Synthesis method of phenylhydrazine hydrochloride

Abstract

The present application discloses a method for synthesizing phenylhydrazine hydrochloride, comprising the following steps: Step 1): aniline, ethanolic hydrochloric acid solution, and NaNO2 solution are stirred at 0-5°C, and a diazotization reaction occurs to obtain a reaction solution containing aniline diazonium salt; Step 2): a catalyst and NH4HSO3 solution are added to the reaction solution containing aniline diazonium salt obtained in step 1), and a reduction reaction occurs at 30-40°C, and the reaction solution containing diazonium benzene disulfonic acid amine is filtered; Step 3): ethanolic hydrochloric acid solution is added to the reaction solution containing diazonium benzene disulfonic acid amine prepared in step 2), and the reaction is carried out at 70-80°C, the temperature is lowered, crystallization is performed, and centrifugation is performed to obtain the phenylhydrazine hydrochloride. In the method for synthesizing phenylhydrazine hydrochloride of the present invention, the yield of phenylhydrazine hydrochloride is high and the purity is high.

Description

Technical Field

[0001] The present application relates to the technical field of organic chemistry, and in particular to a method for synthesizing phenylhydrazine hydrochloride. Background Art

[0002] Phenylhydrazine is an important fine chemical intermediate with a wide range of uses in industry. In pesticide production, it is used to synthesize the intermediate 1-phenylaminourea of ​​the organophosphorus insecticide triazophos and the intermediate 1-phenyl-3,6-dihydroxypyridazine of pyridazinon. It is also an intermediate of the new fungicide varieties famoxadone and fenamidone. In addition, as an organic synthesis raw material, phenylhydrazine is also used as an intermediate in the dye, pharmaceutical and other industries, and is also used as an analytical reagent. Therefore, the synthesis of phenylhydrazine plays an important role in industrial production.

[0003] In the prior art, there are many methods for synthesizing phenylhydrazine. At present, the industrial method for synthesizing phenylhydrazine mainly uses aniline, a diazotizing agent, a reducing agent and an acid as raw materials, and sequentially undergoes three steps of diazotization, reduction and acidolysis to obtain a phenylhydrazine salt.

[0004] The reducing agents used more frequently in the prior art are stannous chloride, sodium sulfite, zinc powder, ammonium sulfite, sodium bisulfite and ammonium bisulfite. Among them, the reduction method of zinc powder and stannous chloride is mainly used for laboratory preparation and has no industrial significance. A large amount of water is used as a solvent in the reduction reaction of sulfite or bisulfite, and the wastewater discharge is large. In addition, there are many disadvantages such as long reaction time, low reaction efficiency, and many by-products, resulting in low purity and low yield of the product after acid hydrolysis and salt formation. In the preparation process, an additional purification step needs to be added to obtain a phenylhydrazine salt with higher purity. Although the purity of the product after purification can reach more than 98%, this further reduces the product yield and increases the cost.

[0005] Therefore, it is necessary to provide a method for synthesizing a phenylhydrazine salt with high reaction efficiency, high yield and high purity. Summary of the invention

[0006] The present invention aims to solve at least one of the problems of the prior art. Thus, the present invention provides a method for synthesizing phenylhydrazine hydrochloride, comprising the following steps:

[0007] Step 1): Aniline, ethanolic hydrochloric acid solution, NaNO 2 The solution is stirred at 0-5°C to cause a diazotization reaction to obtain a reaction solution containing aniline diazonium salt;

[0008] Step 2): Add catalyst, NH 4HSO 3 The solution is subjected to a reduction reaction at 30-40°C and filtered to obtain a reaction solution containing diazobenzenedisulfonic acid amine; the catalyst is CaCl 2 , a mixture consisting of zeolite molecular sieves;

[0009] Step 3): Adding hydrochloric acid ethanol solution to the reaction solution containing diazobenzenedisulfonic acid amine prepared in step 2), reacting at 70-80° C., cooling, crystallizing, and centrifuging to obtain the phenylhydrazine hydrochloride.

[0010] The structural formula of phenylhydrazine hydrochloride is shown below:

[0011] .

[0012] Hydrochloric acid ethanol solution refers to a solution formed after hydrogen chloride is dissolved in ethanol. It is a commonly used solution in laboratories and industries, has high safety, and is commercially available with hydrochloric acid ethanol solutions of different concentrations, which are easy to obtain. The present invention replaces the aqueous hydrochloric acid solution with hydrochloric acid ethanol solution, adds a catalyst during the reduction process, adjusts the preparation process, and finally, the yield of phenylhydrazine hydrochloride is improved, and the purity is improved. The yield is calculated based on the raw material aniline, and the yield can reach more than 85%, even more than 90%, more than 95%. The purity can reach more than 90%, even more than 95%, more than 99%.

[0013] Furthermore, in step 1), the concentration of the hydrochloric acid ethanol solution is 25-40wt%, preferably 30-40wt%.

[0014] In a specific embodiment, in step 1), the concentration of the hydrochloric acid ethanol solution may be 25-30wt%, 30-35wt%, 35-40wt%, 25-35wt%, 30-40wt%.

[0015] In a specific embodiment, in step 1), the concentration of the hydrochloric acid ethanol solution can be 25wt%, 30wt%, 35wt%, or 40wt%.

[0016] Furthermore, in step 1), the NaNO 2 The concentration of the solution is 1.8-3 mol / L, preferably 2-3 mol / L.

[0017] In a specific embodiment, in step 1), the NaNO 2 The concentration of the solution can be 1.8-2 mol / L, 2-2.5 mol / L, or 2.5-3 mol / L.

[0018] In a specific embodiment, in step 1), the NaNO 2The concentration of the solution can be 1.8 mol / L, 2 mol / L, 2.5 mol / L, or 3 mol / L.

[0019] Furthermore, in step 1), aniline, hydrochloric acid, NaNO 2 The molar ratio is 1:(2.3-2.8):(1.1-1.5).

[0020] In a specific embodiment, in step 1), aniline, hydrochloric acid, NaNO 2 The molar ratio can be 1:(2.3-2.6):(1.1-1.2), 1:(2.3-2.6):(1.2-1.5), 1:(2.6-2.8):(1.1-1.2), 1:(2.6-2.8):(1.2-1.5).

[0021] In a specific embodiment, in step 1), aniline, hydrochloric acid, NaNO 2 The molar ratio can be 1:2.6:1.2, 1:2.8:1.5, 1:2.3:1.1.

[0022] Furthermore, in the step 1), the stirring speed is controlled to be 160-260 r / min, preferably 180-260 r / min.

[0023] In a specific embodiment, in step 1), the stirring speed is controlled to be 160-180 r / min, 180-220 r / min, or 220-260 r / min.

[0024] In a specific embodiment, in step 1), the stirring speed is controlled to be 160 r / min, 180 r / min, 220 r / min, or 260 r / min.

[0025] Furthermore, in step 2), NH 4 HSO 3 The concentration of the solution is 50-60wt%, NH 4 HSO 3 The molar ratio of aniline to step 1) is (2.5-2.8):1.

[0026] In a specific embodiment, in step 2), NH 4 HSO 3 The concentration of the solution may be 50-54wt%, 54-60wt%.

[0027] In a specific embodiment, in step 2), NH 4 HSO 3The concentration of the solution may be 50wt%, 54wt%, or 60wt%.

[0028] In a specific embodiment, in step 2), NH 4 HSO 3 The molar ratio of the aniline in step 1) can be (2.5-2.6):1, (2.6-2.8):1.

[0029] In a specific embodiment, in step 2), NH 4 HSO 3 The molar ratio of aniline to the step 1) can be 2.5:1, 2.6:1, or 2.8:1.

[0030] Furthermore, in the step 2), the mass molar ratio of the catalyst to the aniline in the step 1) is 18-30 g:1 mol, preferably 20-30 g:1 mol.

[0031] In a specific embodiment, in step 2), the mass molar ratio of the catalyst to the aniline in step 1) can be 18-20 g: 1 mol, 20-25 g: 1 mol, or 25-30 g: 1 mol.

[0032] In a specific embodiment, in step 2), the mass molar ratio of the catalyst to the aniline in step 1) can be 18 g: 1 mol, 20 g: 1 mol, 25 g: 1 mol, or 30 g: 1 mol.

[0033] Furthermore, in step 2), the catalyst CaCl 2 The mass ratio of the zeolite molecular sieve is (1-5):1, preferably (2-5):1.

[0034] In a specific embodiment, in step 2), the catalyst CaCl 2 The mass ratio of the zeolite molecular sieve can be (1-2):1, (2-3):1, (3-5):1.

[0035] In a specific embodiment, in step 2), the catalyst CaCl 2 The mass ratio to the zeolite molecular sieve can be 1:1, 2:1, 3:1, or 5:1.

[0036] Furthermore, in step 3), the concentration of the hydrochloric acid ethanol solution is 25-40wt%, preferably 30-40wt%, and the molar ratio of hydrochloric acid to aniline in step 1) is (2.5-2.8):1.

[0037] In a specific embodiment, in step 3), the concentration of the hydrochloric acid ethanol solution can be 25-30wt%, 30-35wt%, or 35-40wt%.

[0038] In a specific embodiment, in step 3), the concentration of the hydrochloric acid ethanol solution can be 25wt%, 30wt%, 35wt%, or 40wt%.

[0039] In a specific embodiment, in step 3), the molar ratio of hydrochloric acid to aniline in step 1) can be (4.5-4.6):1, (4.6-4.8):1.

[0040] In a specific embodiment, in step 3), the molar ratio of hydrochloric acid to aniline in step 1) can be 4.5:1, 4.6:1, or 4.8:1.

[0041] Furthermore, in step 3), the temperature is lowered to 15-30°C, preferably 20-30°C.

[0042] In a specific embodiment, in step 3), the temperature is lowered to 15-20°C, 20-25°C, or 25-30°C.

[0043] In a specific embodiment, in step 3), the temperature is lowered to 15°C, 20°C, 25°C, or 30°C.

[0044] In summary, the beneficial technical effects of this application are:

[0045] 1. In the synthesis method of phenylhydrazine hydrochloride of the present invention, ethanol hydrochloric acid solution is used instead of aqueous hydrochloric acid solution in the diazotization reaction and acidolysis salt-forming steps, and a catalyst is added in the reduction step, thereby improving the yield and purity of phenylhydrazine hydrochloride, and ethanol can be recycled, thereby reducing the amount of waste water and reducing costs.

[0046] 2. In the synthesis method of phenylhydrazine hydrochloride of the present invention, the yield of phenylhydrazine hydrochloride is as high as over 95%, and the purity is over 95%, even over 97%, even over 99.5%.

[0047] 3. In the synthesis method of phenylhydrazine hydrochloride of the present invention, no special reactor, such as a continuous flow reactor, is used, and there is no special requirement for the equipment. The reaction equipment is simple and easy to industrialize. DETAILED DESCRIPTION

[0048] The present invention will be further described below in conjunction with specific examples, but the following examples are only used to illustrate the present invention and should not be considered to limit the scope of the present invention. In the following examples, if specific conditions are not specified, they are carried out according to conventional conditions or conditions recommended by the manufacturer. The methods used are conventional methods known in the art unless otherwise specified, and the consumables and reagents used are commercially available unless otherwise specified. Unless otherwise specified, the professional and scientific terms used herein have the same meaning as those familiar to those skilled in the art. In addition, any method or material similar or equal to the recorded content may also be applied to the present invention. In the following examples, the zeolite molecular sieve used is molecular sieve ZSM-35, purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.

[0049] The present invention provides a method for synthesizing phenylhydrazine hydrochloride, comprising the following steps:

[0050] Step 1): Aniline, ethanolic hydrochloric acid solution, NaNO 2 The solution is stirred at 0-5°C to cause a diazotization reaction to obtain a reaction solution containing aniline diazonium salt;

[0051] Step 2): Add catalyst, NH 4 HSO 3 The solution is subjected to a reduction reaction at 30-40°C and filtered to obtain a reaction solution containing diazobenzenedisulfonic acid amine; the catalyst is CaCl 2 , a mixture consisting of zeolite molecular sieves;

[0052] Step 3): Adding hydrochloric acid ethanol solution to the reaction solution containing diazobenzenedisulfonic acid amine prepared in step 2), reacting at 70-80° C., cooling, crystallizing, and centrifuging to obtain the phenylhydrazine hydrochloride.

[0053] Preferably, in step 1), the concentration of the hydrochloric acid ethanol solution is 25-40wt%.

[0054] Preferably, in step 1), the NaNO 2 The concentration of the solution is 1.8-3 mol / L.

[0055] Preferably, in step 1), aniline, hydrochloric acid, NaNO 2 The molar ratio is 1:(2.3-2.8):(1.1-1.5).

[0056] Preferably, in step 1), the stirring speed is controlled to be 160-260 r / min.

[0057] Preferably, in step 1), the reaction time is 1-1.5 h.

[0058] Preferably, in step 2), NH 4 HSO 3 The concentration of the solution is 50-60wt%, NH 4 HSO 3 The molar ratio of aniline to step 1) is (2.5-2.8):1.

[0059] Preferably, in step 2), the mass molar ratio of the catalyst to the aniline in step 1) is 18-30 g:1 mol.

[0060] Preferably, in step 2), the catalyst contains CaCl 2 The mass ratio to zeolite molecular sieve is (1-5):1.

[0061] Preferably, in step 2), the reaction time is 3-4 hours.

[0062] Preferably, in step 3), the concentration of the hydrochloric acid ethanol solution is 25-40wt%, and the molar ratio of hydrochloric acid to aniline in step 1) is (4.5-4.8):1.

[0063] Preferably, in step 3), the temperature is lowered to 15-30°C.

[0064] Preferably, in step 3), the reaction time is 1.5-2.5 h.

[0065] The present invention is further described below by means of Examples 1-10 and Comparative Examples 1-5.

[0066] Example 1

[0067] A method for synthesizing phenylhydrazine hydrochloride comprises the following steps:

[0068] Step 1): Aniline (1 mol, 93.1 g), hydrochloric acid ethanol solution (the concentration of hydrochloric acid ethanol solution is 33 wt%, the amount of hydrochloric acid is 2.6 mol), NaNO 2 Aqueous solution (NaNO 2 The concentration of NaNO is 2.5 mol / L. 2 The amount is 1.2 mol) at 2°C, stirred, and the stirring speed is controlled to 220r / min, and a diazotization reaction occurs. The reaction time is controlled to 1.5h to obtain a reaction solution containing aniline diazonium salt; the reaction formula is as follows:

[0069]

[0070] Step 2): Add 25 g of catalyst (the catalyst is 18.75 g of CaCl 2, a mixture of 6.25 g of zeolite molecular sieve), NH 4 HSO 3 Solution (NH 4 HSO 3 The concentration of NH 4 HSO 3 The amount is 2.6 mol), and a reduction reaction occurs at 35°C. The reaction time is controlled to be 3.5 h. The reaction solution containing diazobenzenedisulfonic acid amine is obtained by filtration. The reaction formula is as follows:

[0071]

[0072] Step 3): Add hydrochloric acid ethanol solution (the concentration of hydrochloric acid ethanol solution is 33wt%, the amount of hydrochloric acid is 4.6mol) to the reaction solution containing diazobenzenedisulfonic acid amine prepared in step 2), react at 75°C, control the reaction time to 2h, cool to 25°C, crystallize, centrifuge, and obtain phenylhydrazine hydrochloride. The reaction formula is as follows:

[0073] ;

[0074] ;

[0075] The yield of phenylhydrazine hydrochloride was calculated based on aniline in step 1), and the yield of phenylhydrazine hydrochloride was 96.8% and the purity was 99.8%.

[0076] Example 2

[0077] A method for synthesizing phenylhydrazine hydrochloride comprises the following steps:

[0078] Step 1): Aniline (1 mol, 93.1 g), hydrochloric acid ethanol solution (the concentration of hydrochloric acid ethanol solution is 30 wt%, the amount of hydrochloric acid is 2.8 mol), NaNO 2 Aqueous solution (NaNO 2 The concentration of NaNO is 2 mol / L. 2 The amount is 1.5 mol) at 0°C, stirred, and the stirring speed is controlled to 180r / min, and a diazotization reaction occurs. The reaction time is controlled to 1h to obtain a reaction solution containing aniline diazonium salt; the reaction formula is as follows:

[0079]

[0080] Step 2): Add 20 g of catalyst (the catalyst is 13.33 g of CaCl 2 , a mixture of 6.67 g of zeolite molecular sieve), NH 4 HSO3 Solution (NH 4 HSO 3 The concentration of NH 4 HSO 3 The amount is 2.5 mol), and a reduction reaction occurs at 30°C. The reaction time is controlled to be 3 hours. The reaction solution containing diazobenzenedisulfonic acid amine is filtered to obtain the reaction solution. The reaction formula is as follows:

[0081]

[0082] Step 3): Add hydrochloric acid ethanol solution (the concentration of hydrochloric acid ethanol solution is 40wt%, the amount of hydrochloric acid is 4.5mol) to the reaction solution containing diazobenzenedisulfonic acid amine prepared in step 2), react at 70°C, control the reaction time to 2.5h, cool to 20°C, crystallize, centrifuge, and obtain phenylhydrazine hydrochloride. The reaction formula is as follows:

[0083] ;

[0084] ;

[0085] The yield of phenylhydrazine hydrochloride was calculated based on aniline in step 1), and the yield of phenylhydrazine hydrochloride was 95.6% and the purity was 99.6%.

[0086] Example 3

[0087] A method for synthesizing phenylhydrazine hydrochloride comprises the following steps:

[0088] Step 1): Aniline (1 mol, 93.1 g), hydrochloric acid ethanol solution (the concentration of hydrochloric acid ethanol solution is 40 wt%, the amount of hydrochloric acid is 2.3 mol), NaNO 2 Aqueous solution (NaNO 2 The concentration of NaNO is 3 mol / L. 2 The amount is 1.1 mol) at 5°C, stirred, and the stirring speed is controlled to 260r / min, and a diazotization reaction occurs. The reaction time is controlled to 1.5h to obtain a reaction solution containing aniline diazonium salt; the reaction formula is as follows:

[0089]

[0090] Step 2): Add 30 g of catalyst (the catalyst is 25 g of CaCl 2 , 5g of zeolite molecular sieve), NH 4 HSO 3 Solution (NH 4 HSO 3The concentration of NH 4 HSO 3 The amount is 2.8 mol), and a reduction reaction occurs at 40°C. The reaction time is controlled to be 4 hours. The reaction solution containing diazobenzenedisulfonic acid amine is obtained by filtration. The reaction formula is shown below:

[0091]

[0092] Step 3): Add hydrochloric acid ethanol solution (the concentration of hydrochloric acid ethanol solution is 30wt%, the amount of hydrochloric acid is 4.8mol) to the reaction solution containing diazobenzenedisulfonic acid amine prepared in step 2), react at 80°C, control the reaction time to 1.5h, cool to 30°C, crystallize, centrifuge, and obtain phenylhydrazine hydrochloride. The reaction formula is as follows:

[0093] ;

[0094] ;

[0095] The yield of phenylhydrazine hydrochloride was calculated based on aniline in step 1), and the yield of phenylhydrazine hydrochloride was 95.9% and the purity was 99.7%.

[0096] Example 4

[0097] Example 4 provides a method for synthesizing phenylhydrazine hydrochloride. The method is the same as that of Example 1. The only difference between Example 4 and Example 1 is that in step 1), NaNO 2 The concentration of the aqueous solution is 1.8 mol / L.

[0098] The yield of phenylhydrazine hydrochloride was calculated based on aniline in step 1), and the yield of phenylhydrazine hydrochloride was 89.1% and the purity was 97.1%.

[0099] Example 5

[0100] Example 5 provides a method for synthesizing phenylhydrazine hydrochloride. The synthesis method is the same as that of Example 1. The only difference between Example 5 and Example 1 is that the concentration of the hydrochloric acid ethanol solution in step 1) is 25wt%.

[0101] The yield of phenylhydrazine hydrochloride was calculated based on aniline in step 1), and the yield of phenylhydrazine hydrochloride was 92.7% and the purity was 98.7%.

[0102] Example 6

[0103] Example 6 provides a method for synthesizing phenylhydrazine hydrochloride. The synthesis method is the same as that of Example 1. The only difference between Example 6 and Example 1 is that the stirring speed in step 1) is controlled to be 160 r / min.

[0104] The yield of phenylhydrazine hydrochloride was calculated based on aniline in step 1), and the yield of phenylhydrazine hydrochloride was 93.2% and the purity was 99.1%.

[0105] Example 7

[0106] Example 7 provides a method for synthesizing phenylhydrazine hydrochloride. The method is the same as that of Example 1. The only difference between Example 7 and Example 1 is that in step 2), 18 g of catalyst (the catalyst is 13.5 g of CaCl 2 , and 4.5 g of zeolite molecular sieve).

[0107] The yield of phenylhydrazine hydrochloride was calculated based on aniline in step 1), and the yield of phenylhydrazine hydrochloride was 88.4% and the purity was 99.2%.

[0108] Example 8

[0109] Example 8 provides a method for synthesizing phenylhydrazine hydrochloride. The method is the same as that of Example 1. The only difference between Example 8 and Example 1 is that in step 2), 25 g of catalyst (the catalyst is 12.5 g of CaCl 2 , 12.5 g of zeolite molecular sieve).

[0110] The yield of phenylhydrazine hydrochloride was calculated based on aniline in step 1), and the yield of phenylhydrazine hydrochloride was 89.1% and the purity was 99.3%.

[0111] Example 9

[0112] Example 9 provides a method for synthesizing phenylhydrazine hydrochloride. The synthesis method is the same as that of Example 1. The only difference between Example 9 and Example 1 is that the concentration of the hydrochloric acid ethanol solution in step 3) is 25wt%.

[0113] The yield of phenylhydrazine hydrochloride was calculated based on aniline in step 1), and the yield of phenylhydrazine hydrochloride was 87.1% and the purity was 98.5%.

[0114] Example 10

[0115] Example 10 provides a method for synthesizing phenylhydrazine hydrochloride. The synthesis method is the same as that of Example 1. The only difference between Example 10 and Example 1 is that the temperature is lowered to 15° C. in step 3).

[0116] The yield of phenylhydrazine hydrochloride was calculated based on aniline in step 1), and the yield of phenylhydrazine hydrochloride was 93.2% and the purity was 98.1%.

[0117] Comparative Example 1

[0118] Comparative Example 1 provides a method for synthesizing phenylhydrazine hydrochloride. The synthesis method is the same as that of Example 1. The only difference between Comparative Example 1 and Example 1 is that in step 1), the ethanol hydrochloric acid solution is replaced by an aqueous hydrochloric acid solution.

[0119] The yield of phenylhydrazine hydrochloride was calculated based on aniline in step 1), and the yield of phenylhydrazine hydrochloride was 80.3% and the purity was 93.5%.

[0120] Comparative Example 2

[0121] Comparative Example 2 provides a method for synthesizing phenylhydrazine hydrochloride. The synthesis method is the same as that of Example 1. The only difference between Comparative Example 2 and Example 1 is that in step 2), no catalyst is added.

[0122] The yield of phenylhydrazine hydrochloride was calculated based on aniline in step 1), and the yield of phenylhydrazine hydrochloride was 78.4% and the purity was 94.3%.

[0123] Comparative Example 3

[0124] Comparative Example 3 provides a method for synthesizing phenylhydrazine hydrochloride. The synthesis method is the same as that of Example 1. The only difference between Comparative Example 3 and Example 1 is that in step 2), the catalyst is 25 g of CaCl 2 Contains no zeolite molecular sieve.

[0125] The yield of phenylhydrazine hydrochloride was calculated based on aniline in step 1), and the yield of phenylhydrazine hydrochloride was 83.1% and the purity was 95.9%.

[0126] Comparative Example 4

[0127] Comparative Example 4 provides a method for synthesizing phenylhydrazine hydrochloride. The synthesis method is the same as that of Example 1. The only difference between Comparative Example 4 and Example 1 is that in step 2), the catalyst is 25 g of zeolite molecular sieve and does not contain CaCl 2 .

[0128] The yield of phenylhydrazine hydrochloride was calculated based on aniline in step 1), and the yield of phenylhydrazine hydrochloride was 84.3% and the purity was 95.6%.

[0129] Comparative Example 5

[0130] Comparative Example 5 provides a method for synthesizing phenylhydrazine hydrochloride. The synthesis method is the same as that of Example 1. The only difference between Comparative Example 5 and Example 1 is that in step 3), the ethanol hydrochloric acid solution is replaced by an aqueous hydrochloric acid solution.

[0131] The yield of phenylhydrazine hydrochloride was calculated based on aniline in step 1), and the yield of phenylhydrazine hydrochloride was 79.2% and the purity was 92.7%.

[0132] By comparing Example 1 with Comparative Example 1, it can be seen that in step 1), the ethanol hydrochloric acid solution is replaced by an aqueous hydrochloric acid solution, and the yield and purity of phenylhydrazine hydrochloride are reduced.

[0133] Comparison between Example 1 and Comparative Example 2 shows that when no catalyst is added in step 2), the yield and purity of phenylhydrazine hydrochloride are reduced.

[0134] Comparison between Example 1 and Comparative Examples 3 and 4 shows that when the catalyst contains only CaCl 2 , does not contain zeolite molecular sieve or the catalyst only contains zeolite molecular sieve and does not contain CaCl 2 When phenylhydrazine hydrochloride is used, the yield and purity of phenylhydrazine hydrochloride are reduced.

[0135] By comparing Example 1 with Comparative Example 5, it can be seen that when the hydrochloric acid ethanol solution is replaced by hydrochloric acid aqueous solution in step 3), the yield of phenylhydrazine hydrochloride is reduced and the purity is reduced.

[0136] The above are all preferred embodiments of the present application, and the protection scope of the present application is not limited thereto. Therefore, any equivalent changes made according to the structure, shape, and principle of the present application should be included in the protection scope of the present application.

Claims

1. A method for synthesizing phenylhydrazine hydrochloride, characterized in that: The steps include: Step 1): Aniline, ethanolic hydrochloric acid solution and NaNO2 solution are stirred at 0-5°C to undergo diazotization reaction to obtain a reaction solution containing aniline diazonium salt; Step 2): Add a catalyst and NH4HSO3 solution to the reaction solution containing aniline diazonium salt obtained in step 1), perform a reduction reaction at 30-40°C, and filter to obtain a reaction solution containing diazonium benzene disulfonic acid amine; the catalyst is a mixture of CaCl2 and zeolite molecular sieve; Step 3): Adding hydrochloric acid ethanol solution to the reaction solution containing diazobenzenedisulfonic acid amine prepared in step 2), reacting at 70-80° C., cooling, crystallizing, and centrifuging to obtain the phenylhydrazine hydrochloride.

2. The synthetic method of phenylhydrazine hydrochloride according to claim 1, characterized in that In the step 1), the concentration of the hydrochloric acid ethanol solution is 25-40wt%.

3. The synthetic method of phenylhydrazine hydrochloride according to claim 1, characterized in that, In the step 1), the concentration of the NaNO2 solution is 1.8-3 mol / L.

4. The synthetic method of phenylhydrazine hydrochloride according to claim 1, characterized in that: In the step 1), the molar ratio of aniline, hydrochloric acid and NaNO2 is 1:(2.3-2.8):(1.1-1.5).

5. The synthetic method of phenylhydrazine hydrochloride according to claim 1, characterized in that, In the step 1), the stirring speed is controlled to be 160-260 r / min.

6. The method for synthesizing phenylhydrazine hydrochloride according to claim 1, characterized in that: In the step 2), the concentration of the NH4HSO3 solution is 50-60wt%, and the molar ratio of NH4HSO3 to aniline in the step 1) is (2.5-2.8):

1.

7. The method for synthesizing phenylhydrazine hydrochloride according to claim 1, characterized in that: In the step 2), the mass molar ratio of the catalyst to the aniline in the step 1) is 18-30 g: 1 mol.

8. The method for synthesizing phenylhydrazine hydrochloride according to claim 1, characterized in that: In the step 2), the mass ratio of CaCl2 to zeolite molecular sieve in the catalyst is (1-5):

1.

9. The method for synthesizing phenylhydrazine hydrochloride according to claim 1, characterized in that: In the step 3), the concentration of the hydrochloric acid ethanol solution is 25-40wt%, and the molar ratio of hydrochloric acid to aniline in the step 1) is (4.5-4.8):

1.

10. The method for synthesizing phenylhydrazine hydrochloride according to claim 1, characterized in that: In the step 3), the temperature is lowered to 15-30°C.

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