METHOD OF OBTAINING POLYBENZIMIDAZOLS BASED ON 4,4'-DIPHENILPHTHALIDEDICARBONIC ACID Russian patent published in 2008 - IPC C08G73/18 C08J5/18 B01D71/62 

FIELD: chemistry.

SUBSTANCE: invention relates to method of obtaining polybenzimidazols based on 4,4^'-diphenilphthalidedicarbonic acid, used as proton-conducting polymeric membranes which are used in hard-polymeric fuel elements. Method of obtaining polybenzimidazols is the following: reaction of polycondensation of 4,4^'-diphenilphthalidedicarbonic acid and aromatic tetraamin is carried out at heating in medium of Iton reagent with step-by-step rise of temperature from 80 to 150°C. In the process of synthesis phosphorus pentaoxide is added in amount from 1 to 2 mols on a mol of monomers. The invention allows to improve ecological safety of the process, reduce its power-consuming, and obtain during one stage with quantitative output high-molecular soluble in organic solvents film-forming polymer with molecular weight 40000-100000, capable of reactions of structuring.

EFFECT: improvement of ecological safety of the process of polybenzimidazols obtaining with reduction of process power-consuming and increase of product output.

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