Disclosure of Invention
The invention aims to solve the technical problem that the content of aldehyde intermediates in the preparation of aromatic carboxylic acid by the oxidation of substituted aromatic hydrocarbon is high in the prior art, and provides a method for preparing aromatic carboxylic acid by adopting ionic liquid.
In order to solve the problems, the invention adopts the following technical scheme:
the method for preparing aromatic carboxylic acid by oxidizing substituted aromatic hydrocarbon comprises the following steps:
(1) Placing a catalyst, a solvent, ammonium salt and imidazole ionic liquid into a reaction kettle;
(2) Adding substituted aromatic hydrocarbon (heated to a molten state if the substituted aromatic hydrocarbon is solid at normal temperature) into the reaction kettle by adopting a high-pressure feed pump, and introducing air to react;
(3) And after the feeding of the iso-substituted aromatic hydrocarbon is completed, continuing to react for 0.5-3 hours to obtain a crude aromatic carboxylic acid mixture.
According to the invention, the ammonium salt and the imidazole ionic liquid are added into the solution, so that the content of aldehyde intermediates in the crude aromatic carboxylic acid is effectively reduced.
In the above technical solution, the solvent in step (1) is one or more mixtures of lower aliphatic carboxylic acids.
In the above technical scheme, the catalyst in the step (1) is a compound containing Co2+、Mn2+、Br-.
In the above technical scheme, in the catalyst in step (1), the mass concentration of the cobalt-based catalyst in the solution is 500-8000 ppm.
In the technical scheme, in the catalyst in the step (1), the Mn/Co molar ratio is 0.5-10.
In the technical scheme, in the catalyst in the step (1), the molar ratio of Br/(Co+Mn) is 1-10.
In the above technical scheme, co is preferably used in the form of cobalt acetate, mn is preferably used in the form of manganese acetate, br is preferably used in the form of hydrobromic acid, and for convenience, cobalt acetate is calculated as Co (OAc)2·4H2 O, manganese acetate is calculated as Mn (OAc)2·4H2 O, and hydrobromic acid is calculated as HBr (48 wt% H2 O).
In the above technical scheme, the ammonium salt in the step (1) is one or a mixture of more of ammonium acetate, ammonium sulfate and ammonium chloride.
In the above technical scheme, the ionic liquid in the step (1) is an imidazole ionic liquid, and mainly includes but is not limited to 1-butyl-3-methylimidazole bromide, 1-ethyl-3-methylimidazole acetate, 1-butyl-3-methylimidazole tetrafluoroborate and the like.
In the technical scheme, the reaction temperature is 150-250 ℃.
In the technical scheme, the reaction pressure is 1-4 MPa, and the pressure is gauge pressure.
In the technical scheme, the mass ratio of the substituted aromatic hydrocarbon added into the kettle to the solvent is 1:3-1:25.
In the above technical scheme, the substituted aromatic hydrocarbon in the step (2) refers to benzene, naphthalene or aromatic compound-like substance having more than one substituted alkyl group (or functional group having an oxidized methyl group). Mainly comprises, but is not limited to, o-xylene, m-xylene, p-xylene, 1,2, 4-trimethylbenzene, 1,3, 5-trimethylbenzene, 1,2,4, 5-tetramethylbenzene, dimethyl-substituted biphenyl, 2, 6-dimethylnaphthalene, 2, 6-diethylnaphthalene, 2, 6-diisopropylnaphthalene, 2, 7-dimethylnaphthalene, 2, 3-dimethylnaphthalene, 2-methyl-6-acetylnaphthalene, 5-hydroxymethylfurfural, and the like.
In the technical scheme, the influence of the feeding rate of the substituted aromatic hydrocarbon in the step (2) on the oxidation effect is very remarkable, and although the high feeding rate can improve the yield of the aromatic carboxylic acid and reduce the possibility of deep oxidation, the obtained aromatic carboxylic acid has lower purity, and the incompletely oxidized aldehyde intermediate in the product has more content and is not beneficial to subsequent purification treatment. The mass airspeed of the substituted aromatic hydrocarbon is 0.01-0.5 min-1.
The product of the invention is cooled, decompressed and separated, the crude product is washed by acetic acid and distilled water in turn after centrifugal separation, and then is dried, and is analyzed by high performance liquid chromatography after being dissolved by dimethyl sulfoxide.
The invention has the technical key that the aldehyde intermediate generated in the reaction process is converted into soluble ammonium salt by adding ammonium salt and imidazole ionic liquid, so that the ammonium salt of the aldehyde intermediate can fully react in the reaction process, and the content of the aldehyde intermediate in the product is reduced.
Detailed Description
[ Example 1 ]
The example uses paraxylene as a raw material:
(1) 2.12g Co(OAc)2·4H2O、6.26g Mn(OAc)2·4H2O、11.48g HBr（48wt%H2O）、8.48g NH4(OAc)2 g and 3816g of acetic acid are mixed and added into a 5L titanium reaction kettle;
(2) Firstly, exhausting air in the reaction kettle by using argon, then pressurizing to 1.5MPa, and regulating a back pressure valve behind a condensing pipe to keep the pressure in the reaction kettle stable;
(3) Stirring and heating, when the temperature reaches 200 ℃, introducing high-purity air at a rate of 20L/min until the pressure reaches 2.5MPa, and then adding 424g of paraxylene into a reaction kettle at a rate of 4.89g/min for reaction;
(4) After the paraxylene feeding is finished, maintaining the reaction temperature at 200 ℃ and the reaction pressure at 2.5MPa for continuous reaction for 2 hours;
(5) After the completion of the reaction, the crude terephthalic acid-containing mixture was filtered and washed with 80 ℃ acetic acid and 80 ℃ distilled water in this order, with the amounts of acetic acid and distilled water being 500g. Measuring the content of aldehyde intermediates by adopting high performance liquid chromatography after drying;
The content of p-carboxybenzaldehyde was found to be 434ppm by analytical calculation. For ease of illustration and comparison, catalyst compositions, reaction conditions, and analytical results are listed in the table.
[ Example 2 ]
The example uses paraxylene as a raw material:
(1) 2.12g Co(OAc)2·4H2O、6.26g Mn(OAc)2·4H2O、11.48g HBr（48wt%H2O）、21.2g 1- butyl-3-methylimidazole bromide and 3816g acetic acid are mixed and added into a 5L titanium reaction kettle;
(2) Firstly, exhausting air in the reaction kettle by using argon, then pressurizing to 1.5MPa, and regulating a back pressure valve behind a condensing pipe to keep the pressure in the reaction kettle stable;
(3) Stirring and heating, when the temperature reaches 200 ℃, introducing high-purity air at a rate of 20L/min until the pressure reaches 2.5MPa, and then adding 424g of paraxylene into a reaction kettle at a rate of 4.89g/min for reaction;
(4) After the paraxylene feeding is finished, maintaining the reaction temperature at 200 ℃ and the reaction pressure at 2.5MPa for continuous reaction for 2 hours;
(5) After the completion of the reaction, the crude terephthalic acid-containing mixture was filtered and washed with 80 ℃ acetic acid and 80 ℃ distilled water in this order, with the amounts of acetic acid and distilled water being 500g. Measuring the content of aldehyde intermediates by adopting high performance liquid chromatography after drying;
The content of p-carboxybenzaldehyde was calculated by analysis to be 1684ppm. For ease of illustration and comparison, catalyst compositions, reaction conditions, and analytical results are listed in the table.
[ Example 3 ]
The example uses paraxylene as a raw material:
(1) 2.12g Co(OAc)2·4H2O、6.26g Mn(OAc)2·4H2O、11.48g HBr（48wt%H2O）、8.48g NH4(OAc)2、21.2g 1- butyl-3-methylimidazole bromide and 3816g acetic acid are mixed and added into a 5L titanium reaction kettle;
(2) Firstly, exhausting air in the reaction kettle by using argon, then pressurizing to 1.5MPa, and regulating a back pressure valve behind a condensing pipe to keep the pressure in the reaction kettle stable;
(3) Stirring and heating, when the temperature reaches 200 ℃, introducing high-purity air at a rate of 20L/min until the pressure reaches 2.5MPa, and then adding 424g of paraxylene into a reaction kettle at a rate of 4.89g/min for reaction;
(4) After the paraxylene feeding is finished, maintaining the reaction temperature at 200 ℃ and the reaction pressure at 2.5MPa for continuous reaction for 2 hours;
(5) After the completion of the reaction, the crude terephthalic acid-containing mixture was filtered and washed with 80 ℃ acetic acid and 80 ℃ distilled water in this order, with the amounts of acetic acid and distilled water being 500g. Measuring the content of aldehyde intermediates by adopting high performance liquid chromatography after drying;
The content of p-carboxybenzaldehyde was found to be 186ppm by analytical calculation. For ease of illustration and comparison, catalyst compositions, reaction conditions, and analytical results are listed in the table.
[ Example 4 ]
The example uses paraxylene as a raw material:
(1) 2.12g Co(OAc)2·4H2O、6.26g Mn(OAc)2·4H2O、11.48g HBr（48wt%H2O）、21.2g NH4(OAc)2、21.2g 1- butyl-3-methylimidazole bromide and 3816g acetic acid are mixed and added into a 5L titanium reaction kettle;
(2) Firstly, exhausting air in the reaction kettle by using argon, then pressurizing to 1.5MPa, and regulating a back pressure valve behind a condensing pipe to keep the pressure in the reaction kettle stable;
(3) Stirring and heating, when the temperature reaches 200 ℃, introducing high-purity air at a rate of 20L/min until the pressure reaches 2.5MPa, and then adding 424g of paraxylene into a reaction kettle at a rate of 4.89g/min for reaction;
(4) After the paraxylene feeding is finished, maintaining the reaction temperature at 200 ℃ and the reaction pressure at 2.5MPa for continuous reaction for 2 hours;
(5) After the completion of the reaction, the crude terephthalic acid-containing mixture was filtered and washed with 80 ℃ acetic acid and 80 ℃ distilled water in this order, with the amounts of acetic acid and distilled water being 500g. Measuring the content of aldehyde intermediates by adopting high performance liquid chromatography after drying;
The content of p-carboxybenzaldehyde was found to be 156ppm by analytical calculation. For ease of illustration and comparison, catalyst compositions, reaction conditions, and analytical results are listed in the table.
[ Example 5]
The example uses paraxylene as a raw material:
(1) 2.12g Co(OAc)2·4H2O、6.26g Mn(OAc)2·4H2O、11.48g HBr（48wt%H2O）、21.2g NH4(OAc)2、21.2g 1- ethyl-3-methylimidazole bromide and 3816g of acetic acid are mixed and added into a 5L titanium reaction kettle;
(2) Firstly, exhausting air in the reaction kettle by using argon, then pressurizing to 1.5MPa, and regulating a back pressure valve behind a condensing pipe to keep the pressure in the reaction kettle stable;
(3) Stirring and heating, when the temperature reaches 200 ℃, introducing high-purity air at a rate of 20L/min until the pressure reaches 2.5MPa, and then adding 424g of paraxylene into a reaction kettle at a rate of 4.89g/min for reaction;
(4) After the paraxylene feeding is finished, maintaining the reaction temperature at 200 ℃ and the reaction pressure at 2.5MPa for continuous reaction for 2 hours;
(5) After the completion of the reaction, the crude terephthalic acid-containing mixture was filtered and washed with 80 ℃ acetic acid and 80 ℃ distilled water in this order, with the amounts of acetic acid and distilled water being 500g. Measuring the content of aldehyde intermediates by adopting high performance liquid chromatography after drying;
The content of p-carboxybenzaldehyde was found to be 165ppm by analytical calculation. For ease of illustration and comparison, catalyst compositions, reaction conditions, and analytical results are listed in the table.
[ Example 6 ]
The example uses paraxylene as a raw material:
(1) Mixing 2.12g Co(OAc)2·4H2O、6.26g Mn(OAc)2·4H2O、11.48g HBr（48wt%H2O）、21.2g NH4(OAc)2、21.2g 1- ethyl-3-methylimidazole acetate and 3816g of acetic acid, and adding into a 5L titanium reaction kettle;
(2) Firstly, exhausting air in the reaction kettle by using argon, then pressurizing to 1.5MPa, and regulating a back pressure valve behind a condensing pipe to keep the pressure in the reaction kettle stable;
(3) Stirring and heating, when the temperature reaches 200 ℃, introducing high-purity air at a rate of 20L/min until the pressure reaches 2.5MPa, and then adding 424g of paraxylene into a reaction kettle at a rate of 4.89g/min for reaction;
(4) After the paraxylene feeding is finished, maintaining the reaction temperature at 200 ℃ and the reaction pressure at 2.5MPa for continuous reaction for 2 hours;
(5) After the completion of the reaction, the crude terephthalic acid-containing mixture was filtered and washed with 80 ℃ acetic acid and 80 ℃ distilled water in this order, with the amounts of acetic acid and distilled water being 500g. Measuring the content of aldehyde intermediates by adopting high performance liquid chromatography after drying;
The content of p-carboxybenzaldehyde was found to be 165ppm by analytical calculation. For ease of illustration and comparison, catalyst compositions, reaction conditions, and analytical results are listed in the table.
[ Example 7 ]
The example uses meta-xylene as a raw material:
(1) 2.12g Co(OAc)2·4H2O、6.26g Mn(OAc)2·4H2O、11.48g HBr（48wt%H2O）、21.2g NH4(OAc)2、21.2g 1- butyl-3-methylimidazole bromide and 3816g acetic acid are mixed and added into a 5L titanium reaction kettle;
(2) Firstly, exhausting air in the reaction kettle by using argon, then pressurizing to 1.5MPa, and regulating a back pressure valve behind a condensing pipe to keep the pressure in the reaction kettle stable;
(3) Stirring and heating, when the temperature reaches 200 ℃, introducing high-purity air at a rate of 20L/min until the pressure reaches 2.5MPa, and then adding 424g of m-xylene into a reaction kettle at a rate of 4.88g/min for reaction;
(4) After the feeding of the m-xylene is finished, maintaining the reaction temperature at 200 ℃ and the reaction pressure at 2.5MPa for continuous reaction for 2 hours;
(5) After the reaction was completed, the mixture containing crude isophthalic acid was filtered and washed with 80 ℃ acetic acid and 80 ℃ distilled water in this order, the amounts of acetic acid and distilled water being 500g. Measuring the content of aldehyde intermediates by adopting high performance liquid chromatography after drying;
the content of m-carboxybenzaldehyde was calculated by analysis to be 108ppm. For ease of illustration and comparison, catalyst compositions, reaction conditions, and analytical results are listed in the table.
[ Example 8 ]
The example uses 2, 6-dimethylnaphthalene as raw material:
(1) 3.68g Co(OAc)2·4H2O、10.86g Mn(OAc)2·4H2O、19.93g HBr（48wt%H2O）、31.25g NH4(OAc)2、31.25g 1- ethyl-3-methylimidazole acetate and 5623.92g acetic acid are mixed and added into a 5L titanium reaction kettle;
(2) Firstly, exhausting air in the reaction kettle by using argon, then pressurizing to 1.5MPa, and regulating a back pressure valve behind a condensing pipe to keep the pressure in the reaction kettle stable;
(3) Stirring and heating, when the temperature reaches 200 ℃, introducing high-purity air at a rate of 20L/min until the pressure reaches 2.5MPa, and then adding 625g of 2, 6-dimethylnaphthalene into a reaction kettle at a rate of 6.19g/min for reaction;
(4) After the 2, 6-dimethylnaphthalene feeding is finished, maintaining the reaction temperature at 200 ℃ and the reaction pressure at 2.5MPa for continuous reaction for 2 hours;
(5) After the completion of the reaction, the mixture containing crude 2, 6-naphthalenedicarboxylic acid was filtered and washed successively with 80℃acetic acid and 80℃distilled water, both in an amount of 500g. Measuring the content of aldehyde intermediates by adopting high performance liquid chromatography after drying;
The content of 6-formyl-2-naphthoic acid was calculated by analysis to be 112ppm. For ease of illustration and comparison, catalyst compositions, reaction conditions, and analytical results are listed in the table.
[ Example 9]
The example uses 2, 6-diisopropyl naphthalene as raw material:
(1) 4.25g Co(OAc)2·4H2O、12.54g Mn(OAc)2·4H2O、22.99g HBr（48wt%H2O）、42.47g NH4(OAc)2、42.47g 1- ethyl-3-methylimidazole acetate and 7643.88g acetic acid are mixed and added into a 5L titanium reaction kettle;
(2) Firstly, exhausting air in the reaction kettle by using argon, then pressurizing to 1.5MPa, and regulating a back pressure valve behind a condensing pipe to keep the pressure in the reaction kettle stable;
(3) Stirring and heating, when the temperature reaches 200 ℃, introducing high-purity air at a rate of 20L/min until the pressure reaches 2.5MPa, and then adding 849.32g of 2, 6-diisopropylnaphthalene into a reaction kettle at a rate of 8.95g/min for reaction;
(4) After the 2, 6-diisopropylnaphthalene is fed, maintaining the reaction temperature at 200 ℃ and the reaction pressure at 2.5MPa for continuous reaction for 2 hours;
(5) After the completion of the reaction, the mixture containing crude 2, 6-naphthalenedicarboxylic acid was filtered and washed successively with 80℃acetic acid and 80℃distilled water, both in an amount of 500g. Measuring the content of aldehyde intermediates by adopting high performance liquid chromatography after drying;
the content of 6-formyl-2-naphthoic acid was 105ppm and the content of 6-acetyl-2-naphthoic acid was 89ppm as calculated by analysis. For ease of illustration and comparison, catalyst compositions, reaction conditions, and analytical results are listed in the table.
[ Example 10 ]
The example uses 2-methyl-6-acetyl naphthalene as raw material:
(1) Mixing 3.68g Co(OAc)2·4H2O、10.86g Mn(OAc)2·4H2O、19.93g HBr（48wt%H2O）、36.8g NH4(OAc)2、36.8g 1- ethyl-3-methylimidazole acetate and 6624g acetic acid, and adding into a 5L titanium reaction kettle;
(2) Firstly, exhausting air in the reaction kettle by using argon, then pressurizing to 1.5MPa, and regulating a back pressure valve behind a condensing pipe to keep the pressure in the reaction kettle stable;
(3) Stirring and heating, when the temperature reaches 200 ℃, introducing high-purity air at a rate of 20L/min until the pressure reaches 2.5MPa, and then adding 736g of 2-methyl-6-acetylnaphthalene into a reaction kettle at a rate of 8.50g/min for reaction;
(4) After the 2-methyl-6-acetylnaphthalene is fed, maintaining the reaction temperature at 200 ℃ and the reaction pressure at 2.5MPa for continuous reaction for 2 hours;
(5) After the completion of the reaction, the mixture containing crude 2, 6-naphthalenedicarboxylic acid was filtered and washed successively with 80℃acetic acid and 80℃distilled water, both in an amount of 500g. Measuring the content of aldehyde intermediates by adopting high performance liquid chromatography after drying;
the content of 6-formyl-2-naphthoic acid was found to be 98ppm and the content of 6-acetyl-2-naphthoic acid was found to be 101ppm by analytical calculation. For ease of illustration and comparison, catalyst compositions, reaction conditions, and analytical results are listed in the table.
[ Comparative example 1]
The comparative example uses paraxylene as a raw material:
(1) 2.12g Co(OAc)2·4H2O、6.26g Mn(OAc)2·4H2O、11.48g HBr（48wt%H2O） g and 3816g of acetic acid are mixed and added into a 5L titanium reaction kettle;
(2) Firstly, exhausting air in the reaction kettle by using argon, then pressurizing to 1.5MPa, and regulating a back pressure valve behind a condensing pipe to keep the pressure in the reaction kettle stable;
(3) Stirring and heating, when the temperature reaches 200 ℃, introducing high-purity air at a rate of 20L/min until the pressure reaches 2.5MPa, and then adding 424g of paraxylene into a reaction kettle at a rate of 4.89g/min for reaction;
(4) After the paraxylene feeding is finished, maintaining the reaction temperature at 200 ℃ and the reaction pressure at 2.5MPa for continuous reaction for 2 hours;
(5) After the completion of the reaction, the crude terephthalic acid-containing mixture was filtered and washed with 80 ℃ acetic acid and 80 ℃ distilled water in this order, with the amounts of acetic acid and distilled water being 500g. Measuring the content of aldehyde intermediates by adopting high performance liquid chromatography after drying;
the content of p-carboxybenzaldehyde was 4385ppm by analytical calculation. For ease of illustration and comparison, catalyst compositions, reaction conditions, and analytical results are listed in the table.
[ Comparative example 2]
The comparative example uses meta-xylene as the raw material:
(1) 2.12g Co(OAc)2·4H2O、6.26g Mn(OAc)2·4H2O、11.48g HBr（48wt%H2O） g and 3816g of acetic acid are mixed and added into a 5L titanium reaction kettle;
(2) Firstly, exhausting air in the reaction kettle by using argon, then pressurizing to 1.5MPa, and regulating a back pressure valve behind a condensing pipe to keep the pressure in the reaction kettle stable;
(3) Stirring and heating, when the temperature reaches 200 ℃, introducing high-purity air at a rate of 20L/min until the pressure reaches 2.5MPa, and then adding 424g of m-xylene into a reaction kettle at a rate of 4.88g/min for reaction;
(4) After the feeding of the m-xylene is finished, maintaining the reaction temperature at 200 ℃ and the reaction pressure at 2.5MPa for continuous reaction for 2 hours;
(5) After the reaction was completed, the mixture containing crude isophthalic acid was filtered and washed with 80 ℃ acetic acid and 80 ℃ distilled water in this order, the amounts of acetic acid and distilled water being 500g. Measuring the content of aldehyde intermediates by adopting high performance liquid chromatography after drying;
The content of m-carboxybenzaldehyde was found to be 4077ppm by analytical calculation. For ease of illustration and comparison, catalyst compositions, reaction conditions, and analytical results are listed in the table.
[ Comparative example 3]
In the comparative example, 2, 6-dimethylnaphthalene is used as a raw material:
(1) 3.68g Co(OAc)2·4H2O、10.86g Mn(OAc)2·4H2O、19.93g HBr（48wt%H2O g and 5623.92g of acetic acid are mixed and added into a 5L titanium reaction kettle;
(2) Firstly, exhausting air in the reaction kettle by using argon, then pressurizing to 1.5MPa, and regulating a back pressure valve behind a condensing pipe to keep the pressure in the reaction kettle stable;
(3) Stirring and heating, when the temperature reaches 200 ℃, introducing high-purity air at a rate of 20L/min until the pressure reaches 2.5MPa, and then adding 625g of 2, 6-dimethylnaphthalene into a reaction kettle at a rate of 6.19g/min for reaction;
(4) After the 2, 6-dimethylnaphthalene feeding is finished, maintaining the reaction temperature at 200 ℃ and the reaction pressure at 2.5MPa for continuous reaction for 2 hours;
(5) After the completion of the reaction, the mixture containing crude 2, 6-naphthalenedicarboxylic acid was filtered and washed successively with 80℃acetic acid and 80℃distilled water, both in an amount of 500g. Measuring the content of aldehyde intermediates by adopting high performance liquid chromatography after drying;
The content of 6-formyl-2-naphthoic acid was calculated by analysis to be 8568ppm. For ease of illustration and comparison, catalyst compositions, reaction conditions, and analytical results are listed in the table.
[ Comparative example 4]
In the comparative example, 2, 6-diisopropylnaphthalene is used as a raw material:
(1) 4.25g Co(OAc)2·4H2O、12.54g Mn(OAc)2·4H2O、22.99g HBr（48wt%H2O） g and 7643.88g of acetic acid are mixed and added into a 5L titanium reaction kettle;
(2) Firstly, exhausting air in the reaction kettle by using argon, then pressurizing to 1.5MPa, and regulating a back pressure valve behind a condensing pipe to keep the pressure in the reaction kettle stable;
(3) Stirring and heating, when the temperature reaches 200 ℃, introducing high-purity air at a rate of 20L/min until the pressure reaches 2.5MPa, and then adding 849.32g of 2, 6-diisopropylnaphthalene into a reaction kettle at a rate of 8.95g/min for reaction;
(4) After the 2, 6-diisopropylnaphthalene is fed, maintaining the reaction temperature at 200 ℃ and the reaction pressure at 2.5MPa for continuous reaction for 2 hours;
(5) After the completion of the reaction, the mixture containing crude 2, 6-naphthalenedicarboxylic acid was filtered and washed successively with 80℃acetic acid and 80℃distilled water, both in an amount of 500g. Measuring the content of aldehyde intermediates by adopting high performance liquid chromatography after drying;
The content of 6-formyl-2-naphthoic acid was 4089ppm and the content of 6-acetyl-2-naphthoic acid was 2880ppm as calculated by analysis. For ease of illustration and comparison, catalyst compositions, reaction conditions, and analytical results are listed in the table.
[ Comparative example 5]
In the comparative example, 2-methyl-6-acetylnaphthalene is used as a raw material:
(1) Mixing 3.68g Co(OAc)2·4H2O、10.86g Mn(OAc)2·4H2O、19.93g HBr（48wt%H2O g and 6624g of acetic acid and adding into a 5L titanium reaction kettle;
(2) Firstly, exhausting air in the reaction kettle by using argon, then pressurizing to 1.5MPa, and regulating a back pressure valve behind a condensing pipe to keep the pressure in the reaction kettle stable;
(3) Stirring and heating, when the temperature reaches 200 ℃, introducing high-purity air at a rate of 20L/min until the pressure reaches 2.5MPa, and then adding 736g of 2-methyl-6-acetylnaphthalene into a reaction kettle at a rate of 8.50g/min for reaction;
(4) After the 2-methyl-6-acetylnaphthalene is fed, maintaining the reaction temperature at 200 ℃ and the reaction pressure at 2.5MPa for continuous reaction for 2 hours;
(5) After the completion of the reaction, the mixture containing crude 2, 6-naphthalenedicarboxylic acid was filtered and washed successively with 80℃acetic acid and 80℃distilled water, both in an amount of 500g. Measuring the content of aldehyde intermediates by adopting high performance liquid chromatography after drying;
The content of 6-formyl-2-naphthoic acid was calculated by analysis to be 3865ppm, and the content of 6-acetyl-2-naphthoic acid was calculated to be 101ppm. For ease of illustration and comparison, catalyst compositions, reaction conditions, and analytical results are listed in the table.
In the table, the aldehyde intermediate of 2-methyl-6-acetylnaphthalene as raw material and the front and back represent the contents of 2-formyl-6-naphthoic acid and 2-acetyl-6-naphthoic acid respectively.