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The first step in the WGS reaction is the high temperature shift which is carried out at temperatures between 320 °C and 450 °C. As mentioned before, the catalyst is a composition of iron-oxide, Fe 2 O 3 (90-95%), and chromium oxides Cr 2 O 3 (5-10%) which have an ideal activity and selectivity at these temperatures.
FCC units continuously withdraw and replace some of the catalyst in order to maintain a steady level of activity. Modern FCC catalysts are fine powders with a bulk density of 0.80 to 0.96 g/cm 3 and having a particle size distribution ranging from 10 to 150 μm and an average particle size of 60 to 100 μm.
In marine applications, this can increase fresh water requirements as the boiler must be continuously washed to remove the deposits. Most catalysts on the market have porous structures and a geometries optimized for increasing their specific surface area (a clay planting pot is a good example of what SCR catalyst feels like). This porosity is ...
Aliquat 336 is used as a phase transfer catalyst, [2] including in the catalytic oxidation of cyclohexene to 1,6-hexanedioic acid. [3] This reaction is an example of green chemistry, as it is more environmentally friendly than the traditional method of oxidizing cyclohexanol or cyclohexanone with nitric acid or potassium permanganate, which produce hazardous wastes.
The resulting catalyst particles consist of a core of magnetite, encased in a shell of wüstite, which in turn is surrounded by an outer shell of metallic iron. The catalyst maintains most of its bulk volume during the reduction, resulting in a highly porous high-surface-area material, which enhances its catalytic effectiveness.
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.
A slurry reactor contains the catalyst in a powdered or granular form. [7] This reactor is typically used when one reactant is a gas and the other a liquid while the catalyst is a solid. The reactant gas is put through the liquid and dissolved. It then diffuses onto the catalyst surface.
The Monsanto process is an industrial method for the manufacture of acetic acid by catalytic carbonylation of methanol. [1] The Monsanto process has largely been supplanted by the Cativa process, a similar iridium-based process developed by BP Chemicals Ltd, which is more economical and environmentally friendly.