Synthesis, characterization and application of polyesters from diglycerol and triglycerol as lubricants and additives

Abstract Glycerol is produced on a large scale as a byproduct in the biodiesel market. In order to give an application to glycerol, this work uses diglycerol from synthesized polyglycerol and commercial triglycerol in the synthesis of long chain esters obtained from esterification and transesterification reactions with oleic acid, methyl oleate, and epoxidized methyl oleate. Diglycerol tetraoleate (DGMO), epoxidized diglycerol tetraoleate (DGEMO), and triglycerol pentaoleate (TGOA) were synthesized and characterized by 1 H and 13 C Nuclear Magnetic Resonance (NMR) and infrared (IR) spectroscopy. Polyglycerol esters were evaluated for basic lubrication properties such as density, kinematic viscosity, viscosity index, melting point, and thermo‐oxidative stability. The ester that showed best thermo‐oxidative stability was DGEMO. In addition, the influence of esters synthesized as additives in a pure paraffinic oil lubricant was evaluated and the TGOA showed greater change in viscosity at 100 and 40°C and in melting point which was increased by 1.56°C.