Banca de DEFESA: ANDERSON JOEL SCHWANKE

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
DISCENTE : ANDERSON JOEL SCHWANKE
DATA : 05/12/2016
HORA: 08:30
LOCAL: Sala de Aula PPGCEM
TÍTULO:

Hierarchical MWW-type zeolites by soft and hard templates – Niobium insertion and catalytic activity.

PALAVRAS-CHAVES:

hierarchical zeolites, MWW, niobium, MCM-22, fructose dehydration to 5-HMF

PÁGINAS: 114
GRANDE ÁREA: Engenharias
ÁREA: Engenharia de Materiais e Metalúrgica
SUBÁREA: Materiais Não-Metálicos
ESPECIALIDADE: Cerâmicos
RESUMO:

The synthesis of MWW-type hierarchical zeolites were done using soft and hard templating approaches. The materials were characterized by various techniques such as XRD, ATG, ICP, N₂ adsorption isotherms, SEM, TEM, UV-vis and FTIR with pyridine adsorbed spectroscopies. The soft template strategy was done using swelling agents with different molecular dimensions in different treatments (soft and aggressive). It was observed that swelling agents and the type of treatment (soft or aggressive) influences the pore architecture generating pillared, disorganized and desilicated materials. The aggressive treatment damages the MWW structure which creates accessibility regions due to the broken layers which result an increase of catalytic activity for the conversion of fructose to 5-hydroxymethylfurfural (5-HMF) and similar with materials treated on soft swelling procedure. For pillared MWW zeolites with Si/Nb as mixed pillars, the niobium insertion increases the Lewis acidity after pillaring. Niobium is present as mononuclear species in tetrahedral coordination with silica pillars where its gradual increase of Si/Nb molar ratios higher than 60 decrease the interlayer mesoporosity created by pillaring. The use of carbon BP 2000 as hard template in the synthesis of MCM-22 zeolite was effective for the final control of microspherical-type morphology. The synthetic procedure in stumbling and the particularly tortuous shape of agglomerated BP 2000 particles interacts with the zeolitic nuclei. The crystals growth occurs in house of cards-type orientation creating meso/macro voids in entire of microspheres with sizes between 6-10 µm. The control of morphology in microspheres in acidic form does not affect the catalytic activity compared to traditional synthesis of MCM-22 in acidic form. The microspheres was impregnated with niobium and demonstrated synergy between the acidity of the zeolite and the metal having higher catalytic activity for the conversion of fructose to 5-HMF its acidified form in the first 45 minutes of reaction. It was demonstrated that soft and hard template strategies are potential and attractive approaches for create hierarchical porosity and morphologic control in MWW-type zeolites.

MEMBROS DA BANCA:
Interno - 349770 - DULCE MARIA DE ARAUJO MELO
Externo à Instituição - HELOISE DE OLIVEIRA PASTORE - UNICAMP
Externo à Instituição - MARCO ANDRE FRAGA - INT
Presidente - 1308577 - SIBELE BERENICE CASTELLA PERGHER
Externo ao Programa - 2087667 - TIAGO PINHEIRO BRAGA