Non-equilibrium Effects in the Hydrogenation-mediated Isomerization Mechanism of Olefins during Cavitating Ultrasound Processing
The process whereby cis-olefins isomerize to their trans form is generally understood as occurring through C-H activation of surface bound alkyl radical species. Here we present aqueous phase deuteration results of cis-2-buten-1-ol on Raney Nickel. In the context of the accepted olefin isomerization mechanism, our results illustrate that transition-state theory can accurately model the competition between C-H and C-D activation for olefin exchange (isomerization) for the case of conventional catalytic processing. This is the case also for a catalytic process that includes cavitating ultrasound, although the model then requires a much higher vibrational temperature (at least ~800 K) in order to simulate the selectivity of the deuterium exchange process. Thus, cavitating ultrasound likely incorporates a high level of molecular vibrational excitation, suggesting that the vibrational temperature is not in equilibrium with the thermal (e.g., translational) temperature as the chemistry proceeds along a traditional reaction path.
- Research Organization:
- Pacific Northwest National Lab. (PNNL), Richland, WA (United States). Environmental Molecular Sciences Lab. (EMSL)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AC05-76RL01830
- OSTI ID:
- 883202
- Report Number(s):
- PNNL-SA-45075; 6502b; TRN: US200621%%773
- Journal Information:
- Catalysis Communications, 7(6):348–350, Journal Name: Catalysis Communications, 7(6):348–350
- Country of Publication:
- United States
- Language:
- English
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