Temperature-concentration oscillations of crystal-solution phase equilibria in the presence of trace impurities of surface-active agents

✍ Scribed by E. V. Kiryanova

• Publisher: John Wiley and Sons
• Year: 2011
• Tongue: English
• Weight: 204 KB
• Volume: 46
• Category: Article
• ISSN: 0232-1300
• DOI: 10.1002/crat.201000504

✦ Synopsis

Using the examples of aqueous salt solutions NaNO 3 , KNO 3 , RbNO 3 , K 2 SO 4 , NaBr . 2Н 2 О, KBr, and NН 4 NO 3 , it was experimentally proven that the new phenomena, i.e. temperature-concentration oscillations of crystal-solution phase equilibria detected previously in the range of 15-45 °С remain in the presence of trace impurities (10 -4 -10 -3 wt. %) of ion-active organic matters. The signs of breaks transformation into pair oscillations of "maximum-minimum" type are established for the K 2 SO 4 , NaBr, KBr solutions. The efficiency of influence of trace impurities on phase equilibria sharply rises in the areas of the temperature-concentration oscillations (the saturation temperature ranges up to 10 K). The impurity efficiency is promoted by the presence of the amides in its content (as compared with the sulphates) and an increase in length of the hydrocarbon radical. The phenomenon is absent in case of an addition of ion-inactive compounds.