Banca de QUALIFICAÇÃO: POLIANA PINHEIRO DA SILVA

Uma banca de QUALIFICAÇÃO de DOUTORADO foi cadastrada pelo programa.
STUDENT : POLIANA PINHEIRO DA SILVA
DATE: 21/06/2023
TIME: 16:00
LOCAL: Videochamada online
TITLE:

PRODUCTION OF VALUABLE CHEMICAL PRODUCTS: SYNTHESIS OF LEVULINIC ACID FROM GREEN COCONUT HUSK POWDER AND COMPARATIVE STUDY OF THE SYNTHESIS OF LEVULINATES

KEY WORDS:

thermogravimetry, green coconut, levulinate, conversion, fuel

PAGES: 110
BIG AREA: Engenharias
AREA: Engenharia Química
SUBÁREA: Tecnologia Química
SPECIALTY: Tratamentos e Aproveitamento de Rejeitos
SUMMARY:

Sustainable chemical products are being increasingly studied, one of the alternatives is production from biomass, a resource generated in large quantities and which is most often discarded in landfills or even in vacant lots. Levulinate esters and levulinic acid are examples of these products, these are the basis for several industrial products of great value, as well as being used as fuel additives. The thesis study is divided into three main stages, the first determined the biomass composition before and after esterification through thermal analysis; a reduction in the amounts of cellulose and hemicellulose was noticed after the reaction, cellulose decreased from 18.18% to 9.77% and hemicellulose from 44.65% to 26.18%. Then, the degradation kinetics was performed using the Ozawa–Flynn–Wall method, which demonstrated that the activation energy is directly related to the presence of hemicellulose and cellulose, changing from 143 kJ.mol-1 to 125 kJ.mol- 1. The second stage consisted of the synthesis of levulinic acid generated from the powder of green coconut shell; the reactions took place in a Parr Instruments stainless steel reactor, with a capacity of 300 mL and the samples were analyzed in HPLC, the conditions of the reactions were determined according to a factorial design with the addition of 3 points, for this study the factors studied were: temperature, time and amount of catalyst being the three significant; the response variable was levulinic acid yield, which reached a maximum of 42.94% in central conditions (190ºC, 2hrs, 1:0.25). The third study comprised a three-factor Box-Behnken (PBB) design, with the response being the conversion of levulinic acid into ethyl levulinate, the highest conversion taking place in 1hrs, molar ratio 4:1 and catalyst concentration 0.04mol /L. Then, a comparison was made between the synthesis of methyl and ethyl levulinate, where it was noticed that the only significant factor in both reactions was time.

COMMITTEE MEMBERS:
Presidente - 1308273 - EDUARDO LINS DE BARROS NETO
Interno - 1670497 - HUMBERTO NEVES MAIA DE OLIVEIRA
Externo ao Programa - 1566922 - LINDEMBERG DE JESUS NOGUEIRA DUARTE - UFRNExterna à Instituição - LEONETE CRISTINA DE ARAUJO FERREIRA MEDEIROS SILVA - UFERSA
Externa à Instituição - PAULA FABIANE PINHEIRO DO NASCIMENTO - UFRN