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The disadvantage with a copper catalysts is that it is very sensitive when it comes to sulfide poisoning, a future use of for example a cobalt- molybdenum catalyst could solve this problem. The catalyst mainly used in the industry today is a copper-zinc-alumina (Cu/ZnO/Al 2 O 3) based catalyst.
An illustrative example is the effect of catalysts to speed the decomposition of hydrogen peroxide into water and oxygen: . 2 H 2 O 2 → 2 H 2 O + O 2. This reaction proceeds because the reaction products are more stable than the starting compound, but this decomposition is so slow that hydrogen peroxide solutions are commercially available.
Most catalysts are given a finite service life due to known amounts of contaminants in the untreated gas. The most notable complication is the formation of ammonium sulfate and ammonium bisulfate from sulfur and sulfur compounds when high-sulfur fuels are used, as well as the undesirable catalyst-induced oxidation of SO 2 to SO 3 and H 2 SO 4 ...
Heterogeneous catalysts are typical in large-scale commercial processes, while homogeneous catalysts are used in finer laboratory chemical syntheses. [4] Organometallic catalysts used in ROMP usually have transition metal centres, such as tungsten, rubidium, titanium, etc., with organic ligands. [5]
Ziegler–Natta catalysts of the third class, non-metallocene catalysts, use a variety of complexes of various metals, ranging from scandium to lanthanoid and actinoid metals, and a large variety of ligands containing oxygen (O 2), nitrogen (N 2), phosphorus (P), and sulfur (S). The complexes are activated using MAO, as is done for metallocene ...
In industry, many design variables must be considered including reactor and catalyst design across multiple scales ranging from the subnanometer to tens of meters. The conventional heterogeneous catalysis reactors include batch , continuous , and fluidized-bed reactors , while more recent setups include fixed-bed, microchannel, and multi ...
The Houdry process at that time used reactors with a fixed bed of catalyst and was a semi-batch operation involving multiple reactors with some of the reactors in operation while other reactors were in various stages of regenerating the catalyst. Motor-driven valves were used to switch the reactors between online operation and offline ...
The production of the catalyst requires a particular melting process in which used raw materials must be free of catalyst poisons and the promoter aggregates must be evenly distributed in the magnetite melt. Rapid cooling of the magnetite, which has an initial temperature of about 3500 °C, produces the desired precursor.