METHOD OF DETERMINING CONCENTRATION OF GRAFTED AMINO GROUPS ON SURFACE OF MINERAL FILLERS Russian patent published in 2015 - IPC G01N31/16 G01N21/78 

FIELD: chemistry.

SUBSTANCE: method of determining concentration of grafted amino groups on the surface of mineral filling agents includes preparation of acetylating solution by mixing initial components, its addition to weighed portion of modified mineral filler sample, exposure for quantitative realisation of reaction, titration with alkali solution in presence of indicator, calculation of concentration of amino groups by difference of results of idle titration and sample titration. As acetylating solution used is 0.5-0.6 M solution of acetic anhydride in mixed solvent dichloroethane-pyridine in ratio from 0.5:1-2:1, which contains 0.025-0.15 mol/l of chloric acid as catalyst. 0.5-0.6 M of acetylating solution in mixed solvent, containing chloric acid, is added to weighed portion of modified mineral filler, ratio of weighed portion of sample weight to volume of acetylating solution constitutes 1:4-1:5, after which it is exposed and hydrolysing mixture, consisting of dimethylformamide, pyridine, water, taken in ratio 6:3:1 respectively, is added. After that, obtained mixture is centrifuged to separate residue.

EFFECT: simplification and extension of assortment of analysed materials, containing grafted amino groups on the surface of mineral fillers.

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