38103-06-9Relevant articles and documents
METHODS OF MANUFACTURE OF DIANHYDRIDES
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Page/Page column 23, (2021/12/31)
A method of making dianhydride includes contacting a N-Substituted diimide with a carboxylic acid and substituted or unsubstituted dimethyl sulfoxide in an aqueous medium to provide a reaction mixture including tetra acid, triacid, imide diacid and diimide along with substituted or unsubstituted acetic acid, dimethyl sulfoxide and their derivatives. The method includes the isolation of tetra acid by precipitation in water followed by centrifuge or filtration. The tetra acid is converted into the corresponding dianhydride. The dianhydride prepared by the method are also described as precursor to make polyetherimide.
Preparation method of aromatic diether dianhydride
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Paragraph 0051; 0054; 0063; 0066, (2019/12/02)
The invention relates to a preparation method of aromatic diether dianhydride, which comprises the following steps: (1) pouring a bisphenol compound, N-substituted phthalimide and a catalyst into a mixed solvent, carrying out heating reflux to remove water and carrying out substitution reaction to obtain N-substituted diether imide; (2) adding alkali metal hydroxide and water into the N-substituted diether imide obtained in the step (1), heating the mixture, carrying out hydrolysis reaction, cooling, adding protonic acid, separating out solid, collecting the solid, and drying the solid; and (3) dissolving the dried solid in a mixed solution of acetic acid and acetic anhydride, carrying out heating reflux, cooling, filtration and solid collection in sequence, recrystallizing the collected solid with a mixed solution of acetonitrile and toluene, performing filtration, collecting the solid, and drying the solid to obtain the product. The preparation method of the aromatic diether dianhydride has the advantages that the steps are simplified, the consumed time is short, the used solvent is easy to recycle and can be repeatedly used, and the prepared product aromatic diether dianhydrideis high in purity and yield.
Method for preparing bisphenol A diether dianhydride
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Paragraph 0011; 0012; 0014, (2018/07/15)
The invention relates to a method for preparing bisphenol A diether dianhydride. The method comprises the following steps that: the molar ratio of sodium hydroxide to bisphenol A is (2.1-2.3) to 1, the molar ratio of 4-chlorophthalic anhydride to phenol A is (2-2.1) to 1, the weight of a catalyst benzyl triethyl ammonium chloride is 15% by weight of the weight of bisphenol A, and the amount of a solvent trimethylbenzene is 8 times larger than the weight of bisphenol A; the preparation process is as follows: adding an aqueous solution of sodium hydroxide and bisphenol A to areactor, heating, stirring and dissolving at a temperature, heating to 85 DEG C to 90 DEG C, adding the trimethylbenzene and benzyl triethyl ammonium chloride which accounts 46% by weight of the total weight, heating toreflux, dewatering, stirring at a temperature of 172 DEG C and reacting for 15 to 18 hours, cooling to 130 DEG C, adding 4-chlorophthalic anhydride and benzyl triethyl ammonium chloride which accounts54% by weight of the total weight, heating 140 DEG C to 145 DEG C, performing a reflux reaction for 5 to 6 hours, filtering while hot, cooling a filtrate to room temperature, filtering, washing a precipitate with deionized water and ethanol respectively, filtering to obtain a wet material, and drying to obtain a bisphenol A diether dianhydride product with a yield of 80 to 85%. .