A method for preparing 9,9-bis(trifluoromethyl)xanthenetetracarboxylic dianhydride

Abstract

The invention provides a method for preparing 9,9-bis(trifluoromethyl)xanthene tetracarboxylic dianhydride, comprising the steps of: adding 4-hydroxyphthalic anhydride, hexafluoroacetone, p-toluenesulfonic acid, a solvent, and a perfluorosulfonic acid resin silica support to a reaction bottle, heating the reaction for a period of time, and performing post-processing to obtain 9,9-bis(trifluoromethyl)xanthene tetracarboxylic dianhydride. A method for preparing 9,9-bis(trifluoromethyl)xanthene tetracarboxylic dianhydride of the present invention has the advantages of short reaction steps, easy purchase of raw materials and low cost, simple post-processing operation, high yield, high product purity, less environmental pollution, and recyclable acidic substances.

Description

Technical Field

[0001] The invention belongs to the technical field of material raw material preparation, and in particular relates to a method for preparing 9,9-bis(trifluoromethyl)xanthenetetracarboxylic dianhydride. Background Art

[0002] Fluorinated polyimide (FPI) is a rigid polymer with an imide ring in the main chain and a highly regular chemical structure. It is a polymer material obtained by the melt polycondensation or solution polycondensation reaction of fluorinated dianhydride and fluorinated diamine to generate fluorinated polyamic acid (FPAA), and then imidization. FPI has good light transmittance, better heat and oxygen aging resistance than most PIs, and a dielectric constant of less than 3, which is the type with the lowest dielectric constant in the PI series. FPI is widely used in high-tech fields such as aerospace, electronic power, and precision machinery, including special plastics, composite materials, films, adhesives, fibers, liquid crystal orientation agents, separation membranes, photoresists, etc., and has become an irreplaceable high-performance polymer material. As a new type of fluorinated dianhydride monomer, 9,9-bis(trifluoromethyl)-2,3,6,7-oxa-anthraquinone tetracarboxylic dianhydride (6FCDA) has good application prospects.

[0003] At present, there are few literatures on the synthesis of 9,9-bis(trifluoromethyl)-2,3,6,7-oxanthracene tetracarboxylic dianhydride, and even fewer methods suitable for production:

[0004] 1) Trofimenko S. 9,9-bis(perfluroralkyl)xanthene,9-aryl-9-perfluroralkylxanthene: US, US5051520 A[P].1991.

[0005] 2) Li Nanwen, Xu Hui. A method for synthesizing tetracarboxylic dianhydride with fluorinated rigid structure, CN111303183A[P].2020.

[0006] These two articles disclose that 3,4-dimethylphenol and hexafluoroacetone are used as starting materials and 9,9-bis(trifluoromethyl)-2,3,6,7-tetramethyloxanthene is obtained by catalyzing the reaction with a fluorine-containing strong acid, and then the above product is oxidized with potassium permanganate to obtain 9,9-bis(trifluoromethyl)-2,3,6,7-oxanthene tetracarboxylic acid, and finally dehydrated into anhydride to obtain 9,9-bis(trifluoromethyl)-2,3,6,7-oxanthene tetracarboxylic dianhydride. The fluorine-containing strong acid used in this method increases the difficulty of post-treatment, and the total yield of the three-step reaction is less than 30%. Oxidation with potassium permanganate will also form a large amount of waste solids and wastewater, which are difficult to handle. These reasons make it impossible to produce in large quantities.

[0007] 3) Hu Guoyi, Hu Jinping, Wu Jianhua, et al. Synthesis of 9,9-bis(trifluoromethyl)-2,3,6,7-oxanthene tetracarboxylic dianhydride:, CN114133403A[P].2022

[0008] The article published a method of using 4,4'-biphenyl ether dianhydride as the starting material, esterifying it with hexafluoroacetone in the presence of concentrated sulfuric acid to obtain 9,9-bis(trifluoromethyl)-2,3,6,7-oxanthene tetracarboxylic acid tetraester, and then hydrolyzing the above product with alkali to obtain 9,9-bis(trifluoromethyl)-2,3,6,7-oxanthene tetracarboxylic acid, which was finally dehydrated to anhydride to obtain 9,9-bis(trifluoromethyl)-2,3,6,7-oxanthene tetracarboxylic dianhydride. Although this method avoids the use of fluorine-containing strong acid and increases the total yield to about 60%, the route becomes four steps, and strong acid is still used as a catalyst, which increases the difficulty of waste liquid treatment.

[0009] The existing disclosed 6FCDA synthesis process technology requires a large amount of strong acid as a catalyst, the overall yield is low, and it is not suitable for mass production. These methods have different degrees of limitations in the application of industrial production. Therefore, it is urgent to find a suitable method for preparing 6FCDA industrially. Summary of the invention

[0010] In view of this, the present invention aims to provide a method for preparing 9,9-bis(trifluoromethyl)xanthenetetracarboxylic dianhydride, which has the advantages of short reaction steps, relatively mild conditions, relatively low raw material cost, simple post-treatment operation, high yield, and high product purity.

[0011] To achieve the above object, the technical solution of the present invention is achieved as follows:

[0012] A method for preparing 9,9-bis(trifluoromethyl)xanthenetetracarboxylic dianhydride comprises the following steps: adding 4-hydroxyphthalic anhydride, hexafluoroacetone, p-toluenesulfonic acid, a solvent, and a perfluorosulfonic acid resin silica support into a reaction bottle, heating the reaction for a period of time, and performing post-treatment to obtain the prepared 9,9-bis(trifluoromethyl)xanthenetetracarboxylic dianhydride.

[0013] The molar ratio of 4-hydroxyphthalic anhydride, hexafluoroacetone, p-toluenesulfonic acid and aprotic solvent is 1:0.49:1.1:5-11, preferably the molar ratio of 4-hydroxyphthalic anhydride, hexafluoroacetone, p-toluenesulfonic acid and o-dichlorobenzene is 1:0.49:1.1:5.3.

[0014] The mass ratio of 4-hydroxyphthalic anhydride to the perfluorosulfonic acid resin catalyst is 1:0.10-0.40, preferably, the mass ratio of 4-hydroxyphthalic anhydride to the 20% perfluorosulfonic acid resin silica support is 1:0.25.

[0015] Perfluorosulfonic acid resin catalysts include 10% perfluorosulfonic acid resin silica loading, 20% perfluorosulfonic acid resin silica loading, 30% perfluorosulfonic acid resin silica loading, 40% perfluorosulfonic acid resin silica loading,

[0016] The load is one of toluene, o-dichlorobenzene, dioxane and DCE solution. Preferably, the load is toluene.

[0017] The aprotic solvent includes one of toluene, o-dichlorobenzene, dioxane, and DCE solution. Preferably, the aprotic solvent is toluene.

[0018] The temperature of the temperature-raising reaction is 90-140°C, preferably, the temperature is 130-135°C.

[0019] The post-treatment includes cooling to a certain temperature, filtering, cooling the filtrate to room temperature, filtering, stirring the filter cake with solvent heat, and suction filtering to obtain 9,9-bis(trifluoromethyl)xanthenetetracarboxylic dianhydride.

[0020] The cooling temperature is 80-90°C, and the solvent is one of tetrahydrofuran or acetonitrile.

[0021] The post-treatment includes hot filtration, cooling the filtrate, and filtration to obtain 9,9-bis(trifluoromethyl)xanthenetetracarboxylic dianhydride.

[0022] Compared with the prior art, the method for preparing 9,9-bis(trifluoromethyl)xanthenetetracarboxylic dianhydride of the present invention has the following beneficial effects:

[0023] The invention has the advantages of short reaction steps, easy purchase of raw materials with low cost, simple post-processing operation, high yield, high product purity, less environmental pollution, and recyclable acidic substances. DETAILED DESCRIPTION

[0024] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments may be combined with each other.

[0025] The present invention will be described in detail below with reference to examples.

[0026] Example 1

[0027] To a sealed reaction bottle, add 100.00 g (0.61 mol) of 4-hydroxyphthalic anhydride, 49.57 g (0.30 mol) of hexafluoroacetone, 115.42 g (0.67 mol) of p-toluenesulfonic acid, 474.72 g (3.23 mol) of o-dichlorobenzene, and 125 g of 20% perfluorosulfonic acid resin silica support. Heat to 130-135 ° C, react for 5 h, turn off the heating, cool to 80 ° C, filter, cool the filtrate to room temperature, filter, heat the filter cake with acetonitrile and stir, and filter to obtain 115.75 g of white solid with a yield of 84.61% and a purity of 99.71%.

[0028] Example 2

[0029] To a sealed reaction bottle, add 80.00 g (0.49 mol) of 4-hydroxyphthalic anhydride, 39.66 g (0.24 mol) of hexafluoroacetone, 92.33 g (0.54 mol) of p-toluenesulfonic acid, 474.72 g (3.28 mol) of toluene, and 60 g of 40% perfluorosulfonic acid resin silica support, heat to 110-115°C, react for 12 h, turn off the heating, cool to 90°C, filter, cool the filtrate to room temperature, filter, stir the filter cake with hot tetrahydrofuran, and filter to obtain 73.67 g of a white solid with a yield of 67.31% and a purity of 97.35%.

[0030] Example 3

[0031] To a sealed reaction bottle, add 55.00 g (0.34 mol) of 4-hydroxyphthalic anhydride, 27.26 g (0.16 mol) of hexafluoroacetone, 63.48 g (0.37 mol) of p-toluenesulfonic acid, 309.9 g (3.51 mol) of dioxane, and 5.5 g of perfluorosulfonic acid resin. Raise the temperature to 95-100 ° C. and react for 16 h. Turn off the heating, filter hot, cool the filtrate, and filter to obtain 55.78 g of a white solid with a yield of 74.13% and a purity of 98.56%.

[0032] Table 1 Perfluorosulfonic acid resin catalyst

[0033]

[0034] Table 2 Effect of perfluorosulfonic acid resin catalyst on the reaction

[0035]

Claims

1. A method for preparing 9,9-bis(trifluoromethyl)xanthenetetracarboxylic dianhydride, Features: The method comprises the following steps: adding 4-hydroxyphthalic anhydride, hexafluoroacetone, p-toluenesulfonic acid, a non-protonic solvent and a perfluorosulfonic acid resin silica carrier into a reaction bottle, heating the reaction for a period of time, and performing post-treatment to prepare 9,9-bis(trifluoromethyl)xanthenetetracarboxylic dianhydride.

2. A method for preparing 9,9-bis(trifluoromethyl)xanthenetetracarboxylic dianhydride according to claim 1, Features: The molar ratio of 4-hydroxyphthalic anhydride, hexafluoroacetone, p-toluenesulfonic acid and aprotic solvent is 1:0.49:1.1:5-11.

3. A method for preparing 9,9-bis(trifluoromethyl)xanthenetetracarboxylic dianhydride according to claim 1, Features: The molar ratio of 4-hydroxyphthalic anhydride, hexafluoroacetone, p-toluenesulfonic acid, and aprotic solvent is 1:0.49:1.1:5.

3.

4. A method for preparing 9,9-bis(trifluoromethyl)xanthenetetracarboxylic dianhydride according to claim 1, Features: The mass ratio of 4-hydroxyphthalic anhydride to perfluorosulfonic acid resin silica loading is 1:0.10-0.

40.

5. A method for preparing 9,9-bis(trifluoromethyl)xanthenetetracarboxylic dianhydride according to claim 1, Features: The perfluorosulfonic acid resin silica loading material is 20% perfluorosulfonic acid resin silica loading material; The mass ratio of 4-hydroxyphthalic anhydride to 20% perfluorosulfonic acid resin silica loading is 1:0.

25.

6. A method for preparing 9,9-bis(trifluoromethyl)xanthenetetracarboxylic dianhydride according to claim 1, Features: The perfluorosulfonic acid resin silica loading material includes 10% perfluorosulfonic acid resin silica loading material, 20% perfluorosulfonic acid resin silica loading material, 30% perfluorosulfonic acid resin silica loading material, and 40% perfluorosulfonic acid resin silica loading material.

7. A method for preparing 9,9-bis(trifluoromethyl)xanthenetetracarboxylic dianhydride according to claim 1, Features: The aprotic solvent is one of toluene, o-dichlorobenzene, dioxane, and DCE solution.

8. A method for preparing 9,9-bis(trifluoromethyl)xanthenetetracarboxylic dianhydride according to claim 7, Features: The aprotic solvent was toluene.

9. A method for preparing 9,9-bis(trifluoromethyl)xanthenetetracarboxylic dianhydride according to claim 1, Features: The temperature of the heating reaction is 90~140℃.

10. A method for preparing 9,9-bis(trifluoromethyl)xanthenetetracarboxylic dianhydride according to claim 9, Features: The temperature is 130~135℃.

11. A method for preparing 9,9-bis(trifluoromethyl)xanthenetetracarboxylic dianhydride according to claim 1, Features: The post-treatment includes cooling to a certain temperature, filtering, cooling the filtrate to room temperature, filtering, stirring the filter cake with solvent heat, and suction filtering to obtain 9,9-bis(trifluoromethyl)xanthenetetracarboxylic dianhydride.

12. A method for preparing 9,9-bis(trifluoromethyl)xanthenetetracarboxylic dianhydride according to claim 11, Features: The cooling temperature is 80-90°C, and the solvent is one of tetrahydrofuran or acetonitrile.

13. A method for preparing 9,9-bis(trifluoromethyl)xanthenetetracarboxylic dianhydride according to claim 1, Features: The post-treatment includes hot filtration, cooling the filtrate, and filtration to obtain 9,9-bis(trifluoromethyl)xanthenetetracarboxylic dianhydride.

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