CN115838334A - A kind of preparation method of 2,5-diaminotoluene sulfate - Google Patents

Abstract

The invention relates to the field of fine chemical materials, in particular to a novel mild, efficient and economical preparation technology of 2, 5-diaminotoluene sulfate, and the technology can realize one-pot boiling. The synthesis route of the invention takes cheap o-toluidine as a raw material, other materials are cheap and easy to obtain, and the production method of obtaining 2, 5-diaminotoluene sulfate by adopting 500-mesh zinc powder through a one-pot boiling method is determined by exploring the influence of different mesh zinc powder on the reaction result. The reaction safety, operability and yield are better than those of the existing method, the target product is simple and convenient to separate, and compared with the prior art, the synthetic route has higher market competitiveness.

Description

A kind of preparation method of 2,5-diaminotoluene sulfate

technical field

The invention relates to the field of fine chemical materials, in particular to a new process technology for the mild, efficient and economical preparation of 2,5-diaminotoluene sulfate.

Background technique

2,5-diaminotoluene sulfate is an important organic intermediate and chemical product. It has important uses in the fields of hair dye, medicine, polymer materials and national defense industry. In addition, it can also be used as an auxiliary agent in Membrane treatment. Such as 2,5-diaminotoluene sulfate.

Since the 2,5-TDA structure contains two amino groups in the para position, it is easy to oxidize and can be used in hair dyes. The two amino groups in the para position naturally become the preferred monomers for linear polyamides, imides and other polymers. From the appearance of 2,5-TDA substance at the beginning of the last century to the 1980s, due to the limitation of the discovery of the application field, its demand was small and there were not many synthesis and application reports. Since the 1990s, with the rise of beauty salons around the world, it has been found that 2,5-diaminotoluene is more effective than p-phenylenediamine and safer for human health as an effective hair color component in hair dyes. At the beginning, considering the need for good stability of 2,5-TDA products, various protection methods were studied to make 2,5-TDA achieve a more ideal anti-oxidation effect. After that, the series of 2,5-diaminotoluene Products (2,5-TDAs) began to appear one after another, and were valued and developed by researchers and applications.

2,5-TDAs mainly include: 2,5-diaminotoluene (2,5-TDA) and its aqueous solution, 2,5-diaminotoluene sulfate (2,5-TDAS) and 2,5-diaminotoluene Hydrochloride (2,5-TDAH) and other varieties have a wide range of applications:

The first is 2,5-diaminotoluene sulfate 2,5-TDAS, which has been widely used as a precursor of high-grade hair dye hair color components, that is, coupling components, including black, purple, purple-brown, brown-orange Other brands of hair dye cream. It is the main ingredient used in the popular dyeing of high-end hair cosmetics. Among them, the hair dyes of various brands produced by world-renowned cosmetic companies: Wella, Henkel, Goldwell in Germany, P&G in the United States, Chimex in France, and Kao in Japan all use 2, 5-TDAS is the main component, and the demand exceeds 600 tons per year. Following this, the domestic use of 2,5-TDAS in hair dyes is gradually increasing, and the market prospect is optimistic.

The second is 2,5-diaminotoluene 2,5-TDA. In addition to being used as a coupling component of hair dye, it can also be used as an intermediate to further prepare higher-grade cosmetic ingredients and pigments, and can also be used in medicine The synthesis of intermediates and drugs, as well as the synthesis of organic synthesis raw materials, polyimides and other new polymer monomers and materials; and 2,5-diaminotoluene aqueous solution 2,5-TDAaq, in addition to being conveniently used in hair dyes In addition, it can also be used as an auxiliary agent for high-performance polyamide reverse osmosis composite membrane materials to improve the water treatment capacity and salt removal rate of the membrane.

Regarding the research on the synthesis of 2,5-TDAS products, although the laboratory has successfully developed a variety of synthetic routes, due to various reasons, there are very few routes that are actually used for industrial preparation. The production route of the reduction of 2-methyl-4-nitroaniline (trade name: red base RL).

The synthesis of the red base RL has the classic method and its improved process of using B.I.O.S: its classic method is to use p-toluenesulfonyl chloride as the condensation, nitration, hydrolysis and neutralization process route of the amino protecting agent (yield 95%, using Eleven kinds of raw and auxiliary materials); the improved process is to use formic acid as an amino protecting agent to replace p-toluenesulfonyl chloride, and also perform condensation, nitration, hydrolysis, and separation (yield 70%, the raw and auxiliary materials used are six kind).

The reduction of red base RL, the production technology that adopts at present has catalytic hydrogenation and iron powder reduction method: its catalytic hydrogenation process has few side reactions, good product quality, high yield, and carries out liquid phase hydrogenation in methanol solvent 1. Directly add sulfuric acid to precipitate salty salt, and realize clean production after solvent recovery; although the iron powder reduction process is simple and mature, with low cost and conventional equipment, it will produce a large amount of iron sludge and wastewater containing aromatic amines, how to reduce it? Amount of iron sludge and waste water.

It can be seen that the current industrial production of 2,5-TDAS through the red-based RL reduction route, regardless of the use of the classic method of B.I.O.S or the improved process to produce red-based RL, because the process must carry out amino protection, nitration, and deprotection of OT. Complex process.

Contents of the invention

The present invention provides a kind of use o-toluidine as raw material and solvent, through the method of diazo, coupling, reduction and distillation to produce 2,5-diaminotoluene sulfate, the raw material o-toluidine is easy to recover in the method, and can be repeated Utilization, the solvent required in the intermediate process can be recycled repeatedly, the waste liquid is less, and the yield increases with more recycling times.

【Detailed ways】

Further illustrate gist of the present invention below in conjunction with specific embodiment, but protection scope of the present invention is not limited thereto;

Example 1: Synthesis of crude 2,5-diaminotoluene sulfate (1)

Add 128mL of o-toluidine to the designated container, add 33mL of concentrated hydrochloric acid, cool down to 0~10°C; add 10.32g of sodium nitrite into 29mL of water, stir until completely dissolved, and prepare a sodium nitrite solution; After the cooling of the solution is completed, the sodium nitrite solution is added dropwise to the reaction system, and the dropping temperature is controlled at 0~10°C; % hydrochloric acid 20mL, heat up to 40°C and keep warm for 45~60min. After the heat preservation is over, add 23.7g of 500-mesh zinc powder into the three-necked flask, rinse the inner wall of the three-necked flask with a small amount of methanol, and rinse the remaining zinc powder on the wall to In the reaction solution, stir and heat up to 80°C, slowly add 85mL of 37% hydrochloric acid dropwise until the dropwise addition is complete, after the dropwise addition, cool the reaction solution to about 60°C; dissolve 70g of sodium hydroxide in 100mL of water, and drop to normal temperature, after the cooling of the reaction solution is completed, add the prepared alkali solution dropwise to the reaction solution until all the solids in the reaction solution are white; Zinc oxide, combine all liquids; start distillation, when the temperature of the reaction solution rises to 80°C, collect methanol, when the internal temperature rises to above 95°C, switch the distillate collection bottle, collect the water fraction, TLC confirms that there is no o-toluidine in the reaction system Finally, add 2g of activated carbon and 2g of sodium hydrosulfite into it, raise the temperature and reflux for 0.5h, filter while it is hot, and rinse with water; after the filtration is completed, extract the reaction solution with 100*5mL dichloromethane after cooling down, and combine the organic phases, Concentrate dichloromethane to 50~100mL; add 16mL concentrated sulfuric acid to 20mL water, stir and dilute, add 100mL water to the concentrated organic phase, add the prepared dilute sulfuric acid, stir until a large amount of solids are formed, and then add Add 50mL of methanol, stir and cool down to 0~5°C, separate the material for 1h, then filter with suction, rinse with methanol until the washing liquid is clear, and collect the crude wet product.

Embodiment two: o-toluidine solvent recovery

Wash the distilled aqueous phase twice with 50 mL of dichloromethane, combine the organic phases, concentrate the organic phase until no liquid drops remain, and collect orange-yellow to orange-red o-toluidine and the distilled dichloromethane respectively.

The methanol obtained by distillation contains a small amount of water and o-toluidine. During recovery and treatment, all the methanol is first concentrated and then collected, and the remaining part of the concentration is added to the distilled water phase for combined treatment.

Embodiment three: the synthesis of 2,5-diaminotoluene sulfate high-quality goods

Put the collected crude wet product into a single-necked flask, add 50mL of water, then add 10mL of ammonia water to dissolve all the solid materials, then add 2g of activated carbon, heat up and reflux for 0.5h, filter while it is hot, wash the filter residue with water, and combine the water phase , Stir and add 14mL concentrated sulfuric acid into the water phase, stir until a large amount of solids are formed, then add 50mL methanol, stir and cool down to 0~5°C, separate the material for 1h, then suction filter, rinse with methanol until the washing liquid is clear, The wet product was collected and dried at 60°C to obtain 24.7g of white powder with a yield of 75%. If recovered o-toluidine was used, 31.3g of white powder was obtained with a yield of 95%.

Example 4: Synthesis of crude 2,5-diaminotoluene sulfate (2)

Add 128mL of o-toluidine to the designated container, add 33mL of concentrated hydrochloric acid, cool down to 0~10°C; add 10.32g of sodium nitrite into 29mL of water, stir until completely dissolved, and prepare a sodium nitrite solution; After the cooling of the solution is completed, the sodium nitrite solution is added dropwise to the reaction system, and the dropping temperature is controlled at 0~10°C; % hydrochloric acid 20mL, heat up to 40°C and keep warm for 45~60min. After the heat preservation is over, add 23.7g of 100 mesh zinc powder into the three-necked flask, rinse the inner wall of the three-necked flask with a small amount of methanol, and rinse the remaining zinc powder on the wall to In the reaction solution, stir and heat up to 80°C, slowly add 85mL of 37% hydrochloric acid dropwise until the dropwise addition is complete, after the dropwise addition, cool the reaction solution to about 60°C; dissolve 70g of sodium hydroxide in 100mL of water, and drop to normal temperature, after the cooling of the reaction solution is completed, add the prepared alkali solution dropwise to the reaction solution until all the solids in the reaction solution are white; Zinc oxide, combine all liquids; start distillation, when the temperature of the reaction solution rises to 80°C, collect methanol, when the internal temperature rises to above 95°C, switch the distillate collection bottle, collect the water fraction, TLC confirms that there is no o-toluidine in the reaction system Finally, add 2g of activated carbon and 2g of sodium hydrosulfite into it, raise the temperature and reflux for 0.5h, filter while it is hot, and rinse with water; after the filtration is completed, extract the reaction solution with 100*5mL dichloromethane after cooling down, and combine the organic phases, Concentrate dichloromethane to 50~100mL; add 16mL concentrated sulfuric acid to 20mL water, stir and dilute, add 100mL water to the concentrated organic phase, add the prepared dilute sulfuric acid, stir until a large amount of solids are formed, and then add Add 50mL of methanol, stir and cool down to 0~5°C, separate the material for 1h, then filter with suction, rinse with methanol until the washing liquid is clear, and collect the crude wet product.

Embodiment five: o-toluidine solvent recovery (2)

Wash the distilled aqueous phase twice with 50 mL of dichloromethane, combine the organic phases, concentrate the organic phase until no liquid drops remain, and collect orange-yellow to orange-red o-toluidine and the distilled dichloromethane respectively.

The methanol obtained by distillation contains a small amount of water and o-toluidine. During recovery and treatment, all the methanol is first concentrated and then collected, and the remaining part of the concentration is added to the distilled water phase for combined treatment.

Example 6: Synthesis of 2,5-diaminotoluene sulfate fine product (3)

Put the collected crude wet product into a single-necked flask, add 50mL of water, then add 10mL of ammonia water to dissolve all the solid materials, then add 2g of activated carbon, heat up and reflux for 0.5h, filter while it is hot, wash the filter residue with water, and combine the water phase , Stir and add 14mL concentrated sulfuric acid into the water phase, stir until a large amount of solids are formed, then add 50mL methanol, stir and cool down to 0~5°C, separate the material for 1h, then suction filter, rinse with methanol until the washing liquid is clear, The wet product was collected and dried at 60°C to obtain 20.7g of white powder with a yield of 62.8%. If recovered o-toluidine was used, 25.3g of white powder was obtained with a yield of 76.8%.

Example 7: Synthesis of crude 2,5-diaminotoluene sulfate (3)

Add 128mL of o-toluidine to the designated container, add 33mL of concentrated hydrochloric acid, cool down to 0~10°C; add 10.32g of sodium nitrite into 29mL of water, stir until completely dissolved, and prepare a sodium nitrite solution; After the cooling of the solution is completed, the sodium nitrite solution is added dropwise to the reaction system, and the dropping temperature is controlled at 0~10°C; % hydrochloric acid 20mL, heat up to 40°C and keep warm for 45~60min. After the heat preservation is over, add 23.7g of 200-mesh zinc powder into the three-necked flask, rinse the inner wall of the three-necked flask with a small amount of methanol, and rinse the remaining zinc powder on the wall to In the reaction solution, stir and heat up to 80°C, slowly add 85mL of 37% hydrochloric acid dropwise until the dropwise addition is complete, after the dropwise addition, cool the reaction solution to about 60°C; dissolve 70g of sodium hydroxide in 100mL of water, and drop to normal temperature, after the cooling of the reaction solution is completed, add the prepared alkali solution dropwise to the reaction solution until all the solids in the reaction solution are white; Zinc oxide, combine all liquids; start distillation, when the temperature of the reaction solution rises to 80°C, collect methanol, when the internal temperature rises to above 95°C, switch the distillate collection bottle, collect the water fraction, TLC confirms that there is no o-toluidine in the reaction system Finally, add 2g of activated carbon and 2g of sodium hydrosulfite into it, raise the temperature and reflux for 0.5h, filter while it is hot, and rinse with water; after the filtration is completed, extract the reaction solution with 100*5mL dichloromethane after cooling down, and combine the organic phases, Concentrate dichloromethane to 50~100mL; add 16mL concentrated sulfuric acid to 20mL water, stir and dilute, add 100mL water to the concentrated organic phase, add the prepared dilute sulfuric acid, stir until a large amount of solids are formed, and then add Add 50mL of methanol, stir and cool down to 0~5°C, separate the material for 1h, then filter with suction, rinse with methanol until the washing liquid is clear, and collect the crude wet product. After salt formation, 22.7g of finished product was obtained, with a yield of 68.9%. If recovered o-toluidine was used, 27.3g of white powder was obtained, with a yield of 82.9%.

Example 8: Synthesis of crude 2,5-diaminotoluene sulfate (4)

Add 128mL of o-toluidine to the designated container, add 33mL of concentrated hydrochloric acid, cool down to 0~10°C; add 10.32g of sodium nitrite into 29mL of water, stir until completely dissolved, and prepare a sodium nitrite solution; After the cooling of the solution is completed, the sodium nitrite solution is added dropwise to the reaction system, and the dropping temperature is controlled at 0~10°C; % hydrochloric acid 20mL, heat up to 40°C and keep warm for 45~60min. After the heat preservation is over, add 23.7g of 800-mesh zinc powder into the three-necked flask, rinse the inner wall of the three-necked flask with a small amount of methanol, and rinse the remaining zinc powder on the wall to In the reaction solution, stir and heat up to 80°C, slowly add 85mL of 37% hydrochloric acid dropwise until the dropwise addition is complete, after the dropwise addition, cool the reaction solution to about 60°C; dissolve 70g of sodium hydroxide in 100mL of water, and drop to normal temperature, after the cooling of the reaction solution is completed, add the prepared alkali solution dropwise to the reaction solution until all the solids in the reaction solution are white; Zinc oxide, combine all liquids; start distillation, when the temperature of the reaction solution rises to 80°C, collect methanol, when the internal temperature rises to above 95°C, switch the distillate collection bottle, collect the water fraction, TLC confirms that there is no o-toluidine in the reaction system Finally, add 2g of activated carbon and 2g of sodium hydrosulfite into it, raise the temperature and reflux for 0.5h, filter while it is hot, and rinse with water; after the filtration is completed, extract the reaction solution with 100*5mL dichloromethane after cooling down, and combine the organic phases, Concentrate dichloromethane to 50~100mL; add 16mL concentrated sulfuric acid to 20mL water, stir and dilute, add 100mL water to the concentrated organic phase, add the prepared dilute sulfuric acid, stir until a large amount of solids are formed, and then add Add 50mL of methanol, stir and cool down to 0~5°C, separate the material for 1h, then filter with suction, rinse with methanol until the washing liquid is clear, and collect the crude wet product. After salt formation, 23.7g of finished product was obtained, with a yield of 71.95%. If recovered o-toluidine was used, 30.3g of white powder was obtained, with a yield of 92%.

Example 9: Synthesis of crude 2,5-diaminotoluene sulfate (5)

Add 128mL of o-toluidine to the designated container, add 33mL of concentrated hydrochloric acid, cool down to 0~10°C; add 10.32g of sodium nitrite into 29mL of water, stir until completely dissolved, and prepare a sodium nitrite solution; After the cooling of the solution is completed, the sodium nitrite solution is added dropwise to the reaction system, and the dropping temperature is controlled at 0~10°C; % hydrochloric acid 20mL, heat up to 40°C and keep warm for 45~60min. After the heat preservation is over, add 23.7g of 1000 mesh zinc powder into the three-necked flask, rinse the inner wall of the three-necked flask with a small amount of methanol, and rinse the remaining zinc powder on the wall to In the reaction solution, stir and heat up to 80°C, slowly add 85mL of 37% hydrochloric acid dropwise until the dropwise addition is complete, after the dropwise addition, cool the reaction solution to about 60°C; dissolve 70g of sodium hydroxide in 100mL of water, and drop to normal temperature, after the cooling of the reaction solution is completed, add the prepared alkali solution dropwise to the reaction solution until all the solids in the reaction solution are white; Zinc oxide, combine all liquids; start distillation, when the temperature of the reaction solution rises to 80°C, collect methanol, when the internal temperature rises to above 95°C, switch the distillate collection bottle, collect the water fraction, TLC confirms that there is no o-toluidine in the reaction system Finally, add 2g of activated carbon and 2g of sodium hydrosulfite into it, raise the temperature and reflux for 0.5h, filter while it is hot, and rinse with water; after the filtration is completed, extract the reaction solution with 100*5mL dichloromethane after cooling down, and combine the organic phases, Concentrate dichloromethane to 50~100mL; add 16mL concentrated sulfuric acid to 20mL water, stir and dilute, add 100mL water to the concentrated organic phase, add the prepared dilute sulfuric acid, stir until a large amount of solids are formed, and then add Add 50mL of methanol, stir and cool down to 0~5°C, separate the material for 1h, then filter with suction, rinse with methanol until the washing liquid is clear, and collect the crude wet product. After salt formation, 23.2g of finished product was obtained, with a yield of 70.4%. If recovered o-toluidine was used, 29.1g of white powder was obtained, with a yield of 88.3%.

Through the implementation case, it can be found that 500-mesh zinc powder has the best effect on the experiment and can obtain the highest yield, and the use of recycled o-toluidine can recycle the residual product in o-toluidine and obtain a higher yield.

It should be emphasized that the above-mentioned embodiments are only illustrative rather than restrictive. Based on the disclosure of this application, any adjustment or change of reaction conditions or parameters that may be commonly used by a skilled person will not deviate from the gist of the present invention. The scope of protection of this patent shall be subject to the items recorded in the relevant rights.

Claims (12)

1. A process for the preparation of 2, 5-diaminotoluene sulfate, comprising the following steps and shown in the chemical reaction formula:

(1) Under certain conditions, o-toluidine, acid and sodium nitrite are subjected to diazotization reaction to prepare 2-amino azotoluene and diazonium salt;

(2) Under certain conditions, the diazonium salt is converted into 2-amino azotoluene through reaction;

(3) Under the acidic condition, 2-amino azotoluene is reduced by zinc powder to obtain o-toluidine and 2, 5-diaminotoluene;

(4) Salifying 2, 5-diaminotoluene and sulfuric acid, purifying and drying to obtain 2, 5-diaminotoluene sulfate;

。

2. the process according to claim 1, wherein the low temperature in step (1) is-25 to 35 degrees, preferably-10 to 20 degrees, more preferably 0 to 10 degrees.

3. The process according to claim 1, wherein the acid in step (1) is selected from hydrochloric acid, glacial acetic acid, sulfuric acid, etc.; hydrochloric acid is commonly used as a proton source; the ratio of the o-toluidine to the sodium nitrite to the acid is 0.80 to 1.60:0.15:0.39, preferably 1.15 to 1.25:0.15:0.39.

4. the process according to claim 1, wherein the o-toluidine in step (1) is either o-toluidine recovered from the process or fresh o-phenylenediamine.

5. The process according to claim 1, wherein said sodium nitrite solution in step (1) has a concentration of 20-50%, preferably 25-45%, more preferably 30-40%.

6. The process according to claim 1, wherein the dropping temperature of the sodium nitrite solution in step (1) is-10 to 20 degrees, preferably-5 to 15 degrees, and more preferably 0 to 10 degrees.

7. The process according to claim 1, wherein the holding time in step (1) is 0.5 to 5 hours, preferably 0.8 to 3 hours, more preferably 1 to 2 hours.

8. The process of claim 1, wherein the acid in step (2) is selected from hydrochloric acid, glacial acetic acid, sulfuric acid, etc., hydrochloric acid is usually used as a proton source, and the added hydrochloric acid is 10 to 25 mol%, preferably 15 to 20 mol%, based on the raw materials; the heat preservation temperature is 30-50 ℃, and preferably 35-45 ℃; the heat preservation time is 0.5 to 1.5 hours, and preferably 0.75 to 1h.

9. The process as claimed in claim 1, wherein said acid in step (3) is hydrochloric acid, and said acid is added in an amount of 70% by mole based on the starting material, and said zinc powder may be 50 mesh, 100 mesh, 200 mesh, 325 mesh, 500 mesh, 800 mesh and 1000 mesh, preferably 100 mesh to 800 mesh zinc powder, more preferably 200 mesh to 500 mesh.

10. The process method as claimed in claim 1, wherein the alkali solution in step (3) can be sodium hydroxide solution or potassium hydroxide solution, the added alkali is 150% by mol of the raw materials, and the concentration of the alkali solution is 50-75%; the organic solvent may be dichloromethane or dichloroethane; the mole percentage of the sodium hydrosulfite and the active carbon used for extraction as raw materials is 1.0-3.0%.

11. The process of claim 1, wherein the extraction in step (4) is carried out using 12.5 mol% sulfuric acid as raw material, diluted to about 50 mol%; the final yield is 60% -90%, and if the recovered o-toluidine is used in the step (1), the yield can reach 90% -120%.

12. The process as claimed in claim 1, wherein the process is as follows:

(1) Adding acid into o-toluidine as a solvent, and cooling to a low temperature; adding sodium nitrite into water, stirring until the sodium nitrite is completely dissolved, and preparing sodium nitrite solution; after the o-toluidine solution is cooled, dropwise adding the sodium nitrite solution into the reaction system at a controlled temperature, and after dropwise adding is finished, controlling the temperature to keep the temperature;

(2) After the heat preservation is finished, acid is added dropwise, and the heat preservation is continued for a period of time after the temperature is raised;

(3) After the heat preservation is finished, adding zinc powder into the reaction system, stirring and heating to 80 ℃, slowly dropwise adding hydrochloric acid, and after the dropwise adding is finished, cooling the reaction solution to about 60 ℃; dissolving alkali in water, cooling to normal temperature, and after the reaction solution is cooled, dropwise adding prepared alkali liquor into the reaction solution until all solids in the reaction solution are white; after the dropwise addition is finished, the system is filtered, the solid zinc hydroxide is washed by methanol, and all the liquid is combined; starting distillation and collecting water fraction; after confirming that no o-toluidine exists in the reaction system, adding activated carbon and sodium hydrosulfite into the reaction system, heating and refluxing, filtering while hot, and leaching with clear water; after filtering, cooling, extracting the reaction liquid by using an organic solvent, merging organic phases, and concentrating;

(4) Adding concentrated sulfuric acid into water, stirring and diluting, adding water into the concentrated organic phase, adding prepared dilute sulfuric acid, stirring until a large amount of solid is generated, adding methanol, stirring and cooling to 0-5 ℃, separating for 1h, then carrying out suction filtration, eluting with methanol until the washing liquid is clear, collecting a crude wet product, adding the crude wet product into a single-neck flask, adding water, adding ammonia water to completely dissolve the solid material, adding activated carbon, heating and refluxing for 0.5h, filtering while hot, washing filter residues with clear water, combining the water phases, stirring and adding concentrated sulfuric acid into the water phase, stirring until a large amount of solid is generated, adding methanol, stirring and cooling to 0-5 ℃, separating for 1h, then carrying out suction filtration, eluting with methanol until the washing liquid is clear, collecting a wet product, and drying at 60 ℃ to obtain white powder.