Banca de DEFESA: EVELLYN PATRICIA SANTOS DA SILVA

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : EVELLYN PATRICIA SANTOS DA SILVA
DATE: 22/02/2021
TIME: 14:00
LOCAL: webconferência via Google Meet
TITLE:

Esterification of levulinic acid in the presence of alcoholic agents using Sn (IV) based catalysts

KEY WORDS:

biomass, catalysis, organotin (IV), levulinate esters.

PAGES: 66
BIG AREA: Ciências Exatas e da Terra
AREA: Química
SUBÁREA: Química Inorgânica
SUMMARY:

Lignocellulosic biomass represents an abundant and relatively low-cost renewable carbon resource that can be used to produce chemical inputs, such as levulinic acid (LA). This keto acid is a versatile platform for a wide variety of applications that can replace or complement fossil sources, which is desirable to improve global sustainability. Derivative esters of levulinic acid can be developed as promising additives to oxygenate fuels, which not only increases the efficiency of the engine, but also decreases gaseous and particulate emissions. Thus, the present work aims to evaluate catalytic systems based on tin (IV), compared to reactions without the use of catalyst, in the esterification of levulinic acid with ethanol (EtOH) to produce levulinate esters. Initially, the reactions were conducted at 70 º C in reaction times ranging from 0.25 to 6h with molar proportions of AL / EtOH / CAT of x / y / z, where x = 1, y = 5 and z = 0 , 01 and stirring speed of 1000 rpm. The experiments were carried out in closed glass reactors of the vial type. The quantification of the remaining levulinic acid in the reaction mixtures was performed by high performance liquid chromatography (HPLC) and the results were expressed in terms of conversion (%) of the levulinic acid. The catalysts were characterized by absorption spectroscopy in the region of the middle infrared with Fourier transform (FTIR) and it was possible to confirm their chemical structures. The initial results showed that the organometallic butyl tin trichloride (BTC) complex showed better catalytic activity with 71.4% conversion of levulinic acid in 6 hours of reaction, under the conditions studied. Such efficiency may be associated with the increase in Lewis acidity in the metal center due to the presence of electronegative substituents and physical compatibility of the catalyst in the reaction medium.

BANKING MEMBERS:
Externo ao Programa - 1545506 - ANTONIO OSIMAR SOUSA DA SILVA
Interna - 1904678 - JANAINA HEBERLE BORTOLUZZI
Externo à Instituição - PAULO ANSELMO ZIANI SUAREZ - UnB
Presidente - 1515173 - SIMONI MARGARETI PLENTZ MENEGHETTI
Interno - 1697766 - WANDER GUSTAVO BOTERO