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Title: THE RADIATION-INDUCED POLYMERIZATION OF ISOBUTENE: A LIQUID PHASE IONIC REACTION

Abstract

New evidence is presented in support of the suggestion that the gamma - ray-induced polymerization of liquid isobutene at -78 deg C proceeds solely by a cationic mechanism. Attempts to polymerize isobutene at -78 deg C with free radicals from the photolysis of diacetyl, benzoin and benzil were unsuccessful but the benzil solution irradiated with ultraviolet light at 77 deg K was shown by electron spin resonance measurements to give rise to radicals from the isobutene. Isobutene irradiated in the pure state at a gamma -ray dose rate of 7 x 10/sup 17/ e.v. ml/sup -1/ min/sup -1/ polymerized with G(-C/sub 4/H/sub 8/) = 3.0 plus or minus 1.7 x 10/sup 2/. Solutions of FeCl/sub 3/, DPPH, benzoquinone and iodine in isobutene were also irradiated with gamma -rays. Of these solutes, only benzoquinone reduced the polymerization rate to zero, and DPPH had no significant effect. The effects of FeCl/sub 3/ and I/2 on the polymerization were complicated by other factors. The measured yields of conversion of the solutes after irradiation were G(-DPPH) =3.7 plus or minus 0.2, G(Fe(II)) = 3.0 plus or minus 0.5 and G(-Q) = 1.5 plus or minus 0.2. The electron spin resonance spectrum of isobutene irradiatedmore » with gamma -rays at 77 deg K showed the presence of H atoms which disappeared rapidly, and a more stable radical, the spectrum of which consisted of 6 peaks having an over-all spacing of 158 gauss at the operating frequency of 9400 Mc sec./sup -1/. The same six peak pattern was obtained from cyclopropane irradiated with gamma rays at 77 deg K and from a solution of benzil in isoDutene irradiated with ultraviolet light at 77 deg K. It is concluded that the radical responsible for this spectrum is either the cyclopropyl radical or the methyl substituted allyl radical, the latter being the less likely. The most likely initiating ion is considered to be (CH/sub 3/)/sub 3/C/sup +/, and a mechanism consistent with the available data is proposed. (auth)« less

Authors:
; ;
Publication Date:
Research Org.:
The University, Leeds, Eng.
Sponsoring Org.:
USDOE
OSTI Identifier:
4235513
NSA Number:
NSA-13-016058
Resource Type:
Journal Article
Journal Name:
Journal of Physical Chemistry (U.S.)
Additional Journal Information:
Journal Volume: Vol: 63; Other Information: Orig. Receipt Date: 31-DEC-59
Country of Publication:
Country unknown/Code not available
Language:
English
Subject:
CHEMISTRY; ATOMS; BENZENE; BUTYLENE; CATIONS; CHEMICAL REACTIONS; CONVERSION; CYCLOALKANES; DPPH; EFFICIENCY; ELECTRONS; FREE RADICALS; GAMMA RADIATION; HYDROGEN; INDUCTION; IODINE; IONS; IRON CHLORIDES; IRRADIATION; LIQUIDS; MEASURED VALUES; ORGANIC COMPOUNDS; ORGANIC NITROGEN COMPOUNDS; PHASE DIAGRAMS; PHOTOLYSIS; POLYMERIZATION; PROPANE; QUINONES; RADIATION DOSES; RADIATIONS; REDUCTION; RESONANCE; SOLUTIONS; SOLVENTS; SPECTRA; SPIN; TEMPERATURE; ULTRAVIOLET RADIATION

Citation Formats

Collinson, E., Dainton, F.S., and Gillis, H.A. THE RADIATION-INDUCED POLYMERIZATION OF ISOBUTENE: A LIQUID PHASE IONIC REACTION. Country unknown/Code not available: N. p., 1959. Web. doi:10.1021/j150576a033.
Collinson, E., Dainton, F.S., & Gillis, H.A. THE RADIATION-INDUCED POLYMERIZATION OF ISOBUTENE: A LIQUID PHASE IONIC REACTION. Country unknown/Code not available. doi:10.1021/j150576a033.
Collinson, E., Dainton, F.S., and Gillis, H.A. Mon . "THE RADIATION-INDUCED POLYMERIZATION OF ISOBUTENE: A LIQUID PHASE IONIC REACTION". Country unknown/Code not available. doi:10.1021/j150576a033.
@article{osti_4235513,
title = {THE RADIATION-INDUCED POLYMERIZATION OF ISOBUTENE: A LIQUID PHASE IONIC REACTION},
author = {Collinson, E. and Dainton, F.S. and Gillis, H.A.},
abstractNote = {New evidence is presented in support of the suggestion that the gamma - ray-induced polymerization of liquid isobutene at -78 deg C proceeds solely by a cationic mechanism. Attempts to polymerize isobutene at -78 deg C with free radicals from the photolysis of diacetyl, benzoin and benzil were unsuccessful but the benzil solution irradiated with ultraviolet light at 77 deg K was shown by electron spin resonance measurements to give rise to radicals from the isobutene. Isobutene irradiated in the pure state at a gamma -ray dose rate of 7 x 10/sup 17/ e.v. ml/sup -1/ min/sup -1/ polymerized with G(-C/sub 4/H/sub 8/) = 3.0 plus or minus 1.7 x 10/sup 2/. Solutions of FeCl/sub 3/, DPPH, benzoquinone and iodine in isobutene were also irradiated with gamma -rays. Of these solutes, only benzoquinone reduced the polymerization rate to zero, and DPPH had no significant effect. The effects of FeCl/sub 3/ and I/2 on the polymerization were complicated by other factors. The measured yields of conversion of the solutes after irradiation were G(-DPPH) =3.7 plus or minus 0.2, G(Fe(II)) = 3.0 plus or minus 0.5 and G(-Q) = 1.5 plus or minus 0.2. The electron spin resonance spectrum of isobutene irradiated with gamma -rays at 77 deg K showed the presence of H atoms which disappeared rapidly, and a more stable radical, the spectrum of which consisted of 6 peaks having an over-all spacing of 158 gauss at the operating frequency of 9400 Mc sec./sup -1/. The same six peak pattern was obtained from cyclopropane irradiated with gamma rays at 77 deg K and from a solution of benzil in isoDutene irradiated with ultraviolet light at 77 deg K. It is concluded that the radical responsible for this spectrum is either the cyclopropyl radical or the methyl substituted allyl radical, the latter being the less likely. The most likely initiating ion is considered to be (CH/sub 3/)/sub 3/C/sup +/, and a mechanism consistent with the available data is proposed. (auth)},
doi = {10.1021/j150576a033},
journal = {Journal of Physical Chemistry (U.S.)},
number = ,
volume = Vol: 63,
place = {Country unknown/Code not available},
year = {1959},
month = {6}
}