In the presence of iron (III) and other oxidants, HCl solutions of RhCl₃.3H₂O under mild conditions catalyze the oxidation of ethylene to acetaldehyde. The kinetics of the reaction measured by gas-uptake techniques indicate the presence of both ethylene dependent and independent steps. Hydroxy species such as RhCl₅(OH)³ ̄and RhCl₄(OH) (H₂O)² ̄, although present in very small concentrations, are significantly reactive towards ethylene. A mechanism based on that postulated for a similar Pd(II) system is presented. This involves the rearrangement of a rhodium (III) hydroxy π - ethylene complex to a σ - complex, followed by the production of acetaldehyde and rhodium (I). However, unlike in the Pd(II) system where the rate determining step is the conversion of the π - to σ-C₂H₄ complex, the rate determining step in the Rh(III) system is thought to involve the production of the π- complex. Iron (III) oxidizes Rh(I) back to Rh(III), giving the net reaction:
C₄H₄ + H₂O + 2Fe(III) Rh(III) ⇥ CH₃CHO + 2H+ + 2Fe(II) / Science, Faculty of / Chemistry, Department of / Graduate
| Identifer | oai:union.ndltd.org:UBC/oai:circle.library.ubc.ca:2429/34499 |
| Date | January 1970 |
| Creators | Kastner, Michael Robin |
| Publisher | University of British Columbia |
| Source Sets | University of British Columbia |
| Language | English |
| Detected Language | English |
| Type | Text, Thesis/Dissertation |
| Rights | For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use. |
Page generated in 0.0019 seconds