JP4046722B2 - Method for producing hydrazine compound - Google Patents

Description

  The present invention relates to a method for producing a hydrazine compound using an electrolytic reaction.

Hydrazine and its derivatives are widely used as raw materials for medical pesticides and functional chemicals. For example, hydrazodicarbonamide (HDCA) is useful as a synthetic intermediate for azodicarbonamide (ADCA), which is useful as an industrial and food foaming agent.
Conventionally, as a method for producing HDCA, for example, a method in which hydrogenated hydrazine and urea are reacted by heating (see Patent Documents 1 and 2), urea is oxidized to chlorourea, Hoffmann transfer, and dehydration with water addition are performed. There is known a method of producing by reacting with urea without isolation after conversion to hydrazine by carbonic acid.

  Alternatively, urea can be oxidatively converted into chlorourea, converted to semicarbazide by Hoffmann transfer or ammonia addition (see Patent Document 3), and reacted with urea to convert it to HDCA without isolation.

  However, when the former hydrazine is reacted with urea, 2 mol of ammonia is generated for 1 mol of HDCA. In a situation where the amount of nitrogen released to the environment is regulated worldwide, the generated ammonia must be neutralized with an equivalent amount of acid such as hydrochloric acid or sulfuric acid and discharged as an ammonium salt. Also, in the latter method of obtaining HDCA from semicarbazide, in order to produce ammonia as a by-product at the time of conversion, a similar treatment or a method of recovering and reusing for the production process of semicarbazide must be adopted. Special equipment is required compared to the method.

  On the other hand, in order to obtain hydrazine using urea as a raw material, it can be produced by converting urea and chlorourea to transfer reaction and decarboxylation. However, sodium hypochlorite is used in the process of using urea as chlorourea, so that sodium chloride is used. Is a by-product in large quantities. When the salt concentration of wastewater is high, activated sludge used in wastewater treatment cannot be used. Therefore, sodium chloride must be collected and removed before wastewater treatment.

As described above, in any method, since a large amount of inorganic salt is by-produced, a step for removing it is necessary. Further, when considering environmental problems in the disposal of the removed inorganic salt, it is not an industrially excellent method.
JP 51-11719 US Pat. No. 2,692,281 Patent No. 2952712

  An object of the present invention is to provide an industrially superior production method that reduces the burden on the environment of a hydrazine compound that can be a useful industrial raw material without any by-product of inorganic salts.

The present invention relates to the following inventions.
1. A hydrazine hydrate (in the case of reaction in water) or a carbazate (in a lower alcohol ) , characterized by applying an electrolysis reaction to urea in the absence of urease in water or in a lower alcohol having 1 to 4 carbon atoms. In the case of reaction) .
2. A method for producing a carbazic acid ester, wherein an electrolytic reaction is applied to urea in a lower alcohol having 1 to 4 carbon atoms .
3. A hydrazodicarboxylic acid characterized by heating a carbazate obtained by applying an electrolytic reaction to urea in the absence of urease in a lower alcohol having 1 to 4 carbon atoms, in the presence of urea and an acid. Method for producing amide.
4). It is characterized by applying an electrolysis reaction to urea in a lower alcohol having 1 to 4 carbon atoms in the absence of urease so that the conversion rate to carbazate is 40 to 60%, and then adding an acid and heating. A method for producing hydrazodicarbonamide.
5. A method for producing a hydrazodicarbonamide represented by the formula (5), wherein the carbazate represented by the formula (4) is heated in the presence of urea and an acid.

（Ｒは炭素数１〜４のアルキル基を示す。）

(R represents an alkyl group having 1 to 4 carbon atoms.)

6). A method for producing a hydrated hydrazine, characterized by applying an electrolytic reaction to urea in the absence of urease in water.

  As a result of various studies, the present inventors have found a simple and efficient production method of hydrated hydrazine, carbazate, and HDCA, and further has an extremely low environmental load.

  According to the production method of the present invention, the target product can be obtained very efficiently without the by-product of inorganic salts such as sodium chloride and ammonia in the production of hydrated hydrazine, carbazate, and HDCA. Is extremely advantageous.

  In addition, in the method for producing HDCA by reacting urea with the carbazic acid ester of the present invention in the presence of an acid, the carbazic acid ester and urea react at a molar ratio of 1: 1, and the resulting ammonia generates HDCA. Therefore, it has an industrially advantageous feature that ammonia is apparently not by-produced.

  The method for producing a hydrazine compound of the present invention is represented by the following reaction formula.

［式中、Ｒは炭素数１〜４の低級アルキル基を示す。］

[Wherein, R represents a lower alkyl group having 1 to 4 carbon atoms. ]

According to the reaction formula , the urea represented by the formula (1) is subjected to an electrolytic reaction in water or a lower alcohol, thereby passing through the isocyanate derivative represented by the formula (2) and represented by the formula (3). The hydrated hydrazine or carbazate represented by the formula (4) is produced. Furthermore, HDCA represented by the formula (5) is produced from the carbazic acid ester represented by the formula (4).

  The production method of the present invention applies an electrolytic reaction to urea. The electrode material used for the electrolytic reaction is not particularly limited as long as it is an electrode material used for general electrolytic reaction. For example, the anode is titanium, platinum, carbon, lead oxide, nickel, iron, stainless steel, lead. In consideration of economic efficiency and reaction efficiency, such as composite materials or laminates thereof, and cathodes such as titanium, platinum, carbon, lead oxide, nickel, iron, stainless steel, lead, and composite materials or laminates thereof. It is preferable to select as appropriate.

Examples of the lower alcohol used in this reaction include C1-C4 lower alcohols such as methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, and tert-butanol. These lower alcohols can be used singly or in combination of two or more.
In the production method of the present invention, a hydrazine compound to be produced can be selected by selecting either water or a lower alcohol.

When the target hydrazine compound is hydrated hydrazine, it can be produced by using water.
When the target hydrazine compound is a carbazate, it can be produced by using a lower alcohol corresponding to the alkoxy group of the ester part. In the case of methyl carbazate, methanol, and in the case of ethyl carbazate, ethal Can be achieved by using In the production of the carbazate, methanol or ethanol is preferable in consideration of urea solubility and reaction efficiency, and methanol is particularly preferable.

The amount of water or lower alcohol used is preferably appropriately selected in consideration of economy, reaction efficiency, and solubility of the reaction substrate. For example, 0.1 to 15.0 L, preferably 1 What is necessary is just to use in the range of 0.0-10.0L. These waters or lower alcohols are involved in the reaction but also function as solvents.
Further, other organic solvents may be used as necessary, and any organic solvent can be used as long as it does not adversely affect the present electrolysis reaction.

In this electrolytic reaction, it is preferable to use a supporting electrolyte. The supporting electrolyte is not particularly limited as long as it is a supporting electrolyte used in a general electrolytic reaction. For example, lithium chloride, sodium chloride, potassium chloride, lithium bromide, sodium bromide, potassium bromide, lithium iodide, iodine Examples thereof include potassium iodide, sodium iodide, lithium fluoride, sodium fluoride, potassium fluoride, and sodium chloride is preferable in consideration of economy and environmental aspects.
The amount of the supporting electrolyte used may be, for example, about 0.001 to 1 equivalent, preferably about 0.01 to 0.5 equivalent, with respect to 1 mole of urea. It is preferable to select appropriately in consideration of reaction efficiency and economy.

The supporting electrolyte used in the electrolytic reaction can be recovered by a process such as filtration and can be reused.
The electrolytic reaction is preferably basically performed using a non-diaphragm device, but a diaphragm or an ion exchange membrane can be used depending on conditions.

The current density may be appropriately selected within the range of 1 to 200 mA / cm ² , preferably 10 to 100 mA / cm ² , and more preferably 20 to 80 mA / cm ² . Current density decreases reaction efficiency is less than 1 mA / cm ^2, also selectivity of the reaction to exceed 200 mA / cm ² is significantly reduced.
The energization amount is appropriately selected within a range of 01 F / mol or more, preferably 0.1 to 50 F / mol, more preferably 0.5 to 40 F / mol, and still more preferably 0.8 to 30 F / mol per 1 mol of urea. do it. This electrolytic reaction is a two-electron oxidation reaction. Theoretically, the total amount of urea is converted at 2 F / mol with respect to 1 mol of urea, and the half amount of urea is converted at 1 F / mol. Therefore, it is preferable to bring the energization amount close to the theoretical amount by appropriately setting the conditions in consideration of energy efficiency.

The applied voltage is preferably selected in the range of 1 to 30 V, preferably 1 to 20 V, more preferably 1.5 to 15 V, depending on the amount of the supporting electrolyte used, the apparatus, and other conditions.
The reaction temperature of the electrolytic reaction is not particularly limited as long as it is equal to or lower than the boiling point of the water or lower alcohol used, and is characterized in that the reaction proceeds at about room temperature, for example, 0 to 40 ° C, preferably 20 to 30 ° C. In the range, it is preferable to select appropriately according to the solubility of urea.

  In the present electrolytic reaction, the conversion ratio to the target product can be controlled by appropriately setting the type of supporting electrolyte, the type of electrode, the current density, the amount of energization, the temperature, and other conditions. For example, under conditions where the supporting electrolyte is sodium chloride, the electrode is a platinum electrode, the current density is about 50 mA, and the room temperature is about 10 F / mol or more, the reaction can be completed almost uniformly. By setting the energization amount to about 5 to 7 F / mol, the conversion rate can be set to 40 to 60%.

Next, HDCA can be easily produced by reacting carbazic acid ester obtained by electrolytic reaction with urea in the presence of an acid.
In this reaction, the amount of urea used is about 0.5 to 2 moles, preferably about 0.8 to 1.5 moles, more preferably 1.0 to 1.2 moles per mole of carbazate. It should be about.

This reaction is carried out in a suitable solvent. As the solvent, water is usually most preferable, but water-containing methanol, water-containing ethanol, water-containing tetrahydrofuran, water-containing dioxane and the like may be appropriately selected in consideration of the solubility of the substrate in water.
The amount of the solvent used may be such that the urea concentration is 0.1 to 10 mol / L, more preferably 1 to 5 mol / L.

  Examples of the acid used in this reaction include inorganic acids such as sulfuric acid, hydrochloric acid, and phosphoric acid, phosphotungstic acid, phosphomolybdic acid, phosphomolybdotungstic acid, phosphomolybdovanadic acid, silicotungstic acid, and silicomolybdic acid. Examples include heteropolyacids, strongly acidic ion exchange resins, organic acids such as oxalic acid, and solid acids such as aluminosilicate. These may be used alone or in combination of two or more depending on the purpose. it can.

The amount of acid used is usually about 0.01 to 1 mol, more preferably about 0.05 to 0.5 mol, per mol of carbazic acid ester.
When the amount used is less than 0.01 mol with respect to 1 mol of the carbazic acid derivative, the reaction rate decreases rapidly, and when it exceeds 1 mol, the reaction selectivity decreases and the yield of the target product decreases.

The reaction temperature is usually from 10 ° C. to the boiling point of the solvent used, but it is preferable to reflux the solvent at a temperature equal to or higher than the boiling point for the purpose of increasing the reaction rate.
The reaction time varies depending on the type of carbazate and the reaction temperature, but is usually completed in about 3 to 30 hours.

The HDCA produced by this method can be isolated by conventional isolation means such as filtration, solvent extraction, recrystallization and the like.
In addition, the carbazic acid ester used in this reaction may be used by isolating the one obtained by the electrolytic reaction, but in the electrolytic reaction, the type of supporting electrolyte, the type of electrode, the current density, the amount of energization, The conversion rate to carbazate is controlled by appropriately setting the temperature and other conditions, and approximately 40 to 60%, preferably about half the conversion rate, urea and carbazate are present in approximately equal amounts in the reaction system. Can be prepared and used. In this case, since urea and carbazate existing in the reaction system react to produce HDCA, it is not necessary to add urea again, and the acid can be added to the filtrate obtained by filtering the electrolytic reaction solution as it is or by filtration. This reaction solution may be used, or a solvent and an acid may be added again to the residue obtained by removing the solvent from the electrolytic reaction solution, and this reaction solution may be used.

  In this reaction, the carbazate and urea react at a molar ratio of 1: 1, and the resulting ammonia is consumed for the production of HDCA. ing.

  Hereinafter, the present invention will be described by way of examples. However, the present invention is not limited to the examples.

Example 1 (Production of methyl carbamate)
Dissolve 1.2 g (20 mmol) of urea in 50 ml of methanol, add 0.30 g (5.2 mmol) of sodium chloride, and then use a platinum electrode (20 mm long x 10 mm wide) for both the anode and cathode (capacitor) 100 cc), a current of 10 F / mol was passed (current density 50 mA / cm ² , applied voltage 10 to 15 V, about 25 ° C.). Methanol was removed from the reaction mixture under reduced pressure, and 10 ml of methylene chloride was added to the resulting residue. Insoluble matter was removed by filtration, and the solvent of the mother liquor was removed under reduced pressure to obtain 1.71 g of crude methyl carbamate as pale yellow crystals (95% yield from Urea).
When the purity was confirmed using the following high performance liquid chromatography, it was 98.5%, and thus the yield was 93.6% (from Area).
<High performance liquid chromatography conditions>
Column: ODS A-303 (manufactured by YMC)
Detection wavelength (UV): 225 nm
Mobile phase: acetonitrile / water = 5/95
Flow rate: 0.8 ml / min
Column oven temperature: 40 ° C

Example 2 (Production of methyl carbamate)
Except for replacing sodium chloride with potassium bromide, the same procedure as in Example 1 was carried out to obtain methyl carbadate in a yield of 90.1%.

Example 3 (Production of methyl carbamate)
The same procedure as in Example 1 was carried out except that the amount of current was 20 F / mol, and methyl carbadate was obtained in a yield of 92.2%.

Example 4 (Production of ethyl carbamate)
Except for changing the methanol to ethanol, the same procedure as in the production of methyl carbamate in Example 1 was carried out to obtain ethyl carbazate in a yield of 92.8%.

Example 5 (Production of HDCA)
To 1.71 g (18.7 mmol) of methyl carbamate prepared in Example 1, 1.12 g (18.9 mmol) of urea, 10 ml of water and 0.552 g (5.5 mmol) of concentrated sulfuric acid (98%) were added, and oil was added. Refluxed using a bath for 30 hours. The reaction mixture was cooled to room temperature, and the precipitated white crystals were filtered off. The crystals were washed with water and dried at 110 ° C. for 24 hours to obtain 1.21 g of HDCA.
The obtained crystal was judged to be HDCA because it was completely consistent with the standard in the IR spectrum. Further, when the purity was confirmed by using the following high performance liquid chromatography, it was 95.2%, and thus the yield was 95.2% (from methyl carbamate).
Melting point: 248-252 ° C
IR (KBr method): 3390 cm ⁻¹ (ν-CONH ₂ ), 3205 cm ⁻¹ (ν-CONH—), 1672 (ν-CO—)
<High performance liquid chromatography conditions>
Column: Inertsil ODS-3 (GL Sciences)
Detection wavelength (UV): 205 nm
Mobile phase: Na ₂ HPO ₄ / KH ₂ PO ₄ (18 mmol / 9 mmol) Water / methanol = 96/4
Flow rate: 0.5 ml / min
Column oven temperature: 30 ° C

Example 6 (Production of HDCA)
Dissolve 1.2 g (20 mmol) of urea in 50 ml of methanol, add 0.30 g (5.2 mmol) of sodium chloride, and then use a platinum electrode (20 mm long × 10 mm wide) for both the anode and cathode (capacitor) 100 cc), a current of 6.7 F / mol was passed (current density 50 mA / cm ² , applied voltage 10 to 15 V, about 25 ° C.). It was confirmed by high performance liquid chromatography that the reaction mixture contained 9.4 mmol (conversion rate: about 47%) of methyl carbamate.
Methanol was removed from the reaction mixture under reduced pressure, 10 ml of water and 0.276 g (2.8 mmol) of concentrated sulfuric acid (98%) were added, and the mixture was refluxed for 4 hours using an oil bath. The reaction mixture was cooled to room temperature, and the precipitated white crystals were filtered off. The crystals were washed with water and dried at 110 ° C. for 24 hours to obtain 1.09 g of HDCA (92% yield from Urea).
The obtained crystal was determined to be hydrazodicarbonamide because it was completely in agreement with the sample in the IR spectrum. Further, when the purity was confirmed by using high performance liquid chromatography, it was 99.0%, so that the yield was 91.1% (from Area).

Example 7 (Production of HDCA)
Dissolve 1.2 g (20 mmol) of urea in 50 ml of methanol, add 0.30 g (5.2 mmol) of sodium chloride, and then use a platinum electrode (20 mm long × 10 mm wide) for both the anode and cathode (capacitor) 100 cc), a current of 3.4 F / mol was passed (current density 70 mA / cm ² , applied voltage 2.1 to 2.3 V, about 22 ° C.). It was confirmed by high performance liquid chromatography that the reaction mixture contained 9.5 mmol of methyl carbamate.
Methanol was removed from the reaction mixture under reduced pressure, 10 ml of water and 0.276 g (2.8 mmol) of concentrated sulfuric acid (98%) were added, and the mixture was refluxed for 4 hours using an oil bath. The reaction mixture was cooled to room temperature, and the precipitated white crystals were filtered off, washed with water and dried at 110 ° C. for 24 hours to obtain 1.10 g of HDCA (93% yield from Urea).
The obtained crystal was determined to be hydrazodicarbonamide because it was completely in agreement with the sample in the IR spectrum. Further, when the purity was confirmed by using high performance liquid chromatography, it was 98.2%, so that the yield was 91.3% (from Urea).

Example 8 (Production of hydrated hydrazine)
After 1.2 g (20 mmol) of urea was dissolved in 100 ml of distilled water and 0.30 g (5.2 mmol) of sodium chloride was added, a diaphragm apparatus using a platinum electrode (vertical 20 mm × width 10 mm) for both the anode and the cathode ( A current of 10 F / mol was passed at a capacity of 100 cc) (current density 50 mA / cm ² , applied voltage 10 to 15 V, about 25 ° C.). 0.2 g of the reaction solution was collected and diluted to 30 ml with deionized water. Next, after acidifying with 6N hydrochloric acid, about 3 ml of chloroform was added and potassium iodate titration was performed, and the yield of the obtained hydrated hydrazine was calculated to be 65%.

Claims (8)

A hydrazine hydrate (in the case of reaction in water) or a carbazate (in a lower alcohol ) , characterized by applying an electrolysis reaction to urea in the absence of urease in water or in a lower alcohol having 1 to 4 carbon atoms. In the case of reaction) . A method for producing a carbazic acid ester, wherein an electrolytic reaction is applied to urea in a lower alcohol having 1 to 4 carbon atoms . The method of claim 2, wherein performing electrolytic reaction at a current density 1~200mA / cm ^2. A hydrazodicarboxylic acid characterized by heating a carbazate obtained by applying an electrolytic reaction to urea in the absence of urease in a lower alcohol having 1 to 4 carbon atoms, in the presence of urea and an acid. Method for producing amide. It is characterized by applying an electrolysis reaction to urea in a lower alcohol having 1 to 4 carbon atoms in the absence of urease so that the conversion rate to carbazate is 40 to 60%, and then adding an acid and heating. A method for producing hydrazodicarbonamide. A method for producing a hydrazodicarbonamide represented by the formula (5), wherein the carbazate represented by the formula (4) is heated in the presence of urea and an acid.

(R represents an alkyl group having 1 to 4 carbon atoms.)

A method for producing a hydrated hydrazine, characterized by applying an electrolytic reaction to urea in the absence of urease in water. The production method according to claim 7, wherein the electrolytic reaction is performed at a current density of 1 to 200 mA / cm ² .