METHOD FOR PREPARING POLY-1,3,4-OXADIAZOLE Russian patent published in 2005 - IPC

FIELD: organic chemistry, chemical technology.

SUBSTANCE: invention relates to a method for preparing poly-1,3,4-oxadiazole that can be used in the development of highly thermostable, chemostable and highly strength materials - fibers, films, membranes. Method involves the polycondensation reaction of dicarboxylic acid with hydrazine derivative or with dicarboxylic acid dihydrazide at temperature 190-220°C that is carried out in solvent medium for 3-7 h in the presence of triphenyl phosphite. As a solvent method uses ionic liquid of the following general formula: wherein R₁ means C_nH_2n+1 wherein n = 1-7; iso-C₃H₇; Si(CH₃)₃; R₂ means C_nH_2n+1 wherein n = 2-7; iso-C₃H₇; Si(CH₃)₃; R means Me (CH₃); H; Y means Cl, Br, PF₆, BF₄. Invention provides preparing polymers with quantitative yield and molecular mass 60000-450000 Da and to enhance ecological safety and to improve technological effectiveness of a single-step process and without hydrolysis of the synthesized polymer.

EFFECT: improved preparing method.

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