Preparation method of diisopropanol hydroxylamine

Abstract

A preparation method of diisopropanolamine comprises the following steps: S1, mixing and dissolving excessive diisopropanolamine and a solvent, heating, dropwise adding hydrogen peroxide, and oxidizing the diisopropanolamine with the hydrogen peroxide to obtain a reaction solution; s2, after the reaction liquid is cooled to the room temperature, introducing carbon dioxide gas, forming carbonate with excessive diisopropanolamine, enabling the carbonate to enter a water phase, and retaining a target product in an oil phase; s3, carrying out reduced pressure distillation after oil-water separation to obtain the diisopropyl hydroxylamine. After the oxidation reaction is finished, CO2 is introduced into the system to form diisopropanolamine carbonate with excessive diisopropanolamine, the diisopropanolamine carbonate enters a water phase, a target product is retained in an oil phase, the hydroxylamine product is separated after standing and liquid separation, an extraction agent is not needed, the whole reaction process is reversible, the raw material amine is recycled, the production process is simple, the energy consumption is low, and the method is suitable for industrial production. The selectivity and yield of diisopropyl hydroxylamine can reach 90% or above, and the problem that the synthesized target product diisopropyl hydroxylamine is difficult to separate from excessive amine is solved.

Description

Technical Field

[0001] The invention relates to the technical field of organic synthesis, in particular to a method for preparing diisopropanol hydroxylamine. Background Art

[0002] Diisopropylhydroxylamine is an important fine chemical, usually referred to as HPHA. It is widely used in the field of styrene inhibition due to its excellent inhibitory effect on olefins. In addition, due to its strong reducing property, it can be used in the production of antioxidants and as a boiler descaling agent.

[0003] The traditional separation method (CN110508021A) is to acid hydrolyze, concentrate, cool and crystallize the crude product after the reaction is completed to obtain solid isopropylhydroxylamine salt, redissolve the solid isopropylhydroxylamine salt, neutralize with alkali, and distill to obtain isopropylhydroxylamine solution. The solubility of isopropylhydroxylamine increases with the increase of temperature. The sudden decrease in temperature at the condenser causes supersaturation of isopropylhydroxylamine in the fraction. The precipitated isopropylhydroxylamine crystals gradually accumulate and easily block the pipeline. In addition, due to the high volatility of the product, the product is easily incompletely collected under vacuum distillation, resulting in a low yield.

[0004] At present, the separation method after the synthesis of diisopropyl hydroxylamine is relatively simple. For the reaction with the addition of a catalyst, CN117304066A and CN115724762B disclose that the catalyst is separated first, and then the reaction solvent and unreacted diisopropyl hydroxylamine are removed by vacuum distillation to obtain a diisopropyl hydroxylamine product; and CN117342973A discloses a method for preparing diisopropyl hydroxylamine by catalyst-free catalysis, that is, anhydride and hydrogen peroxide are used as oxidants, and the oxidation product obtained after the reaction is contacted with an extraction solvent for solvent extraction, the obtained extract is anhydride and an organic solvent, the obtained raffinate is a hydrophilic solvent and dihydroxypropyl hydroxylamine, and the raffinate is subjected to vacuum distillation to remove the hydrophilic solvent to obtain a dihydroxypropyl hydroxylamine product. Vacuum distillation is indeed an effective separation technology, especially suitable for the separation of heat-sensitive or high-boiling-point substances. The physical properties of diisopropyl hydroxylamine and diisopropyl hydroxylamine are similar, but their boiling points and volatility are slightly different, so they can be separated by vacuum distillation in theory. However, some specific factors need to be considered in actual operation. The boiling point of diisopropanolamine and dihydroxypropylhydroxylamine is slightly different, so it may not be possible to completely separate the two compounds. In addition, vacuum distillation has the disadvantages of high equipment cost, complex operation, high energy consumption, and limited separation efficiency. Summary of the invention

[0005] The technical problem to be solved by the present invention is that the traditional separation method of diisopropanol hydroxylamine, which is synthesized and then dehydrated by multiple salting out to break the azeotrope to obtain a high-content diisopropanol hydroxylamine, has the problems of cumbersome operation, large loss and difficulty in treating waste salt, which leads to the problem that the whole process is not economical and has poor competitiveness. A preparation method of diisopropanol hydroxylamine is provided, which has the advantages of simple production process, low energy consumption and high separation efficiency, can effectively reduce production costs and improve economic benefits.

[0006] In order to solve the above technical problems, the technical concept of the present invention is to use organic ester solvents and low-concentration H2O2 as an oxidant to directly oxidize diisopropanolamine, specifically and selectively synthesize diisopropanolhydroxylamine. After the reaction is completed, CO2 is introduced into the system to form carbonate with excess diisopropanolamine. After standing and separating the liquids, the hydroxylamine product is separated, and the excess amine is recovered.

[0007] Based on the above technical concept, the present invention specifically includes the following steps: Step S1: after mixing and dissolving an excess of diisopropanolamine and a solvent, adding hydrogen peroxide dropwise at a high temperature, and oxidizing the diisopropanolamine with hydrogen peroxide to obtain a reaction solution; S2, after the reaction liquid is cooled to room temperature, carbon dioxide gas is introduced to form carbonate with excess amine and enter the water phase, and the target product is retained in the oil phase; S3, the oil and water are separated and then distilled under reduced pressure to obtain diisopropylhydroxylamine.

[0008] In step S1, the solvent is an ester organic solvent, selected from one or more of isopropyl acetate, tert-butyl acetate, triacetin and ethyl acetate; preferably ethyl acetate. The mass ratio of diisopropanolamine to the solvent is 1.3:1.6 ~ 2.6:0.3. The mass concentration of the hydrogen peroxide solution is 15~50 wt%; the molar ratio of diisopropanolamine to hydrogen peroxide is 2.0 ~4.25:1. Preferably, the hydrogen peroxide solution is added dropwise to the diisopropanolamine solution at a rate of 0.100mL / min ~ 0.652mL / min; the reaction time of diisopropanolamine and hydrogen peroxide solution at 30℃~70℃ is 5min ~ 40min; preferably, the reaction temperature is 50℃~70℃, and the reaction time is 5min ~ 40min.

[0009] Since the reaction solution obtained in step S1 is a mixed solution of diisopropanolamine, diisopropanol hydroxylamine, solvent and water, wherein the boiling point of diisopropanolamine is about 230°C, and the boiling point of dihydroxypropyl hydroxylamine is about 215°C, at normal pressure, their boiling point difference is small, in addition, these two compounds have certain heat sensitivity, and direct distillation will affect the quality of the compound. Since the reactants and products have similar physical properties, the present invention, after the reaction of step S1 is completed, CO2 is introduced into the reaction solution obtained in step 1 to form diisopropanolamine carbonate with excess diisopropanolamine, and the separation of hydroxylamine products is achieved by vacuum distillation after standing and separating the liquids, and diisopropanolamine can also be recycled at the same time.

[0010] In step S2, the object to be processed is cooled to 10-30°C; preferably cooled to 20-30°C; In step S2, the rate of introducing carbon dioxide gas is 15 mL / min to 120 mL / min; preferably, the rate of introducing carbon dioxide is 120 mL / min; The time for introducing carbon dioxide in step S2 is 120 min to 960 min; preferably, the time for introducing carbon dioxide is 120 min; In the method provided by the present invention, in step S2, during the process of introducing carbon dioxide, stirring is performed while introducing the carbon dioxide, and the stirring rate is 600 rpm to 1000 rpm; preferably, the stirring rate is 1000 rpm; In step S2, the pressure is normal pressure.

[0011] The standing separation time after the carbon dioxide is passed in step S2 is 15 min to 90 min; preferably, the standing separation time is 60 min.

[0012] In step S2, the solution after the carbon dioxide is introduced is light yellow, and its components include diisopropanolamine, diisopropanolhydroxylamine, solvent and water.

[0013] According to the present invention, after carbon dioxide is introduced into the material to be treated, diisopropanolamine forms carbonate, thereby increasing the property difference between diisopropanolamine and diisopropanol hydroxylamine, and facilitating extraction with ethyl acetate and then concentration to obtain a diisopropanol hydroxylamine product.

[0014] During the reduced pressure distillation in step S3, the vacuum pressure is -1 MPa~0 MPa, the temperature is 25°C~50°C, and the time is 0.5h~3h.

[0015] In step S3, there is no need to introduce an additional extractant, and the reaction solvent can achieve separation and extraction, with high separation efficiency, effectively reducing production costs.

[0016] The present invention has the following advantages: 1. After the oxidation reaction is completed, CO2 is introduced into the system to form diisopropanolamine carbonate with excess diisopropanolamine and enter the water phase, and the target product is retained in the oil phase. After standing and separating the liquids, the hydroxylamine product is separated. No extraction agent is required to separate the hydroxylamine product. The whole reaction process is reversible, and the raw material amine is recycled. The production process is simple, the energy consumption is low, and the separation efficiency is high. The selectivity and yield of diisopropanol hydroxylamine can reach more than 90%, which effectively reduces the production cost and improves the economic benefit. The method has important practical value and broad application prospects.

[0017] 2. The problem of difficulty in separating the target product diisopropylhydroxylamine from the excess amine has been effectively solved. Diisopropylhydroxylamine and diisopropylhydroxylamine have similar structures and physical properties, and are both easily soluble in water. Direct extraction cannot separate the two. DETAILED DESCRIPTION

[0018] The technical solution of the present invention is described in detail and clearly below. It should be understood that the specific implementation methods described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0019] In the method provided by the present invention, after carbon dioxide is introduced into the object to be treated and the organic phase contains diisopropanolhydroxylamine and a solvent after extraction, the aqueous phase is water and unreacted diisopropanolamine, wherein the organic phase is concentrated to obtain a diisopropanolhydroxylamine product. Example 1

[0020] The yield is the actual product mass obtained / theoretical product mass obtained × 100%, based on hydrogen peroxide The selectivity is the actual mass of product obtained / theoretical mass of product obtained × 100%, with the consumption of diisopropanolamine as the standard.

[0021] The recovery rate is the actual mass of diisopropanolamine obtained / theoretical mass of product × 100% Example 2

[0022] In a reaction vessel, 25 g of diisopropanolamine and 4 g of ethyl acetate were heated and mixed to dissolve. After the temperature was raised to 60°C, 6 g of 30 wt% hydrogen peroxide was added dropwise at a rate of 0.313 mL / min. The addition time was 13.48 min. The reaction was terminated when the addition was completed. After the reaction was completed, the solution was cooled to 30°C, and carbon dioxide was introduced into the solution at a rate of 120 mL / min, while stirring at a stirring rate of 1000 rpm. After the gas was introduced for 120 min, the solution was allowed to stand for 60 min. The reaction solution was divided into oil-water phases. Under a vacuum pressure of -0.1 MPa, the solution was concentrated to obtain 7.62 g of diisopropanol hydroxylamine, with a yield of 96.4% and a selectivity of 99.7%. 17.4 g of diisopropanolamine was obtained, with a recovery rate of 99.2%. Example 3

[0023] In a reaction vessel, 50 g of diisopropanolamine and 8 g of ethyl acetate were heated and mixed to dissolve. After the temperature was raised to 60°C, 12 g of 30 wt% hydrogen peroxide was added dropwise at a rate of 0.313 mL / min. The addition time was 26.96 min. The reaction was terminated when the addition was completed. After the reaction was completed, the solution was cooled to 30°C, and carbon dioxide was introduced into the solution at a rate of 120 mL / min, while stirring at a stirring rate of 1000 rpm. After the gas was introduced for 120 min, the solution was allowed to stand for 60 min. The reaction solution was divided into oil-water phases. Under a vacuum pressure of -0.1 MPa, 15.04 g of diisopropanol hydroxylamine was obtained by concentration, with a yield of 95.5% and a selectivity of 99.8%. 34.69 g of diisopropanolamine was obtained, with a recovery rate of 99.3%. Example 4

[0024] In a reaction vessel, 125 g of diisopropanolamine and 20 g of ethyl acetate were heated and mixed to dissolve. After the temperature was raised to 60°C, 30 g of 30 wt% hydrogen peroxide was added dropwise at a rate of 0.313 mL / min for 96 min. After the addition was completed, the reaction was continued for 10 min. After the reaction was completed, the solution was cooled to 30°C, and carbon dioxide was introduced into the solution at a rate of 120 mL / min, while stirring at a stirring rate of 1000 rpm. After the gas was introduced for 120 min, the solution was allowed to stand for 60 min, and the reaction solution was divided into oil-water phases. Under a vacuum pressure of -0.1 MPa, 37.62 g of diisopropanol hydroxylamine was obtained by concentration, with a yield of 95.4% and a selectivity of 99.7%. 86.61 g of diisopropanolamine was obtained, and the recovery rate was 99.1%. Example 5

[0025] In a reaction vessel, 125 g of diisopropanolamine and 20 g of ethyl acetate were heated and mixed to dissolve. After the temperature was raised to 60°C, 30 g of 30 wt% hydrogen peroxide was added dropwise at a rate of 0.313 mL / min for 96 min. The reaction was continued for 10 min after the addition was completed. After the reaction was completed, the solution was cooled to 30°C, and carbon dioxide was introduced into the solution at a rate of 15 mL / min, while stirring at a stirring rate of 1000 rpm. After the gas was introduced for 960 min, the solution was allowed to stand for 60 min, and the reaction solution was divided into oil-water phases. Under a vacuum pressure of -0.1 MPa, 36.14 g of diisopropanol hydroxylamine was obtained by concentration, with a yield of 91.6%, a selectivity of 83.1%, and 86.40 g of diisopropanolamine with a recovery rate of 99.0%. Example 6

[0026] In a reaction container, 125 g of diisopropanolamine and 20 g of ethyl acetate were heated and mixed to dissolve. After the temperature was raised to 60°C, 30 g of 30 wt% hydrogen peroxide was added dropwise at a rate of 0.313 mL / min for 96 min. After the addition was completed, the reaction was continued for 10 min. After the reaction was completed, the solution was cooled to 20°C, and carbon dioxide was introduced into the solution at a rate of 120 mL / min while stirring at a stirring rate of 1000 rpm. After the gas was introduced for 120 min, the solution was allowed to stand for 60 min, and the reaction solution was separated into oil-water phases. Under a vacuum pressure of -0.1 MPa, 36.85 g of diisopropanol hydroxylamine was obtained by concentration, with a yield of 93.4% and a selectivity of 96.5%. 86.25 g of diisopropanolamine was obtained, and the recovery rate was 98.8%.

[0027] Example 6 In a reaction vessel, 125 g of diisopropanolamine and 20 g of tert-butyl acetate were heated and mixed to dissolve. After the temperature was raised to 60 ° C, 30 g of 30 wt% hydrogen peroxide was added dropwise at a rate of 0.313 mL / min, and the addition time was 96 min. After the addition was completed, the reaction was continued for 10 min. After the reaction was completed, it was cooled to 30 ° C, and carbon dioxide was introduced into the solution at a rate of 120 mL / min, while stirring, and the stirring rate was 1000 rpm; after the gas was introduced for 120 min, it was allowed to stand for 60 min, and the reaction solution was divided into oil and water phases. Under a vacuum pressure of -0.1 MPa, 36.34 g of diisopropanol hydroxylamine was concentrated, with a yield of 92.1%, a selectivity of 99.4%, and 88.46 g of diisopropanolamine was obtained, with a recovery rate of 99.0%. Example 7

[0028] In a reaction vessel, 125 g of diisopropanolamine and 20 g of isopropyl acetate were heated and mixed to dissolve. After the temperature was raised to 60°C, 30 g of 30 wt% hydrogen peroxide was added dropwise at a rate of 0.313 mL / min for 96 min. The reaction was continued for 10 min after the addition was completed. After the reaction was completed, the solution was cooled to 30°C, and carbon dioxide was introduced into the solution at a rate of 15 mL / min, while stirring at a stirring rate of 1000 rpm. After the gas was introduced for 960 min, the solution was allowed to stand for 60 min. The reaction solution was divided into oil-water phases. Under a vacuum pressure of -0.1 MPa, 34.96 g of diisopropanol hydroxylamine was obtained by concentration, with a yield of 88.6% and a selectivity of 77.34%. 80.83 g of diisopropanolamine was obtained, and the recovery rate was 99.0%. Example 8

[0029] In a reaction container, 125 g of diisopropanolamine and 20 g of triacetin were heated and mixed to dissolve. After the temperature was raised to 60°C, 30 g of 30 wt% hydrogen peroxide was added dropwise at a rate of 0.313 mL / min for 96 min. After the addition was completed, the reaction was continued for 10 min. After the reaction was completed, the solution was cooled to 20°C, and carbon dioxide was introduced into the solution at a rate of 120 mL / min while stirring at a stirring rate of 1000 rpm. After the gas was introduced for 120 min, the reaction solution was allowed to stand for 60 min, and the reaction solution was separated into oil-water phases. Under a vacuum pressure of -0.1 MPa, 33.68 g of diisopropanol hydroxylamine was obtained by concentration, with a yield of 85.4% and a selectivity of 86.0%. 86.17 g of diisopropanolamine was obtained, and the recovery rate was 99.0%.

Claims

1. A method for preparing diisopropylhydroxylamine, characterized in that The steps include: Step S1: after dissolving an excess of diisopropanolamine and a solvent, heating and dripping hydrogen peroxide, the diisopropanolamine is oxidized by hydrogen peroxide to obtain a reaction solution; Step S2, after the reaction liquid is cooled to room temperature, carbon dioxide gas is introduced to form carbonate with excess diisopropanolamine and enter the water phase, and the target product is retained in the oil phase; Step S3, separating the oil and water and distilling under reduced pressure to obtain diisopropylhydroxylamine.

2. The method for preparing diisopropylhydroxylamine according to claim 1, characterized in that In step S1, the solvent is an ester organic solvent, selected from one or more of isopropyl acetate, tert-butyl acetate, triacetin and ethyl acetate; preferably ethyl acetate.

3. The method for preparing the diisopropylhydroxylamine aqueous solution as claimed in claim 1, characterized in that In step S1, the mass ratio of diisopropanolamine to the solvent is 1.3:1.6 ~ 2.6:0.3; the mass concentration of the hydrogen peroxide solution is 15~50wt%; the molar ratio of diisopropanolamine to hydrogen peroxide is 2.0~4.25:1; the hydrogen peroxide solution is added dropwise to the diisopropanolamine solution at a rate of 0.100mL / min~0.652mL / min; the reaction time of diisopropanolamine and hydrogen peroxide solution at 30°C~70°C is 5min~40min; preferably, the reaction temperature is 50°C~70°C, and the reaction time is 5min~40min.

4. The method for preparing the diisopropylhydroxylamine aqueous solution as claimed in claim 1, characterized in that In step S2, the reaction solution is cooled to 10-30°C; preferably to 20-30°C.

5. The method for preparing the diisopropylhydroxylamine aqueous solution as claimed in claim 1, characterized in that In step S2, the rate of introducing carbon dioxide gas is 15 mL / min to 120 mL / min; preferably, the rate of introducing carbon dioxide is 120 mL / min; the time of introducing carbon dioxide is 120 min to 960 min; preferably, the time of introducing carbon dioxide is 120 min.

6. The method for preparing the diisopropylhydroxylamine aqueous solution as claimed in claim 1, characterized in that Step S2 is performed under normal pressure.

7. The method for preparing the diisopropylhydroxylamine aqueous solution as claimed in claim 1, characterized in that In step S2, during the process of introducing carbon dioxide, stirring is performed while introducing the carbon dioxide, and the stirring rate is 600 rpm to 1000 rpm; preferably, the stirring rate is 1000 rpm.

8. The method for preparing the diisopropylhydroxylamine aqueous solution as claimed in claim 1, characterized in that In step S2, after the carbon dioxide is completely discharged, the standing and separation time is 15 min to 90 min; preferably, the standing and separation time is 60 min.

9. The method for preparing the diisopropylhydroxylamine aqueous solution as claimed in claim 1, characterized in that In step S2, the solution after the carbon dioxide is introduced is light yellow, and its components include diisopropanolamine, diisopropanolhydroxylamine, solvent and water.

10. The method for preparing the diisopropylhydroxylamine aqueous solution as claimed in claim 1, characterized in that During the reduced pressure distillation in step S3, the vacuum pressure is -1 MPa~0 MPa, the temperature is 25°C~50°C, and the time is 0.5h~3h.