Determination of iodine value of lubricating oils by nuclear magnetic resonance (NMR) spectroscopy

A direct, quick and non-destructive method for estimating the iodine value of fats, fatty oils and their blends in mineral oils has been developed based on {sup 1}H and {sup 13}C-NMR spectroscopy. The method involves the determination of unsaturation content of the samples by {sup 1}H and {sup 13}C-NMR spectroscopic techniques. The iodine value of the sample is directly proportional to the unsaturated proton or carbon content. The value of the proportionality constant is independent of the nature of the fats and their blends in mineral oils for the limited samples studied. The iodine value determined by this method also includes the contribution from additives containing unsaturation. Saturated ingredients in the sample do not contribute to the iodine value as is the case with the standard IP-84 method. 5 refs., 3 figs., 4 tabs.