THE RADIATION CHEMISTRY OF $beta$-PINENE

Journal Article · Tue May 01 04:00:00 EDT 1962 · Journal of the Chemical Society (England) Divided into J. Chem. Soc. A, J. Chem. Soc. B, etc.

DOI:https://doi.org/10.1039/jr9620001531· OSTI ID:4816495

Bates, T H; Best, J V.F.; Williams, T F

On irradiation with Co/sup 60/ gamma rays, dry BETA -pinene polymerizes in vacuo, to give a product which is partially precipitated from the liquid monomer. The kinetics of the reaction were followed by using dilatometers. At 25--30 deg with a constant dose rate (2.55 x 10/sup 17/ ev g/sup -1/ min-1), polymer formation is linear with time of irradiation up to 60% conversion and the mean yield corresponds to the polymerization of 850 monomer molecules per 100 ev. A decrease in dose rate results in a higher yield per unit dose. The rate shows a positive temperature coefficient in the range -35 to + 55 deg . The polymers are formed with a range of molecular weights and a number-average value of 1360 is obtained for the chloroform-soluble fraction; the insoluble polymer is of higher molecular weight and melts at 220 deg . Infrared and nuclear magnetic resonance spectra together with the determination of iodine values indicate the presence of unsaturated groups in the polymer structure. The polymerization yield is sensitive to the drying technique employed for the monomer and the rate of a dry reaction is strongly retarded by added water although the molecular weight of the resultant polymer is unaffected. Evidence of initiator transfer to monomer during the dry polymerization, as well as the marked effect of water, strongly support the participation of ions in the mechanism. A concurrent isomerization of BETA -pinene to dipentene ensues during the polymerization with a yield of 12 molecules per 100 ev; other isomers are also formed in comparable yields. (auth)

• Research Organization: Atomic Energy Research Establishment, Harwell, Berks, Eng.
• NSA Number: NSA-16-020498
• OSTI ID: 4816495
• Journal Information: Journal of the Chemical Society (England) Divided into J. Chem. Soc. A, J. Chem. Soc. B, etc., Journal Name: Journal of the Chemical Society (England) Divided into J. Chem. Soc. A, J. Chem. Soc. B, etc.; ISSN JCSOA
• Country of Publication: Country unknown/Code not available
• Language: English

Related Subjects

ALKENES
CATALYSIS
CHEMISTRY
CHLOROFORM
COBALT 60
CONFIGURATION
EVAPORATION
EXPANSION
GAMMA SOURCES
HYDROCARBONS
INFRARED RADIATION
IODINE
IRRADIATION
ISOMERS
LABORATORY EQUIPMENT
MEASURED VALUES
NUCLEAR MAGNETIC RESONANCE
ORGANIC CHLORINE COMPOUNDS
POLYMERIZATION
POLYMERS
RADIATION CHEMISTRY
RADIATION DOSES
REACTION KINETICS
SOLUTIONS
SPECTRA
TEMPERATURE
TERPENES
VACUUM
WATER