COLL 150 |
| Li Li, State Key Laboratory for Heavy Oil Processing, University of Petroleum, China, No 271, Bei'er Road, Dongying, 257061, China, Xiaoyi Zhang, Department of Chemistry, Guizhou Normal University, Guizhou Normal University ,China, Guiyang, 550001, China, and Zifeng Yan, Department of Chemical Engineering, University of Petroleum, Dongying, Shandong, 257061, China. |
| The cloud point (CP) of aqueous solutions of polyoxyethylated nonionic surfactants (NS) has theoretical and practical importance. Due to their low critical micelle concentrations and high micellar molecular weights, NS in solution at use levels of a few percent exist mainly as micelles, which resemble cross-linked polymer molecules. In this work, the cloud point (CP) values of twenty nonionic surfactants with oxyethylene groups as the hydrophilic group have been subjected to a quantitative structure-property relationship (QSPR) study. Molecular descriptors derived from the quantum chemistry have been used for the studies. These descriptors include the total electronic energy (ET), the energy of the highest occupied molecular orbital (EHOMO), the energy of the lowest unoccupied molecular orbital (ELUMO), the molecular polarizability (¦Ì), the net charges of the oxyethylene groups (Q(EO)n)and the oxygen on the oxyethylene groups (QO(H)), which are calculated with tow quantum chemical methods. The regressed model has been established with the multiple linear regression method. The relevant coefficient of multiple determinations was produced: r2=0.951. The model can be used to predict the cloud point of nonionic surfactants. The results showed that the influence of the net charges on the cloud point is very complicated and the interaction between surfactants and solvent molecules include electrostatic interaction, the hydrogen bond and dipolar interaction. |
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Symposium in Memory of Arthur W. Adamson
2:00 PM-5:40 PM, Monday, March 29, 2004 Marriott -- Orange County 4, Oral
Division of Colloid and Surface Chemistry |