Environment-friendly solvent green 3 production process and system

Abstract

The invention belongs to the technical field of chemical dye production, and particularly discloses an environment-friendly solvent green 3 production process and system.The environment-friendly solvent green 3 production process comprises the following steps that ethyl alcohol is added into a condensation kettle to serve as a solvent, p-methylaniline, 1, 4-dihydroxy anthraquinone, a 1, 4-dihydroxy anthraquinone leuco body, boric acid, lactic acid and anhydrous sodium sulfate are sequentially put into the condensation kettle, after feeding is completed, the kettle is closed, the temperature is raised, heat preservation is conducted, and the solvent green 3 is obtained; sampling and detecting an end point, adding DMF for separation, stirring and heating, preserving heat, cooling and filtering, taking a filter cake into a kettle, adding ethanol for soaking and washing the filter cake, pumping the ethanol, washing the filter cake with warm water, washing the filter cake with hot water until the filter cake is neutral, discharging and drying to obtain a solvent green 3 product, recovering the used ethanol and DMF, and carrying out distillation separation for reuse. According to the method, ethanol and DMF used in the production process of the solvent green 3 are recycled, so that waste of production resources is avoided, pollutants generated by a solvent in wastewater are reduced, and the production cost is reduced.

Description

Technical Field

[0001] The present invention belongs to the technical field of chemical dye production, and particularly relates to an environmentally friendly production process and system for solvent green 3. Background Art

[0002] Solvent green 3, also known as transparent green 5B, with the chemical name of 1,4-bis(4-methylphenyl)aminoanthraquinone, is a blue-black crystal or powder. It shows a blue color in concentrated sulfuric acid and produces a blue-green precipitate when diluted with water. Solvent green 3 is mainly used for coloring plastic resins and polyester fiber pulp, and can also be applied to the coloring of daily plastics, plexiglass, PVC packaging materials, industrial oils, printing inks, colored masterbatches, petroleum products, coatings, etc. In the production of solvent green 3, solvents are required. With the improvement of environmental awareness, the environmental performance requirements for solvents are getting higher and higher. In traditional production methods of solvent green 3, the solvents used are not recycled, resulting in serious waste of resources and large amounts of pollutant emissions. Therefore, it is of great practical significance to develop an environmentally friendly production method for solvent green 3. Summary of the Invention

[0003] The purpose of the present invention is to provide an environmentally friendly production process and system for solvent green 3 in which the solvent can be recycled and reused.

[0004] To achieve the above purpose, the technical solution of the present invention is: an environmentally friendly production process for solvent green 3, comprising the following steps:

[0005] (a) Add ethanol as a solvent to the reaction kettle, and sequentially add p-toluidine, 1,4-dihydroxyanthraquinone, 1,4-dihydroxyanthraquinone leuco body, boric acid, lactic acid, and anhydrous sodium sulfate. After the feeding is completed, close the kettle and raise the temperature. Raise the temperature to 88 - 92 °C in 1.5 - 2 hours, control the pressure in the kettle at 0.15 - 0.2 MPa, keep warm for 18 - 20 hours. After the heat preservation is completed, take a sample to detect the end point;

[0006] Among them, the mass ratio of 1,4-dihydroxyanthraquinone to ethanol is 1:(5 - 6), the mass ratio of 1,4-dihydroxyanthraquinone to p-toluidine and 1,4-dihydroxyanthraquinone leuco body is 1:(1.15 - 1.2):(0.2 - 0.3), and the mass ratio of 1,4-dihydroxyanthraquinone to boric acid, lactic acid, and anhydrous sodium sulfate is 1:(0.25 - 0.3):(0.1 - 0.2):(0.1 - 0.3);

[0007] (b) Wait for the reaction kettle to cool down until the pressure in the kettle is 0 MPa. Add N,N-dimethylformamide (DMF) to the reaction kettle for precipitation. Stir and raise the temperature to 118 - 122 °C, then keep warm for 1 hour. Subsequently, continue to raise the temperature to distill and separate DMF, collect all the distillates into the storage tank for recycling. After the distillation and separation of DMF are completed, cool down to 45 - 50 °C, and discharge the material to the filter tank for filtration to obtain a filter cake and a filtrate;

[0008] (c) Take the filter cake obtained in the above step b into a kettle, add ethanol to soak and wash the filter cake. After the ethanol soaking and washing is completed, drain the ethanol and then wash the filter cake with warm water in several times. Collect the soaking ethanol and washing water for recovery.

[0009] (d) Transfer the distillate and filtrate obtained in the above step b, and the soaking ethanol and washing water obtained in the above step c into the kettle of the rectification column, and rectify and separate to recover ethanol and DMF.

[0010] (e) Wash the filter cake after the warm water washing in the above step c with hot water until it is neutral, discharge the material, and dry it to obtain the solvent green 3 product.

[0011] Furthermore, in step a, the endpoint analysis method adopts thin-layer chromatography (TLC) method. The developing agent uses a mixed system of xylene and acetone, and the solvent uses chloroform. Control that there are no spots or trace purple spots in the developing layer as the endpoint.

[0012] Furthermore, starting from the second batch, the ethanol used in steps a and c, and the DMF used in step b are preferably the ethanol and DMF recovered in step d.

[0013] Furthermore, in step a, before adding materials into the reaction kettle, first displace the reaction kettle with nitrogen for 5 minutes.

[0014] The present invention also provides an environment-friendly solvent green 3 production system. The system includes a composite reaction kettle, a recovery storage tank, a rectification column kettle, a two-in-one filter, and a flash dryer. The discharge end of the composite reaction kettle is respectively connected with the two-in-one filter, the flash dryer, and the recovery storage tank through pipelines. The gas outlet of the composite reaction kettle is communicated with a first condenser. The output end of the first condenser and the filtrate outlet of the two-in-one filter are both communicated to the recovery storage tank. The liquid outlet end of the recovery storage tank is communicated with the feeding end of the rectification column kettle through a pipeline. The top of the rectification column kettle is communicated with a second condenser. The output end of the second condenser is respectively communicated with a recovered ethanol tank and a recovered DMF tank through pipelines.

[0015] The present invention has the following advantages compared with the prior art:

[0016] (1) The present invention recovers the used solvents ethanol and DMF in the production process of solvent green 3, and uses rectification to separate ethanol, water and DMF, and recycles them respectively after recovery, avoiding the waste of production resources, reducing the pollutants in the wastewater caused by the solvents, and reducing the production cost.

[0017] (2) In order to avoid the influence of the water mixed in the recycled ethanol on the condensation reaction for producing Solvent Green 3, the present invention additionally adds a water absorbent in the reaction kettle to remove the water mixed in the ethanol solvent, prevent the water content in the reaction system from being too high at the initial stage of the reaction to reduce the condensation reaction rate, and at the same time reduce the water content to avoid foaming of the materials, thereby preventing the yield of Solvent Green 3 produced by the process of the present invention from being reduced due to the use of recycled ethanol containing water;

[0018] (3) After the raw materials are condensed, DMF is added for segregation to refine and purify the product Solvent Green 3, ensuring the crystallization precipitation of the product Solvent Green 3 and improving the product yield. After refining the product with DMF, the product is washed with recycled ethanol again for secondary refining, further improving the quality of the Solvent Green 3 product produced by the process of the present invention. Brief Description of the Drawings

[0019] Figure 1 It is a schematic diagram of the system of the present invention.

[0020] In the figure: 1. Composite reaction kettle, 2. Recycling storage tank, 3. Distillation column kettle, 4. Two-in-one filter, 5. Flash dryer, 6. First condenser, 7. Second condenser, 8. Recycled ethanol tank, 9. Recycled DMF tank. Detailed Embodiments

[0021] The present invention will be further described below in conjunction with specific embodiments, but the protection scope of the present invention is not limited thereto.

[0022] In the synthesis process of Solvent Green 3 of the present invention, ethanol is used as the solvent, boric acid and lactic acid are used as catalysts, 1,4-dihydroxyanthraquinone leuco body is used as the initiator, and anhydrous sodium sulfate is used as the water absorbent. At the same time, ethanol can also be used as the water absorbent. 1,4-dihydroxyanthraquinone reacts with p-toluidine to obtain Solvent Green 3. DMF is added for refining to improve the product quality, and the product is washed with ethanol again to further improve the product quality. At the same time, the recycled ethanol and DMF are reused.

[0023] The main components of the distilled liquid, filtrate, washing ethanol and washing water recycled by the present invention are ethanol, DMF and water. During the rectification process, ethanol is separated first, followed by a small amount of water and then DMF. Among them, the main contents of the recycled ethanol and DMF are controlled to be above 98.5% to avoid the low content of the recycled ethanol or DMF affecting the reuse.

[0024] When using the rectification method to recycle ethanol, ethanol forms an azeotrope with water, resulting in a small amount of water mixed in the recycled ethanol. Therefore, anhydrous sodium sulfate is added as a water absorbent to absorb the water in the recycled ethanol in the reaction kettle, avoid the water content in the reaction system from being too high to reduce the condensation reaction rate, and prevent the foaming of the materials from causing the reduction of the yield of Solvent Green 3.

[0025] As Figure 1 shown, the system used in the above-mentioned environmentally friendly solvent green 3 production process includes a composite reactor 1, a recovery storage tank 2, a rectification column kettle 3, a two-in-one filter 4, and a flash dryer 5. Among them, the recovery storage tank 2 is used to store distillate, filtrate, pickling ethanol, and washing water for recycling; the rectification column kettle 3 uses an intermittent rectification column with a reactor; the two-in-one filter 4 performs pressure filtration and solid-liquid separation on the material after the reaction is completed; the flash dryer 5 is used to dry the product solvent green 3; the discharge end of the composite reactor 1 is respectively connected to the two-in-one filter 4, the flash dryer 5, and the recovery storage tank 2 through pipelines. The gas outlet of the composite reactor 1 is connected to a first condenser 6. The output end of the first condenser 6 and the filtrate outlet of the two-in-one filter 4 are both connected to the recovery storage tank 2. The liquid outlet end of the recovery storage tank 2 is connected to the feeding end of the rectification column kettle 3 through a pipeline. The top of the rectification column kettle 3 is connected to a second condenser 7. The output end of the second condenser 7 is respectively connected to a recovered ethanol tank 8 and a recovered DMF tank 9 through pipelines.

[0026] In the following multiple embodiments, the processes of recovering distillate, filtrate, pickling ethanol, and washing water and distilling and separating ethanol and DMF are the same. Unless otherwise specified, the raw materials used in the embodiments are all commercially available industrial products suitable for the production of dyes and intermediates.

[0027] Example 1

[0028] Add 3000 kg of fresh ethanol to the composite reactor, and successively add 640 kg of p-toluidine, 555 kg of 1,4-dihydroxyanthraquinone, 140 kg of 1,4-dihydroxyanthraquinone leuco body, 150 kg of boric acid, 80 kg of lactic acid, and 80 kg of anhydrous sodium sulfate. After feeding, close the feeding valve, close the kettle and heat up. Heat up to 88 °C in 1.5 hours, control the pressure in the kettle at 0.15 MPa, keep warm under this condition for R = 18 hours, and after the heat preservation is over, take a sample to detect the end point.

[0029] Wait for the composite reactor to cool down and depressurize. When the pressure in the kettle drops to 0 MPa, add 2000 kg of fresh DMF to the composite reactor to separate the product, stir and heat up to 118 °C, keep warm for 1 hour, heat up and distill to separate DMF, collect the distillate during the period and store it in the storage tank for recovery. After the distillation separation is over, cool down to 45 °C, discharge to the filter tank for filtration to obtain a filter cake and filtrate, and recycle the filtrate.

[0030] Put the filter cake into a compound reactor, add 2,000 kg of fresh ethanol for soaking and washing. It can be soaked and washed in batches according to the capacity of the reactor. After the soaking and washing are completed, drain the ethanol and recycle it. After washing the filter cake with warm water, recycle the warm water washing water. Wash the filter cake with hot water again until it is neutral, discharge it, dry it, and weigh it to obtain 1,165 kg of the target product, solvent green 3. The product purity is 98.5%, and the yield (based on the total of 1,4-dihydroxyanthraquinone and 1,4-dihydroxyanthraquinone leuco body) is 96.4%, with a Δc of 0.42 in terms of brilliance.

[0031] Example 2

[0032] This example is basically the same as Example 1 in terms of the input amount of materials and process steps. The difference is that: at the initial feeding, 1,500 kg of recycled ethanol and 1,500 kg of fresh ethanol are added to the compound reactor in sequence. Finally, after drying and weighing, 1,154 kg of the target product, solvent green 3, is obtained. The product purity is 98.1%, the yield is 95.5%, and the Δc is 0.35 in terms of brilliance.

[0033] Example 3

[0034] This example is basically the same as Example 1 in terms of the input amount of materials and process steps. The difference is that: at the initial feeding, 2,800 kg of recycled ethanol and 150 kg of anhydrous sodium sulfate are added to the compound reactor. Finally, after drying and weighing, 1,163 kg of the target product, solvent green 3, is obtained. The product purity is 98.4%, the yield is 96.2%, and the Δc is 0.36 in terms of brilliance.

[0035] Example 4

[0036] This example is basically the same as Example 1 in terms of the input amount of materials and process steps. The difference is that: at the initial feeding, 3,200 kg of recycled ethanol is added to the compound reactor. When the pressure in the compound reactor drops to 0 MPa, 2,000 kg of recycled DMF is added to the compound reactor to segregate the product. After the product is filtered, the filter cake is put into the compound reactor and washed with 2,000 kg of recycled ethanol. Finally, after drying and weighing, 1,123 kg of the target product, solvent green 3, is obtained. The product purity is 98.1%, the yield is 92.9%, and the Δc is 0.34 in terms of brilliance.

[0037] Example 5

[0038] This example is basically the same as Example 1 in terms of the material input and process steps. The differences are as follows: At the initial feeding, 3000 kg of recycled ethanol is added to the compound reaction kettle, and 140 kg of anhydrous sodium sulfate is added. When the pressure in the compound reaction kettle drops to 0 MPa, 2000 kg of recycled DMF is added to the compound reaction kettle to segregate the product. After the product is filtered, the filter cake is put into the compound reaction kettle, and 2000 kg of recycled ethanol is added for leaching. Finally, after drying and weighing, 1162 kg of solvent green 3 is obtained as the target product, with a product purity of 98.3% and a yield of 96.1%, and Δc is 0.37 in terms of brightness.

[0039] Example 6

[0040] Add 3100 kg of recycled ethanol to the compound reaction kettle, and successively add 665 kg of p-toluidine, 560 kg of 1,4-dihydroxyanthraquinone, 160 kg of the leuco body of 1,4-dihydroxyanthraquinone, 165 kg of boric acid, 105 kg of lactic acid, and 165 kg of anhydrous sodium sulfate. After the feeding is completed, close the feeding valve, close the kettle and heat up. It takes 2 hours to heat up to 92 °C, and control the pressure in the kettle at 0.2 MPa. Keep the temperature at this condition for R = 20 hours. After the heat preservation is over, take a sample to detect the end point.

[0041] When the compound reaction kettle cools down and the pressure drops to 0 MPa, add 2000 kg of recycled DMF to the compound reaction kettle to segregate the product. Stir and heat up to 122 °C, keep the temperature for 1 hour, heat up and distill to separate DMF, collect the distillate during the period and store it in the storage tank for recycling. After the distillation separation is over, cool down to 50 °C, discharge the material to the filter tank for filtration to obtain the filter cake and the filtrate, and recycle the filtrate.

[0042] Put the filter cake into the compound reaction kettle, add 2000 kg of recycled ethanol for leaching. It can be leached in batches according to the capacity of the kettle. After the leaching is over, drain the ethanol and recycle it. Wash the filter cake with warm water and recycle the warm water washing water. Wash the filter cake with hot water again until it is neutral, discharge the material, dry it, and weigh it to obtain 1211 kg of solvent green 3 as the target product, with a product purity of 98.3% and a yield of 96.7%, and Δc is 0.39 in terms of brightness.

[0043] Example 7

[0044] Add 2800 kg of recycled ethanol to the compound reaction kettle, and successively add 610 kg of p-toluidine, 520 kg of 1,4-dihydroxyanthraquinone, 130 kg of the leuco body of 1,4-dihydroxyanthraquinone, 140 kg of boric acid, 80 kg of lactic acid, and 140 kg of anhydrous sodium sulfate. After the feeding is completed, close the feeding valve, close the kettle and heat up. It takes 1.8 hours to heat up to 90 °C, and control the pressure in the kettle at 0.17 MPa. Keep the temperature at this condition for R = 19 hours. After the heat preservation is over, take a sample to detect the end point.

[0045] Wait for the composite reactor to cool down and reduce the pressure. When the pressure inside the reactor drops to 0 MPa, add 2000 kg of recycled DMF into the composite reactor to segregate the product. Stir and heat up to 120 °C, keep the temperature for 1 hour, then heat up for distillation to separate DMF. Collect the distillate during the distillation process and store it in a storage tank for recycling. After the distillation separation is completed, cool down to 48 °C, discharge the material to a filter tank for filtration to obtain a filter cake and filtrate, and recycle the filtrate.

[0046] Put the filter cake into the composite reactor, add 2000 kg of recycled ethanol for soaking and washing. The soaking and washing can be carried out in batches according to the capacity of the reactor. After the soaking and washing are completed, drain the ethanol and recycle it. Wash the filter cake with warm water and recycle the warm water washing water. Then wash the filter cake with hot water again until it is neutral, discharge the material, dry it, weigh it, and obtain 1088 kg of solvent green 3 as the target product. The product purity is 98.4%, the yield is 96.2%, and ⊿c is 0.4 bright.

[0047] The above embodiments are only used to illustrate the technical concept and features of the present invention, and their purpose is to enable those who are familiar with this technology to understand the content of the present invention and implement it accordingly, and it cannot be used to limit the protection scope of the present invention. All equivalent changes or modifications made according to the spirit and essence of the present invention should be covered within the protection scope of the present invention.

Claims

1. An environmentally friendly solvent green 3 production process, characterized in that, It includes the following steps: (a) Add ethanol as a solvent into the reaction kettle, and successively put in p-toluidine, 1,4-dihydroxyanthraquinone, leuco body of 1,4-dihydroxyanthraquinone, boric acid, lactic acid, and anhydrous sodium sulfate. After the feeding is completed, close the kettle and heat it up. Heat it to 88-92 °C in 1.5-2 hours, control the pressure in the kettle at 0.15-0.2 MPa, keep the temperature for 18-20 hours. After the heat preservation is completed, take a sample to detect the end point; Among them, the mass ratio of 1,4-dihydroxyanthraquinone to ethanol is 1:(5-6), the mass ratio of 1,4-dihydroxyanthraquinone to p-toluidine and leuco body of 1,4-dihydroxyanthraquinone is 1:(1.15-1.2):(0.2-0.3), and the mass ratio of 1,4-dihydroxyanthraquinone to boric acid, lactic acid, and anhydrous sodium sulfate is 1:(0.25-0.3):(0.1-0.2):(0.1-0.3); (b) Wait for the reaction kettle to cool down until the pressure in the kettle is 0 MPa. Add N,N-dimethylformamide (DMF) to the reaction kettle for precipitation. Stir and heat it up to 118-122 °C, then keep the temperature for 1 hour. Subsequently, continue to heat up for distillation to separate DMF. Collect all the distillate into the storage tank for recycling. After the distillation separation of DMF is completed, cool it down to 45-50 °C, discharge it to the filter tank for filtration to obtain a filter cake and a filtrate; (c) Take the filter cake obtained in the above step b into the reaction kettle, add ethanol to wash the filter cake by soaking. After the ethanol soaking and washing is completed, drain the ethanol and then wash the filter cake with warm water in several times. Collect the soaking ethanol and washing water for recycling; (d) Transfer the distillate, filtrate obtained in the above step b, and the soaking ethanol and washing water obtained in the above step c into the rectification tower kettle for rectification separation to recover ethanol and DMF; (e) Wash the filter cake after the warm water washing in the above step c with hot water until it is neutral, discharge it, and dry it to obtain the solvent green 3 product.

2. The production process of the environmentally friendly solvent Green 3 according to claim 1, characterized in that: In step a, the end point analysis method uses thin layer chromatography (TLC) method. The developing agent uses a mixed system of xylene and acetone, and the solvent uses chloroform. Control that there are no spots or trace purple spots in the developing layer as the end point.

3. The production process of environmentally friendly solvent green 3 according to claim 1, characterized in that: Starting from the second batch, the ethanol used in steps a and c, and the DMF used in step b, preferably use the ethanol and DMF recovered in step d.

4. The environmentally friendly solvent green 3 production process according to claim 1, characterized in that: In step a, before adding the materials into the reaction kettle, first use nitrogen to displace the reaction kettle for 5 minutes.

5. An environmentally friendly solvent green 3 production system, characterized in that: The system includes a composite reaction kettle (1), a recovery storage tank (2), a rectification tower kettle (3), a two-in-one filter (4), and a flash dryer (5). The discharge end of the composite reaction kettle (1) is respectively connected to the two-in-one filter (4), the flash dryer (5), and the recovery storage tank (2) through pipelines. The gas outlet of the composite reaction kettle (1) is connected to a first condenser (6). The output end of the first condenser (6) and the filtrate outlet of the two-in-one filter (4) are both connected to the recovery storage tank (2). The liquid outlet end of the recovery storage tank (2) is connected to the feeding end of the rectification tower kettle (3) through a pipeline. The top of the rectification tower kettle (3) is connected to a second condenser (7). The output end of the second condenser (7) is respectively connected to a recovered ethanol tank (8) and a recovered DMF tank (9) through pipelines.

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