Preparation method and application of N-phenyl anthranilic acid rare earth complex

Abstract

The invention discloses a preparation method and application of an N-phenyl o-aminobenzoic acid rare earth complex, and the preparation method comprises the following steps: optimizing a mixing reaction process, and adopting an accurate dropwise adding device and a constant stirring speed to ensure that a rare earth nitrate solution and an N-phenyl o-aminobenzoic acid ligand solution are uniformly mixed, so as to obtain the N-phenyl o-aminobenzoic acid rare earth complex. The phenomenon of non-uniform mixing caused by direct addition or simple stirring in the prior art is avoided, so that the problems of supersaturation and incomplete reaction of the solution in a local area are avoided; due to the improvement, rare earth ions and ligands uniformly react in the whole solution, the formation of large particles or non-uniform precipitates is remarkably reduced, meanwhile, the uniform and sufficient reaction of all areas is ensured, and the N-phenyl anthranilic acid rare earth complex is finally obtained. In addition, the invention also discloses a new application of the N-phenyl anthranilic acid rare earth complex, and the N-phenyl anthranilic acid rare earth complex can be added into natural rubber as an anti-aging agent of the natural rubber to improve the thermo-oxidative aging resistance of the natural rubber.

Description

Technical Field

[0001] The present invention belongs to the field of rare earth complexes of N-phenylanthranilic acid, and specifically relates to a preparation method and use of rare earth complexes of N-phenylanthranilic acid. Background Art

[0002] Rare earth complexes of N-phenylanthranilic acid are an important class of organometallic complexes with broad application prospects, especially playing important roles in fields such as catalysts, fluorescent materials, and magnetic materials. These complexes have attracted much attention due to their unique chemical properties and functionality, and occupy an important position in scientific research and industrial applications. In the preparation process, the mixing reaction of rare earth nitrate solution and N-phenylanthranilic acid ligand solution is one of the key steps. Existing technologies usually carry out the mixing reaction by direct addition or simple stirring. However, this method lacks precise control and is prone to uneven mixing. Since supersaturation may occur in local areas of the solution, rare earth ions and ligands react rapidly in these areas, forming large particles or uneven precipitates. At the same time, the reaction in other areas may not be complete, resulting in the presence of remaining unreacted ligands or rare earth ions in the solution. Currently, there is no application of rare earth complexes of N-phenylanthranilic acid as rubber antioxidants.

[0003] In view of this, the present invention is specifically proposed. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to overcome the deficiencies of the prior art and provide a preparation method of rare earth complexes of N-phenylanthranilic acid and a new use as a rubber antioxidant, solving the problems raised in the above background art.

[0005] To solve the above technical problems, the basic concept of the technical solution adopted by the present invention is: A preparation method of rare earth complexes of N-phenylanthranilic acid, comprising the following steps: Step (1): Stir N-phenylanthranilic acid with absolute ethanol at room temperature until completely dissolved to obtain Solution ①.

[0006] Step (2): Adjust the pH value of Solution ① to 7 - 8 using an alkaline solution to obtain Solution ②; adjusting the pH value to 7 - 8 using an alkaline solution (such as sodium hydroxide solution, potassium hydroxide solution, or ammonia water solution) provides the optimal reaction environment to ensure that the reactants can fully react. If the pH value is less than 7, the reaction process will remain acidic, the ligand reaction will be incomplete, and the antioxidant performance of the complex in rubber will decline. If the pH value is greater than 8, the reaction process will be too alkaline, resulting in rare earth hydroxide and the rare earth cannot fully form a complex.

[0007] Step (3): Dissolve rare earth nitrate in deionized water to obtain a rare earth nitrate solution with a solution concentration of 0.1 - 0.5 mol / L. Dissolving rare earth nitrate in deionized water can ensure that the solution contains evenly distributed rare earth elements and there will be no interference from other impurity ions.

[0008] Step (4): Place the reaction solution obtained in step (2) in a constant temperature water bath and heat it to 40 - 70 °C. This step can provide a stable reaction temperature. If the temperature is lower than 40 °C, the reaction will not be complete. If the temperature is higher than 70 °C, the ethanol will volatilize too quickly, affecting the stability of the system concentration.

[0009] Step (5): Dropwise add the rare earth nitrate solution to solution ② obtained in step (4) at a constant rate, and maintain the stirring rate of the solution at 100 - 300 rpm / min during the dropping process to obtain a uniformly mixed reaction solution. After the rare earth nitrate solution is completely dropped, continue to stir at 40 - 70 °C for 1 - 4 hours. Using a titration device to slowly dropwise add the rare earth nitrate solution and controlling the dropping rate can avoid local supersaturation and uneven reaction caused by rapid addition, and the reaction temperature is stable.

[0010] Step (6): Cool the reaction solution obtained in step (5) to room temperature and then perform vacuum filtration, and wash the filter residue alternately with deionized water and absolute ethanol to remove residual impurities; ensure the purity of the product.

[0011] Step (7): Dry the washed filter residue at 60 - 100 °C and continue for 12 - 24 hours under vacuum conditions to obtain a rare earth complex of N-phenylanthranilic acid. Vacuum drying can effectively remove moisture and solvent residues, avoid oxidation, and improve the purity of the product.

[0012] Optionally, the mass ratio of the absolute ethanol used in step (1) to the mass of N-phenylanthranilic acid is 10:1 - 20:1.

[0013] Optionally, the basic solution in step (2) is one of sodium hydroxide solution, potassium hydroxide solution or ammonia water solution.

[0014] Optionally, the rare earth nitrate in step (3) includes but is not limited to one or more combinations of lanthanum nitrate, cerium nitrate, samarium nitrate or yttrium nitrate Optionally, the dropping efficiency of the titration device in step (5) is set to drop 1% - 2% of the rare earth nitrate solution per minute.

[0015] Optionally, the rare earth element is one or more combinations of lanthanum, cerium, samarium or yttrium.

[0016] Optionally, the molar ratio of the rare earth element to N-phenylanthranilic acid is 1:2.5 - 3.

[0017] A rare earth complex of N-phenylanthranilic acid, characterized in that the complex is prepared by the above-mentioned preparation method.

[0018] Use of the above-mentioned rare earth complex of N-phenylanthranilic acid as an antioxidant in rubber materials.

[0019] After adopting the above technical solution, the present invention has the following beneficial effects compared with the prior art. Of course, any product implementing the present invention does not necessarily need to achieve all the advantages described below at the same time: By optimizing the mixing reaction process, using a precise dropping device and a constant stirring rate, this application ensures the uniform mixing of the rare earth nitrate solution and the N-phenylanthranilic acid ligand solution, avoiding the uneven mixing phenomenon caused by direct addition or simple stirring in the prior art, thus avoiding the problems of supersaturation in local areas and incomplete reaction of the solution; this improvement enables the rare earth ions and the ligand to react uniformly throughout the solution, significantly reducing the formation of large particles or uneven precipitates, and at the same time ensuring uniform and sufficient reaction in all areas, and finally obtaining the rare earth complex of N-phenylanthranilic acid. In addition, the present invention also discovers a new use of the rare earth complex of N-phenylanthranilic acid, which can be added to natural rubber as an antioxidant to improve its resistance to thermal oxygen aging.

[0020] The following further describes in detail the specific embodiments of the present invention with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The following drawings in the description are only some embodiments. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts. In the drawings: Figure 1 It is the electron micrograph of Example 1.

[0022] Figure 2 It is the electron micrograph of Example 2.

[0023] It should be noted that these drawings and the text description are not intended to limit the scope of the concept of the present invention in any way, but to illustrate the concept of the present invention to those skilled in the art by referring to specific embodiments. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0024] The present invention will now be further described in detail with reference to the accompanying drawings.

[0025] Please refer to Figure 1-2 As shown, in this embodiment, a preparation method and use of a rare earth complex of N-phenylanthranilic acid are provided, including the following steps: Example 1: A method for preparing a rare earth complex of N-phenylanthranilic acid is provided, comprising the following steps: Step (1): Weigh 53.25 g (0.25 mol) of N-phenylanthranilic acid, add it to 532.5 mL of absolute ethanol, and stir at room temperature until completely dissolved to obtain Solution ①. Step (2): Adjust the pH value of Solution ① to 7.5 using a sodium hydroxide solution to obtain Solution ②. Step (3): Dissolve 43.3 g (0.1 mol) of lanthanum nitrate in 1 L of deionized water to obtain a lanthanum nitrate solution with a solution concentration of 0.1 mol / L; the molar ratio of lanthanum to N-phenylanthranilic acid is 1:2.5.

[0026] Step (4): Place the reaction solution obtained in Step (2) in a constant temperature water bath and heat it to 50 °C. Step (5): Dropwise add the lanthanum nitrate solution to Solution ② obtained in Step (4) at a constant rate. Set the dropping efficiency of the dropping device to 1% of the lanthanum nitrate solution per minute, and maintain the stirring rate of the solution at 100 rpm / min during the dropping process to obtain a uniformly mixed reaction solution; after the addition of the lanthanum nitrate solution is completed, continue to stir at 50 °C for 1 hour.

[0027] Step (6): Cool the reaction solution obtained in Step (5) to room temperature and then perform vacuum filtration. Wash the filter residue alternately with deionized water and absolute ethanol to remove residual impurities. Step (7): Dry the washed filter residue at 60 °C and continue for 12 hours under vacuum conditions to obtain a lanthanum complex of N-phenylanthranilic acid.

[0028] Example 2: A method for preparing a rare earth complex of N-phenylanthranilic acid is provided, comprising the following steps: Step (1): Weigh 63.9 g (0.3 mol) of N-phenylanthranilic acid, add it to 958.5 mL of absolute ethanol, and stir at room temperature until completely dissolved to obtain Solution ①. Step (2): Adjust the pH value of Solution ① to 7 using a sodium hydroxide solution to obtain Solution ②. Step (3): Dissolve 43.4 g (0.1 mol) of cerium nitrate in 0.2 L of deionized water to obtain a cerium nitrate solution with a solution concentration of 0.5 mol / L; the molar ratio of cerium to N-phenylanthranilic acid is 1:3.

[0029] Step (4): Place the reaction solution obtained in Step (2) in a constant temperature water bath and heat it to 60 °C. Step (5): Dropwise add the cerium nitrate solution at a constant rate into solution ② obtained in step (4). Set the dropping efficiency of the dropping device to add 2% cerium nitrate solution per minute. During the dropping process, keep the stirring rate of the solution at 300 rpm / min to obtain a uniformly mixed reaction solution. After the cerium nitrate solution is completely added, continuously stir at 60 °C for 4 hours.

[0030] Step (6): Cool the reaction solution obtained in step (5) to room temperature and then perform vacuum filtration. Wash the filter residue alternately with deionized water and absolute ethanol to remove residual impurities. Step (7): Dry the washed filter residue at 100 °C and keep it under vacuum conditions for 24 hours to obtain cerium N-phenylanthranilate complex.

[0031] Example 3: A method for preparing a rare earth complex of N-phenylanthranilic acid is provided, including the following steps: Step (1): Weigh 59.64 g (0.28 mol) of N-phenylanthranilic acid and add it to 1192.8 mL of absolute ethanol. Stir at room temperature until completely dissolved to obtain solution ①. Step (2): Adjust the pH value of solution ① to 7.5 using an ammonia water solution to obtain solution ②. Step (3): Dissolve 44.4 g (0.1 mol) of samarium nitrate in 0.4 L of deionized water to obtain a samarium nitrate solution with a solution concentration of 0.25 mol / L. The molar ratio of samarium to N-phenylanthranilic acid is 1:2.8.

[0032] Step (4): Place the reaction solution obtained in step (2) in a constant temperature water bath and heat it to 40 °C. Step (5): Dropwise add the samarium nitrate solution at a constant rate into solution ② obtained in step (4). Set the dropping efficiency of the dropping device to add 1.3% samarium nitrate solution per minute. During the dropping process, keep the stirring rate of the solution at 200 rpm / min to obtain a uniformly mixed reaction solution. After the samarium nitrate solution is completely added, continuously stir at 40 °C for 2 hours.

[0033] Step (6): Cool the reaction solution obtained in step (5) to room temperature and then perform vacuum filtration. Wash the filter residue alternately with deionized water and absolute ethanol to remove residual impurities. Step (7): Dry the washed filter residue at 100 °C and keep it under vacuum conditions for 24 hours to obtain samarium N-phenylanthranilate complex.

[0034] Example 4: A method for preparing a rare earth complex of N-phenylanthranilic acid is provided, including the following steps: Step (1): Weigh 53.25 g (0.25 mol) of N-phenylanthranilic acid and add it to 532.5 mL of absolute ethanol. Stir at room temperature until completely dissolved to obtain Solution ①. Step (2): Adjust the pH value of Solution ① to 7 using a potassium hydroxide solution to obtain Solution ②. Step (3): Dissolve 38.3 g (0.1 mol) of yttrium nitrate in 0.2 L of deionized water to obtain a yttrium nitrate solution with a solution concentration of 0.5 mol / L. The molar ratio of yttrium to N-phenylanthranilic acid is 1:2.5.

[0035] Step (4): Place the reaction solution obtained in Step (2) in a constant temperature water bath and heat it to 70 °C. Step (5): Dropwise add the yttrium nitrate solution to Solution ② obtained in Step (4) at a constant rate. Set the dropping efficiency of the dropping device to drop 1.6% of the yttrium nitrate solution per minute. During the dropping process, keep the stirring rate of the solution at 300 rpm / min to obtain a uniformly mixed reaction solution. After the yttrium nitrate solution is completely dropped, continuously stir at 70 °C for 3 hours.

[0036] Step (6): Cool the reaction solution obtained in Step (5) to room temperature and then perform vacuum filtration. Wash the filter residue alternately with deionized water and absolute ethanol to remove residual impurities. Step (7): Dry the washed filter residue at 90 °C and continue for 18 hours under vacuum conditions to obtain a yttrium N-phenylanthranilate complex.

[0037] Comparative Example 1: A method for preparing a rare earth complex of N-phenylanthranilic acid is provided, including the following steps: The difference between Comparative Example 1 and Example 1 is that the pH value adjusted in Step (2) is 6.5, and the remaining steps are the same as those in Example 1.

[0038] Comparative Example 2: A method for preparing a rare earth complex of N-phenylanthranilic acid is provided, including the following steps: The difference between Comparative Example 2 and Example 1 is that the pH value adjusted in Step (2) is 8.5, and the remaining steps are the same as those in Example 1.

[0039] Comparative Example 3: A method for preparing a rare earth complex of N-phenylanthranilic acid is provided, including the following steps: The difference between Comparative Example 3 and Example 2 is that the reaction temperature is controlled at 35 °C, and the remaining steps are the same as those in Example 2.

[0040] Comparative Example 4: A method for preparing a rare earth complex of N-phenylanthranilic acid is provided, including the following steps: The difference between Comparative Example 4 and Example 2 is that the reaction temperature is controlled to 75° C., and the remaining steps are the same as those of Example 2.

[0041] Comparative Example 5: A method for preparing a rare earth complex of N-phenyl anthranilic acid is provided, comprising the following steps: The difference between Comparative Example 5 and Example 3 is that no titration device is used, the rare earth nitrate solution is added quickly and all at once, and the dripping rate is not controlled. The remaining steps are the same as those of Example 2.

[0042] The N-phenyl anthranilic acid rare earth complexes prepared in Examples 1-4 and Comparative Examples 1-5 are used as antioxidants in natural rubber. The rubber formula is as follows: 100 parts by weight of natural rubber, 30 parts by weight of carbon black (N660), 2 parts by weight of N-phenylanthranilic acid rare earth complex, 2 parts by weight of sulfur, 2 parts by weight of stearic acid, 5 parts by weight of zinc oxide and 1.5 parts by weight of accelerator CZ.

[0043] The above natural rubber formula is mixed and vulcanized at 150°C to form a vulcanized rubber, and then the vulcanized rubber is subjected to an aging performance test.

[0044] (1) Mechanical properties: The tensile properties and elongation at break were tested using an electronic universal testing machine in accordance with national standards GB / T528-2009 and GB / T 528-2009 (dumbbell-shaped specimen tensile rate 500 mm / min); (2) Hot air aging performance: The hot air aging test chamber is used to test the thermal oxygen aging performance of the sample in accordance with GB / T 3512-2014. The aging condition is 100℃ for 48 hours.

[0045] The aging properties of the natural rubber vulcanizates prepared in various examples are shown in Table 1.

[0046] Tensile strength Mpa (initial) Tensile strength Mpa (after aging) Rate of change % (decrease) Elongation at break % (initial) Elongation at break % (after aging) Rate of change % (decrease) Example 1 26.7 20.3 24.0% 513 420 18.1% Example 2 26.7 20.8 22.1% 507 421 17.0% Example 3 26.8 19.5 27.2% 517 412 20.3% Example 4 26.7 19.9 25.5% 530 420 20.8% Comparative Example 1 26.6 16.5 38.0% 520 331 36.3% Comparative Example 2 26.3 17.2 34.6% 517 310 40.0% Comparative Example 3 26.8 15.4 42.5% 527 320 39.3% Comparative Example 4 26.9 16.7 37.9% 513 325 36.6% Comparative Example 5 26.7 13.2 50.6% 514 312 39.3% Comparing Examples 1-4 with Comparative Examples 1-5, it can be seen that the vulcanized rubber prepared with the rare earth complex obtained in Examples 1-4 has a smaller decrease in tensile strength and elongation at break after aging at 100° C. for 48 hours, and has better aging resistance.

[0047] The present invention is not limited to the above-mentioned embodiments. Anyone should be aware that any structural changes made under the enlightenment of the present invention, and any technical solutions that are the same or similar to the present invention, fall within the protection scope of the present invention. The technology, shape, and structural parts not described in detail in the present invention are all well-known technologies.

Claims

1. A method for preparing a rare earth complex of N-phenylanthranilic acid, characterized in that, It includes the following steps: Step (1): Stir N-phenylanthranilic acid with absolute ethanol at room temperature until it is completely dissolved to obtain Solution ①; Step (2): Use an alkaline solution to adjust the pH value of Solution ① to 7-8 to obtain Solution ②; Step (3): Dissolve rare earth nitrate in deionized water to obtain a rare earth nitrate solution with a solution concentration of 0.1-0.5 mol / L; Step (4): Place the reaction solution obtained in Step (2) in a constant temperature water bath and heat it to 40-70 °C; Step (5): Dropwise add the rare earth nitrate solution to Solution ② obtained in Step (4) at a constant rate, and maintain the stirring rate of the solution at 100-300 rpm / min during the dropping process to obtain a uniformly mixed reaction solution; After the dropwise addition of the rare earth nitrate solution, continuously stir at 40-70 °C for 1-4 hours; Step (6): Cool the reaction solution obtained in Step (5) to room temperature and then perform vacuum filtration, and alternately wash the filter residue with deionized water and absolute ethanol to remove residual impurities; Step (7): Dry the washed filter residue at 60-100 °C and continue for 12-24 hours under vacuum conditions to obtain a rare earth complex of N-phenylanthranilic acid.

2. The preparation method of a rare earth complex of N-phenylanthranilic acid according to claim 1, characterized in that, The mass ratio of the absolute ethanol used in Step (1) to the mass of N-phenylanthranilic acid is 10:1-20:

1.

3. The preparation method of a rare earth complex of N-phenylanthranilic acid according to claim 1, wherein, The alkaline solution in Step (2) is one of sodium hydroxide solution, potassium hydroxide solution or ammonia water solution.

4. The preparation method of a rare earth complex of N-phenylanthranilic acid according to claim 1, wherein, The rare earth nitrate in Step (3) includes, but is not limited to, one or more combinations of lanthanum nitrate, cerium nitrate, samarium nitrate or yttrium nitrate.

5. The preparation method of a rare earth complex of N-phenylanthranilic acid according to claim 1, characterized in that, In Step (5), the dropping efficiency of the dropping device is set to drop 1%-2% of the rare earth nitrate solution per minute.

6. According to the method for preparing a rare earth complex of N-phenylanthranilic acid described in Claim 1, the rare earth element is one or more combinations of lanthanum, cerium, samarium or yttrium.

7. The preparation method of a rare earth complex of N-phenylanthranilic acid according to claim 1, characterized in that, The molar ratio of the rare earth element to N-phenylanthranilic acid is 1:2.5-3.

8. A rare earth complex of N-phenylanthranilic acid, characterized in that, This complex is prepared by the preparation method described in any one of Claims 1 to 7 above.

9. Use of the rare earth complex of N-phenylanthranilic acid described in Claim 8 as an antioxidant in rubber materials.

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