Resumo Amostras de nontronita pilarizadas com alumínio (Pt/Al-PilM) e alumínio-lantânio (Pt/AlLa-PilM) foram preparadas a partir de nontronita natural, caracterizadas e testadas como catalisador na reação de hidroisomerização do n-octano. Os resultados foram comparados com os obtidos da mesma reação, usando zeólita Y comercial impregnada com platina (Pt-Y). Experimentos com zeólita comercial mostraram que a platina é essencial para manter a seletividade reacional dos produtos. A capacidade de conversão das amostras (Pt/Al-PilM) e (Pt/AlLa-PilM) foram 70% e 40% respectivamente, superando o desempenho de 30% da Pt-Y, mas com a mesma seletividade. Os resultados de difração de raios X mostraram que a oxidação da matéria orgânica seguida da homogeneização catiônica é de suma importância para preparação da argila pilarizada.

Abstract Nontronite samples pillared with aluminium (Pt/Al-PilM) and aluminium-lanthanum (Pt/AlLa-PilM) were prepared from natural nontronite, characterized and tested as catalyst in n-octane hydroisomerization reaction. The results were compared with those obtained from the same reaction using commercial Y-zeolite impregnated with platinum (Pt-Y). Experiments with commercial zeolite show that platinum is essential to maintain the reactional selectivity of the products. The conversion capacities of (Pt/Al- PilM) and (Pt/AlLa-PilM) were 70% and 40%, respectively, surpassing the Pt-Y performance of 30%, but with the same selectivity. X-ray diffraction data show that organic matter oxidation followed by cationic homogenization is of paramount importance for pillared clay preparation.

The CO2 reforming of CH4 was carried out over Ni catalysts supported on γ -Al2O3 and CeO2-promoted γ -Al2O3. The catalysts were characterized by means of surface area measurements, TPR, CO2 and H2 chemisorption, XRD, SEM, and TEM. The CeO2 addition promoted an increase of catalytic activity and stability. The improvement in the resistance to carbon deposition is attributed to the highest CO2 adsorption presented by the CeO2 addition. The catalytic behavior presented by the samples, with a different CH4/CO2 ratio used, points to the CH4 decomposition reaction as the main source of carbon deposition.

Neste trabalho são apresentados os procedimentos de preparação de materiais cerâmicos de SiO2, SnO2 e Al2O3 e, também, suas propriedades catalíticas nas reações de reforma do metano e do metanol. As análises dos resíduos de carbono, após testes catalíticos, sugerem que a modificação estrutural dos catalisadores pode minimizar os efeitos de sua desativação.

This work presents the procedures for preparing SiO2, SnO2 and Al2O3 ceramic materials and also their catalytic properties for the reforming reactions of methane and methanol. The analyses of the carbonaceous residues suggest that the structural modification of the catalyst can minimize the deactivation effect upon them.

The kinetics of the gas-phase isomerization of β-pinene over an acid-activated bentonite clay has been investigated in a fixed-bed continuous flow reactor, at atmospheric pressure between 58 and 90 oC. The major isomers produced were camphene, α-pinene and limonene. The reaction rates of β-pinene conversion and the apparent activation energy were determined. The kinetics of β-pinene isomerization was described by zero-order kinetics with an activation energy of 30-35 kJ/mol for the major products formed.