- Preparation Method for 2,2'-Bis(Trifluoromethyl)-4,4'-Diaminobiphenyl
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The present invention relates to a method for producing 3,3 '- bis 2,2 - diaminobiphenyl by a benzidine rearrangement reaction from' -4 bis hydrazinobenzene in high yield, and more specifically, to dissolve 4 3,3 '-' - bis hydrazinobenzene in (A) organic solvent. (B) The solution prepared in (A) is added dropwise to an inorganic acid solution while maintaining a temperature below 0 °C.30°C. When the (C) titration is completed, less than 0 °C -30°C or less is reacted. 2,2 '- Bis -4, 4' - diaminobiphenyl, which is characterized in that it comprises.
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Paragraph 0024; 0025
(2021/07/20)
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- Preparation method of 2,2'-bis (trifluoromethyl)-4,4'-diaminobiphenyl
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The invention discloses a preparation method of 2,2'-bis (trifluoromethyl)-4,4'-diaminobiphenyl. The method comprises the following steps: S1, preparing 3,3'-bis (trifluoromethyl) diphenylhydrazine through catalytic reduction reaction by taking m-nitrobenzotrifluoride and hydrazine hydrate as raw materials and taking low-boiling-point alcohol as a solvent under the catalysis of inorganic base and palladium carbon at 40-76 DEG C; and S2, in a protective gas atmosphere, adding the 3,3'-bis (trifluoromethyl) diphenylhydrazine prepared in the step S1 into inorganic acid, and preparing 2,2'-bis (trifluoromethyl)-4,4'-diaminobiphenyl through a rearrangement reaction at a temperature of -10 DEG C to 20 DEG C. According to the invention, hydrazine hydrate is used as a reducing agent instead of hydrogen, the use amount of the hydrazine hydrate is small, the reaction condition is mild, the requirement on equipment is low, and the catalyst is small in use amount, reusable and low in cost.
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Paragraph 0027; 0029-0030; 0033; 0035-0036; 0039; ...
(2021/06/26)
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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 0039; 0050-0051
(2021/11/02)
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- Visible-light-promoted oxidative dehydrogenation of hydrazobenzenes and transfer hydrogenation of azobenzenes
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Azo compounds are widely used in the pharmaceutical and chemical industries. Here, we report the use of a non-metal photo-redox catalyst, Eosin Y, to synthesize azo compounds from hydrazine derivatives. The use of visible-light with air as the oxidant makes this process sustainable and practical. Moreover, the visible-light-driven, photo-redox-catalyzed transfer hydrogenation of azobenzenes is compatible with a series of hydrogen donors such as phenyl hydrazine and cyclic amines. Compared with traditional (thermal/transition-metal) methods, our process avoids the issue of over-reduction to aniline, which extends the applicability of photo-redox catalysis and confirms it as a useful tool for synthetic organic chemistry.
- Wang, Xianya,Wang, Xianjin,Xia, Chungu,Wu, Lipeng
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supporting information
p. 4189 - 4193
(2019/08/07)
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- Preparation method of 2,2'-bis(trifluoromethyl)-4,4'-diaminodiphenyl
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The invention relates to a preparation method of 2,2'-bis(trifluoromethyl)-4,4'-diaminodiphenyl. The preparation method comprises the following steps: synthesizing 3,3'-bis(trifluoromethyl)hydrazo-benzene in an inorganic alkaline aqueous solution by adopting nitrobenzotrifluoride as a raw material, adopting a phase transfer catalyst, a co-catalyst and Pd/C as a catalytic system and adopting aromatic hydrocarbon as a solvent, and performing the re-arrangement reaction on the 3,3'-bis(trifluoromethyl)hydrazo-benzene in an inorganic acid aqueous solution, thus obtaining 2,2'-bis(trifluoromethyl)-4,4'-diaminodiphenyl, wherein the phase transfer catalyst is one or a mixture of more of sodium dodecyl benzene sulfonate, sodium dodecyl sulfate and cetyl trimethyl ammonium bromide, and the co-catalyst is one or a mixture of more of 2,3-dichloro-1,4-naphthoquinone, 2-hydroxyanthraquinone and 2,6-dioxyanthraquinone. The preparation method has the advantages of mild reaction condition, simple process, high product quality and yield, low production cost, environmental friendliness, suitability for continuous production and the like.
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Paragraph 0029; 0030; 0032; 0033; 0035; 0036; 0038; 0039
(2019/02/04)
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- Process for Producing 2,2'-Bis(Trifluoromethyl)-4,4'-Diaminobiphenyl
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A process for producing 2,2′-bis (trifluoromethyl)-4,4′-diaminobiphenyl which is useful as a raw material for polyimide resin, etc. In benzidine rearrangement of 3,3′-bis(trifluoromethyl) hydrazobenzene in the presence of an inorganic acid such as sulfuric acid aqueous solution or concentrated hydrochloric acid, use of a water-immiscible organic solvent such as toluene as reaction solvent can increase the yield of the product. 3,3′-bis(trifluoromethyl) hydrazobenzene can be synthesized by reduction of m-nitrobenzotrifluoride.
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Page/Page column 2
(2009/04/24)
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- PROCESS FOR PRODUCING 2,2'-BIS(TRIFLUOROMETHYL)-4,4'-DIAMINOBIPHENYL
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A process for producing 2,2'-bis(trifluoromethyl)-4,4'-diaminobiphenyl, which is useful as a material for polyimide resins, etc. It comprises using a water-immiscible organic solvent, such as toluene, as a reaction solvent to conduct the benzidine rearrangement of 3,3'-bis(trifluoromethyl)hydrazobenzene in the presence of an inorganic acid such as an aqueous sulfuric acid solution or concentrated hydrochloric acid. Thus, the rearrangement yield is heightened. The 3,3'-bis(trifluoromethyl)hydrazobenzene can be synthesized by the reduction of m-nitrobenzotrifluoride.
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Page/Page column 5
(2008/06/13)
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- Ultrasonically activated reduction of substituted nitrobenzenes to corresponding N-arylhydroxylamines
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Arylhydroxylamines can be obtained by reduction of the corresponding nitroaromatic compounds. We report here an efficient preparation of arylhydroxylamines by a controlled reduction of nitro compounds using zinc metal and ammonium chloride under ultrasonic activation in very short reaction times.
- Ung, Stéphane,Falguières, Annie,Guy, Alain,Ferroud, Clotilde
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p. 5913 - 5917
(2007/10/03)
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- Pyridazinedione derivatives useful in treatment of neurological disorders
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The present invention relates to pyridazino[4,5-b]indoles, and pharmaceutically useful salts thereof, which are excitatory amino acid antagonists and which are useful when such antagonism is desired such as in the treatment of neurological disorders. The invention further provides pharmaceutical compositions containing pyridazino[4,5-b]indoles as active ingredient, and methods for the treatment of neurological disorders.
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