Nickel-catalyzed isomerization of 2-methyl-3-butenenitrile to 3-pentenenitrile: A kinetic study using in situ FTIR-ATR spectroscopy

The isomerization of 2-methyl-3-butenenitrile (2M3BN) to 3-pentenenitrile (3PN) was followed using operando FTIR spectroscopy. The spectra were analyzed comprehensively to obtain kinetic profiles from the different band dynamics. Several spectral regions were transformed to their second derivative in order to improve the peak resolution. The dynamics in the spectra were calculated and normalized to the end conversion towards 3PN determined by GC. Similar kinetic profiles were obtained from the dynamics of different bands. Furthermore, calculations on the DFT level were performed for 2M3BN and trans- and cis-3PN in order to help identifying the corresponding bands in the spectra of the reaction mixture. An average conversion profile was calculated from different bands of the substrate and the product, applying a “quasi-multivariate analysis” technique to correlate different band dynamics. This approach was validated using advanced chemometrics. These profiles obtained by IR spectroscopic analysis for the formation of 3PN and the consumption of 2M3BN showed a zero order kinetic.