Kinetic models for catalytic selection processes as applied to asymmetric hydrogenation

✍ Scribed by Detlef Heller; Richard Thede; Detlef Haberland

• Publisher: Elsevier Science
• Year: 1997
• Tongue: English
• Weight: 748 KB
• Volume: 115
• Category: Article
• ISSN: 1381-1169
• DOI: 10.1016/s1381-1169(96)00341-x

✦ Synopsis

Kinetic terms for product formation in selection processes are evaluated for the example of asymmetric hydrogenation. The investigated models are characterized by preceding intermolecular equilibria to 2-4 stereoisomeric substrate complexes as well as direct intramolecular interconversion between corresponding diastereomeric intermediates. In the case of isobaric conditions the gross-hydrogen consumption can be described in each case by an equation analogous to simple Michaelis-Menten-type kinetics. The interpretation of the resulting constants is briefly demonstrated for a few practical examples. The temperature dependence of the enantiomeric ratio for the resulting products, as for example for a selection process. is also considered for the investigated models. Ke~~~~rt/.rt Asymmetric hydrogenation; Rhodium; Temperature dependence: Isoinversion principle Corresponding author.

' Selectivity as used in this context is the ratio of the rate of formation of a favoured product and the sum of the formation rates of all products [I].