Authors:Bianca V. Sousa, Karoline D. Brito, José J. N. Alves, Meiry G. F. Rodrigues, Carlos M. N. Yoshioka, and Dilson Cardoso
compliance with environmental regulations. Solid acid catalysts are required for their production and there has been a renewed interest in their use over the last few years [ 1 , 5 ].
Bifunctional metal/acid catalysts are used in industrial
Authors:K. V. Novikova, M. O. Kompanets, O. V. Kushch, S. P. Kobzev, M. M. Khliestov, and I. O. Opeida
calculated from the slope of the linear plots of the volume of oxygen uptake vs. time. All kinetic measurements were carried out by using freshly prepared samples.
The catalysts were characterized by comparison of their physical properties with those
Authors:Szabolcs Harnos, György Onyestyák, and Dénes Kalló
vegetable oil at moderate temperatures (300–420 °C) with hydrogen at elevated pressures (20–100 bar). Conventional hydrodesulfurization (HDS) catalysts, such as sulfided CoMo, NiMo, or NiW supported on alumina have achieved the complete conversion of
Acid catalysis plays a vital role in many important reactions of the chemical and petroleum industries, and environmentally benign chemical processes [ 1 – 3 ]. The use of liquid phase acid catalysts suffers from
Authors:Valeria Palermo, Ángel G. Sathicq, Patricia G. Vázquez, Horacio J. Thomas, and Gustavo P. Romanelli
variety of acid-catalyzed reactions such as esterification, etherification, olefin hydration, and dehydration of alcohols, and are also attractive as catalysts for oxidation processes [ 2 ]. Recently, we have used Keggin heteropolyacids in a range of
Zirconium sulfate, a catalyst with the characteristics of low cost, easy processing and low toxicity, is usually supported on various carriers in order to improve the catalyst properties. For example, zirconium
The surface diffusion of active species plays an important role in heterogeneous catalytic reactions [ 1 ], especially the diffusion of hydrogen species on the catalyst surface. Hydrogen molecules in the gaseous
Authors:Cleanio L. Lima, Hélvio S. A. de Sousa, Santiago J. S. Vasconcelos, Josué M. Filho, Alcemira C. Oliveira, Francisco F. de Sousa, and Alcineia C. Oliveira
Sulfatation is a well-known method for increasing the acidity of catalysts by improving their performance in catalytic reactions [ 1 – 8 ]. The promotion of oxides, such as Al 2 O 3, HfO 2 , ZrO 2 , TiO 2 , and Fe
(AlCl 3 , FeCl 3 , etc.) or strong mineral acids (e.g. HF) are used as catalysts for aromatic acylation. However, the use of conventional homogeneous catalysts is associated with a great number of drawbacks, since they are non-regenerable and usually