Insight into the mechanism of acetonitrile hydrogenation in liquid phase on Pt/Al2O3 by ATR-FTIR

[Display omitted] •A Flow-through cell-microreactor in Attenuated Total Reflection (ATR) mode was used.•Hydrogenation of acetonitrile to amines over a platinum catalyst.•Imine surface intermediate (CH3CH = NH) was identified.•A microkinetic mechanism was proposed and kinetic constants were obtained....

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Bibliographic Details
Published in:Catalysis today 2019-10, Vol.336, p.22-32
Main Authors: Aguirre, Alejo, Collins, Sebastián E.
Format: Article
Language:English
Subjects:
Amines
Attenuated total reflection
Nitrile hydrogenation
Platinum
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Summary:[Display omitted] •A Flow-through cell-microreactor in Attenuated Total Reflection (ATR) mode was used.•Hydrogenation of acetonitrile to amines over a platinum catalyst.•Imine surface intermediate (CH3CH = NH) was identified.•A microkinetic mechanism was proposed and kinetic constants were obtained. The mechanism of the acetonitrile hydrogenation to amines over a platinum/alumina catalyst was investigated by in situ infrared spectroscopy. The reaction was studied under realistic conditions -liquid phase using toluene as solvent- using a flow-through cell-microreactor in Attenuated Total Reflection (ATR) mode. Acetonitrile linearly chemisorbed on platinum sites is stepwise hydrogenated to form an imine surface intermediate (CH3CH = NH), which in turn is hydrogenated to ethylamine. Using deuterium, the sequential formation of CD and ND bonds was observed. Then, imine intermediate can condense producing diethylamine and triethylamine, giving ammonia as a by-product. The temporal evolution of the IR signals was modeled using a proposed microkinetic mechanism and intrinsic kinetic constants were obtained under chemical control.
ISSN:0920-5861
1873-4308
DOI:10.1016/j.cattod.2019.04.027