Gas-phase cationic benzoylation of ambient aromatic substrates studied with the decay technique

Journal Article · Wed Mar 05 00:00:00 EST 1986 · J. Am. Chem. Soc.; (United States)

DOI:https://doi.org/10.1021/ja00265a003· OSTI ID:5681550

Occhiucci, G; Cacace, F; Speranza, M

The gas-phase benzoylation of typical ambient aromatic substrates PhY (Y = OH, OMe, and NH/sub 2/) has been investigated by a combination of the decay technique and of FT ICR mass spectrometry. Labeled phenylium ions, C/sub 6/X/sub 5//sup +/ (X = H and T), from the decay of multiply tritiated benzene, C/sub 6/X/sub 6/, have been allowed to react with excess CO-containing traces of PhY (Y = OH, OMe, and NH/sub 2/), in the pressure range from 90 to 650 torr. Radio GLC and HPLC of the tritiated products demonstrate two competitive reaction channels, i.e., phenylation and benzoylation of the aromatic substrates. The results indicate a sharp kinetic bias of the gaseous phenylium ions for the aromatic substrates, measured by an apparent k/sub CO//k/sub PhY/ ratio of 0.12 (Y = OH), 0.13 (Y = OMe), and 0.04 (Y = NH/sub 2/) in the systems at nearly atmospheric pressure. Gas-phase benzoylation displays a high intramolecular selectivity, occurring exclusively at the n-type center of PhOH and PhNH/sub 2/. In the case of PhOMe, appreciable ring benzoylation is observed, characterized by a remarkably high (up to 30:1) bias for the para position. The mechanistic features of the gas-phase benzoylation and phenylation processes, deduced from the decay and the ICR experiments, are discussed and compared with those of related aromatic acylation and alkylation reactions occurring in the dilute gas state. 30 references, 2 tables.

• Research Organization: Istituto di Chemica Nucleare del C.N.R., Roma, Italy
• OSTI ID: 5681550
• Journal Information: J. Am. Chem. Soc.; (United States), Vol. 108:5
• Country of Publication: United States
• Language: English

Related Subjects

38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEAR CHEMISTRY
AROMATICS
BENZOYLATION
TRITIUM COMPOUNDS
CATIONS
CHEMICAL REACTION KINETICS
EXPERIMENTAL DATA
GASES
MASS SPECTROSCOPY
RADIOCHROMATOGRAPHY
REACTION INTERMEDIATES
ACYLATION
CHARGED PARTICLES
CHEMICAL REACTIONS
CHROMATOGRAPHY
DATA
FLUIDS
INFORMATION
IONS
KINETICS
LABELLED COMPOUNDS
NUMERICAL DATA
ORGANIC COMPOUNDS
REACTION KINETICS
SEPARATION PROCESSES
SPECTROSCOPY
400701* - Radiochemistry & Nuclear Chemistry- Hot-Atom Chemistry