CN113185417B - Red base B separation process - Google Patents
Red base B separation process Download PDFInfo
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- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C213/00—Preparation of compounds containing amino and hydroxy, amino and etherified hydroxy or amino and esterified hydroxy groups bound to the same carbon skeleton
- C07C213/02—Preparation of compounds containing amino and hydroxy, amino and etherified hydroxy or amino and esterified hydroxy groups bound to the same carbon skeleton by reactions involving the formation of amino groups from compounds containing hydroxy groups or etherified or esterified hydroxy groups
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- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C213/00—Preparation of compounds containing amino and hydroxy, amino and etherified hydroxy or amino and esterified hydroxy groups bound to the same carbon skeleton
- C07C213/10—Separation; Purification; Stabilisation; Use of additives
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- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C231/00—Preparation of carboxylic acid amides
- C07C231/12—Preparation of carboxylic acid amides by reactions not involving the formation of carboxamide groups
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- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C231/00—Preparation of carboxylic acid amides
- C07C231/22—Separation; Purification; Stabilisation; Use of additives
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Abstract
The invention mainly relates to the field of organic synthesis, and discloses a high-efficiency separation process in the production process of haematochrome B (2-methoxyl-4-nitro-aniline). Aiming at nitration reaction liquid carried out by a microchannel reactor, the process adopts the salting-out effect in an acetic acid system and the difference of hydrolysis conditions of two main nitration products, and sets a series of operation methods for improving the separation efficiency of 2-methoxy-4-nitro-acetanilide and 2-methoxy-5-nitro-acetanilide. The invention fills the blank of the high-efficiency separation technology of the existing production process of the haematochrome B, improves the separation efficiency, shortens the production period and reduces the overall production cost.
Description
Technical Field
The invention belongs to the field of organic chemical industry, and particularly relates to a red base B separation process.
Technical Field
The red base B (2-methoxyl-4-nitro-aniline) is an important organic dye, is mainly used for dyeing and printing color development of cotton fiber fabrics, is also used for manufacturing organic pigments such as fast pigments, purplish red, golden yellow, black and the like, is widely applied to the printing and dyeing industry, and has large market demand. The production preparation is obtained by nitration and hydrolysis processes of o-methoxyacetanilide, but due to the nitration selectivity problem of the prior art, the nitration product contains two substances, namely 2-methoxy-4-nitro-acetanilide (about 85 percent) and 2-methoxy-5-nitro-acetanilide (about 15 percent), and the two substances can respectively obtain two products, namely a haematochrome B (2-methoxy-4-nitro-aniline) and a macrohaematochrome RC (2-methoxy-5-nitro-aniline), by hydrolyzing acetyl groups (as shown below). The scarlet base RC is still an important textile fiber dye and organic dye although the market demand of the scarlet base RC is not as great as that of the scarlet base B. Therefore, how to obtain two high-purity products through an efficient separation process is an important measure for improving the competitiveness of the process level.
Disclosure of Invention
Aiming at the problems that a main nitration product and a byproduct are difficult to separate in the continuous flow production process of the haematochrome B, the traditional separation method has high resource consumption, long separation period and the like, the invention provides a novel high-efficiency separation method for nitration products and hydrolysis reaction based on a production method for carrying out nitration reaction in an acetic acid system by adopting a micro-channel continuous flow reactor.
The purpose of the invention is realized by the following technical scheme:
a red base B separation process comprises the following specific steps:
(1) Preparing acetic acid mixed solution containing 30 mass percent of o-methoxyacetanilide; mixing the acetic acid mixed solution and concentrated nitric acid according to the molar ratio of the concentrated nitric acid to the o-methoxyacetanilide of 1.3:1, simultaneously pumping into a microchannel reactor; the total flow rate is 60 g/min-150 g/min, the temperature is 80 ℃, the retention time is 60s, and the pressure is 5.5bar; obtaining nitration reaction liquid;
(2) Adding sodium salt into the nitration reaction liquid in the step (1) to ensure that the mass ratio of the sodium salt to the nitration reaction liquid is 0.02 to 0.1:1, stirring, cooling the reaction liquid to 5-30 ℃, carrying out heat preservation crystallization for 30-90min to obtain a solid-liquid mixture, and filtering the solid-liquid mixture to obtain a nitration product 2-methoxy-4-nitro-acetanilide filter cake and a filtrate of the nitration mixed product;
(3) Adding the filter cake obtained in the step (2) into 15% of liquid caustic soda, and heating to 90 ℃ for reacting for 2 hours; cooling to 30 deg.C, precipitating crystal, and filtering to obtain haematochrome B, i.e. 2-methoxy-4-nitro-aniline;
(4) Carrying out reduced pressure concentration on the nitration mixed product filtrate in the step (2), and removing acetic acid to obtain a concentrated solution; cooling the concentrated solution to 5-30 ℃, carrying out heat preservation and crystallization for 30-90min, and stirring to obtain slurry; filtering to obtain a filter cake containing 2-methoxy-4-nitro-acetanilide and 2-methoxy-5-nitro-acetanilide;
(5) Adding the filter cake obtained in the step (4) into a reaction kettle, adding water to prepare slurry with the solid content of 33%, stirring, heating to 60-100 ℃, detecting the pH value in the slurry in real time by using an online pH meter, slowly adding liquid alkali dropwise until the pH value is 11.0, continuously reducing the pH value in the reaction process, supplementing the liquid alkali at any time, keeping the pH value range within 11.0 +/-0.5 until the reduction range of the pH value is less than 0.2 within 10min, and stopping the reaction to obtain hydrolysis reaction liquid;
(6) Dropwise adding inorganic strong acid into the hydrolysis reaction liquid in the step (5), adjusting the pH value to 2-4, adding soluble sodium salt to enable the content of the sodium salt in the reaction liquid to be 2-10%, cooling to 5-30 ℃, carrying out heat preservation crystallization for 30-90min, filtering to obtain high-purity 2-methoxy-5-nitro-acetanilide solid, continuously dropwise adding liquid alkali into the filtrate, adjusting the pH value to 7.0-8.0, and filtering to obtain the high-purity haematochrome B solid.
Further, in the step (2) or the step (6), the sodium salt is one or more of sodium sulfate, sodium chloride, sodium acetate or sodium nitrate.
Further, in the step (2), the sodium salt is sodium acetate.
Further, the sodium salt content in the step (2) is 6%.
Further, in the step (6), the sodium salt is sodium chloride.
Further, cooling the reaction solution in the step (2) to 10 ℃, and carrying out heat preservation and crystallization for 60min.
Further, the inorganic strong acid in the step (6) is one or more of sulfuric acid, hydrochloric acid and nitric acid.
Further, cooling the concentrated solution in the step (4) to 10 ℃, and carrying out heat preservation and crystallization for 60min.
Further, the temperature of the slurry in the step (5) is increased to 90 DEG o C。
Further, in the step (6), the pH value is 3, the content of sodium salt in the reaction liquid is 9.3 percent, the temperature is reduced to 10 ℃, and the temperature is kept for crystallization for 60min.
The invention has the advantages of
The invention makes creative optimization and improvement aiming at the separation of the product and the byproduct in the o-methoxyacetanilide nitration process which takes acetic acid as a solvent and nitric acid as a nitration reagent and the separation of the product and the byproduct in the nitration product hydrolysis process, and can obviously improve the production efficiency of the haematochrome B continuous flow production process and reduce the production cost.
(1) The poor solvent effect and salting-out effect are utilized to change the solubility of the main product and the by-product in the nitration reaction liquid, and the difference of the solubility along with the temperature change is further utilized to realize the high-efficiency separation of the products.
(2) The hydrolysis process is optimized by utilizing the difference of the hydrolysis conditions of the main product and the by-product, the interlocking control of constant pH value range, constant temperature and constant pressure of the hydrolysis reactor is completed by adopting an automatic control system, and the 2-methoxy-4-nitro-acetanilide is ensured to be completely hydrolyzed, while the 2-methoxy-5-nitro-acetanilide is not hydrolyzed basically.
(3) Hydrochloric acid/sulfuric acid is adopted to adjust the pH value of the hydrolysate, so that the main hydrolysis product 2-methoxy-4-nitro-aniline can be generated into hydrochloride or sulfate with higher solubility, and the hydrochloride or sulfate can be completely dissolved in water. Further utilizes salting-out effect to reduce the solubility of the 2-methoxy-5-nitro-acetanilide, and realizes the high-efficiency separation of the main hydrolysis product and the non-hydrolyzed by-product.
Detailed Description
Example 1
(1) Adding 10mol of o-methoxyacetanilide into 3850g of acetic acid solution to prepare acetic acid mixed solution with the mass fraction of 30% of o-methoxyacetanilide, 1204g of concentrated nitric acid with the mass fraction of 68%, wherein the molar ratio of the concentrated nitric acid to the o-methoxyacetanilide is 1.3: simultaneously pumping two materials into a microchannel reactor, wherein the total flow rate is 150g/min, the reaction temperature is 80 ℃, the retention time is 60s, and the pressure is 5.5bar, and completing nitration reaction to obtain nitration reaction liquid containing 2-methoxy-4-nitro-acetanilide and 2-methoxy-5-nitro-acetanilide; performing liquid chromatograph detection analysis on the nitration reaction liquid, wherein the reaction conversion rate is 99.5 percent, namely 85 percent of 2-methoxy-4-nitro-acetanilide and 15 percent of 2-methoxy-5-nitro-acetanilide;
(2) Adding 402g of sodium acetate into the nitration reaction liquid in the step (1), wherein the mass ratio of the sodium salt to the nitration reaction liquid is 0.06:1, stirring, cooling to 10 ℃, keeping the temperature for crystallization for 60min, and filtering to obtain a high-purity nitration product 2-methoxy-4-nitro-acetanilide filter cake (with the liquid chromatography purity of 99.2%, dry weight of 1688.7g and cooling crystallization yield of 95%) and a nitration mixed product filtrate;
(3) Adding 2785g of 15% liquid caustic soda into the filter cake obtained in the step (2), heating to 90 ℃ for reaction for 2 hours, cooling to 30 ℃, and filtering to obtain 1344g of a high-purity haematochrome B (2-methoxy-4-nitro-aniline) product with the purity of 99.3%;
(4) Carrying out reduced pressure concentration on the nitrified mixture filtrate obtained in the step (2), and removing 3850g of acetic acid to obtain a concentrated solution; cooling the concentrated solution to 10 ℃, keeping the temperature for crystallization for 60min, and stirring to obtain slurry; filtration gave a cake of mixture (400.8 g dry weight, containing 87.4g of 2-methoxy-4-nitro-acetanilide and 313.4g of 2-methoxy-5-nitro-acetanilide);
(5) Adding the mixture filter cake obtained in the step (4) into a reaction kettle, adding 800g of water to prepare slurry with the solid content of 33%, stirring, heating to 90 ℃, detecting the pH value in the slurry in real time by using an online pH meter, slowly adding sodium hydroxide to the pH value of 11.0, continuously reducing the pH value in the reaction process, supplementing the sodium hydroxide at any time to maintain the pH value range of 11.0 +/-0.5 until the reduction range of the pH value is less than 0.2 within 10min, stopping the reaction, and adding 20g of sodium hydroxide cumulatively to obtain hydrolysis reaction liquid;
(6) And (3) dropwise adding 64.9g of 31% concentrated hydrochloric acid into the hydrolysis reaction liquid in the step (5) until the pH value is =3.0, adding 112g of sodium chloride, wherein the content of sodium salt in the reaction liquid is 8.7%, cooling to 10 ℃, keeping the temperature, crystallizing for 60min, filtering to obtain a high-purity 2-methoxy-5-nitro-acetanilide filter cake (313 g of dry weight, 99.1% of liquid chromatography purity and 99% of yield), continuously dropwise adding liquid alkali into the filtrate to adjust the pH value to 7.0-8.0, and filtering to obtain a haematochrome B product (87g of dry weight, 2-methoxy-4-nitro-aniline, 99.0% of liquid chromatography purity and 99% of yield).
Example 2
(1) Adding 10mol of o-methoxyacetanilide into 3850g of acetic acid solution to prepare acetic acid mixed solution with the mass fraction of 30% of o-methoxyacetanilide, preparing 13mol of nitric acid into 1204g of concentrated nitric acid with the mass fraction of 68%, wherein the molar ratio of the concentrated nitric acid to the o-methoxyacetanilide is 1.3: simultaneously pumping two materials into a microchannel reactor, wherein the total flow rate is 60g/min, the reaction temperature is 80 ℃, the retention time is 60s, and the pressure is 5.5bar, and completing nitration reaction to obtain nitration reaction liquid containing 2-methoxy-4-nitro-acetanilide and 2-methoxy-5-nitro-acetanilide; performing liquid chromatograph detection analysis on the nitration reaction liquid, wherein the reaction conversion rate is 99.5 percent, wherein the 2-methoxy-4-nitro-acetanilide is 85 percent, and the 2-methoxy-5-nitro-acetanilide is 15 percent;
(2) Adding 670.4g of sodium acetate into the nitration reaction liquid in the step (1), wherein the mass ratio of the sodium salt to the nitration reaction liquid is 0.1:1, stirring, cooling to 15 ℃, keeping the temperature for crystallization for 90min, and filtering to obtain a high-purity nitration product 2-methoxy-4-nitro-acetanilide filter cake (with the liquid chromatography purity of 99.0%, dry weight of 1634g, and cooling crystallization yield of 92%) and a nitration mixed product filtrate;
(3) 2694g of 15% caustic soda liquid is added into the filter cake obtained in the step (2), the temperature is raised to 90 ℃ for reaction for 2 hours, the temperature is lowered to 30 ℃, and the high-purity haematochrome B (2-methoxy-4-nitro-aniline) product 1305g with the purity of 99.1% is obtained through filtration;
(4) Carrying out reduced pressure concentration on the nitrified mixture filtrate obtained in the step (2), and removing 3850g of acetic acid to obtain a concentrated solution; cooling the concentrated solution to 10 ℃, keeping the temperature for crystallization for 60min, and stirring to obtain slurry; filtration gave a cake of mixture (466 g dry weight, containing 152.6g of 2-methoxy-4-nitro-acetanilide and 313.4g of 2-methoxy-5-nitro-acetanilide);
(5) Adding the mixture filter cake obtained in the step (4) into a reaction kettle, adding 932g of water to prepare slurry with the solid content of 33%, stirring, heating to 90 ℃, detecting the pH value in the slurry in real time by using an online pH meter, slowly adding sodium hydroxide to the pH value of 11.0, continuously reducing the pH value in the reaction process, supplementing sodium hydroxide at any time to maintain the pH value range of 11.0 +/-0.5 until the pH value is reduced to be less than 0.2 within 10min, stopping the reaction, and adding 34.9g of sodium hydroxide cumulatively to obtain hydrolysis reaction liquid;
(6) And (3) dropwise adding 113g of 31% concentrated hydrochloric acid into the hydrolysis reaction solution obtained in the step (5) until the pH value is =4.0, adding 150g of sodium chloride, wherein the content of sodium salt in the reaction solution is 10%, cooling to 10 ℃, keeping the temperature, crystallizing for 60min, filtering to obtain a high-purity 2-methoxy-5-nitro-acetanilide filter cake (319.4 g of dry weight, 99.0% of liquid chromatogram purity and 99% of yield), continuously dropwise adding liquid alkali into the filtrate to adjust the pH value to 7.0-8.0, and filtering to obtain a haematochrome B product (146.2g of dry weight, 2-methoxy-4-nitro-aniline, 99.0% of liquid chromatogram purity and 99% of yield).
Example 3
(1) Adding 10mol of o-methoxyacetanilide into 3850g of acetic acid solution to prepare acetic acid mixed solution with the mass fraction of 30% of o-methoxyacetanilide, preparing 13mol of nitric acid into 1204g of concentrated nitric acid with the mass fraction of 68%, wherein the molar ratio of the concentrated nitric acid to the o-methoxyacetanilide is 1.3: simultaneously pumping two materials into a microchannel reactor, wherein the total flow rate is 60g/min, the reaction temperature is 80 ℃, the retention time is 60s, and the pressure is 5.5bar, and completing nitration reaction to obtain nitration reaction liquid containing 2-methoxy-4-nitro-acetanilide and 2-methoxy-5-nitro-acetanilide; performing liquid chromatograph detection analysis on the nitration reaction liquid, wherein the reaction conversion rate is 99.5 percent, wherein the 2-methoxy-4-nitro-acetanilide is 85 percent, and the 2-methoxy-5-nitro-acetanilide is 15 percent;
(2) Adding 134g of sodium acetate into the nitration reaction liquid in the step (1), wherein the mass ratio of sodium salt to nitration reaction liquid is 0.02:1, stirring, cooling to 15 ℃, carrying out heat preservation and crystallization for 90min, and filtering to obtain a high-purity nitration product 2-methoxy-4-nitro-acetanilide filter cake (with the liquid chromatography purity of 99.5%, the dry weight of 1606.5g, and the cooling crystallization yield of 90%) and nitration mixed product filtrate;
(3) 2649g of 15% liquid caustic soda is added into the filter cake obtained in the step (2), the temperature is raised to 90 ℃ for reaction for 2 hours, the temperature is reduced to 30 ℃, and the filtration is carried out to obtain 1283g of high-purity haematochrome B (2-methoxy-4-nitro-aniline) product with the purity of 99.6%;
(4) Carrying out reduced pressure concentration on the nitrified mixture filtrate obtained in the step (2), and removing 3850g of acetic acid to obtain a concentrated solution; cooling the concentrated solution to 10 ℃, carrying out heat preservation and crystallization for 60min, and stirring to obtain slurry; filtration gave a cake of mixture (493.5 g dry weight, containing 180.1g of 2-methoxy-4-nitro-acetanilide and 313.4g of 2-methoxy-5-nitro-acetanilide);
(5) Adding the mixture filter cake obtained in the step (4) into a reaction kettle, adding 987g of water to prepare slurry with the solid content of 33%, stirring, heating to 60 ℃, detecting the pH value in the slurry in real time by using an online pH meter, slowly adding sodium hydroxide to the pH value of 11.0, continuously reducing the pH value in the reaction process, supplementing sodium hydroxide at any time to maintain the pH value range of 11.0 +/-0.5 until the pH value is reduced to be less than 0.2 within 10min, stopping the reaction, and adding 41.2g of sodium hydroxide in an accumulated manner to obtain hydrolysis reaction liquid;
(6) And (3) dropwise adding 133.7g of 31% concentrated hydrochloric acid into the hydrolysis reaction liquid in the step (5) until the pH value is =2.0, adding 35g of sodium chloride, wherein the content of sodium salt in the reaction liquid is 2.2%, cooling to 10 ℃, preserving heat, crystallizing for 60min, filtering to obtain a high-purity 2-methoxy-5-nitro-acetanilide filter cake (301 g of dry weight, 99.0% of liquid chromatogram purity and 96.0% of yield), continuously dropwise adding liquid alkali into the filtrate to adjust the pH value to 7.5 +/-0.5, and filtering to obtain a haematochrome B product (183.7 g of dry weight, 2-methoxy-4-nitro-aniline, 98.0% of liquid chromatogram purity and 99% of yield).
Example 4
(1) Adding 10mol of o-methoxyacetanilide into 3850g of acetic acid solution to prepare acetic acid mixed solution with the mass fraction of 30% of o-methoxyacetanilide, preparing 13mol of nitric acid into 1204g of concentrated nitric acid with the mass fraction of 68%, wherein the molar ratio of the concentrated nitric acid to the o-methoxyacetanilide is 1.3: simultaneously pumping two materials into a microchannel reactor, wherein the total flow rate is 60g/min, the reaction temperature is 80 ℃, the retention time is 60s, and the pressure is 5.5bar, and completing nitration reaction to obtain nitration reaction liquid containing 2-methoxy-4-nitro-acetanilide and 2-methoxy-5-nitro-acetanilide; performing liquid chromatograph detection analysis on the nitration reaction liquid, wherein the reaction conversion rate is 99.5 percent, wherein the 2-methoxy-4-nitro-acetanilide is 85 percent, and the 2-methoxy-5-nitro-acetanilide is 15 percent;
(2) Adding 268g of sodium acetate into the nitration reaction liquid in the step (1), wherein the mass ratio of the sodium salt to the nitration reaction liquid is 0.04:1, stirring, cooling to 5 ℃, carrying out heat preservation and crystallization for 90min, and filtering to obtain a high-purity nitration product 2-methoxy-4-nitro-acetanilide filter cake (with the liquid chromatography purity being 99.5%, the dry weight being 1634g, and the cooling crystallization yield being 92%) and nitration mixed product filtrate;
(3) 2695g of 15% liquid caustic soda is added into the filter cake obtained in the step (2), the temperature is raised to 90 ℃ for reaction for 2h, the temperature is lowered to 30 ℃, and the high-purity haematochrome B (2-methoxy-4-nitro-aniline) product 1306g is obtained through filtration, and the product purity is 99.7%;
(4) Carrying out reduced pressure concentration on the nitration mixture filtrate in the step (2), and removing 3850g of acetic acid to obtain a concentrated solution; cooling the concentrated solution to 10 ℃, carrying out heat preservation and crystallization for 60min, and stirring to obtain slurry; filtration to give a cake of the mixture (466 g dry weight containing 152.6g of 2-methoxy-4-nitro-acetanilide and 313.4g of 2-methoxy-5-nitro-acetanilide);
(5) Adding the mixture filter cake obtained in the step (4) into a reaction kettle, adding 987g of water to prepare slurry with the solid content of 33%, stirring, heating to 90 ℃, detecting the pH value in the slurry in real time by using an online pH meter, slowly adding sodium hydroxide to the pH value of 11.0, continuously reducing the pH value in the reaction process, supplementing the sodium hydroxide at any time to maintain the pH value range of 11.0 +/-0.5 until the reduction range of the pH value is less than 0.2 within 10min, stopping the reaction, and adding 34.9g of sodium hydroxide cumulatively to obtain hydrolysis reaction liquid;
(6) And (3) dropwise adding 113g of 31% concentrated hydrochloric acid into the hydrolysis reaction liquid in the step (5) until the pH value is =2.5, adding 80g of sodium chloride, wherein the content of sodium salt in the reaction liquid is 5.2%, cooling to 10 ℃, keeping the temperature, crystallizing for 60min, filtering to obtain a high-purity 2-methoxy-5-nitro-acetanilide filter cake (dry weight is 312g, liquid chromatography purity is 99.0%, and yield is 98.5%), continuously dropwise adding liquid alkali into the filtrate to adjust the pH value to 7.0-8.0, and filtering to obtain a haematochrome B product (dry weight is 154g, 2-methoxy-4-nitro-aniline, liquid chromatography purity is 98.7%, and yield is more than 99%).
Example 5
(1) Adding 10mol of o-methoxyacetanilide into 3850g of acetic acid solution to prepare acetic acid mixed solution with the mass fraction of 30% of o-methoxyacetanilide, preparing 13mol of nitric acid into 1204g of concentrated nitric acid with the mass fraction of 68%, wherein the molar ratio of the concentrated nitric acid to the o-methoxyacetanilide is 1.3:1, pumping two materials into a microchannel reactor at the same time, wherein the total flow rate is 60g/min, the reaction temperature is 80 ℃, the retention time is 60s, and the pressure is 5.5bar, completing nitration reaction, and obtaining nitration reaction liquid containing 2-methoxy-4-nitro-acetanilide and 2-methoxy-5-nitro-acetanilide; performing liquid chromatograph detection analysis on the nitration reaction liquid, wherein the reaction conversion rate is 99.5 percent, wherein the 2-methoxy-4-nitro-acetanilide is 85 percent, and the 2-methoxy-5-nitro-acetanilide is 15 percent;
(2) Adding 670g of sodium acetate into the nitration reaction liquid in the step (1), wherein the mass ratio of the sodium salt to the nitration reaction liquid is 0.1:1, stirring, cooling to 5 ℃, carrying out thermal insulation crystallization for 90min, and filtering to obtain a high-purity nitration product 2-methoxy-4-nitro-acetanilide filter cake (with the liquid chromatography purity of 99.1%, the dry weight of 1460g, and the cooling crystallization yield of 91%) and a nitration mixed product filtrate;
(3) 2695g of 15% liquid caustic soda is added into the filter cake obtained in the step (2), the temperature is raised to 90 ℃ for reaction for 2 hours, the temperature is reduced to 30 ℃, and the high-purity haematochrome B (2-methoxy-4-nitro-aniline) product 1245g with the purity of 99.2% is obtained by filtration;
(4) Carrying out reduced pressure concentration on the nitrified mixture filtrate obtained in the step (2), and removing 3850g of acetic acid to obtain a concentrated solution; cooling the concentrated solution to 5 ℃, keeping the temperature for crystallization for 90min, and stirring to obtain slurry; filtration gave a cake of the mixture (467 g dry weight, containing 150.6g of 2-methoxy-4-nitro-acetanilide and 315.4g of 2-methoxy-5-nitro-acetanilide);
(5) Adding the mixture filter cake obtained in the step (4) into a reaction kettle, adding 987g of water to prepare slurry with the solid content of 33%, wherein the sodium salt content in the reaction liquid is 2%, stirring, heating to 100 ℃, detecting the pH value in the slurry in real time by using an online pH meter, slowly adding sodium hydroxide to the pH value of 11.0, continuously decreasing the pH value in the reaction process, supplementing the sodium hydroxide at any time to maintain the pH value range of 11.0 +/-0.5 until the pH value decreases within 10min and is less than 0.2, stopping the reaction, and adding 34.4g of sodium hydroxide in an accumulated manner to obtain hydrolysis reaction liquid;
(6) And (3) dropwise adding 111.8g of 31% concentrated hydrochloric acid into the hydrolysis reaction liquid in the step (5) until the pH value is =4, adding 31g of sodium chloride, wherein the content of sodium salt in the reaction liquid is 2%, cooling to 30 ℃, carrying out heat preservation and crystallization for 30min, filtering to obtain a high-purity 2-methoxy-5-nitro-acetanilide filter cake (dry weight is 302g, liquid chromatography purity is 99.2%, yield is 98.0%), continuously dropwise adding liquid alkali into the filtrate to adjust the pH value to 7.0-8.0, and filtering to obtain a haematochrome B product (dry weight is 164g, 2-methoxy-4-nitro-aniline, liquid chromatography purity is 98.9%, and yield is more than 99%).
Example 6
(1) Adding 10mol of o-methoxyacetanilide into 3850g of acetic acid solution to prepare acetic acid mixed solution with the mass fraction of 30% of o-methoxyacetanilide, preparing 13mol of nitric acid into 1204g of concentrated nitric acid with the mass fraction of 68%, wherein the molar ratio of the concentrated nitric acid to the o-methoxyacetanilide is 1.3: simultaneously pumping two materials into a microchannel reactor, wherein the total flow rate is 60g/min, the reaction temperature is 80 ℃, the retention time is 60s, and the pressure is 5.5bar, and completing nitration reaction to obtain nitration reaction liquid containing 2-methoxy-4-nitro-acetanilide and 2-methoxy-5-nitro-acetanilide; performing liquid chromatograph detection analysis on the nitration reaction liquid, wherein the reaction conversion rate is 99.5 percent, wherein the 2-methoxy-4-nitro-acetanilide is 85 percent, and the 2-methoxy-5-nitro-acetanilide is 15 percent;
(2) Adding 670g of sodium sulfate into the nitration reaction liquid in the step (1), wherein the mass ratio of the sodium salt to the nitration reaction liquid is 0.1:1, stirring, cooling to 5 ℃, carrying out thermal insulation crystallization for 90min, and filtering to obtain a high-purity nitration product 2-methoxy-4-nitro-acetanilide filter cake (the liquid chromatography purity is 98.8%, the dry weight is 1223g, and the cooling crystallization yield is 89%) and a nitration mixed product filtrate;
(3) Adding 2018g of 15% liquid caustic soda into the filter cake obtained in the step (2), heating to 90 ℃, reacting for 2 hours, cooling to 30 ℃, and filtering to obtain 1201g of a high-purity haematochrome B (2-methoxy-4-nitro-aniline) product with the purity of 99.1%;
(4) Carrying out reduced pressure concentration on the nitrified mixture filtrate obtained in the step (2), and removing 3850g of acetic acid to obtain a concentrated solution; cooling the concentrated solution to 5 ℃, carrying out heat preservation and crystallization for 90min, and stirring to obtain slurry; filtering to obtain a mixture filter cake (451 g dry weight, 131g of 2-methoxy-4-nitro-acetanilide and 320g of 2-methoxy-5-nitro-acetanilide);
(5) Adding the mixture filter cake obtained in the step (4) into a reaction kettle, adding 916g of water to prepare slurry with the solid content of 33%, stirring, heating to 100 ℃, detecting the pH value in the slurry in real time by using an online pH meter, slowly adding sodium hydroxide to the pH value of 11.0, continuously reducing the pH value in the reaction process, supplementing sodium hydroxide at any time to maintain the pH value range of 11.0 +/-0.5 until the pH value is reduced within 10min to be less than 0.2, stopping the reaction, and adding 29.9g of sodium hydroxide cumulatively to obtain hydrolysis reaction liquid;
(6) And (3) dropwise adding 82.2g of 98% sulfuric acid into the hydrolysis reaction liquid in the step (5) until the pH value is =4, adding 30g of sodium sulfate, cooling to 30 ℃, carrying out thermal insulation crystallization for 30min, filtering to obtain a high-purity 2-methoxy-5-nitro-acetanilide filter cake (298 g of dry weight, 99% of liquid chromatography purity and 97.6% of yield), continuously dropwise adding liquid alkali into the filtrate to adjust the pH value to 7.0-8.0, and filtering to obtain a haematochrome B product (152g of dry weight, 2-methoxy-4-nitro-aniline, 98.0% of liquid chromatography purity and 99% of yield).
In order to better understand the technical solution of the present invention, the following further description of the novel method of the present invention is made with reference to specific examples, but it should not be understood that the scope of the subject matter of the present invention is limited to the following examples. All the technologies realized based on the above contents of the present invention belong to the scope of the present invention.
Claims (6)
1. A red base B separation process is characterized by comprising the following specific steps:
(1) Preparing acetic acid mixed liquor containing 30 mass percent of o-methoxyacetanilide; mixing the acetic acid mixed solution and concentrated nitric acid according to the molar ratio of the concentrated nitric acid to the o-methoxyacetanilide of 1.3:1, simultaneously pumping the mixture into a microchannel reactor; the total flow rate is 60 g/min-150 g/min, the temperature is 80 ℃, the retention time is 60s, and the pressure is 5.5bar; obtaining nitration reaction liquid;
(2) Adding sodium salt into the nitration reaction liquid in the step (1), wherein the mass ratio of the sodium salt to the nitration reaction liquid is 0.02 to 0.1:1, stirring, cooling the reaction liquid to 10 ℃, keeping the temperature, crystallizing for 60min to obtain a solid-liquid mixture, and filtering the solid-liquid mixture to obtain a nitration product 2-methoxy-4-nitro-acetanilide filter cake and a filtrate of the nitration mixed product;
(3) Adding the filter cake obtained in the step (2) into 15% of liquid caustic soda, and heating to 90 ℃ for reacting for 2 hours; cooling to 30 deg.C, precipitating crystal, and filtering to obtain haematochrome B, i.e. 2-methoxy-4-nitro-aniline;
(4) Carrying out reduced pressure concentration on the nitration mixed product filtrate in the step (2), and removing acetic acid to obtain a concentrated solution; cooling the concentrated solution to 10 ℃, carrying out heat preservation and crystallization for 60min, and stirring to obtain slurry; filtering to obtain a filter cake containing the 2-methoxy-4-nitro-acetanilide and the 2-methoxy-5-nitro-acetanilide;
(5) Adding the filter cake obtained in the step (4) into a reaction kettle, adding water to prepare slurry with the solid content of 33%, stirring, heating to 90 ℃, detecting the pH value in the slurry in real time by using an online pH meter, slowly dropwise adding liquid caustic soda to the pH value of 11.0, continuously reducing the pH value in the reaction process, supplementing the liquid caustic soda at any time to maintain the pH value range within 11.0 +/-0.5 until the pH value is reduced to be less than 0.2 within 10min, and stopping the reaction to obtain hydrolysis reaction liquid;
(6) Dropwise adding inorganic strong acid into the hydrolysis reaction liquid obtained in the step (5), adjusting the pH value to be 3, adding soluble sodium salt to enable the content of the sodium salt in the reaction liquid to be 9.3%, cooling to 10 ℃, keeping the temperature for crystallization for 60min, filtering to obtain high-purity 2-methoxy-5-nitro-acetanilide solid, continuously dropwise adding liquid caustic soda into the filtrate, adjusting the pH value to be 7.0 to 8.0, and filtering to obtain the high-purity haematochrome B solid.
2. The process for separating a red base B according to claim 1, wherein the sodium salt in step (2) or step (6) is one or more of sodium sulfate, sodium chloride, sodium acetate and sodium nitrate.
3. The process for separating a red pigment base B according to claim 2, wherein the sodium salt in step (2) is sodium acetate.
4. A process according to claim 2 or 3, wherein the sodium salt content in step (2) is 6%.
5. The process for separating a red base B according to claim 2, wherein the sodium salt in step (6) is sodium chloride.
6. The process for separating a red base B according to claim 1, wherein the strong inorganic acid in step (6) is one or more of sulfuric acid, hydrochloric acid and nitric acid.
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| JPH0784429B2 (en) * | 1986-11-20 | 1995-09-13 | 新日鐵化学株式会社 | Method for producing diaminobenzanilide derivative |
| DE4007535A1 (en) * | 1990-03-09 | 1991-09-12 | Hoechst Ag | WATER-INSOLUBLE AZO PAINTS, THEIR PRODUCTION AND USE |
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