KR100473333B1 - Method and apparatus for preparing hydrazodicarbonamide using urea as starting material - Google Patents

Abstract

The present invention relates to a method and apparatus for producing hydrazodicarbonamide economically and environmentally friendly using urea as a starting material, comprising: a pyrolysis furnace for pyrolyzing urea to obtain burette and ammonia; A recrystallization reactor for purifying the burette obtained in the pyrolysis furnace; A first reactor for reacting said recrystallized burette with a metal hypohalogen compound, or a halogen and a base, to obtain a monohalo burette metal salt; A second reactor for synthesizing hydrazodicarbonamide by reacting the monohaloburet metal salt obtained in the first reactor with ammonia; And an ammonia evaporator separating the hydrazodicarbonamide and the excess amount of ammonia obtained in the second reactor and transferring the separated ammonia to the ammonia concentrator. Here, the ammonia concentrator is preferably configured to concentrate the excess amount of ammonia and the ammonia obtained in the pyrolysis furnace and to supply the ammonia.

Description

Method and apparatus for preparing hydrazodicarbonamide using urea as starting material {method and apparatus for preparing hydrazodicarbonamide using urea as starting material}

The present invention relates to a method and apparatus for preparing hydrazodicarbonamide using urea as a starting material. More specifically, a biuret is synthesized using urea, and is produced in the process of synthesizing the obtained burette and burette. And a method and apparatus for producing hydrazodicarbonamide economically and environmentally friendly by reacting ammonia.

Hydrazodicarbonamide (HDCA) is a compound useful as a raw material of azodicarbonamide, which is one of the most widely used blowing agents in the world, and as shown in Scheme 1, hydrazodicarbonamide (1) ) Can be obtained by oxidizing with a suitable oxidizing agent.

Such a method for producing hydrazodicarbonamide includes (i) a method of using hydrazine as a starting material, (ii) a method of directly synthesizing from urea, and (iii) a semicarbazide obtained by using urea. The method of converting zayed to hydrazodicarbonamide, (iv) using a burette as a starting material, and the like are known.

The method of using hydrazine as a starting material is a method of synthesizing hydrazodicarbonamide by reacting 1 mole of hydrazine (3) with 2 moles of urea (4).

The reaction has the advantage that the reaction process is simple, but the synthesis procedure of the hydrazine to be used as a starting material is difficult and costs a lot of synthesis. Representative hydrazine synthesis methods include the Raschig process and ketazine. The hydrazines produced by these methods require enormous energy and facility costs due to the concentration and hydrolysis processes. Due to this, there is a problem that the production cost rises. In addition, hydrazine may also be prepared by the urea process of reacting urea, sodium hypochlorite (NaOCl) and sodium hydroxide, but this method requires an excess of sodium hydroxide and is expensive to remove by-product sodium carbonate. It is uneconomical and environmentally friendly due to the consumption of chemicals and chemicals.

Scheme 3 below shows a method for preparing hydrazodicarbonamide directly from urea. As shown in Scheme 3 below, 3 moles of urea, 4 moles of sodium hydroxide, and 1 mole of chlorine (Cl ₂ ) are reacted. 1 mole of hydrazodicarbonamide can be obtained. However, since this method requires an excessive amount of reactants, the manufacturing cost is expensive, the synthesis procedure is difficult, and a large amount of ammonia is generated as a by-product, which is undesirable in terms of environment.

Scheme 4 below is another method of synthesizing hydrazodicarbonamide, which shows a method of obtaining semicarbazide using urea and converting the obtained semicarbazide to hydrazodicarbonamide. As shown in Scheme 4 below, by reacting urea with sodium hypochlorite (NaOCl) to obtain a monochlorourea sodium salt, and then reacted with excess ammonia in the presence of a catalyst to obtain an intermediate product semicarbazide, The reaction of semicarbazide with urea can produce hydrazodicarbonamide, the final product.

        However, this reaction is not only economically disadvantageous because the semi-carbazide is synthesized by using an excess of about 500 times of ammonia or an expensive catalyst with respect to the intermediate monochlorourea sodium salt. In order to convert the carbazide to hydrazodicarbonamide, there is a problem in that the entire reaction process is lengthened because one more reaction is required.

Scheme 5 below shows a method for synthesizing hydrazodicarbonamide using a burette as a starting material (see International Application No. PCT / KR00 / 00180), as shown in Scheme 5 below, a metal hypohalogen (MOX) in the burette ) To obtain monohaloburette. Hydrazodicarbonamide can be manufactured by making the obtained monohalo biuret react with ammonia.

       However, the method for synthesizing hydrazodicarbonamide using the burette as a starting material is not only expensive or contains a large amount of impurities, but also separates ammonia to synthesize hydrazodicarbonamide. Since the reaction must be reacted with the burette by the injection, there is a problem that the whole process is performed economically and environmentally friendly.

It is therefore an object of the present invention to provide a process for producing hydrazodicarbonamide economically and environmentally friendly from urea, which is a low cost and easy to purchase starting material.

Another object of the present invention is to provide a method and apparatus for producing hydrazodicarbonamide, which can minimize the formation of by-products and the input of raw materials.

It is still another object of the present invention to provide a method and apparatus for preparing hydrazodicarbonamide, which can continuously perform the whole process to produce hydrazodicarbonamide in high yield.

In order to achieve the above object, the present invention comprises the steps of pyrolyzing urea to obtain a burette and ammonia of the formula (1); Reacting the obtained burette with a metal hypohalogen compound or a halogen and a base to obtain a monohaloburet metal salt of the following Chemical Formula 2 or 3; And it provides a method for producing hydrazodicarbonamide comprising the step of reacting the obtained monohaloburet metal salt and ammonia.

In Formulas 2 and 3, M represents a metal, and X represents a halogen. Here, the pyrolysis temperature of the urea is 100 to 300 ℃, the pyrolysis process of the urea is carried out while removing ammonia from the reaction system, wherein the ammonia removed is preferably reacted with the monohaloburet metal salt.

The invention also provides a pyrolysis furnace for pyrolyzing urea to obtain burettes and ammonia; A recrystallization reactor for purifying the burette obtained in the pyrolysis furnace; A first reactor for reacting said recrystallized burette with a metal hypohalogen compound, or a halogen and a base, to obtain a monohalo burette metal salt; A second reactor for synthesizing hydrazodicarbonamide by reacting the monohaloburet metal salt obtained in the first reactor with ammonia; And an ammonia evaporator separating the hydrazodicarbonamide and the excess amount of ammonia obtained in the second reactor and transferring the separated ammonia to the ammonia concentrator.

Here, the ammonia concentrator is preferably configured to concentrate the excess amount of ammonia and ammonia obtained in the pyrolysis furnace and to supply the second reactor, and the pyrolysis furnace does not react with isocyanic acid inside the pyrolysis furnace. It is preferable that a gas injection means for injecting an inert gas is further formed, or further, decompression means for removing ammonia from the pyrolysis furnace by depressurizing the pyrolysis furnace is provided.

Hereinafter, with reference to the accompanying drawings will be described in detail a manufacturing method and apparatus for producing hydrazodicarbonamide according to the present invention.

In order to prepare the hydrazodicarbonamide according to the present invention, by first heating the urea above the melting point and pyrolysis to obtain a burette and ammonia represented by the formula (1). Burettes are generally widely used as precursors for pharmaceuticals, herbicides, analytical reagents, and the like, and are used in large quantities as feed for ruminants. In addition, the derivatives of burettes are reported to have the characteristics of physiological and chemotherapeutic agents, and have various applications in the plastic or resin fields. Synthesis of the burette by thermal decomposition of such elements is shown in Scheme 6 below.

      As shown in Scheme 6, the pyrolysis of 2 moles of urea produces a burette while 1 mole of ammonia is removed. Looking at this in detail, as shown in Scheme 7, urea is first pyrolyzed to give isocyanic acid. ) And ammonia are produced, and the isocyanic acid and urea react to produce the desired burette.

     The synthesis of burettes by pyrolysis of such urea has the advantage of simple reaction and easy operation of the reaction process. However, burette and isocyanic acid react with triuret or cyanuric acid during the production of burette. A large amount of impurities such as cyanuric acid) is generated, and the conversion rate of urea to burette is low. If the reaction temperature is increased to increase the conversion rate and the reaction time is increased, the amount of impurities such as cyanuric acid and triure are also increased, and if the reaction temperature is reduced to suppress the production of impurities, the reaction rate is too low and economically. The process cannot be performed. In the present invention, in order to increase the yield of the burette and reduce the amount of impurities, it is preferable to maintain the pyrolysis temperature of the urea at 100 to 300 ° C, more preferably at 130 to 170 ° C.

In addition, by injecting an inert gas that does not react with isocyanic acid such as air or nitrogen into the reactor, lowering the pressure of the reaction system, or both methods simultaneously, ammonia, a byproduct generated during the reaction, is effectively removed from the reactor. By removing, the reaction rate can be increased and the generation of impurities can be suppressed. In this case, the inert gas may be a liquid organic material that can be converted into an inert gas that does not react with isocyanic acid in the reaction system.

In addition, if necessary, a catalyst for increasing the pyrolysis reaction rate may be used, and the catalyst may include inorganic acid catalysts such as nitric acid, hydrochloric acid and sulfuric acid, acidic catalysts such as thionyl chloride, and phosphorus such as disodium phosphate. A substance and the like can be used, and the amount of the catalyst added is preferably 0.001 to 0.5 moles, more preferably 0.01 to 0.3 moles per mole of urea.

The burette thus obtained is reacted with a metal hypohalogen compound or halogen and a base to obtain a monohaloburet metal salt of the following formula (2) or (3).

[Formula 2]

[Formula 3]

      In Formulas 2 and 3, M represents a metal, and X represents a halogen.

The method for obtaining a monohaloburet metal salt directly by reacting a burette with a metal hypohalogen compound is shown in Scheme 8 below, and a specific example thereof is shown in Scheme 9 below.

       In the above scheme, M represents metal and X represents halogen.

Referring to Scheme 9 above, the biuret is reacted with sodium hypochlorite (NaOCl) to obtain a chloroburet sodium salt. Since the reaction is exothermic, it is preferable to keep the temperature of the reaction system low. However, the produced chloroburet sodium salt is relatively heat stable, and thus production at room temperature is possible. The preferred reaction temperature is 60 ° C. or less, preferably -10 to 60 ° C., more preferably -5 to 35 ° C., and considering the economical efficiency of the reaction and ease of operation, a metal hypophosphite such as sodium hypochlorite per mole of burette is considered. The reaction molar ratio of halogen is preferably 0.1 to 2 moles. In this case, when the reaction molar ratio of the metal hypohalogen is less than 1 mole, the excess burette may be recovered and used again. In the above reaction, when the reaction ratio of the metal hypohalogen is less than 0.1 mole or the reaction temperature is less than -10 ° C., the reaction time becomes too long, and when the reaction molar ratio exceeds 2 moles, there is a problem of cost increase and side reactions. If the reaction temperature exceeds 60 ℃ produced monohalo burette metal salt is unstable to heat, there is a problem that decomposes. The chloroburet sodium salt produced under the conditions as described above can be used directly or after storage for subsequent reactions.

An example of a process of obtaining a monohaloburet metal salt of Chemical Formula 2 or 3 by reacting a burette with a halogen and a base is shown in Scheme 10 below. As shown in Scheme 10, the biuret is reacted with a halogen (X ₂ ) or a halogen compound such as chlorine to obtain a monohaloburet (5), and then a base, preferably sodium hydroxide, potassium hydroxide, calcium hydroxide, and the like. The same metal hydroxide may be added to obtain a monohaloburet metal salt.

In the above scheme, M represents metal and X represents halogen.

At this time, the reaction temperature is lower in consideration of the fact that the reaction until the halogenation of the burette to obtain the monohalo burette 5 is exothermic, specifically, below 60 ° C, preferably -10 to 60 ° C, more preferably Maintaining at -5 to 30 ℃ is good for the reaction rate and the safety of the reaction. As a modified method, the metal hydroxide may first be mixed with the burette and then halogen reacted to obtain the monohaloburet metal salt. Since this reaction is also exothermic, it is preferable to keep the temperature of the reaction system low, specifically in the range of -10 to 60 ° C, more preferably -5 to 30 ° C. If the temperature of the reaction is less than -10 ℃ the reaction rate is too slow, if it exceeds 60 ℃ there is a problem that the resulting monohalo burette metal salt is decomposed due to heat unstable. The monohaloburet metal salt is obtained in the form of a 3-monohalo burette metal salt or a 1-monohalo burette metal salt as in Scheme 11 below, but the main product is a 3-monohalo burette metal salt.

       When the monohaloburet metal salt thus obtained is reacted with ammonia produced by pyrolysis of the urea, hydrazodicarbonamide is synthesized, and the reaction route is Favorskii reaction of Scheme 12 or Hoffman of reaction scheme 13 (Hoffman) is assumed to be similar to the potential response.

Referring to Scheme 12, when the nitrogen atom of the anion reacts between the molecules in the monohaloburet metal salt (8), metal halides are dropped and N-N bonds are generated to generate an unstable diaziridinone derivative (9). The diaziridinone derivative (9) thus produced immediately reacts with highly reactive ammonia to produce hydrazodicarbonamide. In addition, referring to Scheme 13, it is assumed that the monohaloburet metal salt is converted into a compound containing an isocyanate group, and the converted isocyanate compound is reacted with highly reactive ammonia to be converted into hydrazodicarbonamide.

In the synthesis reaction of the monohaloburet metal salt 8 with ammonia which is a pyrolysis byproduct of urea, the reaction temperature is preferably 0 to 150 ° C, more preferably 30 to 150 ° C in view of the reaction rate and efficiency. At this time, if the reaction temperature is less than 0 ℃ the reaction rate is too slow and economical, if it exceeds 150 ℃ there is a problem that the internal pressure of the reactor rises due to the increase in the vapor pressure due to ammonia vaporization is expensive equipment costs.

In addition, ammonia may use any of gaseous ammonia, liquid ammonia, and ammonia hydrate. Ammonia is preferably used in excess in order to increase the reaction rate. Specifically, 1 to 1000 moles, preferably 2 to 500 moles, and more preferably 5 to moles, relative to 1 mole of the monohaloburet metal salt as the starting material. 100 moles are used. At this time, an excess of ammonia except 1 mol of ammonia reacting with 1 mol of monohaloburet metal salt may be recovered after the reaction and added to the next reaction. When the reaction temperature is a high temperature while using ammonia, a pressure may be applied to the reaction system to prevent evaporation of the reactant ammonia to increase the reaction speed and efficiency, and the preferred pressure range is 1 to 100 kgf / cm 2.

According to the present invention, a high yield can be obtained without using a catalyst. However, using a catalyst is useful because the reaction time is shortened and the reaction efficiency is improved. In this case, at least one selected from the group consisting of sulfates, chlorides, carbonates or hydroxides of amphoteric metals or basic metals, and metal organic compounds thereof as the catalyst, 0.001 to 1 mol, preferably 1 mol of the monohaloburet metal salt of Formula 1 Preferably, 0.01 to 0.5 moles may be added, or 0.05 to 3.0 moles of inorganic acids such as sulfuric acid, hydrochloric acid, and nitric acid may be added.

On the other hand, water can be used as a solvent of the reactant burette or as a solvent of the whole reaction system. One or more second solvents such as aprotic solvents such as dimethyl sulfoxide and dimethylacetamide may be added. Although the usage-amount of a 2nd solvent does not need to specifically limit, A preferable usage-amount is 0.1-50 times amount with respect to the total weight of water, Preferably it is 0.2-3.0 times amount. In addition, the second solvent may be added from the beginning of the reaction as a solvent of the burette, or may be added after mixing the burette solution and the sodium hypochlorite solution.

A method for preparing hydrazodicarbonamide using urea according to the present invention as a starting material is shown in general in Scheme 14, and an example of an apparatus for preparing hydrazodicarbonamide for carrying out this reaction is schematically shown in FIG. Shown.

As shown in FIG. 1, the apparatus for preparing hydrazodicarbonamide according to an embodiment of the present invention includes a pyrolysis furnace 10 for pyrolyzing urea to obtain burette and gaseous ammonia, and the pyrolysis furnace ( 10) is converted into an inert gas that does not react with air, nitrogen, or isocyanic acid inside the pyrolysis furnace 10 to increase the yield of the burette and at the same time reduce the amount of impurities. Gas injection means 12 for injecting inert gas, such as liquid organic matter, or decompression means (not shown) for removing ammonia from the pyrolysis furnace 10 by depressurizing the pyrolysis furnace 10 may be further provided. have.

The ammonia removed in the pyrolysis furnace 10 is preferably transferred to the ammonia concentrator 20, the ammonia concentrator 20 is surplus remaining after the production of ammonia and hydrazodicarbonamide transferred from the pyrolysis furnace 10 It functions to concentrate ammonia. The burette obtained in the pyrolysis furnace 10 is separated from impurities such as cyanuric acid and triuret by recrystallization means including a recrystallization reactor 30, a dehydrator 32 such as a centrifuge, and the like. Is transferred to.

The purified burette transferred to the first reactor 40 is converted into a monohalo burette metal salt by reaction with a metal hypohalogen compound such as NaOCl, or a halogen and a base such as Cl ₂ , and then transferred to the second reactor 50. . The monohaloburet metal salt transferred to the second reactor 50 is reacted with the concentrated ammonia sent from the ammonia concentrator 20 to be converted into the final product, hydrazodicarbonamide (HDCA), and with ammonia with an excess of ammonia. It is sent to the evaporator 52. The ammonia evaporator 52 evaporates the excess ammonia and transfers it to the ammonia concentrator 20, and the hydrazodicarbonamide separated from the excess ammonia is purified in a dehydrator 54 such as a filter.

As can be seen from the reaction scheme 13 and Figure 1, the method for producing hydrazodicarbonamide according to the present invention can be produced from the urea, the first raw material in a consistent process, hydrazodicarbonamide, by-products generated in the production of burette Hydrazodicarbonamide can be produced by reacting phosphorus ammonia with a monohaloburet metal salt, thereby minimizing the amount of raw material input and lowering the production cost, and improving the efficiency of the process by constructing the whole process continuously. In addition, hydrazodicarbonamide may be environmentally friendly by efficiently utilizing ammonia, which is an environmentally undesirable by-product.

Next, preferred preparation examples and examples are presented to aid in understanding the present invention. However, the following Preparation Examples and Examples are provided to more easily understand the present invention, and do not limit the present invention.

Production Example 1-4: Production of Burette

500 g (8.33 mol) of urea was put into a four neck round bottom flask, and air was inject | poured into the bottom of the flask at the injection speed of Table 1, stirring vigorously. At the same time, the flask was heated to maintain the reaction temperature at 140 ° C. for 5 hours. The components of the solids produced after the reaction was analyzed using liquid chromatography, and the results are shown in Table 1.

Production Example Air injection speed (L / min) Urea Content (% by weight) Burette content (% by weight) Cyanuric acid and other solids (% by weight) One 0 62 35 3 2 One 41 55 4 3 2 38 60 2 4 4 37 61 2

Production Example 5-7: Production of Burette

After fixing the air injection rate at 2 L / min, the burette was prepared in the same manner as in Preparation Example 1 except that the reaction was carried out for 3 hours while changing the reaction temperature. The components of the solids produced after the reaction was analyzed using liquid chromatography, and the results are shown in Table 2.

Production Example Reaction temperature (℃) Urea Content (% by weight) Burette content (% by weight) Cyanuric acid and other solids (% by weight) 5 150 47 50 3 6 160 38.5 57 4.3 7 170 28 65 7

Production Example 8-10: Production of Burette

A burette was manufactured in the same manner as in Preparation Example 1, except that the reaction was performed while reducing the pressure to the pressure shown in Table 3 using a vacuum pump instead of injecting air. The components of the solids produced after the reaction was analyzed using liquid chromatography, and the results are shown in Table 3.

Production Example Pressure (mmHg) Urea Content (% by weight) Burette content (% by weight) Cyanuric acid and other solids (% by weight) 8 380 56 50 4 9 190 41.5 55 3.5 10 100 40 57 3

Production Example 11-13: Production of Burette

A burette was prepared in the same manner as in Preparation Example 1, except that 0.05 mol of catalyst was used for urea, and the air injection rate was fixed at 2 L / min, followed by reaction. After completion of the reaction, the components of the solids produced were analyzed using liquid chromatography, and the results are shown in Table 4.

Production Example catalyst Urea Content (% by weight) Burette content (% by weight) Cyanuric acid and other solids (% by weight) 11 Sulfuric acid 34 62 4 12 Disodium phosphate 36 61 3 13 Thionyl chloride 35 62 3

Production Example 14 Synthesis of Chlorobutet Sodium Salt

In a 2 L glass reactor, 423.1 g (0.287 mole) of 7% biuret suspension solution was added and cooled to 5 ° C under stirring. 170 g (0.287 mol) of 12% aqueous sodium hypochlorite solution was added to the reactor, and the temperature of the reaction system was maintained at 5 ° C or lower. After the addition, the reaction solution was analyzed by iodine titration and liquid chromatography, and the effective chlorine was 3.37% (yield 98%).

Preparation Example 15 Synthesis of Chlorobutet Sodium Salt

In a 2 L glass reactor, 423.1 g (0.287 mole) of 7% biuret suspension solution was added and cooled to 5 ° C under stirring. 223 g (0.575 mol) of 10.3% sodium hydroxide aqueous solution was added to this reactor, and 20.3 g (0.287 mol) of chlorine gas were added, maintaining the temperature of the reaction solution at 10 degrees C or less. After the addition, the reaction solution was analyzed by iodine titration and liquid chromatography, and the effective chlorine of the reaction solution was 3.0% (yield 98%).

Preparation Example 16 Synthesis of Chlorobutet Sodium Salt

In a 2 L glass reactor, 423.1 g (0.287 mole) of 7% biuret suspension solution was added and cooled to 5 ° C under stirring. 20.3 g (0.287 mol) of chlorine gas was added while maintaining the temperature of the reaction solution at 10 ° C or lower. After the chlorine gas was added, 223 g (0.575 mol) of 10.3% aqueous sodium hydroxide solution was added while vigorously stirring the reaction solution, and the reaction temperature was maintained at 5 ° C or lower. After the addition, the reaction solution was analyzed by iodine titration and liquid chromatography, and the effective chlorine of the reaction solution was 3.0% (yield 98%).

Example 1-9 Synthesis of Hydrazodicarbonamide (HDCA)

593.1 g of a chloroburet sodium salt solution prepared according to Preparation Example 14 was placed in a 2 L pressure reactor and cooled to 10 ° C while stirring. While maintaining the temperature of the reaction solution below 10 ℃ was added 600g (8.8 mol) of 25% ammonia water, the reaction proceeded while changing the temperature and time of the reactor while vigorously stirring the reaction solution. After the completion of the reaction, unreacted ammonia was removed and the reaction solution was filtered to calculate the yield of HDCA that is insoluble in water.

Example Reaction condition (temperature, time) yield(%) One 30 ° C, 1 hour 85 2 30 ℃, 2 hours 90 3 30 ℃, 3 hours 89 4 60 ° C, 1 hour 91 5 60 ° C, 2 hours 89 6 60 ℃, 3 hours 90 7 90 ° C, 1 hour 88 8 90 ° C, 2 hours 89 9 90 ° C, 3 hours 90

Example 10-18 Synthesis of Hydrazodicarbonamide (HDCA)

The reaction was carried out in the same manner as in Example 4, except that 0.05 mol of the catalyst shown in Table 6 was added to the reaction system. After the completion of the reaction, unreacted ammonia was removed and the reaction solution was filtered to calculate the yield of HDCA that is insoluble in water.

Example Used catalyst yield(%) 10 ZnCl ₂ 94 11 Zn (OH) ₂ 92 12 AlCl ₃ 90 13 BaCl ₂ 91 14 CdCl ₂ 92 15 ZnSO ₄ 93 16 ZnCl ₂ + AlCl ₃ (0.025 mol each) 96 17 ZnCl ₂ + BaCl ₂ (0.025 mol each) 94 18 ZnCl ₂ + CdCl ₃ (0.025 mol each) 96

Example 19-27 Synthesis of Hydrazodicarbonamide (HDCA)

593.1 g of a chloroburet sodium salt solution prepared according to Preparation Example 15 was placed in a pressure reactor having a capacity of 2L and cooled to 10 ° C while stirring. While maintaining the temperature of the reaction solution below 10 ℃ 600g (8.8 mol) of 25% ammonia water was added, the reaction proceeded while changing the temperature and time of the reactor while vigorously stirring the reaction solution. After the completion of the reaction, unreacted ammonia was removed and the reaction solution was filtered to calculate the yield of HDCA that is insoluble in water.

Example Reaction condition (temperature, time) yield(%) 19 30 ° C, 1 hour 78 20 30 ℃, 2 hours 89 21 30 ℃, 3 hours 89 22 60 ° C, 1 hour 88 23 60 ° C, 2 hours 90 24 60 ℃, 3 hours 90 25 90 ° C, 1 hour 87 26 90 ° C, 2 hours 86 27 90 ° C, 3 hours 89

Example 28-36 Synthesis of Hydrazodicarbonamide (HDCA)

The reaction was carried out in the same manner as in Example 22, except that 0.05 mol of each of the catalysts shown in Table 8 was added to the reaction system. After the completion of the reaction, unreacted ammonia was removed and the reaction solution was filtered to calculate the yield of HDCA that is insoluble in water.

Example Used catalyst yield(%) 28 ZnCl ₂ 94 29 Zn (OH) ₂ 91 30 AlCl ₃ 89 31 BaCl ₂ 91 32 CdCl ₂ 93 33 ZnSO ₄ 92 34 ZnCl ₂ + AlCl ₃ (0.025 mol each) 97 35 ZnCl ₂ + BaCl ₂ (0.025 mol each) 93 36 ZnCl ₂ + CdCl ₃ (0.025 mol each) 96

Example 37-45: Synthesis of hydrazodicarbonamide (HDCA)

593.1 g of a chloroburet sodium salt solution prepared according to Preparation Example 16 was placed in a pressure reactor having a capacity of 2 L and cooled to 10 ° C while stirring. While maintaining the temperature of the reaction solution below 10 ℃ 600g (8.8 mol) 25% ammonia water was added, the reaction proceeded while changing the temperature and time of the reactor while vigorously stirring the reaction solution. After the completion of the reaction, unreacted ammonia was removed and the reaction solution was filtered to calculate the yield of HDCA that is insoluble in water.

Example Reaction condition (temperature, time) yield(%) 37 30 ° C, 1 hour 79 38 30 ℃, 2 hours 88 39 30 ℃, 3 hours 89 40 60 ° C, 1 hour 89 41 60 ° C, 2 hours 90 42 60 ℃, 3 hours 91 43 90 ° C, 1 hour 88 44 90 ° C, 2 hours 88 45 90 ° C, 3 hours 89

Example 46-54: Synthesis of hydrazodicarbonamide (HDCA)

The reaction was carried out in the same manner as in Example 40, except that 0.05 mol of each of the catalysts shown in Table 10 was added to the reaction system. After the completion of the reaction, unreacted ammonia was removed and the reaction solution was filtered to calculate the yield of HDCA that is insoluble in water.

Example Used catalyst yield(%) 46 ZnCl ₂ 93 47 Zn (OH) ₂ 90 48 AlCl ₃ 90 49 BaCl ₂ 90 50 CdCl ₂ 92 51 ZnSO ₄ 89 52 ZnCl ₂ + AlCl ₃ (0.025 mol each) 95 53 ZnCl ₂ + BaCl ₂ (0.025 mol each) 93 54 ZnCl ₂ + CdCl ₃ (0.025 mol each) 94

Example 55-58: Synthesis of Hydrazodicarbonamide (HDCA)

593.1 g of a chloroburet sodium salt solution prepared according to Preparation Example 14 was placed in a pressure reactor having a capacity of 2L and cooled to 10 ° C while stirring. While maintaining the temperature of the reaction solution at 10 ℃ or less while changing the amount of 25% ammonia water as shown in Table 11, the reaction was carried out for 1 hour at 60 ℃ while vigorously stirring the reaction solution. After the reaction was completed, unreacted ammonia was removed, and the reaction solution was filtered to calculate the yield of HDCA that is insoluble in water.

Example Ammonia Usage Ammonia / Chloro-Burette Sodium Salt yield(%) 55 15 75 56 30 87 57 60 90 58 90 89

Example 59-62 Synthesis of Hydrazodicarbonamide (HDCA)

593.1 g of a chloroburet sodium salt solution prepared according to Preparation Example 14 was added to a pressure reactor having a capacity of 2 L, and cooled to 10 ° C. while stirring, and various organic solvents were added 0.5 times compared to the weight of water as shown in Table 12 below. While maintaining the temperature of the reaction solution below 10 ℃ 600g (8.8 mol) 25% ammonia water was added, the reaction proceeded at 60 ℃ for 1 hour while vigorously stirring the reaction solution. After the reaction was completed, unreacted ammonia was removed, and the reaction solution was filtered to calculate the yield of HDCA that is insoluble in water.

Example Solvent used yield(%) 59 Methanol 90 60 Dimethylformamide 94 61 Tetrahydrofuran 90 62 Acetonitrile 88

As described above, the method and apparatus for preparing hydrazodicarbonamide according to the present invention can synthesize hydrazodicarbonamide economically and environmentally from starting materials which are inexpensive and easy to purchase, and by-products of Not only can the production and input of raw materials be minimized, but the entire process can be carried out continuously to produce hydrazodicarbonamide in high yield.

1 is a schematic diagram showing an example of an apparatus for producing hydrazodicarbonamide using urea as a starting material according to an embodiment of the present invention.

Claims (17)

Pyrolyzing urea to obtain a burette and ammonia of the formula (1); Reacting the obtained burette with a metal hypohalogen compound or a halogen and a base to obtain a monohaloburet metal salt of the following Chemical Formula 2 or 3; And Wherein the obtained monohaloburet metal salt and ammonia are reacted at a reaction molar ratio of 1: 1 to 1: 1000, wherein the ammonia reacted with the monohaloburet metal salt comprises ammonia produced by pyrolysis of the urea. process Hydrazodicarbonamide production method comprising a. [Formula 1] [Formula 2] [Formula 3] In Formulas 2 and 3, M represents a metal, and X represents a halogen. The method of claim 1, wherein the pyrolysis temperature of the urea is 100 to 300 ℃. The method for preparing hydrazodicarbonamide according to claim 1, wherein the pyrolysis of the urea is performed while removing ammonia from the reaction system. The method for preparing hydrazodicarbonamide according to claim 1, further comprising injecting an inert gas into the reactor and / or lowering the pressure of the reaction system during the pyrolysis of the urea. The method of claim 1, wherein the pyrolysis of the urea is carried out in the presence of at least one catalyst selected from the group consisting of inorganic acid catalysts, acidic catalysts, and phosphorus-containing materials. The method for producing hydrazodicarbonamide according to claim 1, wherein the molar ratio of the burette and the metal hypohalogen compound is from 1: 0.1 to 1: 2. The method of claim 1, wherein the monohalo burette metal salt is obtained by mixing the burette of Formula 1 with a metal hydroxide and then reacting with a halogen gas, or by reacting the burette with a halogen gas and then adding a base Method for preparing hydrazodicarbonamide. The method for preparing hydrazodicarbonamide according to claim 1, wherein the monohaloburet metal salt is obtained from the burette at 60 ° C or less. delete delete The method for producing hydrazodicarbonamide according to claim 1, wherein the ammonia is liquid ammonia, gas ammonia or ammonia hydrate. The method of claim 1, wherein the reaction of the monohaloburet metal salt with the ammonia is carried out at 0 to 150 ° C. The method of claim 1, wherein the reaction solvent of the monohaloburet metal salt and the ammonia is a polar solvent selected from the group consisting of water, methanol, ethanol, propanol, isopropanol and mixtures thereof, or dimethylformamide, dimethyl sulfoxide, A method for producing hydrazodicarbonamide, characterized in that water is mixed with a second solvent selected from aprotic solvents selected from the group consisting of dimethylacetamide, and mixtures thereof. Pyrolysis furnace to pyrolyze urea to obtain burette and ammonia; A recrystallization reactor for purifying the burette obtained in the pyrolysis furnace; A first reactor for reacting said recrystallized burette with a metal hypohalogen compound, or a halogen and a base, to obtain a monohalo burette metal salt; A second reactor for synthesizing hydrazodicarbonamide by reacting the monohaloburet metal salt obtained in the first reactor with ammonia; And In the manufacturing apparatus of the hydrazodicarbonamide including ammonia evaporator for separating the hydrazodicarbonamide and the excess amount of ammonia obtained in the second reactor, and transfers the separated ammonia to the ammonia concentrator, And the ammonia concentrator is configured to concentrate the excess amount of ammonia and the ammonia obtained in the pyrolysis furnace and to supply the ammonia to the second reactor. delete 15. The apparatus for producing hydrazodicarbonamide according to claim 14, wherein the pyrolysis furnace is further provided with gas injection means for injecting an inert gas that does not react with isocyanic acid into the pyrolysis furnace. 15. The apparatus for producing hydrazodicarbonamide according to claim 14, wherein the pyrolysis furnace is further equipped with decompression means for removing ammonia from the pyrolysis furnace by depressurizing the pyrolysis furnace.