阅读说明：本技术 一种碱性红中间体3-乙基氨基对甲基苯酚的生产工艺 (Production process of alkaline red intermediate 3-ethylaminop-methylphenol ) 是由 马学文 刘文平 葛德三 于 2020-11-20 设计创作，主要内容包括：本发明涉及一种碱性红中间体3-乙基氨基对甲基苯酚的生产工艺,具体包括如下步骤：步骤1、烷基化反应：邻甲苯胺与无水乙醇在催化剂磁性固体酸的作用下发生烷基化反应生成烷化物混合物,然后将所述烷化物混合物精馏制得N-乙基邻甲苯胺；所述烷基化反应的反应温度为60～120摄氏度；所述磁性固体酸的添加量为料液质量比4～6％；步骤2、磺化反应：N-乙基邻甲苯胺与发烟硫酸发生磺化反应生成3-乙基氨基对甲苯磺酸；步骤3、羟基化反应：3-乙基氨基对甲苯磺酸与氢氧化钾发生羟基化反应,生成3-乙基氨基对甲基苯酚钾盐；步骤4、酸析：3-乙基氨基对甲基苯酚钾盐与盐酸反应制得3-乙基氨基对甲基苯酚。本发明收率高、反应时间短。(The invention relates to a production process of alkaline red intermediate 3-ethylaminop-methylphenol, which specifically comprises the following steps: step 1, alkylation reaction: carrying out alkylation reaction on o-toluidine and absolute ethyl alcohol under the action of a catalyst magnetic solid acid to generate an alkylate mixture, and rectifying the alkylate mixture to obtain N-ethyl o-toluidine; the reaction temperature of the alkylation reaction is 60-120 ℃; the addition amount of the magnetic solid acid is 4-6% of the mass ratio of the feed liquid; step 2, sulfonation reaction: the N-ethyl o-toluidine and fuming sulfuric acid are subjected to sulfonation reaction to generate 3-ethylamino p-toluenesulfonic acid; step 3, hydroxylation reaction: hydroxylating 3-ethylaminopara-toluenesulfonic acid with potassium hydroxide to generate 3-ethylaminopara-methylphenol potassium salt; step 4, acid precipitation: 3-ethylaminop-methylphenol potassium salt reacts with hydrochloric acid to prepare 3-ethylaminop-methylphenol. The method has high yield and short reaction time.)

1. A production process of an alkaline red intermediate 3-ethylaminop-methylphenol is characterized by comprising the following steps:

step 1, alkylation reaction: carrying out alkylation reaction on o-toluidine and absolute ethyl alcohol under the action of a catalyst magnetic solid acid to generate an alkylate mixture, and then placing the alkylate mixture into a rectifying still for rectifying to obtain N-ethyl o-toluidine; the reaction temperature of the alkylation reaction is 60-120 ℃;

the addition amount of the magnetic solid acid is 3.0-5.5% of the mass ratio of the feed liquid;

step 2, sulfonation reaction: the N-ethyl o-toluidine and fuming sulfuric acid are subjected to sulfonation reaction to generate 3-ethylamino p-toluenesulfonic acid;

step 3, hydroxylation reaction: hydroxylating 3-ethylaminopara-toluenesulfonic acid with potassium hydroxide to generate 3-ethylaminopara-methylphenol potassium salt;

step 4, acid precipitation: 3-ethylaminop-methylphenol potassium salt reacts with hydrochloric acid to prepare 3-ethylaminop-methylphenol.

2. The process for producing basic red intermediate 3-ethylamino p-methylphenol according to claim 1,

step 1 the alkylation reaction comprises the following specific steps: adding o-toluidine and absolute ethyl alcohol into a pulping kettle according to the molar ratio of the o-toluidine to the absolute ethyl alcohol of 1: 2.2-2.8, stirring and uniformly mixing, adjusting the pH value of the solution to 2.5 by using sulfuric acid, then completely pressing the materials into an alkylation kettle by using nitrogen, adding magnetic solid acid into the alkylation kettle, stirring uniformly, sealing the kettle, slowly heating to 60-120 ℃ within 5 hours, then reacting for 8-15 hours under the conditions of 60-120 ℃ and stirring, ending the reaction, pressing the materials into a separation kettle, cooling to 40 ℃ by using circulating water, collecting the magnetic solid acid in the alkylation kettle by using a magnetic separation device, then dropwise adding a KOH solution with the mass concentration of 60-80% into the separation kettle, adjusting the pH value to 7.0, heating the materials in the kettle by using steam, evaporating unreacted ethyl alcohol, and when the temperature is increased to 95-100 ℃, no fraction is generated, and (5) ending distillation to obtain an alkylate mixture.

3. The process for producing basic red intermediate 3-ethylamino p-methylphenol according to claim 2, wherein,

the magnetic solid acid adopts SO4^2-/ZrO₂/Fe₃O₄、Al₂O₃/Fe₃O₄。

4. The process for producing basic red intermediate 3-ethylamino p-methylphenol as claimed in claim 2, wherein the magnetic solid acid is selected from the group consisting of sodium hydroxide, potassium hydroxideAnd (3) heating the alkylation kettle to 60-80 ℃, carrying out alkylation reaction for 6-8 hours at 60-80 ℃, and applying an external magnetic field in the temperature control reaction process.

5. The process for producing basic red intermediate 3-ethylamino p-methylphenol according to claim 4, wherein the external magnetic field is applied at a strength of 500-600 oe.

6. The production process of the basic red intermediate 3-ethylamino p-methylphenol according to claim 1, characterized in that the specific operation steps of the rectification in step 1 are: and transferring the alkylate mixture to a rectifying tower kettle, rectifying the alkylate mixture by a rectifying tower, and collecting main fraction, namely the refined N-ethyl-o-toluidine.

7. The process for producing basic red intermediate 3-ethylamino p-methylphenol according to claim 1,

the specific operation steps of the sulfonation reaction in the step 2 are as follows: adding fuming sulfuric acid into a sulfonation kettle according to the molar mass ratio of N-ethyl o-toluidine to fuming sulfuric acid of 1: 1.8-2.2, then slowly dropwise adding N-ethyl o-toluidine at the dropping speed of 22-28 kg/h, strictly controlling the temperature in the sulfonation kettle to be less than or equal to 50 ℃ in the dropwise adding process, after dropwise adding is finished, pressing the material into a heat preservation kettle by using nitrogen, preserving the heat for 5-8 h at the temperature of 60-70 ℃, then pressing the material into a dilution kettle by using nitrogen, wherein water and ice blocks are arranged in the dilution kettle in advance, so that the pressed material can be reduced to be below 20 ℃, crystallizing and separating out the sulfonation reaction product 3-ethylamino p-toluenesulfonic acid, and carrying out centrifugal separation to obtain a filter cake A, namely 3-ethylamino p-toluenesulfonic acid, and conveying the filter cake to an alkali fusion kettle.

8. The process for producing basic red intermediate 3-ethylamino p-methylphenol according to claim 1,

the specific operation steps of hydroxylation in step 3 are as follows: adding potassium hydroxide and water into an alkali fusion kettle according to the mass ratio of the 3-ethylamino p-toluenesulfonic acid to the potassium hydroxide to the water of 1: 5.0-5.5: 4.0-4.5, heating to over 200 ℃, adding 3-ethylamino p-toluenesulfonic acid crystals in batches, controlling the alkali fusion kettle to be at 220-300 ℃, carrying out heat preservation reaction for 60-80 hours, and finishing the reaction.

9. The process for producing basic red intermediate 3-ethylamino p-methylphenol according to claim 1,

step 4 the concrete operation steps of acid precipitation are as follows: adding the material after the hydroxylation reaction into an acid precipitation kettle, then supplementing 20-28 mol of water, controlling the reaction temperature below 40 ℃, dropwise adding hydrochloric acid, finishing the reaction when the PH reaches 7.0-7.5, crystallizing and separating out 3-ethylamino p-cresol, filtering to obtain a filter cake B, and distilling and purifying the filter cake B to obtain the 3-ethylamino p-methylphenol.

Technical Field

The invention belongs to the field of material surface treatment, and particularly relates to a production process of an alkaline red intermediate 3-ethylamino p-methylphenol.

Background

The alkaline red intermediate 3-ethylaminoparacresol is mainly used as a coloring agent in the production process of high-grade ink and paint, and can increase the aging resistance of the product.

The existing preparation method of the alkaline red intermediate 3-ethylaminoparacresol mainly comprises the following steps:

process for alkylation

Raw materials o-toluidine and absolute ethyl alcohol are subjected to alkylation reaction at high temperature under the catalysis of concentrated sulfuric acid to generate a main product N-ethyl o-toluidine, and the reaction equation is as follows:

in addition to the main product N-ethyl-o-toluidine, the present stage also produces by-products, such as N, N, -diethyl-o-toluidine, diethyl ether, etc. The alkylated product was distilled under reduced pressure to obtain N-ethyl-o-toluidine with a content of 98% (referred to as main fraction).

Preparation of sulfonated

3-ethyl amino p-methyl benzene sulfonic acid (sulfonate for short) is produced by sulfonation reaction of the main fraction and 20% oleum, and the reaction equation is as follows:

alkali fusion (i.e. hydroxylation)

And (2) carrying out hydroxylation reaction on the sulfonated substance and hydroxide (the hydroxide refers to sodium hydroxide and potassium hydroxide with the molar ratio of 1: 2.3-3.0) at the high temperature of about 240 ℃, stirring the reactants while reacting at the stirring speed of 65rpm/min, carrying out acid washing neutralization on the product 3-ethylamino p-cresol (referred to as an intermediate for short) by using hydrochloric acid after reacting for 80 hours, and distilling to obtain the target product. The chemical equation is as follows:

the main problems are as follows: (1) the alkylation reaction takes concentrated sulfuric acid as a catalyst, so that the catalyst has high corrosivity and high requirements on equipment, the concentrated sulfuric acid cannot be recovered after the catalysis is finished, the reagent is seriously wasted, the cost is high, (2) the selectivity of the alkylation reaction is poor, byproducts are generated besides the target product N-ethyl-o-toluidine, such as the generation of N, N, -diethyl-o-toluidine, ether and the like, and the yield of the target product is low; (3) the reaction is usually carried out at a temperature of 200 ℃ or above, and the energy consumption is high.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provide a production process of a basic red intermediate 3-ethylamino-p-methylphenol.

In order to achieve the purpose, the technical scheme adopted by the invention is as follows:

a production process of an alkaline red intermediate 3-ethylaminop-methylphenol specifically comprises the following steps:

step 1, alkylation reaction: carrying out alkylation reaction on o-toluidine and absolute ethyl alcohol under the action of a catalyst magnetic solid acid to generate an alkylate mixture, and then placing the alkylate mixture into a rectifying still for rectifying to obtain N-ethyl o-toluidine; the reaction temperature of the alkylation reaction is 60-120 ℃;

the addition amount of the magnetic solid acid is 4-6% of the mass ratio of the feed liquid;

step 2, sulfonation reaction: the N-ethyl o-toluidine and fuming sulfuric acid are subjected to sulfonation reaction to generate 3-ethylamino p-toluenesulfonic acid;

step 3, hydroxylation reaction: hydroxylating 3-ethylaminopara-toluenesulfonic acid with potassium hydroxide to generate 3-ethylaminopara-methylphenol potassium salt;

step 4, acid precipitation: 3-ethylaminop-methylphenol potassium salt reacts with hydrochloric acid to prepare 3-ethylaminop-methylphenol.

Further, the alkylation reaction of step 1 comprises the following specific steps: adding o-toluidine and absolute ethyl alcohol into a pulping kettle according to the molar ratio of the o-toluidine to the absolute ethyl alcohol of 1: 2.2-2.8, stirring and uniformly mixing, adjusting the pH value of the solution to 2.5 by using sulfuric acid, then completely pressing the materials into an alkylation kettle by using nitrogen, adding magnetic solid acid into the alkylation kettle, stirring uniformly, sealing the kettle, slowly heating to 60-120 ℃ within 5 hours, then reacting for 8-15 hours under the conditions of 60-120 ℃ and stirring, ending the reaction, pressing the materials into a separation kettle, cooling to 40 ℃ by using circulating water, collecting the magnetic solid acid in the alkylation kettle by using a magnetic separation device, then dropwise adding a KOH solution with the mass concentration of 60-80% into the separation kettle, adjusting the pH value to 7.0, heating the materials in the kettle by using steam, evaporating unreacted ethyl alcohol, and when the temperature is increased to 95-100 ℃, no fraction is generated, after the distillation is finished, obtaining an alkylate mixture;

further, the magnetic solid acid is SO4^2-/ZrO₂/Fe₃O₄、Al₂O₃/Fe₃O₄。

Further, the magnetic solid acid is usedAnd (3) heating the alkylation kettle to 60-80 ℃, carrying out alkylation reaction for 6-8 hours at 60-80 ℃, and applying an external magnetic field in the temperature control reaction process.

Further, the strength of the applied external magnetic field is 500-600 oe.

Further, the specific operation steps of the rectification in the step 1 are as follows: and transferring the alkylate mixture to a rectifying tower kettle, rectifying the alkylate mixture by a rectifying tower, and collecting main fraction, namely the refined N-ethyl-o-toluidine.

Further, the sulfonation reaction in step 2 comprises the following specific operation steps: adding fuming sulfuric acid into a sulfonation kettle according to the molar mass ratio of N-ethyl o-toluidine to fuming sulfuric acid of 1: 1.8-2.2, then slowly dropwise adding N-ethyl o-toluidine at the dropping speed of 22-28 kg/h, strictly controlling the temperature in the sulfonation kettle to be less than or equal to 50 ℃ in the dropwise adding process, after dropwise adding is finished, pressing the material into a heat preservation kettle by using nitrogen, preserving the heat for 5-8 h at the temperature of 60-70 ℃, then pressing the material into a dilution kettle by using nitrogen, wherein water and ice blocks are pre-arranged in the dilution kettle, so that the pressed material can be reduced to be below 20 ℃, crystallizing and separating out a sulfonation reaction product 3-ethylamino p-toluenesulfonic acid, performing centrifugal separation to obtain a filter cake A, namely 3-ethylamino p-toluenesulfonic acid, and sending the filter cake A into an alkali fusion kettle;

further, the specific operation steps of hydroxylation in step 3 are as follows: adding potassium hydroxide and water into an alkali fusion kettle according to the mass ratio of the 3-ethylamino p-toluenesulfonic acid to the potassium hydroxide to the water of 1: 5.0-5.5: 4.0-4.5, heating to more than 200 ℃, adding 3-ethylamino p-toluenesulfonic acid crystals in batches, controlling the alkali fusion kettle at 220-300 ℃, carrying out heat preservation reaction for 60-80 hours, and finishing the reaction;

further, the specific operation steps of the acid precipitation in the step 4 are as follows: adding the material after the hydroxylation reaction into an acid precipitation kettle, then supplementing 20-28 mol of water, controlling the reaction temperature below 40 ℃, dropwise adding hydrochloric acid, finishing the reaction when the pH value reaches 7.0-7.5, crystallizing and separating out 3-ethylamino p-cresol, filtering to obtain a filter cake B, and distilling and purifying the filter cake B to obtain the 3-ethylamino p-methylphenol.

The alkaline red intermediate 3-ethylaminoparacresol is widely applied as a coloring agent, but the preparation method of the alkaline red intermediate 3-ethylaminoparacresol has the problems of long reaction time, low yield and high energy consumption, and how to search for more favorable productsIn the years of advocating green environmental protection, and in view of the energy-saving and high-efficiency concept, the inventors of the present application try to catalyze the reaction by using other catalysts except concentrated sulfuric acid, such as zinc chloride, magnesium chloride and aluminum oxide, which unfortunately cannot achieve satisfactory catalytic effects, and when the invention is about to be abandoned, the preparation method of saving energy, simplifying equipment, shortening process flow and improving product yield is always a hotspot researched by the industry people, and in the years of advocating green environmental protection, the inventors of the present application try to use other catalysts except concentrated sulfuric acid, such as zinc chloride, magnesium chloride and aluminum oxide, and: using magnetic solid acids SO₄ ^2-/ZrO₂/Fe₃O₄The present inventors have made intensive studies on a magnetic solid acid catalyst, and have completed the present invention,

in the search, it was found that not all magnetic solid acids in the reaction are capable of catalyzing the N-alkylation reaction, but only the solid acid is SO₄ ^2-/ZrO₂、Al₂O₃The magnetic solid acid can catalyze N-alkylation, but in the research, the magnetic solid acid can catalyze N-alkylation reaction, but in the alkylation mixture, the yield of N-ethyl o-toluidine is only 22-35%, while the yield of the byproduct N, N, -diethyl o-toluidine is as high as 60-70%, and the research is in a stagnant state once, however, the company needs to prepare a batch of N, N, -diethyl o-toluidine due to the research requirement, so the inventor uses a magnetic catalyst Al₂O₃/Fe₃O₄The catalyst is used for preparing N, N-diethyl o-toluidine by taking o-toluidine and absolute ethanol as raw materials, and the method is as follows: surprisingly, the inventors discovered that the content of N-ethyl-o-toluidine in the alkylate mixture is significantly increased and the content of N, -diethyl-o-toluidine in the alkylate mixture is significantly decreased under the influence of the external magnetic field, compared with the previous research, and then the inventors conducted a great deal of research again on the magnetic solid acid catalyst, and discovered that the magnetic solid acid catalyst is subjected to the external magnetic fieldIn the case of a field, the field,has high selectivity for catalyzing the generation of N-ethyl o-toluidine, and the inventor is happy with the discovery and finds the magnetic catalystThe amount of (2) and the intensity of the applied magnetic field have a direct influence on the reaction by adjusting the magnetic catalystThe addition amount of the magnetic field and the strength of the external magnetic field are 500-600 oe, so that the reaction rate can be obviously improved, and the reaction time can be shortened.

Compared with the prior art, the invention has the following beneficial effects:

the invention provides a novel process for producing 3-ethylamino p-methylphenol for the first time, and provides a new idea for the selective research of N-alkylation reaction in the industry.

In the process of synthesizing the 3-ethylaminopara-methylphenol by adopting the method, the N alkylation reaction has high selectivity, so that the yield of the target product is greatly improved, and compared with the traditional production process, the method shortens the reaction time of the alkylation reaction, reduces the reaction temperature of the alkylation reaction, improves the production efficiency, and can recycle the recovered magnetic solid acid catalyst and reduce the production cost.

Detailed Description

The production process of the present invention is specifically exemplified below

The structural formula of the fuming sulfuric acid used in each example of the invention and the comparative example is: h₂SO₄·SO₃。

The catalytic solid acid used in the invention is prepared by the following method:

1. catalyst magnetic solid acidThe preparation method comprises the following steps:

step (1) of preparing SrFe by adopting a coprecipitation method₁₂O₁₉: SrCO is weighed according to the mol ratio of nSr to nFe of 1 to 10.85₃And FeC₁₃·6H₂O; then, SrCO₃Firstly adding hydrochloric acid to prepare SrC₁₂Dissolving in solution, taking FeC₁₃·6H₂Dissolving O in water, and regulating FeC with NaOH solution₁₃And SrC₁₂Filtering the brown precipitate, and drying the precipitate to obtain a ferrite precursor; then, roasting the precursor at the high temperature of 1000 ℃ for 2h, taking out the precursor, grinding the product into powder to obtain the magnetic matrix SrFe₁₂O₁₉。

Step (2), preparing the strontium magnetic solid acid catalyst by a dipping-roasting method: accurately weighing SrFe according to the mol ratio of nSr to nZr of 1 to 1.5₁₂O₁₉And ZrOC₁₂·8H₂Adding water, stirring for dissolving, slowly dropwise adding precipitator ammonia water until the pH value of the solution is about 9, aging the obtained precipitate at 70 ℃ for 0.5h, stirring for 0.5h, standing for 12h, filtering, and washing the mixed precipitate with deionized water until no Cl & lt- & gt is detected in the filtrate by using 0.1mol/L silver nitrate solution; the resulting cake-like mixed precipitate was dried at 110 ℃ for 12h with 0.5mol/L (NH)₄)₂S₂O₈Soaking in the solution for 4h, drying, and roasting at 550 deg.C for 5h to obtain the final productA catalyst.

2. Catalyst magnetic solid acid Al₂O₃/Fe₃O₄The preparation method comprises the following steps:

step (1), magnetic substrate Fe₃O₄The preparation of (1): FeCl is added₃·6H₂O and FeSO₄·7H₂Dissolving O in deionized water, mixing, placing in a 65 deg.C constant temperature water bath, rapidly stirring while adding 2mol/L NaOH solution to adjust pH to 11, stirring and adding anhydrous ethanol, standing for about 10min until black granules are observed, collecting black granules, washing until no Cl-and SO-exist₄ ^2-Drying to obtain the nano Fe₃O₄Magnetic particles; .

Step (2), preparation of magnetic solid acid: mixing prepared AlCl₃Aqueous solution and magnetic matrix Fe₃O₄Adding into a full-back mixed liquid membrane reactor, adding ammonia water solution after full contact, continuing to react for 2min until the pH value is 12, transferring the solution into a three-neck flask, continuing stirring and aging for 3h in a 75 ℃ constant temperature water bath, centrifugally washing until no Cl & lt- & gt exists, reducing the pH value of the solution to 7, centrifugally separating, drying the precipitate at 100 ℃, taking out, grinding, and roasting in a muffle furnace for a period of time to obtain the offwhite magnetic Al₂O₃A solid acid which exhibits magnetic properties under the action of a magnetic field.

3. The preparation method of the catalyst magnetic solid acid SO42-/ZrO2/Fe3O4 comprises the following steps:

step (1) FeCl₃·6H₂O and FeSO₄·7H₂Dissolving O in deionized water, mixing, placing in a 65 deg.C constant temperature water bath, rapidly stirring while adding 2mol/L NaOH solution to adjust pH to 11, stirring and adding anhydrous ethanol, standing for about 10min until black granules are observed, collecting black granules, washing until no Cl is observed^-And SO₄ ^2-Drying to obtain the nano Fe₃O₄Magnetic particles;

step (2), Fe₃O₄Preparation of the suspension:

2.32g (0.01mol) of nano Fe is added into a three-neck flask₃O₄The magnetic particles are modified by adding 100mL of 0.5mol/L sodium citrate solution in order to increase the dispersibility of the magnetic particles in water, so that the preparation of a coprecipitation carrier in the next step is facilitated, the magnetic particles are heated in a water bath at 60 ℃ under the condition of continuously introducing nitrogen, are mechanically stirred for 12 hours, are subjected to centrifugal separation, and are washed by acetone and deionized water for multiple times to remove the residual sodium citrate solution; then, the modified Fe₃O₄Adding into a beaker filled with 100mL of deionized water, and ultrasonically dispersing for 30min to obtain Fe₃O₄And (3) suspension.

Step (3), ZrO₂/Fe₃O₄Preparation of the support：

Mixing the above 100mL of Fe₃O₄Suspension and 32.20g of ZrOCl₂·8H₂Adding O into 500mL of mixed solution of ethanol and deionized water (volume ratio is 1: 1), heating at 70 ℃, and dropwise adding ammonia water under rapid stirring until the pH value is about 10; standing at 5 deg.C for aging for 12h, filtering, washing with water until no Cl^-(by AgNO)₃Checking), drying in an oven at 110 ℃ to obtain ZrO₂/Fe₃O₄And (3) a carrier.

Step (4), SO₄ ^2-/Fe₃O₄/ZrO₂Preparation of the catalyst

ZrO2 is mixed with₂/Fe₃O₄Grinding and sieving carrier powder, soaking with 3mol/L concentrated sulfuric acid at a liquid-solid ratio of 5 mL: 1g, and roasting at 600 deg.C in a muffle furnace to obtain magnetic solid acid catalyst SO₄ ^2-/ZrO₂/Fe₃O₄And then standby.

4. Catalyst magnetic solid acid Fe₃O₄/C-SO₃The preparation method of H comprises the following steps:

step (1), magnetic Fe₃O₄The preparation of (1): magnetic Fe₃O₄The preparation adopts a coprecipitation method to mix FeCl₃·6H₂O and FeSO₄·7H₂Dissolving O in deionized water, uniformly mixing, placing in a constant-temperature water bath kettle at 65 ℃, quickly stirring while dropwise adding 2mol/L NaOH solution to adjust the pH value to 11, continuously stirring and adding absolute ethyl alcohol, and standing for about 10min until small black particles can be observed; heating to 80 ℃, adding glacial acetic acid to adjust the pH value of the solution to 5, adding anionic surfactant sodium oleate while stirring for surface modification, adsorbing and precipitating by using a magnet after reaction, washing precipitates alternately by using absolute ethyl alcohol and deionized water for multiple times, drying and calcining to obtain magnetic Fe₃O₄。

Step (2) magnetic carbon-based solid acid catalyst Fe₃O₄/C-SO₃H, preparation: magnetic Fe to be prepared₃O₄Grinding, mixing with anhydrous glucose, carbonizing at constant temperature under N2 atmosphere, and cooling to room temperatureHeating to obtain magnetic carbon material Fe₃O₄C; taking the prepared carbon material Fe₃O₄Sulfonating in concentrated sulfuric acid, vacuum filtering to obtain solid, washing with 80 deg.C hot water, adsorbing with magnet, and precipitating until filtrate is clear and free of SO₄ ^2-Drying at 80 ℃ until the magnetic solid acid catalyst Fe is detected₃O₄/C-SO₃H；

5. Catalyst magnetic solid acid TFOH/SiO₂/Fe₃O₄The preparation method comprises the following steps:

step (1), magnetic Fe₃O₄The preparation of (1): FeSO (ferric oxide) is added₄·7H₂Preparing 0.1mol/L solution from O, taking 200mL of the solution, transferring the solution into a 500mL three-neck flask, dropwise adding a small amount of oleic acid, placing the three-neck flask into a 40 ℃ water bath kettle, mechanically stirring at a high speed, and rapidly adding NaOH or concentrated ammonia water to the pH value>9, stirring and reacting for 30 min; after the reaction is finished, carrying out magnetic separation by using a magnet, cleaning the collected product by using deionized water for 3 times, cleaning the product by using absolute ethyl alcohol for 3 to 5 times, and carrying out vacuum drying at the temperature of 60 ℃ for 4 hours to obtain the nano Fe₃O₄Magnetic particles;

step (2), the prepared nano Fe₃O₄Dispersing the magnetic particles in 100mL of dilute hydrochloric acid, and carrying out ultrasonic treatment for 10-15min to enable the nano Fe₃O₄The magnetic particles are completely dispersed. Magnetic separation, washing with deionized water and anhydrous ethanol for 3-5 times, and washing with Fe₃O₄Redispersion in 200mL 1:1, mechanically stirring, adding 3mL of concentrated ammonia water and 0.2mL of TEOS in sequence after 3-5min, and reacting for 10-12h at room temperature. After the reaction is finished, performing magnetic separation and filtration, washing for 3-5 times by using absolute ethyl alcohol, and then diffusing in 200mL of a solution with the volume ratio of 1:1, mechanically stirring the mixture in absolute ethyl alcohol and deionized water, adding 0.5g CTAB after 10min, stirring the mixture for 20min, sequentially adding 3mL of ammonia water and slowly dropwise adding 0.5mL of TEOS, reacting at room temperature, after 10 to 12h, washing the mixture for 2 to 3 times by using deionized water for magnetic separation, washing the mixture for 2 to 3 times by using absolute ethyl alcohol, and performing vacuum drying at 60 ℃ for 12 h; the prepared solid was added to 150mL of ammonium nitrate ethanolic solution (NH)₄NO₃/C₂H₅OH, 6g/L) is condensed and refluxed for 4 hours at 60 ℃,magnetic separation, washing with deionized water for 2-3 times, vacuum drying at 60 deg.C for 4 hr to obtain SiO₂Coated with Fe₃O₄The core-shell structure magnetic carrier of (1);

step (3) CF₃SO₃H/SiO₂/Fe₃O₄Preparation of the catalyst: 0.5g of SiO₂/Fe₃O₄Dispersing in 20mL toluene solvent, ultrasonic treating for 15min, magnetically separating, dispersing in 50mL toluene solvent, water bathing at 90 deg.C, condensing, refluxing, introducing nitrogen for protection, and adding 0.3mL CF dropwise₃SO₃H, reacting for 4H, magnetically separating, washing with toluene for 3-5 times, and vacuum drying at 60 ℃ for 12H. Activated at 300 ℃ in a tube furnace to prepare the CF₃SO₃H/SiO₂/Fe₃O₄(MTFOH) catalyst.

Example 1

A production process of an alkaline red intermediate 3-ethylaminop-methylphenol specifically comprises the following steps:

step 1, alkylation reaction: carrying out alkylation reaction on o-toluidine and absolute ethyl alcohol under the action of a catalyst magnetic solid acid to generate an alkylate mixture, and then placing the alkylate mixture into a rectifying still for rectifying to obtain N-ethyl o-toluidine; the alkylation reaction comprises the following specific steps: adding 625Kg of O-toluidine and 680Kg of anhydrous ethanol into a pulping kettle according to the molar ratio of the O-toluidine to the anhydrous ethanol of 1:2.53, stirring and uniformly mixing, regulating the pH value of the solution to 2.5 by using sulfuric acid, then completely pressing the materials into an alkylation kettle by using nitrogen, adding a magnetic solid acid Al2O3/Fe3O 459 Kg into the alkylation kettle according to the mass concentration of 4.5%, stirring uniformly, sealing the kettle, slowly heating to 70 ℃ within 3 hours, then applying an external magnetic field with the strength of 550oe, reacting for 6 hours at the temperature of 70 ℃, finishing the reaction, pressing the materials into a separation kettle, cooling to 40 ℃ by using circulating water, collecting the magnetic solid acid in the alkylation kettle by using a magnetic separation device, then dropwise adding a KOH solution with the mass concentration of 70% into the separation kettle, regulating the pH value to 7.0, heating the materials in the kettle by using steam, and distilling the unreacted ethanol out, when the temperature rises to 95-100 ℃, no fraction is generated, and the distillation is finished, so that an alkylate mixture is obtained; transferring the alkylate mixture to a rectifying tower kettle, rectifying the alkylate mixture by a rectifying tower, and collecting main fraction to obtain 727Kg of refined N-ethyl-o-toluidine, wherein in the alkylation reaction, the yield of the N-ethyl-o-toluidine is 92.2 percent, and the purity of the refined N-ethyl-o-toluidine is 99.5 percent;

step 2, sulfonation reaction: the N-ethyl o-toluidine and fuming sulfuric acid are subjected to sulfonation reaction to generate 3-ethylamino p-toluenesulfonic acid;

the specific operation steps of the sulfonation reaction are as follows: adding 1876Kg of oleum into a sulfonation kettle according to the molar mass ratio of 1:1.96 of N-ethyl-o-toluidine to oleum, then slowly dripping 727Kg of N-ethyl o-toluidine at the dripping speed of 22-28 Kg/h, strictly controlling the temperature in the sulfonation kettle to be less than or equal to 50 ℃ in the dripping process, after the dripping is finished, pressing the material into a heat preservation kettle by using nitrogen, preserving the heat at 65 ℃ for 6h, then pressing the material into a dilution kettle by using nitrogen, wherein water and ice blocks are placed in the dilution kettle in advance, the temperature of the pressed material can be reduced to be below 20 ℃, a sulfonation reaction product 3-ethylamino p-toluenesulfonic acid is crystallized and separated out, and a filtrate A and a filter cake A are obtained through centrifugal separation, the filtrate A is a dilute sulfuric acid solution with the content of 30 percent and is discharged into a storage tank for treatment, and the filter cake A is 3-ethylamino p-toluenesulfonic acid and is sent to an alkali melting kettle; 1004Kg of 3-ethylamino-p-toluenesulfonic acid is obtained in the step;

step 3, hydroxylation reaction: hydroxylating 3-ethylaminopara-toluenesulfonic acid with potassium hydroxide to generate 3-ethylaminopara-methylphenol potassium salt;

the specific operation steps of the hydroxylation are as follows: adding 1365Kg of potassium hydroxide and 351Kg of water into an alkali fusion kettle according to the mass ratio of the 3-ethylamino p-toluenesulfonic acid to the potassium hydroxide to the water of 1:5.22:4.19, heating to 240 ℃, adding 3-ethylamino p-toluenesulfonic acid crystals in batches, controlling the alkali fusion kettle to 240 ℃, keeping the temperature and reacting for 75 hours, and finishing the reaction;

step 4, acid precipitation: 3-ethylaminop-methylphenol potassium salt reacts with hydrochloric acid to prepare 3-ethylaminop-methylphenol;

the concrete operation steps of the acid precipitation are as follows: adding the material after the hydroxylation reaction into an acid precipitation kettle, adding 27mol of water, controlling the reaction temperature below 40 ℃, dropwise adding hydrochloric acid, finishing the reaction when the pH reaches 7.0-7.5, crystallizing and separating out 3-ethylaminopara-cresol, filtering to obtain a filtrate B and a filter cake B, collecting the filtrate B, pumping the filtrate B into a high-temperature oxidation device, and recovering potassium salt; and after the filter cake B is distilled and purified, 658Kg of 3-ethylamino p-methylphenol is obtained.

In the whole production process, the yield of the 3-ethylamino-p-methylphenol is 75%, and the purity of the prepared 3-ethylamino-p-methylphenol is 95% through detection.

Example 2

A production process of an alkaline red intermediate 3-ethylaminop-methylphenol specifically comprises the following steps:

step 1, alkylation reaction: performing alkylation reaction on o-toluidine and absolute ethyl alcohol under the action of a catalyst magnetic solid acid to generate an alkylate mixture; then placing the alkylate mixture in a rectifying still, and rectifying to obtain N-ethyl o-toluidine; the alkylation reaction comprises the following specific steps: adding 625Kg of o-toluidine and 680Kg of anhydrous ethanol into a pulping kettle according to the molar ratio of the o-toluidine to the anhydrous ethanol of 1:2.53, uniformly stirring, adjusting the pH of the solution to 2.5 by using sulfuric acid, completely pressing the material into an alkylation kettle by using nitrogen, and adding the material into the alkylation kettle according to the mass concentration of 5.0%65Kg of magnetic solid acid is stirred uniformly, the kettle is sealed, the temperature is slowly raised to 70 ℃ within 3 hours, then an external magnetic field with the strength of 500oe is applied, the reaction is finished after 5.5 hours at 75 ℃ under the stirring condition, the material is pressed into a separation kettle, the temperature is lowered to 40 ℃ by adopting circulating water, the magnetic solid acid in the alkylation kettle is collected by adopting a magnetic separation device, then KOH solution with the mass concentration of 70 percent is dripped into the separation kettle, the pH value is adjusted to 7.0, the temperature of the material in the kettle is raised by steam, unreacted ethanol is evaporated, and when the temperature is raised to 95-100 ℃, no fraction is generatedProducing and ending distillation to obtain an alkylate mixture; transferring the alkylate mixture into a rectifying tower kettle, rectifying the alkylate mixture by a rectifying tower, and collecting main fraction to obtain 713Kg of refined N-ethyl-o-toluidine, wherein in the alkylation reaction, the yield of the N-ethyl-o-toluidine is 90.4 percent, and the purity of the refined N-ethyl-o-toluidine is 99.6 percent;

step 2, sulfonation reaction: the N-ethyl o-toluidine and fuming sulfuric acid are subjected to sulfonation reaction to generate 3-ethylamino p-toluenesulfonic acid;

the specific operation steps of the sulfonation reaction are as follows: according to the molar mass ratio of N-ethyl o-toluidine to fuming sulfuric acid of 1:1.96, firstly adding 1839Kg of fuming sulfuric acid into a sulfonation kettle, then slowly dropwise adding 713Kg of N-ethyl o-toluidine at a dropping speed of 24Kg/h, strictly controlling the temperature in the sulfonation kettle to be less than or equal to 50 ℃ in the dropping process, after the dropwise adding is finished, pressing the material into a heat preservation kettle by using nitrogen, preserving the heat for 7h at 60 ℃, then pressing the material into a dilution kettle by using nitrogen, wherein water and ice blocks are arranged in the dilution kettle in advance, the pressed material can be reduced to be below 20 ℃, a sulfonation reaction product, namely 3-ethylamino p-toluenesulfonic acid, is crystallized and separated out, and centrifugally separating a filtrate A and a filter cake A, wherein the filtrate A is a dilute sulfuric acid solution with the content of 30%, and is discharged into a storage tank to be treated, and the filter cake A is 3-ethylamino p-toluenesulfonic acid and is sent to; 979Kg of 3-ethylamino p-toluenesulfonic acid is obtained in the step;

step 3, hydroxylation reaction: hydroxylating 3-ethylaminopara-toluenesulfonic acid with potassium hydroxide to generate 3-ethylaminopara-methylphenol potassium salt;

the specific operation steps of the hydroxylation are as follows: adding 1332Kg of potassium hydroxide and 343Kg of water into an alkali fusion kettle according to the mass ratio of 1:5.22:4.19 of the 3-ethylamino p-toluenesulfonic acid to the potassium hydroxide to the water, heating to 280 ℃, adding 3-ethylamino p-toluenesulfonic acid crystals in batches, controlling the alkali fusion kettle to 280 ℃, keeping the temperature for reacting for 65 hours, and finishing the reaction;

step 4, acid precipitation: 3-ethylaminop-methylphenol potassium salt reacts with hydrochloric acid to prepare 3-ethylaminop-methylphenol;

the concrete operation steps of the acid precipitation are as follows: adding the material after the hydroxylation reaction into an acid precipitation kettle, adding 27mol of water, controlling the reaction temperature below 40 ℃, dropwise adding hydrochloric acid, finishing the reaction when the pH reaches 7.0-7.5, crystallizing and separating out 3-ethylaminopara-cresol, filtering to obtain a filtrate B and a filter cake B, collecting the filtrate B, pumping the filtrate B into a high-temperature oxidation device, and recovering potassium salt; and after the filter cake B is distilled and purified, 639Kg of 3-ethylamino p-methylphenol is obtained.

In the whole production process, the yield of the 3-ethylamino-p-methylphenol is 73%, and the purity of the prepared 3-ethylamino-p-methylphenol is 95% through detection.

Example 3

A production process of an alkaline red intermediate 3-ethylaminop-methylphenol specifically comprises the following steps:

step 1, alkylation reaction: performing alkylation reaction on o-toluidine and absolute ethyl alcohol under the action of a catalyst magnetic solid acid to generate an alkylate mixture; then placing the alkylate mixture in a rectifying still, and rectifying to obtain N-ethyl o-toluidine; the alkylation reaction comprises the following specific steps: adding 625Kg of o-toluidine and 680Kg of anhydrous ethanol into a pulping kettle according to the molar ratio of the o-toluidine to the anhydrous ethanol of 1:2.53, uniformly stirring, adjusting the pH of the solution to 2.5 by using sulfuric acid, completely pressing the material into an alkylation kettle by using nitrogen, and adding magnetic solid acid Al into the alkylation kettle according to the mass concentration of 4.5%₂O₃/Fe₃O₄59Kg, after uniformly stirring, sealing the kettle, slowly heating to 70 ℃ within 3 hours, then applying an external magnetic field with the strength of 500oe, reacting for 6 hours at 70 ℃ under the stirring condition, ending the reaction, pressing the materials into a separation kettle, cooling to 40 ℃ by using circulating water, collecting magnetic solid acid in the alkylation kettle by using a magnetic separation device, then dropwise adding a KOH solution with the mass concentration of 70% into the separation kettle, adjusting the pH to 7.0, heating the materials in the kettle by using steam, evaporating unreacted ethanol, generating no fraction when the temperature is increased to 95-100 ℃, and ending the distillation to obtain an alkylate mixture; the alkylate mixture is transferred to the kettle of a rectifying tower and passes throughRectifying in a rectifying tower, collecting main fraction to obtain 303Kg of refined N-ethyl o-toluidine, wherein in the alkylation reaction, the yield of the N-ethyl o-toluidine is 38.4%, and the purity of the refined N-ethyl o-toluidine is 99.1%;

step 2, sulfonation reaction: the N-ethyl o-toluidine and fuming sulfuric acid are subjected to sulfonation reaction to generate 3-ethylamino p-toluenesulfonic acid;

the specific operation steps of the sulfonation reaction are as follows: adding 781Kg of fuming sulfuric acid into a sulfonation kettle according to the molar mass ratio of N-ethyl o-toluidine to fuming sulfuric acid of 1:1.96, then slowly dropwise adding 303Kg of N-ethyl o-toluidine at the dropwise adding speed of 25Kg/h, strictly controlling the temperature in the sulfonation kettle to be less than or equal to 50 ℃ in the dropwise adding process, after the dropwise adding is finished, pressing the material into a heat preservation kettle by using nitrogen, preserving the heat for 6h at 65 ℃, then pressing the material into a dilution kettle by using nitrogen, wherein water and ice blocks are arranged in the dilution kettle in advance, the pressed material can be reduced to be below 20 ℃, a sulfonation reaction product 3-ethylamino p-toluenesulfonic acid is crystallized and separated out, and centrifugally separating to obtain a filtrate A and a filter cake A, wherein the filtrate A is a dilute sulfuric acid solution with the content of 30 percent and is discharged into a storage tank to be treated, and the filter cake A is 3-ethylamino p-toluenesulfonic acid and is sent to an; 418Kg of 3-ethylamino p-toluenesulfonic acid is obtained in the step;

step 3, hydroxylation reaction: hydroxylating 3-ethylaminopara-toluenesulfonic acid with potassium hydroxide to generate 3-ethylaminopara-methylphenol potassium salt;

the specific operation steps of the hydroxylation are as follows: according to the mass ratio of 3-ethylaminoparatoluenesulfonic acid to potassium hydroxide to water of 1:5.22:4.19, firstly adding 568Kg of potassium hydroxide and 146Kg of water into an alkali melting kettle, then heating to 240 ℃, adding 3-ethylaminoparatoluenesulfonic acid crystals in batches, controlling the alkali melting kettle at 240 ℃, keeping the temperature and reacting for 75 hours, and finishing the reaction;

step 4, acid precipitation: 3-ethylaminop-methylphenol potassium salt reacts with hydrochloric acid to prepare 3-ethylaminop-methylphenol;

the concrete operation steps of the acid precipitation are as follows: adding the material after the hydroxylation reaction into an acid precipitation kettle, adding 27mol of water, controlling the reaction temperature below 40 ℃, dropwise adding hydrochloric acid, finishing the reaction when the pH reaches 7.0-7.5, crystallizing and separating out 3-ethylaminopara-cresol, filtering to obtain a filtrate B and a filter cake B, collecting the filtrate B, pumping the filtrate B into a high-temperature oxidation device, and recovering potassium salt; and distilling and purifying the filter cake B to obtain 274Kg of 3-ethylamino p-methylphenol.

In the whole production process, the yield of the 3-ethylamino-p-methylphenol is 31%, and the purity of the prepared 3-ethylamino-p-methylphenol is 95% through detection.

Example 4

A production process of an alkaline red intermediate 3-ethylaminop-methylphenol specifically comprises the following steps:

step 1, alkylation reaction: carrying out alkylation reaction on o-toluidine and absolute ethyl alcohol under the action of a catalyst magnetic solid acid to generate an alkylate mixture, and then placing the alkylate mixture into a rectifying still for rectifying to obtain N-ethyl o-toluidine; the alkylation reaction comprises the following specific steps: adding 625Kg of o-toluidine and 680Kg of anhydrous ethanol into a pulping kettle according to the molar ratio of the o-toluidine to the anhydrous ethanol of 1:2.53, uniformly stirring, adjusting the pH of the solution to 2.5 by using sulfuric acid, completely pressing the material into an alkylation kettle by using nitrogen, and adding magnetic solid acid SO into the alkylation kettle according to the mass concentration of 4.5%₄ ^2-/ZrO₂/Fe₃O₄59Kg, after uniformly stirring, sealing the kettle, slowly heating to 70 ℃ within 3 hours, then applying an external magnetic field with the strength of 500oe, reacting for 6 hours at 70 ℃ under the stirring condition, ending the reaction, pressing the materials into a separation kettle, cooling to 40 ℃ by using circulating water, collecting magnetic solid acid in the alkylation kettle by using a magnetic separation device, then dropwise adding a KOH solution with the mass concentration of 70% into the separation kettle, adjusting the pH to 7.0, heating the materials in the kettle by using steam, evaporating unreacted ethanol, generating no fraction when the temperature is increased to 95-100 ℃, and ending the distillation to obtain an alkylate mixture; transferring the alkylate mixture into a rectifying tower kettle, rectifying the alkylate mixture by a rectifying tower, and collecting main fraction to obtain refined N-ethyl o-toluidine 313Kg, in the alkylation reaction, the yield of the N-ethyl-o-toluidine is 40%, and the purity of the refined N-ethyl-o-toluidine is 99.4%;

steps 2 to 4 are the same as in example 1;

in the whole production process, the yield of the 3-ethylamino-p-methylphenol is 33%, and the purity of the prepared 3-ethylamino-p-methylphenol is 95% through detection.

Comparative example 1

A production process of an alkaline red intermediate 3-ethylaminop-methylphenol specifically comprises the following steps:

step 1, alkylation reaction: carrying out alkylation reaction on o-toluidine and absolute ethyl alcohol under the action of a catalyst magnetic solid acid to generate an alkylate mixture, and then placing the alkylate mixture into a rectifying still for rectifying to obtain N-ethyl o-toluidine; the alkylation reaction comprises the following specific steps: adding 625Kg of o-toluidine and 680Kg of anhydrous ethanol into a pulping kettle according to the molar ratio of the o-toluidine to the anhydrous ethanol of 1:2.53, uniformly stirring, adjusting the pH of the solution to 2.5 by using sulfuric acid, completely pressing the material into an alkylation kettle by using nitrogen, and adding magnetic solid acid Fe into the alkylation kettle according to the mass concentration of 4.5%₃O₄/C-SO₃H59 Kg, after uniformly stirring, sealing the kettle, slowly heating to 70 ℃ within 3 hours, then applying an external magnetic field with the strength of 500oe, reacting for 6 hours at 70 ℃ under the stirring condition, finishing the reaction, pressing the materials into a separation kettle, cooling to 40 ℃ by using circulating water, collecting magnetic solid acid in the alkylation kettle by using a magnetic separation device, then dropwise adding a KOH solution with the mass concentration of 70% into the separation kettle, regulating the pH to be 7.0, heating the materials in the kettle by using steam, evaporating unreacted ethanol, when the temperature rises to 95-100 ℃, generating no fraction, and finishing the distillation to obtain an alkylate mixture; transferring the alkylate mixture into a rectifying tower kettle, rectifying the alkylate mixture by a rectifying tower, and collecting main fraction to obtain 0Kg of refined N-ethyl-o-toluidine, wherein the yield of the N-ethyl-o-toluidine in the alkylation reaction is 0%;

and 2-4, the process cannot be continued.

Comparative example 2

A production process of an alkaline red intermediate 3-ethylaminop-methylphenol specifically comprises the following steps:

step 1, alkylation reaction: carrying out alkylation reaction on o-toluidine and absolute ethyl alcohol under the action of a catalyst magnetic solid acid to generate an alkylate mixture, and then placing the alkylate mixture into a rectifying still for rectifying to obtain N-ethyl o-toluidine; the alkylation reaction comprises the following specific steps: adding 625Kg of o-toluidine and 680Kg of anhydrous ethanol into a pulping kettle according to the molar ratio of the o-toluidine to the anhydrous ethanol of 1:2.53, uniformly stirring, adjusting the pH of the solution to 2.5 by using sulfuric acid, completely pressing the material into an alkylation kettle by using nitrogen, and adding a magnetic solid acid TFOH/SiO into the alkylation kettle according to the mass concentration of 4.5%₂/Fe₃O₄59Kg, after uniformly stirring, sealing the kettle, slowly heating to 70 ℃ within 3 hours, then applying an external magnetic field with the strength of 500oe, reacting for 6 hours at 70 ℃ under the stirring condition, ending the reaction, pressing the materials into a separation kettle, cooling to 40 ℃ by using circulating water, collecting magnetic solid acid in the alkylation kettle by using a magnetic separation device, then dropwise adding a KOH solution with the mass concentration of 70% into the separation kettle, adjusting the pH to 7.0, heating the materials in the kettle by using steam, evaporating unreacted ethanol, generating no fraction when the temperature is increased to 95-100 ℃, and ending the distillation to obtain an alkylate mixture; transferring the alkylate mixture into a rectifying tower kettle, rectifying the alkylate mixture by a rectifying tower, and collecting main fraction to obtain 0Kg of refined N-ethyl-o-toluidine, wherein the yield of the N-ethyl-o-toluidine in the alkylation reaction is 0%;

and 2-4, the process cannot be continued.

Comparative example 3

A production process of an alkaline red intermediate 3-ethylaminop-methylphenol specifically comprises the following steps:

step 1, alkylation reaction: performing alkylation reaction on o-toluidine and absolute ethyl alcohol under the action of a catalyst magnetic solid acid to generate an alkylate mixture; then the alkylate mixture is placed in a rectifying still for rectification to obtain the N-ethylOrtho-toluidine; the alkylation reaction comprises the following specific steps: adding 625Kg of o-toluidine and 680Kg of anhydrous ethanol into a pulping kettle according to the molar ratio of the o-toluidine to the anhydrous ethanol of 1:2.53, uniformly stirring, adjusting the pH of the solution to 2.5 by using sulfuric acid, completely pressing the material into an alkylation kettle by using nitrogen, and adding the material into the alkylation kettle according to the mass concentration of 4.5%59Kg of magnetic solid acid is stirred uniformly, the kettle is sealed, the temperature is slowly raised to 70 ℃ within 3 hours, then an external magnetic field with the strength of 900oe is applied, the reaction is finished after 6 hours of reaction at 70 ℃ under the stirring condition, the material is pressed into a separation kettle, the temperature is lowered to 40 ℃ by adopting circulating water, the magnetic solid acid in the alkylation kettle is collected by adopting a magnetic separation device, then KOH solution with the mass concentration of 70% is dripped into the separation kettle, the pH value is adjusted to 7.0, the material in the kettle is heated by steam, unreacted ethanol is evaporated, no fraction is generated when the temperature is raised to 95-100 ℃, and the alkylate mixture is obtained after the distillation is finished; transferring the alkylate mixture into a rectifying tower kettle, rectifying the alkylate mixture by a rectifying tower, and collecting main fraction to obtain 385Kg of refined N-ethyl-o-toluidine, wherein in the alkylation reaction, the yield of the N-ethyl-o-toluidine is 48.9 percent, and the purity of the refined N-ethyl-o-toluidine is 99.5 percent;

step 2, sulfonation reaction: the N-ethyl o-toluidine and fuming sulfuric acid are subjected to sulfonation reaction to generate 3-ethylamino p-toluenesulfonic acid;

the specific operation steps of the sulfonation reaction are as follows: according to the molar mass ratio of N-ethyl o-toluidine to fuming sulfuric acid of 1:1.96, firstly adding 995Kg of fuming sulfuric acid into a sulfonation kettle, then slowly dropwise adding 385Kg of N-ethyl o-toluidine at the dropping speed of 25Kg/h, strictly controlling the temperature in the sulfonation kettle to be less than or equal to 50 ℃ in the dropwise adding process, after the dropwise adding is finished, pressing the material into a heat preservation kettle by using nitrogen, preserving the heat for 6h at 65 ℃, then pressing the material into a dilution kettle by using nitrogen, wherein water and ice blocks are arranged in the dilution kettle in advance, the pressed material can be reduced to be below 20 ℃, a sulfonation reaction product, namely 3-ethylamino p-toluenesulfonic acid, is crystallized and separated out, and centrifugally separating to obtain a filtrate A and a filter cake A, wherein the filtrate A is a dilute sulfuric acid solution with the content of 30 percent and is discharged into a storage tank to be treated, and the filter cake A is 3-ethylamino p-toluenesulfonic acid and; 532Kg of 3-ethylamino p-toluenesulfonic acid is obtained in the step;

step 3, hydroxylation reaction: hydroxylating 3-ethylaminopara-toluenesulfonic acid with potassium hydroxide to generate 3-ethylaminopara-methylphenol potassium salt;

the specific operation steps of the hydroxylation are as follows: adding 723Kg of potassium hydroxide and 186Kg of water into an alkali fusion kettle according to the mass ratio of the 3-ethylamino p-toluenesulfonic acid to the potassium hydroxide to the water of 1:5.22:4.19, heating to 240 ℃, adding 3-ethylamino p-toluenesulfonic acid crystals in batches, controlling the alkali fusion kettle to 240 ℃, keeping the temperature and reacting for 75 hours, and finishing the reaction;

step 4, acid precipitation: 3-ethylaminop-methylphenol potassium salt reacts with hydrochloric acid to prepare 3-ethylaminop-methylphenol;

the concrete operation steps of the acid precipitation are as follows: adding the material after the hydroxylation reaction into an acid precipitation kettle, adding 27mol of water, controlling the reaction temperature below 40 ℃, dropwise adding hydrochloric acid, finishing the reaction when the pH reaches 7.0-7.5, crystallizing and separating out 3-ethylaminopara-cresol, filtering to obtain a filtrate B and a filter cake B, collecting the filtrate B, pumping the filtrate B into a high-temperature oxidation device, and recovering potassium salt; and distilling and purifying the filter cake B to obtain 349Kg of 3-ethylamino p-methylphenol.

In the whole production process, the yield of the 3-ethylamino-p-methylphenol is 40%, and the purity of the prepared 3-ethylamino-p-methylphenol is 95% through detection.

Comparative example 4

Step 1, alkylation reaction: performing alkylation reaction on o-toluidine and absolute ethyl alcohol under the action of a catalyst magnetic solid acid to generate an alkylate mixture; then placing the alkylate mixture in a rectifying still, and rectifying to obtain N-ethyl o-toluidine; the alkylation reaction comprises the following specific steps: adding 625Kg of o-toluidine and anhydrous ethanol into a pulping kettle according to the molar ratio of the o-toluidine to the anhydrous ethanol of 1:2.53680Kg of water ethanol, stirring and mixing uniformly, adjusting the pH of the solution to 2.5 by using sulfuric acid, then pressing the materials into an alkylation kettle by using nitrogen, and adding the materials into the alkylation kettle according to the mass concentration of 4.5%59Kg of magnetic solid acid is uniformly stirred, the kettle is sealed, the temperature is slowly raised to 70 ℃ within 3 hours, the reaction is finished after 6 hours of reaction at 70 ℃ under the stirring condition, the material is pressed into a separation kettle, circulating water is adopted to reduce the temperature to 40 ℃, a magnetic separation device is adopted to collect the magnetic solid acid in the alkylation kettle, then, a KOH solution with the mass concentration of 70% is dripped into the separation kettle, after the pH is adjusted to be 7.0, the material in the kettle is heated by steam, unreacted ethanol is evaporated, when the temperature is raised to 95-100 ℃, no fraction is generated, and the distillation is finished, namely an alkylate mixture: transferring the alkylate mixture into a rectifying tower kettle, rectifying the alkylate mixture by a rectifying tower, and collecting main fraction to obtain 225Kg of refined N-ethyl-o-toluidine, wherein in the alkylation reaction, the yield of the N-ethyl-o-toluidine is 28.5%, and the purity of the refined N-ethyl-o-toluidine is 99.1%;

step 2, sulfonation reaction: the N-ethyl o-toluidine and fuming sulfuric acid are subjected to sulfonation reaction to generate 3-ethylamino p-toluenesulfonic acid;

the specific operation steps of the sulfonation reaction are as follows: adding 579Kg of fuming sulfuric acid into a sulfonation kettle according to the molar mass ratio of N-ethyl o-toluidine to fuming sulfuric acid of 1:1.96, then slowly dropwise adding 225Kg of N-ethyl o-toluidine at the dropwise adding speed of 25Kg/h, strictly controlling the temperature in the sulfonation kettle to be less than or equal to 50 ℃ in the dropwise adding process, after dropwise adding is finished, pressing the material into a heat preservation kettle by using nitrogen, preserving the heat for 6h at 65 ℃, then pressing the material into a dilution kettle by using nitrogen, wherein water and ice blocks are arranged in the dilution kettle in advance, the pressed material can be reduced to be below 20 ℃, a sulfonation reaction product 3-ethylamino p-toluenesulfonic acid is crystallized and separated out, and centrifugally separating to obtain a filtrate A and a filter cake A, wherein the filtrate A is a dilute sulfuric acid solution with the content of 30%, and is discharged into a storage tank to be treated, and the filter cake A is 3-ethylamino p-toluenesulfonic acid and is sent to an alkali; 312Kg of 3-ethylamino-p-toluenesulfonic acid is obtained in the step;

step 3, hydroxylation reaction: hydroxylating 3-ethylaminopara-toluenesulfonic acid with potassium hydroxide to generate 3-ethylaminopara-methylphenol potassium salt;

the specific operation steps of the hydroxylation are as follows: according to the mass ratio of 3-ethylaminoparatoluenesulfonic acid to potassium hydroxide to water of 1:5.22:4.19, firstly adding 425Kg of potassium hydroxide and 109Kg of water into an alkali fusion kettle, then heating to 240 ℃, adding 312Kg of 3-ethylaminoparatoluenesulfonic acid crystals in batches, then controlling the alkali fusion kettle at 240 ℃, keeping the temperature and reacting for 75 hours, and finishing the reaction;

step 4, acid precipitation: 3-ethylaminop-methylphenol potassium salt reacts with hydrochloric acid to prepare 3-ethylaminop-methylphenol

The concrete operation steps of the acid precipitation are as follows: adding the material after the hydroxylation reaction into an acid precipitation kettle, adding 27mol of water, controlling the reaction temperature below 40 ℃, dropwise adding hydrochloric acid, finishing the reaction when the pH reaches 7.0-7.5, crystallizing and separating out 3-ethylaminopara-cresol, filtering to obtain a filtrate B and a filter cake B, collecting the filtrate B, pumping the filtrate B into a high-temperature oxidation device, and recovering potassium salt; and distilling and purifying the filter cake B to obtain 204Kg of 3-ethylamino p-methylphenol.

In the whole production process, the yield of the 3-ethylamino-p-methylphenol is 26%, and the purity of the prepared 3-ethylamino-p-methylphenol is 96% through detection.

Comparative example 5

Step 1, alkylation reaction: performing alkylation reaction on o-toluidine and absolute ethyl alcohol under the action of a catalyst magnetic solid acid to generate an alkylate mixture; then placing the alkylate mixture in a rectifying still, and rectifying to obtain N-ethyl o-toluidine; the alkylation reaction comprises the following specific steps: according to the molar ratio of o-toluidine to absolute ethyl alcohol to concentrated sulfuric acid of 1: 2.53: 3.27, adding 625Kg of o-toluidine and 680Kg of absolute ethanol into a pulping kettle, stirring and mixing evenly, controlling the temperature of the pulping kettle to be lower than 50 ℃, dropwise adding 320Kg of concentrated sulfuric acid into the pulping kettle, continuously stirring for 1h, then the materials are completely pressed into the alkylation kettle by nitrogen, the kettle is closed, the temperature is slowly raised to 200 ℃ within 5 hours, the pressure in the kettle is raised to 2MPa at the moment, the reaction is finished after the temperature is kept at 200 ℃ for reaction for 15 hours, the materials are pressed into a neutralization kettle, cooling to 40 ℃ by adopting circulating water, dropwise adding KOH solution with the mass concentration of 30% into a neutralization kettle, adjusting the pH to 7.0, continuing stirring for 1h, then standing for 2h, separating an organic phase from a waste water phase, discharging the waste water, heating the residual materials in the kettle by using steam, evaporating the unreacted ethanol, when the temperature rises to 95-100 ℃, no fraction is generated, and the distillation is finished, so that an alkylate mixture is obtained; transferring the alkylate mixture into a rectifying tower kettle, rectifying the alkylate mixture by a rectifying tower, and collecting main fraction to obtain 620Kg of refined N-ethyl-o-toluidine, wherein in the alkylation reaction, the yield of the N-ethyl-o-toluidine is 83.9 percent, and the purity of the refined N-ethyl-o-toluidine is 99.5 percent;

step 2, sulfonation reaction: the N-ethyl o-toluidine and fuming sulfuric acid are subjected to sulfonation reaction to generate 3-ethylamino p-toluenesulfonic acid;

the specific operation steps of the sulfonation reaction are as follows: adding 1600Kg of fuming sulfuric acid into a sulfonation kettle according to the molar mass ratio of the N-ethyl o-toluidine to the fuming sulfuric acid of 1:1.96, then slowly dropwise adding 620Kg of the N-ethyl o-toluidine at the dropwise adding speed of 25Kg/h, strictly controlling the temperature in the sulfonation kettle to be less than or equal to 50 ℃ in the dropwise adding process, after the dropwise adding is finished, pressing the material into a heat preservation kettle by using nitrogen, preserving the heat for 6h at 65 ℃, then pressing the material into a dilution kettle by using nitrogen, wherein water and ice blocks are pre-arranged in the dilution kettle, the pressed material can be reduced to be below 20 ℃, a sulfonation reaction product, namely 3-ethylamino p-toluenesulfonic acid, is crystallized and separated out, and centrifugally separating a filtrate A and a filter cake A, wherein the filtrate A is a dilute sulfuric acid solution with the content of 30%, and is discharged into a storage tank to be treated, and the filter cake A is 3-ethylamino p-toluenesulfonic acid and; 856Kg of 3-ethylamino-p-toluenesulfonic acid is obtained in this step;

step 3, hydroxylation reaction: hydroxylating 3-ethylaminopara-toluenesulfonic acid with potassium hydroxide to generate 3-ethylaminopara-methylphenol potassium salt;

the specific operation steps of the hydroxylation are as follows: adding 1165Kg of potassium hydroxide and 300Kg of water into an alkali fusion kettle according to the mass ratio of the 3-ethylamino p-toluenesulfonic acid to the potassium hydroxide to the water of 1:5.22:4.19, heating to 240 ℃, adding 856Kg of 3-ethylamino p-toluenesulfonic acid crystals in batches, controlling the alkali fusion kettle at 240 ℃, keeping the temperature and reacting for 75 hours, and finishing the reaction;

step 4, acid precipitation: 3-ethylaminop-methylphenol potassium salt reacts with hydrochloric acid to prepare 3-ethylaminop-methylphenol;

the concrete operation steps of the acid precipitation are as follows: adding the material after the hydroxylation reaction into an acid precipitation kettle, adding 27mol of water, controlling the reaction temperature below 40 ℃, dropwise adding hydrochloric acid, finishing the reaction when the pH reaches 7.0-7.5, crystallizing and separating out 3-ethylaminopara-cresol, filtering to obtain a filtrate B and a filter cake B, collecting the filtrate B, pumping the filtrate B into a high-temperature oxidation device, and recovering potassium salt; and distilling and purifying the filter cake B to obtain 562Kg of 3-ethylamino p-methylphenol.

In the whole production process, the yield of the 3-ethylamino-p-methylphenol is 64%, and the purity of the prepared 3-ethylamino-p-methylphenol is 95% through detection.

The embodiments described above are only preferred embodiments of the invention and are not exhaustive of the possible implementations of the invention. Any obvious modifications to the above would be obvious to those of ordinary skill in the art, but would not bring the invention so modified beyond the spirit and scope of the present invention.