A method for preparing hydroxylamine aqueous solution using microchannel technology

Abstract

The invention discloses a method for preparing a hydroxylamine aqueous solution using microchannel technology, and belongs to the technical field of preparing hydroxylamine aqueous solution. Specifically, the method pumps nitric acid solution and acid solution into a microchannel reactor, and then adds 2 6% of the total mass of the system as a palladium resin catalyst, and hydrogen enters the microchannel reactor through a pipeline, and the reactor performs a hydroxylamine reaction at a set temperature and a hydrogen partial pressure to prepare a hydroxylamine salt solution; after the hydroxylamine salt solution is recovered as a catalyst, an alkali solution is added for neutralization reaction, and after the reaction is completed, suction filtration and reduced pressure distillation are performed, and the fraction is a hydroxylamine aqueous solution. The method significantly improves the mass transfer between the raw material gas, liquid and solid by microchannel technology, which is of great significance for the improvement of the selectivity of the hydroxylamine solution.

Description

Technical Field

[0001] The invention relates to the technical field of hydroxylamine aqueous solution preparation, in particular to a method for preparing hydroxylamine aqueous solution by utilizing microchannel technology. Background Art

[0002] Hydroxylamine salts or hydroxylamine are a kind of fine chemical products with a wide range of uses. Hydroxylamine has the molecular formula of NH2OH. It is an unstable white crystal at room temperature, easily deliquescent and easily decomposed. Therefore, hydroxylamine is usually stored, transported and used in the form of aqueous solution or salt. Hydroxylamine salts are mainly compounds formed by inorganic acids and hydroxylamine, such as hydroxylamine hydrochloride, hydroxylamine sulfate, hydroxylamine phosphate and hydroxylamine nitrate.

[0003] The application document "Method for preparing hydroxylamine salt / hydroxylamine by reaction extraction coupling" with publication number CN104129765B provides a method for preparing hydroxylamine salt / hydroxylamine in one step by coupling technology of oxime hydrolysis reaction and solvent extraction. Oxime (ketoxime or aldoxime) is used as raw material, and the hydrolysis reaction of oxime in acidic solution is coupled with organic solvent extraction separation. During the hydrolysis reaction, the extractant extracts the corresponding ketone or aldehyde into the organic phase, thereby breaking the limitation of the chemical equilibrium of the oxime hydrolysis reaction under milder conditions, so that the reaction proceeds in the direction of generating hydroxylamine salt / hydroxylamine, thereby achieving the purpose of improving the reaction conversion rate and the yield of hydroxylamine salt / hydroxylamine.

[0004] The application document "An Industrial Mass Production Method for Producing High-Purity Hydroxylamine" with publication number CN115707796A has the following basic features: it includes the following production steps: preparation of raw materials, treatment of raw materials, preparation of buffer system, addition of electrolyte, generation of hydroxylamine, purification of hydroxylamine and continuous preparation of hydroxylamine. The industrial mass production method for producing high-purity hydroxylamine is provided with a special precision filter element and resin filtering method to remove tiny impurity particles and metal ions in the raw materials, reduce the influence of tiny impurity particles on the reduction reaction, and improve product quality. The electrochemical reaction is carried out through a bipolar continuous electrolysis technology system, which is conducive to controlling the purity of hydroxylamine, improving the control ability and conversion rate of the hydroxylamine reduction reaction, and increasing the production capacity of the enterprise. The ion membrane clean electrochemical production system through the ion exchange membrane can reduce the generation of by-product salts to achieve the purpose of continuous production, and the hydroxylamine is purified through the exchange membrane to improve the purity of the hydroxylamine.

[0005] The application document "A method for preparing hydroxylamine using nitrogen" with publication number CN110482505B relates to a method for preparing free hydroxylamine solution by electrolysis and electrodialysis. The method comprises: nitrogen stored in a nitrogen storage device enters water stored in a water storage device through a first pipeline, and the humidified nitrogen enters a discharge reaction chamber through a second pipeline; a high voltage power supply is turned on, a high voltage is applied to the discharge array needle plate, and water radical cation clusters are generated at the needle tip of the discharge array needle plate, and the formed water radical cation clusters react with nitrogen to produce hydroxylamine radical cations and nitroxyl, and the hydroxylamine radical cations are transferred to the cathode plate to form hydroxylamine; the hydroxylamine formed on the cathode plate is output and collected through a product output channel.

[0006] Based on the above-mentioned technical data on the preparation of hydroxylamine, it can be found that in the process of preparing hydroxylamine, the mass transfer between the gas, liquid and solid of the raw materials is poor, which affects the selectivity of the reaction, resulting in a lack of hydroxylamine concentration and poor economic benefits. Summary of the invention

[0007] The present invention aims to provide a method for preparing a hydroxylamine aqueous solution using microchannel technology to solve at least one of the technical problems in the above technical background, improve the gas-liquid-solid mass transfer efficiency in the reaction process, improve the reaction selectivity, and increase the hydroxylamine concentration.

[0008] Another object of the present invention is to provide an aqueous solution of hydroxylamine prepared by the above method.

[0009] The purpose of the present invention is achieved through the following technical solutions:

[0010] A method for preparing a hydroxylamine aqueous solution using microchannel technology, the operating steps are:

[0011] S1: Pump 2-10 parts of nitric acid solution and 2-5 parts of acid solution into the microchannel reactor by mass, then add 2-6% of the total mass of the system as a palladium resin catalyst, hydrogen enters the microchannel reactor through a pipeline, and the reactor performs a hydroxylamine reaction at a set temperature and hydrogen partial pressure to prepare a hydroxylamine salt solution;

[0012] S2: After the catalyst is recovered from the hydroxylamine salt solution in step S1, an alkali solution is added to carry out a neutralization reaction. After the reaction is completed, suction filtration and reduced pressure distillation are performed to obtain a hydroxylamine aqueous solution.

[0013] In some embodiments of the present invention, the acid solution in S1 is at least one of sulfuric acid, hydrochloric acid or phosphoric acid, and the concentration of the acid solution is 5-25wt%.

[0014] In some embodiments of the present invention, the reaction temperature of the microchannel reactor in S1 is 45-65° C., and the hydrogen partial pressure is 45-65%.

[0015] In some embodiments of the present invention, the preparation method of the palladium resin catalyst in S1 is:

[0016] A1: According to weight, polystyrene bonded methyl isocyanate is crushed into 400-700 meshes, and 100-150 parts of polystyrene bonded methyl isocyanate (CAS: 59990-69-1), 14-28 parts of 2-amino-5-mercapto-1,3,4-thiadiazole, 1000-1400 parts of ethylene dichloride, and 3-6 parts of stannous octoate are added into the reactor, and the reaction is carried out at 50-60℃ for 50-100 minutes;

[0017] A2: Add 21-42 parts of allylcyclopentadienylpalladium (CAS: 1271-03-0) and 2-5 parts of triethylamine by weight, react at 50-60°C for 100-140 minutes, filter, and dry to form a palladium resin catalyst.

[0018] In some embodiments of the present invention, the ratio of the inner diameter of the microchannel reactor to the average particle size of the palladium resin catalyst is 10-15.

[0019] In some embodiments of the present invention, the reaction temperature in S2 is -15 to 15°C, and the reaction time is 0.5-2h.

[0020] In some embodiments of the present invention, the vacuum distillation temperature in S2 is 50-65° C., and the vacuum distillation pressure is 0.01-0.1 MPa.

[0021] In some embodiments of the present invention, the alkali solution in S2 is selected from at least one of sodium hydroxide solution, potassium hydroxide solution or ammonia water, the molar ratio of the alkali to the hydroxylamine salt is 1:0.8-1.5, and the molar amount of the alkali is calculated as hydroxide.

[0022] The preparation principle of the above-mentioned palladium resin catalyst is:

[0023] Polystyrene-bonded methyl isocyanate undergoes a condensation reaction with the amino group of 2-amino-5-mercapto-1,3,4-thiadiazole to obtain an intermediate A; the mercapto group then undergoes an addition reaction with allylcyclopentadienylpalladium to obtain a resin catalyst containing thiadiazole and cyclopentadienylpalladium; the selectivity of the hydrogenation reaction to prepare hydroxylamine can be improved.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] 1. The mass transfer between gas, liquid and solid among the raw materials is significantly improved, which improves the selectivity of the reaction;

[0026] 2. Thiadiazole is a heterocyclic compound with strong electron-donating ability. It can form an effective coordination with the palladium catalyst, thereby optimizing the activity and selectivity of the catalyst. As another important component of the catalyst, the cyclopentadiene group can effectively reduce the occurrence of side reactions due to its large steric hindrance effect, thereby improving the selectivity of the reaction. At the same time, the cyclopentadiene group may also act as a hydrogen acceptor, promoting the hydrogen transfer process, thereby improving the catalytic efficiency. DETAILED DESCRIPTION

[0027] The essential features and significant effects of the present invention can be reflected from the following embodiments, but they do not limit the present invention in any way, and those skilled in the art can make some non-essential improvements and adjustments based on the content of the present invention. The present invention is further described below through specific implementation methods.

[0028] Hydroxylamine selectivity = hydroxylamine output / nitrate consumption × 100%.

[0029] Catalyst activity = the amount of hydroxylamine produced per gram of palladium resin catalyst per unit time.

[0030] The concentration of hydroxylamine aqueous solution was determined by potassium permanganate method.

[0031] Example 1

[0032] A method for preparing a hydroxylamine aqueous solution using microchannel technology, the operating steps are:

[0033] S1: 2 kg of nitric acid solution and 2 kg of acid solution are pumped into the microchannel reactor, and then 2% of the total mass of the system is added as a palladium resin catalyst, and hydrogen enters the microchannel reactor through a pipeline. The reactor performs a hydroxylamine reaction at a set temperature and hydrogen partial pressure to prepare a hydroxylamine salt solution;

[0034] S2: After the catalyst is recovered from the hydroxylamine salt solution in step S1, an alkali solution is added to carry out a neutralization reaction. After the reaction is completed, suction filtration and reduced pressure distillation are performed to obtain a hydroxylamine aqueous solution.

[0035] The acid solution in S1 is sulfuric acid, and the concentration of the acid solution is 5wt%.

[0036] The reaction temperature of the microchannel reactor in S1 is 45° C., and the hydrogen partial pressure is 45%.

[0037] The preparation method of the palladium resin catalyst in S1 is:

[0038] A1: Polystyrene bonded methyl isocyanate was crushed into 400 mesh; 100g polystyrene bonded methyl isocyanate, 14g 2-amino-5-mercapto-1,3,4-thiadiazole, 1000g ethylene dichloride, 3g stannous octoate were added into the reactor, and the reaction was carried out at 50°C for 50min;

[0039] A2: Add 21 g of allylcyclopentadienylpalladium (CAS: 1271-03-0) and 2 g of triethylamine, react at 50°C for 100 min, filter, and dry to form a palladium resin catalyst.

[0040] The ratio of the inner diameter of the microchannel reactor to the average particle diameter of the palladium resin catalyst is 10.

[0041] The reaction temperature in S2 is -15°C and the reaction time is 0.5h.

[0042] The vacuum distillation temperature in S2 is 50° C., and the vacuum distillation pressure is 0.01 MPa.

[0043] The alkali solution in S2 is selected from sodium hydroxide solution, the molar ratio of the alkali to the hydroxylamine salt is 1:0.8, and the molar amount of the alkali is calculated as hydroxide.

[0044] Example 2

[0045] A method for preparing a hydroxylamine aqueous solution using microchannel technology, the operating steps are:

[0046] S1: 5 kg of nitric acid solution and 3 kg of acid solution are pumped into the microchannel reactor, and then 3% of the total mass of the system is added as a palladium resin catalyst, and hydrogen enters the microchannel reactor through a pipeline. The reactor performs a hydroxylamine reaction at a set temperature and hydrogen partial pressure to prepare a hydroxylamine salt solution;

[0047] S2: After the catalyst is recovered from the hydroxylamine salt solution in step S1, an alkali solution is added to carry out a neutralization reaction. After the reaction is completed, suction filtration and reduced pressure distillation are performed to obtain a hydroxylamine aqueous solution.

[0048] The acid solution in S1 is at least one of sulfuric acid, hydrochloric acid or phosphoric acid, and the concentration of the acid solution is 10wt%.

[0049] The reaction temperature of the microchannel reactor in S1 is 50° C. and the hydrogen partial pressure is 50%.

[0050] The preparation method of the palladium resin catalyst in S1 is:

[0051] A1: Polystyrene bonded methyl isocyanate was crushed into 500 mesh, 115g polystyrene bonded methyl isocyanate, 18g 2-amino-5-mercapto-1,3,4-thiadiazole, 1100g ethylene dichloride, 4g stannous octoate were added into the reactor, and the reaction was carried out at 55°C for 75min;

[0052] A2: Add 28 g of allylcyclopentadienylpalladium (CAS: 1271-03-0) and 3 g of triethylamine, react at 55°C for 115 min, filter, and dry to form a palladium resin catalyst.

[0053] The ratio of the inner diameter of the microchannel reactor to the average particle diameter of the palladium resin catalyst is 12.

[0054] The reaction temperature in S2 is -5°C and the reaction time is 1 h.

[0055] The vacuum distillation temperature in S2 is 55° C., and the vacuum distillation pressure is 0.04 MPa.

[0056] The alkali solution in S2 is selected from at least one of sodium hydroxide solution, potassium hydroxide solution or ammonia water, the molar ratio of the alkali to the hydroxylamine salt is 1:1.0, and the molar amount of the alkali is calculated as hydroxide.

[0057] Example 3

[0058] A method for preparing a hydroxylamine aqueous solution using microchannel technology, the operating steps are:

[0059] S1: 8 kg of nitric acid solution and 4 kg of acid solution are pumped into the microchannel reactor, and then 5% of the total mass of the system is added as a palladium resin catalyst, and hydrogen enters the microchannel reactor through a pipeline. The reactor performs a hydroxylamine reaction at a set temperature and hydrogen partial pressure to prepare a hydroxylamine salt solution;

[0060] S2: After the catalyst is recovered from the hydroxylamine salt solution in step S1, an alkali solution is added to carry out a neutralization reaction. After the reaction is completed, suction filtration and reduced pressure distillation are performed to obtain a hydroxylamine aqueous solution.

[0061] The acid solution in S1 is hydrochloric acid, and the concentration of the acid solution is 20wt%.

[0062] The reaction temperature of the microchannel reactor in S1 is 60° C., and the hydrogen partial pressure is 60%.

[0063] The preparation method of the palladium resin catalyst in S1 is:

[0064] A1: Polystyrene bonded methyl isocyanate was crushed into 600 mesh; 140g polystyrene bonded methyl isocyanate, 24g 2-amino-5-mercapto-1,3,4-thiadiazole, 1300g ethylene dichloride, 5g stannous octoate were added into the reactor, and the reaction was carried out at 55°C for 80min;

[0065] A2: Add 35 g of allylcyclopentadienylpalladium (CAS: 1271-03-0) and 4 g of triethylamine, react at 55°C for 130 min, filter, and dry to form a palladium resin catalyst.

[0066] The ratio of the inner diameter of the microchannel reactor to the average particle diameter of the palladium resin catalyst is 13.

[0067] The reaction temperature in S2 is 5° C. and the reaction time is 1.5 h.

[0068] The vacuum distillation temperature in S2 is 60° C., and the vacuum distillation pressure is 0.08 MPa.

[0069] The alkali solution in S2 is selected from potassium hydroxide solution, the molar ratio of the alkali to the hydroxylamine salt is 1:1.2, and the molar amount of the alkali is calculated as hydroxide.

[0070] Example 4

[0071] A method for preparing a hydroxylamine aqueous solution using microchannel technology, the operating steps are:

[0072] S1: 10 kg of nitric acid solution and 5 kg of acid solution are pumped into the microchannel reactor, and then 6% of the total mass of the system is added as a palladium resin catalyst, and hydrogen enters the microchannel reactor through a pipeline. The reactor performs a hydroxylamine reaction at a set temperature and hydrogen partial pressure to prepare a hydroxylamine salt solution;

[0073] S2: After the catalyst is recovered from the hydroxylamine salt solution in step S1, an alkali solution is added to carry out a neutralization reaction. After the reaction is completed, suction filtration and reduced pressure distillation are performed to obtain a hydroxylamine aqueous solution.

[0074] The acid solution in S1 is phosphoric acid, and the concentration of the acid solution is 25wt%.

[0075] The reaction temperature of the microchannel reactor in S1 is 65° C., and the hydrogen partial pressure is 65%.

[0076] The preparation method of the palladium resin catalyst in S1 is:

[0077] A1: Polystyrene bonded methyl isocyanate was crushed into 700 mesh; 150g polystyrene bonded methyl isocyanate (CAS: 59990-69-1), 28g 2-amino-5-mercapto-1,3,4-thiadiazole, 1400g ethylene dichloride, 6g stannous octoate were added into the reactor, and the reaction was carried out at 60°C for 100min;

[0078] A2: Add 42 g of allylcyclopentadienylpalladium (CAS: 1271-03-0) and 5 g of triethylamine, react at 60°C for 140 min, filter, and dry to form a palladium resin catalyst.

[0079] The ratio of the inner diameter of the microchannel reactor to the average particle diameter of the palladium resin catalyst is 15.

[0080] The reaction temperature in S2 is 15° C. and the reaction time is 2 h.

[0081] The vacuum distillation temperature in S2 is 65° C., and the vacuum distillation pressure is 0.1 MPa.

[0082] The alkali solution in S2 is selected from aqueous ammonia, and the molar ratio of the alkali to the hydroxylamine salt is 1:1.5, and the molar amount of the alkali is calculated as hydroxide.

[0083] Comparative Example 1

[0084] In this example, 2-amino-5-mercapto-1,3,4-thiadiazole was not added during the preparation of the palladium resin catalyst, and the rest was consistent with Example 1.

[0085] Comparative Example 2

[0086] In this example, no stannous octoate was added during the preparation of the palladium resin catalyst, and the rest was the same as in Example 1.

[0087] The test results of the above embodiments and comparative examples are shown in the following table:

[0088] project Hydroxylamine selectivity % Catalyst activity g hydroxylamine / hour / g palladium Hydroxylamine solution concentration mol / L Example 1 87.7 28.7 2.34 Example 2 90.1 30.5 2.77 Example 3 90.4 30.8 2.56 Example 4 91.2 31.6 2.64 Comparative Example 1 81.0 18.8 2.22 Comparative Example 2 84.3 23.6 2.30

[0089] It can be seen from the above specific implementation methods that the mass transfer effect between raw materials is improved by microchannel technology, and the selectivity of hydroxylamine is improved. At the same time, the catalyst prepared by this method has an excellent catalytic effect.

[0090] The preferred specific embodiments of the present invention are described in detail above. It should be understood that ordinary technicians in the field can make many modifications and changes based on the concept of the present invention without creative work. Therefore, all technical solutions that can be obtained by technicians in the technical field based on the concept of the present invention through logical analysis, reasoning or limited experiments on the basis of the prior art should be within the scope of protection determined by the claims.

Claims

1. A method for preparing a hydroxylamine aqueous solution using microchannel technology, the operating steps of which are: S1: Pump 2-10 parts of nitric acid solution and 2-5 parts of acid solution into the microchannel reactor by mass, then add 2-6% of the total mass of the system as a palladium resin catalyst, hydrogen enters the microchannel reactor through a pipeline, and the reactor performs a hydroxylamine reaction at a set temperature and hydrogen partial pressure to prepare a hydroxylamine salt solution; S2: After the catalyst is recovered from the hydroxylamine salt solution in step S1, an alkali solution is added to carry out a neutralization reaction. After the reaction is completed, suction filtration and reduced pressure distillation are performed to obtain a hydroxylamine aqueous solution; The preparation method of the palladium resin catalyst in S1 is: A1: According to weight, polystyrene bonded methyl isocyanate is crushed into 400-700 meshes, 100-150 parts of polystyrene bonded methyl isocyanate, 14-28 parts of 2-amino-5-mercapto-1,3,4-thiadiazole, 1000-1400 parts of ethylene dichloride, 3-6 parts of stannous octoate are added into the reactor, and the reaction is carried out at a temperature of 50-60°C for 50-100 minutes; A2: Add 21-42 parts of allylcyclopentadienylpalladium and 2-5 parts of triethylamine by weight, react at 50-60°C for 100-140 minutes, filter, and dry to form a palladium resin catalyst.

2. The method for preparing a hydroxylamine aqueous solution using microchannel technology according to claim 1, characterized in that: The acid solution in S1 is at least one of sulfuric acid, hydrochloric acid or phosphoric acid, and the concentration of the acid solution is 5-25wt%.

3. The method for preparing a hydroxylamine aqueous solution using microchannel technology according to claim 1, characterized in that: The reaction temperature of the microchannel reactor in S1 is 45-65° C., and the hydrogen partial pressure is 45-65%.

4. The method for preparing a hydroxylamine aqueous solution using microchannel technology according to claim 1, characterized in that: The ratio of the inner diameter of the microchannel reactor to the average particle diameter of the palladium resin catalyst is 10-15.

5. The method for preparing a hydroxylamine aqueous solution using microchannel technology according to claim 1, characterized in that: The reaction temperature in S2 is -15 to 15°C, and the reaction time is 0.5 to 2 hours.

6. The method for preparing a hydroxylamine aqueous solution using microchannel technology according to claim 1, characterized in that: The vacuum distillation temperature in S2 is 50-65° C., and the vacuum distillation pressure is 0.01-0.1 MPa.

7. The method for preparing a hydroxylamine aqueous solution using microchannel technology according to claim 1, characterized in that: The alkali solution in S2 is selected from at least one of sodium hydroxide solution, potassium hydroxide solution or ammonia water, and the molar ratio of the alkali to the hydroxylamine salt is 1:0.8-1.5, and the molar amount of the alkali is calculated as hydroxide.