A kind of production method of benzylhydroxylamine hydrochloride

Abstract

The present application relates to the field of pharmaceutical technology, and specifically discloses a method for producing benzylhydroxylamine hydrochloride, wherein benzaldehyde and hydroxylamine hydrochloride are used as raw materials to react to obtain benzaldehyde oxime, and the benzaldehyde oxime is then hydrogenated and reduced over a hydrochloric acid-passivated palladium-carbon catalyst to obtain benzylhydroxylamine hydrochloride; the synthetic route is as follows:. The present application adopts the above synthetic route to produce benzylhydroxylamine hydrochloride in accordance with atom economy, and uses a hydrochloric acid-passivated palladium-carbon catalyst to hydrogenate and reduce benzaldehyde oxime, and the reduction reaction is relatively mild, low-cost, and safer and more environmentally friendly. The obtained benzylhydroxylamine hydrochloride has a high yield and purity, and is of good practicality.

Description

Technical Field

[0001] The present application relates to the field of pharmaceutical technology, and more specifically, to a method for producing benzylhydroxylamine hydrochloride. Background Art

[0002] N-Benzylhydroxylamine hydrochloride is an important organic synthesis intermediate. The nitrone prepared by its reaction with aldehydes or ketones can be further subjected to 1,3-cycloaddition to construct isoxazoline. It is widely used in the synthesis of multiple pharmaceutical intermediates and has huge market demand.

[0003] The existing synthesis method of this compound mainly uses dibenzylamine as the starting material, oxidizes it with hydrogen peroxide to obtain C-phenyl-N-benzyl nitrone, and then reacts with hydroxylamine hydrochloride to obtain the product. The first step of this method uses methanol as a solvent, and a large amount of excess hydrogen peroxide is added for oxidation, which poses a great safety risk. The two-step yield is about 60%, the reaction yield is biased, and benzaldehyde is produced as a by-product, which is difficult to handle. The synthesis route is as follows:

[0004] .

[0005] Therefore, it is necessary to design a production method of benzylhydroxylamine hydrochloride that is safe, environmentally friendly, low in cost, and has high yield and purity. Summary of the invention

[0006] In order to design a safe, environmentally friendly, low-cost, high-yield and high-purity production method for benzylhydroxylamine hydrochloride, the present application provides a production method for benzylhydroxylamine hydrochloride, using the following technical solution:

[0007] A method for producing benzylhydroxylamine hydrochloride comprises the following steps: using benzaldehyde and hydroxylamine hydrochloride as raw materials to react to obtain benzaldehyde oxime, and then subjecting the benzaldehyde oxime to hydrogenation reduction with a hydrochloric acid-passivated palladium-carbon catalyst to obtain benzylhydroxylamine hydrochloride; the synthetic route is as follows:

[0008] .

[0009] The production method is used to produce benzylhydroxylamine hydrochloride, the reduction reaction is relatively mild, the cost is low, and it is safer and more environmentally friendly; the yield and purity of the obtained benzylhydroxylamine hydrochloride are both high, and the industrialization prospect is good.

[0010] The analysis is as follows: first, using benzaldehyde and hydroxylamine hydrochloride as raw materials is in line with atom economy, which can maximize the use of raw materials and reduce the generation of by-products; and in the process of reducing benzaldehyde oxime, a palladium-carbon catalyst is used to catalyze the reaction, and the catalyst price is relatively low, which comprehensively achieves the purpose of cost saving. At the same time, the palladium-carbon catalyst is further passivated with hydrochloric acid, making the hydrogenation reduction process milder, which can effectively reduce the generation of side reactions and is safer.

[0011] In a specific embodiment, in the benzaldehyde oxime hydrogenation reduction step, the pH of the hydrogenation reaction solution is adjusted to 2-5 before the reaction is carried out.

[0012] In a specific embodiment, in the benzaldehyde oxime hydrogenation reduction step, the pH of the hydrogenation reaction solution is adjusted to 3-4 before the reaction is carried out.

[0013] By adopting the above technical scheme, the pH of the hydrogenation reaction liquid is adjusted to 2-5 before the hydrogenation reduction reaction, and the pH is further preferably adjusted to 3-4. While creating a suitable hydrochloric acid system, the passivation degree of the palladium-carbon catalyst can be controlled within a suitable range, and the actual production effect is better.

[0014] In a specific embodiment, the content of palladium metal in the palladium carbon catalyst is 0.5-5%.

[0015] In a specific embodiment, the content of palladium metal in the palladium carbon catalyst is 1%.

[0016] In a specific embodiment, after the hydrogenation reduction reaction is completed, the palladium-carbon catalyst is recovered, and the recovered palladium-carbon catalyst is regenerated to obtain a regenerated palladium-carbon catalyst; specifically comprising the following steps:

[0017] The recovered palladium-carbon catalyst is repeatedly washed with hot water at 80-100°C to obtain a pretreated palladium-carbon catalyst; the pretreated palladium-carbon catalyst is then added to a mercurous nitrate solution, filtered after ultrasonic impregnation, the filter residue is washed with water and then added to carbon tetrachloride, and ultrasonic impregnation is continued. After the impregnation is completed, the upper liquid is taken for filtration, and the filter residue is repeatedly washed with an ethanol solution until carbon tetrachloride is no longer detected in the washing liquid, and then washed with water to obtain a regenerated palladium-carbon catalyst.

[0018] The recycling of palladium-carbon catalysts is one of the important ways to effectively save production costs. However, due to the passivation effect of the hydrochloric acid system, the recycled palladium-carbon catalyst contains more chloride ions, which makes the recycled palladium-carbon catalyst easy to deactivate. If it is not treated, the catalytic activity of the recycled palladium-carbon catalyst is difficult to meet the requirements when it is reused, and the degree of hydrochloric acid passivation is difficult to control during the production of benzylhydroxylamine hydrochloride. The traditional way to remove chloride ions from palladium-carbon catalysts is through simple water washing, but the removal effect is limited.

[0019] Therefore, the recovered palladium-carbon catalyst is first repeatedly washed with hot water to preliminarily remove chloride ions and some organic matter in the palladium-carbon catalyst by dissolving. Then it is further treated with mercurous nitrate solution so that the residual chloride ions are combined with mercurous ions and precipitated in the form of mercurous chloride. Carbon tetrachloride is subsequently used for impregnation. Since the density of carbon tetrachloride is greater than that of palladium-carbon, and the density of carbon tetrachloride is less than that of mercurous chloride, palladium-carbon tends to float in carbon tetrachloride, while mercurous chloride will precipitate to the bottom of carbon tetrachloride, thereby achieving the separation of palladium-carbon and mercurous chloride, that is, the filter residue after the upper liquid is filtered is palladium-carbon, and then after washing with ethanol and water in turn, a relatively pure regenerated palladium-carbon catalyst can be obtained, and the effect of subsequent catalytic reduction is better.

[0020] In a specific embodiment, the concentration of the mercurous nitrate solution is 0.1-0.5 mol / L.

[0021] In a specific embodiment, in the benzaldehyde oxime hydrogenation reduction step, the hydrogenation pressure is 0.1-0.5 MPa.

[0022] In a specific embodiment, in the benzaldehyde oxime hydrogenation reduction step, the hydrogenation pressure is 0.1-0.2 MPa.

[0023] In a specific embodiment, in the benzaldehyde oxime hydrogenation reduction step, the molar ratio of the hydrogen absorption amount to the benzaldehyde oxime is (1-1.1):1.

[0024] In summary, this application has the following beneficial effects:

[0025] 1. In the production process provided in this application, the raw materials are relatively cheap and conform to atom economy, the synthesis route is short, and the yield and purity of the obtained benzylhydroxylamine hydrochloride are high, which meets the needs of industrial production.

[0026] 2. In the present application, a hydrochloric acid-passivated palladium-carbon catalyst is used to catalyze hydrogenation reduction to obtain the product, which makes the reduction reaction milder, can effectively reduce the occurrence of side reactions, and is safer and more environmentally friendly.

[0027] 3. In the present application, the palladium-carbon catalyst is recovered and processed, and the chloride ions in the recovered palladium-carbon catalyst are effectively removed, thereby obtaining a relatively pure regenerated palladium-carbon catalyst, which has a better effect when put into use again, further saving costs. DETAILED DESCRIPTION

[0028] The present application is further described in detail below in conjunction with examples and comparative examples. The raw materials involved in the present application can all be obtained commercially.

[0029] The solvents in the following examples and comparative examples include, but are not limited to, deionized water, methanol, ethanol, isopropanol, propylene glycol, and preferably methanol.

[0030] Example 1

[0031] A method for producing benzylhydroxylamine hydrochloride comprises the following steps: using benzaldehyde and hydroxylamine hydrochloride as raw materials to react to obtain benzaldehyde oxime, and then subjecting the benzaldehyde oxime to hydrogenation reduction with a hydrochloric acid-passivated palladium-carbon catalyst to obtain benzylhydroxylamine hydrochloride; the synthetic route is as follows:

[0032] ;

[0033] The specific production steps are as follows:

[0034] 1. Preparation of benzaldehyde oxime:

[0035] 106.1 kg of benzaldehyde and 120 kg of soda ash were added to 1000 L of methanol. After the addition was completed, the mixture was cooled to 8°C. The temperature was controlled to add 73.5 kg of hydroxylamine hydrochloride in batches. After the addition was completed, the mixture was reacted at room temperature for 4 hours. The temperature was controlled to be 30°C and the methanol was recovered under negative pressure until no liquid was discharged. 1000 L of water was added, the mixture was stirred and cooled to 2°C, the mixture was discharged and centrifuged, a small amount of petroleum ether was used for rinsing, and the mixture was dried under vacuum at 25°C to obtain benzaldehyde oxime with a yield of 95.9%.

[0036] 2. Preparation of benzylhydroxylamine hydrochloride:

[0037] 100 kg of benzaldehyde oxime, 600 L of methanol, and 3.5 kg of 1% palladium on carbon were added to a hydrogenation kettle to obtain a hydrogenation reaction liquid; 7 kg of CP hydrochloric acid was added dropwise to adjust the pH of the hydrogenation reaction liquid to 3, and the mixture was stirred at room temperature for 2 hours, and then hydrogen was introduced to a hydrogenation pressure of 0.2 MPa, and the hydrogen absorption was controlled to be 18.2 to 18.5 m 3 , that is, the molar ratio of hydrogen absorption to benzaldehyde oxime is (1-1.1): 1, stop stirring, replace with nitrogen and filter to recover palladium carbon, strictly protect the mother liquor with nitrogen, control the temperature at 5°C and add 301.3 kg of 10% hydrochloric acid methanol dropwise, pH to 1.6, concentrate most of the methanol at 30°C in a water bath under negative pressure, add 600 L of tert-butyl methyl ether, beat for 1 hour, and centrifuge to obtain benzylhydroxylamine hydrochloride product with a purity of 98.9%, a melting point of 108.3-110.2°C, and a yield of 86.0%.

[0038] Example 2

[0039] The specific production steps of this embodiment are as follows:

[0040] 1. Preparation of benzaldehyde oxime:

[0041] 106.1 kg of benzaldehyde and 120 kg of soda ash were added to 1000 L of methanol. After the addition was completed, the mixture was cooled to 5°C. The temperature was controlled and 73.5 kg of hydroxylamine hydrochloride was added in batches. After the addition was completed, the mixture was reacted at room temperature for 5 hours. The temperature was controlled to be 25°C and the methanol was recovered under negative pressure until no liquid was discharged. 1000 L of water was added and the mixture was stirred and cooled to 5°C. The mixture was discharged and centrifuged, rinsed with a small amount of petroleum ether, and dried under vacuum at 25°C to obtain benzaldehyde oxime with a yield of 95.1%.

[0042] 2. Preparation of benzylhydroxylamine hydrochloride:

[0043] 100 kg of benzaldehyde oxime, 600 L of methanol, and 3.5 kg of 0.5% palladium on carbon were added to a hydrogenation kettle to obtain a hydrogenation reaction liquid; 10 kg of CP hydrochloric acid was added dropwise to adjust the pH of the hydrogenation reaction liquid to 2, and the mixture was stirred at room temperature for 2 hours, and then hydrogen was introduced to a hydrogenation pressure of 0.1 MPa, and the hydrogen absorption was controlled to be 18.2 to 18.5 m 3 , that is, the molar ratio of hydrogen absorption to benzaldehyde oxime is (1-1.1): 1, stop stirring, replace with nitrogen and filter to recover palladium carbon, strictly protect the mother liquor with nitrogen, control the temperature at 8°C and add 301.3 kg of 10% hydrochloric acid methanol dropwise, pH to 1.3, concentrate most of the methanol at 25°C in a water bath with negative pressure, add 600 L of tert-butyl methyl ether, beat for 1 hour, and centrifuge to obtain benzylhydroxylamine hydrochloride product with a purity of 99.3%, a melting point of 108.3-110.2°C, and a yield of 85.4%.

[0044] Example 3

[0045] The specific production steps of this embodiment are as follows:

[0046] 1. Preparation of benzaldehyde oxime:

[0047] 106.1 kg of benzaldehyde and 120 kg of soda ash were added to 1000 L of methanol. After the addition was completed, the mixture was cooled to 10°C. The temperature was controlled to add 73.5 kg of hydroxylamine hydrochloride in batches. After the addition was completed, the mixture was reacted at room temperature for 3 hours. The temperature was controlled to be 35°C and the methanol was recovered under negative pressure until no liquid was discharged. 1000 L of water was added and the mixture was stirred and cooled to 0°C. The mixture was discharged and centrifuged, rinsed with a small amount of petroleum ether, and dried under vacuum at 25°C to obtain benzaldehyde oxime with a yield of 94.5%.

[0048] 2. Preparation of benzylhydroxylamine hydrochloride:

[0049] 100 kg of benzaldehyde oxime, 600 L of methanol, and 3.5 kg of 5% palladium on carbon were added to a hydrogenation kettle to obtain a hydrogenation reaction liquid; 3 kg of CP hydrochloric acid was added dropwise to adjust the pH of the hydrogenation reaction liquid to 5, and the mixture was stirred at room temperature for 2 hours, and then hydrogen was introduced to a hydrogenation pressure of 0.5 MPa, and the hydrogen absorption was controlled to be 18.2 to 18.5 m 3, that is, the molar ratio of hydrogen absorption to benzaldehyde oxime is (1-1.1): 1, stop stirring, replace with nitrogen and filter to recover palladium carbon, strictly protect the mother liquor with nitrogen, control the temperature at 5°C and add 301.3 kg of 10% hydrochloric acid methanol dropwise, pH to 1.9, concentrate most of the methanol at 35°C in a water bath with negative pressure, add 600 L of tert-butyl methyl ether, beat for 1 hour, and centrifuge to obtain benzylhydroxylamine hydrochloride product with a purity of 98.2%, a melting point of 108.3-110.2°C, and a yield of 86.6%.

[0050] Example 4

[0051] The difference between this embodiment and embodiment 1 is that in the preparation step of benzylhydroxylamine hydrochloride, 10 kg of CP hydrochloric acid is added dropwise to adjust the pH of the hydrogenation reaction liquid to 2;

[0052] The purity of benzylhydroxylamine hydrochloride product is 97.7%, and the yield is 84.0%.

[0053] Example 5

[0054] The difference between this embodiment and embodiment 1 is that in the preparation step of benzylhydroxylamine hydrochloride, 5.6 kg of CP hydrochloric acid is added dropwise to adjust the pH of the hydrogenation reaction liquid to 4;

[0055] The purity of benzylhydroxylamine hydrochloride product is 99.1%, and the yield is 86.2%.

[0056] Example 6

[0057] The difference between this embodiment and embodiment 1 is that in the preparation step of benzylhydroxylamine hydrochloride, 3 kg of CP hydrochloric acid is added dropwise to adjust the pH of the hydrogenation reaction liquid to 5;

[0058] The purity of benzylhydroxylamine hydrochloride product is 97.4%, and the yield is 84.5%.

[0059] Example 7

[0060] The difference between this embodiment and embodiment 1 is that in the preparation step of benzylhydroxylamine hydrochloride, the content of palladium metal in the palladium carbon catalyst is 0.5%;

[0061] The purity of benzylhydroxylamine hydrochloride product is 98.0%, and the yield is 84.8%.

[0062] Example 8

[0063] The difference between this embodiment and embodiment 1 is that in the preparation step of benzylhydroxylamine hydrochloride, the content of palladium metal in the palladium carbon catalyst is 5%;

[0064] The purity of benzylhydroxylamine hydrochloride product is 96.2%, and the yield is 85.3%.

[0065] Example 9

[0066] The difference between this embodiment and embodiment 1 is that in the preparation step of benzylhydroxylamine hydrochloride, hydrogen is passed to a hydrogenation pressure of 0.1 MPa;

[0067] The purity of benzylhydroxylamine hydrochloride product is 98.5%, and the yield is 86.4%.

[0068] Example 10

[0069] The difference between this embodiment and embodiment 1 is that in the preparation step of benzylhydroxylamine hydrochloride, hydrogen is passed to a hydrogenation pressure of 0.5 MPa;

[0070] The purity of benzylhydroxylamine hydrochloride product is 97.7%, and the yield is 84.3%.

[0071] Embodiment 11

[0072] The difference between this embodiment and embodiment 1 is that in the preparation step of benzylhydroxylamine hydrochloride, the palladium carbon recovered by pressure filtration is regenerated to obtain a regenerated palladium carbon catalyst; specifically, the following steps are included:

[0073] The recovered palladium-carbon catalyst is repeatedly washed twice with hot water at 95°C, each time for 5 minutes, to obtain a pretreated palladium-carbon catalyst; then the pretreated palladium-carbon catalyst is added to a 0.3 mol / L mercurous nitrate solution, ultrasonically immersed for 2 hours and then filtered, the filter residue is washed with water and then added to carbon tetrachloride, and ultrasonic immersion is continued for 15 minutes. After the immersion is completed, the upper liquid (referring to the liquid layer above the bottom sediment) is taken and filtered again, and the filter residue is repeatedly washed with an ethanol solution until carbon tetrachloride is no longer detected in the washing liquid, and then repeatedly washed with water three times to obtain a regenerated palladium-carbon catalyst;

[0074] The regenerated palladium-carbon catalyst was used to replace the palladium-carbon catalyst in Example 1 in equal amounts to obtain benzylhydroxylamine hydrochloride with a purity of 96.2% and a yield of 83.5%.

[0075] Example 12

[0076] The difference between this embodiment and embodiment 11 is that the concentration of mercurous nitrate solution is 0.1 mol / L;

[0077] The regenerated palladium-carbon catalyst was used to replace the palladium-carbon catalyst in Example 1 in equal amounts to obtain benzylhydroxylamine hydrochloride with a purity of 95.6% and a yield of 83.8%.

[0078] Example 13

[0079] The difference between this embodiment and embodiment 11 is that the concentration of mercurous nitrate solution is 0.5 mol / L;

[0080] The regenerated palladium-carbon catalyst was used to replace the palladium-carbon catalyst in Example 1 in equal amounts to obtain benzylhydroxylamine hydrochloride with a purity of 94.9% and a yield of 84.1%.

[0081] Embodiment 14

[0082] The difference between this embodiment and embodiment 11 is that the concentration of the mercurous nitrate solution is 1 mol / L;

[0083] The regenerated palladium-carbon catalyst was used to replace the palladium-carbon catalyst in Example 1 in equal amounts to obtain benzylhydroxylamine hydrochloride with a purity of 92.4% and a yield of 81.7%.

[0084] Comparative Example 1

[0085] The difference between this comparative example and Example 1 is that the palladium carbon catalyst is replaced by an equal amount of sodium cyanoborohydride, and the introduction of hydrogen is omitted;

[0086] The purity of benzylhydroxylamine hydrochloride product is 87.8%, and the yield is 81.3%.

[0087] Comparative Example 2

[0088] The difference between this comparative example and Example 1 is that the palladium carbon catalyst is not passivated with hydrochloric acid, that is, in the preparation step of benzylhydroxylamine hydrochloride, CP hydrochloric acid is not added dropwise to adjust the pH of the hydrogenation reaction solution;

[0089] The purity of benzylhydroxylamine hydrochloride product is 89.2%, and the yield is 82.5%.

[0090] Data analysis

[0091] The yield of benzylhydroxylamine hydrochloride produced in Examples 1-10 can reach more than 84%, and the purity can reach more than 96%, which means that the purity and yield of benzylhydroxylamine hydrochloride produced by the production method provided in the present application can reach a high level, which meets the needs of industrial production.

[0092] In Comparative Example 1, sodium cyanoborohydride was used as the reduction catalyst, which was not only more expensive than the palladium carbon catalyst, but also the purity and yield of the obtained benzylhydroxylamine hydrochloride were significantly lower than those in Example 1. This may be because side reactions and by-products occurred during the reduction reaction catalyzed by the sodium cyanoborohydride catalyst. In addition, the catalytic reaction of sodium cyanoborohydride was relatively strong, and the production safety was relatively poor.

[0093] In Comparative Example 2, the palladium-carbon catalyst was not passivated with hydrochloric acid, and the purity and yield of the obtained benzylhydroxylamine hydrochloride were significantly lower than those in Example 1, which further illustrates that ensuring the catalytic reduction reaction is relatively mild is of positive significance for improving the purity and yield of the product.

[0094] In addition, the palladium-carbon catalyst recovered in Example 1 was repeatedly washed three times with deionized water to obtain a regenerated palladium-carbon catalyst, which was reused in production, and the benzylhydroxylamine hydrochloride purity obtained using the production process in Example 1 was 81.9%, and the yield was 70.8%. The regenerated palladium-carbon catalyst obtained in Examples 11-14 was reused for production, and the obtained benzylhydroxylamine hydrochloride purity and yield were significantly higher. This is because the effect of only relying on water washing to remove chloride ions is poor, which makes it difficult to judge the appropriate degree of passivation when using hydrochloric acid to passivate the palladium-carbon catalyst, thereby causing the product purity and yield to become low. It also fully illustrates that the regeneration treatment of the palladium-carbon catalyst after recovery in Examples 11-14 has positive significance, and the practical effect is better.

[0095] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make modifications to the present embodiment without any creative contribution as needed, but such modifications are protected by the patent law as long as they are within the scope of the claims of the present application.

Claims

1. A method for producing benzylhydroxylamine hydrochloride, characterized in that: Benzaldehyde and hydroxylamine hydrochloride are used as raw materials to react to obtain benzaldehyde oxime, which is then hydrogenated and reduced over a hydrochloric acid-passivated palladium-carbon catalyst to obtain benzylhydroxylamine hydrochloride. The synthetic route is as follows: 。 2. The method for producing benzylhydroxylamine hydrochloride according to claim 1, characterized in that: In the benzaldehyde oxime hydrogenation reduction step, the pH of the hydrogenation reaction solution is adjusted to 2-5 before the reaction is carried out.

3. The method for producing benzylhydroxylamine hydrochloride according to claim 2, characterized in that: In the benzaldehyde oxime hydrogenation reduction step, the pH of the hydrogenation reaction solution is adjusted to 3-4 before the reaction is carried out.

4. The method for producing benzylhydroxylamine hydrochloride according to claim 1, characterized in that: The content of palladium metal in the palladium carbon catalyst is 0.5-5%.

5. The method for producing benzylhydroxylamine hydrochloride according to claim 4, characterized in that: The content of palladium metal in the palladium carbon catalyst is 1%.

6. The method for producing benzylhydroxylamine hydrochloride according to claim 1, characterized in that: After the hydrogenation reduction reaction is completed, the palladium-carbon catalyst is recovered, and the recovered palladium-carbon catalyst is regenerated to obtain a regenerated palladium-carbon catalyst; specifically comprising the following steps: The recovered palladium-carbon catalyst is repeatedly washed with hot water at 80-100°C to obtain a pretreated palladium-carbon catalyst; the pretreated palladium-carbon catalyst is then added to a mercurous nitrate solution, filtered after ultrasonic impregnation, the filter residue is washed with water and then added to carbon tetrachloride, and ultrasonic impregnation is continued. After the impregnation is completed, the upper liquid is taken for filtration, and the filter residue is repeatedly washed with an ethanol solution until carbon tetrachloride is no longer detected in the washing liquid, and then washed with water to obtain a regenerated palladium-carbon catalyst.

7. The method for producing benzylhydroxylamine hydrochloride according to claim 6, characterized in that: The concentration of mercurous nitrate solution is 0.1-0.5 mol / L.

8. The method for producing benzylhydroxylamine hydrochloride according to claim 1, characterized in that: In the benzaldehyde oxime hydrogenation reduction step, the hydrogenation pressure is 0.1-0.5 MPa.

9. The method for producing benzylhydroxylamine hydrochloride according to claim 8, characterized in that: In the benzaldehyde oxime hydrogenation reduction step, the hydrogenation pressure is 0.1-0.2 MPa.

10. The method for producing benzylhydroxylamine hydrochloride according to claim 1, characterized in that: In the benzaldehyde oxime hydrogenation reduction step, the molar ratio of the hydrogen absorption amount to the benzaldehyde oxime is (1-1.1):1.

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