9 января, 2016 
Pokraskin The analysis of mixtures of these two acids is very simple. The mixture is first titrated with nitrite to determine the total of the two acids, and then the 2,5,7 acid is titrated with sodium hypobromite. The 2,5,7 add reacts smoothly in hydrochloric acid solution with sodium hypobromite, taking up two atoms of bromine, while the 2,6,8 acid is entirely unreactive. This behavior is surprisingly similar to that of Schaeffer salt and R salt.
To carry out the second titration, a measured amount of the sulfonic acid sample is dissolved in 300 parts of water, and 20 cc. concentrated hydrochloric acid is added for each 2 grams of the sulfonic
acid. The temperature is lowered to 0°C. by addition of ice, and the the solution is titrated with 0.2 N NaOBr solution to a definite blue coloration with starch-iodide paper. The 0.2 N hypobromite solution is prepared in the following way:
To a solution of 14 grams of pure NaOH in 500 cc. water containing about 200 grams of pure ice is added, with thorough stirring, 16 grams of bromine. The solution is diluted to 1 liter and standardized by known methods (e. g., with arsenious acid).
A dilute solution of the pure 2,6,8 acid containing hydrochloric acid gives an immediate test for free bromine with only one drop of the hypobromite solution.
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