A method for preparing bismuth organic acid with moderate reaction conditions

Abstract

The invention relates to the technical field of fine chemical additives, and discloses a method for preparing an organic acid bismuth with moderate reaction conditions. An organic acid ligand has multiple coordination sites, including O atoms on a polycarboxylic acid group, N atoms on an imidazole, and two N atoms provided by two Schiff bases. A benzene ring and an imidazole ring are connected by a C-N single bond, and the two can rotate arbitrarily, so that the organic acid ligand can be suitable for the coordination of various structures, thereby obtaining a stable structure; an ultrasonic-hydrothermal method can be used to quickly heat up and provide a continuous impact force, thereby significantly improving the yield of the organic acid bismuth; an organic acid ligand with multiple coordination sites is synthesized, and screening test conditions are optimized to obtain an organic acid bismuth with high yield and good stability, thereby improving the problem of poor coordination between conventional organic acids and bismuth, and the method has moderate reaction conditions, a short production cycle, and a high utilization rate of a bismuth source, and is suitable for mass production.

Description

Technical Field

[0001] The invention relates to the technical field of fine chemical additives, in particular to a method for preparing organic acid bismuth under moderate reaction conditions. Background Art

[0002] Organic acid bismuth is a new type of non-toxic, green and environmentally friendly catalyst developed in recent years for synthetic resin materials and paint drying agents. It can not only increase the speed of resin synthesis reaction, but also adjust the reaction activity. The prepared resin prepolymer has a narrow molecular weight distribution and a low viscosity. At the same time, this type of catalyst also has the advantages of being non-toxic, harmless, safe and acceptable to the human body. Therefore, it can be widely used in medicine, catalysis and biology to replace the currently used organic tin, lead, mercury heavy metal catalysts with higher toxicity; at the same time, some bismuth complexes have biological functions such as anti-cancer and bactericidal. Therefore, the synthesis of new bismuth complexes is of great significance not only to bioinorganic chemistry, but also to medicine.

[0003] In recent years, there are more and more examples of the application of bismuth and its complexes in organic synthesis, and the scope is becoming wider and wider. At present, many cheap inorganic bismuth salts have been commercialized, but since most Lewis acid metal salts are sensitive to water and easily deliquesced in the air, they need to be processed under dry conditions, and the reaction conditions are relatively harsh. Currently, commonly used organic acid bismuth salt catalysts mainly include isooctanoic acid bismuth salt, neopentanoic acid bismuth salt and cyclohexane acid bismuth salt. In the prior art, a double decomposition synthesis method using water as a solvent is generally used to react an organic acid with a sodium hydroxide solution to prepare an organic acid sodium aqueous solution, which is then reacted with bismuth nitrate to generate an organic acid bismuth. Due to the poor water solubility of the reactant bismuth salt, even under the action of a phase transfer catalyst, the reaction rate is still very slow and it is difficult to react completely. The synthesis process is relatively complicated, the synthesis conditions are required to be high, the production cost is high, and the product yield is low. The organic acid bismuth is prepared by reacting an organic acid with bismuth oxide for a long time under high temperature conditions, which consumes a lot of energy, has a long production cycle, high production cost, and a darker product color, which is not conducive to the long-term development of the enterprise.

[0004] Some bismuth compounds are difficult to synthesize through liquid phase reaction in aqueous solution because the coordination between organic acid and bismuth is poor, resulting in that the inorganic salt of bismuth ion is easily hydrolyzed in aqueous solution. Therefore, the present invention synthesizes organic acid ligands with multiple coordination sites and uses liquid phase coordination reaction to obtain organic acid bismuth, which has high bismuth source utilization and mild reaction conditions. Summary of the invention

[0005] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a method for preparing an organic acid bismuth with mild reaction conditions. The organic acid bismuth has high yield, mild reaction conditions and high bismuth source utilization rate.

[0006] To achieve the above object, the technical solution adopted by the present invention is:

[0007] A method for preparing organic bismuth acid with moderate reaction conditions comprises the following steps:

[0008] (1) In a nitrogen atmosphere, a Schiff base of bisimidazolylaminocarboxylic acid and acetonitrile are added to a reaction flask, and after stirring evenly, bromoacetic acid and potassium carbonate are added, and the mixture is stirred for reaction. After the reaction is completed, the mixture is concentrated under reduced pressure and dried to obtain an organic acid ligand having the structural formula:

[0009] (2) Add bismuth nitrate pentahydrate and deionized water to a reaction flask, stir evenly, add an organic acid ligand, place in an ultrasonic cleaner, stir and react at a power of 20-40 kW, filter after the reaction, and dry to obtain a bismuth organic acid that moderates the reaction conditions.

[0010] Furthermore, in step (1), the ratio of the Schiff base of the bisimidazolylaminocarboxylic acid, acetonitrile, bromoacetic acid, and potassium carbonate is 1 g: (15-25) mL: (0.45-0.55) g: (0.6-0.8) g.

[0011] Furthermore, in step (1), the reaction temperature is 55-70° C. and the reaction time is 1-3 h.

[0012] Furthermore, in step (2), the ratio of bismuth nitrate pentahydrate, deionized water, and organic acid ligand is 1 g: (20-30) mL: (1.1-1.6) g.

[0013] Furthermore, in step (2), the reaction temperature is 40-60° C. and the reaction time is 2-4 h.

[0014] Furthermore, the preparation method of the Schiff base of bisimidazolylaminocarboxylic acid in step (1) comprises the following steps:

[0015] S1. Under a nitrogen atmosphere, 1H-imidazole-4-carboxylic acid, p-fluorobenzaldehyde and N,N-dimethylformamide were added to a reaction flask, stirred evenly, and potassium carbonate was added. After the reaction was completed, the mixture was cooled, extracted with ethyl acetate and deionized water, and the organic phase was concentrated. After separation by column chromatography, the obtained 1-benzaldehyde-imidazole carboxylic acid intermediate had the structural formula:

[0016] S2. Under a nitrogen atmosphere, diethylenetriamine and methanol were added to the reaction flask, and after stirring, 1-benzaldehyde-imidazole carboxylic acid intermediate was added, and the reaction was stirred. After the reaction was completed, the mixture was cooled and filtered, washed with methanol, and concentrated under reduced pressure to obtain a Schiff base of a diimidazole aminocarboxylic acid having the structural formula:

[0017]

[0018] Furthermore, in step S1, the ratio of 1H-imidazole-4-carboxylic acid, p-fluorobenzaldehyde, N,N-dimethylformamide, and potassium carbonate is 1 g: (0.8-0.95) g: (8-12) mL: (1.25-2.05) g.

[0019] Furthermore, in step S1, the reaction temperature is 75-90° C., and the reaction time is 8-16 h.

[0020] Furthermore, in step S2, the ratio of diethylenetriamine, methanol, and 1-benzaldehyde-imidazolecarboxylic acid intermediate is 1 g:(10-15) mL:(3.8-4.2) g.

[0021] Furthermore, in step S2, the reaction temperature is 60-75° C., and the reaction time is 2-5 h.

[0022] By adopting the above technical solution, the beneficial effects of the present invention are:

[0023] The invention firstly reacts 1H-imidazole-4-carboxylic acid with p-fluorobenzaldehyde under the action of potassium carbonate to obtain a 1-benzaldehyde-imidazole carboxylic acid intermediate, then reacts with diethylenetriamine to obtain a bis-imidazolylaminocarboxylic acid Schiff base, then reacts with bromoacetic acid under the action of potassium carbonate to obtain an organic acid ligand, and finally adopts an ultrasonic-hydrothermal method to coordinate with bismuth nitrate pentahydrate to obtain an organic acid bismuth. The reaction conditions are mild and the yield is high.

[0024] The organic acid ligand has coordinating atoms with various coordination abilities, including the O atom on the polycarboxylic acid group, the N atom on the imidazole, and the two N atoms provided by the two Schiff bases. The benzene ring and the imidazole ring are connected by a CN single bond, and the two can rotate arbitrarily, so that the organic acid ligand can be suitable for the coordination of various structures, thereby obtaining a stable structure; the ultrasonic-hydrothermal method is adopted, and the ultrasonic method can quickly heat up and provide continuous impact force, thereby significantly improving the yield of organic acid bismuth.

[0025] By synthesizing an organic acid ligand with multiple coordination sites, an organic acid bismuth with high yield and good stability is obtained, which improves the problems of poor coordination between conventional organic acids and bismuth, difficult synthesis and long reaction time. The reaction conditions of the invention are mild, the production cost is low, the production cycle is short, the bismuth source utilization rate is high, and it is suitable for mass production. DETAILED DESCRIPTION

[0026] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0027] Example 1

[0028] (1) Under nitrogen atmosphere, 5 g of 1H-imidazole-4-carboxylic acid, 4.5 g of p-fluorobenzaldehyde and 50 mL of N,N-dimethylformamide were added to a reaction flask, stirred evenly, and then 3.75 g of potassium carbonate was added. The mixture was reacted at 85° C. for 12 h, cooled, extracted with ethyl acetate and deionized water, and the organic phase was concentrated. After separation by column chromatography, 1-benzaldehyde-imidazole carboxylic acid intermediate was obtained. The preparation reaction formula is as follows:

[0029]

[0030] (2) Under nitrogen atmosphere, 3 g of diethylenetriamine and 35 mL of methanol were added to the reaction flask, and after stirring evenly, 11.85 g of 1-benzaldehyde-imidazole carboxylic acid intermediate was added, and the mixture was reacted at 65° C. for 4 h, cooled and filtered, washed with methanol, and concentrated under reduced pressure to obtain a Schiff base of bis-imidazolylaminocarboxylic acid. The preparation reaction formula is as follows:

[0031]

[0032] (3) Under nitrogen atmosphere, 2.5 g of bisimidazolylaminocarboxylic acid Schiff base and 50 mL of acetonitrile were added to the reaction flask, stirred evenly, and then 1.25 g of bromoacetic acid and 1.7 g of potassium carbonate were added. The mixture was reacted at 65° C. for 2 h, concentrated under reduced pressure, and dried to obtain an organic acid ligand. The preparation reaction formula is as follows:

[0033]

[0034] (4) Add 17.46 g of bismuth nitrate pentahydrate and 435 mL of deionized water to a reaction flask, stir evenly, add 19.21 g of an organic acid ligand, place in an ultrasonic cleaner, react at a power of 20 kW and a temperature of 40° C. for 3 h, filter, and dry to obtain a bismuth organic acid having moderate reaction conditions.

[0035] Example 2

[0036] (1) Under nitrogen atmosphere, 12 g of 1H-imidazole-4-carboxylic acid, 9.6 g of p-fluorobenzaldehyde and 96 mL of N,N-dimethylformamide were added to a reaction flask, stirred evenly, and then 15 g of potassium carbonate was added. The mixture was reacted at 90° C. for 8 h, cooled, extracted with ethyl acetate and deionized water, and the organic phase was concentrated. After separation by column chromatography, 1-benzaldehyde-imidazole carboxylic acid intermediate was obtained.

[0037] (2) Under nitrogen atmosphere, 8 g of diethylenetriamine and 80 mL of methanol were added to a reaction flask, and after stirring, 30.4 g of 1-benzaldehyde-imidazole carboxylic acid intermediate was added, and the mixture was reacted at 75° C. for 2 h, cooled and filtered, washed with methanol, and concentrated under reduced pressure to obtain a bis-imidazolylaminocarboxylic acid Schiff base.

[0038] (3) Under nitrogen atmosphere, 5 g of bisimidazolylaminocarboxylic acid Schiff base and 75 mL of acetonitrile were added to a reaction flask, stirred evenly, and then 2.25 g of bromoacetic acid and 3.8 g of potassium carbonate were added. The mixture was reacted at 70° C. for 1 h, concentrated under reduced pressure, and dried to obtain an organic acid ligand.

[0039] (4) Add 4.85 g of bismuth nitrate pentahydrate and 105 mL of deionized water to a reaction flask, stir evenly, add 5.82 g of an organic acid ligand, place in an ultrasonic cleaner, react at a power of 20 kW and a temperature of 40° C. for 4 h, filter, and dry to obtain a bismuth organic acid having moderate reaction conditions.

[0040] Example 3

[0041] (1) Under nitrogen atmosphere, 25 g of 1H-imidazole-4-carboxylic acid, 23.75 g of p-fluorobenzaldehyde and 300 mL of N,N-dimethylformamide were added to a reaction flask, and after stirring, 51.25 g of potassium carbonate was added, and the mixture was reacted at 75° C. for 16 h. The mixture was cooled, extracted with ethyl acetate and deionized water, and the organic phase was concentrated. After separation by column chromatography, a 1-benzaldehyde-imidazole carboxylic acid intermediate was obtained.

[0042] (2) Under a nitrogen atmosphere, 18 g of diethylenetriamine and 270 mL of methanol were added to a reaction flask, and after stirring, 75.6 g of 1-benzaldehyde-imidazole carboxylic acid intermediate was added, and the mixture was reacted at 60° C. for 5 h, cooled and filtered, washed with methanol, and concentrated under reduced pressure to obtain a bis-imidazolylaminocarboxylic acid Schiff base.

[0043] (3) Under nitrogen atmosphere, 12 g of a Schiff base of a diimidazole aminocarboxylic acid and 300 mL of acetonitrile were added to a reaction flask. After stirring, 6.6 g of bromoacetic acid and 9.68 g of potassium carbonate were added. The mixture was reacted at 55° C. for 3 h, concentrated under reduced pressure, and dried to obtain an organic acid ligand.

[0044] (4) Add 7.76 g of bismuth nitrate pentahydrate and 230 mL of deionized water to a reaction flask, stir evenly, add 10.09 g of an organic acid ligand, place in an ultrasonic cleaner, react at a power of 20 kW and a temperature of 40° C. for 2 h, filter, and dry to obtain a bismuth organic acid having moderate reaction conditions.

[0045] Example 4

[0046] (1) Under nitrogen atmosphere, 8.5 g of 1H-imidazole-4-carboxylic acid, 7.31 g of p-fluorobenzaldehyde and 83 mL of N,N-dimethylformamide were added to a reaction flask, stirred evenly, and then 17 g of potassium carbonate was added. The mixture was reacted at 80° C. for 15 h, cooled, extracted with ethyl acetate and deionized water, and the organic phase was concentrated. After separation by column chromatography, 1-benzaldehyde-imidazole carboxylic acid intermediate was obtained.

[0047] (2) Under nitrogen atmosphere, 6 g of diethylenetriamine and 75 mL of methanol were added to a reaction flask, and after stirring, 24.6 g of 1-benzaldehyde-imidazole carboxylic acid intermediate was added, and the mixture was reacted at 70° C. for 4 h, cooled and filtered, washed with methanol, and concentrated under reduced pressure to obtain a bis-imidazole aminocarboxylic acid Schiff base.

[0048] (3) Under nitrogen atmosphere, 3.5 g of a Schiff base of a diimidazole aminocarboxylic acid and 77 mL of acetonitrile were added to a reaction flask. After stirring, 1.68 g of bromoacetic acid and 2.38 g of potassium carbonate were added. The mixture was reacted at 65° C. for 3 h, concentrated under reduced pressure, and dried to obtain an organic acid ligand.

[0049] (4) Add 97 g of bismuth nitrate pentahydrate and 1940 mL of deionized water into a reaction flask, stir evenly, add 135.8 g of an organic acid ligand, place in an ultrasonic cleaner, react at a power of 20 kW and a temperature of 40° C. for 2 h, filter, and dry to obtain a bismuth organic acid having moderate reaction conditions.

[0050] Example 5

[0051] (1) Under nitrogen atmosphere, 22 g of 1H-imidazole-4-carboxylic acid, 18.7 g of p-fluorobenzaldehyde and 240 mL of N,N-dimethylformamide were added to a reaction flask, and after stirring, 34.1 g of potassium carbonate was added, and the mixture was reacted at 90° C. for 12 h. The mixture was cooled, extracted with ethyl acetate and deionized water, and the organic phase was concentrated. After separation by column chromatography, a 1-benzaldehyde-imidazole carboxylic acid intermediate was obtained.

[0052] (2) Under a nitrogen atmosphere, 14 g of diethylenetriamine and 182 mL of methanol were added to a reaction flask, and after stirring, 54.6 g of 1-benzaldehyde-imidazole carboxylic acid intermediate was added, and the mixture was reacted at 65° C. for 5 h, cooled and filtered, washed with methanol, and concentrated under reduced pressure to obtain a bis-imidazolylaminocarboxylic acid Schiff base.

[0053] (3) Under nitrogen atmosphere, 8 g of bisimidazolylaminocarboxylic acid Schiff base and 145 mL of acetonitrile were added to a reaction flask, stirred evenly, and then 4.16 g of bromoacetic acid and 5.2 g of potassium carbonate were added. The mixture was reacted at 60° C. for 2 h, concentrated under reduced pressure, and dried to obtain an organic acid ligand.

[0054] (4) Add 38.8 g of bismuth nitrate pentahydrate and 970 mL of deionized water to a reaction flask, stir evenly, add 62.08 g of an organic acid ligand, place in an ultrasonic cleaner, react at a power of 20 kW and a temperature of 40° C. for 4 h, filter, and dry to obtain a bismuth organic acid having moderate reaction conditions.

[0055] Table 1 Organic acid bismuth yield and purity test

[0056]

[0057] It can be seen from the test results in the above table that with the increase in the amount of organic acid ligand, under the premise that other conditions remain consistent, the yield of organic acid bismuth gradually increases, and the yield in Example 4 reaches 98.1%, and the purity is 98.5%. This is because the synthesized organic acid ligand structure has a variety of coordination atoms with coordination capabilities, including O atoms on the polycarboxylic acid group and N atoms on the imidazole and two N atoms provided by two Schiff bases, and the benzene ring and the imidazole ring are connected by a CN single bond, and the two can rotate arbitrarily, so that the organic acid ligand can be suitable for the coordination of various structures, thereby obtaining a stable structure, thereby improving the utilization rate of the bismuth source, and being suitable for mass production.

[0058] Example 6

[0059] The difference between this embodiment and embodiment 4 is that the power in step (4) is 30 kW, and other conditions remain the same.

[0060] Example 7

[0061] The difference between this embodiment and embodiment 4 is that the power in step (4) is 40 kW, and other conditions remain the same.

[0062] Example 8

[0063] The difference between this embodiment and embodiment 4 is that the temperature in step (4) is 50° C., and other conditions remain the same.

[0064] Example 9

[0065] The difference between this embodiment and embodiment 4 is that the temperature in step (4) is 60° C., and other conditions remain the same.

[0066] Comparative Example 1

[0067] The difference between this comparative example and Example 4 is that 1-benzaldehyde-imidazole carboxylic acid intermediate is used to replace the organic acid ligand, and other conditions remain the same.

[0068] Add 97 g of bismuth nitrate pentahydrate and 25 mL of deionized water to a reaction flask, stir evenly, then add 135.8 g of 1-benzaldehyde-imidazole carboxylic acid intermediate, place in an ultrasonic cleaner, react at a power of 20 kW and a temperature of 40°C for 2 h, filter, and dry to obtain organic acid bismuth.

[0069] Comparative Example 2

[0070] The difference between this comparative example and Example 4 is that the organic acid ligand is replaced by a bisimidazolylaminocarboxylic acid Schiff base, and other conditions remain the same.

[0071] Add 97 g of bismuth nitrate pentahydrate and 25 mL of deionized water into a reaction flask, stir evenly, then add 135.8 g of diimidazole aminocarboxylic acid Schiff base, place in an ultrasonic cleaner, react at a power of 20 kW and a temperature of 40° C. for 2 h, filter, and dry to obtain organic acid bismuth.

[0072] Table 2 Effect of power and temperature on yield

[0073]

[0074]

[0075] It can be seen from the test results in the above table that the greater the ultrasonic power and the higher the reaction temperature, the more energy is provided for the synthesis of organic acid bismuth. The ultrasonic method can quickly heat up and provide continuous impact force, thereby significantly improving the yield of organic acid bismuth.

[0076] Comparative Example 1 contains only one carboxylic acid and one imidazole group, and the coordination effect with bismuth is limited, so the yield of the obtained organic acid bismuth is low; Comparative Example 2 contains two carboxylic acids, two Schiff bases and two imidazole groups, but the coordination effect with bismuth is poor and the yield is low; therefore, the organic acid ligand prepared by the present invention can produce a stable coordination effect with bismuth, has many coordination sites, mild reaction conditions, low production cost, short production cycle, and is suitable for large-scale production.

[0077] The above contents are merely examples and explanations of the structure of the present invention. The technicians in this technical field may make various modifications or additions to the specific embodiments described or replace them in a similar manner. As long as they do not deviate from the structure of the invention or exceed the scope defined by the claims, they should all fall within the protection scope of the present invention.

Claims

1. A method for preparing bismuth organic acid under moderate reaction conditions, characterized in that: The preparation method comprises the following steps: (1) In a nitrogen atmosphere, a Schiff base of bisimidazolylaminocarboxylic acid and acetonitrile are added to a reaction flask, and after stirring evenly, bromoacetic acid and potassium carbonate are added, and the mixture is stirred for reaction. After the reaction is completed, the mixture is concentrated under reduced pressure and dried to obtain an organic acid ligand having the structural formula: (2) adding bismuth nitrate pentahydrate and deionized water to a reaction flask, stirring evenly, adding an organic acid ligand, placing the flask in an ultrasonic cleaner, stirring the reaction at a power of 20-40 kW, filtering, and drying to obtain a bismuth organic acid with moderate reaction conditions; The structural formula of the bisimidazolylaminocarboxylic acid Schiff base is:

2. The method for preparing a bismuth organic acid under reaction conditions as claimed in claim 1, wherein: In the step (1), the ratio of the Schiff base of the bisimidazolylaminocarboxylic acid, acetonitrile, bromoacetic acid and potassium carbonate is 1 g: (15-25) mL: (0.45-0.55) g: (0.6-0.8) g.

3. The method for preparing bismuth organic acid under the reaction conditions of claim 1, characterized in that: In the step (1), the reaction temperature is 55-70° C. and the reaction time is 1-3 h.

4. The method for preparing bismuth organic acid under the reaction conditions of claim 1, wherein: In the step (2), the ratio of bismuth nitrate pentahydrate, deionized water, and organic acid ligand is 1 g: (20-30) mL: (1.1-1.6) g.

5. The method for preparing bismuth organic acid under the reaction conditions of claim 1, characterized in that: In the step (2), the reaction temperature is 40-60° C. and the reaction time is 2-4 h.

6. The method for preparing organic bismuth acid under the reaction conditions of claim 1, characterized in that: The method for preparing the Schiff base of bisimidazolylaminocarboxylic acid in step (1) comprises the following steps: S1. Under a nitrogen atmosphere, 1H-imidazole-4-carboxylic acid, p-fluorobenzaldehyde and N,N-dimethylformamide were added to a reaction flask, stirred evenly, and potassium carbonate was added. After the reaction was completed, the mixture was cooled, extracted with ethyl acetate and deionized water, and the organic phase was concentrated. After separation by column chromatography, the obtained 1-benzaldehyde-imidazole carboxylic acid intermediate had the structural formula: S2. Under a nitrogen atmosphere, add diethylenetriamine and methanol to a reaction flask, stir evenly, then add 1-benzaldehyde-imidazolecarboxylic acid intermediate, stir to react, and after the reaction is completed, cool and filter, wash with methanol, and concentrate under reduced pressure to obtain a bis-imidazole aminocarboxylic acid Schiff base.

7. The method for preparing organic bismuth acid under the reaction conditions of claim 6, wherein: In the step S1, the ratio of 1H-imidazole-4-carboxylic acid, p-fluorobenzaldehyde, N,N-dimethylformamide and potassium carbonate is 1 g: (0.8-0.95) g: (8-12) mL: (1.25-2.05) g.

8. The method for preparing organic bismuth acid under the reaction conditions of claim 6, characterized in that: In step S1, the reaction temperature is 75-90° C. and the reaction time is 8-16 hours.

9. The method for preparing organic bismuth acid under the reaction conditions of claim 6, characterized in that: In the step S2, the ratio of diethylenetriamine, methanol, and 1-benzaldehyde-imidazolecarboxylic acid intermediate is 1 g: (10-15) mL: (3.8-4.2) g.

10. The method for preparing organic bismuth acid under moderate reaction conditions according to claim 6, characterized in that: In step S2, the reaction temperature is 60-75° C. and the reaction time is 2-5 h.

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