- Method for preparing biphenyldianhydride isomer by ultrasonic-assisted catalytic coupling
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The invention discloses a method for preparing biphenyldianhydride isomers through ultrasonic-assisted catalytic coupling. The main contents include a mixture of a nickel salt catalyst and zinc as a reducing agent, 2-THF used as a solvent, an aryl (or methyl) N - chloronaphthalimide and -4 - propyl (or isopropyl) N - chlorodifluoroimide, under -3 - by means of an ultrasonic-assisted catalytic coupling reaction 60 - 100 °C 0.5 - 3 hours. The separation and purification of the three biphenyltetracarboxylic acid isomers are realized by using different solubility parameters, and the biphenyldianhydride isomer pure product is finally obtained. The invention is characterized in that a simple method for separating the three biphenyltetracarboxylic acid isomers is established, the problem of difficulty in separation of the three biphenyl dianhydride mixtures is solved, and 3,4 - biphenyl dianhydride ’ with an asymmetric structure is obtained at lower cost.
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Paragraph 0028-0030
(2021/11/06)
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- Method for preparing biphenyldianhydride through microwave-assisted catalytic coupling
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The invention discloses a method for preparing biphenyldianhydride through microwave-assisted catalytic coupling. In a green solvent 2 - methyltetrahydrofuran (2-THF) system, under microwave irradiation, under microwave irradiation, under a temperature 60 - 95 °C condition, the reaction time is over 20-60 minutes to prepare a biphenyl derivative, and after hydrolysis and dehydration, biphenyldianhydride is obtained. The present invention is characterized in that an organometallic complex is formed by using a halogenated monomer having a complexing action, and zinc halide generated by the reaction with the reaction. It is avoided that its deposition on the reducing agent metal surface results in a reduction in its reducing ability. Compared with the traditional method for preparing the same biphenyl dianhydride, the method is high in reaction speed, the reducing agent is close to the quantitative reaction, and the cost is lower.
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Paragraph 0027; 0029; 0033; 0035-0036; 0038
(2021/11/06)
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- Preparation and separation method of biphenyldianhydride isomer
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The method mainly comprises the following steps: taking nickel salt as a catalyst, coupling with zinc as a reducing agent, coupling with an aliphatic 3 - chloronaphthalimide and an aryl 4 - chlorosuccinimide mixture as a raw material to generate a biphenyl dianhydride derivative, and separating by using different solubility parameters and obtaining 3 and 4 ’ - respectively. 3,3 ’ - And 4, 4 ’ - biphenyl derivatives are hydrolyzed and dehydrated to obtain three biphenyldianhydride isomers, and the patent application is characterized in that a simple method for separating the three biphenyltetracarboxylic dianhydride intermediate is established.
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Paragraph 0024; 0027
(2021/10/05)
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- Synthesis method for 3,3',4,4'-biphenyltetracarboxylic acid
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The invention discloses a synthesis method for 3,3',4,4'-biphenyltetracarboxylic acid. The synthesis method comprises the following steps: with 4,4'-dimethyl biphenyl as a starting raw material, subjecting the 4,4'-dimethyl biphenyl and cyclic anhydride as shown in a formula I which is described in the specification to a Friedel-Crafts acylation reaction so as to obtain an intermediate II, and carrying out an oxidation reaction so as to obtain the 3,3',4,4'-biphenyltetracarboxylic acid, wherein the cyclic anhydride as shown in the formula I is selected from the group consisting of succinic anhydride, glutaric anhydride, adipic anhydride and maleic anhydride. The method provided by the invention does not need an expensive catalytic system, so the production cost of synthesizing the 3,3',4,4'-biphenyltetracarboxylic acid is greatly reduced; the method provided by the invention is simple to operate, mild in reaction conditions, less in three wastes, easy in wastewater treatment and friendly to the environment; and the raw material, namely the 4,4'-dimethyl biphenyl adopted in the method provided by the invention is a byproduct of a medical intermediate, namely sartan biphenyl, and theproduction amount of the byproduct accounts for about 10% of the production amount of the sartan biphenyl, so the waste can be turned into treasure after the byproduct is applied to synthesis of the3,3',4,4'-biphenyltetracarboxylic acid.
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- Preparation method of 3, 3', 4, 4'-biphenyltetracarboxylic dianhydride
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The invention discloses a preparation method of 3, 3', 4, 4'-biphenyltetracarboxylic dianhydride. The method includes the reactions of: (1) chlorination reaction: taking phthalic anhydride as the rawmaterial, adding a mixed solution of sodium hypochlorite aqueous solution and sodium hydroxide aqueous solution dropwise, carrying out chlorination reaction, and adjusting the pH value to generate 4-chlorophthalic acid monosodium salt; (2) coupling and hydrolysis: carrying out coupling reaction and hydrolysis reaction on the 4-chlorophthalic acid monosodium salt in the presence of a catalyst and acocatalyst under an alkaline condition to generate 3, 3', 4, 4'-biphenyltetracarboxylic acid sodium salt, wherein the catalyst is a palladium-carbon catalyst or a nickel-palladium-carbon catalyst, and the cocatalyst is hydroxylamine sulfate or hydroxylamine hydrochloride; and (3) acidification into 3, 3', 4, 4'-biphenyltetracarboxylic acid, and then drying and dehydration, thus obtaining 3, 3', 4, 4'-biphenyltetracarboxylic dianhydride. The method provided by the invention adopts phthalic anhydride as the raw material for reaction with sodium hypochlorite to synthesize 3, 3', 4, 4'-biphenyltetracarboxylic dianhydride, is low in production cost, avoids the use of potassium permanganate oxidation, simplifies the production process, and has small pollution, and high yield.
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- Synthesis method of 3,3',4,4'-biphenyltetracarboxylic anhydride
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The invention discloses a synthesis method of 3,3',4,4'-biphenyltetracarboxylic anhydride, and belongs to the field of chemical synthesis. The synthesis method comprises the following steps: adding 4-bromo-o-xylene into magnesium powder and iodine (simple substance) to obtain a reactant; heating the reactant and 4-chloro-o-xylene to carry out reactions in the presence of nickel acetylacetone taken as the catalyst to obtain 3,3',4,4'-tetramethyl diphenyl, oxidizing and acidifying 3,3',4,4'-tetramethyl diphenyl to obtain 3,3',4,4'-biphenyltetracarboxylic acid, and finally carrying out high temperature dehydration to obtain 3,3',4,4'-biphenyltetracarboxylic anhydride.
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Paragraph 0004; 0005; 0006; 0007
(2017/05/19)
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- 3,4-DIALKYLBIPHENYLDICARBOXYLIC ACID COMPOUND, 3,4-DICARBOALKOXYBIPHENYL-3', 4'-DICARBOXYLIC ACID AND CORRESPONDING ACID ANHYDRIDES, AND PROCESSES FOR PRODUCING THESE COMPOUNDS
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The present invention relates to the 3,4-Dicarboalkoxybiphenyl-3′,4′-dicarboxylic acid (including the corresponding acid anhydride) represented by the general formula (1): wherein R11 and R12 each represents an alkyl group having 1 to 4 carbon atoms, and n represents the number of waters of hydration that is 0 or 1.
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- Process for manufacture of 3,3',4,4'-biphenyltetracarboxylic acid
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A process for the preparation of 3,3',4,4'-biphenyltetracarboxylic acid salt by the dehalodimerization of a 4-halophthalic acid salt. The process uses hydroxylamine or one of its salts as the reducing agent in an alkaline solution, preferably of pH 10 or above, and palladium catalyst. The reaction is carried out between 50° and 150° C.
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- Process for producing highly pure 3,3',4,4'-biphenyltetracarboxylic acid or dianhydride thereof
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Highly pure 3,3',4,4'-biphenyltetracarboxylic acid (BPTA) and dianhydride thereof (BPDA) are produced by heating crude BPTA to give BPDA, treating the BPDA with hot water to give highly pure BPTA, and in the case of highly pure BPDA, heat treating the pure BPTA to give highly pure BPDA.
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- Process for preparation of 3,3',4,4'-biphenyltetracarboxylic acid salts
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When a 4-halogenoorthophthalic acid salt is dissolved together with a base in an alkaline aqueous solution and the solution is heated in the presence of a catalyst comprising a noble metal supported on a carrier, a formic acid salt and a small amount of an aliphatic compound containing a hydroxyl group, a 3,3',4,4'-biphenyltetracarboxylic acid salt is obtained in a high yield.
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- Process for producing biphenyltetracarboxylic dianhydrides
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A process for separating and purifying biphenyltetracarboxylic dianhdride isomers from a mixture of these isomers by fractional crystallization in aliphatic acid anhydrides or acetone. The isomeric mixture is obtained by heating biphenyltetracarboxylic acids, optionally in the presence of an aliphatic acid anhydride. The biphenyltetracarboxylic acids are obtained by oxidizing coupling dimers of o-xylene or by hydrolyzing coupling dimers of dimethyl phthalate.
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