- A new synthetic route of 4,4′-hexafluoroisopropylidene-2, 2-bis-(phthalic acid anhydride) and characterization of 4,4′-hexafluoroisopropylidene-2,2-bis-(phthalic acid anhydride)-containing polyimides
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The title product 4,4′-hexafluoroisopropylidene-2,2-bis-(phthalic acid anhydride) was prepared from hexafluoroacetone and o-xylene as the starting materials by condensation, oxidation and dehydration three-step reaction sequence. It reacted with diamines in DMF or xylene to give polyimides by condensation polymerization. Thermal and viscosity analyses show that these polyimides have lower molecular weight but excellent thermal stability.
- Zhu, Shi-Zheng,Zhao, Jing-Wei,Zhang, Yun-Xiang
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- Method for preparing polyimide monomer having low yellow index
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The present invention chemically synthesizes a polyimide monomer. 10. The synthesized polyimide monomer is introduced into the loading area of the sublimation purification apparatus. - 3 TTTorr under vacuum above sublimation temperature of the synthesized polyimide monomer, followed by recrystallization. Provided is a method for preparing a polyimide monomer having improved yellowness index.
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Paragraph 0041; 0080-0081
(2021/11/02)
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- Preparation method of hexafluorodianhydride
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The invention relates to the field of preparation of fluorine-containing monomers, and particularly discloses a preparation method of hexafluorodianhydride. The preparation method comprises the following steps: S1, preparation of hexafluorotetracid according to the following reaction process flow: step (1), with o-dichlorobenzyl and hexafluoroacetone used as raw materials, adding a catalyst, and performing stirring reflux at 130-150 DEG C for 20-40 h to obtain a product a; step (2), hydrolyzing the product a into a product b under an alkaline condition; step (3), oxidizing a hydroxyl group into an aldehyde group to obtain a product c; and step (4), oxidizing the aldehyde group into a carboxyl group to obtain hexafluorotetracid; and S2, preparation of hexafluorodianhydride according to the reaction process flow that hexafluorotetracid is dehydrated and anhydridized to prepare hexafluorodianhydride. Compared with the prior art, the preparation method provided by the invention has the advantages that reaction conditions in the whole process are mild, the use of a potassium permanganate strong oxidant is avoided in a route, requirements on a reaction container are lower, and reaction safety is higher.
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- Synthesis method of 4, 4-(hexafluoroisopropenyl) diphthalic anhydride
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The invention belongs to the technical field of synthesis of 4, 4-(hexafluoroisopropenyl) diphthalic anhydride, in particular to a synthesis method of 4, 4-(hexafluoroisopropenyl) diphthalic anhydride. The synthesis method has the advantages of easy separation of intermediate products, high yield, less waste and good economic benefit, and a mixed solvent of isobutanol and butyl acetate is adoptedto reduce the solubility of the product, facilitate the separation of the product and increase the yield. Besides, the Pd/C catalyst is pretreated, a proper amount of sulfide is added for pretreatment, the sulfur poisoning resistance of the catalyst is improved, the service life of the catalyst is prolonged, and the application frequency of the catalyst is increased; because nitro compounds contain trace amount of sulfides such as sulfuric acid and like, catalyst is easily poisoned. In the step 2, an alumina-silica gel catalyst is added so that 2, 2-bis (3-amino-4-hydroxyphenyl) molecules canbe adsorbed on the surface of the catalyst in a flat shape, hydroxyl is closer to the surface of the catalyst, and the amination reaction of hydroxyl is facilitated; in the step 4, a small amount of urea is added in the cyanolysis reaction to prevent diazonium salt from being oxidized, becoming tar and other side reactions.
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- Synthesis process of 4, 4-(hexafluoroisopropenyl) diphthalic anhydride
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The invention belongs to the technical field of synthesis of 4, 4-(hexafluoroisopropenyl) diphthalic anhydride, in particular to a synthesis process of 4, 4-(hexafluoroisopropenyl) diphthalic anhydride. The synthesis process has the advantages of easy separation of intermediate products, high yield, less waste and good economic benefit, adopts a mixed solvent of long-chain alcohol and ester, reduces the solubility of the product, is beneficial to product separation, and has higher yield. Besides, the Pd/C catalyst is pretreated, a proper amount of sulfide is added for pretreatment, the sulfurpoisoning resistance of the catalyst is improved, the service life of the catalyst is prolonged, and the application frequency of the catalyst is increased; because nitro compounds contain trace amount of sulfides such as sulfuric acid and like, catalyst is easily poisoned. In the step 2, an alumina-silica gel catalyst is added so that 2, 2-bis (3-amino-4-hydroxyphenyl) molecules can be adsorbed on the surface of the catalyst in a flat shape, hydroxyl is closer to the surface of the catalyst, and the amination reaction of hydroxyl is facilitated; in the step 4, a small amount of urea is addedin the cyanolysis reaction to prevent diazonium salt from being oxidized, becoming tar and other side reactions.
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- Preparation method of 4, 4 '-(hexafluoroisopropylidene) diphthalic anhydride
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The invention discloses a preparation method of 4, 4 '-(hexafluoroisopropylidene) diphthalic anhydride. The method comprises the following steps of (a) accurately weighing N-alkyl phthalimide and a catalyst, stirring and raising the temperature to 90-110 DEG C, and dissolving; slowly dropwise adding hexafluoroacetone hydrate, raising the temperature to 100 to 130 DEG C, reacting for 22 to 80 hourswhile stirring, and discharging to obtain 4, 4-(hexafluoroisopropyl) bis (N-alkyl phthalimide); (b) adding alkali to hydrolyze, and acidifying to obtain hexafluorotetracid; and (c) dehydrating to obtain the 4, 4 '-(hexafluoroisopropylidene) diphthalic anhydride. According to the preparation method, the hexafluoroacetone and specific N-alkyl phthalimide directly react under the action of a specific catalyst to prepare hexafluorodianhydride, the step of oxidizing methyl in a traditional method is omitted, the use of metal oxides is avoided, the environmental pollution is small, a normal-pressure reaction is adopted, a high-pressure reaction is not needed, the reaction risk is reduced, the purity of the prepared 4, 4 '-(hexafluoroisopropylidene) diphthalic anhydride is high, and the yield reaches 87% or above.
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- Preparation process of 4, 4-(hexafluoroisopropenyl) diphthalic anhydride
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The invention belongs to the technical field of synthesis of 4, 4-(hexafluoroisopropenyl) diphthalic anhydride, in particular to a preparation process of 4, 4-(hexafluoroisopropenyl) diphthalic anhydride. The preparation process has the advantages of easy separation of intermediate products, high yield, fewer wastes and favorable economic benefit, and adopts a mixed solvent of amyl alcohol and butyl acetate to lower the solubility of the product, thereby being beneficial to product separation and higher yield. Besides, the Pd/C catalyst is pretreated, a proper amount of sulfide is added for pretreatment, the sulfur poisoning resistance of the catalyst is improved, the service life of the catalyst is prolonged, and the application frequency of the catalyst is increased; because nitro compounds contain trace amount of sulfides such as sulfuric acid and like, catalyst is easily poisoned. In the step 2, an alumina-silica gel catalyst is added so that 2, 2-bis (3-amino-4-hydroxyphenyl) molecules can be adsorbed on the surface of the catalyst in a flat shape, hydroxyl is closer to the surface of the catalyst, and the amination reaction of hydroxyl is facilitated; in the step 4, a small amount of urea is added in the cyanolysis reaction to prevent diazonium salt from being oxidized, becoming tar and other side reactions.
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Paragraph 0013-0014
(2020/09/09)
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- Method for preparing hexafluorodianhydride under mild condition
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The invention discloses a method for preparing hexafluorodianhydride under a mild condition. The method comprises the steps of: a) preparing hexafluoro-orthophenyl tetranitrile: dissolving phthalic nitrile in hexafluoroacetone trihydrate, adding a catalyst, introducing nitrogen for shielding, and performing reflux for 50-70 h under a stirring condition at 150-160 DEG C, b) hydrolyzing hexafluoro-orthophenyl tetranitrile to generate hexafluoro-tetracid: adding alkali, water and methanol into pure hexafluoro-orthophenyl tetranitrile obtained in the step a), and performing reflux for 30-50 h at 100-120 DEG C, and c) adding methylbenzene and acetic anhydride into hexafluoro-tetracid obtained in the step b) and performing reflux for 8-12 h at 110-130 DEG C. According to the method, liquid hexafluoroacetone trihydrate is used in the step a); the toxicity and operation difficulty are reduced; in addition, strong corrosion and high risk anhydrous hydrofluoric acid is not used; requirements onequipment and recovery are low; the method is more environmentally friendly; hydrolysis and acidification treatment are used in the step b); a strong oxidation compound is not used; and the productionoperation requirements are low.
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- 4. 4' - (six fluorine Asia isopropyl) two neighbouring benzene phthalic anhydride synthesis method (by machine translation)
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The invention belongs to the field of organic synthetic technology, in particular to a 4, 4' - (six fluorine Asia isopropyl) two neighbouring benzene phthalic anhydride synthesis method. The method comprises the following steps: (1) the 4, 4' - (six fluorine Asia isopropyl) II O-xylene in the heating oxidation under the action of the potassium permanganate, make six fluorine four acid; (2) will be six fluorine four acid added to the xylene with acetic anhydride in the mixed solvent of heating and stirring, after the reaction, the post-treatment. This method reduces the oxidation reaction in the consumption of potassium permanganate and adding times, shortens the reaction time, simplifies the operation steps; to avoid the use of the inorganic alkali, is conducive to the improvement of the potassium permanganate oxidation, but also reduce the cost; improved dehydration method, reduce the reaction temperature, shortens the reaction time, improves the six fluorine four acid into six fluorine two bitter wine efficiency, and the purity is as high as 99.5%. (by machine translation)
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Paragraph 0026; 0027; 0028; 0029; 0030; 0031; 0032-0038
(2017/10/20)
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- METHOD FOR PRODUCING CARBOXYLIC ANHYDRIDE AND ARYLBORONIC ACID COMPOUND
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When phthalic acid is heated in heptane under azeotropic reflux conditions in the presence of a catalytic amount of an arylboronic acid compound (such as 2,6-(diisopropylaminomethyl)phenylboronic acid or 2,6-bis(diisopropylaminomethyl)phenylboronic acid), phthalic anhydride is obtained in high yield.
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Page/Page column 10-11
(2012/01/13)
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- Bronsted base-assisted boronic acid catalysis for the dehydrative intramolecular condensation of dicarboxylic acids
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Bronsted base-assisted boronic acid catalysis for the dehydrative self-condensation of carboxylic acids is described. Arylboronic acid bearing bulky (N,N-dialkylamino)methyl groups at the 2,6-positions can catalyze the intramolecular dehydrative condensation of di-and tetracarboxylic acids. This is the first successful method for the catalytic dehydrative self-condensation of carboxylic acids.(Figure Presented)
- Sakakura, Akira,Ohkubo, Takuro,Yamashita, Risa,Akakura, Matsujiro,Ishihara, Kazuaki
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supporting information; experimental part
p. 892 - 895
(2011/05/02)
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- PROCESS FOR MAKING 2,2-BIS (3,4-DICARBOXYPHENYL) HEXAFLUOROPROPANE
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There is provided a continuous process for making 2,2-bis(3,4-dicarboxyphenyl)hexafluoropropane. The process has the following steps: a) continuously feeding 2,2-bis(3,4-dimethylphenyl)hexafluoropropane and aqueous nitric acid into a reactor cell and b) heating the mixture to a temperature sufficient to effect reaction between the 2,2-bis(3,4-dimethylphenyl)hexafluoropropane and the nitric acid.
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Page/Page column 2-3
(2009/07/03)
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- Functionalized Photoreactive Compounds
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The present invention concerns functionalized photoreactive compounds of formula (I), that are particularly useful in materials for the alignment of liquid crystals. Due to the adjunction of an electron withdrawing group to specific molecular systems bearing an unsaturation directly attached to two unsaturated ring systems, exceptionally high photosensitivities, excellent alignment properties as well as good mechanical robustness could be achieved in materials comprising said functionalized photoreactive compounds of the invention.
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- Compounds, polymers, resin compositions and nonlinear optical devices
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The present invention provides, as heteroaromatic compounds made functional so as to be used for nonlinear optical materials, compounds represented by the following general formula (1), and also provides polymers obtained from these and nonlinear optical parts comprising such polymers. In the formula, Ar1 and Ar2 each represents a divalent aromatic group; R1, R2 and R3 each represents an atom or a group independently selected from a hydrogen atom or an alkyl group and an aromatic group; X1 represents a monovalent organic group; n represents an integer of 2 to 12; and Z1 and Z2 each represents a group independently selected from electron attractive functional groups.
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- Diamines and photosensitive polyimides made therefrom
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Disclosed is an aromatic diamine having the general formula where A is a group containing at least one aromatic ring, each Y is independently selected from or -OR, R is a group containing at least one olefinically unsaturated group, R' is hydrogen, alkyl to C25, aryl, or R, n is 1 to 4, and the number of olefinic groups in Y is at least 3 when each Y is and otherwise is at least 2. Photosensitive polyamic acids and polyimides can be prepared from the aromatic diamines which can be crosslinked with light to a mask to form patterns on a substrate.
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