Banca de DEFESA: LUCAS NATA DE MELO

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
STUDENT : LUCAS NATA DE MELO
DATE: 10/07/2023
TIME: 14:00
LOCAL: PLATAFORMA RNP
TITLE:

Study of the chemical interesterification process of vegetable oils, focusing on the self-interesterification castor oil, and evaluation of the potential use of its reaction products

 

KEY WORDS:

Biodiesel; biolubricants; interesterification; transesterification; ricinoleic acid; estolides. 

PAGES: 175
BIG AREA: Ciências Exatas e da Terra
AREA: Química
SUMMARY:

In this work, the results and partial discussions of studies on the transesterification of binary mixtures between castor (OM), soybean (OS) and coconut (OC) oils in the presence of methanol and NaOH, before and after interesterification, in the latter case in the presence of CH3OK as a catalyst, are reported considering that there are no reports in the literature comparing transesterification reactions of mixtures of different sources of triacylglycerols (TAGs) with the same fatty acid composition. For cases in which OM is not present, studies have shown that random redistribution of fatty fragments in TAGs does not significantly affect the kinetic behavior of the transesterification reaction. On the other hand, binary mixtures containing OM, before and after interesterification, showed different kinetic profiles. In other words, the kinetics of the transesterification reaction does not depend only on the fatty acid composition of the oils used when utilizing OM as a source of TAGs. From the results obtained so far, it was found that during interesterification of the mixtures containing this oil, a parallel transesterification reaction occurs. It was confirmed that the hydroxyl group present on the 12th carbon of the ricinoleic portion of the OM acts as a transesterification agent in the interesterification conditions adopted in this work. In these cases, increases in viscosity in relation to physical mixtures containing OM (from 14 to 93%) and peaks of high retention times in high performance liquid chromatography (HPLC) determinations were observed. Carbon-13 nuclear magnetic resonance (NMR 13C) analyzes confirmed that during the interesterification reaction in the presence of OM, acylglycerol estolides are formed, which explains the lower transesterification rates for interesterified mixtures. This is the first time that the production of estolides, fatty acid ester oligomers, has been reported under TAG interesterification conditions. Quantitative 13C NMR studies indicated high degrees of esterification (72-97%) for the samples produced. In order to better understand the reaction process under study, the same reactions were performed with raw OM. After OM interesterification reaction, the formation of acylglycerol estolides was observed, as well as the formation of di- and monoacylglycerols, in addition to glycerol. There was also an increase in the degree of oligomerization and viscosity of the material obtained with increasing reaction time and temperature. The sample with the highest kinematic viscosity at 40 °C showed an increase of 146% compared to OM. Infrared spectroscopy characterizations helped to confirm the formation of estolides from the gradual reduction of the band related to the O-H bond. Due to the characteristics of the material obtained after interesterification, its potential application as lubricants was investigated. In relation to the estolides reported in the literature and commercial lubricants with similar viscosities, the products obtained in this work presented advantages regarding the production process and most of the physical properties evaluated, attesting to the potential of industrial application of these materials. As a continuation of this work, it is intended to study kinetically the formation of acylglycerol estolides under the adopted conditions and to proceed with the physico-chemical characterization of the products.

BANKING MEMBERS:
Externo(a) à Instituição - IZABEL CRISTINA RIEGEL VIDOTTI MIYATA
Presidente - 1904678 - JANAINA HEBERLE BORTOLUZZI
Interno(a) - 1348288 - MARIO ROBERTO MENEGHETTI
Interno(a) - 1515173 - SIMONI MARGARETI PLENTZ MENEGHETTI
Externo(a) à Instituição - WAGNER ALVES CARVALHO
Interno(a) - 1697766 - WANDER GUSTAVO BOTERO