Gas-phase measurements of the kinetics of BF2+-induced polymerization of olefinic monomers

The initial steps in the BF2+-induced polymerization of the monomers of ethylene, propylene, cis-2-butene, isobutene, and styrene have been observed in the gas phase at room temperature using the Selected-Ion Flow Tube (SIFT) technique. Rate constants and product distributions have been determined for the initiation of the polymerization in each case. All five initiation reactions were found to be rapid (k ≥ 5.0 × 10−10 cm3 molecule−1 s−1). The primary product ions that propagate polymerization have been identified and sequential addition reactions have been followed in all five systems. For ethylene the energetics of the initial steps have been followed using abinitio molecular orbital theory. Reactions of BF2+ with the vapours of water and benzene have also been characterized. Keywords: ion-induced polymerization, alkenes, kinetics, gas phase ion chemistry.

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Understanding Gas Phase Ion Chemistry Is the Key to Reliable Selected Ion Flow Tube-Mass Spectrometry Analyses

Analytical Chemistry ◽

10.1021/acs.analchem.0c03050 ◽

2020 ◽

Vol 92 (19) ◽

pp. 12750-12762 ◽

Cited By ~ 3

Author(s):

David Smith ◽

Murray J. McEwan ◽

Patrik Španěl

Keyword(s):

Mass Spectrometry ◽

Gas Phase ◽

Ion Chemistry ◽

Flow Tube ◽

Ion Flow ◽

Gas Phase Ion Chemistry ◽

Selected Ion Flow Tube ◽

Gas Phase Ion

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Carbocationic polymerization in the gas phase: polymerization of acetylene induced by BF2+

Canadian Journal of Chemistry ◽

10.1139/v90-252 ◽

1990 ◽

Vol 68 (9) ◽

pp. 1629-1635 ◽

Cited By ~ 7

Author(s):

Leonard Forte ◽

Min H. Lien ◽

Alan C. Hopkinson ◽

Diethard K. Bohme

Keyword(s):

Gas Phase ◽

Molecular Orbital Theory ◽

Primary Reaction ◽

Orbital Theory ◽

Flow Tube ◽

Phase Measurements ◽

Ion Flow ◽

Kinetic Information ◽

Selected Ion Flow Tube ◽

Sequential Addition

Gas-phase measurements for the primary reaction of BF2+ with acetylene and the ensuing higher-order reactions with acetylene have been performed at 296 ± 2 K in helium at 0.35 torr using the Selected-Ion Flow Tube (SIFT) technique. The primary reaction was observed to be rapid and to produce two species which both initiated rapid polymerization of acetylene. The major primary product, C2HBF+, was observed to initiate the sequential addition of four molecules of acetylene, most likely by termolecular association reactions. The first few steps in this polymerization were also followed using abinitio molecular orbital theory. The calculations and measurements provide structural, energetic, and kinetic information and, in combination, reveal several intrinsic features of the initial steps of the cationic polymerization of acetylene initiated by BF2+. Keywords: polymerization, acetylene, aromaticity.

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