Dissociative photoionization of methyl crotonate: experimental and theoretical insights

doi:10.7523/j.issn.2095-6134.2021.02.007

Abstract

Abstract: The photoionization and dissociation of methyl crotonate have been studied by tunable vacuum ultraviolet synchrotron radiation coupled with time-of-flight mass spectrometer in the photon energy region 9.0-14.5 eV. The ionization energy of methyl crotonate and the appearance energies for major fragments C₄H₅O₂⁺, C₄H₅O⁺,C₄H₄O⁺, C₂H₃O₂⁺, C₃H₅⁺, and C₂H₅⁺ are determined to be 10.11, 10.73, 10.88, 12.2, 11.93(12.77), and 12.44 eV, respectively, according to the photoionization efficiency curves. Based on the experimental AEs and energies predicted by ab initio G3B3 calculations, possible formation channels for the major fragments C₄H₅O₂⁺+CH₃, C₄H₅O⁺+CH₃O, C₄H₄O⁺+CH₄O, C₂H₃O₂⁺+C₃H₅, C₃H₅⁺+C₂H₃O₂(CO+CH₃O), and C₂H₅⁺+C₃H₃O₂ are proposed. Transition states and intermediates involved in the dissociation channels are also located. The majority of the proposed channels occur through isomerization processes prior to dissociations. Hydrogen shift and ring closing/opening are found to be the dominant processes during photoionization and dissociation of methyl crotonate.

Key words: methyl crotonate, synchrotron radiation, mass spectrometry, dissociative photoionization, G3B3 calculations

CLC Number:

O641

SUN Ruirui, LI Yanbo, CHEN Jun, MENG Qinghui, WANG Huanhuan, ZHANG Hang, SHAN Xiaobin, LIU Fuyi, SHENG Liusi. Dissociative photoionization of methyl crotonate: experimental and theoretical insights[J]. Journal of University of Chinese Academy of Sciences, 2021, 38(2): 207-216.

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