Why micelles form in water and hydrazine. A reexamination of the origins of hydrophobicity

Journal Article · Thu Oct 27 04:00:00 EDT 1983 · J. Phys. Chem.; (United States)

DOI:https://doi.org/10.1021/j100245a040· OSTI ID:6981161

Ramadan, M S ^[1]; Evans, D F; Lumry, R

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1. Alexandria Univ., Egypt

Micelle formation, a typical ''hydrophobic process'' in water, has been studied in hydrazine. The standard free energies, ..delta..G, for micellization are similar in the two solvents (-9.6 kcal mol/sup -1/ for water and -7.8 kcal mol/sup -1/ for hydrazine for sodium dodecyl sulfate). The corresponding ..delta..H/sup 0/ values (-6.1 and -13.3 kcal mol/sup -1/, respectively) and ..delta..S values (11 and -18 gibbs mol/sup -1/, respectively) are very different. The differences between hydrazine and water are attributed to a large positive increment in both ..delta..H(H/sub 2/O) and ..delta..S(H/sub 2/O) accompanying the transfer of the surfactant hydrocarbon chain out of water. These increments nearly compensate each other and thus make only a small contribution to the free energy in the temperature range 25-45/sup 0/C. This interpretation is bolstered by the almost identical free energy of transfer of a methylene group from water (-0.76 kcal mol/sup -1/) and hydrazine (-0.71 kcal mol/sup -1/) to the micelle. These results suggest that the lipophobic properties of water and hydrazine are very similar and that the unique properties of water do not play a dominant role in the equilibrium properties of this liquid. The critical micelle concentrations (cmc) are reported for sodium, octyl, decyl, and dodecyl sulfates and decyl- and dodecyltrimethylammonium bromide in hydrazine at 25, 35, and 45/sup 0/C. 3 figure, 5 tables.

• OSTI ID: 6981161
• Journal Information: J. Phys. Chem.; (United States), Journal Name: J. Phys. Chem.; (United States) Vol. 87:22; ISSN JPCHA
• Country of Publication: United States
• Language: English

Related Subjects

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10 SYNTHETIC FUELS
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201 -- Chemical & Physicochemical Properties
ALKALI METAL COMPLEXES
ALKALI METAL COMPOUNDS
AMMONIUM COMPLEXES
AROMATICS
BROMIDES
BROMINE COMPOUNDS
CHEMICAL ANALYSIS
CHLORIDES
CHLORINE COMPOUNDS
COMPARATIVE EVALUATIONS
COMPLEXES
CONDENSED AROMATICS
DATA
EMISSION SPECTROSCOPY
ENERGY
ENTHALPY
ENTROPY
EQUILIBRIUM
EXPERIMENTAL DATA
FLUORESCENCE SPECTROSCOPY
FREE ENERGY
HALIDES
HALOGEN COMPOUNDS
HYDRAZINE
HYDROGEN COMPOUNDS
INFORMATION
MEDIUM TEMPERATURE
MICELLAR SYSTEMS
NITROGEN COMPOUNDS
NMR SPECTRA
NUMERICAL DATA
ORGANIC COMPOUNDS
ORGANIC SULFUR COMPOUNDS
OXYGEN COMPOUNDS
PERYLENE
PHYSICAL PROPERTIES
QUANTITATIVE CHEMICAL ANALYSIS
QUANTITY RATIO
SAMPLE PREPARATION
SODIUM CHLORIDES
SODIUM COMPLEXES
SODIUM COMPOUNDS
SOLVENT PROPERTIES
SPECTRA
SPECTROSCOPY
STRUCTURAL CHEMICAL ANALYSIS
SULFONATES
SYNTHESIS
TEMPERATURE DEPENDENCE
THERMODYNAMIC PROPERTIES
THERMODYNAMICS
WATER