Marcelo Luis Mignoni

Estudo da síntese da zeólita ZSM-5 a partir de argilas naturais

The synthesis of ZSM-5 zeolite was studied by three synthesis methods: standard synthesis, three day synthesis and synthesis employing clays (kaolin and montmorillonite). The raw materials and prepared materials were characterized by Chemical Analysis by X-Ray Fluorescence (XRF) and X-Ray Diffraction (XRD). The results show that it is possible to synthesized ZSM-5 zeolite using clays as raw materials. Kaolin gives phases of higher crystalinity than montmorillonite.

ESTUDO DA IMOBILIZAÇÃO DE LIPASE EM SÍLICA OBTIDA PELA TÉCNICA SOL-GEL

The objective of this work was the immobilization of the enzyme Candida antarctica lipase B (CAL B) using the sol-gel method of immobilization and three different initiators of the polymerization reaction: one acid (HCl), one basic (NH4OH) and the other nucleophilic (HBr). Tetraethylorthosilicate was used as the silica precursor. The influence of the additive PEG 1500 on immobilization was assessed. The efficiency of the process was evaluated considering the esterification activity of the xerogels. The immobilization process provided enhanced thermal stability, storage and operational aspects relative to the free enzyme. Storage temperature proved one of the main variables to be considered in the process, with the xerogels stored under refrigeration showing better results in terms of residual activity (nearly 200 days with ≥ 90% residual activity of basic and nucleophilic xerogels) when compared with storage at ambient temperature (nearly 40 days). The results demonstrated the possibility of reuse of derivatives and a greater number of cycles (nine), considering a residual activity of 50%.

Estudo da adsorção de compostos sulfurados empregando zeólitas contendo zinco

This paper deals with an adosrption of sulphur compounds employing zeolites containing zinc. The zeolites employed were commercial NaY and Beta. The zinc was incorporated in three levels: 0.5; 1.0 and 5%. The sulphur compounds studied were benzothiophene and dibenzothiofene. The results showed that both zeolites can be employed for adsorption of benzothiophene and dibenzothiophene. The Zn incorporation (0.5%) promotes an increase in zeolites adsorption ability. The DBT adsorbs more than BT, probably because it strongly interacts with zeolite structure. The BT adsorbs more in NaY than in beta probably because the NaY zeolite has a high intern volume. This is not observed for DBT.

Polymerization of Ethylene with Zirconocene Heterogenized on Spherical ZSM-5

Homogeneous polymerization catalysts require large amounts of solvent and cannot control the polymer morphology. In order to solve this issue, a narrow-shaped spherical ZSM-5 zeolite was used in ethylene polymerization as a support for zirconocene (Cp2ZrCl2). Several heterogeneous catalytic precursors were prepared and used in ethylene polymerization reactions, which showed yields (between 980-8019 kg PE mol-1 h-1) and were efficient at promoting morphological replication of the support. So, a well-established protocol for slurry polymerization reaction was found, yielding well-defined polymer particles in an advantageous polymerization process.

Estudo da síntese da zeólita MCM-71

A new kind of material, denominated MCM-71, was synthesized and characterized by several complementary techniques: X Ray Diffractometry, textural analysis by nitrogen adsorption, Scanning electronic microscopy and infrared spectroscopy. MCM-71 zeolite was successfully synthesized by hydrothermal synthesis in the presence of triethanolamine. Mordenite phase as impurity was not detected, otherwise quartz was observed. The MCM-71 sample obtained presented a BET surface area of 20 m2/g in the as synthesized form and of 85 m2/g in protonic form. By SEM was observed crystals with rectangular shape with average size of 2 x 0,2 x 0,05 µm and this crystals were agglomerated in spherical particles with average diameter between 14 and 24 µm.

Immobilization of lipase on mesoporous molecular sieve MCM-48 obtained using ionic solid as a structure director and esterification reaction on solvent-free

Catia S. Z. Battistona,*, Aline M. M. Ficanhab, Katarine L. D. Levandoskib, Bernardo A. da Silvab, Suellen Battistonc, Rogério M. Dallagob and Marcelo L. Mignonib Instituto Federal do Rio Grande do Sul, 999713-028 Erechim – RS, Brasil Departamento de Química, Universidade Regional Integrada do Alto Uruguai e das Missões, 99709-910 Erechim – RS, Brasil Departamento de Engenharia Química, Universidade Federal de Santa Catarina, 88040-970 Florianópolis – SC, Brasil