IR-Spectrometric Determination of 2,6-Di-tert.-butyl-p-cresol in Aviation Lubricating Oil and Hydraulic Press Oil

The anti-oxidant,2,6-di-tert.-butyl-p-cresol (DBpC),in aviation lubricating oil and hydraulic press oil was determined by IR spectrometry with compensation by optic attenuator.IR spectrum in the wave number range of 3 760-3 550 cm-1 was recorded.Absorbance due to the stretching vibration of OH group in the molecule of DBpC at the wave number of 3 650 cm-1 was calculated by the baseline method,and content of DBpC was found from the working curve.Range of linearity was found in the range of 0.05%-0.10% (w% of DBpC),corresponding to the linear regression equation A=0.003 03+0.560 81 C (r=0.998 0).