Catalytic preparation method of parafuchsin

Abstract

The invention belongs to the technical field of para-fuchsin preparation, and particularly relates to a catalytic preparation method of para-fuchsin, which comprises the following steps: adding aniline into carbon tetrachloride, and fully and uniformly stirring to form a mixed solution; adding aluminum chloride into the mixed solution, stirring at low temperature until the aluminum chloride is completely dissolved, then reacting for 4-16 hours in a protective gas atmosphere, adding a sodium hydroxide solution to adjust the pH value, then carrying out azeotropic distillation to obtain a crude product, then sequentially putting the crude product into diethyl ether, continuously stirring, filtering, and washing with diethyl ether for multiple times to obtain a purified product; and adding the purified product into distilled water, heating, stirring, cooling, filtering, airing to obtain a filter cake, adding the filter cake into ethanol, dissolving, filtering, and spray-drying to obtain the product parafuchsin. According to the method disclosed by the invention, the process defects of the existing parafuchsin are overcome, carbon tetrachloride is used as a solvent and a raw material for the first time, 4, 4 ', 4' '-anilino chloromethane is formed under the catalytic action of anhydrous aluminum chloride, and 4, 4', 4 ''-anilino chlorocarbinol, namely alkaline parafuchsin, is directly obtained in an alkalization manner.

Description

Technical Field

[0001] The invention belongs to the technical field of parafuchsin preparation, and particularly relates to a catalytic preparation method of parafuchsin. Background Art

[0002] Paracarmine is a dye that was discovered and prepared as early as the 19th century. Its manufacturing method has been used until now, but the yield of this preparation method is only 30-40%, and it also brings serious pollution of three wastes. With the continuous advancement of technology and the increase in market demand for this dye, many manufacturers have invested a lot of manpower and material resources in researching new processes, but none of them are mature. Therefore, manufacturers continue to use the old process market. Summary of the invention

[0003] In view of the problems in the prior art, the present invention provides a catalytic preparation method of para-purple, which solves the process defects of the existing para-purple, uses carbon tetrachloride as a solvent and a raw material for the first time, forms 4,4',4"-anilinochloromethane under the catalytic action of anhydrous aluminum chloride, and directly obtains 4,4',4"-anilinochloromethanol by alkalization, that is, basic para-purple.

[0004] In order to achieve the above technical objectives, the technical solution of the present invention is:

[0005] A catalytic preparation method of parafuchsin comprises the following steps:

[0006] Step 1, adding aniline to carbon tetrachloride and stirring well to form a mixed solution, wherein the molar ratio of aniline to carbon tetrachloride is 3:1, the stirring speed is 300-500 r / min, and the stirring temperature is 10-20° C.;

[0007] Step 2, adding aluminum chloride to the mixed solution and stirring at low temperature until completely dissolved, then reacting for 4-16 hours under a protective gas atmosphere, adjusting the pH to form a slurry, the mass ratio of aluminum chloride to the mixed solution is 1-3:10, the stirring speed of low-temperature stirring is 100-400r / min, and the temperature is 5-10°C; the protective gas atmosphere adopts a nitrogen atmosphere, and the reaction temperature is 30-50°C; the pH is adjusted using a sodium hydroxide solution, and the concentration of the sodium hydroxide solution is 0.1-0.4mol / L, and the pH after the pH is adjusted is 8-8.5,

[0008] Step 3, azeotropically distilling the slurry to obtain a crude product, then sequentially placing the crude product into diethyl ether and continuing to stir, filtering and washing with diethyl ether for multiple times to obtain a purified product, wherein the mass ratio of the crude product to diethyl ether is 1:5-8, the stirring speed is 100-300 r / min, and the washing amount of diethyl ether is 100-120% of the quality of the crude product;

[0009] Step 4: Add the purified product to distilled water and heat it up and stir it, cool it down and filter it to dry it to obtain a filter cake, then add the filter cake to ethanol to dissolve it, filter it and spray dry it to obtain the product para-red, the mass ratio of the purified product to distilled water is 1:2-3, the temperature of heating and stirring is 80-90°C; the temperature after cooling is 5-10°C, the concentration of the filter cake in ethanol is 200-400g / L, the spray speed of spray drying is 5-10mL / min, and the area is 80-100cm 2 , the temperature is 80-90℃.

[0010] The reaction mechanism of this process is as follows:

[0011]

[0012] It can be seen from the above description that the present invention has the following advantages:

[0013] 1 The present invention solves the process defects of the existing para-purple red. For the first time, carbon tetrachloride is used as a solvent and a raw material to form 4,4',4"-anilinomethyl chloride under the catalytic action of anhydrous aluminum chloride, and 4,4',4"-anilinomethyl chloride is directly obtained by alkalization, that is, basic para-purple red.

[0014] 2. The present invention utilizes the solubility of aluminum chloride in carbon tetrachloride and aniline to form a homogeneous catalytic system, and simultaneously utilizes the amphoteric property of aluminum salt to form sodium aluminate to achieve separation from the product. DETAILED DESCRIPTION

[0015] The present invention is described in detail with reference to the embodiments, but no limitation is imposed on the claims of the present invention.

[0016] Example 1

[0017] A catalytic preparation method of parafuchsin comprises the following steps:

[0018] Step 1, adding aniline to carbon tetrachloride and stirring well to form a mixed solution, wherein the molar ratio of aniline to carbon tetrachloride is 3:1, the stirring speed is 300 r / min, and the stirring temperature is 10° C.;

[0019] Step 2, adding aluminum chloride to the mixed solution and stirring at low temperature until completely dissolved, then reacting for 4 hours under a protective gas atmosphere, adjusting the pH to form a slurry, the mass ratio of the aluminum chloride to the mixed solution is 1:10, the stirring speed of the low-temperature stirring is 100r / min, and the temperature is 5°C; the protective gas atmosphere adopts a nitrogen atmosphere, and the reaction temperature is 30°C; the pH is adjusted using a sodium hydroxide solution, and the concentration of the sodium hydroxide solution is 0.1mol / L, and the pH after the pH is adjusted is 8;

[0020] Step 3, azeotropically distilling the slurry to obtain a crude product, then sequentially placing the crude product into diethyl ether and continuing to stir, filtering and washing with diethyl ether for multiple times to obtain a purified product, wherein the mass ratio of the crude product to diethyl ether is 1:5, the stirring speed is 100 r / min, and the washing amount of diethyl ether is 100% of the quality of the crude product;

[0021] Step 4: Add the purified product to distilled water and heat it up and stir it, cool it down and filter it to dry it to obtain a filter cake, then add the filter cake to ethanol to dissolve it, filter it and spray dry it to obtain the product para-red, the mass ratio of the purified product to distilled water is 1:2, the temperature of heating and stirring is 80°C; the temperature after cooling is 5°C, the concentration of the filter cake in ethanol is 200g / L, the spray speed of spray drying is 5mL / min, and the area is 80cm 2 , the temperature is 80℃.

[0022] The product of this example is basic para-red, with a yield of 68.1% and a purity of 92.9%. Aluminum chloride is recovered through aluminum hydroxide, with a recovery rate of 98.5%.

[0023] Example 2

[0024] A catalytic preparation method of parafuchsin comprises the following steps:

[0025] Step 1, adding aniline to carbon tetrachloride and stirring well to form a mixed solution, wherein the molar ratio of aniline to carbon tetrachloride is 3:1, the stirring speed is 500 r / min, and the stirring temperature is 20° C.;

[0026] Step 2, adding aluminum chloride to the mixed solution and stirring at low temperature until completely dissolved, then reacting for 16 hours under a protective gas atmosphere, adjusting the pH to form a slurry, the mass ratio of the aluminum chloride to the mixed solution is 3:10, the stirring speed of the low-temperature stirring is 400r / min, and the temperature is 10°C; the protective gas atmosphere adopts a nitrogen atmosphere, and the reaction temperature is 50°C; the pH is adjusted using a sodium hydroxide solution, and the concentration of the sodium hydroxide solution is 0.4mol / L, and the pH after adjusting the pH is 8.5,

[0027] Step 3, azeotropically distilling the slurry to obtain a crude product, then sequentially placing the crude product into diethyl ether and continuing to stir, filtering and washing with diethyl ether for multiple times to obtain a purified product, wherein the mass ratio of the crude product to diethyl ether is 1:8, the stirring speed is 300 r / min, and the washing amount of diethyl ether is 120% of the quality of the crude product;

[0028] Step 4: Add the purified product to distilled water and heat it up and stir it, cool it down and filter it to dry it to obtain a filter cake, then add the filter cake to ethanol to dissolve it, filter it and spray dry it to obtain the product para-red, the mass ratio of the purified product to distilled water is 1:3, the temperature of heating and stirring is 90°C; the temperature after cooling is 10°C, the concentration of the filter cake in ethanol is 400g / L, the spray speed of spray drying is 10mL / min, and the area is 100cm 2 , the temperature is 90℃.

[0029] The product of this example is basic para-red, with a yield of 69.7% and a purity of 94.1%. Aluminum chloride is recovered through aluminum hydroxide, with a recovery rate of 99.3%.

[0030] Example 3

[0031] A catalytic preparation method of parafuchsin comprises the following steps:

[0032] Step 1, adding aniline to carbon tetrachloride and stirring well to form a mixed solution, wherein the molar ratio of aniline to carbon tetrachloride is 3:1, the stirring speed is 400 r / min, and the stirring temperature is 15° C.;

[0033] Step 2, adding aluminum chloride to the mixed solution and stirring at low temperature until completely dissolved, then reacting for 12 hours under a protective gas atmosphere, adjusting the pH to form a slurry, the mass ratio of the aluminum chloride to the mixed solution is 1:5, the stirring speed of the low-temperature stirring is 300r / min, and the temperature is 8°C; the protective gas atmosphere adopts a nitrogen atmosphere, and the reaction temperature is 40°C; the pH is adjusted using a sodium hydroxide solution, and the concentration of the sodium hydroxide solution is 0.3mol / L, and the pH after adjusting the pH is 8,

[0034] Step 3, azeotropically distilling the slurry to obtain a crude product, then sequentially placing the crude product into diethyl ether and continuing to stir, filtering and washing with diethyl ether for multiple times to obtain a purified product, wherein the mass ratio of the crude product to diethyl ether is 1:7, the stirring speed is 200 r / min, and the washing amount of diethyl ether is 110% of the quality of the crude product;

[0035] Step 4: Add the purified product to distilled water and heat it up and stir it, cool it down and filter it to dry it to obtain a filter cake, then add the filter cake to ethanol to dissolve it, filter it and spray dry it to obtain the product para-red, the mass ratio of the purified product to distilled water is 1:3, the temperature of heating and stirring is 85°C; the temperature after cooling is 8°C, the concentration of the filter cake in ethanol is 300g / L, the spray speed of spray drying is 8mL / min, and the area is 90cm 2 , the temperature is 85℃.

[0036] The product of this example is basic para-red, with a yield of 68.9% and a purity of 93.7%. Aluminum chloride is recovered through aluminum hydroxide, with a recovery rate of 98.9%.

[0037] It is understood that the above specific description of the present invention is only used to illustrate the present invention and is not limited to the technical solutions described in the embodiments of the present invention. Those skilled in the art should understand that the present invention can still be modified or replaced by equivalents to achieve the same technical effects; as long as the use requirements are met, they are within the protection scope of the present invention.

Claims

1. A catalytic preparation method of parafuchsin, characterized in that: The steps include: Step 1, adding aniline to carbon tetrachloride and stirring well to form a mixed solution; Step 2: adding aluminum chloride to the mixed solution and stirring at low temperature until completely dissolved, then reacting for 4-16 hours under a protective gas atmosphere, and adjusting the pH to form a slurry. Step 3, azeotropically distilling the slurry to obtain a crude product, then sequentially placing the crude product into ether and continuing to stir, filtering and then washing with ether for multiple times to obtain a purified product; Step 4, adding the purified product to distilled water, heating and stirring, cooling and filtering, and air-drying to obtain a filter cake, then adding the filter cake to ethanol to dissolve, filtering and spray-drying to obtain the product para-red.

2. The catalytic preparation method of parafuchsin according to claim 1, characterized in that: The molar ratio of aniline to carbon tetrachloride in step 1 is 3:1, the stirring speed for uniform stirring is 300-500 r / min, and the stirring temperature is 10-20°C.

3. The catalytic preparation method of parafuchsin according to claim 1, characterized in that: The mass ratio of aluminum chloride to the mixed solution in step 2 is 1-3:10, the stirring speed of low-temperature stirring is 100-400 r / min, and the temperature is 5-10°C.

4. The catalytic preparation method of parafuchsin according to claim 1, characterized in that: The protective gas atmosphere in step 2 is nitrogen atmosphere, and the reaction temperature is 30-50°C.

5. The catalytic preparation method of parafuchsin according to claim 1, characterized in that: In step 2, the pH is adjusted using a sodium hydroxide solution, and the concentration of the sodium hydroxide solution is 0.1-0.4 mol / L, and the pH after the adjustment is 8-8.

5.

6. The catalytic preparation method of parafuchsin according to claim 1, characterized in that: The mass ratio of the crude product to diethyl ether in step 3 is 1:5-8, the stirring speed is 100-300 r / min, and the washing amount of diethyl ether is 100-120% of the quality of the crude product.

7. The catalytic preparation method of parafuchsin according to claim 1, characterized in that: The mass ratio of the purified product to distilled water in step 4 is 1:2-3, the temperature of heating and stirring is 80-90°C; the temperature after cooling is 5-10°C.

8. The catalytic preparation method of parafuchsin according to claim 1, characterized in that: The concentration of the filter cake in step 4 in ethanol is 200-400 g / L, the spray drying spray speed is 5-10 mL / min, and the area is 80-100 cm 2 , the temperature is 80-90℃.

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