METHOD OF DETERMINING MASS PORTION OF MAJOR SUBSTANCE OF ALKYLPHOSPHONIC ACID DIALKYL ESTERS Russian patent published in 2008 - IPC G01N31/16 

FIELD: analytical methods.

SUBSTANCE: invention relates to analysis of non-biological materials with chemical methods via hydrolysis followed by titration in presence of chemical indicators. Method consists in analysis of aqueous solutions of these materials wherein 0.10-0.12 g sample is treated with 4 mL of concentrated 47.6% hydrobromic acid solution, reaction mixture is evaporated to residual volume 0.3-0.5 mL of test solution, neutralized with 1 N sodium hydroxide solution in presence of methyl red indicator until weakly rose coloration appears, after which it is titrated with 0.1 N sodium hydroxide solution until weakly red coloration is transformed into stramineous. Finally, thymolphtalein is added and solution is post-titrated until stable blue-green color. Mass portion of major substance is calculated in terms of following equation: M = [(V₁-V₂)*T*K/m]*100, where V₁ is volume of 0.1 N sodium hydroxide solution utilized for titration of the sample of alkylphosphonic acid dialkyl ester in presence of thymolphtalein, mL; V₂ is volume of 0.1 N sodium hydroxide solution utilized for titration of blank sample in presence of thymolphtalein, mL; T is titer of alkylphosphonic acid dialkyl ester equivalent to 1 mL of 0.1 N sodium hydroxide, g/mL; K is correction factor for concentration of sodium hydroxide solution (K=1 when standard titer is used); m is mass of the sample of alkylphosphonic acid dialkyl ester used for measurements, g.

EFFECT: simplified analytical procedure and increased accuracy of measurement.

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