Novel Acyl Derivatives from Karanja Oil: Alternative Renewable Lubricant Base Stocks

Bio-additives Derived from Ricinoleic Acid and Choline with Improved Tribological Properties in Lithium Base Grease

In this study, bio-based ionic liquid prepared from ricinoleic acid and choline was firstly used as additive in lithium base grease. The characterization and tribological performance of the prepared ionic liquid ([cho][ricinoleic]) as additive in grease were studied compared with the traditional ionic liquid such as L-P104. All the concentrations showed promising friction-reducing and anti-wear properties, though a 3% concentration has superior lubricating properties than others. Furthermore, [cho][ricinoleic]) can greatly enhance the lubrication capability of lithium base greaseunder different frequency and load at room temperature. Although L-P104 showed good lubricating performance than [cho][ricinoleic] at 150°C, the chosen formulation (1.5% [cho][ricinoleic] + 1.5% L-P104) could have better synergism at high and room temperature, which could be a good supplement to ionic liquid as grease additive. Thin films formed according to the results of SEM and XPS were attributed to be the main account for the preferable tribological properties of [cho][ricinoleic] in lithium base grease.

Ester Oils Prepared from Fully Renewable Resources and Their Lubricant Base Oil Properties

The work reports on the physicochemical and tribological properties of gallate ester oils prepared from fully renewable resources, such as gallic acid and fatty acids. The ester structures were identified by proton nuclear magnetic resonance spectroscopy (1H NMR), carbon nuclear magnetic resonance spectroscopy (13C NMR) and high-resolution mass spectra (HRMS) data. The density at 20 °C (d 20), kinematic viscosity (KV), viscosity index (VI), pour point (PP), flash point (FP), thermal and oxidative stabilities, friction-reducing and antiwear properties of gallate ester oils were evaluated. The tribological properties of gallate ester oils as lubricants for steel, copper, and aluminum tribo-pairs can be compared with those of the commercially available lubricating oil tris(2-ethylhexyl) trimellitate (Phe-3Ci8), but their viscosity-temperature characteristics, thermal and oxidative stabilities are better than those of Phe-3Ci8. More importantly, they have much higher biodegradabilities than Phe-3Ci8. The study of the lubrication mechanism shows that the physical and/or chemical adsorption film formed by gallate ester molecules between friction pairs is the key factor for them to obtain friction-reducing and antiwear properties.