CN112979556A

CN112979556A - Clean production method of hydantoin and device for implementing method

Info

Publication number: CN112979556A
Application number: CN202110232858.0A
Authority: CN
Inventors: 李显扬; 应国海; 耿海涛
Original assignee: Bozun Investment Group Co Ltd
Current assignee: Bozun Investment Group Co Ltd
Priority date: 2021-03-03
Filing date: 2021-03-03
Publication date: 2021-06-18

Abstract

The invention discloses a clean production method of hydantoin and a device for implementing the method, wherein the method comprises the steps of taking hydroxyacetonitrile, ammonia or an ammonia release precursor compound, carbon dioxide or a carbon dioxide release precursor compound and water as raw materials, carrying out an ammonia carbonylation reaction by controlling a liquid level, and carrying out a cyclization reaction by using solid acid, thereby obtaining the hydantoin. The method and the device not only can save the production equipment investment of the hydantoin and reduce the production cost, but also have the advantages of no three wastes in the whole production process, environmental protection, cleanness, high yield, no byproducts and the like, overcome the defects of low yield and more three wastes in the existing hydantoin production method, and avoid the byproduct sulfate which has low value and is difficult to treat when sulfuric acid is used.

Description

Clean production method of hydantoin and device for implementing method

Technical Field

The invention belongs to the field of chemical industry, and particularly relates to an environment-friendly and clean production method of hydantoin and a device for implementing the method.

Background

Hydantoin also called hydantoin has the chemical name of 2, 4-imidazoledione, is an important chemical intermediate, and derivatives thereof are widely applied to the fields of medicines, pesticides and the like. In recent years, the use of hydantoin derivatives for modifying resins has attracted considerable attention from the leather industry.

Currently, multiple synthetic routes have been reported for hydantoin, and the major routes can be divided into glyoxal-urea route, glycine-cyclization route and hydroxyacetonitrile route. The method for producing 1 ton of hydantoin mainly comprises the steps of consuming 1.08 tons of glycine, 0.6 tons of sodium hydroxide (folded in hundred) and 1.3 tons of urea, and discharging about 4 tons of salt-containing wastewater, wherein the discharged salt-containing wastewater not only contains ammonium sulfate and sodium sulfate but also contains a plurality of organic impurities, so that the COD (chemical oxygen demand) is higher, the wastewater is very difficult to treat, and the domestic manufacturers for producing hydantoin by adopting the process mainly comprise the northriver Shijiazhuang Donghua Jinlong chemical industry limited company.

Since the 80 s of the last century, the foreign research team improved the synthesis of hydantoin by the classical Bucherer-Berg's method, and the carbonyl compound and cyanide were replaced by hydroxyacetonitrile, and hydantoin was synthesized by a tank-type high-pressure method, such as that of Japan Pond show industry, which uses a high-pressure method to prepare hydantoin with a hydantoin yield of 75.3% (JP 3-193748), and that of Zhuneihuang et al, which uses a high-pressure method to improve the hydantoin yield to 83% (JP 3-223238). By the last 90 th century, the Ouyangqing Kai team of the Nanjing industry university in China began to research the technology for synthesizing hydantoin and derivatives thereof by the Bucherer-Berg's method (for example, Cuiyou, Tangkaihua, Ouyangping Kai, the improved Bucherer-Berg's method for synthesizing hydantoin, the university of Nanjing chemical industry, Proc. 2, 1995), the tank-type high-pressure method for synthesizing hydantoin and the atmospheric method for synthesizing hydantoin were successively reported, and great progress was made, with the highest hydantoin yield reaching 86.2%, which exceeds the level reported in the foreign literature in the same period (CN 200410042000.4).

A great deal of experimental research is carried out on the technical ideas of Yuan Qihua and Gong Wen photo teams (CN 201910370199.X) of Yangguan chemical research institute and Wu-Yilong teams (CN 201510199303.5 and CN 201510157748.7) of Chongqing purple light chemical company based on the direct hydantoin method for producing the hydantoin by coproducing the glycine, and a technical route that the hydantoin and the hydantoin derivatives are prepared by a Bucerer-Berg's synthesis route from the hydroxyacetonitrile, the ammonia source and the carbon source, and then the hydantoin is prepared by acid addition and cyclization or the glycine is prepared by hydrolysis is also reported. In recent years, similar reports (Yuan Qihua, Chun Wei, Gong Wen photo, etc., research on hydantoin synthesis by a constant pressure method, leather science and engineering in 2020, Vol.30, pages 45-49 and 66) have been made by Yuan Qinhua and Gong Wen photo teams from the Yangguan coal chemical research institute, and related patents (CN 201910370199.X) have been applied. However, the hydantoin produced by the hydroxyacetonitrile method in China at present has a small scale, and the capacity of only the Wuxi Meihua chemical company Limited and the Hubei Xitai chemical company Limited, which are the subsidiary companies thereof, is about thousand tons.

With the increasing environmental protection situation, a process route for realizing green, environmental protection and sustainable development has become a consensus of people. The technology for synthesizing hydantoin by the hydroxyacetonitrile method provides a thought for green production of hydantoin, and meanwhile, the raw materials are cheap and easy to obtain, so that the method has obvious technical advantages for improving the market competitiveness of hydantoin products. However, the present method of synthesizing hydantoin by using hydroxy acetonitrile mainly has the following technical problems: 1) due to the poor thermal stability of the raw material, the hydroxy acetonitrile is easy to decompose, polymerize and generate other byproducts when participating in the reaction under high temperature and high pressure, so that the yield of the glycine is reduced, and the byproducts are increased; 2) because ammonia and carbon dioxide in the system are excessive and have strong corrosion to pipe fittings under the high-temperature and high-pressure reaction condition, the glycine synthesized by the direct hydantoin method has special requirements on the material quality of a reactor and the like; 3) the sulfuric acid is used as an acidification ring closing reagent, so that a large amount of acid-containing waste liquid is inevitably generated, the environment is polluted, and the production cost of the hydantoin is increased due to the difficult recovery and circulation of the sulfuric acid; 4) the instability of the hydantoin yield, which also reveals the operational instability of the production plant, the discontinuity in relation to the hydantoin yield, is essentially not reported for reasons of instability. The inventors have noted that the level of the reaction liquid in the aminocarbonylation reactor has a significant effect on the reaction yield and the effective conversion of hydroxyacetonitrile.

Based on the above problems in the prior art, there is a need for a clean method for producing hydantoin and an apparatus for implementing the method, which can effectively solve the above problems exposed in the hydantoin production process.

Disclosure of Invention

In view of the above, through research, the present inventors provide a clean production method of hydantoin, in which solid acid is used to replace sulfuric acid for carrying out acidification ring closing reaction, and the liquid level of the mixed liquid of the aminocarbonylation reaction is controlled to be above 85%, so that the risk caused by over-high pressure of the reaction system in the process of preparing hydantoin by the traditional hydroxyacetonitrile method and the corrosion of a large amount of carbon dioxide and ammonia to equipment are effectively avoided, and the pollution of sulfuric acid waste liquid to the environment is avoided due to no use of sulfuric acid, so that the method of the present invention has the characteristics of environmental protection and cleanness, and meanwhile, the method has no by-product and the effective conversion rate of hydroxyacetonitrile is high.

Meanwhile, the inventor also finds that in the process of producing hydantoin, if zirconium materials exist in the reaction system, the hydrolysis of the generated hydantoin into compounds such as glycine is promoted, and the solid acid and the glycine form glycinate, so that the yield of hydantoin is low. In other words, when a zirconium material is present in the reaction system, although the conversion rate of hydroxyacetonitrile is high, it is not efficiently converted into hydantoin and its hydantoin acid or the like, resulting in a low hydantoin yield and thus the presence of glycine or the like in the recovered solid acid catalyst.

In one aspect, the invention provides a method for the clean production of hydantoin, comprising the steps of:

(1) taking hydroxyl acetonitrile, ammonia or an ammonia release precursor compound, carbon dioxide or a carbon dioxide release precursor compound and water as raw materials, and carrying out an ammonia carbonylation reaction under the condition that more than 85% of liquid level does not exist zirconium to prepare an ammonia carbonylation reaction liquid;

(2) removing unreacted ammonia and carbon dioxide from the ammonia carbonylation reaction liquid obtained in the step (1), then concentrating the obtained reaction liquid after degassing, carrying out cyclization reaction on the obtained concentrated liquid and solid acid, and separating the solid acid after the reaction is finished to obtain a hydantoin aqueous solution;

(3) and (3) decoloring the hydantoin aqueous solution obtained in the step (2), cooling the obtained decoloring solution, crystallizing, and separating to obtain hydantoin and a crystallization mother liquor.

In another aspect, the present invention provides an apparatus for carrying out the above method, wherein the apparatus comprises:

an aminocarbonylation reaction unit comprising an aminocarbonylation reactor, the aminocarbonylation reactor being free of zirconium;

a cyclization reaction unit which is connected to the aminocarbonylation reaction unit in a fluid communication manner and comprises a stripping tower, an evaporation concentration system, an acidification cyclization reaction kettle and a first solid-liquid separation device which are in fluid communication; and

a crystallization unit coupled in fluid communication to the cyclization reaction unit and comprising a decolorization kettle, a second solid-liquid separation device, and a crystallization kettle in fluid communication.

Advantageous effects

The method and the corresponding device of the invention not only can save the production equipment investment of the hydantoin and reduce the production cost, but also have the advantages of no three wastes in the whole production process, environmental protection, cleanness, high yield, no byproducts and the like, and overcome the defects of low yield, more three wastes and the like of the prior hydantoin production method.

By avoiding the use of sulfuric acid or the like, a sulfate which is low in value and difficult to handle is not by-produced.

The control of the liquid level of the reaction mixture in the aminocarbonylation reactor of the present invention is critical to the stability and high yield of hydantoin, and the present inventors have found that the present invention is advantageous for high conversion of hydroxyacetonitrile and increases the yield of hydantoin when the aminocarbonylation reaction is carried out at a liquid level of 85% or more.

The invention further improves the yield of the hydantoin by avoiding the use of zirconium materials in the system for producing the hydantoin.

The hydantoin technological operation adopting the method and the corresponding device can be a continuous, semi-continuous or intermittent operation mode, and has the characteristics of flexible and large operation, low production cost, high hydantoin yield and purity, simple production device, low equipment investment and the like.

Drawings

Fig. 1 is a schematic diagram of an exemplary apparatus for carrying out the hydantoin production process of the present invention.

Detailed Description

The invention will be described below with reference to exemplary embodiments, but the scope of protection of the invention is not limited thereto.

In the present invention, the term "liquid level" means, unless otherwise specified, the proportion of the total volume of the liquid medium in the reaction vessel to the volume of the reaction vessel. For example, in step (1) of the method of the present invention, the liquid level refers to a ratio (e.g., 85% to 95%) of the total volume of the mixed liquid of the raw materials (e.g., the mixed liquid of hydroxyacetonitrile, ammonia, carbon dioxide, and water) to the volume of the aminocarbonylation reactor.

In the present invention, unless otherwise indicated, the terms "ammonia-releasing precursor compound" and "carbon dioxide-releasing precursor compound" refer to any compound known in the art that is capable of releasing ammonia and carbon dioxide, respectively, under the various reaction conditions of the aminocarbonylation reaction of the present invention. Herein, the "ammonia-releasing precursor compound" and the "carbon dioxide-releasing precursor compound" may represent the same compound or different compounds, for example, both may be selected from ammonium bicarbonate, ammonium carbonate, or a mixture thereof.

In one embodiment, the invention relates to a method for the clean production of hydantoin, comprising the following steps:

(3) and (3) decoloring the hydantoin aqueous solution obtained in the step (2), cooling the obtained decoloring solution for crystallization, and separating to obtain hydantoin and a crystallization mother liquor.

In some preferred embodiments, in step (1), the molar ratio of the hydroxyacetonitrile to the ammonia or the ammonia-releasing precursor compound is 1 (3.5-4.3), the molar ratio of the ammonia or the ammonia-releasing precursor compound to the carbon dioxide or the carbon dioxide-releasing precursor compound is (1.3-1.4): 1, and the molar ratio of the ammonia or the ammonia-releasing precursor compound to the water is 1 (10-12), wherein the amounts of the ammonia-releasing precursor compound and the carbon dioxide-releasing precursor compound are calculated as ammonia and carbon dioxide, respectively.

In some preferred embodiments, in step (1), the aminocarbonylation reaction is carried out at a level of from 85% to 95% in the absence of zirconium.

In some preferred embodiments, in step (1), hydroxy acetonitrile, ammonia, carbon dioxide and water are used as the starting materials.

In some preferred embodiments, in step (1), the hydroxyacetonitrile is an aqueous solution of hydroxyacetonitrile having a mass percentage of 20 to 65 wt% (preferably 35 to 60 wt%, for example 40 to 50 wt%) and a pH of 2 to 4.

In some preferred embodiments, in step (1), ammonia or an ammonia releasing precursor compound, carbon dioxide or a carbon dioxide releasing precursor compound, and water are mixed to obtain an ammonium bicarbonate mixture before adding the hydroxyacetonitrile.

In some preferred embodiments, in step (1), the temperature of the aqueous hydroxyacetonitrile solution and the ammonium bicarbonate mixture is raised to 50 ℃ to 70 ℃ before mixing the two solutions.

In some preferred embodiments, in step (1), the step of aminocarbonylation is performed at 100 ℃ to 125 ℃ and under a pressure of 2.0 to 4.0MPa for 60 to 120 min.

In some preferred embodiments, in step (2), unreacted carbon dioxide and ammonia are removed from the aminocarbonylation reaction solution obtained in step (1) by stripping or under a negative pressure condition. Preferably, the residual amount of ammonia in the reaction solution after degassing is less than 50 ppm.

In a further preferred embodiment, the stripping treatment is carried out while controlling the bottom temperature of the stripping column to 100 ℃ to 110 ℃ and the top temperature to 98 ℃ to 100 ℃.

In a further preferred embodiment, the ammonia and carbon dioxide removed in step (2) are recycled to said step (1).

In some preferred embodiments, in the step (2), the reaction solution after degassing is subjected to a concentration treatment under reduced pressure. Preferably, the degassed reaction solution is concentrated to 15% to 40%, preferably 15% to 20% of its original volume.

In some preferred embodiments, in step (2), the charged mass of the solid acid is 2% to 10% of the mass of the concentrate.

In some preferred embodiments, in step (2), the solid acid is a polymer material subjected to sulfonation treatment, and sulfonated Silica (SiO)₂/SO₄) Or iron (Fe) oxide₂O₃/SO₄) One or more of. Preferably, the polymer material subjected to sulfonation treatment is a cation exchange resin subjected to sulfonation treatment, preferably a strongly acidic styrene cation exchange resin, such as a macroporous strongly acidic styrene cation exchange resin. The sulfonated silica is, for example, silica gel sulfonic acid. In this context, the solid acid can be reused by simple isolation.

In some preferred embodiments, in the step (2), the temperature of the cyclization reaction is 95-115 ℃ and the reaction time is 90-120 min.

In some preferred embodiments, in step (2), the solid acid is isolated by centrifugation or filtration.

In some preferred embodiments, in step (3), the aqueous hydantoin solution obtained in step (2) is decolorized by the addition of activated carbon.

In a further preferred embodiment, in step (3), the amount of the activated carbon added is 0.2% to 0.8% by mass of the hydantoin aqueous solution.

In some preferred embodiments, in the step (3), the temperature of the decolorization is 80 ℃ to 100 ℃, and the time of the decolorization is 50min to 90 min.

In some preferred embodiments, in step (3), the activated carbon is removed by separation by centrifugation or filtration to obtain the decolorized solution.

In some preferred embodiments, in step (3), the crystallization is performed by cooling the obtained decolorized solution to 0 ℃ to 30 ℃.

In some preferred embodiments, in step (3), the hydantoin and crystallization mother liquor are separated by centrifugation or filtration.

In some preferred embodiments, the crystallization mother liquor in step (3) is recycled to the step (2) to participate in the concentration process.

In some preferred embodiments, the clean production process of hydantoin according to the present invention comprises the following steps:

i) mixing ammonia or ammonia release precursor compound, carbon dioxide or carbon dioxide release precursor compound and water to obtain ammonium bicarbonate mixed solution with the temperature of 50-70 ℃, then adding hydroxyl acetonitrile aqueous solution with the temperature of 50-70 ℃ into the mixed solution, mixing, under the conditions of 100-125 ℃ of temperature and 2.0-4.0 MPa of pressure, the aminocarbonylation reaction is carried out for 60-120 min under the condition that 85-95 percent of liquid level does not exist zirconium to prepare the aminocarbonylation reaction liquid, wherein the molar ratio of the hydroxyacetonitrile to the ammonia or the ammonia-releasing precursor compound is 1: (3.5-4.3) the molar ratio of ammonia or ammonia-releasing precursor compound to carbon dioxide or carbon dioxide-releasing precursor compound is (1.3-1.4): 1, the molar ratio of ammonia or ammonia-releasing precursor compound to water is 1: (10-12) of a first step, wherein the ammonia-releasing precursor compound and the carbon dioxide-releasing precursor compound are present in amounts calculated as ammonia and carbon dioxide, respectively;

ii) carrying out steam stripping treatment on the ammonia carbonylation reaction liquid obtained in the step i), controlling the bottom temperature of a stripping tower to be 100-110 ℃ and the top temperature to be 98-100 ℃ so as to remove unreacted ammonia and carbon dioxide and obtain degassed reaction liquid with the ammonia residual quantity lower than 50ppm, and recycling the removed ammonia and carbon dioxide to the step i); concentrating the reaction solution after degassing to 15-40% of the original volume to obtain a concentrated solution; adding solid acid into the concentrated solution for cyclization reaction, wherein the feeding mass of the solid acid is 2-10% of the mass of the concentrated solution, the temperature of the cyclization reaction is 95-115 ℃, and the reaction time is 90-120 min, so as to obtain hydantoin aqueous solution containing the solid acid; carrying out solid-liquid separation on the hydantoin aqueous solution containing the solid acid to obtain the solid acid and the hydantoin aqueous solution;

iii) adding activated carbon accounting for 0.2-0.8% of the mass of the hydantoin aqueous solution, decoloring the hydantoin aqueous solution at 80-100 ℃ for 50-90 min, then removing the activated carbon through solid-liquid separation, cooling the obtained decoloring solution to 0-30 ℃ for crystallization, performing solid-liquid separation, drying the obtained solid to obtain hydantoin and crystallization mother liquor, and circulating the crystallization mother liquor to the step (ii) to participate in the concentration treatment.

In some preferred embodiments, the process is one or more of a batch, semi-continuous, or continuous process, preferably a semi-continuous or continuous process.

In one embodiment, the invention relates to an apparatus for carrying out the above method, wherein the apparatus comprises:

In some preferred embodiments, the aminocarbonylation reaction unit further comprises a preheater and a mixer, and the mixer is fluidly connected to the aminocarbonylation reactor, and the preheater is fluidly connected to the mixer.

In a further preferred embodiment, the mixer is a micron-sized reaction channel or an SV-type static mixer.

In some preferred embodiments, the evaporative concentration system is an MVR evaporative system.

In some preferred embodiments, the first solid-liquid separation device and the second solid-liquid separation device may be a centrifuge device, a filtration device, or the like.

In some preferred embodiments, the crystallization unit further comprises a third solid-liquid separation device and a drying system disposed in fluid communication downstream of the crystallization vessel. Preferably, the third solid-liquid separation device may be a centrifuge device, a filter device, or the like.

In some preferred embodiments, the material of the aminocarbonylation reactor is 316L.

In some preferred embodiments, the preheater, the aminocarbonylation reactor, the evaporation concentration system, the acidification cyclization reaction kettle, the decolorization kettle, the crystallization kettle and the drying system are respectively provided with a temperature regulation auxiliary device.

Next, with reference to the content of fig. 1, an exemplary aspect of the present invention is explained as follows, however, the scope of the present invention is not limited thereto:

the exemplary hydantoin apparatus for producing comprises a preheater, a static mixer, an ammonia carbonylation reactor, a stripping tower, an MVR evaporation system, an acidification cyclization reaction kettle, a separation device (I), a decolorization kettle, a separation device (II), a crystallization kettle, a separation device (III) and a drying system, wherein the preheater, the ammonia carbonylation reactor, the MVR evaporation system, the acidification cyclization reaction kettle, the decolorization kettle, the crystallization kettle and the drying system are respectively provided with a temperature regulation auxiliary device.

The method comprises the steps of enabling ammonium carbonate mixed liquor obtained by mixing ammonia, carbon dioxide and water to enter a preheater, enabling a hydroxyacetonitrile aqueous solution to enter another preheater, enabling the preheated ammonium carbonate mixed liquor and the hydroxyacetonitrile aqueous solution to enter a static mixer, enabling the mixed liquor and the hydroxyacetonitrile aqueous solution to enter an aminocarbonylation reactor (made of 316L for example) after mixing, and enabling the mixed liquor and the hydroxyacetonitrile aqueous solution to perform an aminocarbonylation reaction under the condition that zirconium does not exist at a liquid level of more than 85% to obtain an aminocarbonylation reaction liquid.

The ammonia carbonylation reaction liquid enters a stripping tower for steam stripping treatment to remove unreacted ammonia and carbon dioxide (the unreacted ammonia and the carbon dioxide can be recycled), the obtained reaction liquid after degassing enters an MVR evaporation system for concentration treatment, the obtained concentrated liquid enters an acidification cyclization reaction kettle, and solid acid is added into the acidification cyclization reaction kettle for cyclization reaction to obtain hydantoin aqueous solution containing the solid acid; carrying out solid-liquid separation on the hydantoin aqueous solution containing the solid acid by using a separation device (I) to obtain the solid acid (which can be recycled to the acidification cyclization reaction kettle) and the hydantoin aqueous solution; and (3) allowing the hydantoin aqueous solution to enter a decoloring kettle, adding activated carbon into the hydantoin aqueous solution for decoloring, removing the activated carbon through a separation device (II), allowing the obtained decoloring solution to enter a crystallization kettle for crystallization, separating hydantoin crystals from crystallization mother liquor (which can be recycled to an MVR evaporation system) through a separation device (III), and allowing the hydantoin crystals to enter a drying system for drying to obtain hydantoin.

The clean production process of the hydantoin may employ one or more of a batch, semi-continuous, or continuous operating method.

Exemplary aspects of the present invention may be illustrated by the following numbered paragraphs, but the scope of the present invention is not limited thereto:

1. a clean production method of hydantoin, which comprises the following steps:

2. The method of paragraph 1, wherein in step (1), the molar ratio of the hydroxyacetonitrile to the ammonia or ammonia-releasing precursor compound is 1 (3.5-4.3), the molar ratio of the ammonia or ammonia-releasing precursor compound to the carbon dioxide or carbon dioxide-releasing precursor compound is 1.3-1.4): 1, and the molar ratio of the ammonia or ammonia-releasing precursor compound to water is 1 (10-12), wherein the amounts of the ammonia-releasing precursor compound and the carbon dioxide-releasing precursor compound are calculated as ammonia and carbon dioxide, respectively.

3. The method of paragraph 1 or 2, wherein in step (1), the aminocarbonylation reaction is carried out at a level of 85% to 95% in the absence of zirconium.

4. The process of any of paragraphs 1-3, wherein in step (1) hydroxyacetonitrile, ammonia, carbon dioxide and water are the starting materials.

5. The method according to any one of paragraphs 1-4, wherein in step (1), the hydroxyacetonitrile is an aqueous hydroxyacetonitrile solution with a pH of 2-4 and a mass percent of 20-65 wt%.

6. The method of any of paragraphs 1-5, wherein in step (1), the ammonia or ammonia releasing precursor compound, carbon dioxide or carbon dioxide releasing precursor compound, and water are mixed to obtain an ammonium bicarbonate mixture prior to adding the hydroxyacetonitrile.

7. The method according to paragraph 6, wherein in step (1), the temperature of the aqueous hydroxyacetonitrile solution and the ammonium carbonate mixture is raised to 50 ℃ to 70 ℃ before mixing the two solutions.

8. The method according to any one of paragraphs 1 to 7, wherein in step (1), the aminocarbonylation is carried out at a temperature of 100 to 125 ℃ and a pressure of 2.0 to 4.0MPa for 60 to 120 min.

9. The method according to any one of paragraphs 1 to 8, wherein in step (2), unreacted carbon dioxide and ammonia are removed from the aminocarbonylation reaction liquid obtained in step (1) by stripping or under a negative pressure condition.

10. The method of any of paragraphs 1-9, wherein the residual amount of ammonia in the degassed reaction solution is less than 50 ppm.

11. The method according to any one of paragraphs 1 to 10, wherein the stripping treatment is performed while controlling a bottom temperature of the stripping column to 100 ℃ to 110 ℃ and a top temperature to 98 ℃ to 100 ℃.

12. The method of any of paragraphs 1-11, wherein the ammonia and carbon dioxide removed in step (2) are recycled to step (1).

13. The method according to any one of paragraphs 1 to 12, wherein in step (2), the reaction solution after degassing is subjected to a concentration treatment under reduced pressure.

14. The method of any of paragraphs 1-13, wherein the degassed reaction solution is concentrated to 15-40% of its original volume.

15. The method of any of paragraphs 1-14, wherein in step (2), the charged mass of the solid acid is 2-10% of the mass of the concentrate.

16. The method of any of paragraphs 1-15, wherein, in step (2), the solid acid is one or more of a sulfonated polymeric material, sulfonated silica, or sulfonated ferric oxide.

17. The method of paragraph 16, wherein the sulfonated polymeric material is a cation exchange resin that has been sulfonated.

18. The method of paragraph 16 wherein the sulfonated silica is silica gel sulfonic acid.

19. The method of any of paragraphs 1-18, wherein in step (2), the temperature of the cyclization reaction is 95-115 ℃ and the reaction time is 90-120 min.

20. The method of any of paragraphs 1-19, wherein, in step (2), the solid acid is isolated by centrifugation or filtration.

21. The process according to any of paragraphs 1-20, wherein in step (3) the aqueous hydantoin solution obtained in step (2) is subjected to said decolorizing by adding activated carbon.

22. The method according to paragraph 21, wherein in step (3), the amount of activated carbon added is 0.2% to 0.8% by mass of the aqueous hydantoin solution.

23. The method according to any one of paragraphs 1 to 22, wherein, in step (3), the temperature of the decolorization is 80 ℃ to 100 ℃, and the time of the decolorization is 50min to 90 min.

24. The method of any of paragraphs 21-23, wherein in step (3), the activated carbon is removed by centrifugation or filtration to obtain the decolorized solution.

25. The method according to any one of paragraphs 1 to 24, wherein, in step (3), the obtained decolorized solution is cooled to 0 ℃ to 30 ℃ for the crystallization.

26. The process of any of paragraphs 1-25, wherein in step (3) the hydantoin and crystallization mother liquor are separated by centrifugation or filtration.

27. The method of any of paragraphs 1-26, wherein the crystallization mother liquor in step (3) is recycled to step (2) to participate in the concentration process.

28. The method according to any of paragraphs 1-27, wherein the clean production process of hydantoin comprises the steps of:

i) mixing the ammonia or the ammonia release precursor compound, the carbon dioxide or the carbon dioxide release precursor compound and water to obtain ammonium bicarbonate mixed solution with the temperature of 50-70 ℃, then adding hydroxyl acetonitrile water solution with the temperature of 50-70 ℃ into the mixed solution, mixing the mixture, under the conditions of 100-125 ℃ of temperature and 2.0-4.0 MPa of pressure, the aminocarbonylation reaction is carried out for 60-120 min under the condition that 85-95 percent of liquid level does not exist zirconium to prepare the aminocarbonylation reaction liquid, wherein the molar ratio of the hydroxyacetonitrile to the ammonia or ammonia releasing precursor compound is 1: (3.5 to 4.3), the molar ratio of ammonia or ammonia-releasing precursor compound to carbon dioxide or carbon dioxide-releasing precursor compound is (1.3-1.4): 1, the molar ratio of ammonia or ammonia-releasing precursor compound to water being 1: (10-12) of a first step, wherein the ammonia-releasing precursor compound and the carbon dioxide-releasing precursor compound are present in amounts calculated as ammonia and carbon dioxide, respectively;

29. The method of any of paragraphs 1-28, wherein the method is one or more of a batch, semi-continuous or continuous operation method.

30. An apparatus for implementing the method of any of paragraphs 1-29, wherein the apparatus comprises:

31. The apparatus of paragraph 30, wherein the aminocarbonylation reaction unit further comprises a preheater and a mixer, and the mixer is fluidly connected to the aminocarbonylation reactor, and the preheater is fluidly connected to the mixer.

32. The apparatus of paragraph 31, wherein the mixer is a micron-sized reaction channel or an SV-type static mixer.

33. The apparatus of any of paragraphs 30-32, wherein the evaporative concentration system is an MVR evaporation system.

34. The apparatus of any of paragraphs 30-33, wherein the first solid-liquid separation device and the second solid-liquid separation device are centrifugal devices or filtration devices.

35. The apparatus of any of paragraphs 30-34, wherein the crystallization unit further comprises a third solid-liquid separation device and a drying system disposed in fluid communication downstream of the crystallization vessel.

36. The apparatus of paragraph 35, wherein the third solid liquid separation device is a centrifuge or a filtration device.

37. The apparatus of any of paragraphs 30-36, wherein the material of the aminocarbonylation reactor is 316L.

38. The apparatus of any of paragraphs 30-37, wherein the preheater, the aminocarbonylation reactor, the evaporative concentration system, the acidification cyclization reaction kettle, the decolorization kettle, the crystallization kettle, and the drying system are respectively provided with a temperature regulation auxiliary apparatus.

Examples

Hereinafter, preferred embodiments of the present invention will be described in detail. The experimental procedures, which are not specifically shown in the examples, are generally performed under conventional conditions, and the examples are given for better illustration of the present invention, but the present invention is not limited to the examples. Therefore, those skilled in the art can make various modifications and adaptations to the embodiments based on the above disclosure, and still fall within the scope of the invention.

Unless otherwise indicated, each of the reagents, materials and devices employed in the following examples and comparative examples are commercially available reagents, materials and devices known in the art. Unless otherwise indicated, the various operations hereinafter are conventional operations known in the art, as may be found, for example, in the following descriptions: wangzkui et al, "principles of chemical industry (fifth edition), chemical industry publishers, 1 month in 2018; yellow portrait, et al, "general theory of fine chemical industry (second edition), chemical industry publishers, 3 months 2015; chang et al, Fine chemical engineering principles and technology, Sichuan scientific and technical Press, 10 months in 2005.

The liquid chromatography analyses in the following examples and comparative examples employed an agilent-2000 high performance liquid chromatograph, C18 column; taking methanol/water as a mobile phase at a ratio of 30: 70; the elution conditions were: 1mL/min, column temperature 25 ℃.

Example 1

2364 g of deionized water is added into a 4000ml pressure-resistant aminocarbonylation reactor (material is 316L) with a feeding and stirring device, 216.5 g of ammonia gas and 420.4 g of carbon dioxide gas are introduced, the feeding molar ratio of the ammonia gas to the carbon dioxide is controlled to be 1.333:1, the feeding molar ratio of the ammonia to the water is controlled to be 1:10.313, and then the temperature is raised to 70 ℃ to obtain an ammonium bicarbonate mixed solution. 453.8 g (3.185mol) of an aqueous hydroxyacetonitrile solution at 70 ℃ having a pH of 3.0 and 40 wt% were added thereto at a uniform rate of 50g/min so that the molar feed ratio of ammonia to hydroxyacetonitrile was 4.0:1 and the feed time of the aqueous hydroxyacetonitrile solution was 9.1 min. During the course of adding the aqueous hydroxyacetonitrile solution, the temperature in the aminocarbonylation reactor was raised to 100 ℃, after the addition of the aqueous hydroxyacetonitrile solution was completed, the temperature was immediately raised to 110 ℃, and the reaction was stirred for 60 minutes under a pressure of 2.0MPa, wherein the volume of the reaction mixture was 85% of the volume of the aminocarbonylation reactor (i.e., the liquid level was 85%). After the reaction, the reaction mixture was cooled to 80 ℃ and depressurized to normal pressure to obtain 3452.8 g of the aminocarbonylation reaction solution.

The obtained aminocarbonylation reaction solution was subjected to stripping in a stripping column (bottom temperature 110 ℃ C., top temperature 100 ℃ C.) so that the residual amount of ammonia in the degassed reaction solution obtained by stripping was less than 50ppm, thereby obtaining 2930.6 g of a degassed reaction solution. The obtained reaction solution after degassing is concentrated under reduced pressure (-0.09MPa) by adopting an MVR evaporation system to obtain 586.12 g of concentrated solution, wherein the concentrated solution is concentrated to 20% of the original volume. And transferring the concentrated solution into an acidification cyclization reaction kettle, adding 58.61 g of silica gel sulfonic acid into the concentrated solution, heating to 100 ℃, reacting for 120min, and filtering solid acid after the reaction is finished to obtain a hydantoin aqueous solution.

585.1 g of hydantoin aqueous solution transferred to a decoloring kettle is added with 4.68 g of activated carbon, decoloring treatment is carried out for 90min at 100 ℃, the activated carbon is removed by filtration, and light yellow filtrate 584.5 g is obtained, wherein the mass percentage of the hydantoin is 53.4 wt%, and the hydantoin yield is 98% (calculated by hydroxyl acetonitrile) by liquid chromatography. Transferring the filtrate into a crystallization kettle, cooling to 10 ℃, separating out a large amount of white precipitate, filtering and separating the white precipitate, drying to obtain 283.75 g of white hydantoin with the purity of 99.0 percent and the single extraction rate of the hydantoin of 90 percent, wherein the weight of the crystallization mother liquor obtained by filtering is 290.75 g, and the mass percentage of the hydantoin in the crystallization mother liquor is 9.75 percent by weight by liquid chromatography analysis. The recovered silica gel sulfonic acid after filtration is washed by a small amount of water and then directly recycled to the next acidification and cyclization reaction, the weight of the recovered silica gel sulfonic acid is 58.11 g after drying, and the recovery rate of the solid acid catalyst is 99.15%.

Example 2

2364 g of deionized water is added into a 4000ml pressure-resistant aminocarbonylation reactor (material is 316L) with a feeding and stirring device, 216.5 g of ammonia gas and 420.4 g of carbon dioxide gas are introduced, the feeding molar ratio of the ammonia gas to the carbon dioxide is controlled to be 1.333:1, the feeding molar ratio of the ammonia to the water is controlled to be 1:10.313, and then the temperature is raised to 70 ℃ to obtain an ammonium bicarbonate mixed solution. 453.8 g (3.185mol) of a 40 wt% aqueous solution of hydroxyacetonitrile at 50 ℃ having a pH of 3.0 was added thereto at a constant rate of 50g/min so that the molar ratio of ammonia to hydroxyacetonitrile fed was 4.0:1 and the time of addition of the aqueous solution of hydroxyacetonitrile was 9.1 min. During the course of adding the aqueous hydroxyacetonitrile solution, the temperature in the aminocarbonylation reactor was raised to 100 ℃, and after the addition of the aqueous hydroxyacetonitrile solution was completed, the temperature was immediately raised to 125 ℃, and the reaction was stirred for 90min under a pressure of 3.8MPa, wherein the volume of the reaction mixture was 86% of the volume of the aminocarbonylation reactor (i.e., the liquid level was 86%). After the reaction, the reaction mixture was cooled to 80 ℃ and depressurized to normal pressure to obtain 3452.8 g of the aminocarbonylation reaction solution.

The obtained aminocarbonylation reaction solution was subjected to stripping in a stripping column (bottom temperature 105 ℃ C., top temperature 98 ℃ C.) so that the residual amount of ammonia in the degassed reaction solution obtained by stripping was less than 50ppm, thereby obtaining 2830.0 g of a degassed reaction solution. The obtained reaction solution after degassing is concentrated under reduced pressure (-0.092MPa) by adopting an MVR evaporation system to 18 percent of the original volume, so that 509.40 g of concentrated solution is obtained. Transferring the concentrated solution into an acidification cyclization reaction kettle, adding 15.28 g of the silica gel sulfonic acid recovered in the example 1 into the concentrated solution, heating to 95 ℃, reacting for 120min, and filtering solid acid after the reaction is finished to obtain a hydantoin aqueous solution.

509.5 g of hydantoin aqueous solution transferred into a decoloring kettle is added with 1.02 g of activated carbon, decoloring treatment is carried out for 60min at the temperature of 90 ℃, the activated carbon is removed by filtration, and light yellow filtrate 508.9 g is obtained, wherein the mass percentage of the hydantoin is 61.95 wt%, and the yield of the hydantoin is 99% (calculated by hydroxy acetonitrile). Transferring the filtrate into a crystallization kettle, cooling to 0 ℃, separating out a large amount of white precipitate, filtering and separating the white precipitate, drying to obtain 302.53 g of white hydantoin with the purity of 99.0 percent and the single extraction rate of the hydantoin of 98 percent, wherein the weight of crystallization mother liquor obtained by filtering is 194.71 g, and the mass percentage of the hydantoin in the crystallization mother liquor is 8.03wt percent by liquid chromatography analysis. The recovered silica gel sulfonic acid after filtration is washed by a small amount of water and then directly recycled to the next acidification and cyclization reaction, the weight of the recovered silica gel sulfonic acid is 15.13 g after drying, and the recovery rate of the solid acid catalyst is 99.0%.

Example 3

2698.5 g of deionized water is added into a 4000ml pressure-resistant ammonia carbonylation reactor (material is 316L) with a feeding and stirring device, 240.4 g of ammonia gas and 444.4 g of carbon dioxide gas are introduced, the feeding molar ratio of the ammonia gas to the carbon dioxide is controlled to be 1.40:1, the feeding molar ratio of the ammonia to the water is controlled to be 1:10.601, and then the temperature is raised to 70 ℃ to obtain ammonium bicarbonate mixed solution. 399.0 g (3.50mol) of an aqueous hydroxyacetonitrile solution at a temperature of 70 ℃ and 50 wt% and a pH of 3.2 were added thereto at a constant rate of 100g/min so that the molar feed ratio of ammonia to hydroxyacetonitrile was 4.0:1 and the feed time of the aqueous hydroxyacetonitrile solution was 9.1min, and during the addition of the aqueous hydroxyacetonitrile solution, the temperature in the aminocarbonylation reactor was raised to 100 ℃ and immediately after the addition of the aqueous hydroxyacetonitrile solution, the temperature was raised to 125 ℃ and the reaction was stirred for 90min under a pressure of 4.0MPa, wherein the volume of the reaction mixture was 92% of the volume of the aminocarbonylation reactor (i.e., the liquid level was 92%). After the reaction, the reaction mixture was cooled to 85 ℃ and depressurized to normal pressure, whereby 3782.3 g of the aminocarbonylation reaction solution was obtained.

The obtained aminocarbonylation reaction solution was subjected to stripping in a stripping column (bottom temperature 100 ℃ C., top temperature 98 ℃ C.) so that the residual amount of ammonia in the degassed reaction solution obtained by stripping was less than 50ppm, thereby obtaining 3211.0 g of a degassed reaction solution. The obtained reaction solution after degassing is concentrated under reduced pressure (-0.085MPa) by adopting an MVR evaporation system to obtain 481.65 g of concentrated solution, wherein the concentration is 15% of the original volume. Transferring the concentrated solution into an acidification cyclization reaction kettle, adding 15.13 g of the silica gel sulfonic acid recovered in the example 2 into the concentrated solution, heating to 110 ℃, reacting for 90min, and filtering solid acid after the reaction is finished to obtain a hydantoin aqueous solution.

481.2 g of hydantoin aqueous solution transferred into a decoloring kettle is added with 1.4 g of activated carbon, decoloring treatment is carried out for 50min at the temperature of 80 ℃, the activated carbon is removed by filtration, and light yellow filtrate 480.9 g is obtained, wherein the mass percentage of the hydantoin is 72.42 wt%, and the hydantoin yield is 99.5% (calculated by hydroxyl acetonitrile) by liquid chromatography analysis. Transferring the filtrate into a crystallization kettle, cooling to 10 ℃, separating out a large amount of white precipitate, filtering and separating the white precipitate, drying to obtain 342.93 g of white hydantoin with the purity of 99.0 percent and the single extraction rate of the hydantoin of 97 percent, wherein the weight of the crystallization mother liquor obtained by filtering is 130.97 g, and the mass percentage of the hydantoin in the crystallization mother liquor is 6.08wt percent by liquid chromatography analysis. The recovered silica gel sulfonic acid after filtration is washed by a small amount of water and then directly recycled to the next acidification and cyclization reaction, the weight of the recovered silica gel sulfonic acid is 15.13 g after drying, and the recovery rate of the solid acid catalyst is 100%. The mother liquor of the hydantoin crystallization is recycled to the next step of the condensation treatment of the degassed reaction solution.

Example 4

2775.6 g of deionized water is added into a 4000ml pressure-resistant aminocarbonylation reactor (material is 316L) with a feeding and stirring device, 247.3 g of ammonia gas and 452.6 g of carbon dioxide gas are introduced, the feeding molar ratio of the ammonia gas to the carbon dioxide is controlled to be 1.40:1, the feeding molar ratio of the ammonia to the water is controlled to be 1:10.60, and then the temperature is raised to 70 ℃ to obtain ammonium bicarbonate mixed solution. 410.4 g (3.60mol) of a 70 ℃ aqueous hydroxyacetonitrile solution containing 50 wt% of ammonia and having a pH of 2.5 was fed thereto at a constant rate of 100g/min so that the molar feed ratio of ammonia to hydroxyacetonitrile was 4.0:1 and the feed time of the aqueous hydroxyacetonitrile solution was 9.1min, and during the addition of the aqueous hydroxyacetonitrile solution, the temperature in the aminocarbonylation reactor was raised to 100 ℃ and immediately after the addition of the aqueous hydroxyacetonitrile solution, the temperature was raised to 120 ℃ and the reaction was stirred for 120min under a pressure of 4.0MPa, wherein the volume of the reaction mixture was 95% of the volume of the aminocarbonylation reactor (i.e., the liquid level was 95%). After the reaction, the reaction mixture was cooled to 85 ℃ and depressurized to normal pressure, whereby 3885.9 g of the aminocarbonylation reaction solution was obtained.

The obtained aminocarbonylation reaction solution was subjected to stripping in a stripping column (bottom temperature 110 ℃ C., top temperature 100 ℃ C.) so that the residual amount of ammonia in the degassed reaction solution obtained by stripping was less than 50ppm, thereby obtaining 3000.0 g of a degassed reaction solution. The resulting degassed reaction solution and 130.97 g (hydantoin mass% of 7.98 wt%) of the hydantoin crystallization mother liquor recovered in example 3 were concentrated under reduced pressure (-0.089MPa) by an MVR evaporation system to 15% of the original volume to obtain 469.65 g of a concentrated solution. Transferring the concentrated solution into an acidification cyclization reaction kettle, adding 15.13 g of the silica gel sulfonic acid recovered in the example 3 into the concentrated solution, heating to 115 ℃, reacting for 90min, and filtering solid acid after the reaction is finished to obtain a hydantoin aqueous solution.

468.3 g of hydantoin aqueous solution transferred into a decoloring kettle is added with 3.74 g of activated carbon, decoloring treatment is carried out for 50min at the temperature of 80 ℃, the activated carbon is removed by filtration, and light yellow filtrate 468.0 g is obtained, wherein the mass percentage of the hydantoin is 79.00 wt%, and the hydantoin yield is 103.91% (calculated by hydroxyl acetonitrile). Transferring the filtrate into a crystallization kettle, cooling to 30 ℃, separating out a large amount of white precipitate, filtering and separating the white precipitate, drying to obtain 365.98 g of white hydantoin with the purity of 99.0 percent, the single extraction rate of the hydantoin of 98 percent, and the weight of the crystallization mother liquor obtained by filtering is 95.0 g, and the hydantoin content in the crystallization mother liquor is 7.07wt percent by mass through liquid chromatography analysis. The recovered silica gel sulfonic acid after filtration is washed by a small amount of water and then directly recycled to the next acidification and cyclization reaction, the weight of the recovered silica gel sulfonic acid is 15.13 g after drying, and the recovery rate of the solid acid catalyst is 100%. The hydantoin crystallization mother liquor is recycled to the next step of concentration treatment of the reaction solution after degassing.

Example 5

2698.5 g of deionized water is added into a 4000ml pressure-resistant ammonia carbonylation reactor (material is 316L) with a feeding and stirring device, 240.4 g of ammonia gas and 444.4 g of carbon dioxide gas are introduced, the feeding molar ratio of the ammonia gas to the carbon dioxide is controlled to be 1.40:1, the feeding molar ratio of the ammonia to the water is controlled to be 1:10.601, and then the temperature is raised to 70 ℃ to obtain ammonium bicarbonate mixed solution. 399.0 g (3.50mol) of an aqueous hydroxyacetonitrile solution at a temperature of 70 ℃ and 50 wt% and a pH of 4.0 were added thereto at a constant rate of 100g/min so that the molar feed ratio of ammonia to hydroxyacetonitrile was 4.0:1 and the feed time of the aqueous hydroxyacetonitrile solution was 9.1min, and during the addition of the aqueous hydroxyacetonitrile solution, the temperature in the aminocarbonylation reactor was raised to 100 ℃ and immediately after the addition of the aqueous hydroxyacetonitrile solution, the temperature was raised to 125 ℃ and the reaction was stirred for 90min under a pressure of 3.8MPa, wherein the volume of the reaction mixture was 92% of the volume of the aminocarbonylation reactor (i.e., the liquid level was 92%). After the reaction, the reaction mixture was cooled to 85 ℃ and depressurized to normal pressure, whereby 3782.3 g of the aminocarbonylation reaction solution was obtained.

The obtained aminocarbonylation reaction solution was subjected to stripping in a stripping column (bottom temperature 105 ℃ C., top temperature 100 ℃ C.) so that the residual amount of ammonia in the degassed reaction solution obtained by stripping was less than 50ppm, thereby obtaining 3211.0 g of a degassed reaction solution. The obtained reaction solution after degassing is concentrated under reduced pressure (-0.086MPa) by adopting an MVR evaporation system to obtain 481.65 g of concentrated solution, wherein the concentration is 15% of the original volume. Transferring the concentrated solution into an acidification cyclization reaction kettle, adding 23.45 g of D61 macroporous strong-acid styrene cation exchange resin (purchased from Tianjinbo hong resin science and technology Co., Ltd.) into the concentrated solution, heating to 100 ℃, reacting for 100min, and filtering solid acid after the reaction is finished to obtain hydantoin aqueous solution.

481.6 g of hydantoin aqueous solution transferred into a decoloring kettle is added with 1.4 g of activated carbon, decoloring treatment is carried out for 60min at the temperature of 90 ℃, the activated carbon is removed by filtration, and then 480.9 g of light yellow filtrate is obtained, wherein the mass percentage of hydantoin is 72.42 wt%, and the yield of hydantoin is 99.5% (calculated by hydroxyl acetonitrile) by liquid chromatography analysis. Transferring the filtrate into a crystallization kettle, cooling to 10 ℃, separating out a large amount of white precipitate, filtering and separating the white precipitate, drying to obtain 342.93 g of white hydantoin with the purity of 99.0 percent and the single extraction rate of the hydantoin of 97 percent, wherein the weight of the crystallization mother liquor obtained by filtering is 130.97 g, and the mass percentage of the hydantoin in the crystallization mother liquor is 6.09wt percent by liquid chromatography analysis. The macroporous strong-acid cation exchange resin recovered after filtration is washed by a small amount of water and then directly circulated to the next acidification cyclization reaction, the weight of the recovered macroporous strong-acid cation exchange resin is 23.45 g after drying, and the recovery rate of the solid acid catalyst is 100%.

Example 6

2698.5 g of deionized water is added into a 4000ml pressure-resistant aminocarbonylation reactor (material is 316L) with a feeding and stirring device, 240.4 g of ammonia gas and 444.4 g of carbon dioxide gas are introduced, the feeding molar ratio of the ammonia gas to the carbon dioxide is controlled to be 1.40:1, then the temperature is raised to 70 ℃, and the feeding molar ratio of the ammonia to the water is 1:10.601, so as to obtain a mixed solution of ammonium bicarbonate. 399.0 g (3.50mol) of an aqueous hydroxyacetonitrile solution at 50 wt%, pH 2.0 and 70 ℃ was added thereto at a constant rate of 100g/min so that the molar feed ratio of ammonia to hydroxyacetonitrile was 4.0:1 and the feed time of the aqueous hydroxyacetonitrile solution was 9.1min, and during the addition of the aqueous hydroxyacetonitrile solution, the temperature in the aminocarbonylation reactor was raised to 100 ℃ and immediately after the addition of the aqueous hydroxyacetonitrile solution, the temperature was raised to 110 ℃ and the reaction was stirred for 90min under a pressure of 3.2MPa, wherein the volume of the reaction mixture was 92% of the volume of the aminocarbonylation reactor (i.e., the liquid level was 92%). After the reaction, the reaction mixture was cooled to 85 ℃ and depressurized to normal pressure, whereby 3782.3 g of the aminocarbonylation reaction solution was obtained.

The obtained aminocarbonylation reaction solution was subjected to stripping in a stripping column (bottom temperature 105 ℃ C., top temperature 100 ℃ C.) so that the residual amount of ammonia in the degassed reaction solution obtained by stripping was less than 50ppm, thereby obtaining 3211.0 g of a degassed reaction solution. The obtained reaction solution after degassing is concentrated under reduced pressure (-0.09MPa) by adopting an MVR evaporation system to obtain 481.65 g of concentrated solution, wherein the concentrated solution is concentrated to 15% of the original volume. The concentrated solution is acidifiedAdding sulfonated ferric oxide (Fe) into the cyclization reaction kettle₂O₃/SO₄(ii) a For example, cn201710866706.x)23.45 g, then heated to 100 ℃, reacted for 90min, and after the reaction was over, the solid acid was filtered to obtain an aqueous hydantoin solution.

481.2 g of hydantoin aqueous solution transferred into a decoloring kettle is added with 1.4 g of activated carbon, decoloring treatment is carried out for 60min at the temperature of 90 ℃, the activated carbon is removed by filtration, and then 480.9 g of light yellow filtrate is obtained, wherein the mass percentage of hydantoin is 72.42 wt%, and the yield of hydantoin is 99.5% (calculated by hydroxyl acetonitrile) by liquid chromatography analysis. Transferring the filtrate into a crystallization kettle, cooling to 10 ℃, separating out a large amount of white precipitate, filtering the white precipitate, drying to obtain 342.93 g of white hydantoin with the purity of 99.0 percent and the single extraction rate of the hydantoin of 97 percent, wherein the weight of the crystallization mother liquor obtained by filtering is 130.07 g, and the mass percentage of the hydantoin in the crystallization mother liquor is 6.18 percent by weight by liquid chromatography analysis. Washing the sulfonated ferric oxide recovered after filtration with a small amount of water, and directly circulating to next acidification and cyclization reaction, wherein the sulfonated ferric oxide (Fe) recovered₂O₃/SO₄) After drying, the weight was 23.45 g, and the recovery rate of the solid acid catalyst was 100%.

Comparative example 1

2364 g of deionized water is added into a 5000ml pressure-resistant ammonia carbonylation reactor (material is 316L) with a feeding and stirring device, 216.5 g of ammonia gas and 420.4 g of carbon dioxide gas are introduced, the feeding molar ratio of the ammonia gas to the carbon dioxide is controlled to be 1.333:1, the feeding molar ratio of the ammonia to the water is controlled to be 1:10.313, and then the temperature is raised to 70 ℃ to obtain ammonium bicarbonate mixed solution. 453.8 g (3.185mol) of a 40 wt% aqueous solution of hydroxyacetonitrile at 70 ℃ having a pH of 3.0 were added thereto at a uniform rate of 50g/min so that the molar feed ratio of ammonia to hydroxyacetonitrile was 4.0:1 and the feed time of the aqueous hydroxyacetonitrile solution was 9.1 min. During the course of adding the aqueous hydroxyacetonitrile solution, the temperature in the aminocarbonylation reactor was raised to 100 ℃, and immediately after the addition of the aqueous hydroxyacetonitrile solution, the temperature was raised to 110 ℃, and the reaction was stirred for 90 minutes under a pressure of 2.2MPa, wherein the volume of the reaction mixture was 67% of the volume of the aminocarbonylation reactor (i.e., the liquid level was 67%). After the reaction, the reaction mixture was cooled to 80 ℃ and depressurized to normal pressure to obtain 3452.8 g of the aminocarbonylation reaction solution.

The obtained aminocarbonylation reaction solution was subjected to stripping in a stripping column (bottom temperature 105 ℃ C., top temperature 100 ℃ C.) so that the residual amount of ammonia in the degassed reaction solution obtained by stripping was less than 50ppm, thereby obtaining 2930.6 g of a degassed reaction solution. The obtained reaction solution after degassing is concentrated under reduced pressure (-0.094MPa) by adopting an MVR evaporation system to obtain 586.12 g of concentrated solution, wherein the concentrated solution is concentrated to 20% of the original volume. And transferring the concentrated solution into an acidification cyclization reaction kettle, adding 23.45 g of silica gel sulfonic acid into the concentrated solution, heating to 100 ℃, reacting for 60min, and filtering solid acid after the reaction is finished to obtain a hydantoin aqueous solution.

585.0 g of hydantoin aqueous solution transferred into a decoloring kettle is added with 1.4 g of activated carbon, decoloring treatment is carried out for 60min at the temperature of 90 ℃, the activated carbon is removed by filtration, and light yellow filtrate 584.5 g is obtained, wherein the mass percentage of the hydantoin is 42.5 wt%, and the hydantoin yield is 78% (calculated by hydroxyl acetonitrile). Transferring the filtrate into a crystallization kettle, cooling to 20 ℃, separating out a large amount of white precipitate, filtering and separating the white precipitate, drying to obtain 175.66 g of white hydantoin with the purity of 99.0 percent and the single extraction rate of 70 percent of hydantoin, wherein the weight of crystallization mother liquor obtained by filtering is 400.84 g, and the mass percentage of the hydantoin in the crystallization mother liquor is 17.6 percent by weight by liquid chromatography analysis. The recovered silica gel sulfonic acid after filtration is washed by a small amount of water and then directly recycled to the next acidification and cyclization reaction, the weight of the recovered silica gel sulfonic acid is 23.25 g after drying, and the recovery rate of the solid acid catalyst is 99.15%.

Comparative example 2

2364 g of deionized water is added into a 4000ml pressure-resistant zirconium-lined aminocarbonylation reactor with a feeding and stirring device, 216.5 g of ammonia gas and 420.4 g of carbon dioxide gas are introduced, the feeding molar ratio of the ammonia gas to the carbon dioxide is controlled to be 1.333:1, the feeding molar ratio of the ammonia to the water is controlled to be 1:10.313, and then the temperature is raised to 70 ℃ to obtain ammonium bicarbonate mixed solution. 453.8 g (3.185mol) of an aqueous hydroxyacetonitrile solution at 70 ℃ having a pH of 3.0 and 40 wt% were added thereto at a uniform rate of 50g/min so that the molar feed ratio of ammonia to hydroxyacetonitrile was 4.0:1 and the feed time of the aqueous hydroxyacetonitrile solution was 9.1 min. During the course of adding the aqueous hydroxyacetonitrile solution, the temperature in the aminocarbonylation reactor was raised to 100 ℃, and after the addition of the aqueous hydroxyacetonitrile solution was completed, the temperature was raised to 110 ℃ immediately, and the reaction was stirred for 90 minutes under a pressure of 3.5MPa, wherein the volume of the reaction mixture was 92% of the volume of the aminocarbonylation reactor (i.e., the liquid level was 92%). After the reaction, the reaction mixture was cooled to 80 ℃ and depressurized to normal pressure to obtain 3452.8 g of the aminocarbonylation reaction solution.

The obtained aminocarbonylation reaction solution was subjected to stripping in a stripping column (bottom temperature 105 ℃ C., top temperature 100 ℃ C.) so that the residual amount of ammonia in the degassed reaction solution obtained by stripping was less than 50ppm, thereby obtaining 2930.6 g of a degassed reaction solution. The obtained reaction solution after degassing was concentrated under reduced pressure (-0.095MPa) using MVR evaporation system, and 20% of the original volume was concentrated to obtain 586.12 g of concentrated solution. And transferring the concentrated solution into an acidification cyclization reaction kettle, adding 23.45 g of silica gel sulfonic acid into the concentrated solution, heating to 100 ℃, reacting for 60min, and filtering solid acid after the reaction is finished to obtain a hydantoin aqueous solution.

585.1 g of hydantoin aqueous solution transferred to a decoloring kettle is added with 1.4 g of activated carbon, decoloring treatment is carried out for 60min at 90 ℃, the activated carbon is removed by filtration, and a light yellow filtrate 584.5 g is obtained, wherein the mass percentage of hydantoin is 46.3 wt%, the mass percentage of glycine is 5.72 wt%, the yield of hydantoin is 85% (calculated as hydroxyl acetonitrile), and the yield of glycine is 14% (calculated as hydroxyl acetonitrile) by liquid chromatography analysis. Transferring the filtrate into a crystallization kettle, cooling to 20 ℃, separating out a large amount of white precipitate, filtering and separating the white precipitate, drying to obtain 218.77 g of white hydantoin with the purity of 99.0 percent and the single extraction rate of 80 percent of hydantoin, wherein the weight of the crystallization mother liquor obtained by filtering is 365.73 g, and the mass percent of the hydantoin and the mass percent of the glycine in the crystallization mother liquor is 14.08 percent by weight and 9.14 percent by weight through liquid chromatography analysis. The recovered silica gel sulfonic acid after filtration is washed by a small amount of water and then directly circulated to the next batch of acidification cyclization reaction, the weight of the recovered silica gel sulfonic acid is 24.25 g after drying, and the recovery rate of the solid acid catalyst is more than 100 percent because the recovered catalyst carries glycine products.

Comparative example 3

2364 g of deionized water is added into a 4000ml pressure-resistant aminocarbonylation reactor (material is 316L) with a feeding and stirring device, 216.5 g of ammonia gas and 420.4 g of carbon dioxide gas are introduced, the feeding molar ratio of the ammonia gas to the carbon dioxide is controlled to be 1.333:1, the feeding molar ratio of the ammonia to the water is controlled to be 1:10.313, and then the temperature is raised to 70 ℃ to obtain ammonium bicarbonate mixed solution. 453.8 g (3.185mol) of an aqueous hydroxyacetonitrile solution at 70 ℃ having a pH of 3.0 and 40 wt% were added thereto at a uniform rate of 50g/min so that the molar feed ratio of ammonia to hydroxyacetonitrile was 4.0:1 and the feed time of the aqueous hydroxyacetonitrile solution was 9.1 min. During the course of adding the aqueous hydroxyacetonitrile solution, the temperature in the aminocarbonylation reactor was raised to 100 ℃, and after the addition of the aqueous hydroxyacetonitrile solution was completed, the temperature was raised to 110 ℃ immediately, and the reaction was stirred for 90 minutes under a pressure of 3.5MPa, wherein the volume of the reaction mixture was 92% of the volume of the aminocarbonylation reactor (i.e., the liquid level was 92%). After the reaction, the reaction mixture was cooled to 80 ℃ and depressurized to normal pressure to obtain 3452.8 g of the aminocarbonylation reaction solution.

The obtained aminocarbonylation reaction solution was subjected to stripping in a stripping column (bottom temperature 105 ℃ C., top temperature 100 ℃ C.) so that the residual amount of ammonia in the degassed reaction solution obtained by stripping was less than 50ppm, thereby obtaining 2930.6 g of a degassed reaction solution. The obtained reaction solution after degassing is concentrated under reduced pressure (-0.086MPa) by adopting an MVR evaporation system to obtain 586.12 g of concentrated solution, wherein the concentration is 20% of the original volume. Transferring the concentrated solution into an acidification cyclization reaction kettle, adding 87.92 g of 98 wt% sulfuric acid into the concentrated solution, heating to 100 ℃, and reacting for 60min to obtain a cyclization reaction solution.

675.0 g of the cyclization reaction solution transferred into a decolorization kettle was added with 1.4 g of activated carbon, decolorization was carried out at 90 ℃ for 60min, and the activated carbon was removed by filtration to obtain 674.04 g of pale yellow filtrate, wherein the hydantoin content by mass was 42.5% and the hydantoin yield was 90% (based on hydroxyacetonitrile) by liquid chromatography. Transferring the filtrate into a crystallization kettle, cooling to 20 ℃, separating out a large amount of white precipitate, filtering and separating the white precipitate, drying to obtain 173.62 g of white hydantoin with the purity of 99.0 percent and the single extraction rate of 60 percent of hydantoin, wherein the weight of the crystallization mother liquor obtained by filtering is 495.05 g, and the mass percentage of the hydantoin in the crystallization mother liquor is 23.1 percent by weight by liquid chromatography analysis. The hydantoin crystallization mother liquor is circulated to the next acidification and cyclization reaction step, but due to the accumulation of impurities in the crystallization mother liquor and the consumption of sulfuric acid, part of waste acid needs to be periodically extracted for separate treatment (the amount of the waste acid in each batch of reaction is about 20-30% of the total mass of the crystallization mother liquor), and the treatment method comprises the following steps: neutralizing with alkali, concentrating, and obtaining sulfate as byproduct.

Finally, the above embodiments are only for illustrating the technical solutions of the present invention and not for limiting, although the present invention has been described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that modifications or equivalent substitutions may be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all of them should be covered in the claims of the present invention.

Claims

1. A clean production method of hydantoin, which comprises the following steps:

2. The process according to claim 1, wherein in step (1), the molar ratio of the hydroxyacetonitrile to the ammonia or ammonia-releasing precursor compound is 1 (3.5-4.3), the molar ratio of the ammonia or ammonia-releasing precursor compound to the carbon dioxide or carbon dioxide-releasing precursor compound is (1.3-1.4): 1, and the molar ratio of the ammonia or ammonia-releasing precursor compound to water is 1 (10-12), wherein the amounts of the ammonia-releasing precursor compound and the carbon dioxide-releasing precursor compound are calculated as ammonia and carbon dioxide, respectively.

3. The process according to claim 1 or 2, wherein in step (1), the aminocarbonylation reaction is carried out in the absence of zirconium at a level of 85% to 95%;

preferably, in the step (1), hydroxyl acetonitrile, ammonia, carbon dioxide and water are used as raw materials;

preferably, in the step (1), the hydroxy acetonitrile is a hydroxy acetonitrile aqueous solution with the mass percentage of 20-65 wt% and the pH value of 2-4;

preferably, in the step (1), before the hydroxy acetonitrile is added, the ammonia or the ammonia release precursor compound, the carbon dioxide or the carbon dioxide release precursor compound and the water are mixed to obtain a mixed solution of ammonium bicarbonate; preferably, in the step (1), before mixing the hydroxy acetonitrile water solution and the ammonium bicarbonate mixed solution, the temperature of the hydroxy acetonitrile water solution and the temperature of the ammonium bicarbonate mixed solution are respectively increased to 50-70 ℃;

preferably, in the step (1), the aminocarbonylation reaction is performed for 60-120 min at a temperature of 100-125 ℃ and a pressure of 2.0-4.0 MPa.

4. The method according to any one of claims 1 to 3, wherein in the step (2), unreacted carbon dioxide and ammonia are removed from the ammonia carbonylation reaction liquid obtained in the step (1) by stripping or under a negative pressure condition;

preferably, the residual amount of ammonia in the reaction solution after degassing is less than 50 ppm;

preferably, the bottom temperature of the stripping tower is controlled to be 100-110 ℃, and the top temperature is controlled to be 98-100 ℃, so that the stripping treatment is carried out;

preferably, the ammonia and carbon dioxide removed in step (2) are recycled to said step (1).

5. The method according to any one of claims 1 to 4, wherein, in the step (2), the reaction solution after degassing is subjected to a concentration treatment under reduced pressure; preferably, the reaction solution after degassing is concentrated to 15-40% of the original volume;

preferably, in the step (2), the feeding mass of the solid acid is 2-10% of the mass of the concentrated solution;

preferably, in the step (2), the solid acid is one or more of a sulfonated high molecular material, a sulfonated silicon dioxide or a sulfonated ferric oxide; preferably, the polymer material subjected to sulfonation treatment is cation exchange resin subjected to sulfonation treatment; preferably, the sulfonated silica is silica gel sulfonic acid;

preferably, in the step (2), the temperature of the cyclization reaction is 95-115 ℃, and the reaction time is 90-120 min;

preferably, in step (2), the solid acid is isolated by centrifugation or filtration.

6. The process according to any one of claims 1 to 5, wherein in step (3), the aqueous hydantoin solution obtained in step (2) is subjected to said decolorization by adding activated carbon;

preferably, in the step (3), the adding amount of the activated carbon is 0.2 to 0.8 percent of the mass of the hydantoin aqueous solution;

preferably, in the step (3), the decoloring temperature is 80-100 ℃, and the decoloring time is 50-90 min;

preferably, in step (3), the activated carbon is removed by separation by centrifugation or filtration to obtain the decolorized solution;

preferably, in the step (3), the obtained decolorized solution is cooled to 0-30 ℃ for crystallization;

preferably, in step (3), the hydantoin and the crystallization mother liquor are separated by centrifugation or filtration;

preferably, the crystallization mother liquor in step (3) is recycled to step (2) to participate in the concentration treatment.

7. The process according to any of claims 1-6, wherein the clean production process of hydantoin comprises the steps of:

8. The process of any one of claims 1 to 7, wherein the process is one or more of a batch, semi-continuous or continuous process.

9. An apparatus for implementing the method according to any one of claims 1-8, wherein the apparatus comprises:

10. The apparatus of claim 9, wherein the transamination reaction unit further comprises a preheater and a mixer, and the mixer is fluidly connected to the transamination reactor, the preheater being fluidly connected to the mixer; preferably, the mixer is a micron-sized reaction channel or an SV-type static mixer;

preferably, the evaporation concentration system is an MVR evaporation system;

preferably, the first solid-liquid separation device and the second solid-liquid separation device are centrifugal devices or filtering devices;

preferably, the crystallization unit further comprises a third solid-liquid separation device and a drying system disposed downstream of the crystallization vessel in fluid communication; preferably, the third solid-liquid separation device is a centrifugal device or a filtering device;

preferably, the material of the ammonia carbonylation reactor is 316L;

preferably, the preheater, the ammonia carbonylation reactor, the evaporation concentration system, the acidification cyclization reaction kettle, the decoloration kettle, the crystallization kettle and the drying system are respectively provided with a temperature regulation auxiliary device.