Oxidation of cyclohexane in air produces cyclohexanone and cyclohexanol in cyclopol-bis process along with waste water stream containing valuable carboxylic acids. Process is devised in this manuscript to prepare complex polyol ester base oil by utilizing the waste water. The waste water stream from the cyclohexane oxidation process of Gujarat state fertilizers and chemicals ltd. has been vacuum distilled with a vacuum of 700 mmHg to remove water followed by filtration to separate the solid and liquid fractions. The liquid fraction is reacted with diethylene glycol to synthesize complex polyol ester base oil for lubricant. The base oil so obtained has a kinematic viscosity of 113 cSt at 40 degrees C, pour point of -33 degrees C and viscosity index of 109.