Synthesis Method of an Ultraviolet Absorbent UV-3030

Abstract

The present invention discloses a synthesis method of ultraviolet absorber UV-3030. UV-3035 and pentaerythritol are dissolved in N,N-diethylformamide, and after adding a supported mixed rare earth carbonate catalyst, a reflux reaction is carried out. The reaction product is filtered and purified to obtain UV-3030. The synthesis method has the advantages of high product yield, good selectivity, recyclability of the catalyst, etc., greatly reducing the process cost of this product and having significant industrial application prospects.

Description

Technical Field

[0001] The present invention relates to the technical field of the preparation of ultraviolet absorbers, and specifically to a synthesis method of an ultraviolet absorber UV-3030. Background Art

[0002] UV-3030 (pentaerythritol tetra(2-cyano-3,3-diphenylacrylate)) is an ultraviolet absorber with a wide range of uses, and can be used in sunscreen cosmetics, plastics, resins, synthetic rubbers and other polymer material products, especially suitable for transparent products such as polycarbonate, polymethyl methacrylate, polyethylene terephthalate, etc. It has the advantages of high temperature resistance, high extraction resistance, low volatility, low migration, good thermal stability, high absorption efficiency and good compatibility with various polymer materials.

[0003] The current industrial production method of UV-3030 is to use UV-3035 and pentaerythritol under solvent-free conditions, with lithium hydroxide or organotin oxide as a catalyst, and react at 175 °C under vacuum for 10-15 hours, and then extract and recrystallize with toluene to obtain the product. This method has many disadvantages that are difficult to overcome during the operation process: First, the reaction under solvent-free conditions is not conducive to the mass transfer process of large molecular weight intermediates. Due to local overheating, the conversion rate decreases, by-products increase, and the product color is very deep. The refining process requires an additional step of decolorization with acidic clay, which not only makes the operation troublesome but also reduces the refining yield. The current process calculates a relatively low yield based on UV-3035; Second, lithium hydroxide and organotin catalysts are expensive, and the catalysts cannot be recovered under the current process conditions, which greatly increases the post-treatment difficulty and process cost.

[0004] In addition to the current industrial production method, some people use pentaerythritol tetracyanoacetate to react with benzophenone imine to synthesize UV-3030. The advantages of this method are mild reaction conditions and no need for a catalyst. The disadvantages are that the synthesis yields of the two intermediates are low, both not exceeding 50%, resulting in too high product costs. Another disadvantage of this method is that the yield of the final product is also low, only 65%. Summary of the Invention

[0005] To address the drawbacks existing in current industrial production methods, the present invention provides a method for synthesizing ultraviolet absorber UV-3030, which improves the synthesis route of UV-3030: First, diethylformamide (DEF) is used as the reaction medium, which improves the mass and heat transfer states of raw materials and intermediate molecules during the reaction, making the reaction more stable, reducing the generation of by-products, and reducing the phenomenon of the system color deepening caused by overheating; A more efficient supported mixed rare earth carbonate is used as the catalyst, making the reaction more selective, and almost no trisubstituted or disubstituted by-products are generated; In addition, this catalyst can be recovered and reused by simple filtration, reducing the product cost caused by catalyst consumption.

[0006] To achieve the above object, the solution of the present invention is as follows:

[0007] A method for synthesizing ultraviolet absorber UV-3030, comprising the following steps: dissolving UV-3035 and pentaerythritol in diethylformamide, adding a supported mixed rare earth carbonate catalyst, and then carrying out a reflux reaction. The reaction product is filtered and purified to obtain UV-3030.

[0008] There are three aspects to the technical principle of selecting DEF as the reaction medium. First, its boiling point is 178 °C, which is close to the optimal temperature of 175 °C for the transesterification reaction of UV-3035 and pentaerythritol, enabling the transesterification reaction to proceed effectively; Second, DEF is a good solvent, and both reactants, transesterification reaction intermediates, and products have good solubility in it. The formed solution has a small viscosity, can form an effective homogeneous reaction microzone on the catalyst surface, and can quickly diffuse the reaction products out of the reaction microzone, greatly improving the reaction efficiency; Third, the homogeneous reaction system with a small viscosity is more conducive to the heat transfer process, avoiding the overheating phenomenon near the heating surface of the reaction vessel, making the color of the product very light, and being beneficial to the post-treatment refining process.

[0009] Furthermore, the supported mixed rare earth carbonate catalyst is obtained by suspending ZSM-11 molecular sieve in a rare earth halide solution, adding ammonium bicarbonate under stirring, standing to obtain a precipitate, filtering the precipitate, washing it with water, drying it, and then calcining it.

[0010] Rare earth metal salts have good catalytic effects on transesterification reactions as Lewis acids. In the present invention, the carbonate of mixed rare earth metals is loaded on ZSM-11 molecular sieve. On the one hand, by increasing the surface area of rare earth metal carbonate, its catalytic activity is improved; on the other hand, the catalyst has good shape stability and is easy to recycle after the reaction. Experimental results show that the reaction activity of the supported mixed rare earth carbonate catalyst is higher than that of lithium hydroxide and organotin, and the color of the reaction system is better than that of the catalytic systems catalyzed by lithium hydroxide and organotin. It is a catalyst with excellent performance and can be recycled and reused.

[0011] Preferably, the particle size of the ZSM-11 molecular sieve is 0.5 - 2 mm.

[0012] Preferably, the rare earth halide is rare earth chloride, and the rare earth is selected from rare earth elements, preferably light rare earth elements; the mass ratio of the ZSM-11 molecular sieve, rare earth chloride, and ammonium bicarbonate is 10:1:1.5.

[0013] Further, the molar feed ratio of UV-3035 and pentaerythritol is (4 - 6):1.

[0014] Further, the volume of the diethylformamide is 0.5 - 2 times the mass of UV-3035, with the volume unit being mL and the mass unit being g.

[0015] Further, the addition amount of the supported mixed rare earth carbonate catalyst is 0.5 - 2% of the mass of UV-3035.

[0016] Further, the reflux reaction time is 8 - 12 hours.

[0017] Further, the supported mixed rare earth carbonate catalyst is recovered during the filtration process and recycled for catalytic reactions more than 5 times.

[0018] Further, in the purification process, recrystallization is carried out using a mixed solution of tetrachloroethylene and ethyl acetate. The volume ratio of tetrachloroethylene to ethyl acetate is 1:0.5, and the volume of the mixed solution is 2 times the mass of UV-3035. A composite solvent of non-polar tetrachloroethylene and polar ethyl acetate is used to refine crude UV-3030, and UV-3030 with a content of over 99% can be obtained in one treatment, which has a better effect compared to toluene used industrially. The reason for achieving this effect is that tetrachloroethylene has good solubility for the reaction raw material UV3035, while ethyl acetate has good solubility for the trisubstituted and disubstituted by-products. The solubilities of both solvents in UV-3030 are relatively small. Therefore, during the recrystallization process, the excessively fed UV-3035 and the disubstituted and trisubstituted by-products generated during the reaction can be well removed, and a high-purity product can be obtained with a high yield.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] 1. The synthesis method of the present invention uses the solvent method to synthesize UV-3030, which has the advantages of mild reaction conditions, high product yield, and good reaction selectivity in combination with the supported mixed rare earth carbonate catalyst, greatly reducing the process cost of this product.

[0021] 2. The supported catalyst used in the synthesis method of the present invention has high catalytic efficiency and good selectivity. After use, it can be simply recovered and reused, reducing production costs and eliminating the problems of separation and treatment of waste catalysts.

[0022] 3. The purification process in the synthesis method of the present invention is simple. It does not require an acid clay decolorization process. A purity of over 99% can be achieved by a single recrystallization using a mixed solvent of tetrachloroethylene and ethyl acetate. The purification process has low costs and high yields. Specific Embodiments

[0023] The technical solutions of the present invention will be clearly and completely described below in conjunction with preferred embodiments. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of them. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts fall within the scope of protection of the present invention.

[0024] Preparation Examples

[0025] The commercially available ZSM-11 molecular sieve has a particle size range of 0.5 - 2 mm. 50 g of the above ZSM-11 molecular sieve is suspended in 500 mL of a lanthanum chloride solution with a concentration of 10 g / L. While stirring, 500 mL of a 15 g / L ammonium bicarbonate solution is added. The mixture is stirred and reacted for 30 min, then left to stand for precipitation. The resulting precipitate is filtered, washed with water, dried, and calcined at 200 °C for 2 hours to obtain a supported mixed rare earth carbonate catalyst, which is used for the preparation of UV-3030 in the following examples.

[0026] Example 1

[0027] 40 g of UV-3035 and 3.8 g of pentaerythritol (5.2:1, mol / mol) are dissolved in 40 mL of diethylformamide. 0.6 g of the supported mixed rare earth carbonate catalyst is added, and the mixture is heated under reflux for 12 hours. After cooling, the catalyst is recovered by filtration, and the solvent is recovered under reduced pressure to obtain a crude product of the ultraviolet absorber UV-3030. The crude product is dissolved in 80 mL of a mixed solvent of tetrachloroethylene and ethyl acetate (1:0.5, V / V), and left to crystallize in an ice-salt bath for 12 hours. The solvent is removed by filtration, and the solvent is removed by heating to the molten state to obtain 25.2 g of the refined product of UV3030. The content detected by liquid chromatography is 99.6%. The product yield calculated based on UV-3035 is 85.1%.

[0028] Example 2

[0029] 31 g of UV-3035 and 3.8 g of pentaerythritol (4.0:1 mol / mol) were dissolved in 30 mL of diethylformamide. 0.45 g of the supported mixed rare earth carbonate catalyst was added, and the mixture was heated under reflux for 12 hours. After cooling, the catalyst was recovered by filtration, and the solvent was removed by distillation under reduced pressure to obtain the crude product of the ultraviolet absorber UV-3030. The crude product was dissolved in 60 mL of a mixed solvent of tetrachloroethylene and ethyl acetate (1:0.5, V / V), and crystallized in an ice-salt bath for 12 hours. The solvent was removed by filtration, and the solvent was removed by heating to the molten state to obtain 21.2 g of the refined product of UV3030. The content detected by liquid chromatography was 99.5%. The product yield calculated based on UV-3035 was 71.6%.

[0030] Example 3

[0031] 34 g of UV-3035 and 3.8 g of pentaerythritol (4.4:1 mol / mol) were dissolved in 34 mL of diethylformamide. 0.5 g of the supported mixed rare earth carbonate catalyst was added, and the mixture was heated under reflux for 12 hours. After cooling, the catalyst was recovered by filtration, and the solvent was removed by distillation under reduced pressure to obtain the crude product of the ultraviolet absorber UV-3030. The crude product was dissolved in 70 mL of a mixed solvent of tetrachloroethylene and ethyl acetate (1:0.5, V / V), and crystallized in an ice-salt bath for 12 hours. The solvent was removed by filtration, and the solvent was removed by heating to the molten state to obtain 22.6 g of the refined product of UV3030. The content detected by liquid chromatography was 99.7%. The product yield calculated based on UV-3035 was 76.3%.

[0032] Example 4

[0033] 37 g of UV-3035 and 3.8 g of pentaerythritol (4.8:1 mol / mol) were dissolved in 37 mL of diethylformamide. 0.55 g of the supported mixed rare earth carbonate catalyst was added, and the mixture was heated under reflux for 12 hours. After cooling, the catalyst was recovered by filtration, and the solvent was removed by distillation under reduced pressure to obtain the crude product of the ultraviolet absorber UV-3030. The crude product was dissolved in 74 mL of a mixed solvent of tetrachloroethylene and ethyl acetate (1:0.5, V / V), and crystallized in an ice-salt bath for 12 hours. The solvent was removed by filtration, and the solvent was removed by heating to the molten state to obtain 24.1 g of the refined product of UV3030. The content detected by liquid chromatography was 99.2%. The product yield calculated based on UV-3035 was 81.4%.

[0034] Example 5

[0035] 43.3 g of UV-3035 and 3.8 g of pentaerythritol (5.6:1 mol / mol) were dissolved in 44 mL of diethylformamide. 0.65 g of the supported mixed rare earth carbonate catalyst was added, and the mixture was heated under reflux for 12 hours. After cooling, the catalyst was recovered by filtration, and the solvent was removed by distillation under reduced pressure to obtain the crude product of the ultraviolet absorber UV-3030. The crude product was dissolved in a mixed solvent of 87 mL of tetrachloroethylene and ethyl acetate (1:0.5, V / V), and crystallization was carried out in an ice-salt bath for 12 hours. The solvent was removed by filtration, and the solvent was removed by heating to the molten state to obtain 25.5 g of the refined product of UV3030. The content detected by liquid chromatography was 99.3%. The product yield calculated based on UV-3035 was 86.1%.

[0036] Example 6

[0037] 46.4 g of UV-3035 and 3.8 g of pentaerythritol (6:1 mol / mol) were dissolved in 47 mL of diethylformamide. 7 g of the supported mixed rare earth carbonate catalyst was added, and the mixture was heated under reflux for 12 hours. After cooling, the catalyst was recovered by filtration, and the solvent was removed by distillation under reduced pressure to obtain the crude product of the ultraviolet absorber UV-3030. The crude product was dissolved in a mixed solvent of 93 mL of tetrachloroethylene and ethyl acetate (1:0.5, V / V), and crystallization was carried out in an ice-salt bath for 12 hours. The solvent was removed by filtration, and the solvent was removed by heating to the molten state to obtain 25.4 g of the refined product of UV3030. The content detected by liquid chromatography was 99.1%. The product yield calculated based on UV-3035 was 85.8%.

[0038] Example 7

[0039] The same feeding amount and operation process as in Example 1 were used, except that the amount of diethylformamide was changed to 20 mL. After recrystallization, 23.8 g of the refined product of UV-3030 was obtained. The content detected by liquid chromatography was 99.2%. The product yield calculated based on UV-3035 was 80.4%.

[0040] Example 8

[0041] The same feeding amount and operation process as in Example 1 were used, except that the amount of diethylformamide was changed to 60 mL. After recrystallization, 25.5 g of the refined product of UV-3030 was obtained. The content detected by liquid chromatography was 99.6%. The product yield calculated based on UV-3035 was 86.1%.

[0042] Example 9

[0043] The same feeding amount and operation process as in Example 1 were used, except that the amount of diethylformamide was changed to 80 mL. After recrystallization, 25.8 g of the refined product of UV-3030 was obtained. The content detected by liquid chromatography was 99.7%. The product yield calculated based on UV-3035 was 87.1%.

[0044] Example 10

[0045] The feeding amount and operation process are the same as those in Example 1, except that the dosage of the supported mixed rare earth carbonate catalyst is changed to 0.2 g. After recrystallization, 20.3 g of refined UV-3030 product is obtained, and the content detected by liquid chromatography is 99.1%. The product yield calculated based on UV-3035 is 68.6%.

[0046] Example 11

[0047] The feeding amount and operation process are the same as those in Example 1, except that the dosage of the supported mixed rare earth carbonate catalyst is changed to 0.4 g. After recrystallization, 23.9 g of refined UV-3030 product is obtained, and the content detected by liquid chromatography is 99.3%. The product yield calculated based on UV-3035 is 80.7%.

[0048] Example 12

[0049] The feeding amount and operation process are the same as those in Example 1, except that the dosage of the supported mixed rare earth carbonate catalyst is changed to 0.8 g. After recrystallization, 25.6 g of refined UV-3030 product is obtained, and the content detected by liquid chromatography is 99.5%. The product yield calculated based on UV-3035 is 86.5%.

[0050] Example 13

[0051] The feeding amount and operation process are the same as those in Example 1, except that the reflux reaction time is changed to 8 hours. After recrystallization, 22.4 g of refined UV-3030 product is obtained, and the content detected by liquid chromatography is 98.3%. The product yield calculated based on UV-3035 is 75.7%.

[0052] Example 14

[0053] The feeding amount and operation process are the same as those in Example 1, except that the reflux reaction time is changed to 10 hours. After recrystallization, 24.2 g of refined UV-3030 product is obtained, and the content detected by liquid chromatography is 99.0%. The product yield calculated based on UV-3035 is 81.8%.

[0054] Example 15

[0055] The feeding amount and operation process are the same as those in Example 1, except that the reflux reaction time is changed to 14 hours. After recrystallization, 25.4 g of refined UV-3030 product is obtained, and the content detected by liquid chromatography is 99.4%. The product yield calculated based on UV-3035 is 85.8%.

[0056] Example 16

[0057] The feeding amount and operation process were the same as those in Example 1, except that the reflux reaction time was changed to 16 hours. After recrystallization, 25.1 g of refined UV-3030 product was obtained, and the content detected by liquid chromatography was 99.2%. The product yield calculated based on UV-3035 was 84.8%.

[0058] It is not difficult to see from the above examples that when the molar ratio of UV-3035 to pentaerythritol is (4-6):1, the volume of diethylformamide used is 0.5-2 times the mass of UV-3035, and the amount of supported mixed rare earth carbonate catalyst used is 0.5-2% of the mass of UV-3035, a product with a high yield can be obtained when the reflux time is 8-16 hours, and the purification process is simple, which is suitable for industrial production. Considering production efficiency, the reflux reaction time of 8-12 hours is preferably selected. In the prior art, when UV-3035 and pentaerythritol are used to prepare UV-3030 with lithium hydroxide or organotin oxide as the catalyst under solvent-free and vacuum conditions, the product yield is less than 70%. In comparison, this solution has significant advantages in many aspects.

[0059] Experimental Example

[0060] With the same feeding amount and operation process as in Example 1, the supported mixed rare earth carbonate catalyst recovered by filtration was recycled to prepare UV-3030, and the experimental results are shown in Table 1.

[0061] Table 1: Experimental Results of Catalyst Recovery

[0062] Catalyst Refined product quantity (g) Purity (%) New catalyst 25.2 99.6 Recycled catalyst for the first time 25.1 99.4 Recycled catalyst for the second time 25.3 99.5 Recycled catalyst for the third time 25.0 99.4 Recycled catalyst for the fourth time 25.1 99.6 Recycled catalyst for the fifth time 24.9 99.3

[0063] It is not difficult to see from Table 1 that when the supported mixed rare earth carbonate catalyst is used for catalysis and recycled different times, it still has high catalytic activity and selectivity. Compared with the expensive lithium hydroxide or organotin oxide catalysts in the prior art, it can avoid the defect of difficult recovery and has significant industrial application prospects.

[0064] Although the embodiments of the present invention have been shown and described, for those of ordinary skill in the art, it can be understood that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A synthetic method of ultraviolet absorber UV-3030, characterized in that, It includes the following steps: Dissolve UV-3035 and pentaerythritol in N,N-diethylformamide, add the supported mixed rare earth carbonate catalyst, and then carry out a reflux reaction. The reaction product is filtered and purified to obtain UV-3030; The supported mixed rare earth carbonate catalyst is obtained by suspending ZSM-11 molecular sieve in lanthanum chloride solution, adding ammonium bicarbonate under stirring, allowing it to stand to obtain a precipitate, filtering the precipitate, washing it with water, drying it, and then calcining it at 200 °C for 2 hours; The particle size of the ZSM-11 molecular sieve is 0.5 - 2 mm; the mass ratio of the ZSM-11 molecular sieve to lanthanum chloride and ammonium bicarbonate is 10:1:1.

5.

2. The synthesis method according to claim 1, wherein, The molar ratio of UV-3035 to pentaerythritol is (4 - 6):

1.

3. The synthesis method according to claim 1, wherein The dosage of N,N-diethylformamide is 0.5 - 2 times (V / W) that of UV-3035.

4. The synthesis method according to claim 1, characterized in that, The addition amount of the supported mixed rare earth carbonate catalyst is 0.5 - 2% of the mass of UV-3035.

5. The synthesis method according to claim 1, characterized in that, The reflux reaction time is 8 - 12 hours.

6. The synthesis method according to claim 1, wherein The supported mixed rare earth carbonate catalyst is recovered during the filtration process and recycled for catalytic reaction more than 5 times.

7. The synthesis method according to claim 1, characterized in that, In the purification process, recrystallization is carried out using a mixed solution of tetrachloroethylene and ethyl acetate. The volume ratio of tetrachloroethylene to ethyl acetate is 1:0.5, and the volume of the mixed solution is 2 times the mass of UV-3035.