Synthesized biolubricants from naturally derived oleic acid: Oxidative stability and cold flow performance

• Published in: Industrial crops and products 2023-11, Vol.204, p.117315, Article 117315
• Main Authors: Sarker, Majher I., Mainali, Kalidas, Sharma, Brajendra K., Yadav, Madhav P., Ngo, Helen, Ashby, Richard D.
• Format: Article
• Language: English
• Subjects: Activation energy; Biolubricants; Differential scanning calorimetry; Oleic acid; Thermogravimetric analysis
• ISSN: 0926-6690; 1872-633X
• DOI: 10.1016/j.indcrop.2023.117315

Bio-lubricants are receiving increased interest due to their environmental advantages over petroleum-based analogues. This research demonstrates the evaluation and comparison of thermal and kinetic properties of bio-lubricants synthesized from naturally derived fatty acids. The oxidative stability of the vegetable oil-based bio-lubricants affects their storage stability and reusability. Five different types of bio-lubricants were previously synthesized from oleic acid, iso-oleic acid, and iso-stearic acid. Thermogravimetric analysis was conducted in the presence of air and nitrogen. Comparative studies of the kinetic parameters under thermal decomposition of each synthesized product show that these bio-lubricants are thermally stable. The calculated activation energy showed that trimethylolpropane iso-oleic acid triester (TMP-IOA) was thermally stable with an average activation energy Ea = 188.4 kJ/mol in an inert environment (Under N2). In the oxidative environment (under air), trimethylolpropane iso-stearic acid triester (TMP-ISA) was found as the most stable bio-lubricant with an Ea= 109.8 kJ/mol. The glyceride-iso-oleic acid triester (GLY-IOA) showed a high range frequency factor indicating complex behavior in an air environment. Among these lubricants, the GLY-IOA exhibited superior cold flow properties as measured using cryogenic differential scanning calorimetry. Overall, these comparative studies confirm that the lubricant-based oils produced using saturated or monounsaturated fatty acid provide a good combination of thermal and oxidative stability along with cold flow properties. •Five synthesized biolubricants have been evaluated for their thermal and cold flow properties.•Synthesized biolubricants exhibit good thermal stability and cold flow properties.•Exhibited properties of the synthesized biolubricants vary with their structural differences.