In-Situ Epoxidation of Waste Cooking Oil and Its Methyl Esters for Lubricant Applications: Characterization and Rheology

Abstract

In the present investigation, in-situ epoxidation of waste cooking oil and its methyl esters was prepared, and the rheological behavior was analyzed for biolubricant applications. Rheological properties of the prepared epoxides were measured at a temperature of 25–100 °C, at a shear rate ranging from 5 to 300 s−1. As viscosity is one of the critical parameters for potential biolubricant applications, in the present study, the power-law model was used to investigate the flow behavior of the epoxides. The viscosity of epoxidized waste cooking oil and its methyl ester epoxides showed Newtonian flow behavior in the studied temperature range. Different shear rates (5–100, 5–300, 100–300 s−1) were studied to determine the shear rate dependency of the epoxidized waste cooking oil and its methyl ester epoxides at different temperatures. From the average viscosity values, it was shown that the epoxides show identical results at all shear rates. The dynamic viscosities of the epoxidized waste cooking oil and its methyl ester epoxides were found to be dependent on fatty acid chain length, unsaturation, and temperature. Detailed physicochemical characterization for epoxide waste cooking oil (EWCO) and epoxide waste cooking oil methyl esters (EWCOME) were carried out to evaluate the properties for suitable biolubricant applications using standard American Society for Testing and Materials (ASTM) and American Oil Chemists’ Society (AOCS) methods. Based on the viscosity for EWCO (278.9 mm2/s) and EWCOME (12.15 mm2/s) and viscosity index for EWCO (164.94) and EWCOME (151.97) of the prepared epoxides, they could complement the standard ISO vegetable grade (VG) lubricants in the market.

Thickening Castor Oil with a Lignin-Enriched Fraction from Sugarcane Bagasse Waste via Epoxidation: A Rheological and Hydrodynamic Approach

“…The formation of the epoxy ring produces an enhanced steric hindrance as a consequence of new dipole−dipole interactions among molecules, which tend to cluster, hindering their flow and increasing the viscosity. 28,29 However, as reported elsewhere, 30,31 the Newtonian character was not altered over the range of epoxidation degrees achieved.…”

Characterization, kinetics and thermodynamics of epoxidation-esterification of Irvingia gabonensis kernel oil methyl ester

“…Nevertheless, for the modified oil sample obtained by epoxidation-esterification of Irvingia gabonensis kernel oil methyl ester (MIGKO e ), its moisture content was found to be lower than the 1.9 , reported for bio-transformer fluids obtained from palm oil; but the same as the 1.0 obtained from coconut ( Aimi and Hussin, 2014 ). However, the moisture content of MIGKO e in this work was higher, compared to 0.18 for epoxidized waste cooking oil methyl ester ( Paul et al., 2021 ) and 0.65 for epoxidized Terminalia catappa L. kernel oil methyl ester ( Agu et al., 2019 ). As earlier reported for vegetable oils, the differences in moisture contents of MIGKO e sample, and those of bio-transformer fluids produced from coconut, Terminalia catappa L. kernel and palm oils, were linked to extraction and modification methods adopted ( Agu et al., 2019 ).…”

“…(2020) and Borugadda and Goud (2014) , respectively. On the other hand, the density (840 ) of MIGKO e sample was higher than 773.8 , reported for epoxidized waste cooking oil methyl ester, by Paul et al. (2021) .…”

“…Pour point of MIGKO e was less than -8 , 2.40 , 4 °C and 8 °C values, reported by Agu et al. (2019) , Paul et al. (2021) , Oyelaran et al.…”

Potential of the Red Alga Dixoniella grisea for the Production of Additives for Lubricants

“…These properties are supposed to stabilize the lubricant film thickness when high pressures occur, e.g., in rolling bearings of a high load [ 14 ]. High viscosities are considered favorable for lubrication as viscosity controls the lubrication film thickness [ 24 ]. Arad et al [ 25 ] state that at high pressures, high loads and low sliding velocities, the main friction mechanism is boundary lubrication.…”