1, 4-diamino-2, 3-dicyanoanthraquinone and preparation method thereof

Abstract

The invention provides 1, 4-diamino-2, 3-dicyano anthraquinone and a preparation method of the 1, 4-diamino-2, 3-dicyano anthraquinone. The preparation method comprises the following steps: 1, mixing 1, 4-diamino-2-sulfonic anthraquinone with a solvent, and adjusting the pH value to 7-9.5 to obtain a mixed product; 2, an oxidizing agent, sodium cyanide and an alkali binding agent are added into the mixed product for a cyanidation reaction, and a cyanidation product containing 1, 4-diamino-2, 3-dicyanoanthraquinone is obtained. The preparation method disclosed by the invention has the characteristics of low environmental toxicity, low environmental protection pressure, simple process operation and low energy consumption. The preparation method of the 1, 4-diamino-2, 3-dicyanoanthraquinone is clear in technological process, simple and convenient to operate, short in production period, mild in reaction condition and high in product purity, meanwhile, cyclic utilization of resources is achieved, the production cost is reduced, and the production efficiency is improved.

Description

Technical Field

[0001] The invention relates to 1,4-diamino-2,3-dicyanoanthraquinone and a preparation method thereof, and belongs to the field of dye intermediate synthesis. Background Art

[0002] 1,4-Diamino-2,3-dicyanoanthraquinone is an important dye intermediate with special uses in the printing and dyeing industry. It is an intermediate for synthesizing many dyes and pigments with excellent performance. It is currently mainly used in the production of disperse blue 60. The traditional synthesis method is to use 1,4-diaminoanthraquinone leuco as raw material, obtain 1,4-diamino-2,3-dichloroanthraquinone through chlorination, and then sulfonate to obtain 1,4-diamino-2,3-disulfonic acid anthraquinone, and finally replace it with sodium cyanide to obtain 1,4-diamino-2,3-dicyanoanthraquinone. However, this method must go through two steps, the process is long, the total yield is low, and the product quality is poor. In addition, the mother liquor cannot be directly applied, resulting in a large amount of wastewater, and the sewage treatment is relatively difficult.

[0003] CN1995012A discloses a method of using o-dichlorobenzene as solvent, heating under negative pressure to remove trace water in the system, and then oxidizing and sulfonating 1,4-diaminoanthraquinone leuco body with chlorosulfonic acid, neutralizing the obtained material, distilling o-dichlorobenzene, filtering to remove impurities, and acidifying, and then draining and washing the precipitated material, and obtaining the wet product filter cake 1,4-diaminoanthraquinone-2-sulfonic acid anthraquinone, and using a mixture of N,N-dimethylformamide and water as solvent in the presence of an oxidant and a alkali agent, and cyaniding with sodium cyanide to obtain 1,4-diamino-2,3-dicyanoanthraquinone. However, the patent method has its own defects. The production cost of the method is too high, and the solvent N,N-dimethylformamide is not studied for recycling and reuse. It is simply proposed that N,N-dimethylformamide is recycled and reused.

[0004] In addition, the sodium cyanide used in the method described in CN1995012A is excessive, and the method does not truly achieve the recycling of sodium cyanide. If the excessive use of sodium cyanide is not recycled, the sewage will inevitably contain a large amount of sodium cyanide, polluting the environment. Therefore, this method does not really reduce the production cost of 1,4-diamino-2,3-cyanoanthraquinone. For this traditional process method, there are the following defects: 1. The operation is cumbersome, energy-consuming, and the cost of recycling is high, and the production cost of the product is high; 2. The water content of the recovered dimethylformamide is still relatively high; 3. Excessive sodium cyanide is difficult to handle and wastes resources; 4. Part of the product dissolved in the solution cannot be recovered; 5. The overall amount of solvent used is relatively large.

[0005] CN 1163262A uses leuco form of 1,4-diaminoanthraquinone as raw material, uses sulfuryl chloride to carry out chlorination in an o-dichlorobenzene medium, blows away excess sulfuryl chloride after chlorination, then adds sulfuric acid, boric acid and a catalyst to carry out esterification, and removes water produced by esterification by distillation. Although the raw materials used in this method are cheap, carrying out chlorination and esterification in the same reaction medium can also reduce production costs. However, the method still has the following shortcomings: ① The preparation of 1,4-diaminoanthraquinone-2,3-disulfonic acid requires three steps of chlorination, esterification and sulfonation, and the process route is still relatively long. Therefore, its total yield is still not ideal, only 87-90%, and the product purity is relatively low, only 93.5-94.0%, which still cannot meet the requirements for producing excellent dyes and pigments; ② During esterification, sulfuric acid and boric acid are used, and the corrosion of equipment has not been solved; ③ Each step of the operation is relatively complicated. For example, after chlorination, it is necessary to blow away the excess sulfuryl chloride and the generated hydrogen chloride and sulfur dioxide before esterification can be carried out; during sulfonation, the solvent must be recovered by blowing and distilling while reacting, so the operation is still inconvenient and difficult to control.

[0006] CN102993049A discloses a method of using 1,4-diamino-2-sulfonic anthraquinone as a raw material, a mixture of N,N-dimethylformamide and water as a solvent, nitrobenzene as an oxidant, acetic acid as an alkali agent, cyaniding with sodium cyanide in a reaction device, filtering, washing, and drying to obtain 1,4-diamino-2,3-dicyanoanthraquinone. Although the reaction conditions have infinitely tended to the requirements of the preparation scheme target, due to the characteristics of N,N-dimethylformamide as a solvent itself and the limitation of the number of times the mother liquor can be used, there are still some shortcomings.

[0007] Wastewater containing N,N-dimethylacetamide has certain toxicity and high stability. If it is discharged into the external environment at will, it will not only cause serious economic losses, but also cause serious harm to the environment. This feature causes the mother liquor to fail to meet the sewage discharge requirements and cannot be discharged directly. In addition, the wastewater containing N,N-dimethylacetamide contains different components, and the treatment processes cannot be mutually borrowed. Therefore, how to recycle N,N-dimethylacetamide is the main technical problem that the process products need to deal with urgently.

[0008] Therefore, it has become a technical problem to be solved urgently to study a preparation method of 1,4-diamino-2,3-dicyanoanthraquinone with low environmental toxicity, low environmental pressure, simple process operation and low energy consumption, which can also treat wastewater containing organic solvents. Summary of the invention

[0009] Problem that the invention aims to solve

[0010] In view of the technical problems existing in the prior art, the present invention first provides a method for preparing 1,4-diamino-2,3-dicyanoanthraquinone, which has the characteristics of low environmental toxicity, low environmental pressure, simple process operation and low energy consumption. The method for preparing 1,4-diamino-2,3-dicyanoanthraquinone of the present invention has a clear process flow, simple operation and shortened production cycle.

[0011] Furthermore, the present invention also provides 1,4-diamino-2,3-dicyanoanthraquinone prepared by the preparation method of the present invention; and the yield and purity of 1,4-diamino-2,3-dicyanoanthraquinone are high.

[0012] Solutions for solving problems

[0013] The present invention provides a method for preparing 1,4-diamino-2,3-dicyanoanthraquinone, which comprises the following steps:

[0014] Step 1: After mixing 1,4-diamino-2-sulfonic acid anthraquinone with a solvent, the pH value is adjusted to 7-9.5 to obtain a mixed product;

[0015] Step 2: adding an oxidant, sodium cyanide and an alkali agent to the mixed product to carry out a cyanation reaction to obtain a cyanation product containing 1,4-diamino-2,3-dicyanoanthraquinone.

[0016] According to the preparation method of the present invention, wherein in step 1, the solvent comprises a recovery solution; wherein the recovery solution comprises a solution obtained by distilling process wastewater containing an organic solvent, and the organic solvent comprises one or a combination of two or more of N,N-dimethylformamide, N,N-dimethylacetamide and dimethyl sulfoxide;

[0017] Preferably, in the recovery solution, the mass concentration of the organic solvent is 65-98%;

[0018] Optionally, the solvent further comprises an inorganic solvent; based on the total mass of the solvent, the content of the recovered solution is 70 to 99%;

[0019] Further preferably, the distillation conditions include: adjusting the vacuum degree of the distillation kettle to -0.1 to -0.05 MPa and then raising the temperature to 70 to 150° C., and the steam pressure in the distillation kettle is 0.1 to 0.5 MPa;

[0020] When the distillation is finished, the temperature in the still is 100-180°C, the vacuum degree is -0.1 to -0.05 MPa, and the steam pressure is 0.3 to 0.8 MPa.

[0021] According to the preparation method of the present invention, before the distillation, a rectification step is also included;

[0022] Preferably, the distillation comprises the step of collecting and removing the front fraction using a connected distillation tower and a distillation kettle to obtain a crude distillation product;

[0023] More preferably, the distillation comprises: controlling the vacuum degree at the top of the distillation tower to -0.1 to -0.05 MPa for full reflux, preferably, the full reflux time is 5 to 20 min, the temperature in the distillation kettle is 70-80°C, the jacket steam pressure of the distillation kettle is 0.1 to 0.5 MPa, and the top temperature of the distillation tower is 60 to 70°C; then controlling the reflux ratio to 1:0.1 to 1.5 for distillation and removing the front fraction; when the difference between the temperature in the distillation kettle and the top temperature of the distillation tower is 25 to 35°C, the distillation is terminated to obtain a crude distillation product.

[0024] According to the preparation method of the present invention, in the step 1, the pH value is adjusted to 7-9.5 using an ammonia solution, and preferably, the mass fraction of the ammonia solution is 5-25%.

[0025] According to the preparation method of the present invention, the step 2 comprises the following steps:

[0026] The oxidant is added to the mixed product, and the temperature of the reaction system is adjusted to 40-50° C.; then, the mixed product is mixed with the sodium cyanide, and the temperature of the reaction system is adjusted to 70-75° C. for cyanidation reaction; and the alkali agent is added to the reaction system to adjust the pH value to obtain a cyanidation product containing 1,4-diamino-2,3-dicyanoanthraquinone.

[0027] According to the preparation method of the present invention, during the cyanation reaction, the pH value of the reaction system is 8 to 10.5, and the cyanation reaction is completed when the content of sulfonic acid in the reaction system is less than 2%;

[0028] Preferably, the cyanation reaction time is 8 to 15 hours.

[0029] According to the preparation method of the present invention, the mass ratio of the sodium cyanide to the 1,4-diamino-2-sulfonic acid anthraquinone is 0.3 to 1:1;

[0030] The mass ratio of the oxidant to the 1,4-diamino-2-sulfonic acid anthraquinone is 0.05 to 0.3:1;

[0031] The sodium cyanide is added in the form of solid sodium cyanide or sodium cyanide solution. Preferably, the mass fraction of sodium cyanide in the sodium cyanide solution is 15-90%.

[0032] According to the preparation method of the present invention, the oxidant comprises one or a combination of two or more of nitrobenzene, sodium m-nitrobenzene sulfonate, and sodium p-nitrobenzene sulfonate;

[0033] The alkali agent includes one or a combination of two or more of sulfuric acid, hydrochloric acid and acetic acid;

[0034] Preferably, the alkali-binding agent comprises a sulfuric acid solution with a concentration of 20-40%.

[0035] According to the preparation method of the present invention, the preparation method further comprises step 3, wherein step 3 comprises the step of washing the cyanide product with hot water at 50 to 95° C. to remove inorganic salts.

[0036] The present invention also provides 1,4-diamino-2,3-dicyanoanthraquinone, which is prepared by the preparation method of the present invention, wherein the purity of the 1,4-diamino-2,3-dicyanoanthraquinone is above 95%, and the yield of the 1,4-diamino-2,3-dicyanoanthraquinone is above 90%.

[0037] Effects of the Invention

[0038] The preparation method of the present invention has the characteristics of low environmental toxicity, low environmental pressure, simple process operation and low energy consumption. The preparation method of 1,4-diamino-2,3-dicyanoanthraquinone of the present invention has a clear process flow, simple operation, shortened production cycle, mild reaction conditions, high product purity, and realizes the recycling of resources, reduces production costs, and improves production efficiency.

[0039] The 1,4-diamino-2,3-dicyanoanthraquinone prepared by the preparation method of the invention has high yield and high purity. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 A process flow diagram showing one embodiment of the present invention is shown. DETAILED DESCRIPTION

[0041] Various exemplary embodiments, features and aspects of the present invention will be described in detail below. The word "exemplary" used here means "used as an example, embodiment or illustrative". Any embodiment described here as "exemplary" is not necessarily interpreted as being superior or better than other embodiments.

[0042] In addition, in order to better illustrate the present invention, numerous specific details are provided in the following specific embodiments. It should be understood by those skilled in the art that the present invention can be implemented without certain specific details. In other examples, methods, means, equipment and steps well known to those skilled in the art are not described in detail in order to highlight the subject matter of the present invention.

[0043] Unless otherwise stated, the units used in this specification are all international standard units, and the numerical values ​​and numerical ranges appearing in the present invention should be understood to include the inevitable systematic errors in industrial production.

[0044] In this specification, the word "may" means both performing a certain process and not performing a certain process.

[0045] In this specification, the references to "some specific / preferred embodiments", "other specific / preferred embodiments", "embodiments", etc., mean that the specific elements (e.g., features, structures, properties and / or characteristics) described in connection with the embodiments are included in at least one embodiment described herein, and may or may not exist in other embodiments. In addition, it should be understood that the elements may be combined in various embodiments in any suitable manner.

[0046] In this specification, the numerical range expressed using "a numerical value A to a numerical value B" means a range including the endpoints numerical values ​​A and B.

[0047] The present invention first provides a preparation method of 1,4-diamino-2,3-dicyanoanthraquinone. The preparation method of the present invention has a short process flow, and the industrial wastewater generated can be purified to a recovery solution of a certain purity by distillation or a combination of distillation and rectification, and then recycled for multiple times. The prepared product has good quality, high yield, simple operation, greatly reduced production cost, and is environmentally friendly.

[0048] In the present invention, the main chemical reactions involved are:

[0049]

[0050] The present invention provides a method for preparing 1,4-diamino-2,3-dicyanoanthraquinone, which comprises the following steps:

[0051] Step 1: After mixing 1,4-diamino-2-sulfonic acid anthraquinone with a solvent, the pH value is adjusted to 7-9.5 to obtain a mixed product;

[0052] Step 2: adding an oxidant, sodium cyanide and an alkali agent to the mixed product to carry out a cyanation reaction to obtain a cyanation product containing 1,4-diamino-2,3-dicyanoanthraquinone.

[0053] In the present invention, the sodium cyanide is added in the form of solid sodium cyanide or sodium cyanide solution, and preferably, the mass fraction of sodium cyanide in the sodium cyanide solution is 15-90%. When the solid sodium cyanide or sodium cyanide solution is used for the cyanidation reaction, not only the purity of the product 1,4-diamino-2,3-cyanoanthraquinone is greatly improved to more than 95.0%, but the average yield can also reach more than 90.0%.

[0054] The preparation method of the present invention has the characteristics of low environmental toxicity, low environmental pressure, simple process operation and low energy consumption. The preparation method of 1,4-diamino-2,3-dicyanoanthraquinone of the present invention has a clear process flow, simple operation, shortened production cycle, mild reaction conditions, high product purity, and realizes the recycling of resources, reduces production costs, and improves production efficiency.

[0055] The method of the present invention has low energy consumption, is simple and easy to operate, and has low product production cost; part of the product dissolved in the solvent can be recycled, thereby reducing the loss of the product in the solvent; the total solvent usage is only 10-15% of the traditional method, which greatly reduces the solvent consumption.

[0056] In some specific embodiments, the solvent includes a recovery solution. In the present invention, the recovery solution can be obtained by distilling process wastewater containing an organic solvent, or rectifying and then distilling, wherein the organic solvent includes one or a combination of two or more of N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DMAc) and dimethyl sulfoxide (DMSo). The inorganic solvent is water.

[0057] Preferably, the mass concentration of the organic solvent in the recovery solution can be 65-98%. By using a recovery solution with a purity of 65-98%, the wastewater generated in the preparation process of Disperse Blue 165, Disperse Blue 165:1, Disperse Blue 366 and 1,4-diamino-2,3-dicyanoanthraquinone can be effectively recovered and the relevant wastewater can be effectively utilized.

[0058] In some specific embodiments, the solvent further comprises an inorganic solvent; based on the total mass of the solvent, the content of the recovered solution is 70-99%. In the present invention, the inorganic solvent may be water.

[0059] Specifically, a recovery solution having a mass concentration of 65 to 98% of the organic solvent can be obtained by distillation. The inventors of the present invention have found that a recovery solution having a certain concentration can be obtained by using a distillation method.

[0060] Further preferably, the distillation conditions include: adjusting the vacuum degree of the distillation kettle to -0.1 to -0.05 MPa, for example: -0.09 to -0.06 MPa, -0.08 to -0.07 MPa, and then heating to 70 to 150°C, for example: 80 to 140°C, 90 to 130°C, 100 to 120°C, etc., and the steam pressure in the distillation kettle is 0.1 to 0.5 MPa, for example: 0.2 to 0.4 MPa, etc. At the end of distillation, the temperature in the still is 100-180°C, for example, 110-170°C, 120-160°C, 130-140°C, etc., the vacuum is -0.1-0.05MPa, for example, -0.09-0.06MPa, -0.08-0.07MPa, and the steam pressure is 0.3-0.8Mpa, for example, 0.4-0.7Mpa, 0.5-0.6Mpa, etc. Distillation is carried out under the above conditions to obtain the desired recovery solution. Furthermore, in order to make the recovery efficiency of the organic solvent in the recovery solution high, the energy consumption is low, the yield is high, and the solid waste is small, especially when the organic solvent content in the recovery solution is not high, the present invention preferably performs a rectification step before distillation.

[0061] In fact, when using wastewater of dyes such as Disperse Blue 165, Disperse Blue 165:1, and Disperse Blue 366 to obtain a recovery solution, due to the high content of organic solvents in the wastewater, only distillation can be used to achieve the desired effect. When using wastewater of 1,4-diamino-2,3-dicyanoanthraquinone to obtain a recovery solution, due to the low content of organic solvents in the wastewater, a method of first distillation and then distillation can be used. By using the method of first distillation and then distillation, a recovery solution with a higher mass concentration of organic solvents can be obtained.

[0062] Preferably, the distillation comprises the step of collecting and removing the front fraction using a connected distillation tower and a distillation kettle to obtain a crude distillation product;

[0063] More preferably, the distillation comprises: controlling the top vacuum of the distillation tower to -0.1 to -0.05 MPa, for example: -0.09 to -0.06 MPa, -0.08 to -0.07 MPa, etc. for full reflux, preferably, the full reflux time is 5 to 20 min, for example: 7 to 18 min, 9 to 16 min, 11 to 14 min, 12 to 13 min, etc.; the temperature in the distillation kettle is 70-80 ° C, for example: 72 to 78 ° C, 74 to 76 ° C, etc., the distillation kettle The jacket steam pressure is 0.1-0.5MPa, for example, 0.2-0.4Mpa, etc., and the top temperature of the distillation tower is 60-70°C, for example, 62-68°C, 64-66°C, etc.; then the reflux ratio is controlled to be 1:1-1.5, for example, 1:1.1-1.4, 1:1.2-1.3, etc., to perform distillation and remove the front fraction; when the difference between the temperature in the distillation kettle and the top temperature of the distillation tower is 25-35°C, for example, 28-32°C, etc., the distillation is completed to obtain a crude distillation product. Then, the crude distillation product is subjected to the distillation.

[0064] The present invention does not particularly limit the specific values ​​of the final temperature in the distillation kettle and the top temperature of the distillation tower. Generally, the reaction temperature will increase as the reaction proceeds, as long as the difference between the temperature in the distillation kettle and the top temperature of the distillation tower can be 25 to 35°C.

[0065] In the present invention, the main component of the fore fraction is water, and the fore fraction is collected first by distillation in order to control the purity and recovery rate of the organic solvent in the recovered solution.

[0066] Furthermore, the obtained front fraction can be collected separately, and sodium bicarbonate is added thereto to treat the cyanide ions in the front fraction, and then sent to a sewage station.

[0067] By using the method of rectification followed by redistillation to treat the wastewater of 1,4-diamino-2,3-dicyanoanthraquinone to obtain the recovered solution, it not only improves the efficiency of resource utilization, reduces energy consumption, but also reduces environmental pollution. It is an environmentally friendly and economical treatment method. It solves the problems of difficult degradation of low-concentration organic solvent wastewater, solvent loss, high recovery energy consumption, high operating costs, and low quality of recovered solutions, and truly achieves zero discharge of wastewater and recovery of production raw materials. After many verifications, as the mother liquor is purified and used as a solvent for the subsequent preparation of 1,4-diamino-2,3-dicyanoanthraquinone, it can still maintain a stable yield and purity. Other quality index requirements and environmental protection indicators also meet the requirements, and the standards of the recovered solution meet the expected use.

[0068] Furthermore, since dimethyl sulfoxide is an organic solvent with a high boiling point, the use of dimethyl sulfoxide as a solvent will cause energy consumption costs for subsequent distillation. In addition, compared with N,N-dimethylformamide (DMF), N,N-dimethylacetamide itself has low corrosiveness and low toxicity, which can effectively reduce the degree of occupational hazards to employees and the pollution index to the environment, and is more in line with environmental protection requirements. N,N-dimethylacetamide has good thermal stability and is stable and does not decompose even at boiling point (due to the introduction of ethyl in the molecular structure, the boiling point of N,N-dimethylacetamide is more than 10°C higher than that of N,N-dimethylformamide (the boiling point of N,N-dimethylformamide is 153°C), so N,N-dimethylacetamide has better thermal stability and chemical stability than N,N-dimethylformamide. In organic synthesis, N,N-dimethylacetamide is an excellent catalyst, which can accelerate reactions such as cyclization, halogenation, cyanation, alkylation and dehydrogenation, and can improve the yield of the main product. N,N-dimethylacetamide is also not easy to hydrolyze, which reduces the tendency of the formation of reaction by-products and effectively controls the product quality of the main product. Therefore, the present invention preferably uses N,N-dimethylacetamide as the organic solvent.

[0069] In some specific embodiments, the organic solvent can be derived from one or a combination of two or more of the following: ① process wastewater containing N,N-dimethylacetamide generated when all are Disperse Blue 165, Disperse Blue 165:1, or Disperse Blue 366; ② fresh N,N-dimethylacetamide; ③ process wastewater containing N,N-dimethylacetamide in the process of synthesizing 1,4-diamino-2,3-dicyanoanthraquinone.

[0070] Generally speaking, in the preparation processes of Disperse Blue 165, Disperse Blue 165:1, Disperse Blue 366 and 1,4-diamino-2,3-dicyanoanthraquinone, the process will produce wastewater (mainly water and organic solvent) containing organic solvents (such as N,N-dimethylacetamide). The wastewater containing organic solvents has certain toxicity and high stability. It is discharged into the external environment at will, which is not only a serious economic loss, but also causes serious harm to the environment. This feature causes the mother liquor to not meet the sewage discharge requirements and cannot be discharged directly. Therefore, the present invention can obtain a recovered solution containing an organic solvent by distilling the above-mentioned wastewater containing an organic solvent, which is used as an organic solvent for preparing 1,4-diamino-2,3-dicyanoanthraquinone in this application.

[0071] The preparation method of the present invention can effectively utilize process wastewater, which not only solves the problems of low recovery rate, solvent loss, high recovery energy consumption, high operating costs, and low quality of recovered solvents in wastewater containing low concentrations of organic solvents, but also produces less residue during the distillation of wastewater containing organic solvents, and the environmental protection cost is also reduced, thereby truly realizing zero discharge of wastewater and recovery of production raw materials.

[0072] By treating the process wastewater to a recovery solution with a mass concentration of 65-98% of organic solvent, and then using it again as a solvent in the cyanidation reaction, it can be recycled in a friendly manner, with low energy consumption, and truly achieve a significant reduction in production costs; and the target product of the cyanidation reaction using the recovery solution as a solvent can still maintain a stable yield and purity, and other quality index requirements and environmental protection indicators also meet the requirements. In addition, the use of the recovery solution also alleviates the pressure of subsequent waste liquid treatment.

[0073] In some specific embodiments, in step 1, the pH value is adjusted to 7 to 9.5 using an ammonia solution, preferably, the mass fraction of the ammonia solution is 5 to 25%. In the present invention, the ammonia solution can neutralize the sulfuric acid and hydrochloric acid introduced in the previous step, reducing the consumption of sodium cyanide. Too much ammonia solution will affect the forward reaction, so the pH value is controlled to be 7 to 9.5, for example: 7.5 to 9.0.

[0074] In some specific embodiments, step 2 includes: adding an oxidant to the mixed product, adjusting the temperature of the reaction system to 40-50°C, for example, 42-48°C, 44-46°C, etc.; then mixing with sodium cyanide, and adjusting the temperature of the reaction system to 70-75°C, for example, 71-74°C, 72-73°C, etc. for cyanidation reaction; and adding a alkali agent to the reaction system to adjust the pH value to obtain a cyanidation product containing 1,4-diamino-2,3-dicyanoanthraquinone. The inventors of the present invention have found that by mixing oxides, sodium cyanide and alkali agents at different temperatures, the cyanidation reaction can be better carried out.

[0075] In some specific embodiments, during the cyanidation reaction, the pH value of the reaction system is adjusted to 8 to 10.5, for example, 8.5 to 10, etc., and the cyanidation reaction is completed when the content of sulfonic acid in the reaction system is less than 2%. Because the cyanidation reaction itself will increase the pH of the system, the reaction requires the pH to be maintained within a certain range. By adjusting the pH value, the alkaline substances generated by the reaction are neutralized to prevent the generation of hydrogen cyanide gas, keep the reaction forward, and maintain the stability of the target product. Preferably, in the present invention, the time of the cyanidation reaction can be 8 to 15 hours, for example, 10 to 13 hours, 11 to 12 hours, etc.

[0076] In some specific embodiments, the mass ratio of the sodium cyanide to the 1,4-diamino-2-sulfonic anthraquinone is 0.3 to 1:1, for example, 0.4 to 0.9:1, 0.5 to 0.8:1, 0.6 to 0.7:1, etc. When the mass ratio of sodium cyanide to the 1,4-diamino-2-sulfonic anthraquinone is 0.3 to 1:1, it is beneficial to the cyanidation reaction and reduces the harm of sodium cyanide.

[0077] The mass ratio of the oxidant to the 1,4-diamino-2-sulfonic anthraquinone is 0.05 to 0.3:1, for example, 0.08 to 0.25:1, 0.1 to 0.2:1, 0.12 to 0.18:1, 0.14 to 0.16:1, etc. When the mass ratio of the oxidant to the 1,4-diamino-2-sulfonic anthraquinone is 0.05 to 0.3:1, the reaction can proceed better.

[0078] In some specific embodiments, the oxidant includes one or a combination of two or more of nitrobenzene, sodium m-nitrobenzene sulfonate, and sodium p-nitrobenzene sulfonate; the alkali-binding agent includes one or a combination of two or more of sulfuric acid, hydrochloric acid, and acetic acid. Preferably, in the present invention, the alkali-binding agent includes a sulfuric acid solution with a mass fraction of 20 to 40%.

[0079] In some specific embodiments, the preparation method further comprises step 3, wherein step 3 comprises washing the cyanide product with hot water at 50 to 95° C. to remove inorganic salts. In the present invention, hot water can be used to wash away inorganic salts, and filtering can separate and purify the target product.

[0080] Compared with the traditional process, the preparation method of the invention has clear process flow, simple operation and shortened production cycle. By adopting the simplified production process, the yield of the prepared 1,4-diamino-2,3-dicyanoanthraquinone is above 90.0% and the purity is above 95.0%.

[0081] The present invention also provides 1,4-diamino-2,3-dicyanoanthraquinone, which is prepared by the preparation method of the present invention, wherein the purity of the 1,4-diamino-2,3-dicyanoanthraquinone is above 95%, and the yield of the 1,4-diamino-2,3-dicyanoanthraquinone is above 90%.

[0082] In addition, the 1,4-diamino-2,3-dicyanoanthraquinone of the present invention has good industrial application prospects and can be widely used in the fields of dyes, medicines, pesticides, etc.

[0083] Example

[0084] The embodiments of the present invention will be described in detail below in conjunction with the examples, but those skilled in the art will appreciate that the following examples are only used to illustrate the present invention and should not be considered to limit the scope of the present invention. If no specific conditions are specified in the examples, they are carried out according to normal conditions or the conditions recommended by the manufacturer. If the manufacturer is not specified for the reagents or instruments used, they are all conventional products that can be obtained commercially.

[0085] In the examples, the purity of the product was determined by HPLC.

[0086] Example 1

[0087] The DMAc mother liquor from the product Disperse Blue 165 was pumped into the distillation kettle, the vacuum pump was turned on, the vacuum degree of the distillation kettle was maintained at -0.085 MPa, the steam inlet and outlet valves and the condenser cooling water inlet and outlet valves were opened, and when the temperature in the kettle reached 80°C, distillation began. At this time, the steam pressure was 0.2 MPa. As DMAc was continuously distilled out, the temperature in the kettle continued to rise. When DMAc was no longer distilled out, the temperature in the kettle was 121°C, the steam pressure was 0.45 MPa, the vacuum degree was -0.083 MPa, and the mass concentration of the obtained DMAc solution was 77.6%.

[0088] 2800kg of the DMAc solution (77.6%) recovered from the above-mentioned disperse blue 165 was added to the reactor, stirring was started, 1300kg (640kg in dry form) of 1,4-diamino-2-sulfonic anthraquinone with a mass fraction of 96.2% was added, and after stirring for half an hour, ammonia water with a mass fraction of 20.0% was added dropwise to adjust the pH value to 9.1, and the pH value was kept basically unchanged for half an hour, and the reaction system tended to a stable state, 85kg of nitrobenzene with a mass fraction of 98% was added to the reactor, and the temperature was adjusted to about 45°C, and then 1050kg of sodium cyanide solution with a mass fraction of 30% was added thereto, stirred for about 30 minutes, heated to about 72°C, and kept warm at about 72°C for 10 hours for cyanidation reaction. During the insulation period, 35% dilute sulfuric acid was used to continuously adjust the pH value of the solution to keep the pH of the reaction system at about 10. After the insulation was completed, the sampling test endpoint was taken: sulfonic acid <2% was qualified, and the cyanide product was obtained.

[0089] After the sampling test is qualified, the cyanide product is filtered and first washed with hot water at 90°C to remove inorganic salts to obtain a washed product; the washing liquid and the mother liquor are collected together and the DMAc solution is recovered by distillation; the washed product is then dried to obtain 562 kg of 1,4-diamino-2,3-dicyanoanthraquinone product, wherein the purity of the obtained product is 95.26% and the yield is 96.96%.

[0090] Example 2

[0091] The DMF mother liquor from the product Disperse Blue 165:1 was pumped into the distillation kettle, the vacuum pump was turned on, the vacuum degree of the distillation kettle was maintained at -0.083Mpa, the steam inlet and outlet valves and the condenser cooling water inlet and outlet valves were opened, and when the temperature in the kettle reached 75°C, distillation began, and the steam pressure was 0.18Mpa at this time. As DMF was continuously distilled out, the temperature in the kettle continued to rise. When DMF stopped distilling out, the temperature in the kettle was 117°C, the steam pressure was 0.42Mpa, the vacuum degree was -0.082Mpa, and the mass concentration of the obtained DMF solution was 74.3%.

[0092] 2920 kg of the above-mentioned disperse blue 165:1 recovered DMF solution (74.3%) was added into the reactor, stirring was started, 1210 kg (640 kg in dry form) of 1,4-diamino-2-sulfonic acid anthraquinone with a mass fraction of 96.4% was added, and after stirring for half an hour, 15.0% ammonia water was added dropwise to adjust the pH value to 9.2, and the pH value was kept basically unchanged for half an hour, and the reaction system tended to a stable state. 165 kg of sodium m-nitrobenzene sulfonate with a mass fraction of 91% was added into the reactor, and the temperature was adjusted to about 45°C, and then 1050 kg of sodium cyanide solution with a mass fraction of 30% was added thereto, and the temperature was stirred for about 30 minutes and raised to about 73°C, and kept at a temperature of about 73°C for 10 hours for cyanidation reaction. During the insulation period, 35% dilute sulfuric acid was used to continuously adjust the pH value of the solution to keep the pH of the reaction system at about 10. After the heat preservation is finished, sampling is performed to test the end point: sulfonic acid < 2% is qualified, and the cyanide product is obtained.

[0093] After the sampling test is qualified, the cyanide product is filtered and first washed with hot water at 90°C to remove inorganic salts to obtain a washed product; the washing liquid and the mother liquor are collected together and the DMF solution is recovered by distillation; the washed product is then dried to obtain 564 kg of 1,4-diamino-2,3-dicyanoanthraquinone product, wherein the purity of the obtained product is 95.38% and the yield is 97.31%.

[0094] Example 3

[0095] The DMAc mother liquor from the product Disperse Blue 366 was pumped into the distillation kettle, the vacuum pump was turned on, the vacuum degree of the distillation kettle was maintained at -0.088 MPa, the steam inlet and outlet valves and the condenser cooling water inlet and outlet valves were opened, and when the temperature in the kettle reached 82°C, distillation began. At this time, the steam pressure was 0.25 MPa. As DMAc was continuously distilled out, the temperature in the kettle continued to rise. When DMAc stopped distilling out, the temperature in the kettle was 123°C, the steam pressure was 0.46 MPa, the vacuum degree was -0.086 MPa, and the mass concentration of the obtained DMAc solution was 80.2%.

[0096] 2700kg of the DMAc solution (80.2%) recovered from the above-mentioned Disperse Blue 366 and 720kg of water were added to the reactor, stirring was started, and 1240kg (640kg in dry form) of 1,4-diamino-2-sulfonic anthraquinone with a mass fraction of 95.6% was added. After stirring for half an hour, 10.0% ammonia water was added dropwise to adjust the pH value to 9.1. The pH value was kept basically unchanged for half an hour, and the reaction system tended to a stable state. 85kg of 91% sodium m-nitrobenzene sulfonate and 40kg of nitrobenzene were added to the reactor, and the temperature was adjusted to 47°C. Then, 320kg of solid sodium cyanide with a mass fraction of 98% was added thereto, and the temperature was raised to 73°C after stirring for about 30 minutes, and the temperature was kept at about 73°C for 10 hours for cyanidation reaction. During the insulation period, 30% dilute sulfuric acid was used to continuously adjust the pH value of the solution to ensure that the pH of the solution was about 10. After the insulation is finished, sampling and testing the endpoint: sulfonic acid < 2% is qualified.

[0097] After the sampling test is qualified, the cyanide product is filtered and washed with hot water at 90°C to remove inorganic salts to obtain a washed product; the washing liquid and the mother liquor are collected together and the DMAc solution is recovered by distillation. The washed product is then dried to obtain 560 kg of 1,4-diamino-2,3-dicyanoanthraquinone product, wherein the purity of the obtained product is 95.78% and the yield is 96.61%.

[0098] Example 4

[0099] The collected DMAc mother liquor and washing liquid after the cyanation reaction were pumped into the distillation tower, the vacuum system and the cooling system were turned on to ensure that the vacuum degree was -0.075 MPa, and the steam inlet and outlet valves were opened to start full reflux for 10 minutes. At this time, the top temperature of the distillation tower was 66°C, the temperature in the distillation kettle connected to the distillation tower was 75°C, and the jacket steam pressure of the distillation kettle was 0.25 MPa. After the full reflux was completed, the reflux ratio was controlled to be 1:0.5 for distillation to evaporate the front fraction. The distillation was completed when the difference between the kettle temperature of the distillation kettle and the top temperature of the distillation tower was 30°C. At this time, the kettle temperature of the distillation kettle was 100°C, the top temperature of the distillation tower was 70°C, and the vacuum degree was -0.075 MPa to obtain a crude distillation product.

[0100] The above-mentioned crude distillation product is placed in a distillation kettle, and the vacuum pump is turned on to maintain the vacuum degree of the distillation kettle at -0.085 MPa. The steam inlet and outlet valves and the condenser cooling water inlet and outlet valves are opened. When the temperature in the kettle reaches 92° C., distillation begins. At this time, the steam pressure is 0.28 MPa. As the DMAc solution is continuously distilled out, the temperature in the kettle continues to rise. When DMAC is no longer distilled out, the temperature in the kettle is 125° C., the steam pressure is 0.51 MPa, and the vacuum degree is -0.086 MPa. The mass concentration of the DMAC solution obtained is 83.4%.

[0101] 2600kg of the recovered DMAC solution (83.4%) obtained by the above distillation and 200kg of water were added to the reactor, stirring was started, 1280kg (640kg in dry form) of 1,4-diamino-2-sulfonic anthraquinone with a mass fraction of 95.5% was added, and after stirring for half an hour, ammonia water with a mass fraction of 20.0% was added dropwise to adjust the pH value to 9.2, and the pH value was kept basically unchanged for half an hour, and the reaction system tended to a stable state, 85kg of nitrobenzene with a mass fraction of 98% was added to the reactor, and the temperature was adjusted to 46°C, and then 1050kg of sodium cyanide solution with a mass fraction of 30% was added thereto, stirred for about 30 minutes and heated to 73°C, and kept warm at a temperature of about 73°C for 10 hours for cyanidation reaction. During the insulation period, 35% dilute sulfuric acid was used to continuously adjust the pH value of the solution to keep the pH of the reaction system at about 10. After the insulation was completed, the sampling test endpoint was taken: sulfonic acid <2% was qualified, and the cyanide product was obtained.

[0102] After the sampling test is qualified, the cyanide product is filtered and first washed with hot water at 90°C to remove inorganic salts to obtain a washed product; the washing liquid and the mother liquor are collected together and the DMAc solution is recovered by distillation; the washed product is then dried to obtain 565 kg of 1,4-diamino-2,3-dicyanoanthraquinone product, wherein the purity of the obtained product is 95.29% and the yield is 97.47%.

[0103] Example 5

[0104] 900 kg of DMAc solution (80.2%) recovered from Disperse Blue 366 (DMAc solution obtained by distillation in Example 3), 1000 kg of DMAc solution (77.6%) recovered from Disperse Blue 165 (DMAc solution obtained by distillation in Example 1), 800 kg of DMAc solution (83.4%) recovered from 1,4-diamino-2,3-dicyanoanthraquinone (DMAc solution obtained by distillation after rectification in Example 4) and 100 kg of water were added into the reactor, stirring was started, and 1250 kg of 1,4-diamino-2-sulfonic acid anthraquinone (600 g, dry weight) with a content of 95.5% was added. 40kg), after stirring for half an hour, add 20.0% ammonia water to adjust the pH value to 9.2, keep the pH value basically unchanged for half an hour, and the reaction system tends to a stable state. Add 165kg of 98% sodium p-nitrobenzene sulfonate to the reactor, adjust the temperature to 46°C, then add 1050kg of 30% sodium cyanide solution, stir for about 30 minutes and heat to 73°C, and keep it at a temperature of about 73°C for 10 hours to carry out cyanidation reaction. During the insulation period, 35% dilute sulfuric acid is used to continuously adjust the pH value of the solution to keep the pH of the reaction system at about 10. After the insulation is completed, the sampling test end point: sulfonic acid <2% is qualified, and the cyanide product is obtained.

[0105] After the sampling test is qualified, the cyanide product is filtered and first washed with hot water at 90°C to remove inorganic salts to obtain a washed product; the washing liquid and the mother liquor are collected together and the DMAc solution is recovered by distillation; the washed product is then dried to obtain 564 kg of 1,4-diamino-2,3-dicyanoanthraquinone product, wherein the purity of the obtained product is 95.41% and the yield is 97.3%.

[0106] Example 6

[0107] Add 2180kg of fresh DMAc (99%) and 620kg of water to the reactor, start stirring, add 1260kg (640kg in dry form) of 1,4-diamino-2-sulfonic anthraquinone with a content of 95.8%, and after stirring for half an hour, add 20.0% ammonia water to adjust the pH value to 9.2, stabilize for half an hour to keep the pH value basically unchanged, and the reaction system tends to a stable state. Add 85kg of 98% nitrobenzene to the reactor, adjust the temperature to 46°C, and then add 1050kg of 30% sodium cyanide solution to it, stir for about 30 minutes, heat to 73°C, and keep it at a temperature of about 73°C for 10 hours for cyanidation reaction. During the insulation period, 35% dilute sulfuric acid is used to continuously adjust the pH value of the solution to keep the pH of the reaction system at about 10. After the insulation is completed, the sampling test end point: sulfonic acid <2% is qualified, and the cyanide product is obtained.

[0108] After the sampling test is qualified, the cyanide product is filtered and first washed with hot water at 90°C to remove inorganic salts to obtain a washed product; the washing liquid and the mother liquor are collected together and the DMAc solution is recovered by distillation; the washed product is then dried to obtain 563 kg of 1,4-diamino-2,3-dicyanoanthraquinone product, wherein the purity of the obtained product is 95.39% and the yield is 97.13%.

[0109] Comparative Example

[0110] After centrifugation of Disperse Blue 165, 3300 kg of DMAc mother liquor was added to the reactor, stirring was started, 1300 kg (640 kg in dry form) of 1,4-diamino-2-sulfonic anthraquinone with a mass fraction of 96.5% was added, and after stirring for half an hour, 20.0% ammonia water was added dropwise to adjust the pH value to 9.3, and the pH value was kept basically unchanged for half an hour, and the reaction system tended to a stable state. 85 kg of nitrobenzene with a mass fraction of 98% was added to the reactor, and the temperature was adjusted to about 45°C. Then, 1050 kg of sodium cyanide solution with a mass fraction of 30% was added thereto, and the temperature was stirred for about 30 minutes and heated to about 72°C, and the temperature was kept at about 72°C for 10 hours for cyanidation reaction. During the insulation period, 35% dilute sulfuric acid was used to continuously adjust the pH value of the solution to keep the pH of the reaction system at about 10. After the insulation was completed, the sampling test endpoint was taken: the sulfonic acid raw material was 36.5%, and the product was unqualified.

[0111] The product was filtered and washed with hot water at 90° C. to remove inorganic salts, thereby obtaining a washed product; the purity of the obtained product was 53.2%, and the product was unqualified.

[0112] It should be noted that, although the technical solution of the present invention is introduced with specific examples, those skilled in the art will appreciate that the present invention should not be limited thereto.

[0113] The embodiments of the present invention have been described above, and the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments. The selection of terms used herein is intended to best explain the principles of the embodiments, practical applications, or technical improvements in the market, or to enable other persons of ordinary skill in the art to understand the embodiments disclosed herein.

Claims

1. A method for preparing 1,4-diamino-2,3-dicyanoanthraquinone, characterized in that: The following steps are involved: Step 1: After mixing 1,4-diamino-2-sulfonic acid anthraquinone with a solvent, the pH value is adjusted to 7-9.5 to obtain a mixed product; Step 2: adding an oxidant, sodium cyanide and an alkali agent to the mixed product to carry out a cyanation reaction to obtain a cyanation product containing 1,4-diamino-2,3-dicyanoanthraquinone.

2. The preparation method according to claim 1, characterized in that: In step 1, the solvent includes a recovery solution; wherein the recovery solution is obtained by distilling process wastewater containing an organic solvent, and the organic solvent includes one or a combination of two or more of N,N-dimethylformamide, N,N-dimethylacetamide and dimethyl sulfoxide; Preferably, in the recovery solution, the mass concentration of the organic solvent is 65-98%; Optionally, the solvent further comprises an inorganic solvent; based on the total mass of the solvent, the content of the recovered solution is 70 to 99%; Further preferably, the distillation conditions include: adjusting the vacuum degree of the distillation kettle to -0.1 to -0.05 MPa and then raising the temperature to 70 to 150° C., and the steam pressure in the distillation kettle is 0.1 to 0.5 MPa; When the distillation is finished, the temperature in the still is 100-180°C, the vacuum degree is -0.1 to -0.05 MPa, and the steam pressure is 0.3 to 0.8 MPa.

3. The preparation method according to claim 2, characterized in that: Prior to the distillation, the method further comprises a rectification step; Preferably, the distillation comprises the step of collecting and removing the front fraction using a connected distillation tower and a distillation kettle to obtain a crude distillation product; More preferably, the distillation comprises: controlling the vacuum degree at the top of the distillation tower to -0.1 to -0.05 MPa for full reflux, preferably, the full reflux time is 5 to 20 min, the kettle temperature of the distillation kettle is 70 to 80°C, the jacket steam pressure of the distillation kettle is 0.1 to 0.5 MPa, and the top temperature of the distillation tower is 60 to 70°C; then controlling the reflux ratio to 1:0.1 to 1.5 for distillation and removing the front fraction; when the difference between the kettle temperature of the distillation kettle and the top temperature of the distillation tower is 25 to 35°C, the distillation is terminated to obtain a crude distillation product.

4. The preparation method according to any one of claims 1 to 3, characterized in that In the step 1, the pH value is adjusted to 7-9.5 using an ammonia solution. Preferably, the mass fraction of the ammonia solution is 5-25%.

5. The preparation method according to any one of claims 1 to 4, characterized in that: The step 2 comprises the following steps: The oxidant is added to the mixed product, and the temperature of the reaction system is adjusted to 40-50° C.; then, the mixed product is mixed with the sodium cyanide, and the temperature of the reaction system is adjusted to 70-75° C. for cyanidation reaction; and the alkali agent is added to the reaction system to adjust the pH value to obtain a cyanidation product containing 1,4-diamino-2,3-dicyanoanthraquinone.

6. The preparation method according to any one of claims 1 to 5, characterized in that: During the cyanation reaction, the pH value of the reaction system is 8 to 10.5, and the cyanation reaction is completed when the content of sulfonic acid in the reaction system is less than 2%; Preferably, the cyanation reaction time is 8 to 15 hours.

7. The preparation method according to any one of claims 1 to 6, characterized in that: The mass ratio of the sodium cyanide to the 1,4-diamino-2-sulfonic acid anthraquinone is 0.3 to 1:1; The mass ratio of the oxidant to the 1,4-diamino-2-sulfonic acid anthraquinone is 0.05 to 0.3:1; The sodium cyanide is added in the form of solid sodium cyanide or sodium cyanide solution. Preferably, the mass fraction of sodium cyanide in the sodium cyanide solution is 15-90%.

8. The preparation method according to any one of claims 1 to 7, characterized in that: The oxidant includes one or a combination of two or more of nitrobenzene, sodium m-nitrobenzene sulfonate, sodium p-nitrobenzene sulfonate; The alkali agent includes one or a combination of two or more of sulfuric acid, hydrochloric acid and acetic acid; Preferably, the alkali-binding agent comprises a sulfuric acid solution with a concentration of 20-40%.

9. The preparation method according to any one of claims 1 to 8, characterized in that: The preparation method further comprises step 3, wherein step 3 comprises the step of washing the cyanide product with hot water at 50 to 95° C. to remove inorganic salts.

10. A 1,4-diamino-2,3-dicyanoanthraquinone, characterized in that: It is prepared by the preparation method according to any one of claims 1 to 9, wherein the purity of the 1,4-diamino-2,3-dicyanoanthraquinone is above 95%, and the yield of the 1,4-diamino-2,3-dicyanoanthraquinone is above 90%.

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