CN113072473A - Clean production method for substituted thiourea - Google Patents
Clean production method for substituted thiourea Download PDFInfo
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- CN113072473A CN113072473A CN202110398164.4A CN202110398164A CN113072473A CN 113072473 A CN113072473 A CN 113072473A CN 202110398164 A CN202110398164 A CN 202110398164A CN 113072473 A CN113072473 A CN 113072473A
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- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C335/00—Thioureas, i.e. compounds containing any of the groups, the nitrogen atoms not being part of nitro or nitroso groups
- C07C335/04—Derivatives of thiourea
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Abstract
The invention discloses a clean production method for replacing thiourea, which comprises the following steps: s1, adding materials; s2, reacting; s3, centrifuging; s4, preparing substituted thiourea; s5, treating filtrate C; s6, concentrating an ammonium sulfate solution; s7, extracting ammonium sulfate; s8, extracting ammonium thiocyanate; s9, recovering mother liquor N; s10, recovering a washing solution F; s11, supplementing ammonium thiocyanate; and S12, supplementing deionized water. According to the clean production method for replacing thiourea, water resources are recycled and used as process water, so that the water consumption is reduced, the production wastewater of replacing thiourea is thoroughly solved, and a zero-emission clean production mode is realized.
Description
Technical Field
The invention relates to a production method of substituted thiourea, in particular to a clean production method for substituted thiourea.
Background
Thiourea compounds are widely used in the chemical industry and are important raw materials and intermediates. The compound is usually used as a nitrogen fertilizer synergist in agriculture, and can also be used for preventing and controlling citrus mildew, the inhibition of the germination period of potatoes and the like; is mainly used for producing thiazole medicaments in industry. In addition, the hydrocarbyl thiourea compound is an important sulfide ore collecting agent and an important analysis reagent. One of the most used nonmetal stabilizers at present is 1, 3-diphenyl thiourea in aryl thiourea, which can be used as a medium-speed vulcanization accelerator in the preparation of natural rubber and synthetic rubber, and can also be used as a metal preservative, an analysis reagent of ruthenium, osmium and other elements, and the like; acylthioureas are also widely used in antifungal, antiviral, herbicidal, and plant growth regulating fields. The thiourea and the derivative thereof have wide application in the aspects of electrochemical analysis, spectrophotometric analysis, atomic absorption spectrum analysis, separation and enrichment and the like of noble metals due to unique molecular structures.
A common process for producing substituted thiourea is to react organic amine, ammonium thiocyanate and sulfuric acid. The process produces a wastewater comprising unreacted organic amine, residual product, ammonium thiocyanate, free sulfuric acid, ammonium sulfate. The direct discharge of waste water not only causes resource waste of unreacted and complete substances, but also has the toxicity of ammonium thiocyanate, the minimum lethal dose (mice, oral administration) of 330mg/kg, irritation, harm to the environment and pollution to water.
Patent CN201510903547 discloses a method for treating 4-methyl-2-hydrazinobenzothiazole production wastewater, which can remove part of harmful substances by removing organic substances through resin adsorption, removing ammonium thiocyanate through adding an oxidant, and obtaining ammonium sulfate through salting out and evaporation.
Disclosure of Invention
The invention provides a clean production method which is more environment-friendly, extremely high in resource utilization rate, simple to operate, economical and environment-friendly, and aims to solve the problems of improper wastewater treatment and resource waste in the production process of substituted thiourea in the prior art.
The invention provides a clean production method for substituted thiourea, which comprises the following steps:
s1, adding materials: adding organic amine into a reaction kettle by a first feeding tank, adding an ammonium thiocyanate solution into the reaction kettle by a second feeding tank, adding a sulfuric acid solution into the reaction kettle by a third feeding tank, and uniformly mixing to obtain a to-be-reacted liquid A;
s2, reaction: stirring the solution A to be reacted, gradually heating the solution A to 85-90 ℃ for reaction, and stopping the reaction when the mass content of the organic amine in the solution A is less than or equal to 0.5% to obtain a reaction solution B;
s3, centrifugation: cooling the reaction liquid B to 35-45 ℃, and then carrying out centrifugal separation to obtain a filtrate C and a filter cake D;
s4, preparing substituted thiourea: washing the filter cake D to obtain a washing liquid F, drying the filter cake D to obtain substituted thiourea, and recovering the evaporated moisture to the washing liquid F;
s5, treating filtrate C: adding ammonia water into the filtrate C, standing and separating to obtain an oil phase G and a water phase H, and allowing the oil phase G to enter the first feeding pool;
s6, concentration of ammonium sulfate solution: evaporating and concentrating the water phase H to obtain a concentrated water phase I, recovering evaporated water to a washing solution F, cooling the water phase I to 50 ℃, performing centrifugal separation to obtain ammonium sulfate and a mother solution J, and allowing the ammonium sulfate to enter a first storage room;
s7, extraction of ammonium sulfate: evaporating and concentrating the mother liquor J to obtain a concentrated water phase K, recovering evaporated water to a washing solution F, cooling the water phase K to 40 ℃, performing centrifugal separation to obtain ammonium sulfate and a mother liquor L, and allowing the ammonium sulfate to enter a first storage room;
s8, extracting ammonium thiocyanate: evaporating and concentrating the mother liquor L to obtain a concentrated water phase M, recovering evaporated water to a washing solution F, centrifugally separating the water phase M to obtain ammonium thiocyanate and a mother liquor N, and allowing the ammonium thiocyanate to enter a second storage room;
s9, recovering mother liquor N: adding the mother liquor N into the washing liquid F;
s10, recovering washing liquid F: feeding the washing liquid F into a second feeding pool;
s11, when the concentration of the ammonium thiocyanate solution in the second feeding tank is smaller than a set threshold value, adding ammonium thiocyanate into the second feeding tank from a second storage room or a raw material;
and S12, when the concentration of the ammonium thiocyanate solution in the second feeding tank is greater than a set threshold value, the second feeding tank is supplemented with deionized water.
When organic amine, ammonium thiocyanate and sulfuric acid are adopted to react to generate substituted thiourea, the generated industrial wastewater mainly contains unreacted organic amine, residual products, ammonium thiocyanate, free sulfuric acid and ammonium sulfate. Neutralizing with ammonia water and separating out organic phase, wherein the organic phase mainly contains unreacted organic amine and residual product, and the organic amine solution can be used for producing substituted thiourea again; the aqueous phase only contains two components of ammonium sulfate and ammonium thiocyanate, is easy to separate and recover, ammonium thiocyanate crystals can be obtained through evaporation and concentration, the content of ammonium thiocyanate in mother liquor can reach 40-65%, the ammonium sulfate only accounts for 3-8%, and the ammonium thiocyanate solution can be used for producing substituted thiourea.
According to the clean production method for replacing thiourea, as a preferred mode, when the sulfuric acid solution is added in the step S1, the temperature is less than or equal to 50 ℃, the time is 1.5-2h, and the temperature is kept for 1-1.5h after the addition.
In the clean production method for substituted thiourea, step S2 preferably includes the following three steps:
s21, heating to 60-65 ℃, and keeping the temperature for 0.5-4 h;
s22, heating to 75-80 ℃, and preserving heat for 1-4 h;
s23, heating to 85-90 ℃, and preserving heat for 2-6 h.
According to the clean production method for the substituted thiourea, ammonia water is added to adjust the pH value of the filtrate C to be 4.5-6.5 in a preferable mode in step S5, and the standing time is 2-4 h.
The invention relates to a clean production system for replacing thiourea, which comprises a reaction kettle, a first feeding pool, a second feeding pool and a third feeding pool which are connected with an inlet of the reaction kettle, a first concentration device and a first centrifugal device which are connected with an outlet of the reaction kettle, a washing device which is connected with the first centrifugal device, a second concentration device which is connected with the first concentration device, a second centrifugal device which is connected with the second concentration device, a first storage room and a second storage room which are connected with the second concentration device, wherein the first feeding pool, the second feeding pool and the third feeding pool are connected with an inlet of the reaction kettle; the second storage room is connected with the second feeding pool.
According to the clean production system for replacing thiourea, as a preferable mode, a concentration detection device for detecting the concentration of the ammonium thiocyanate solution is arranged in the second feeding pool.
The clean production system for the substituted thiourea, provided by the invention, preferably further comprises a third storage room which is connected with the washing device and is used for storing the substituted thiourea.
The clean production system for replacing thiourea, disclosed by the invention, further comprises a liquid storage tank which is connected with the second feeding tank, the first concentrating device, the first centrifugal device, the second concentrating device and the second centrifugal device respectively and is used for storing washing liquid F as a preferable mode.
The clean production system for replacing thiourea, provided by the invention, preferably further comprises a water inlet pipe connected with the second feeding tank.
The invention has the beneficial effects that:
(1) the cyclic utilization of resources is realized by the efficient reaction of the organic amine solution, the ammonium thiocyanate solution and the sulfuric acid solution and the ingenious design of the experimental process.
(2) Ammonia water is adopted for neutralization, so that organic matters are separated out and float out of the liquid level, and the separation and recovery are easy. The liquid after operation only contains two components of ammonium sulfate and ammonium thiocyanate, and is easy to separate and recover.
(3) According to the thermodynamic property of the mixed liquor of ammonium thiocyanate and ammonium sulfate, adopting evaporation concentration, under the proper condition separating out ammonium sulfate by-product, its nitrogen content is greater than 20.5%, and can be sold.
(4) The water resource is recycled and used as process water, so that the taking of water is reduced, the production wastewater replacing thiourea is thoroughly solved, and zero emission is realized.
(5) Through setting up the concentration detection device in the reinforced pond of second can the concentration of the interior ammonium thiocyanate solution of real-time supervision second to through control liquid storage tank, second storage room, the adjustment of inlet tube to the interior ammonium thiocyanate solution concentration of reinforced pond of second, improve the efficiency and the stability of reaction.
Drawings
FIG. 1 is a flow diagram of a clean production process for the replacement of thiourea;
FIG. 2 is a schematic diagram of a clean production system for the replacement of thiourea.
Reference numerals:
1. a reaction kettle; 2. a first feeding tank; 3. a second feeding tank; 4. a third feeding tank; 5. a first concentration device; 6. a first centrifugal device; 7. a washing device; 8. a second concentration device; 9. a second centrifugal device; 10. a first storage room; 11. a second storage room; 12. a concentration detection device; 13. a third storage room; 14. a liquid storage tank; 15. and (4) a water inlet pipe.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments.
Example 1
As shown in fig. 1, a clean production method for replacing thiourea comprises the following steps:
s1, adding materials: adding organic amine into a reaction kettle 1 by a first feeding tank 2, adding an ammonium thiocyanate solution into the reaction kettle 1 by a second feeding tank 3, adding a sulfuric acid solution into the reaction kettle 1 by a third feeding tank 4, keeping the temperature at 50 ℃ or lower for 1.5-2h when the sulfuric acid solution is added, preserving the heat for 1-1.5h after the addition is finished, and uniformly mixing to obtain a reaction solution A to be reacted;
s2, reaction: stirring the solution A to be reacted, gradually heating to 85-90 ℃ for reaction, wherein the gradual heating comprises the following three steps:
s21, heating to 60-65 ℃, and keeping the temperature for 0.5-4 h;
s22, heating to 75-80 ℃, and preserving heat for 1-4 h;
s23, heating to 85-90 ℃, and keeping the temperature for 2-6 h;
stopping the reaction when the mass content of the organic amine in the reaction liquid A is less than or equal to 0.5 percent to obtain reaction liquid B;
s3, centrifugation: cooling the reaction liquid B to 35-45 ℃, and then carrying out centrifugal separation to obtain a filtrate C and a filter cake D;
s4, preparing substituted thiourea: washing the filter cake D to obtain a washing liquid F, drying the filter cake D to obtain substituted thiourea, and recovering the evaporated moisture to the washing liquid F;
s5, treating filtrate C: adding ammonia water into the filtrate C to adjust the pH value to 4.5-6.5, standing for 2-4H to obtain an oil phase G and a water phase H, and allowing the oil phase G to enter a first feeding pool 2;
s6, concentration of ammonium sulfate solution: evaporating and concentrating the water phase H to obtain a concentrated water phase I, recovering evaporated water to a washing solution F, cooling the water phase I to 50 ℃, performing centrifugal separation to obtain ammonium sulfate and a mother solution J, and enabling the ammonium sulfate to enter a first storage room 10;
s7, extraction of ammonium sulfate: evaporating and concentrating the mother liquor J to obtain a concentrated water phase K, recovering evaporated water to a washing solution F, cooling the water phase K to 40 ℃, performing centrifugal separation to obtain ammonium sulfate and a mother liquor L, and enabling the ammonium sulfate to enter a first storage room 10;
s8, extracting ammonium thiocyanate: evaporating and concentrating the mother liquor L to obtain a concentrated water phase M, recovering evaporated water to a washing solution F, centrifugally separating the water phase M to obtain ammonium thiocyanate and a mother liquor N, and allowing the ammonium thiocyanate to enter a second storage room 11;
s9, recovering mother liquor N: adding the mother liquor N into the washing liquid F;
s10, recovering washing liquid F: the washing liquid F enters a second feeding tank 3;
s11, when the concentration of the ammonium thiocyanate solution in the second feeding tank 3 is smaller than a set threshold value, adding ammonium thiocyanate into the second feeding tank 3 from the second storage room 10 or the raw material;
and S12, when the concentration of the ammonium thiocyanate solution in the second feeding tank 3 is greater than a set threshold, the second feeding tank 3 is replenished with deionized water.
As shown in figure 2, the clean production system for replacing thiourea comprises a reaction kettle 1, a first feeding tank 2, a second feeding tank 3 and a third feeding tank 4 which are connected with the inlet of the reaction kettle 1, a first concentration device 5 and a first centrifugal device 6 which are connected with the outlet of the reaction kettle 1, a washing device 7 which is connected with the first centrifugal device 6, a second concentration device 8 connected to the first concentration device 5, a second centrifugation device 9 connected to the second concentration device 8, a first storage room 10 connected with the second concentration device 8, a second storage room 11, a third storage room 13 connected with the washing device 7 and used for storing substituted thiourea, a liquid storage tank 14 for storing the washing liquid F and a water inlet pipe 15 connected with the second feeding tank are respectively connected with the second feeding tank 3, the first concentrating device 5, the first centrifugal device 6, the second concentrating device 8 and the second centrifugal device 9; the second storage room 11 is connected with the second feeding tank 3, and a concentration detection device 12 for detecting the concentration of the ammonium thiocyanate solution is arranged in the second feeding tank 3.
The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art should be considered to be within the technical scope of the present invention, and the technical solutions and the inventive concepts thereof according to the present invention should be equivalent or changed within the scope of the present invention.
Claims (9)
1. A clean production method for replacing thiourea is characterized in that: the method comprises the following steps:
s1, adding materials: adding organic amine into a reaction kettle (1) by a first feeding tank (2), adding an ammonium thiocyanate solution into the reaction kettle (1) by a second feeding tank (3), adding a sulfuric acid solution into the reaction kettle (1) by a third feeding tank (4), and uniformly mixing to obtain a to-be-reacted liquid A;
s2, reaction: stirring the solution A to be reacted, gradually heating the solution A to 85-90 ℃ for reaction, and stopping the reaction when the mass content of the organic amine in the solution A to be reacted is less than or equal to 0.5% to obtain a reaction solution B;
s3, centrifugation: cooling the reaction liquid B to 35-45 ℃, and then carrying out centrifugal separation to obtain a filtrate C and a filter cake D;
s4, preparing substituted thiourea: washing the filter cake D to obtain a washing liquid F, drying the filter cake D to obtain substituted thiourea, and recovering the evaporated moisture to the washing liquid F;
s5, treating filtrate C: adding ammonia water into the filtrate C, standing and separating to obtain an oil phase G and a water phase H, and enabling the oil phase G to enter the first feeding pool;
s6, concentration of ammonium sulfate solution: evaporating and concentrating the water phase H to obtain a concentrated water phase I, recovering evaporated water to the washing liquid F, cooling the water phase I to 50 ℃, and performing centrifugal separation to obtain ammonium sulfate and a mother liquid J, wherein the ammonium sulfate enters a first storage room (10);
s7, extraction of ammonium sulfate: evaporating and concentrating the mother liquor J to obtain a concentrated water phase K, recovering evaporated water to the washing liquid F, cooling the water phase K to 40 ℃, and performing centrifugal separation to obtain ammonium sulfate and a mother liquor L, wherein the ammonium sulfate enters the first storage room (10);
s8, extracting ammonium thiocyanate: evaporating and concentrating the mother liquor L to obtain a concentrated water phase M, recovering evaporated water to the washing liquid F, centrifugally separating the water phase M to obtain ammonium thiocyanate and mother liquor N, and allowing the ammonium thiocyanate to enter a second storage room (11);
s9, recovering mother liquor N: adding the mother liquor N to the washing solution F;
s10, recovering washing liquid F: feeding the washing liquid F into the second feeding tank (3);
s11, when the concentration of the ammonium thiocyanate solution in the second feeding pool (3) is smaller than a set threshold value, adding the ammonium thiocyanate from the second storage room (11) or a raw material to the second feeding pool (3);
s12, when the concentration of the ammonium thiocyanate solution in the second feeding tank (3) is larger than a set threshold value, the second feeding tank (3) is replenished with deionized water.
2. A clean production process for substituted thioureas according to claim 1 characterized in that:
in step S1, the temperature is less than or equal to 50 ℃ when the sulfuric acid solution is added, the time is 1.5-2h, and the temperature is kept for 1-1.5h after the addition.
3. A clean production process for substituted thioureas according to claim 1 characterized in that:
in step S2, the stepwise temperature increase includes the following three steps:
s21, heating to 60-65 ℃, and keeping the temperature for 0.5-4 h;
s22, heating to 75-80 ℃, and preserving heat for 1-4 h;
s23, heating to 85-90 ℃, and preserving heat for 2-6 h.
4. A clean production process for substituted thioureas according to claim 1 characterized in that:
in step S5, adding ammonia water to adjust the pH value of the filtrate C to 4.5-6.5, and standing for 2-4 h.
5. A clean production system for substituted thiourea according to any one of claims 1 to 4, characterized in that: the device comprises a reaction kettle (1), a first feeding pool (2), a second feeding pool (3) and a third feeding pool (4) which are connected with an inlet of the reaction kettle (1), a first concentration device (5) and a first centrifugal device (6) which are connected with an outlet of the reaction kettle (1), a washing device (7) which is connected with the first centrifugal device (6), a second concentration device (8) which is connected with the first concentration device (5), a second centrifugal device (9) which is connected with the second concentration device (8), a first storage room (10) and a second storage room (11) which are connected with the second concentration device (8); the second storage room (11) is connected with the second feeding pool (3).
6. A clean production system for substituted thioureas according to claim 5 characterized in that: and a concentration detection device (12) for detecting the concentration of the ammonium thiocyanate solution is arranged in the second feeding tank (3).
7. A clean production system for substituted thioureas according to claim 5 characterized in that: and a third storage compartment (13) connected to the washing device (7) for storing the substituted thiourea.
8. A clean production system for substituted thioureas according to claim 5 characterized in that: and the washing machine also comprises a liquid storage tank (14) which is respectively connected with the second feeding tank (3), the first concentrating device (5), the first centrifugal device (6), the second concentrating device (8) and the second centrifugal device (9) and is used for storing the washing liquid F.
9. A clean production system for substituted thioureas according to claim 5 characterized in that: and the device also comprises a water inlet pipe (15) connected with the second feeding tank (3).
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