Production process of 6-amino-m-cresol

Abstract

The invention discloses a production process of 6-amino-m-cresol, which belongs to the technical field of fine chemical engineering, and comprises the following steps: putting 6-nitro-m-cresol into a reaction kettle, stirring, heating to reflux, adding a part of palladium carbon while stirring, slowly dripping hydrazine hydrate, controlling the temperature to reflux in the dripping process, keeping the temperature for reaction after the dripping is finished, and cooling to room temperature to obtain the 6-amino-m-cresol. Adding residual palladium-carbon for heat preservation reaction, thermally filtering reactants to recover palladium-carbon, and adding filtrate into the reaction kettle for cooling; carrying out suction filtration on the filtrate, then carrying out throwing filtration to obtain a filter cake, ethanol and residues, steaming the obtained residues with ethanol, adding the steamed residues into a reaction kettle, cooling to obtain a wet product 1, and washing the filter cake with water until the filter cake is white to obtain a wet product 2; and mixing and drying the wet product 1 and the wet product 2 to obtain the product. According to the production process of the 6-amino-m-cresol, the product delivery rate can be increased, the safety risk can be reduced, the purity can be ensured, the delivery time is shorter, the operation is simple, the yield can reach 78%, and the purity is 99.8%.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of fine chemical industry, in particular, to a production process of 6-amino-m-cresol. BACKGROUND

[0002] 6-amino-m-cresol has Chinese alias 2-amino-5-methyl phenol, CAS number 2835-98-5, molecular formula C7H9NO, and molecular weight 123.15. 6-amino-m-cresol can be used as dyes, indicators and analytical reagents. 6-amino-m-cresol can be used as DNA and RNA staining agent in biological research. The preservative has antibacterial performance, and 6-amino-m-cresol can also be used as a component of some antibacterial preservatives and safety photographic materials.

[0003] In the prior art, the preparation method of 6-amino-m-cresol is complex in operation and low in yield, therefore, how to develop a production process of 6-amino-m-cresol which is simple in operation and high in yield is a technical problem to be solved by the person skilled in the art. SUMMARY

[0004] Therefore, the present application provides a production process of 6-amino-m-cresol.

[0005] The production process of 6-amino-m-cresol comprises the following steps:

[0006] (1) divide the palladium-carbon into two parts, put 6-nitro-m-cresol into a reaction kettle and stir to heat to reflux, then add a part of the palladium-carbon into the 6-nitro-m-cresol and slowly drop hydrazine hydrate into the 6-nitro-m-cresol, control the temperature to reflux during the dropping of the hydrazine hydrate, after the dropping of the hydrazine hydrate is completed, keep the reaction, then add the remaining palladium-carbon to continue the reaction, and obtain a reaction product;

[0007] (2) heat filter the reaction product obtained in step (1) to recover the palladium-carbon, and add the filter liquor obtained by the heat filtering into the reaction kettle to cool down;

[0008] (3) first suction filter the filter liquor cooled down in step (2), then spin filter to obtain a filter cake, ethanol and a residue, the mass of the ethanol is 2 / 3 of the total mass of the palladium-carbon, 6-nitro-m-cresol and hydrazine hydrate, add the obtained ethanol to the bottom of a steam kettle, and place the obtained residue on a steam shelf of the steam kettle, steam until the ethanol in the bottom of the kettle is completely evaporated, add the residue after the steaming into the reaction kettle to cool down, obtain a wet product 1, and after washing the filter cake with water until it is white, obtain a wet product 2;

[0009] (4) mix and dry the wet product 1 and the wet product 2 obtained in step (3) to obtain 6-amino-m-cresol.

[0010] Further, in step (1), the mass ratio of 6-nitro-m-cresol, hydrazine hydrate, the part of palladium on carbon and the rest of palladium on carbon is 120:110:(2-2.5):0.5.

[0011] Further, in step (1), 6-nitro-m-cresol and palladium on carbon are placed in a reaction kettle and stirred to be heated to 80℃ to reflux, the dropping time of hydrazine hydrate is 5 hours, the temperature is controlled to 70℃ to reflux during the dropping of hydrazine hydrate, after the dropping of hydrazine hydrate is completed, the reaction is kept for 1 hour at 70℃, and then the rest of palladium on carbon is added to continue the reaction until 6-nitro-m-cresol is reacted completely.

[0012] Further, in step (2), the filtrate obtained by hot filtration is added to a reaction kettle and cooled to 5℃.

[0013] Further, in step (3), the distillation residue is cooled to 5℃.

[0014] Further, in step (4), the drying temperature is 70-80℃, and the drying time is 8 hours.

[0015] The present application has the following advantages: the present application adds hydrazine hydrate in batches to ensure the reaction and control the cost, the production process of 6-amino-m-cresol can improve the product delivery rate, reduce the safety risk, ensure the purity, and the delivery time is faster, the operation is simple, the yield can reach 78%, and the purity is 99.8%. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 The HPLC spectrum of 6-amino-m-cresol prepared in Example 1. DETAILED DESCRIPTION

[0017] The technical solutions in the examples of the present application will be described clearly and completely below. Obviously, the described examples are only a part of the examples of the present application, but not all the examples. Based on the examples in the present application, all the other examples obtained by those skilled in the art without creative labor are within the protection scope of the present application.

[0018] Example 1

[0019] The production process of 6-amino-m-cresol includes the following steps:

[0020] (1) Put 120 kg 6-nitro-m-cresol into a reaction kettle and stir to heat to 80°C reflux, then add 2.5 kg palladium-carbon into the 6-nitro-m-cresol and slowly drop 110 kg hydrazine hydrate into the 6-nitro-m-cresol, the stirring speed is 60 r / min, control the temperature to 70°C reflux during the dropping of the hydrazine hydrate, the dropping time of the hydrazine hydrate is 5 hours, after the dropping of the hydrazine hydrate is completed, keep the temperature at 70°C for 1 hour, then add 0.5 kg palladium-carbon and keep the temperature at 70°C for 1 hour, take a sample for analysis, the 6-nitro-m-cresol is reacted completely, and the reaction product is obtained;

[0021] (2) Keep the reaction product obtained in step (1) at a temperature of 300°C and heat to filter to recover the palladium-carbon, and add the filtrate obtained by the heat filtration into a reaction kettle and cool to reduce the temperature to 5°C;

[0022] (3) First suction filter the filtrate after the cooling and temperature reduction in step (2), the pressure of the suction filtration is 20 kPa, then spin filter to obtain a filter cake, ethanol and a residue, the mass of the ethanol is 2 / 3 of the total mass of the palladium-carbon, 6-nitro-m-cresol and hydrazine hydrate, add the obtained ethanol into the bottom of a distillation kettle, and put the obtained residue on the evaporation shelf of the distillation kettle, evaporate the ethanol in the bottom of the distillation kettle completely, add the residue after the evaporation into a reaction kettle and cool to reduce the temperature to 5°C to obtain wet product 1, and wash the filter cake with water until it is white to obtain wet product 2;

[0023] (4) Mix and dry the wet product 1 and the wet product 2 obtained in step (3), the drying temperature is 80°C, and the drying time is 8 hours, to obtain 6-amino-m-cresol, the yield can reach 78%, and the purity is 99.8%.

[0024] The above description of disclosed embodiments enables one of ordinary skill in the art to make or use the application. Various modifications to these embodiments will be readily apparent to those of ordinary skill in the art, and the generic principles defined herein can be applied to other embodiments without departing from the spirit or scope of the application. Thus, the present application is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

The production process of 1.6-amino-meta-cresol is characterized in that: The following steps are involved: (1) palladium carbon is divided into two parts, 6-nitro-meta-cresol is placed in a reaction kettle, stirred and heated to reflux, and then a part of palladium carbon is added to 6-nitro-meta-cresol under stirring, and hydrazine hydrate is slowly dripped into 6-nitro-meta-cresol, and the temperature is controlled to reflux during the dropwise addition of hydrazine hydrate. After the dropwise addition of hydrazine hydrate is completed, the reaction is kept warm, and the remaining palladium carbon is added and the reaction is continued to be kept warm to obtain a reactant; (2) hot filtering the reactant obtained in step (1) to recover palladium on carbon, and adding the filtrate obtained by hot filtration into a reactor to cool down; (3) The filtrate after cooling in step (2) is first sucked and filtered, and then discarded to obtain a filter cake, ethanol and a residue, wherein the mass of the ethanol is 2 / 3 of the total mass of palladium carbon, 6-nitro-meta-cresol and hydrazine hydrate, the obtained ethanol is added to the bottom of a steamer, the obtained residue is placed on a steaming rack of the steamer, and steamed until all the ethanol at the bottom of the steamer is evaporated, the steamed residue is added to a reactor and cooled to obtain a wet product 1, and the filter cake is washed with water until it becomes white to obtain a wet product 2; (4) The wet product 1 and the wet product 2 obtained in step (3) are mixed and dried to obtain 6-amino-meta-cresol.

2. The production process of 6-amino-meta-cresol according to claim 1, wherein In step (1), the mass ratio of 6-nitro-meta-cresol, hydrazine hydrate, the portion of palladium-carbon and the remaining palladium-carbon is 120:110:(2-2.5):0.

5.

3. The production process of 6-amino-meta-cresol according to claim 1, wherein In step (1), 6-nitro-meta-cresol and palladium-carbon are placed in a reaction kettle, stirred, and heated to 80° C. and refluxed. The hydrazine hydrate is added dropwise for 5 hours. The temperature is controlled to 70° C. and refluxed during the addition of hydrazine hydrate. After the addition of hydrazine hydrate is completed, the mixture is kept warm at 70° C. for 1 hour, and the remaining palladium-carbon is added and the reaction is continued until the 6-nitro-meta-cresol is completely reacted.

4. The production process of 6-amino-meta-cresol according to claim 1, wherein In step (2), the filtrate obtained by hot filtration is added to a reactor and cooled to 5°C.

5. The production process of 6-amino-meta-cresol according to claim 1, wherein In step (3), the temperature of the distillation residue is cooled to 5°C.

6. The production process of 6-amino-meta-cresol according to claim 1, wherein In step (4), the drying temperature is 70-80° C. and the drying time is 8 hours.

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