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Although CBS catalyst 1 developed by Corey has become commonly employed in the CBS reduction reaction, other derivatives of the catalyst have been developed and utilized successfully. The R’ group of the CBS catalyst plays an important role in the enantioselectivity of the reduction, and as illustrated in above in the Scope section, several ...
Autocatalytic cycle of formose reaction showing how glyceraldehyde can be both the catalyst and the product of one portion of this complex reaction type. An early example of autocatalysis is the formose reaction, in which formaldehyde and base produce sugars and related polyols. Characteristic of autocatalysis, this reaction rate is extremely ...
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.
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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.
Polyphenol oxidase (PPO; also polyphenol oxidase i, chloroplastic), an enzyme involved in fruit browning, is a tetramer that contains four atoms of copper per molecule. [1] ...
Chloride is an ideal group due to the low cost of organochlorine compounds. Frequently, however, C–Cl bonds are too inert, and bromide or iodide leaving groups are required for acceptable rates. The main group metal in the organometallic partner usually is an electropositive element such as tin , zinc , silicon, or boron .
Common poisons include Group V, VI, and VII elements (e.g. S, O, P, Cl), some toxic metals (e.g. As, Pb), and adsorbing species with multiple bonds (e.g. CO, unsaturated hydrocarbons). [6] [22] For example, sulfur disrupts the production of methanol by poisoning the Cu/ZnO catalyst. [23] Substances that increase reaction rate are called promoters.