Method for preparing hydroxylamine hydrochloride through ketoxime method hydrolysis

Abstract

The invention relates to a method for preparing hydroxylamine hydrochloride through ketoxime hydrolysis, and belongs to the technical field of hydroxylamine hydrochloride. The method comprises the following steps: pretreating ketoxime and a hydrochloric acid solution through a pressurized nanobubble fluidized bed, heating, then carrying out reaction distillation, and continuously steaming out a byproduct ketone during the period; after the reaction is finished, freezing and separating out the mixed solution, and filtering through cross-flow filtering equipment to obtain hydroxylamine hydrochloride crystals; performing negative pressure distillation concentration and cold separation on the filtrate, and repeating for 3 times to obtain hydroxylamine hydrochloride crystals and crystallization mother liquor; the crystallization mother liquor is returned to the reaction kettle to continuously participate in the hydrolysis reaction; the filtering membrane for the cross-flow filtering equipment is subjected to plasma modification treatment. The hydroxylamine hydrochloride prepared by the method disclosed by the invention has relatively high purity and yield and low chromaticity.

Description

Technical Field

[0001] The invention relates to the technical field of hydroxylamine hydrochloride, in particular to a method for preparing hydroxylamine hydrochloride by hydrolysis using a ketoxime method. Background Art

[0002] Hydroxylamine hydrochloride is an inorganic substance, a colorless crystalline, hygroscopic, white chemical substance, mainly used as a reducing agent and developer. It is used to prepare oximes in organic synthesis and is also used as a raw material for synthesizing anticancer drugs (hydroxyurea), sulfonamides (sulfamethoxazole) and pesticides (methomildamine).

[0003] Chinese patent CN105540559A: relates to a method for improving the quality and yield of hydroxylamine hydrochloride, which comprises the following steps: (a) adding hydroxylamine hydrochloride hydrolyzate to a concentration kettle, and then adding mother liquor water containing hydroxylamine hydrochloride to the concentration kettle; (b) heating the concentration kettle to a temperature of 60-90°C and a pressure of 500-1000 Pa until crystals are generated in the liquid in the concentration kettle; (c) naturally cooling the concentration kettle to 10-30°C, then opening and draining the filtrate, adding ethanol to wash the filter residue, and removing and drying.

[0004] Chinese patent CN107311128A: provides a method for preparing hydroxylamine hydrochloride, specifically a method for preparing hydroxylamine hydrochloride using hydrogen peroxide and ammonium chloride, comprising the following steps: first, catalyzing hydrogen peroxide, ammonia, and acetone or butanone to synthesize ketoxime; then, reacting the ketoxime with ammonium chloride under negative pressure to produce hydroxylamine hydrochloride, ammonia, acetone or butanone; and recovering the acetone or butanone and ammonia for recycling.

[0005] Chinese patent CN112723328A discloses a method for preparing high-purity solid hydroxylamine hydrochloride, comprising the following steps: Step 1, synthesis of hydroxylamine hydrochloride: adding butanone oxime and concentrated hydrochloric acid with a concentration of 36-38% to a reactor according to mass fractions, stirring at 100-300 r / min to mix evenly, heating to 70-90°C, reacting for 50-90 minutes to obtain a solution of butanone, water and hydroxylamine hydrochloride, then evacuating to -0.07 to -0.09 MPa, separating and recovering the butanone to obtain a hydroxylamine hydrochloride aqueous solution; Step 2, purification of hydroxylamine hydrochloride: passing the obtained hydroxylamine hydrochloride aqueous solution through an ion exchange resin adsorption tower to remove impurities such as heavy metal ions and ammonium ions, then cooling the hydroxylamine hydrochloride aqueous solution to 0-2°C to precipitate a large amount of hydroxylamine hydrochloride crystals, filtering under reduced pressure to separate the crystals and water, recovering the water for preparing concentrated hydrochloric acid, and freeze-drying the crystals to fully remove water to obtain a solid hydroxylamine hydrochloride.

[0006] During the reaction, iron ions, particularly ferric ions, may be introduced into the equipment materials or raw materials. In the hydroxylamine hydrochloride system, these ions undergo a redox reaction with hydroxylamine hydrochloride, producing some colored intermediates or oxidation products, which can cause the product color to change.

[0007] Other metal ions: such as calcium, magnesium, and aluminum, which may originate from raw materials or contact materials during the production process. They can catalyze the decomposition of hydroxylamine hydrochloride or react with other impurities in the system to generate colored organic or inorganic compounds, thereby affecting the color of the product. Summary of the Invention

[0008] In order to solve the above problems, the present invention provides a method for preparing hydroxylamine hydrochloride by hydrolysis of ketoxime, the operating steps of which are as follows:

[0009] S1: Pre-treating 30-40 parts of ketoxime and 26-38 parts of hydrochloric acid solution by weight in a pressurized nanobubble fluidized bed, heating, and then performing reactive distillation, during which the by-product ketone is continuously distilled off;

[0010] S2: After the reaction is completed, the mixed solution is frozen to precipitate, and then filtered through a cross-flow filtration device to obtain hydroxylamine hydrochloride crystals;

[0011] S3: The filtrate is concentrated by vacuum distillation and cold precipitation, and repeated three times to obtain hydroxylamine hydrochloride crystals and crystallization mother liquor;

[0012] S4: The crystallization mother liquor is returned to the reactor to continue the hydrolysis reaction;

[0013] The filter membrane used in the cross-flow filtration equipment is prepared by pre-treating with bisindolemaleimide and 2-amino-1,3,5-triazine and then undergoing plasma treatment.

[0014] Furthermore, the ketoxime is one of acetone oxime, butanone oxime and cyclohexanone oxime.

[0015] Furthermore, the mass concentration of the hydrochloric acid solution is 30-35%.

[0016] Furthermore, the reaction temperature of S1 is 60-70° C., and the reaction time is 60-90 min.

[0017] Furthermore, the pressurized nanobubble fluidized bed needs to continuously introduce nitrogen to generate nanobubbles to promote mass transfer; the nitrogen flow rate is 1-3 L / min; the bubble size is 100-300 nm; and the mixing time is 10-30 min.

[0018] Furthermore, the pore size of the filter membrane used in the cross-flow filtration equipment is 0.1-0.5 μm; the operating pressure is 0.3-0.6 MPa; the temperature is 20-30° C.; the flow rate is 30-50 L / min; and the filtration time is 20-50 min.

[0019] Furthermore, the specific operation of the plasma modification treatment of the filter membrane used in the cross-flow filtration equipment is as follows:

[0020] T1: First, pretreat the filter membrane by immersing it in an ethanol solution, adding 1-5% by weight of bisindolemaleimide and 2-6% by weight of 2-amino-1,3,5-triazine in ethanol, and soaking at 60-70°C for 3-6 hours, then taking it out and drying it;

[0021] T2: The filter membrane pretreated in step T1 is then placed in the reaction chamber of the plasma treatment equipment. After the reaction chamber is sealed, the pressure in the reaction chamber is pumped down to 10-20 Pa, and a mixture of ammonia and argon is introduced into the reaction chamber.

[0022] T3: After the treatment is completed, turn off the plasma generator, stop introducing ammonia and argon, slowly introduce air into the reaction chamber to restore the pressure to normal pressure, then remove the filter membrane, rinse it with deionized water 2-3 times, dry it until it is free of moisture, and then add it to the cross-flow filtration equipment for use.

[0023] Furthermore, the volume ratio of ammonia to argon is 1:2-1:3.

[0024] Furthermore, the flow rate of the mixed gas is controlled at 50-80 sccm, so that the pressure in the reaction chamber is maintained at 50-100 Pa.

[0025] Furthermore, the plasma generator is set to have a power of 100-150W and a processing time of 5-10 minutes.

[0026] Reaction mechanism

[0027] 1. Mechanism of amino-olefin addition and membrane activation reaction:

[0028] During membrane pretreatment, the amino group of 2-amino-1,3,5-triazine, leveraging its nucleophilicity, uses the lone pair of electrons from the nitrogen atom to attack the carbon atom of the olefin double bond in the bisindolemaleimide, breaking the π bond of the double bond and forming a new carbon-nitrogen single bond and a carbon cation intermediate. Subsequently, protons in the system combine with the carbon cation to complete the amino-olefin addition reaction, forming a compound containing bisindole and triazine structures on the membrane surface. Entering the plasma treatment stage, high-energy particles from the plasma formed by a mixture of ammonia and argon strike the membrane, allowing the compounds containing bisindole and triazine structures to bind more tightly to the membrane and simultaneously activating the membrane surface groups, such as converting some amino groups into imino groups, providing more active sites for the adsorption of metal ions.

[0029] 2. Adsorption mechanism of iron ions by filter membrane:

[0030] The lone pair electrons of the nitrogen atoms of the amino groups on the surface of the filter membrane can fill the empty d orbitals of the iron ions, forming a monodentate coordination bond to achieve initial adsorption. Moreover, one iron ion can form a multidentate coordination structure with multiple amino groups, such as a stable hexacoordinate structure, which greatly enhances the adsorption capacity of iron ions and prevents their detachment. In addition, in the acidic hydroxylamine hydrochloride system, the amino groups on the surface of the filter membrane are protonated and positively charged, and the anions around the iron ions form an ionic atmosphere. The two are attracted to each other through electrostatic attraction, and the synergistic coordination adsorption promotes the migration of iron ions to the filter membrane, improving removal efficiency.

[0031] 3. Adsorption mechanism of calcium, magnesium and aluminum ions by filter membrane:

[0032] For aluminum ions, the lone pair of electrons from the amino nitrogen atoms on the membrane surface fills its empty orbital, forming a monodentate coordination bond for adsorption. Magnesium ions can form a stable chelate ring structure with two adjacent amino groups on the membrane surface, resulting in strong adsorption through chelation. Calcium ions are attracted to negatively charged groups on the membrane surface (such as a small number of carboxyl anions) through electrostatic attraction, while also coordinating with the amino groups. This combined action of electrostatics and coordination achieves effective adsorption.

[0033] Technical Effects

[0034] The present invention provides a method for preparing hydroxylamine hydrochloride by hydrolysis of ketoxime. Compared with the prior art, the present invention has the following significant effects:

[0035] 1. The inhibitory effect of metal ion adsorption on the reaction:

[0036] The use of a filter membrane containing bisindole and triazine, derived through an amino-olefin addition reaction, effectively reduces the concentration of metal ions such as calcium, magnesium, and aluminum in the solution. These metal ions would catalyze the decomposition of hydroxylamine hydrochloride in the system and may also react with other impurities to form colored compounds. The adsorption of metal ions by the active groups on the filter membrane surface significantly reduces the likelihood of such reactions. This reaction inhibition fundamentally avoids the adverse effects of metal ion participation in the reaction, providing a fundamental guarantee for product quality.

[0037] 2. Guarantee effect on product color:

[0038] The filter membrane's efficient adsorption of metal ions significantly reduces the metal ion content in the solution, effectively avoiding the problem of darkening the product color caused by a series of reactions triggered by metal ions. Product color is a key indicator of its quality. A normal-colored hydroxylamine hydrochloride product not only meets the required appearance but also reflects the stability and purity of its internal components. Therefore, this filter membrane containing bisindole and triazine plays a key role in ensuring product color, enhancing its overall quality and market competitiveness.

[0039] 3. The process of the present invention is simple, the cost of raw materials is low, the purity and yield of hydroxylamine hydrochloride are high, and the quality is stable. DETAILED DESCRIPTION

[0040] In order to further illustrate the technical means and effects adopted by the present invention to achieve the predetermined invention object, the following is a detailed description in conjunction with examples and comparative examples:

[0041] 1. Hydroxylamine hydrochloride yield test: Calculate the amount of substance and the molar yield by weighing the product and the mass of the raw materials used.

[0042] 2. Hydroxylamine hydrochloride purity test: Weigh approximately 1g of sample to the nearest 0.00012g, dissolve in oxygen-free water, transfer to a 250mL volumetric flask, dilute to the mark, and shake well. Use a pipette to transfer 25mL of the solution to a 250mL conical flask. Add 10mL of sulfuric acid solution and 20mL of ammonium ferric sulfate solution and shake well. Slowly heat to boiling and boil for 5 minutes. Add 100mL of oxygen-free water and 2mL of phosphoric acid. Titrate at approximately 60°C with potassium permanganate standard titrant until the solution turns pink. Perform a blank test simultaneously to calculate the product purity.

[0043] 3. Chroma test: measured by visual colorimetry.

[0044] Example 1

[0045] A method for preparing hydroxylamine hydrochloride by ketoxime hydrolysis, the operating steps are:

[0046] S1: 30g of ketoxime and 26g of hydrochloric acid solution were pretreated in a pressurized nanobubble fluidized bed, heated, and then subjected to reactive distillation, during which the by-product acetone was continuously distilled off;

[0047] S2: After the reaction is completed, the mixed solution is frozen to precipitate, and then filtered through a cross-flow filtration device to obtain hydroxylamine hydrochloride crystals;

[0048] S3: The filtrate is concentrated by vacuum distillation and cold precipitation, and repeated three times to obtain hydroxylamine hydrochloride crystals and crystallization mother liquor;

[0049] S4: The crystallization mother liquor is returned to the reactor to continue the hydrolysis reaction;

[0050] The filter membrane used in the cross-flow filtration equipment is prepared by pre-treating with bisindolemaleimide and 2-amino-1,3,5-triazine and then undergoing plasma treatment.

[0051] The ketoxime is acetone oxime.

[0052] The mass concentration of the hydrochloric acid solution is 30%.

[0053] The reaction temperature of S1 is 60° C. and the reaction time is 60 min.

[0054] The pressurized nanobubble fluidized bed needs to be continuously fed with nitrogen to generate nanobubbles to promote mass transfer; the nitrogen flow rate is 1 L / min; the bubble size is 100 nm; and the mixing time is 10 min.

[0055] The cross-flow filtration equipment uses a filter membrane with a pore size of 0.1 μm; an operating pressure of 0.3 MPa; a temperature of 20° C.; a flow rate of 30 L / min; and a filtration time of 20 min.

[0056] The specific operation of the plasma modification treatment of the filter membrane used in the cross-flow filtration equipment is as follows:

[0057] T1: First, pre-treat the filter membrane by immersing it in an ethanol solution, adding 1% by weight of bisindolemaleimide (CAS: 137592-45-1) and 2% by weight of 2-amino-1,3,5-triazine in ethanol, and soaking at 60°C for 3 hours. Then, remove and air-dry.

[0058] T2: The filter membrane pretreated in step T1 is then placed in the reaction chamber of the plasma treatment equipment. After the reaction chamber is sealed, the pressure in the reaction chamber is pumped down to 10 Pa, and a mixture of ammonia and argon is introduced into the reaction chamber.

[0059] T3: After the treatment is completed, turn off the plasma generator, stop introducing ammonia and argon, slowly introduce air into the reaction chamber to restore the pressure to normal pressure, then remove the filter membrane, rinse it twice with deionized water, dry it until it is free of moisture, and then add it to the cross-flow filtration equipment for use.

[0060] The volume ratio of ammonia to argon is 1:2.

[0061] The flow rate of the mixed gas is controlled at 50 sccm, so that the pressure in the reaction chamber is maintained at 50 Pa.

[0062] The plasma generator is set to have a power of 100W and a processing time of 5 minutes.

[0063] Example 2

[0064] A method for preparing hydroxylamine hydrochloride by ketoxime hydrolysis, the operating steps are:

[0065] S1: 33g of ketoxime and 30g of hydrochloric acid solution were pretreated in a pressurized nanobubble fluidized bed, heated, and then subjected to reactive distillation, during which the by-product butanone was continuously distilled off;

[0066] S2: After the reaction is completed, the mixed solution is frozen to precipitate, and then filtered through a cross-flow filtration device to obtain hydroxylamine hydrochloride crystals;

[0067] S3: The filtrate is concentrated by vacuum distillation and cold precipitation, and repeated three times to obtain hydroxylamine hydrochloride crystals and crystallization mother liquor;

[0068] S4: The crystallization mother liquor is returned to the reactor to continue the hydrolysis reaction;

[0069] The filter membrane used in the cross-flow filtration equipment is prepared by pre-treatment with bisindolemaleimide and 2-amino-1,3,5-triazine and then plasma treatment.

[0070] The ketoxime is butanone oxime.

[0071] The mass concentration of the hydrochloric acid solution is 32%.

[0072] The reaction temperature of S1 is 65° C. and the reaction time is 70 min.

[0073] The pressurized nanobubble fluidized bed needs to continuously introduce nitrogen to generate nanobubbles to promote mass transfer; the nitrogen flow rate is 2 L / min; the bubble size is 200 nm; and the mixing time is 15 min.

[0074] The cross-flow filtration equipment uses a filter membrane with a pore size of 0.2 μm; an operating pressure of 0.4 MPa; a temperature of 25° C.; a flow rate of 35 L / min; and a filtration time of 30 min.

[0075] The specific operation of the plasma modification treatment of the filter membrane used in the cross-flow filtration equipment is as follows:

[0076] T1: First, pretreat the filter membrane by immersing it in an ethanol solution, adding 2% by weight of bisindolemaleimide (CAS: 137592-45-1) and 3% by weight of 2-amino-1,3,5-triazine in ethanol, and soaking at 65°C for 4 hours. Then, remove and air-dry.

[0077] T2: The filter membrane pretreated in step T1 is then placed in the reaction chamber of the plasma treatment equipment. After the reaction chamber is sealed, the pressure in the reaction chamber is pumped down to 15 Pa, and a mixture of ammonia and argon is introduced into the reaction chamber.

[0078] T3: After the treatment is completed, turn off the plasma generator, stop introducing ammonia and argon, slowly introduce air into the reaction chamber to restore the pressure to normal pressure, then remove the filter membrane, rinse it twice with deionized water, dry it until it is free of moisture, and then add it to the cross-flow filtration equipment for use.

[0079] The volume ratio of ammonia to argon is 1:2.

[0080] The flow rate of the mixed gas is controlled at 60 sccm, so that the pressure in the reaction chamber is maintained at 60 Pa.

[0081] The plasma generator is set to have a power of 110 W and a processing time of 6 minutes.

[0082] Example 3

[0083] A method for preparing hydroxylamine hydrochloride by ketoxime hydrolysis, the operating steps are:

[0084] S1: 38g of ketoxime and 34g of hydrochloric acid solution were pretreated in a pressurized nanobubble fluidized bed, heated, and then subjected to reactive distillation, during which the by-product butanone was continuously distilled off;

[0085] S2: After the reaction is completed, the mixed solution is frozen to precipitate, and then filtered through a cross-flow filtration device to obtain hydroxylamine hydrochloride crystals;

[0086] S3: The filtrate is concentrated by vacuum distillation and cold precipitation, and repeated three times to obtain hydroxylamine hydrochloride crystals and crystallization mother liquor;

[0087] S4: The crystallization mother liquor is returned to the reactor to continue the hydrolysis reaction;

[0088] The filter membrane used in the cross-flow filtration equipment is prepared by pre-treating with bisindolemaleimide and 2-amino-1,3,5-triazine and then undergoing plasma treatment.

[0089] The ketoxime is butanone oxime.

[0090] The mass concentration of the hydrochloric acid solution is 34%.

[0091] The reaction temperature of S1 is 65° C. and the reaction time is 80 min.

[0092] The pressurized nanobubble fluidized bed needs to be continuously fed with nitrogen to generate nanobubbles to promote mass transfer; the nitrogen flow rate is 2 L / min; the bubble size is 200 nm; and the mixing time is 25 min.

[0093] The cross-flow filtration equipment uses a filter membrane with a pore size of 0.4 μm; an operating pressure of 0.5 MPa; a temperature of 25° C.; a flow rate of 45 L / min; and a filtration time of 40 min.

[0094] The specific operation of the plasma modification treatment of the filter membrane used in the cross-flow filtration equipment is as follows:

[0095] T1: First, pre-treat the filter membrane by immersing it in an ethanol solution, adding 4% by weight of bisindolemaleimide CAS: 137592-45-1 in ethanol, and 5% by weight of 2-amino-1,3,5-triazine in ethanol, and soaking at 65°C for 5 hours, then taking it out and drying it;

[0096] T2: The filter membrane pretreated in step T1 is then placed in the reaction chamber of the plasma treatment equipment. After the reaction chamber is sealed, the pressure in the reaction chamber is pumped down to 15 Pa, and a mixture of ammonia and argon is introduced into the reaction chamber.

[0097] T3: After the treatment is completed, turn off the plasma generator, stop introducing ammonia and argon, slowly introduce air into the reaction chamber to restore the pressure to normal pressure, then remove the filter membrane, rinse it with deionized water three times, dry it until it is free of moisture, and then add it to the cross-flow filtration equipment for use.

[0098] The volume ratio of ammonia to argon is 1:3.

[0099] The flow rate of the mixed gas is controlled at 70 sccm, so that the pressure in the reaction chamber is maintained at 90 Pa.

[0100] The plasma generator is set to have a power of 140W and a processing time of 8 minutes.

[0101] Example 4

[0102] A method for preparing hydroxylamine hydrochloride by ketoxime hydrolysis, the operating steps are:

[0103] S1: 40g of ketoxime and 38g of hydrochloric acid solution were pretreated in a pressurized nanobubble fluidized bed, heated, and then subjected to reactive distillation, during which the by-product cyclohexanone was continuously distilled off;

[0104] S2: After the reaction is completed, the mixed solution is frozen to precipitate, and then filtered through a cross-flow filtration device to obtain hydroxylamine hydrochloride crystals;

[0105] S3: The filtrate is concentrated by vacuum distillation and cold precipitation, and repeated three times to obtain hydroxylamine hydrochloride crystals and crystallization mother liquor;

[0106] S4: The crystallization mother liquor is returned to the reactor to continue the hydrolysis reaction;

[0107] The filter membrane used in the cross-flow filtration equipment is prepared by pre-treating with bisindolemaleimide and 2-amino-1,3,5-triazine and then undergoing plasma treatment.

[0108] The ketoxime is cyclohexanone oxime.

[0109] The mass concentration of the hydrochloric acid solution is 35%.

[0110] The reaction temperature of S1 is 70° C. and the reaction time is 90 min.

[0111] The pressurized nanobubble fluidized bed needs to continuously introduce nitrogen to generate nanobubbles to promote mass transfer; the nitrogen flow rate is 3 L / min; the bubble size is 300 nm; and the mixing time is 30 min.

[0112] The cross-flow filtration equipment uses a filter membrane with a pore size of 0.5 μm; an operating pressure of 0.6 MPa; a temperature of 30° C.; a flow rate of 50 L / min; and a filtration time of 50 min.

[0113] The specific operation of the plasma modification treatment of the filter membrane used in the cross-flow filtration equipment is as follows:

[0114] T1: First, pretreat the filter membrane by immersing it in an ethanol solution, adding 5% by weight of bisindolemaleimide (CAS: 137592-45-1) and 6% by weight of 2-amino-1,3,5-triazine in ethanol, and soaking at 70°C for 6 hours. Then, remove and air-dry.

[0115] T2: The filter membrane pretreated in step T1 is then placed in the reaction chamber of the plasma treatment equipment. After the reaction chamber is sealed, the pressure in the reaction chamber is pumped down to 20 Pa, and a mixture of ammonia and argon is introduced into the reaction chamber.

[0116] T3: After the treatment is completed, turn off the plasma generator, stop introducing ammonia and argon, slowly introduce air into the reaction chamber to restore the pressure to normal pressure, then remove the filter membrane, rinse it with deionized water three times, dry it until it is free of moisture, and then add it to the cross-flow filtration equipment for use.

[0117] The volume ratio of ammonia to argon is 1:3.

[0118] The flow rate of the mixed gas is controlled at 80 sccm, so that the pressure in the reaction chamber is maintained at 100 Pa.

[0119] The plasma generator is set to have a power of 150W and a processing time of 10 minutes.

[0120] Comparative Example 1

[0121] The filter membrane was not subjected to plasma modification treatment, and the other procedures were the same as in Example 1.

[0122] Comparative Example 2

[0123] No bisindolemaleimide was added during the plasma modification of the filter membrane, and the other procedures were the same as in Example 1.

[0124] Comparative Example 3

[0125] During the plasma modification treatment of the filter membrane, 2-amino-1,3,5-triazine was not added, and the other procedures were the same as in Example 1.

[0126] Table 1: Test results

[0127]

[0128]

[0129] Through the data analysis of the above examples and comparative examples, the hydroxylamine hydrochloride prepared by the present invention has high purity and yield, and low chroma.

[0130] The above description is merely a preferred embodiment of the present invention and does not constitute any form of limitation to the present invention. Although the present invention has been disclosed as above in terms of a preferred embodiment, it is not intended to limit the present invention. Any person skilled in the art can, without departing from the scope of the technical solution of the present invention, make some changes or modifications to equivalent embodiments using the technical contents disclosed above. However, any brief modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. A method for preparing hydroxylamine hydrochloride by ketoxime hydrolysis, the operating steps are: S1: Pre-treating 30-40 parts of ketoxime and 26-38 parts of hydrochloric acid solution by weight in a pressurized nanobubble fluidized bed, heating, and then performing reactive distillation, during which the by-product ketone is continuously distilled off; S2: After the reaction is completed, the mixed solution is frozen to precipitate, and then filtered through a cross-flow filtration device to obtain hydroxylamine hydrochloride crystals; S3: The filtrate is concentrated by vacuum distillation and cold precipitation, and repeated three times to obtain hydroxylamine hydrochloride crystals and crystallization mother liquor; S4: The crystallization mother liquor is returned to the reactor to continue the hydrolysis reaction. The filter membrane used in the cross-flow filtration equipment is prepared by pre-treating with bisindolemaleimide and 2-amino-1,3,5-triazine and then undergoing plasma treatment.

2. The method for preparing hydroxylamine hydrochloride by ketoxime hydrolysis according to claim 1, wherein: The ketoxime is one of acetone oxime, butanone oxime and cyclohexanone oxime.

3. The method for preparing hydroxylamine hydrochloride by ketoxime hydrolysis according to claim 1, wherein: The mass concentration of the hydrochloric acid solution is 30-35%.

4. The method for preparing hydroxylamine hydrochloride by ketoxime hydrolysis according to claim 1, wherein: The reaction temperature of S1 is 60-70°C, and the reaction time is 60-90 minutes.

5. The method for preparing hydroxylamine hydrochloride by ketoxime hydrolysis according to claim 1, characterized in that: The pressurized nanobubble fluidized bed needs to continuously introduce nitrogen to generate nanobubbles to promote mass transfer; the nitrogen flow rate is 1-3 L / min; the bubble size is 100-300 nm; and the mixing time is 10-30 min.

6. The method for preparing hydroxylamine hydrochloride by ketoxime hydrolysis according to claim 1, wherein: The cross-flow filtration equipment uses a filter membrane with a pore size of 0.1-0.5 μm; an operating pressure of 0.3-0.6 MPa; a temperature of 20-30° C.; a flow rate of 30-50 L / min; and a filtration time of 20-50 min.

7. The method for preparing hydroxylamine hydrochloride by ketoxime hydrolysis according to claim 1, characterized in that: The specific operation of the plasma modification treatment of the filter membrane used in the cross-flow filtration equipment is as follows: T1: First, pretreat the filter membrane by immersing it in an ethanol solution, adding 1-5% by weight of bisindolemaleimide and 2-6% by weight of 2-amino-1,3,5-triazine in ethanol, and soaking at 60-70°C for 3-6 hours, then taking it out and drying it; T2: The filter membrane pretreated in step T1 is then placed in the reaction chamber of the plasma treatment equipment. After the reaction chamber is sealed, the pressure in the reaction chamber is pumped down to 10-20 Pa, and a mixture of ammonia and argon is introduced into the reaction chamber. T3: After the treatment is completed, turn off the plasma generator, stop introducing ammonia and argon, slowly introduce air into the reaction chamber to restore the pressure to normal pressure, then remove the filter membrane, rinse it with deionized water 2-3 times, dry it until it is free of moisture, and then add it to the cross-flow filtration equipment for use.

8. The method for preparing hydroxylamine hydrochloride by ketoxime hydrolysis according to claim 7, characterized in that: The volume ratio of ammonia to argon is 1:2-1:

3.

9. The method for preparing hydroxylamine hydrochloride by ketoxime hydrolysis according to claim 7, characterized in that: The flow rate of the mixed gas is controlled at 50-80 sccm, so that the pressure in the reaction chamber is maintained at 50-100 Pa.

10. The method for preparing hydroxylamine hydrochloride by ketoxime hydrolysis according to claim 7, characterized in that: The plasma generator is set to have a power of 100-150W and a processing time of 5-10 minutes.

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