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This study reports the synthesis of bio-based lubricants using pequi oil (PO) as a raw material, along with its chemical, thermal, and rheological characterization, as well as its cytotoxic behavior and the kinetic study of the reaction involved in the production of biolubricants. Free fatty acid pequi oil (PFFA) was esterified using 2-ethyl-1-hexanol (P2EHE), pentaerythritol (PPEE), and p-TSA as catalysts. The 1 H NMR spectra confirmed the replacement of hydroxyl groups of both alcohols by PFFA. PPEE showed better thermal stability (T onset 274.50 °C). Besides, at 50% of thermal weight loss, the PPEE showed a higher decomposition temperature (437.9 °C) than PO (366.6 °C). The melting points determined by DSC indicate that P2EHE exhibits better performance at low temperatures (p.p. −22.86 °C) than PPEE (p.p. −33.28 and 8.02 °C) due to the presence of some crystals of saturated fatty acids in the pentaerythritol ester. The esters showed Newtonian behavior in a wide range of shears; however, they showed pseudoplastic behavior at temperatures above 60 °C. The viscous nature of bio-based lubricants was confirmed (G″ > G′) even with increasing temperature. The kinetic study provided the value of the activation energy to P2EHE and PPEE, similar to that reported in the literature for other types of biolubricants. The toxicity analysis of bio-based lubricants on adult zebrafish showed no lethality after 96 h. These results suggest that pequi oil is a potential raw material to produce lubricants that are less harmful to the environment.

Fish farming is a worldwide growing activity and a large amount of residues is produced in this process. The present work describes a cleaner and sustainable way to produce new lubricants from fish waste oil. Oil extracted from the Nile tilapia (Oreochromis niloticus) viscera was utilized as raw material to produce basic oil for lubricants. The products were synthesized by esterification with polyols, trimethylolpropane (TMP) and pentaerythritol (PE), using p-toluenesulfonic acid (p-TSA) as catalyst. The synthesized esters were characterized by infrared (IR) and nuclear magnetic resonance (NMR). Computational methods were used to predict the physical characteristics of the material. In addition, the main physicochemical properties were evaluated, as well as the thermal behavior and toxicity of the products against Artemia salina. The synthesized esters showed high viscosity indexes (VI > 150) and viscosities that fit the degree of application ISO-46 and 150. Molecular dynamics simulations indicated that at room temperature the lubricants Tilapia fatty acid -trimethylolpropane ester (T-TMPE) and Tilapia fatty acid -pentaerythritol ester (T-PEE) are in liquid and gel states, respectively, confirming the experimental data. The products did not present toxicity against A. salina. In this research, we reinforce the potential of using tilapia oil from waste to produce green lubricants as a strategy to reduce damage to the environment, as well as the use of computational methods that collaborate to predict physical properties of lubricants.