Cobalt Catalyst Reduction Thermodynamics in Fischer Tropsch: An Attainable Region Approach

A fundamental understanding of the precise reduction reaction pathway of cobalt-based catalysts is a crucial piece of knowledge in terms of the Fischer–Tropsch Synthesis (FTS) reaction. The use of hydrogen (H2) as the reduction agent results in a two-stage reduction of cobalt tetraoxide (Co3O4) to cobalt oxide (CoO) and then to metallic Co. The objective of the present work is to apply the Thermodynamic Attainable Region (TAR) to cobalt catalyst reduction using H2 so as to gain better insight regarding the thermodynamics of reduction reaction. TAR space diagrams suggest that complete Co3O4 reduction is feasible through two reaction pathways. Thus, the observed AR results suggest that the temperature programmed reduction’s (TPR) first reaction peak may be attributed to direct reduction of Co3O4 → Co and/or reduction to an intermediate compound Co3O4 → CoO. The second peak is a result of the reduction of either of the cobalt oxides to Co (Co3O4 → Co or CoO → Co).

Preparation of Mg-Sr Alloys Using Vacuum Reduction: A Thermodynamics Approach

At the present Mg-Sr alloy is usually produced by alloy mixing process or melt-leaching-reduction process which has low productivity. A new process has been developed termed “Preparation Mg-Sr alloys using vacuum thermal reduction”. The principle and procedure of the new process were discussed in this paper. The reduction thermodynamics was analyzed, including establishing the oxygen potential diagram of Sr, Mg, Si and Al, determination of main reactions, and evaluation of Gibbs free energy in vacuum. The results showed that Mg-Sr alloys can be obtained by synchronous reduction of SrO and MgO from a mixture of MgO, SrO, Si, CaO. The equipment, reduction temperature and vacuum for the new process have been also discussed.

Oxygen Chemistry

This book places oxygen on the center stage of chemistry in a manner that parallels the focus on carbon by 19th century chemists. One measure of the significance of oxygen chemistry is the greater diversity of oxygen-containing molecules than of carbon-containing molecules. One of the most important compounds is water, containing the properties of being a unique medium for biological chemistry and life, the source of all the dioxygen in the atmosphere, and the moderator of the earth's climate. Sawyer first introduces the biological origins of dioxygen and role of dioxygen in aerobic biology and oxidative metabolism, and in separate chapters discusses the oxidation-reduction thermodynamics of oxygen species, and the nature of the bonding for oxygen in its compounds. Additional chapters focus on the reactivities of specific oxygen compounds. The book will be of interest to chemists and biochemists, as well as graduate students, life scientists, and medical researchers.