78906-84-0Relevant articles and documents
Relationship of Structure to Properties of Surfactants. 12. Synthesis and Surface Properties of Long-Chain 2-Pyridinium Alkanoates
Zhao, Fulin,Rosen, Milton J.
, p. 6041 - 6043 (2007/10/02)
Three surface-active 2-pyridinium alkanoates, 2-pyridinium dodecanoate, tetradecanoate, and hexadecanoate, have been synthesized and characterized.Their physical properties investigated include decomposition and Krafft points, pKa of the conjugate acids, and ultraviolet absorption.From surface tension measurements on aqueous solutions of the compounds at 25 deg C, critical micelle concentrations (cmc), surface excess concentrations, minimum area per molecule at the aqueous solution/air interface, efficiency and effectiveness of surface tension reduction, and standard free energies of adsorption (ΔG0ad) and of micellization (ΔG0mic) have been calculated.The cmc of a 2-pyridinium alkanoate is considerably smaller than that of the corresponding 2-trimethylammonium alkanoate, which may be due to the ease of packing of the planar pyridinium and carboxylate groups.At the aqueous solution/air interface, the molecules are almost close packed, with orientation perpendicular to the interface and both pyridinium and carboxylate groups in the aqueous phase.The ΔG0ad per methylene group is -3.15 kJ; the ΔG0mic per methylene group, -2.7 kJ, at 25 deg C.
