Method for treating mother liquor in preparation process of 4, 6-diamino resorcinol hydrochloride
By distillation and recycling methanol and hydrochloric acid, and using high-temperature incineration to treat residues, the problem of incomplete mother liquor treatment in the preparation of 4,6-diaminosorcinol hydrochloride is solved, and efficient recycling and reducing solid waste emissions are achieved. Energy-saving and environmentally friendly production requirements.
Patent Information
- Application Number
- CN202310690535.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2023-06-12
- Publication Date
- 2024-12-13
AI Technical Summary
During the preparation of 4,6-diaminoisosorcinol hydrochloride, the methanol mother liquor and recrystallization mother liquor were not thoroughly treated, resulting in low solvent recovery efficiency and increased solid waste emissions.
Methanol and hydrochloric acid are recovered by distillation, and the residue after multiple distillations and rectifications are subjected to high-temperature incineration. The incineration temperature is controlled to be 700-950℃, and the residence time is 40-80 minutes. The residue is thoroughly treated.
It realizes efficient recycling of methanol and hydrochloric acid, reduces production costs, solves the problem of treating high-concentration chloride ion salt-containing wastewater, and meets the energy-saving and environmentally friendly production requirements.
Smart Images
Figure CN119118794A_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of organic wastewater treatment, and specifically relates to a method for treating a salt-forming methanol mother liquor and a recrystallization mother liquor in the process of preparing 4,6-diaminoresorcinol hydrochloride. Background Art
[0002] PBO fiber (poly(p-phenylene benzobisoxazole)) is known as the king of fibers because of its excellent performance. PBO fiber is prepared by the polymerization reaction of terephthalic acid and 4,6-diaminoresorcinol (DAR) hydrochloride. Since it is a polymerization reaction, the purity of the monomer is very high. The presence of impurities may lead to the termination of the polymerization reaction, reduce the degree of polymerization, and reduce the performance of the polymer material. Therefore, the purity of the monomer plays an important role in the preparation of high-performance PBO fibers.
[0003] At present, the preparation methods of DAR hydrochloride are mainly divided into 1,2,3-trichlorobenzene method and resorcinol method according to the raw materials. Among them, the DAR prepared by the former through nitration, hydrolysis, hydrogenation, crystallization and other processes has higher purity because no isomers are generated.
[0004] In the hydrogenation reaction process, 2-chloro-4,6-dinitroresorcinol is hydrogenated and dechlorinated under the action of a catalyst and a dechlorination promoter to generate 4,6-diaminoresorcinol. The 4,6-diaminoresorcinol in the hydrogenation liquid reacts with hydrochloric acid to form a salt which is precipitated from the mother liquor. The salt-forming liquid is filtered and separated to obtain a crude DAR hydrochloride containing a catalyst. This crude product is subjected to catalyst removal and recrystallization and refinement to prepare 4,6-diaminoresorcinol hydrochloride. There are two mother liquors in the whole treatment process, namely, the methanol mother liquor from which the hydrochloride is precipitated after the salt formation and the mother liquor of the recrystallization of 4,6-diaminoresorcinol hydrochloride. The methanol mother liquor contains methanol, 4,6-diaminoresorcinol hydrochloride, ammonium chloride, hydrochloric acid and stannous chloride, and the crystallization mother liquor contains hydrochloric acid, 4,6-diaminoresorcinol hydrochloride, stannous chloride and water. After the two mother liquors are distilled to recover the solvent and hydrochloric acid, a certain amount of residue is generated.
[0005] The present invention proposes a treatment method for the two mother liquors, recovers usable components, reduces the discharge of "three wastes", and completely treats the waste liquid in the entire post-treatment process. Summary of the invention
[0006] The technical problem to be solved by the present invention is as follows: the two mother liquors produced in the process of preparing 4,6-diaminoresorcinol hydrochloride are distilled to recover the solvent and hydrochloric acid, the usable methanol and hydrochloric acid are recovered, and the evaporation residue is treated by high-temperature incineration to reduce the emission of "solid waste".
[0007] The object of the present invention is to provide a method for treating methanol mother liquor and recrystallization mother liquor in the preparation process of 4,6-diaminoresorcinol hydrochloride.
[0008] The present invention is achieved by: a method for treating a mother liquor in the process of preparing 4,6-diaminoresorcinol hydrochloride, characterized in that the method is a method for treating a salt-forming methanol mother liquor and a recrystallization mother liquor in the process of preparing 4,6-diaminoresorcinol hydrochloride, comprising the following steps: A. Distill the methanol mother liquor precipitated from the hydrochloride to recover the crude methanol; B. The recovered crude methanol is distilled and the distilled methanol can be directly used as a solvent for hydrogenation reaction; C. Distill the recrystallization mother liquor to recover hydrochloric acid.
[0009] Furthermore, crude methanol is recovered by distillation of methanol mother liquor, and the heating temperature is controlled at 100-120°C.
[0010] Furthermore, in the crude methanol distillation process, the bottom temperature of the distillation kettle is 90-98°C.
[0011] Furthermore, in the crude methanol distillation process, the reflux ratio is 1.5:1-3.5:1.
[0012] Furthermore, the recrystallization mother liquor is distilled to recover hydrochloric acid, and the heating temperature is controlled to be 130-140°C.
[0013] Furthermore, the hydrochloric acid concentration recovered from the recrystallization mother liquor is 8%-12%, which can be directly used in the salt-forming step after the hydrogenation reaction.
[0014] Furthermore, the residues from multiple distillations and rectifications are mixed and then put into a high-temperature incineration treatment device for treatment.
[0015] Furthermore, the conditions for treating the residue in the high temperature incineration treatment device are: a temperature of 700-950°C and a residence time in the combustion chamber of 40-80 minutes.
[0016] Further preferably, the high temperature incineration treatment device treats the residue under the following conditions: a temperature of 800-950° C. and a residence time in the combustion chamber of 50-60 min.
[0017] The beneficial effects of the present invention are: The treatment method of the present invention thoroughly treats two mother liquors in the process of preparing 4,6-diaminoresorcinol hydrochloride by hydrogenation, recovers available effective components, and reduces production costs. The method effectively solves the treatment of high-concentration chloride ion-containing salt wastewater, solves the problem of wastewater treatment, and fully meets the production requirements of energy conservation and environmental protection. BRIEF DESCRIPTION OF THE DRAWINGS
[0018] Figure 1 The figure is a flow chart of a processing method according to an embodiment of the present invention. Implementation
[0019] The processing method of the present invention is described in detail below in conjunction with the embodiments and drawings.
[0020] The following examples are for reference Figure 1 . Example
[0021] Place a 1000ml four-necked flask on the stirrer, place the flask in a heating device, control the heating temperature to 100℃, and distill to recover crude methanol. 600ml of methanol mother liquor recovers 465ml of crude methanol. The purity of crude methanol is 90%. Add the crude methanol to the distillation device for distillation, and recover 350ml of refined methanol. The purity of methanol is 96%, which can be directly used as a solvent in hydrogenation experiments. Set the residue aside after distillation.
[0022] Put another 1000ml four-necked flask on the stirrer, put the flask into the heating device, add 650ml of recrystallization mother liquor into the flask, control the heating temperature to 135℃ to recover hydrochloric acid. 352ml of hydrochloric acid is recovered from 650ml of recrystallization mother liquor, and the concentration of hydrochloric acid is 8%.
[0023] The distillation residues after the two treatments are mixed and put into a high-temperature incineration device for treatment.
[0024] The conditions for treating distillation and rectification residues in the high-temperature incineration treatment device are: a temperature of 800°C and a residence time of 40 minutes in the combustion chamber. Example
[0025] Place a 1000ml four-necked flask on the stirrer, put the flask into the heating device, control the heating temperature to 105℃, and distill to recover crude methanol. 500ml of methanol mother liquor recovers 405ml of crude methanol. The purity of crude methanol is 92%. Add the crude methanol to the distillation device for distillation, and recover 320ml of refined methanol. The purity of methanol is 96%, which can be directly used as a solvent in hydrogenation experiments. Set the residue aside after distillation.
[0026] Put another 1000ml four-necked flask on the stirrer, put the flask into the heating device, add 650ml of recrystallization mother liquor into the flask, control the heating temperature to 130℃ to recover hydrochloric acid. 352ml of hydrochloric acid is recovered from 650ml of recrystallization mother liquor, and the concentration of hydrochloric acid is 9%.
[0027] The distillation residues after the two treatments are mixed and put into a high-temperature incineration device for treatment.
[0028] The conditions for treating distillation and rectification residues in the high-temperature incineration treatment device are: a temperature of 800°C and a residence time of 50 minutes in the combustion chamber. Example
[0029] Place a 1000ml four-necked flask on the stirrer, place the flask in a heating device, control the heating temperature to 110℃, and distill to recover crude methanol. 600ml of methanol mother liquor recovers 450ml of crude methanol. The purity of crude methanol is 92%. Add the crude methanol to the distillation device for distillation, and recover 370ml of refined methanol. The purity of methanol is 96%, which can be directly used as a solvent in hydrogenation experiments. Set the residue aside after distillation.
[0030] Put another 1000ml four-necked flask on the stirrer, put the flask into the heating device, add 650ml of recrystallization mother liquor into the flask, control the heating temperature to 130℃ to recover hydrochloric acid. 352ml of hydrochloric acid is recovered from 650ml of recrystallization mother liquor, and the concentration of hydrochloric acid is 9%.
[0031] The distillation residues after the two treatments are mixed and put into a high-temperature incineration device for treatment.
[0032] The conditions for treating distillation and rectification residues in the high-temperature incineration treatment device are: a temperature of 850°C and a residence time of 60 minutes in the combustion chamber. Example
[0033] Place a 1000ml four-necked flask on the stirrer, put the flask into the heating device, control the heating temperature to 115℃, and distill to recover crude methanol. 500ml of methanol mother liquor recovers 415ml of crude methanol. The purity of crude methanol is 92%. Add the crude methanol to the distillation device for distillation, and recover 340ml of refined methanol. The purity of methanol is 96%, which can be directly used as a solvent in hydrogenation experiments. Set the residue aside after distillation.
[0034] Put another 1000ml four-necked flask on the stirrer, put the flask into the heating device, add 650ml of recrystallization mother liquor into the flask, control the heating temperature to 135℃ to recover hydrochloric acid. 432ml of hydrochloric acid is recovered from 650ml of recrystallization mother liquor, and the concentration of hydrochloric acid is 10%.
[0035] The distillation residues after the two treatments are mixed and put into a high-temperature incineration device for treatment.
[0036] The conditions for treating distillation and rectification residues in the high-temperature incineration treatment device are: temperature 850°C and residence time in the combustion chamber of 70 minutes. Example
[0037] Place a 1000ml four-necked flask on the stirrer, put the flask into the heating device, control the heating temperature to 115℃, and distill to recover crude methanol. 550ml of methanol mother liquor recovers 455ml of crude methanol. The purity of crude methanol is 92%. Add the crude methanol to the distillation device for distillation, and recover 350ml of refined methanol. The purity of methanol is 96%, which can be directly used as a solvent in hydrogenation experiments. Set the residue aside after distillation.
[0038] Put another 1000ml four-necked flask on the stirrer, put the flask into the heating device, add 650ml of recrystallization mother liquor into the flask, control the heating temperature to 135℃ to recover hydrochloric acid. 352ml of hydrochloric acid is recovered from 650ml of recrystallization mother liquor, and the concentration of hydrochloric acid is 10%.
[0039] The distillation residues after the two treatments are mixed and put into a high-temperature incineration device for treatment.
[0040] The conditions for treating distillation and rectification residues in the high-temperature incineration treatment device are: a temperature of 900°C and a residence time of 50 minutes in the combustion chamber. Example
[0041] Place a 1000ml four-necked flask on the stirrer, put the flask into the heating device, control the heating temperature to 120℃, and distill to recover crude methanol. 500ml of methanol mother liquor recovers 415ml of crude methanol. The purity of crude methanol is 92%. Add the crude methanol to the distillation device for distillation, and recover 345ml of refined methanol. The purity of methanol is 96%, which can be directly used as a solvent in hydrogenation experiments. Set the residue aside after distillation.
[0042] Put another 1000ml four-necked flask on the stirrer, put the flask into the heating device, add 650ml of recrystallization mother liquor into the flask, control the heating temperature to 135℃ to recover hydrochloric acid. 375ml of hydrochloric acid is recovered from 650ml of recrystallization mother liquor, and the concentration of hydrochloric acid is 12%.
[0043] The distillation residues after the two treatments are mixed and put into a high-temperature incineration device for treatment.
[0044] The conditions for treating distillation and rectification residues in the high-temperature incineration treatment device are: a temperature of 950°C and a residence time of 70 minutes in the combustion chamber. Example
[0045] Place a 1000ml four-necked flask on the stirrer, put the flask into the heating device, control the heating temperature to 120℃, and distill to recover crude methanol. 500ml of methanol mother liquor recovers 420ml of crude methanol. The purity of crude methanol is 92%. Add the crude methanol to the distillation device for distillation, and recover 335ml of refined methanol. The purity of methanol is 96%, which can be directly used as a solvent in hydrogenation experiments. Put the residue after distillation aside.
[0046] Put another 1000ml four-necked flask on the stirrer, put the flask into the heating device, add 650ml of recrystallization mother liquor into the flask, control the heating temperature to 140℃ to recover hydrochloric acid. 378ml of hydrochloric acid is recovered from 650ml of recrystallization mother liquor, and the concentration of hydrochloric acid is 11%.
[0047] The distillation residues after the two treatments are mixed and put into a high-temperature incineration device for treatment.
[0048] The conditions for treating distillation and rectification residues in the high-temperature incineration treatment device are: a temperature of 850°C and a residence time of 80 minutes in the combustion chamber.
Claims
1. A method for treating mother liquor in the preparation process of 4,6-diaminoresorcinol hydrochloride, characterized in that The method for treating the salt-forming methanol mother liquor and the recrystallization mother liquor in the preparation process of 4,6-diaminoresorcinol hydrochloride comprises the following steps: A. Distill the methanol mother liquor precipitated from the hydrochloride to recover the crude methanol; B. The recovered crude methanol is distilled and the distilled methanol is directly used as the solvent for the hydrogenation reaction; C. Distill the recrystallization mother liquor to recover hydrochloric acid.
2. The processing method according to claim 1, characterized in that The methanol mother liquor is distilled to recover crude methanol, and the heating temperature is controlled at 100-120°C.
3. The processing method according to claim 1, characterized in that During the crude methanol distillation process, the bottom temperature of the distillation kettle is 90-98°C.
4. The processing method according to claim 1 or 3, characterized in that Crude methanol distillation process, reflux ratio: 1.5:1-3.5:
1.
5. The processing method according to claim 1, characterized in that The mother liquor of recrystallization is distilled to recover hydrochloric acid, and the heating temperature is controlled to be 130-140°C.
6. The processing method according to claim 1 or 5, characterized in that The hydrochloric acid concentration recovered from the recrystallization mother liquor is 8%-12%, which is directly used in the salt-forming step after the hydrogenation reaction.
7. The processing method according to claim 1, characterized in that The residues from multiple distillations and rectifications are mixed and then put into a high-temperature incineration treatment device for treatment.
8. The processing method according to claim 7, characterized in that The conditions for treating the residue in the high-temperature incineration treatment device are a temperature of 700-950°C and a residence time in the combustion chamber of 40-80 minutes.
9. The processing method according to claim 8, characterized in that The conditions for treating the residue in the high temperature incineration treatment device are: temperature 800-950℃, and residence time in the combustion chamber is 50-60min.