Síntese e caracterização de ésteres a partir do diglicerol e triglicerol e avaliação de suas aplicações em lubrificantes

Abstract

The increased environmental conscience gives impetus to the development of new bioproducts. Diglycerol and triglycerol esters were synthesized and its lubricating properties were evaluated. Linear diglycerol was regenerated from the diglycerol isopropylidene obtained by reaction mixture alkaline glycerol polymerization with acetone. In the esterification and transesterification reactions were used oleic acid (OA) and undecylenic acid (UA) and the esters methyl oleate (MO) and epoxidized methyl oleate (EMO), respectively, with 100% excess with respect to alcohol. The esters were purified by column chromatography and their structure confirmed by 1H and 13C NMR and FTIR. The main properties evaluated were kinematic viscosity at 40 and 100 °C, viscosity index, density at 40 °C, thermo-oxidative stability (by TGA) and pour point (by DSC). All esters showed high viscosity index (154-198). The ester of diglycerol with epoxidized methyl oleate (DGEMO) showed higher viscosity and thermo-oxidative stability and the ester of diglycerol with undecylenic acid (DGUA), lower viscosity and thermo-oxidative stability. The DGMO showed the lowest melting point (-44°C) and DGEMO the highest melting point (+9°C). Using a 5% concentration, the increase in the pure paraffinic oil (PPO) viscosity index was up to 8.2 with DGOM. Furthermore, the esters have not changed, in the concentration of 5% v / v, the PPO melting point values that make them dull.