The heats of formation of some C[sub 2]H[sub 5]O[sup +] isomers, relevant bond energies in ethanol and PA(CH[sub 3]CHO)

Journal Article · Thu Dec 15 04:00:00 EST 1994 · Journal of Chemical Physics; (United States)

DOI:https://doi.org/10.1063/1.467843· OSTI ID:7177619

Ruscic, B; Berkowitz, J ^[1]

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1. Chemistry Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States)

The ionization potentials of the transient species CH[sub 3]CH[sub 2]O, CH[sub 3]CHOH, and CH[sub 2]CH[sub 2]OH (generated by the F+ethanol reactions) are measured by photoionization mass spectrometry: I.P.(CD[sub 3]CD[sub 2]O)=10.29[plus minus]0.08 eV (tentative), I.P.(CH[sub 3]CHOH)[lt]6.85 eV, and I.P.(CD[sub 2]CH[sub 2]OH) [le]8.35[plus minus]0.06 eV. The latter results in a cation of uncertain structure. These reactions also generate vinyl alcohol (adiabatic I.P.=9.33[plus minus]0.01 eV) and acetaldehyde. A redetermined appearance potential of CH[sub 3]CHOH[sup +] from ethanol enables one to infer the proton affinity of acetaldehyde to be [ge]183.8[plus minus]0.2 kcal/mol and an [alpha] (C--H) bond energy in ethanol [gt]91.1 kcal/mol (0 K). The appearance potential of [ital m]/[ital e]=45 ion from bromoethanol is interpreted as formation of a C[sub 2]H[sub 5]O[sup +] isomer having the oxirane structure, with [Delta][ital H][sub [ital f][sub 0]][sup 0] of [similar to]173.9 kcal/mol, consistent with earlier alternative measurements. A second increase in the [ital m]/[ital e]=45 ion yield curve from ethanol is interpreted as formation of this same isomer. This interpretation, and an alternative cycle, lead to a [beta] (C--H) bond energy in ethanol of 98[plus minus]2 kcal/mol. The implication of the current results to the dynamics of dissociation of ethanol cations is discussed. [copyright] [ital 1994][ital American] [ital Institute] [ital of] [ital Physics].

• Research Organization: Argonne National Laboratory (ANL), Argonne, IL
• DOE Contract Number: W-31109-ENG-38
• OSTI ID: 7177619
• Journal Information: Journal of Chemical Physics; (United States), Journal Name: Journal of Chemical Physics; (United States) Vol. 101:12; ISSN JCPSA6; ISSN 0021-9606
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400500* -- Photochemistry
ACETALDEHYDE
ALCOHOLS
ALDEHYDES
ALKOXY RADICALS
ALKYL RADICALS
BINDING ENERGY
CATIONS
CHALCOGENIDES
CHARGED PARTICLES
CHEMICAL REACTIONS
ELEMENTS
ENERGY
ENTHALPY
ETHANOL
ETHOXY RADICALS
FLUORINE
FORMATION HEAT
HALOGENS
HYDROXY COMPOUNDS
IONIZATION
IONIZATION POTENTIAL
IONS
ISOMERS
MASS SPECTROSCOPY
NONMETALS
ORGANIC COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
PHOTOIONIZATION
PHYSICAL PROPERTIES
RADICALS
REACTION HEAT
SPECTROSCOPY
THERMODYNAMIC PROPERTIES
VINYL RADICALS