A method for synthesizing an ultraviolet absorber

Abstract

The application discloses a method for synthesizing ultraviolet absorber in the technical field of ultraviolet absorber, and the method comprises the following steps: taking 50g of SAPO-5 zeolite molecular sieve, and activating the SAPO-5 zeolite molecular sieve with 1000ml of sulfuric acid with a concentration of 0.001M, 1000ml of glacial acetic acid and 1000ml of propionic acid respectively at room temperature for 30min; washing and drying: after the activation is completed, the SAPO-5 zeolite molecular sieve catalyst is obtained by centrifugal washing with deionized water and drying at 80 DEG C for 12h; N-methylaniline, trimethyl orthoformate, ethyl p-aminobenzoate and the catalyst obtained in step S2 are weighed and mixed according to a proportion to obtain a mixed solution; the mixed solution obtained in step S3 is placed in a three-necked flask, the oil temperature of an oil bath is increased to 120-140 DEG C, and the mixed solution is reacted for 2-4h, the generated methanol is separated out during the reaction, then the mixed solution is subjected to vacuum distillation for 2h, and the N-(ethoxycarbonylphenyl)-N'-methyl-N'-phenylformamidine product is obtained by filtration, in the application, the product has high selectivity and high conversion rate in the synthesis, and the zeolite catalyst can also adsorb the pigment of the product, so that the color value of the product is reduced.

Description

Technical Field

[0001] This invention relates to a preparation technique with high selectivity and high conversion rate for the one-pot synthesis of the ultraviolet absorber N-(ethoxycarbonylphenyl)-N'-methyl-N'-phenylformamidine using SAPO-5 zeolite molecular sieves etched with protic acid as a catalyst, and particularly to a method for synthesizing ultraviolet absorbers. Background Technology

[0002] AFI molecular sieves possess a one-dimensional 12MR channel growing parallel to the C-axis, belong to the hexagonal crystal system, and also exhibit a large pore size (7.3 Å) and a hexagonal prism framework structure. They demonstrate outstanding performance and advantages in the field of catalysis, especially in catalytic reactions involving macromolecules, and have gradually become a research hotspot in recent years. Their unique topological structure also makes them promising candidates for shape-selective catalysis.

[0003] N-(ethoxycarbonylphenyl)-N'-methyl-N'-phenylformamidinium, an ultraviolet absorber, is a type of additive that strongly absorbs ultraviolet light with wavelengths from 290nm to 400nm. It can absorb the ultraviolet portion of sunlight and fluorescent light sources without changing itself, and can effectively prevent ultraviolet light from damaging polymers (including plastics, rubber, fiber coatings, etc.).

[0004] Commonly used UV absorbers for polymers include benzotriazoles, benzophenones, triazines, and formamides. Formamide UV absorber N-(ethoxycarbonylphenyl)-N'-methyl-N'-phenylformamidinium strongly absorbs light in the 290nm~340nm wavelength range, which is the sensitive wavelength range for most polymers, thus providing good protection for most polymers. Compared to benzotriazole UV absorbers, which have the best absorption effect, formamide UV absorber UV-1 has a similar absorption intensity in the 290nm~340nm wavelength range, but its price is only half to one-third of that of benzotriazoles, offering excellent cost-effectiveness. UV-1, a methyl ether UV absorber, is liquid and ideal for addition to liquid resin materials, widely used in polyurethane (foamed sponges, elastomers, leather, shoe materials), epoxy resins, unsaturated polyester resins, paints, coatings, adhesives, potting compounds, and crystal epoxy resins.

[0005] Currently, the common method for preparing N-(ethoxycarbonylphenyl)-N'-methyl-N'-phenylformamidinium is a two-step synthesis. Although it can successfully synthesize ultraviolet absorbers, it has many drawbacks, such as: the transfer of materials after the first step of synthesis causes the loss of intermediates and reduces the product yield; the intermediates synthesized in the first step are unstable; and the product needs to be prepared on demand, making the operation in production quite cumbersome. Summary of the Invention

[0006] The purpose of this section is to outline some aspects of embodiments of the present invention and to briefly describe some preferred embodiments. Simplifications or omissions may be made in this section, as well as in the abstract and title of the invention, to avoid obscuring the purpose of these documents; however, such simplifications or omissions should not be construed as limiting the scope of the invention.

[0007] Therefore, the purpose of this invention is to provide a method for synthesizing ultraviolet absorbers, which solves the problems of intermediate loss, reduced product yield, instability of intermediates synthesized in the first step, and the need for on-the-spot preparation of the synthesized product in the prior art, which are cumbersome in production. This invention provides a method for synthesizing ultraviolet absorbers, adopting the following technical solution: The method for synthesizing ultraviolet absorbers includes the following specific steps:

[0008] Step S1: Activation: Weigh 50 g of SAPO-5 zeolite molecular sieve and activate it for 30 min at room temperature with 1000 ml of 0.001 M sulfuric acid, glacial acetic acid and propionic acid respectively.

[0009] Step S2: Washing and drying: After activation, the catalyst is washed by centrifugation with deionized water and dried at 80 °C for 12 h to obtain proton acid etched SAPO-5 zeolite molecular sieve catalyst.

[0010] Step S3: Weighing and mixing: Weigh and mix N-methylaniline, trimethyl orthoformate, ethyl p-aminobenzoate, and the catalyst obtained in step S2 according to the specified proportions to obtain a mixture.

[0011] Step S4: Mixing reaction: Place the mixture obtained in step S3 into a three-necked flask, raise the oil temperature of the oil bath to 120-140℃ and react for 2-4 hours. Methanol is generated during the reaction, and then the mixture is distilled under reduced pressure for 2 hours. The product is N-(ethoxycarbonylphenyl)-N'-methyl-N'-phenylformamidinium is obtained by filtration.

[0012] Optionally, the mass ratio of the mixture in step S3 is: N-methylaniline: trimethyl orthoformate: ethyl p-aminobenzoate: catalyst = 0.8~1.2: 1.3~1.7: 1.3~1.6: m / 100, where m is the mass of ethyl p-aminobenzoate.

[0013] Optionally, in step S4, the order of feeding is N-methylaniline, trimethyl orthoformate, ethyl p-aminobenzoate, and protonic acid-etched SAPO-5 molecular sieve catalyst.

[0014] Optionally, the synthesized ultraviolet absorber has a purity of 99-99.6% and a color ≤2.

[0015] In summary, the present invention has at least one of the following beneficial effects:

[0016] The synthesis of N-(ethoxycarbonylphenyl)-N'-methyl-N'-phenylformamidine can be achieved efficiently and rapidly using protonic acid etching of SAPO-5 zeolite molecular sieve as a catalyst. This method is simple, convenient, and easy to operate, and the catalyst is recyclable, showing great application potential. In this application, the use of protonic acid etching of SAPO-5 zeolite molecular sieve as a catalyst for the synthesis of N-(ethoxycarbonylphenyl)-N'-methyl-N'-phenylformamidine not only demonstrates high selectivity and high conversion rate in the synthesis, but the zeolite catalyst can also adsorb pigments from the product, reducing its color value. Attached Figure Description

[0017] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is the gas chromatogram of the N-(ethoxycarbonylphenyl)-N'-methyl-N'-phenylformamidinine standard of the present invention;

[0019] Figure 2 This is the gas phase data sheet for the N-(ethoxycarbonylphenyl)-N'-methyl-N'-phenylformamidinium standard of the present invention;

[0020] Figure 3 This is the optimal gas phase spectrum of N-(ethoxycarbonylphenyl)-N'-methyl-N'-phenylformamidinium for this invention;

[0021] Figure 4 Table 1 shows the optimal gas phase data for N-(ethoxycarbonylphenyl)-N'-methyl-N'-phenylformamidinium for this invention. Detailed Implementation

[0022] The following is in conjunction with the appendix Figure 1-4 The present invention will be described in further detail below.

[0023] This invention discloses a method for synthesizing ultraviolet absorbers, which solves the problem of monitoring and regulating the gas pressure in the process of synthesizing ultraviolet absorbers, including,

[0024] The specific steps are as follows:

[0025] Step S1: Activation: Weigh 50 g of SAPO-5 zeolite molecular sieve and activate it for 30 min at room temperature with 1000 ml of 0.001 M sulfuric acid, glacial acetic acid and propionic acid respectively.

[0026] Step S2: Washing and drying: After activation, the catalyst is washed by centrifugation with deionized water and dried at 80 °C for 12 h to obtain proton acid etched SAPO-5 zeolite molecular sieve catalyst.

[0027] Step S3: Weighing and mixing: Weigh and mix N-methylaniline, trimethyl orthoformate, ethyl p-aminobenzoate, and the catalyst obtained in step S2 according to the specified proportions to obtain a mixture.

[0028] Step S4: Mixing reaction: Place the mixture obtained in step S3 into a three-necked flask, raise the oil temperature of the oil bath to 120-140℃ and react for 2-4 hours. Methanol is generated during the reaction, and then the mixture is distilled under reduced pressure for 2 hours. The product is N-(ethoxycarbonylphenyl)-N'-methyl-N'-phenylformamidinium is obtained by filtration.

[0029] The mass ratio of the mixture in step S3 is: N-methylaniline: trimethyl orthoformate: ethyl p-aminobenzoate: catalyst = 0.8~1.2: 1.3~1.7: 1.3~1.6: m / 100, where m is the mass of ethyl p-aminobenzoate.

[0030] In step S4, the order of feeding is as follows: N-methylaniline, trimethyl orthoformate, ethyl p-aminobenzoate, and protonic acid-etched SAPO-5 molecular sieve catalyst.

[0031] The synthesized ultraviolet absorber has a purity of 99-99.6% and a color ≤2.

[0032] The following embodiments are further illustrations of the present invention, but should not be construed as limiting the scope of the invention.

[0033] Example 1: Synthesis of N-(ethoxycarbonylphenyl)-N'-methyl-N'-phenylformamidin:

[0034] 20g of N-methylaniline and 31.5g of trimethyl orthoformate were placed in a three-necked flask and stirred. 29.6g of ethyl p-aminobenzoate and 0.3g of glacial acetic acid-etched SAPO-5 molecular sieve catalyst were transferred to the flask. The oil bath temperature was raised to 120-140℃ and the reaction was carried out for 2 hours. Methanol was separated during the reaction. Then, the product was subjected to vacuum distillation at 140℃ for 2 hours, and filtered to obtain N-(ethoxycarbonylphenyl)-N'-methyl-N'-phenylformamidinium. The product purity was tested to be 99.566%, and the color was 1.4.

[0035] Example 2: Synthesis of N-(ethoxycarbonylphenyl)-N'-methyl-N'-phenylformamidin:

[0036] 20g of N-methylaniline and 26g of trimethyl orthoformate were placed in a three-necked flask and stirred. 29.6g of ethyl p-aminobenzoate and 0.3g of glacial acetic acid-etched SAPO-5 molecular sieve catalyst were transferred to the flask. The oil bath temperature was raised to 120-140℃ and the reaction was carried out for 2 hours. Methanol was separated during the reaction. Then, the product was subjected to vacuum distillation at 140℃ for 2 hours, and filtered to obtain N-(ethoxycarbonylphenyl)-N'-methyl-N'-phenylformamidinium. The product purity was tested to be 99.06%, and the color was 1.8.

[0037] Example 3: Synthesis of N-(ethoxycarbonylphenyl)-N'-methyl-N'-phenylformamidin:

[0038] 20g of N-methylaniline and 29g of trimethyl orthoformate were placed in a three-necked flask and stirred. 29.6g of ethyl p-aminobenzoate and 0.3g of glacial acetic acid-etched SAPO-5 molecular sieve catalyst were transferred to the flask. The oil bath temperature was raised to 120-140℃ and the reaction was carried out for 2 hours. Methanol was separated during the reaction. Then, the mixture was distilled under reduced pressure at 140℃ for 2 hours, and filtered to obtain N-(ethoxycarbonylphenyl)-N'-methyl-N'-phenylformamidinium. The product purity was tested to be 99.06%, and the color was 1.8.

[0039] Example 4: Synthesis of N-(ethoxycarbonylphenyl)-N'-methyl-N'-phenylformamidinium:

[0040] 20g of N-methylaniline and 34g of trimethyl orthoformate were placed in a three-necked flask and stirred. 29.6g of ethyl p-aminobenzoate and 0.3g of glacial acetic acid were then transferred to the flask to etch the SAPO-5 molecular sieve catalyst. The oil bath temperature was raised to 120-140℃ and the reaction was carried out for 2 hours. Methanol was separated during the reaction. The product was then subjected to vacuum distillation at 140℃ for 2 hours, and filtered to obtain N-(ethoxycarbonylphenyl)-N'-methyl-N'-phenylformamidinium. The product purity was tested to be 99.22%, and the color was 1.6.

[0041] Example 5: Synthesis of N-(ethoxycarbonylphenyl)-N'-methyl-N'-phenylformamidin:

[0042] 20g of N-methylaniline and 31.5g of trimethyl orthoformate were placed in a three-necked flask and stirred. 26g of ethyl p-aminobenzoate and 0.3g of glacial acetic acid-etched SAPO-5 molecular sieve catalyst were transferred to the flask. The oil bath temperature was raised to 120-140℃ and the reaction was carried out for 2 hours. Methanol was separated during the reaction. Then, the product was subjected to vacuum distillation at 140℃ for 2 hours, and filtered to obtain N-(ethoxycarbonylphenyl)-N'-methyl-N'-phenylformamidinium. The purity of the product was tested to be 98.801%, and the color was 2.3.

[0043] Example 6: Synthesis of N-(ethoxycarbonylphenyl)-N'-methyl-N'-phenylformamidinium:

[0044] 20g of N-methylaniline and 31.5g of trimethyl orthoformate were placed in a three-necked flask and stirred. 32g of ethyl p-aminobenzoate and 0.3g of glacial acetic acid-etched SAPO-5 molecular sieve catalyst were transferred to the flask. The oil bath temperature was raised to 120-140℃ and the reaction was carried out for 2 hours. Methanol was separated during the reaction. Then, the product was subjected to vacuum distillation at 140℃ for 2 hours, and filtered to obtain N-(ethoxycarbonylphenyl)-N'-methyl-N'-phenylformamidinium. The purity of the product was tested to be 98.679%, and the color was 1.6.

[0045] Example 7: Synthesis of N-(ethoxycarbonylphenyl)-N'-methyl-N'-phenylformamidinium:

[0046] 16.5g of N-methylaniline and 31.5g of trimethyl orthoformate were placed in a three-necked flask and stirred. 29.6g of ethyl p-aminobenzoate and 0.3g of glacial acetic acid-etched SAPO-5 molecular sieve catalyst were transferred to the flask. The oil bath temperature was raised to 120-140℃ and the reaction was carried out for 2 hours. Methanol was separated during the reaction. Then, the product was subjected to vacuum distillation at 140℃ for 2 hours, and filtered to obtain N-(ethoxycarbonylphenyl)-N'-methyl-N'-phenylformamidinium. The purity of the product was tested to be 98.907%, and the color was 1.5.

[0047] Example 8: Synthesis of N-(ethoxycarbonylphenyl)-N'-methyl-N'-phenylformamidin:

[0048] 24g of N-methylaniline and 31.5g of trimethyl orthoformate were placed in a three-necked flask and stirred. 29.6g of ethyl p-aminobenzoate and 0.3g of glacial acetic acid-etched SAPO-5 molecular sieve catalyst were transferred to the flask. The oil bath temperature was raised to 120-140℃ and the reaction was carried out for 2 hours. Methanol was separated during the reaction. Then, the product was subjected to vacuum distillation at 140℃ for 2 hours, and filtered to obtain N-(ethoxycarbonylphenyl)-N'-methyl-N'-phenylformamidinium. The product purity was tested to be 99.441%, and the color was 1.9.

[0049] Example 9: Synthesis of N-(ethoxycarbonylphenyl)-N'-methyl-N'-phenylformamidin:

[0050] 20g of N-methylaniline and 31.5g of trimethyl orthoformate were placed in a three-necked flask and stirred. 29.6g of ethyl p-aminobenzoate and 0.3g of sulfuric acid-etched SAPO-5 molecular sieve catalyst were transferred to the flask. The oil bath temperature was raised to 120-140℃ and the reaction was carried out for 2 hours. Methanol was separated during the reaction. Then, the product was subjected to vacuum distillation at 140℃ for 2 hours, and filtered to obtain N-(ethoxycarbonylphenyl)-N'-methyl-N'-phenylformamidinium. The purity of the product was tested to be 94.421%, and the color was 2.4.

[0051] Example 10: Synthesis of N-(ethoxycarbonylphenyl)-N'-methyl-N'-phenylformamidinium:

[0052] 20g of N-methylaniline and 31.5g of trimethyl orthoformate were placed in a three-necked flask and stirred. 29.6g of ethyl p-aminobenzoate and 0.3g of propionic acid-etched SAPO-5 molecular sieve catalyst were transferred to the flask. The oil bath temperature was raised to 120-140℃ and the reaction was carried out for 2 hours. Methanol was separated during the reaction. Then, the product was subjected to vacuum distillation at 140℃ for 2 hours, and filtered to obtain N-(ethoxycarbonylphenyl)-N'-methyl-N'-phenylformamidinium. The purity of the product was tested to be 95.965%, and the color was 2.1.

[0053] The above are all preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Therefore, all equivalent changes made in accordance with the structure, shape and principle of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A method for synthesizing an ultraviolet absorber, characterized in that: include, The specific steps are as follows: Step S1: Activation: Weigh 50 g of SAPO-5 zeolite molecular sieve and activate it with 1000 ml of 0.001 M glacial acetic acid at room temperature for 30 min; Step S2: Washing and drying: After activation, the catalyst is washed by centrifugation with deionized water and dried at 80 °C for 12 h to obtain proton acid etched SAPO-5 zeolite molecular sieve catalyst. Step S3: Weighing and mixing: Weigh and mix N-methylaniline, trimethyl orthoformate, ethyl p-aminobenzoate, and the catalyst obtained in step S2 according to the specified proportions to obtain a mixture. Step S4: Mixing reaction: Place the mixture obtained in step S3 into a three-necked flask, raise the oil temperature of the oil bath to 120-140℃ and react for 2-4 hours. Methanol is generated during the reaction, and then the mixture is distilled under reduced pressure for 2 hours. The product is N-(ethoxycarbonylphenyl)-N'-methyl-N'-phenylformamidinium is obtained by filtration.

2. The method for synthesizing ultraviolet absorbers according to claim 1, characterized in that: The mass ratio of the mixture in step S3 is: N-methylaniline: trimethyl orthoformate: ethyl p-aminobenzoate: catalyst = 0.8~1.2: 1.3~1.7: 1.3~1.6: m / 100, where m is the mass of ethyl p-aminobenzoate.

3. The method for synthesizing ultraviolet absorbers according to claim 1, characterized in that: The purity of the ultraviolet absorber synthesized in step S4 is 99-99.6%.

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