NMR ANALYSIS OF MIXED PENTAERYTHRITOL DIPENTAERYTHRITOL, AND 1, 1, 1-TRIMETHYLOPROPANE ESTERS.
NAVAL RESEARCH LAB WASHINGTON D C
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Benzene solutions of mixed pentaerythritol, dipentaerythritol, and 1, 1, 1-trimethylolpropane esters may be quantitatively assayed by proton NMR spectroscopy with an absolute accuracy of 5 mole- for each of the ester types. Higher accuracies are possible if a calibration curve is used. Average acid chain length and the approximate degree of chain branching are also obtained. The NMR method can be used for monitoring base stocks, checking blend compositions, and determining constancey of formulation of oils qualified under specification MIL-L23699. NMR analyses of a group of commercial esters and of several aircraft engine lubricant formulations were made. Results were obtained on both the Varian A-60 and HA-100 spectrometers, with comparable accuracy. The A-60 is felt to be the preferred instrument, however, because its integrals are simpler to process. Author