341-58-2Relevant articles and documents
Homocoupling of a Grignard Reagent toward the Synthesis of 2,2′-Bis(trifluoromethyl)-4,4′-diaminobiphenyl
Nakatani, Jiro,Nozoe, Tatsuhiro
supporting information, p. 2442 - 2446 (2021/11/13)
A new process for the synthesis of 2,2′-bis(trifluoromethyl)-4,4′-diaminobiphenyl (TFMB) comprising three steps has been industrially developed. The first step is the homocoupling of the Grignard reagent derived from 1-chloro-2-(trifluoromethyl)benzene with iron chloride(III) in the presence of an oxidizing agent to afford 2,2′-bis(trifluoromethyl)biphenyl. The second step is the nitration of this biphenyl to 2,2′-bis(trifluoromethyl)-4,4′-dinitrobiphenyl, and the third step is the reduction of this dinitrobiphenyl using hydrogen over Pd/C to afford TFMB. This process has been demonstrated on an industrial scale.
Preparation method of 2,2'-bis (trifluoromethyl)-4,4'-diaminobiphenyl
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Paragraph 0027; 0031-0033; 0037-0039; 0043-0045; 0049; ..., (2021/06/26)
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.
Method for preparing polyimide monomer having low yellow index
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Paragraph 0039; 0050-0051, (2021/11/02)
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.