8-Nitroxide methyl palmitate

The 12-nitroxide stearic acid and the 8-nitroxide methyl palmitate were donated by J. D. Morrisett (John Baylor College of Medicine, Houston, Tex.). All other nitroxide stearic acid and stearate probes were purchased from Syva (California). All probe molecules were subsequently purified by preparative thin layer chromatography (TLC) until a single spot was obtained under all development conditions. TLC was carried out in a dry nitrogen atmosphere to avoid possible oxidation or hydrolysis during purification. Ultrapure silica gel, free from any plasticizers, was used to avoid possible further contamination. 

The results are shown in Figures 1 through 7. Figures 1 through 6 show isotherms over a range of temperatures for the 5-, 12-, and 16-nitroxide stearic acids, for the 5- and 16-nitroxide methyl stearates, and for the 8-nitroxide methyl palmitate over the range 9°-50°C. [We use 5-NS, 5-NS(Me), and 8-NP(Me) for the trivial names 5-nitroxide stearic acid, 5-nitroxide methyl stearate, and 8-nitroxide methyl palmitate, with... 

Figure 3. Surface pressure (dynes/cm) vs. area/ molecule (A2) for 8-nitroxide methyl palmitate [8-NP(Me)] at 9% 20% 30% and 40°C. Broken line indicates a near liquid-like film collapse.

Isotherms for monomolecular films of a series of nitroxide stearic acid and nitroxide palmitate and stearate (methyl ester) films are reported for the temperature range 9° 50°C. 

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