Nuclear magnetic resonance studies of microemulsions and related systems: 2-butoxyethanol in water

Abstract

The "C chemical shift, T I , and 'H TI data for 2-butoxyethanol (BE) in DzO as a function of concentration are presented. The nmr parameters are consistent with thermodynamic data for the samc system in that it appears that 2-butoxycthanol in water undergoes a pseudo phase transition at about 1.2 M. The chemical shift for each carbon is different in the microphase relative to either aqueous solutior~ or pure BE. The shift differences are due to a combination of factors, conformer population changes, changes in the polarity of the oxygen, and a solvent effect on chemical shift. The more organic the medium, the higher the population of trons relative to gauche conformers. The motion of BE is more restricted in the microphase than in either dilute aqueous solution or in the pure liquid. The number of adsorbed D,O molecules pcr molecule of BE is less in the microphase than in aqueous solution.0 . DESROSIERS, T. VAN DINTER et J. K. SAUNDERS. Can. J. Chcm. 62, 56 (1984).On rapporte des dkplacements chimiques du I3C et des donnkes de TI et %I TI relatives au butoxy-2 Cthanol (BE) dans le D1O en fonction de la concentration. Les paramktres de la rmn s'accordent avec les donnkes thermodynamiques d e ce systtme dans lequel il semble que le butoxy-2 ethanol dans I'eau subit une pscudotransition de phase a environ I ,2 M. Le dkplacement chimique de chaque carbone est diffkrent dans la microphase par rapport la solution aqueuse dc BE ou par rapport au BE pur. Lcs diffkrences de dkplacement chimique sont provoqukes par une combinaison de facteurs: variation de la population du conformkre, variation de la polaritk de I'oxygkne et I'cffet du solvant sur le dkplacement chimiquc. Plus Ic milieu est organique plus la population de conformtre trans sera Clevke par rapport a celle du conformtre gauche. Le mouvement du BE est plus restreint dans la microphase que dans la solution aqueuse diluke ou dans le liquide pur. Le nombre de molkcules dc D1O absorbkes par molkcule de BE est plus faible dans la microphase que dans la solution aqueuse.[Traduit par le journal]The high solubilizing capacity of microemulsions (I), in particular in their application in tertiary oil recovery processes (2), has prompted extensive studies of their physicochemical properties (3, 4). Of particular interest is the role of the cosurfactant (5) and detection of microphase transitions if they occur. Nuclear magnetic resonance (nmr) can be of considerable value in these studies as the local environment of the various components can be ascertained from chemical shift data and the molecular dynamics can be determined from relaxation times (4) and pulsed gradient spin echo measurements (6).As part of an nmr study of microemulsions we have examined the chemical shift (6) and relaxation time (TI) data of the system 2-butoxyethanol (BE) in D,O. The study is restricted to the water-rich region. This system was chosen because BE has interesting properties as a cosurfactant (7) in microemulsions and thermodynamic data (8) have shown that it undergoes a microphase trans...

Thermodynamics of Mixed Micellization of Isomeric Hexanediols in Sodium Dodecyl Sulfate

“…[1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17] Alcohols are known to play important roles as cosurfactants in a number of industrial and research applications including the addition of alcohol to surfactant and oil systems in order to form microemulsions. [1,[18][19][20][21][22][23][24] Microemulsions are added to oil reservoirs to enhance recovery by mobilizing some of the residual oil that remains after extraction. Typical cosurfactants used in microemulsion formation are n-alcohols such as 1-propanol, 1-butanol, and 1-pentanol.…”