Phase behavior of nonionic surfactant/oil/water systems containing light alkanes

Journal Article · Mon Nov 01 04:00:00 EST 1993 · Langmuir; (United States)

DOI:https://doi.org/10.1021/la00035a035· OSTI ID:5677348

McFann, G J; Johnston, K P ^[1]

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1. Univ. of Texas, Austin, TX (United States)

The phase behavior of nonionic ethoxylate surfactant/light alkane/water systems is reported in detail. In compressible liquids such as propane, phase transitions which are normally induced by changing temperature or salinity can also be accomplished with pressure. A complete transition from a lower to middle to upper phase microemulsion with pressure is reported for the first time in propane. Widely accepted trends in surfactant phase behavior as a function of the alkane carbon number (ACN) of the oil component reverse themselves in the light alkanes butane, propane, and ethane. This pattern occurs in both reverse micelle systems (small water-to-oil ratio) and Winsor microemulsion systems (water-to-oil ratio near unity). The observed pressure and ACN effects can be explained qualitatively in terms of the miscibility gaps of the binary phase diagrams and quantitatively in terms of enthalpic and entropic interactions between the surfactant tails and the compressible solvent. 69 refs., 9 figs.

• OSTI ID: 5677348
• Journal Information: Langmuir; (United States), Journal Name: Langmuir; (United States) Vol. 9:11; ISSN LANGD5; ISSN 0743-7463
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360606 -- Other Materials-- Physical Properties-- (1992-)
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical & Physicochemical Properties
ALKANES
COLLOIDS
DISPERSIONS
EMULSIONS
ENTHALPY
ENTROPY
HYDROCARBONS
HYDROGEN COMPOUNDS
MICELLAR SYSTEMS
MICROEMULSIONS
MIXTURES
OILS
ORGANIC COMPOUNDS
OTHER ORGANIC COMPOUNDS
OXYGEN COMPOUNDS
PHASE STUDIES
PHYSICAL PROPERTIES
PRESSURE DEPENDENCE
SURFACTANTS
THERMODYNAMIC PROPERTIES
WATER