THE EFFECT OF UREA ON METHYLENE BLUE, ITS SELF-ASSOCIATION, AND INTERACTION WITH POLYELECTROLYTES IN AQUEOUS SOLUTION

✍ Scribed by Mukerjee, Pasupati; Ghosh, Ashish K.

• Book ID: 120475986
• Publisher: American Chemical Society
• Year: 1963
• Tongue: English
• Weight: 512 KB
• Volume: 67
• Category: Article
• ISSN: 0022-3654
• DOI: 10.1021/j100795a047

✦ Synopsis

The effect of urea on the association of methylene blue in water, the extractability of methylene blue perchlorate into chloroform and its solubility, and the metachromatic interaction of methylene blue with polyacrylic acid have been investigated. Urea decreases the self-association of methylene blue and ita metachromatic interactions very efficiently, and strongly influences the activity coefficient of monomeric methylene blue. These facts have been interpreted in terms of water-structure promotion around the dye ions and the consequent hydrophobic bonding in dye-association and metachromatic interactions. Several other lines of reasoning support the important role of water-structure effects in dye-association. The quantitatively smaller effect of urea on aliphatic systems as compared to aromatic systems has been interpreted in terms of the possible chain-entropy contribution for the former in hydrophobic bonding.