes.
According to the present invention, it is preferable to add the carbon nanomaterial to durene first and then add the alkali metal persulfate.
According to the present invention, it is preferable that cooling crystallization is performed after the completion of the reaction, and the temperature of the cooling crystallization is 10 to 60 ℃.
According to the invention, the oxidation reaction is a liquid phase reaction. Preferably, durene is dispersed in the solvent. More preferably, the solvent comprises at least one of acetic acid and water. Further preferably, the mass ratio of the solvent to durene is 2 to 10.
Compared with the prior art, the invention has the main beneficial effects that:
in the method for producing the pyromellitic acid, the transition metal and the bromine catalyst do not participate in the reaction, the pyromellitic acid prepared by the method has the advantages of no transition metal residue, no corrosion in the reaction, little three wastes in the whole reaction process, high pyromellitic acid yield and little impurity.
Detailed Description
The following describes the technical scheme of the present invention in detail by referring to examples.
In the present invention, the inner diameter of the carbon nanotube is 5 to 10nm in each example.
Example 1
100 g of durene (98 wt.%) was added to 400 g of acetic acid solvent and stirred uniformly, 2.5g of carbon nanotubes were added, and the temperature was gradually increased to 140℃in a stirred tank over 50min with nitrogen gas being introduced, and the pressure in the tank was maintained at 20bar. Then 10g of Potassium Monopersulfate (PMS) was added while switching the gas to air at 10L/min, the stirred tank was again warmed to 200℃and the pressure was increased to 30bar, and the reaction was continued for 2 hours. The reaction solution is filtered while hot to remove solid impurities and carbon nanotubes. The filtrate was cooled to crystallize at 15 ℃, and then the filtered solid was dried for 6 hours at 100 ℃ in an oven to obtain pyromellitic acid (PMA) product with a conversion rate of 92.3mol.% of pyromellitic acid and a PMA selectivity of 91.5mol.%.
For the convenience of comparative examples, the experimental results are shown in Table 1.
Example 2
100 g of durene (98 wt.%) was added to 400 g of acetic acid solvent and stirred uniformly, 10.0g of carbon nanotubes were added, and the temperature was gradually increased to 140℃in a stirred tank over 50min with nitrogen gas being introduced, and the pressure in the tank was maintained at 20bar. Then 10g of Potassium Monopersulfate (PMS) was added while switching the gas to air at 10L/min, the stirred tank was again warmed to 200℃and the pressure was increased to 30bar, and the reaction was continued for 2 hours. The reaction solution is filtered while hot to remove solid impurities and carbon nanotubes. The filtrate was cooled to crystallize at 15 ℃, and then the filtered solid was dried for 6 hours at 100 ℃ in an oven to obtain pyromellitic acid (PMA) product with a 92.2mol.% pyromellitic conversion rate and a PMA selectivity of 82.1mol.%.
For the convenience of comparative examples, the experimental results are shown in Table 1.
Example 3
100 g of durene (98 wt.%) was added to 400 g of acetic acid solvent and stirred uniformly, then 1.5g of carbon nanotubes were added, and the temperature was gradually increased to 140℃in a stirred tank over 50min with nitrogen gas being introduced, and the pressure in the tank was maintained at 20bar. Then 10g of Potassium Monopersulfate (PMS) was added while switching the gas to air at 10L/min, the stirred tank was again warmed to 200℃and the pressure was increased to 30bar, and the reaction was continued for 2 hours. The reaction solution is filtered while hot to remove solid impurities and carbon nanotubes. The filtrate was cooled to crystallize at 15 ℃, and then the filtered solid was dried for 6 hours at 100 ℃ in an oven to obtain pyromellitic acid (PMA) product with 85.2mol.% pyromellitic conversion and 90.6mol.% PMA selectivity.
For the convenience of comparative examples, the experimental results are shown in Table 1.
Example 4
100 g of durene (98 wt.%) was added to 400 g of acetic acid solvent and stirred uniformly, then 1.25g of carbon nanotubes were added, and the temperature was gradually increased to 140℃in a stirred tank over 50min with nitrogen gas being introduced, and the pressure in the tank was maintained at 20bar. Then 10g of Potassium Monopersulfate (PMS) was added while switching the gas to air at 10L/min, the stirred tank was again warmed to 200℃and the pressure was increased to 30bar, and the reaction was continued for 2 hours. The reaction solution is filtered while hot to remove solid impurities and carbon nanotubes. The filtrate was cooled to crystallize at 15 ℃, and then the filtered solid was dried for 6 hours at 100 ℃ in an oven to obtain pyromellitic acid (PMA) product with a pyromellitic conversion of 83.1mol.% and a PMA selectivity of 91.0mol.%.
For the convenience of comparative examples, the experimental results are shown in Table 1.
Example 5
100 g of durene (98 wt.%) was added to 400 g of acetic acid solvent and stirred uniformly, 2.5g of carbon nanofibers were added, the temperature was gradually increased to 140℃in a stirred tank over 50min with nitrogen being introduced, and the pressure in the tank was maintained at 20bar. Then 10g of Potassium Monopersulfate (PMS) was added while switching the gas to air at 10L/min, the stirred tank was again warmed to 200℃and the pressure was increased to 30bar, and the reaction was continued for 2 hours. Filtering the reaction solution while the reaction solution is hot, and removing solid impurities and carbon nanofibers. The filtrate was cooled to crystallize at 15 ℃, and then the filtered solid was dried for 6 hours at 100 ℃ in an oven to obtain pyromellitic acid (PMA) product with 90.5mol.% pyromellitic conversion and 89.7mol.% PMA selectivity.
For the convenience of comparative examples, the experimental results are shown in Table 1.
Example 6
100 g of durene (98 wt.%) is added into 400 g of acetic acid solvent and stirred uniformly, 5g of carbon nanotubes are added, the temperature is gradually increased to 140 ℃ in a stirred tank within 50min, nitrogen is introduced, and the pressure in the tank is kept at 20bar. Subsequently, 20g of Potassium Monopersulfate (PMS) was added while switching the gas to air at 10L/min, the stirred tank was again warmed to 200℃and the pressure was increased to 30bar, and the reaction was continued for 2 hours. The reaction solution is filtered while hot to remove solid impurities and carbon nanotubes. The filtrate was cooled to crystallize at 15 ℃, and then the filtered solid was dried for 6 hours at 100 ℃ in an oven to obtain pyromellitic acid (PMA) product with a pyromellitic conversion of 95.2mol.% and a PMA selectivity of 85.8mol.%.
For the convenience of comparative examples, the experimental results are shown in Table 1.
Example 7
100 g of durene (98 wt.%) is added into 400 g of acetic acid solvent and stirred uniformly, 5g of carbon nanotubes are added, the temperature is gradually increased to 140 ℃ in a stirred tank within 50min, nitrogen is introduced, and the pressure in the tank is kept at 20bar. Then 5g of Potassium Monopersulfate (PMS) was added while switching the gas to air at 10L/min, the stirred tank was again warmed to 200℃and the pressure to 30bar and reacted for 2h. The reaction solution is filtered while hot to remove solid impurities and carbon nanotubes. The filtrate was cooled to crystallize at 15 ℃, and then the filtered solid was dried for 6 hours at 100 ℃ in an oven to obtain pyromellitic acid (PMA) product with 80.2mol.% pyromellitic conversion and 90.1mol.% PMA selectivity.
For the convenience of comparative examples, the experimental results are shown in Table 1.
Example 8
100 g of durene (98 wt.%) was added to 400 g of acetic acid solvent and stirred uniformly, 2.5g of carbon nanotubes were added, and the temperature was gradually increased to 140℃in a stirred tank over 50min with nitrogen gas being introduced, and the pressure in the tank was maintained at 20bar. Then 10g of Potassium Monopersulfate (PMS) was added while switching the gas to air at 10L/min, the stirred tank was again warmed to 150℃and the pressure was increased to 30bar, and the reaction was continued for 2 hours. The reaction solution is filtered while hot to remove solid impurities and carbon nanotubes. The filtrate was cooled to crystallize at 15 ℃, and then the filtered solid was dried for 6 hours at 100 ℃ in an oven to obtain pyromellitic acid (PMA) product with a pyromellitic conversion of 82.1mol.% and a PMA selectivity of 80.3mol.%.
For the convenience of comparative examples, the experimental results are shown in Table 1.
Example 9
100 g of durene (98 wt.%) was added to 400 g of acetic acid solvent and stirred uniformly, 2.5g of carbon nanotubes were added, and the temperature was gradually increased to 140℃in a stirred tank over 50min with nitrogen gas being introduced, and the pressure in the tank was maintained at 20bar. Then 10g of Potassium Monopersulfate (PMS) was added while switching the gas to air at 10L/min, the stirred tank was again warmed to 260℃and the pressure was increased to 30bar and reacted for 2 hours. The reaction solution is filtered while hot to remove solid impurities and carbon nanotubes. The filtrate was cooled to crystallize at 15 ℃, and then the filtered solid was dried for 6 hours at 100 ℃ in an oven to obtain pyromellitic acid (PMA) product with a conversion rate of 91.3mol.% and a PMA selectivity of 78.2mol.%.
For the convenience of comparative examples, the experimental results are shown in Table 1.
Comparative example 1
100 g of durene (98 wt.%) was added to 400 g of acetic acid solvent and stirred uniformly, 2.5g of activated carbon was added, the temperature was gradually increased to 140℃in a stirred tank over 50min with nitrogen being introduced, and the pressure in the tank was maintained at 20bar. Then 10g of Potassium Monopersulfate (PMS) was added while switching the gas to air at 10L/min, the stirred tank was again warmed to 200℃and the pressure was increased to 30bar, and the reaction was continued for 2 hours. The reaction solution is filtered while hot to remove solid impurities and active carbon. The filtrate was cooled to crystallize at 15 ℃, and then the filtered solid was dried for 6 hours at 100 ℃ in an oven to obtain pyromellitic acid (PMA) product with a pyromellitic conversion of 65.2mol.% and a PMA selectivity of 51.3mol.%.
For the convenience of comparative examples, the experimental results are shown in Table 1.
Comparative example 2
100 g of durene (98 wt.%) was added to 400 g of acetic acid solvent and stirred uniformly, 2.5g of carbon nanotubes were added, and the temperature was gradually increased to 140℃in a stirred tank over 50min with nitrogen gas being introduced, and the pressure in the tank was maintained at 20bar. Then 10g of potassium sulfate is added, air is introduced at 10L/min while switching gas, the temperature of the stirred tank is raised to 200 ℃ again, the pressure is raised to 30bar, and the reaction is carried out for 2h. The reaction solution is filtered while hot to remove solid impurities and carbon nanotubes. The filtrate was cooled to crystallize at 15 ℃, and then the filtered solid was dried for 6 hours at 100 ℃ in an oven to obtain pyromellitic acid (PMA) product with 35.5mol.% pyromellitic conversion and 14.2mol.% PMA selectivity.
For the convenience of comparative examples, the experimental results are shown in Table 1.
TABLE 1
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 (10)
1. A method for producing pyromellitic acid, comprising the steps of: in the presence of oxygen-containing gas, durene contacts with a catalyst to perform oxidation reaction to obtain pyromellitic acid; preferably, the catalyst comprises a carbon nanomaterial and an alkali metal persulfate.
2. The production method according to claim 1, wherein the alkali metal peroxodisulfate comprises potassium monopersulfate.
3. The method of claim 1, wherein the carbon nanomaterial comprises at least one of carbon nanotubes and carbon nanofibers.
4. The production method according to claim 1, wherein the mass ratio of the alkali metal persulfate to the carbon nanomaterial is 0.5 to 10, preferably 4 to 7.
5. The production method according to claim 1, wherein the mass ratio of the alkali metal persulfate to durene is from 0.05 to 0.5, preferably from 0.1 to 0.2.
6. The production method according to claim 1, characterized in that the temperature of the oxidation reaction is 120-270 ℃, preferably 180-220 ℃.
7. The production method according to claim 1, wherein the pressure of the oxidation reaction is 10 to 30bar.
8. The method according to claim 1, wherein the time of the oxidation reaction is 60 to 150 minutes.
9. The production method according to claim 1, wherein the oxidation reaction is a liquid phase reaction;
preferably, durene is dispersed in a solvent for liquid phase reaction;
more preferably, the solvent comprises at least one of acetic acid and water;
further preferably, the mass ratio of the solvent to durene is 2-10;
and/or adding carbon nanomaterial to durene, and then adding alkali metal persulfate.
10. The process according to claim 1, wherein after the completion of the reaction, the reaction mixture is subjected to cooling crystallization at a temperature of 10 to 60 ℃.
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| Country | Link |
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