Method for preparing diisopropanol hydroxylamine

Abstract

The invention relates to a method for preparing diisopropanolamine. The method comprises the following steps: S1, mixing and dissolving diisopropanolamine and a solvent; s2, under the condition that the temperature is 30-70 DEG C, hydrogen peroxide is dropwise added for an oxidation reaction; and S3, carrying out extraction and separation to obtain diisopropanolamine and diisopropyl hydroxylamine products. According to the invention, tert-butyl acetate is used as a solvent to innovatively construct an oil-water phase reaction system, and the dissolvability difference of tert-butyl acetate and tert-butyl acetate is utilized to skillfully limit the reaction in a water phase, so that a product easy to oxidize stably exists in an oil phase, and the problem of excessive oxidation is effectively solved. The green H2O2 is used as an oxidizing agent to directly oxidize the diisopropanolamine, so that the diisopropanolamine can be specifically and selectively synthesized, the reaction conditions required by the whole production process are mild, no other byproducts are produced except that water is generated by decomposing hydrogen peroxide, the problems of harsh reaction conditions, low yield, environmental pollution and the like in the traditional synthesis method are avoided, and the method is suitable for industrial production. Compared with the prior art, the method is environment-friendly, low in cost and high in yield; the reaction rate is effectively controlled through a method of dropwise adding hydrogen peroxide, the dropwise adding time is the reaction time, the reaction is finished after dropwise adding is finished, and the reaction is efficient.

Description

Technical Field

[0001] The invention relates to the field of organic synthesis, and in particular to a method for preparing dihydroxypropylhydroxylamine. 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] At present, there are very few reports on the synthesis of diisopropylhydroxylamine, and only a few patent reports. The technical route of the relevant patents is introduced below. CN106957240A discloses a method for synthesizing hydroxypropylhydroxylamine, which is mainly prepared by a two-step method, that is, first using hydroxylamine salt and alkali solution to prepare hydroxylamine free base, and then adding propylene oxide to the above hydroxylamine free base to synthesize hydroxypropylhydroxylamine. The above synthesis method has the following defects: (1) The two-step synthesis reaction is highly dangerous, because hydroxylamine free base is a highly reactive substance, which is prone to decomposition or even explosion in the presence of heat and dust, and has great safety hazards; because the free hydroxylamine generated in the first step is unstable, it needs to be carried out in an ice water bath. The reaction between hydroxylamine salt and alkali solution will release a large amount of heat, which may cause hydroxylamine decomposition and reduce the yield. The reaction temperature of propylene oxide needs to be about 20°C, and it needs to be heated, which may also cause a certain amount of hydroxylamine loss. (2) The product yield is not mentioned in the disclosed content, and the reaction time is relatively long, which needs further improvement.

[0004] US6028225 discloses a method for synthesizing dihydroxypropylhydroxylamine using 50% hydroxylamine free base and propylene oxide as raw materials. This method also has defects: (1) the decomposition and explosion safety hazard of hydroxylamine free base and the intrinsic safety of the process is poor; (2) the use of 50% hydroxylamine free base as a raw material has the disadvantages of few suppliers and high price; (3) the product yield is also not mentioned.

[0005] CN112159333A discloses an improved method, i.e., propylene oxide and hydroxylamine salt are added to a solvent in advance and mixed evenly, and then alkali solution is added dropwise, so that the two-step reaction can be completed at one time, avoiding the generation and decomposition of free hydroxylamine, and improving the safety of production and product yield. However, its subsequent purification process still requires extraction and distillation. From the above method, since inorganic bases are used in the process of preparing free hydroxylamine, the inorganic salts and water generated by the inorganic bases and hydroxylamine salts are dissolved in the solution, and it is impossible to directly distill and purify, so extraction and other steps are required for further processing, and the product purification steps are more, which affects the product yield and increases the production cost.

[0006] CN117304066A discloses a method of reacting diisopropanolamine and hydrogen peroxide as main raw materials by catalytic oxidation under the action of titanium silicon molecular sieve catalyst. The specific steps include: first dissolving diisopropanolamine in a specific organic solvent (such as methanol or tert-butyl alcohol), and then carrying out oxidation reaction with a hydrogen peroxide solution in a temperature range of 40°C to 100°C; after the reaction, separating the catalyst by filtering, and removing the unreacted raw materials and solvent by vacuum distillation technology, and finally obtaining a high-purity diisopropanol hydroxylamine product. The environmentally friendly titanium silicon molecular sieve is used as a catalyst, which has good catalytic activity and reusability. Although this method is effective, the product yield is between 48.9% and 89.67%. When using titanium silicon molecular sieve (TS-1) catalyst to catalyze the reaction of diisopropanolamine, although it shows excellent performance in some aspects, it also has problems such as high cost, excessive activity causing diisopropanolamine to be over-oxidized into ammonium nitrate byproducts, and poor stability.

[0007] CN117342973A) discloses a method for preparing diisopropyl alcohol hydroxylamine by catalysis without catalyst, i.e., using anhydride and hydrogen peroxide as oxidants, mixing hydrogen peroxide solution and anhydride to obtain an oxidizing solution, then adding diisopropyl alcohol amine and a solvent mixed solution for oxidation reaction, and finally extracting with an extractant and then distilling under reduced pressure to obtain a dihydroxypropyl hydroxylamine product, with a high yield. However, the reaction of anhydride and hydrogen peroxide is usually a strong exothermic reaction, and unstable peroxides may be generated during the reaction. These peroxides have high oxidizability and explosiveness. If the reaction is improperly controlled, the temperature may rise rapidly, and even cause a fire or explosion.

[0008] Therefore, how to provide a low-cost, high-yield, easy-to-separate and safe method has become an urgent problem to be solved in this field. Summary of the invention

[0009] The problem to be solved by the present invention is the problems existing in the prior art such as over-oxidation, harsh reaction conditions, low yield, environmental pollution, etc.

[0010] In order to solve the above technical problems, the present invention adopts the following technical solutions: A method for preparing diisopropylhydroxylamine comprises the following steps: S1, dissolving diisopropanolamine and a solvent; S2. At a temperature of 30°C to 70°C, add hydrogen peroxide to carry out oxidation reaction; S3. Diisopropanolamine and diisopropanolhydroxylamine products are obtained through extraction and separation.

[0011] The solvent in step S1 is an ester organic solvent, selected from one or more of isopropyl acetate, tert-butyl acetate, triacetin and ethyl acetate; preferably tert-butyl acetate.

[0012] The mass ratio of diisopropanolamine to solvent in S1 is 1.3:1.6 to 2.6:0.3.

[0013] The mass concentration of the hydrogen peroxide solution described in S2 is 15~50 wt%; wherein, the amount of hydrogen peroxide solution added, the molar ratio of diisopropanolamine to hydrogen peroxide is 1:1~2.25.

[0014] Preferably, the hydrogen peroxide solution is added dropwise to the diisopropanolamine solution at a rate of 0.100 mL / min to 0.652 mL / min; In S2, the reaction time of diisopropanolamine and hydrogen peroxide solution at 30°C to 70°C is 5 min to 40 min; preferably, the reaction temperature is 50°C to 70°C, and the reaction time is 5 min to 40 min.

[0015] In the method provided by the present invention, the extractant described in S3 is one or more of ethyl acetate, dichloromethane, chloroform and methanol.

[0016] The extraction described in step S3 is carried out under the following process conditions: at room temperature, the mass ratio of the solvent to the extractant is 1:10 to 60.

[0017] The present invention has the following advantages: 1. Using tert-butyl acetate as solvent, the oil-water phase reaction system is innovatively constructed. Taking advantage of the difference in solubility between the two, the reaction is cleverly limited to the water phase, so that the easily oxidized products can exist stably in the oil phase, effectively solving the problem of over-oxidation. Using green H2O2 (15-50%) as an oxidant to directly oxidize diisopropanolamine can specifically and selectively synthesize diisopropanol hydroxylamine.

[0018] 2. The reaction conditions required for the entire production process are mild. Except for water produced by the decomposition of hydrogen peroxide, there are no other by-products. This avoids the problems of harsh reaction conditions, low yield, and environmental pollution in traditional synthesis methods. Compared with existing technologies, it is green and environmentally friendly, low in cost, and high in yield.

[0019] 3. The reaction rate can be effectively controlled by adding hydrogen peroxide. The dropping time is the reaction time, and the reaction ends when the dropping ends. The reaction is highly efficient. DETAILED DESCRIPTION

[0020] The specific implementation of the present invention is described in detail below. It should be understood that the specific implementation described here is only used to illustrate and explain the present invention, and is not used to limit the present invention. Example 1

[0021] In a reaction vessel, 25 g of diisopropanolamine and 4 g of tert-butyl acetate were heated and mixed to dissolve. After the temperature was raised to 60°C, 21.1 g of 30 wt% hydrogen peroxide was added dropwise at a rate of 0.313 mL / min for 67.4 min. The reaction was completed when the addition was completed. After the reaction was completed, the mixture was cooled to room temperature, 50 mL of ethyl acetate was added, and 26.44 g of diisopropanol hydroxylamine was obtained after extraction and separation with ethyl acetate, with a yield of 94.9% and a selectivity of 99.7%. Example 2

[0022] In a reaction vessel, 25 g of diisopropanolamine and 4 g of ethyl acetate were heated and mixed to dissolve, and the temperature was raised to 60°C. 42.3 g of 30 wt% hydrogen peroxide was added dropwise at a rate of 0.313 mL / min. The addition time was 135.1 min, and the reaction was completed when the addition was completed. After the reaction was completed, the mixture was cooled to room temperature, 50 mL of ethyl acetate was added, and 25.34 g of diisopropanol hydroxylamine was obtained after extraction and separation with ethyl acetate, with a yield of 90.9% and a selectivity of 96.1%. Example 3

[0023] In a reaction vessel, 25 g of diisopropanolamine and 4 g of isopropyl acetate were heated and mixed to dissolve, and the temperature was raised to 60°C. 47.7 g of 30 wt% hydrogen peroxide was added dropwise at a rate of 0.313 mL / min. The addition time was 152.4 min, and the reaction was completed when the addition was completed. After the reaction was completed, the mixture was cooled to room temperature, 50 mL of ethyl acetate was added, and 25.22 g of diisopropanol hydroxylamine was obtained after extraction and separation with ethyl acetate, with a yield of 90.5% and a selectivity of 95.7%. Example 4

[0024] In a reaction vessel, 25 g of diisopropanolamine and 4 g of acetic acid glycerol were heated and mixed to dissolve, and the temperature was raised to 60°C. 31.79 g of 30 wt% hydrogen peroxide was added dropwise at a rate of 0.313 mL / min. The addition time was 101.6 min, and the reaction was completed when the addition was completed. After the reaction was completed, the mixture was cooled to room temperature, 50 mL of ethyl acetate was added, and 25.38 g of diisopropanol hydroxylamine was obtained after extraction and separation with ethyl acetate, with a yield of 91.1% and a selectivity of 96.0%.

[0025] Comparative Example In a reaction container, 13 g of diisopropanolamine, 16 g of methanol, and 2.5 g of titanium silicalite catalyst were heated and mixed to dissolve. After the temperature was raised to 60°C, 3 g of 30 wt% hydrogen peroxide was added dropwise at a rate of 0.313 mL / min for 9.6 min. After the addition was completed, the mixture was reacted for 20 min, cooled to room temperature, and 60 mL of ethyl acetate was added. After extraction and separation with ethyl acetate, 3.418 g of diisopropanolhydroxylamine was obtained with a yield of 85.4% and a selectivity of 89.8%.

Claims

1. A method for preparing diisopropylhydroxylamine, characterized in that The following steps are involved: S1, dissolving diisopropanolamine and a solvent; S2. At a temperature of 30°C to 70°C, add hydrogen peroxide to carry out oxidation reaction; S3. Diisopropanolamine and diisopropanolhydroxylamine products are obtained through extraction and separation.

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

3. The method for preparing diisopropylhydroxylamine according to claim 1, characterized in that In step S1, the solvent is preferably tert-butyl acetate.

4. The method for preparing diisopropylhydroxylamine according to claim 1, characterized in that In step S1, the mass ratio of diisopropylhydroxylamine to solvent is 1.3:1.6 to 2.6:0.

3.

5. The method for preparing diisopropylhydroxylamine according to claim 1, characterized in that The mass concentration of the hydrogen peroxide solution in S2 is 15-50 wt%.

6. The method for preparing diisopropylhydroxylamine according to claim 1, characterized in that The molar ratio of diisopropanolamine to hydrogen peroxide in S2 is 1:1~2.

25.

7. The method of claim 1, wherein the diisopropylhydroxylamine The hydrogen peroxide solution in S2 is added dropwise to the diisopropanolamine solution at a rate of 0.100 mL / min to 0.652 mL / min.

8. The method for preparing diisopropylhydroxylamine according to claim 1, characterized in that The reaction time of diisopropanolamine and hydrogen peroxide solution at 30°C to 70°C in S2 is 0 min to 40 min; preferably, the reaction temperature is 50°C to 70°C.

9. The method for preparing diisopropylhydroxylamine according to claim 1, characterized in that The extractant described in S3 is one or more of ethyl acetate, dichloromethane, chloroform and methanol.

10. The method for preparing diisopropylhydroxylamine according to claim 1, characterized in that The extraction described in S3 is carried out under the following process conditions: at room temperature, the mass ratio of the solvent to the extractant is 1:10 to 60.