Effect of aromatics and iso-alkanes on the pour point of different types of lube oils

In this work, we have studied the quantitative composition of seven lube oils obtained from different refineries by Nuclear Magnetic Resonance (NMR) spectroscopy and Gas Chromatography (GC) methods. A trend of low temperature flow behavior of these lube oils has been correlated with the composition, i.e. n-alkane, iso-alkanes and aromatics. The pour point of these lube oils does not depend only on distribution of n-alkanes, rather with quantity and types of other molecules like iso-alkanes and aromatics. Two alkylacrylate co-polymers with different mole fractions of co-monomers synthesized by free radical mechanism are used as pour point depressant (PPD) additives. Effectiveness of additive is dependent on polar aromatic type molecules along with iso-alkane type molecules in lube oil.