METHOD FOR DETERMINING THE CONCENTRATION OF GRAFTED AMINO GROUPS ON THE SURFACE OF MINERAL FILLERS Russian patent published in 2021 - IPC G01N31/16 

FIELD: analytical chemistry.

SUBSTANCE: invention relates to analytical chemistry, namely to the determination of the concentration of grafted amino groups on the surface of mineral fillers, which can be used in the production of composite materials, modified mineral fillers and various sorbents based on them. The method for determining the concentration of grafted amino groups on the surface of mineral fillers includes preparing an acylating solution, adding it to a sample of a modified mineral filler, holding for a quantitative reaction, centrifuging the resulting mixture to separate the precipitate, titration with an alkali solution in the presence of an indicator, calculating the concentration of amino groups from the difference in the results of blank titration and titration of the sample, in this case, a 0.5 M solution of pyromellitic dianhydride in a mixed solvent of dimethylsulfoxide - pyridine is used as an acylating solution, the ratio of the sample weight to the volume of the acetylating solution is 1:5-1:12.5, the resulting mixture is kept in a water bath for at least 5 minutes at 95°С, after which water is added for hydrolysis and heated.

EFFECT: simplification of the method for determining the concentration of grafted amino groups.

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