Comparative Study Between Traditional and Mannich Base as Lubricant Oil AntioxidantsAuthor(s): Mohamad Gamil Abdalghani
Mannich base was prepared by using pentane diamine, p-octyl phenol, and formaldehyde in existence of nitrogen gas environment. FTIR spectroscopy was used to prove the structure of the product. The behavior of the base as antioxidant for lubricant oil was examined through viscosity, acid number and density variation compared with lubricant oil sample containing no additives. A percent of 2% of the product was added to a sample of crude lubricating oil type SAE 50 furnished from Al-Dora refinery. The obtained formulation was kept under elevated oxidation conditions at 393 K, in existence of 0.1% of benzoyl peroxide as free radical initiator for oxidation process, the oxidized samples were taken at periods of 4 h up to 24 hours. The results showed that during the oxidation process, the values of acid number were increased, and there was a decrease in the density and viscosity values for the non-formulated samples in a comparison with those contained a percent of Mannich base in which the studied parameters were kept with no changes in their initial values. The induction period during the oxidation process for the base was done by dissolving 2% of the base in a sample of lubricant oil and subjected to elevated temperature 393 K in existence of 0.1% of benzoyl peroxide by Manometric instillation device based on chemiluminescence mechanism. The behavior of prepared base was compared with traditional universal antioxidants. The results showed an increase in the induction periods for Mannich base during the oxidation operation than those shown in traditional types confirming their high performance.