- Preparation method of aromatic diether dianhydride
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The invention discloses a preparation method of aromatic diether dianhydride, which comprises the following steps of: by using isobutene or tert-butyl alcohol as a protecting group of carboxyl of chlorinated or nitrophthalic acid, carrying out etherification reaction with disodium bisphenol salt to obtain an intermediate, removing the tert-butyl ester protecting group in the intermediate by usinga small amount of acid without strong alkali treatment to obtain diether tetracarboxylic acid, and finally, enabling the solid tetracarboxylic acid to directly form anhydride at a proper temperature,wherein acetic anhydride dehydration is not needed, and the reaction time of the whole process is only about 21 hours. The preparation method of the aromatic diether dianhydride is short in reaction period, simple and safe in process, high in production efficiency and low in production cost.
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Paragraph 0025; 0029; 0034-0035; 0040
(2021/02/06)
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- METHODS OF MANUFACTURE OF DIANHYDRIDES
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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.
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- Preparation method of aromatic diether dianhydride
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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.
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- METHOD FOR PRODUCING AN AROMATIC DIANHYDRIDE
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A method for producing an aromatic dianhydride includes reacting an aromatic diimide with a substituted or unsubstituted phthalic anhydride in an aqueous medium in the presence of an amine exchange catalyst to provide an aqueous reaction mixture including an N-substituted phthalimide, an aromatic tetraacid salt, and at least one of an aromatic triacid salt and an aromatic imide diacid salt. The method further includes removing the phthalimide from the aqueous reaction mixture by extracting the aqueous reaction mixture with an organic solvent and converting to the corresponding aromatic dianhydride. The extracting is carried out in an extraction column including a high specific surface area metal packing material and having an interface between the aqueous reaction mixture and the organic solvent that is at a level that is 14 to 85 % of the height of the extraction column.
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Paragraph 0043
(2019/12/28)
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- Method for preparing bisphenol A diether dianhydride
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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%. .
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Paragraph 0011; 0012; 0014
(2018/07/15)
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- Direct dianhydride synthesis
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This invention is related to a method for making diether dianhydrides by the reaction of halophthalic anhydride and a metal salt of an aromatic dihydroxy compound in the presence of a solvent and a phase transfer catalyst. Typical phase transfer catalyst include guanidium salts, aminopyridinium salts, or phosphazenium salts.
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Page/Page column 6
(2008/06/13)
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- A comparison of poly(ether imide)s with 3-phthalimide and 4-phthalimide units: Synthesis, characterization, and physical properties
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Bis(ether anhydride)s with 3- or 4-phthalimide moieties were prepared by reacting 3- or 4-nitrophthalodinitrile, respectively, with several diols and converting the resulting bis(ether dinitrile)s to bis(ether anhydride)s. Selected dianhydrides were converted into poly(ether imide)s in a two-stage solution polymerization and imidization process. It was found that, in most cases, the dianhydrides with 4-phthalic anhydride units gave high-molecular-weight polymers with any of several aromatic diamines. In contrast, dianhydrides with 3-phthalic anhydride units gave, primarily, low-molecular-weight products. Examination of several low-molecular-weight products by electrospray-ionization mass spectrometry demonstrated that the products consisted of small oligomers, cyclic or linear according to the structure of the diamine. A series of high-molecular-weight polymers were prepared from 4,4′-bis(4″-aminophenoxy)biphenyl (BAPB) and each of several bis(ether anhydride)s with 3- or 4-phthalic anhydride units; the anhydrides had isopropylidine or hexafluoroisopropylidine units or ortfto-methyl or ortho-tert-butyl substituents in the diol residues. These polymers were characterized in terms of their molecular weights and glass-transition temperatures. The gas permeabilities, positron annihilation, and dielectric relaxation behaviors of the polymers were investigated and their properties related to their molecular structures. Dielectric relaxation spectroscopy measurements indicate that, in this group of polymers, the rates of the local chain mobility are comparable and are able to facilitate gas diffusion. An apparent linear correlation between the permeation coefficients and free volume as determined by positron annihilation lifetime spectroscopy was observed with certain gases. Comparison of polymers with similar molecular structures indicated that isomeric polymers with 3- and 4-linked phthalimide units have similar properties and that the introduction of branched chains or fluorinated groups leads to an increase in the free volume and consequently increased permeability.
- Eastmond,Paprotny,Pethrick,Santamaria-Mendia
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p. 7534 - 7548
(2007/10/03)
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- Polyetherimides for gas separation membranes
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A series of polyetherimides were synthesized by polycondensation reaction at high temperature of 2,2-bis[4,4-(3,4-dicarboxyphenoxy) phenyl]propane dianhydride with various aromatic diamines. These polymers are easy soluble in polar aprotic solvents such as N-methylpyrrolidinone, dimethylformamide or dimethylacetamide or even in less polar liquids such as chloroform. They show high thermal stability, with decomposition temperature being above 400°C and glass transition temperature in the range 200-275°C. Polymer solutions in chloroform were processed into thin films which were tested as gas separation membranes. Transport parameters for light gases were measured. The dependence of glass transition and decomposition temperature on conformational rigidity parameters was calculated.
- Bruma,Hamciuc,Yampolskii,Alentiev,Ronova,Rojkov
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p. 11/[739]-19/[747]
(2007/10/03)
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