Infrared spectroscopy stearic acid

The corrosive activity on copper/lead bearings for typical carboxylic acids, such as decanoic, lauric, palmitic, stearic, and oleic acids, as 1 % w/w solutions in a lubricating oil base stock with excess of hard-core RMs, measured by infrared spectroscopy, supports the observation for the corrosive activity of used lubricating oils. An increase in total acidic number (TAN) is generally either an indication of contamination with acidic combustion products or the result of oil oxidation. Corrosion of bearing metals by used lubricating oils requires the presence of both acids and peroxides and probably takes place by a two-step mechanism. In the first step, the peroxide reacts with the metal to form a metal... 

Nimaiyar et al. (2004) also found stearic acid to be the most difficult fatty acid to predict using Fourier-Transform near-infrared spectroscopy over the 833 to 2500 nm range. Stearic acid had the lowest R value and lowest RPD value of all five fatty acids tested. 

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