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1、物理化学学报(Wuli Huaxue Xuebao)Acta Phys. 鄄Chim. Sin., 2008, 24(6)： 987-991Received: January 4, 2008; Revised: February 22, 2008; Published on Web: April 10, 2008. English edition available online at 鄢Corresponding author. Email: anwar_jmiyahoo.co.in; Tel: +9111鄄26981717 Extn. 3257; Fax: +9111鄄26980229鬁
2、Editorial office of Acta Physico鄄Chimica SinicaAJuneInteractions of Proline in Non鄄aqueous Anionic, Cationic and Nonionic Surfactants at Different TemperaturesALI Anwar鄢SHAHJAHAN (Department of Chemistry, Jamia Millia Islamia (Central University), New Delhi鄄110 025, India)Abstract： Density and visco
3、sity data of proline (Pro) in sodium dodecyl sulfate/cetyltrimethylammonium bromide/ poly (oxyethylene) isooctyl phenyl ether in formamide were measured at 298.15, 303.15, 308.15, and 313.15 K and 0.1 MPa. The density data were utilized to evaluate standard partial molar volumes (准0v) and partial mo
4、lar isobaric expansibility (准0E). The viscosity data were used to evaluate A鄄 and B鄄coefficients, free energy of activation of viscous flow (驻滋0鄢1) and (驻滋0鄢 2), per mole of solvent and solute respectively, enthalpy (驻H鄢) and entropy (驻S鄢) of activation of viscous flow. The results obtained were uti
5、lized in the qualitative elucidation of the Pro-surfactant/formamide and Pro- Pro interactions in the present systems.Key Words： Partial molar volume;Viscosity coefficient;InteractionSurfactant-protein interactions have been under investigation1-7 due to various applications of surfactants and the r
6、ole of protein in the very existence of life. Surfactants are widely used in phar- maceutical8,9, biological, and technological fields10-12. It has been found that commercial cleaners for lubrication and grease stripping applications normally contain halogenated sol- vents in their formulations. Gen
7、erally halogenated substances are toxic and pose a threat to biosphere. So, it is required to de- velop non鄄toxic, biodegradable, inexpensive, and environmen- tal鄄friendly formulations. The blending of water with polar or- ganic solvents along with common surfactants may prove to be an effective for
8、mulation for various cleaning operations13, or for doing sol鄄gel processes. The surfactants utilized in areas such as lubrication require water鄄free or water poor environment. Therefore, surfactant ag- gregation process in non鄄aqueous media has acquired consider- able interest in recent years. Polar
9、 solvents with properties re- sembling those of water, such as ethylene glycol, glycerol, and formamide, have been employed14-16. Studies reveal that a liquid capable of replacing water should be of high polarity to make it immiscible with oils and to make it a good solvent for the hydrophilic part
10、of surfactant molecules. Further, hydrogen bonding plays an important role in solvation of both ionic and nonionic surfactants and in the hydrogen bond- ed network in the liquid itself13. Literature survey reveals that the study of proteins in non鄄 aqueous surfactant media is rare17-19. So, in the p
11、resent investi- gation,wehavetakenaminoacid,proline(Pro)inpresenceofthree surfactants, sodium dodecyl sulfate (SDS), cetyltrimethylammo-nium bromide (CTAB), poly (oxyethylene) isooctyl phenyl ether (TX鄄100), and polar solvent, formamide (FA). Since proteins have complex structural organization and t
12、heir direct study is somewhat difficult, simpler units of proteins, i.e., amino acids (AA) are employed. The surfactants used belong to three broad classes, i.e., anionic, cationic, and nonionic. The different class- es of surfactants were used to have complete understanding of the effect of the nat
13、ure of surfactants on proline in non鄄aqueous media. To the best of our knowledge, no data has been reported on thermodynamic and transport study of amino acids in non鄄aque- ous surfactant media so far. Therefore, we have measured densi- ties and viscosities of solutions to evaluate various parameter
14、s of interest. These parameters are used to study the interactions pre- vailing in proline+non鄄aqueous surfactant systems.1Experimental Biochemical reagent grade proline (Thomas Baker, India, mass fraction跃0.99), analyticalreagentgrade SDS(s.d. fine. Chem. Ltd. , India, mass fraction 0.99) and CTAB(
15、E. Merck, Germany, mass fraction 0.995) were used after recrystallization from ethanol鄄water mixtures and drying in vacuum over P2O5at room temperature for at least 72 h. Analytical reagent grade TX鄄100 (BDH Chem. Ltd., Poole, England, mass fraction 0.995) was kept over molecular sieves (0.4 nm, Sig
16、ma Union Carbide type) to reduce the water content, if there was any. Spectroscopic grade FA (s.d. fine. Chem. Ltd., India) was purified as described in the literature20. The solutions of 0.01 mol L-1SDS+FA/CTAB+FA/TX鄄100+FA987Acta Phys. 鄄Chim. Sin., 2008Vol.24were used as solvents for preparation of 0.02, 0.04, 0.06, 0.08, and 0.10 mol L-1Pro solutions. Solutions were prepared by weight on Precisa XB鄄220 (Swiss鄄make) electronic
