Banca de DEFESA: RENAN DA SILVA NUNES
Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.DISCENTE : RENAN DA SILVA NUNES
DATA : 03/02/2020
HORA: 14:00
LOCAL: campus Santo Andre
TÍTULO:
PRODUCTION AND APPLICATION OF KRAFT LIGNIN SULFONATED CARBONS IN THE FRUCTOSE DEHYDRATION REACTION UNDER CONVENTIONAL AND MICROWAVE HEATING
PÁGINAS: 115
GRANDE ÁREA: Ciências Exatas e da Terra
ÁREA: Química
SUBÁREA: Química Inorgânica
ESPECIALIDADE: Físico Química Inorgânica
RESUMO:
Kraft Lignin is a byproduct of the pulp and paper manufacture that use the Kraft Process in their production chain. This material has promising properties for high added value and nobility applications. However, simply and efficiently valorization of Kraft Lignins remains a challenge. In this context, the present work proposed new preparation methodologies for obtaining sulfonated acid carbons using two types of kraft lignins (hardwood - eucalyptus and softwood - conifers) by applying in situ carbonization with H2SO4. The carbons were designed with the purpose of applying them as low-cost catalysts in the fructose dehydration reaction to obtain 5-hydroxymethylfurfural, one of the most important platform compounds for biorefinery. The methodology of this work consisted of investigating the effect of fractionation and thermal pretreatment processes of kraft lignins, combined or not, on the physicochemical and catalytic properties of the obtained carbons. The effect of each of the methodologies on the carbons properties has been extensively investigated employing a wide range of characterization techniques. Finally, the best catalyst produced in this work was applied in the dehydration reaction of fructose under microwave heating. After kinetic and optimization studies, 93.3% of fructose conversion with 98% selectivity for 5-HMF was obtained in record reaction time (10 s), mild temperature (120 °C) and using a concentrated fructose solution (10% w/v in DMSO). The catalyst produced can be easily regenerated and recycled for use in consecutive catalytic cycles. The material's performance was superior to high cost commercial catalysts. Finally, based on the results obtained here and in literature, it was possible to propose a mechanism for fructose dehydration in the presence of the sulfonated carbon produced in this work.
MEMBROS DA BANCA:
Presidente - Interno ao Programa - 1601156 - WAGNER ALVES CARVALHO
Membro Titular - Examinador(a) Externo ao Programa - 1961116 - DEMETRIO JACKSON DOS SANTOS
Membro Titular - Examinador(a) Externo à Instituição - DANIELLE DA COSTA RUBIM MESSEDER DOS SANTOS
Membro Suplente - Examinador(a) Interno ao Programa - 2351974 - JULIANA DOS SANTOS DE SOUZA
Membro Suplente - Examinador(a) Externo ao Programa - 1604147 - LEONARDO JOSE STEIL