Novel method for synthesizing bisamide podand

Abstract

The invention discloses a novel method for synthesizing bisamide podand, and belongs to the field of organic synthesis. The method comprises the following steps: directly reacting diglycolic acid with secondary amine, carrying out gradient heating and reaction rate control in the reaction process, carrying out rotary evaporation, petroleum ether dilution and filtration after the reaction is finished, adding excessive nitric acid to generate a third phase, filtering and taking out the third phase, and carrying out petroleum ether washing, alkali washing, water washing and vacuum drying to obtain the bisamide podand. The method has the advantages of milder reaction conditions, few reaction steps, short reaction time, simple purification steps and higher purity and yield.

Description

Technical Field

[0001] The present invention relates to the technical field of organic synthesis, and particularly relates to a new method for synthesizing bisamide podands. Background Art

[0002] After spent fuel is processed by the PUREX process, a large amount of U and Pu are recovered, while highly radioactive and highly toxic high-level radioactive waste liquid is generated. In addition to a small amount of unextracted U and Pu, the high-level radioactive waste liquid also contains minor actinides (such as Am, Np, Cm), a large number of fission product elements (such as Tc, Pd, Zr, I, Cs, Sr), and lanthanide elements, etc. Therefore, the treatment of high-level radioactive waste liquid is an important part of the safe and sustainable development of nuclear energy. At present, the mainstream treatment method for high-level radioactive waste liquid is the separation-transmutation technology, that is, using chemical methods to separate minor actinides and long-lived fission product elements from high-level radioactive waste liquid, and then using or incinerating them in a high-flux reactor or an accelerator-driven subcritical system to achieve transmutation. Through separation-transmutation, the volume and toxicity of high-level radioactive waste liquid can be reduced by about two orders of magnitude. After the separated radioactive waste liquid is solidified, it only needs to be placed in a shallow geological layer for a few hundred years to reduce its radioactive level to the natural background level, greatly improving the safety of high-level radioactive waste liquid treatment. Bisamide podand extractants are one of the hot extractants used in the aqueous treatment of high-level radioactive waste liquid. In liquid-liquid extraction, bisamide podand extractants can selectively extract An(III) and Ln(III) in the aqueous phase. Bisamide podands have the advantages of fast extraction rate, good selectivity, simple method, and mature process. In addition, such extractants only contain C, H, O, and N and can be completely burned, which are clean extractants.

[0003] There are three main synthesis methods for bisamide podand extractants: (1) the reaction of secondary amine and acid ester; (2) the reaction of secondary amine and acyl chloride; (3) the reaction of secondary amine and acid anhydride. The above three methods have problems such as long reaction time, harsh reaction conditions, and many by-products. There is an urgent need for a simple and efficient synthesis method. Summary of the Invention

[0004] The purpose of the present invention is to design a new synthesis scheme to overcome the problems of long reaction time, many steps, and harsh conditions in the existing bisamide podand synthesis scheme.

[0005] The present invention provides a new method for synthesizing bisamide podands, including:

[0006] Step 1: Add diglycolic acid and N-methylpyrrolidine to a container filled with a solvent, and add secondary amine and diphenylsilane to another container filled with a solvent. Place the containers containing different solutions in a constant temperature shaker and shake at a constant temperature;

[0007] Step 2: Pour the shaken different solutions in Step 1 into a microwave synthesis reactor for microwave synthesis reaction;

[0008] Step 3: After the reaction ends, perform rotary evaporation, dilute with petroleum ether, filter, add excessive nitric acid to generate a third phase, and filter out the third phase; after washing with petroleum ether, alkali washing, water washing and vacuum drying, bisamide podand is obtained.

[0009] Further, the secondary amine is diisooctylamine or N-methyloctylamine.

[0010] Further, in Step 1, the solvent is acetonitrile, benzene or deuterated chloroform.

[0011] Further, in Step 1, the molar ratio of diglycolic acid to N-methylpyrrole is 1:1.5 - 3; the molar ratio of the secondary amine to diphenylsilane is 1:1 - 1.5; the molar ratio of diglycolic acid to the secondary amine is 1:2 - 3.

[0012] Further, in Step 1, the constant temperature oscillation temperature is 30 - 60 °C, the oscillation time is 2 h, and the oscillation frequency is 100 - 300 rpm.

[0013] Further, in Step 2, the microwave synthesis reaction is a stepwise temperature increase; in the first stage, the temperature is increased to 30 - 70 °C and held for 1 h, in the second stage, the temperature is increased to 35 - 75 °C and held for 1 h, and in the third stage, the temperature is increased to 40 - 80 °C and the reaction is carried out for 10 h.

[0014] Further, in Step 3, the concentration of the nitric acid is 3 - 4 mol / L.

[0015] Further, in Step 3, the vacuum degree of vacuum drying is -0.08 MPa, the temperature is 60 - 70 °C, and the drying time is 8 - 12 h.

[0016] The beneficial effects of the present invention are as follows:

[0017] A new method for synthesizing bisamide podand of the present invention directly reacts diglycolic acid and secondary amine through stepwise temperature increase during the whole reaction process to complete the synthesis of bisamide podand extractant. In this method, the activation reaction of diglycolic acid and secondary amine and the microwave synthesis reaction maintain a gradient temperature increase mode between the two processes, and the temperature rises gently; this method has the advantages of milder reaction conditions, fewer reaction steps, shorter reaction time, simpler purification steps and higher yield. Description of the Drawings

[0018] Figure 1 is a flow chart provided by the present invention;

[0019] Figure 2 for TEHDGA prepared by the method of Example 1 of the present invention

[0019] , Figure 1 , , Figure 2 , 1 , ,

[0018] 1H-NMR spectrum;

[0020] Figure 3 1H-NMR spectrum of DMDODGA prepared by the method of Example 2 of the present invention 1 1H-NMR spectrum. Detailed implementation manners

[0021] The present invention will be further described below with reference to the accompanying drawings.

[0022] Add diglycolic acid and N-methylpyrrolidine to the solvent in a molar ratio of 1:1.5 to 3. Take the corresponding amount of diglycolic acid according to the molar ratio of diglycolic acid to secondary amine of 1:2 to 3. Take the corresponding amount of the drug according to the molar ratio of secondary amine to diphenylsilane of 1:1 to 1.5 and add it to another bottle of solvent. Then keep it warm and shake for 2 h at 30 to 60 °C, and the shaking frequency is 100 to 300 rpm;

[0023] (2) After the heat preservation is completed, mix the two bottles of solutions and add them to a microwave reaction kettle, put it into a microwave synthesizer, and heat it up step by step. Slowly heat it up to 30 °C in the first stage and keep it warm for 1 h, heat it up to 35 °C in the second stage and keep it warm for 1 h, and heat it up to 40 to 80 °C in the third stage and react for 10 h.

[0024] (3) Take out the product from the microwave synthesizer, carry out reduced pressure distillation (-0.08 MPa, stop when no liquid flows into the collecting bottle during rotary evaporation), disperse it with petroleum ether to form a suspension, filter it, contact it with a large amount of 3 to 4 mol / l nitric acid to form a third phase, filter it, and wash the third phase by means of petroleum ether, alkali washing, deionized water washing, etc. Finally, obtain a yellow oily substance, and vacuum dry it at -0.08 MPa and 60 to 70 °C for 8 to 12 h to obtain the product.

[0025] Example 1

[0026] Add diglycolic acid and N-methylpyrrolidone into a conical flask according to a molar ratio of 1:2, add 50 ml of acetonitrile as a diluent, and label it as 1. Add diisooctylamine and diphenylsilane into another conical flask according to a molar ratio of 1:1, and label it as 2. (The molar ratio of diglycolic acid to diisooctylamine is 1:2 to 2.5, and the concentration of diglycolic acid after mixing the two should be less than 0.1 mol / L.) Place 1 and 2 in a constant temperature oscillator and keep oscillating at 40 °C and 200 rpm for 2 h to fully activate the reactants. After the oscillation ends, transfer the solutions in the two conical flasks into a microwave reaction kettle. Set a gradient temperature increase. In the first stage, slowly heat up to 30 °C and keep it warm for 1 h. In the second stage, heat up to 35 °C and keep it warm for 1 h. In the third stage, heat up to 40 °C and keep it warm for 10 h. After the reaction ends, wait for the equipment to cool down to room temperature, transfer the product into a pear-shaped flask, and perform vacuum distillation at -0.08 MPa and 60 °C. End when no more liquid is generated in the collection flask. Take out the remaining product in the pear-shaped flask, dilute it with petroleum ether, filter it, and then contact it with a large amount of 3-4 mol / l nitric acid to form a third phase. Filter again, take the yellow viscous oil on the filter paper, wash the third phase by means of petroleum ether, alkali, deionized water washing, etc. to obtain a yellow oil, and finally obtain the product after vacuum drying overnight. The yield is about 60%, and the purity > 95%.

[0027] Example 2

[0028] Add diglycolic acid and N-methylpyrrolidone into a conical flask according to a molar ratio of 1:2, add 50 ml of acetonitrile as a diluent, and label it as 1. Add N-methyloctylamine and diphenylsilane into another conical flask according to a molar ratio of 1:1, and label it as 2. (The molar ratio of diglycolic acid to N-methyloctylamine is 1:2 to 2.5, and the concentration of diglycolic acid after mixing the two should be less than 0.1 mol / L.) Place 1 and 2 in a constant temperature oscillator and keep oscillating at 35 °C and 200 rpm for 2 h to fully activate the reactants. After the oscillation ends, transfer the solutions in the two conical flasks into a microwave reaction kettle. Set a gradient temperature increase. In the first stage, slowly heat up to 30 °C and keep it warm for 1 h. In the second stage, heat up to 35 °C and keep it warm for 1 h. In the third stage, heat up to 40 °C and keep it warm for 10 h. After the reaction ends, wait for the equipment to cool down to room temperature, transfer the product into a pear-shaped flask, and at this time, the solution in the reaction kettle is yellow. Then perform vacuum distillation at -0.08 MPa and 60 °C. End when no more liquid is generated in the collection flask. Take out the remaining product in the pear-shaped flask, dilute it with petroleum ether, filter it, and then contact it with a large amount of 3-4 mol / l nitric acid to form a third phase. Filter again, take the yellow viscous oil on the filter paper, wash the third phase by means of petroleum ether, alkali, deionized water washing, etc. to obtain a yellow oil, and finally obtain the product after vacuum drying overnight. The yield is about 57%, and the purity > 95%.

[0029] Comparative Example 1

[0030] Add diglycolic acid and N-methylpyrrolidone into a conical flask according to a molar ratio of 1:2, add 50 ml of acetonitrile as a diluent, and label it as 1. Add N-methyloctylamine and diphenylsilane into another conical flask according to a molar ratio of 1:1, and label it as 2. (The molar ratio of diglycolic acid to N-methyloctylamine is 1:2 to 2.5, and the concentration of diglycolic acid after mixing the two should be less than 0.1 mol / L.) Place 1 and 2 in a constant temperature oscillator and keep oscillating at 35 °C and 200 rpm for 2 h to fully activate the reactants. After the oscillation ends, transfer the solutions in the two conical flasks to a microwave reactor. Directly heat up to 60 °C and keep warm for 10 h. After the reaction ends, wait for the equipment to cool down to room temperature, transfer the product to a pear-shaped flask. At this time, the solution in the reactor shows dark brown or black. If directly heated to a higher temperature, the reaction will be too intense, resulting in side reactions and the failure of the reaction, that is, the solution in the reactor shows dark brown or black.

[0031] In summary, the present invention has developed a simpler and more efficient synthesis method for bisamide podand extractants. By directly reacting diglycolic acid with secondary amines in a microwave synthesis manner, the reaction steps and reaction time are greatly reduced. And with fewer reactants, it is easier to obtain a purer product, which has greater advantages compared with traditional synthesis methods.

[0032] The above-described embodiments are only used to describe the preferred mode of the present invention, and do not limit the scope of the present invention. Without departing from the design spirit of the present invention, various deformations and improvements made by those of ordinary skill in the art to the technical solution of the present invention should fall within the protection scope determined by the claims of the present invention.

Claims

1. A new method for synthesizing bisamide podand, characterized in that, Including: Step 1: Add diglycolic acid and N-methylpyrrolidone into a container filled with a solvent, and add a secondary amine and diphenylsilane into another container filled with a solvent. Place the containers containing different solutions in a constant temperature shaker and shake at a constant temperature. Step 2: Pour the shaken different solutions in Step 1 into a microwave synthesis reactor for microwave synthesis reaction. Step 3: After the reaction is completed, perform rotary evaporation, dilute with petroleum ether, filter, add an excessive amount of nitric acid to form a third phase, and filter out the third phase. After washing with petroleum ether, alkali washing, water washing and vacuum drying, a bisamide podand is obtained.

2. The new method for synthesizing bisamide podand according to claim 1, characterized in that, In Step 1, the solvent is acetonitrile, benzene, deuterated chloroform.

3. The new method for synthesizing bisamide podand according to claim 1, characterized in that, In Step 1, the molar ratio of diglycolic acid to N-methylpyrrole is 1:1.5 - 3; the molar ratio of the secondary amine to diphenylsilane is 1:1 - 1.5; the molar ratio of diglycolic acid to the secondary amine is 1:2 - 3.

4. The new method for synthesizing bisamide podand according to claim 1, characterized in that, In Step 1, the constant temperature shaking temperature is 30 - 60 °C, the shaking time is 2 h, and the shaking frequency is 100 - 300 rpm.

5. The new method for synthesizing bisamide podand according to claim 1, characterized in that, In Step 2, the microwave synthesis reaction is a stepwise temperature increase; in the first stage, the temperature is raised to 30 - 70 °C and kept warm for 1 h, in the second stage, the temperature is raised to 35 - 75 °C and kept warm for 1 h, and in the third stage, the temperature is raised to 40 - 80 °C and reacted for 10 h.

6. The new method for synthesizing bisamide podand according to claim 1, characterized in that, In Step 3, the concentration of the nitric acid is 3 - 4 mol / L.

7. The new method for synthesizing bisamide podand according to claim 1, characterized in that, In Step 3, the vacuum degree of vacuum drying is -0.08 MPa, the temperature is 60 - 70 °C, and the drying time is 8 - 12 h.

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