Titrimetric behaviour of picric acid in mixed 2-methoxyethanol/water solvent system

The titrimetric behaviour of picric acid in pure 2-methoxyethanol, in pure water and in many of their binary mixtures has been investigated by using the conductometric method and 1,1,3,3-tetramethylguanidine as titrant base. The study has been carried out working at 0, 25, 50 and 75-degrees-C and the effects of temperature and composition of the solvent mixture on the shape of the curves and on the accuracy of the analytical recovery have been pointed out. Previous observations on the hypothetical existence of a particular ''limiting mixture'' which separates the solvent system under study into two groups (0 less-than-or-equal-to X(water) < ''limiting mixture' and ''limiting mixture'' < X(water) less-than-or-equal-to 1, where X represents the mole fraction) have been confirmed and a stoichiometric composition for such a mixture, which depends on temperature, has been suggested.