Radiation Chemistry of Organic Compounds. IV. Cyclohexane

Dewhurst, H. A.

doi:10.1021/j150576a009

Cited by 40 publications

(15 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The naphthenes have, with the exception of cyclohexane, 12 received very little detailed investigation with respect to their behaviour when subjected to ionising radiation. The available data are summarised in Table 2.…”

Section: Naphthenic Hydrocarbonsmentioning

confidence: 99%

Ionisation and irradiation effects in high-voltage dielectric materials

Black¹,

Reynolds²

1965

Proc. Inst. Electr. Eng. UK

View full text Add to dashboard Cite

SynopsisA study of the chemical changes produced by exposure of dielectric materials to high-energy ionising radiation has shown that the effects are similar to those involved in electrical deterioration during stress aging and when ionisation has taken place in the dielectric. The principal effects observed in hydrocarbons and polymeric materials after exposure to radiation are: the crosslinking of the molecules to form an infusible gel structure; the evolution of hydrogen and low-molecular-weight fragments; molecular degradation by main-chain scission; the formation and annihilation of unsaturated groups; and, in the presence of air, processes of oxidative degradation. The corresponding electric stress and ionisation phenomena are: wax or 'cheese' formation in solid-type cables; the gas evolving characteristics of paraffinic oils; the embrittlement of insulating paper; the formation of double bonds in aged cable oils, as evidenced by increased absorption in the ultraviolet region; and the oxidation effects with air resulting in an increase in power factor.While the mechanisms of radiation-induced change are not yet completely understood, they should throw light on the corresponding electrical stress and ionisation phenomena. Some of the methods used to protect organic systems against the effects of high-energy radiation are also satisfactory in reducing electrical effects, and a study of these protective mechanisms should be beneficial in the field of high-voltage dielectrics.

show abstract

Section: Naphthenic Hydrocarbonsmentioning

confidence: 99%

Ionisation and irradiation effects in high-voltage dielectric materials

Black¹,

Reynolds²

1965

Proc. Inst. Electr. Eng. UK

View full text Add to dashboard Cite

show abstract

“…Oiie activated species, c-CsHlo*, decomposes to produce "cold" I~).drogen atoms (reaction [ 2 * ] ) , while the other activated species, c-CsHlo**, decoinposes to produce "hot" hj.drogen atoms (reaction [2**]). I t is further postulated that the hot hydrogen atoms abstract from cyclohexene according t o reaction [3] and t h a t most of the cold hyclrogen atoms add t o cyclohexene according t o reaction [4]. T h e possibility t h a t c-CGH1?"…”

Section: Notementioning

confidence: 99%

“…In pure cyclohexeile G(H2) = 1.2 and the only reactions that enter illto the productioil of hydrogen in this system are reactions [I**], [2**], and [3]. I t may therefore be assumed that the amount of hydrogen resultiilg from the direct excitation of cyclohexene, G(H2)**, is given by This hydrogen cannot be scavenged by cyclohexe~le but G(H2)" inay be decreased by energy transfer from c-C6H12" to cyclohexene, provided that all the excited cyclohexene molecules, c-C6Hlo***, SO [3] enter into the production of hydrogen froin this source.…”

Section: Cyclo1zexa-lte-cyclolzexe?ze Solutionsmentioning

confidence: 99%

“…I t may therefore be assumed that the amount of hydrogen resultiilg from the direct excitation of cyclohexene, G(H2)**, is given by This hydrogen cannot be scavenged by cyclohexe~le but G(H2)" inay be decreased by energy transfer from c-C6H12" to cyclohexene, provided that all the excited cyclohexene molecules, c-C6Hlo***, SO [3] enter into the production of hydrogen froin this source. Steady-state treatment of these reactions gives which may be rearranged to where y = x k16/k14", x = fraction of c-C6Hlo*** that deco~nposes to forin hot hydrogen atoms and hence inolecular hydrogen, and R" represents the left-hand side of equation [vii].…”

Section: Cyclo1zexa-lte-cyclolzexe?ze Solutionsmentioning

confidence: 99%

See 1 more Smart Citation

The Radiolysis of Cyclohexane: Ii. Cyclohexane–cyclohexene Solutions and Pure Cyclohexene

Freeman¹

1960

Can. J. Chem.

View full text Add to dashboard Cite

The γ-radiolysis of cyclohexane–cyclohexene solutions and of pure cyclohexene has been investigated. The previously determined yields of the two activated species in irradiated cyclohexane have been confirmed. G(c-C6H12′′) = 3.0 ± 0.3 and G(c-C6H12′) = 2.4 ± 0.3.The yields of the main products of cyclohexene radiolysis are G(H2) = 1.2, G(c-C6H12) = 1.0, G[(c-C6H9)2] = 1.4, and G(c-C6H10 → higher polymer) ≈ 4. There were smaller amounts of ethylene, acetylene, a C4 hydrocarbon (probably butadiene), cyclohexylcyclohexene, and dicyclohexyl.For the reactions[Formula: see text]and[Formula: see text]the value k7a/(k8ak6a)1/2 = 0.45 ± 0.08 was determined.The reaction mechanism that occurs during the radiolysis of cyclohexane–cyclohexene solutions is similar to that which occurs during the radiolysis of cyclohexane–benzene solutions (Part I of this series) with the additional consideration that cyclohexene itself is considerably decomposed during the radiolysis.

show abstract

“…(Linear Energy Transfer)* of the irradiation. Dewhurst (2) showed that G(cyc1ohexene) decreases with dose (i.e. with increasing cyclohexene concentration) and, further, that in concentrated solution (5 X lo-.'…”

Section: Introductionmentioning

confidence: 98%

Radiation Chemistry of Cyclohexane: Ii. Dose Rate Effects on the Formation and Destruction of Cyclohexene

Dyne¹,

Fletcher²

1960

Can. J. Chem.

View full text Add to dashboard Cite

Prolonged radiolysis of cyclohesaile leads to a steady-state concentration of cyclohexene where G(cyc1ohexene) = 0. At concentrations greater than this steady concentration, cyclohexene is destroyed. I t is shown that this steady-state concentration is a function of dose rate, varying approxin~ately as the fourth root of the radiation intensity. . A discussion of these and other observations indicates that dose rate and L.E.T. effects are observed in cyclohexane onIy if radical scavengers are present and that cycIohesene, a product of radiolysis, acts as a radical scavenger in irradiated cyclohexane. INTRODUCTIONCyclohexeile and bicyclohexyl are the two major high lnolecular weight products formed in the radiolysis of cyclohexane. Dewhurst and Schuler (1) have shown that the initial G values (molecules formed/100 ev absorbed) for cyclohexene and bicyclohexyl are independent of the L.E.T. (Linear Energy Transfer)* of the irradiation. Dewhurst (2) showed that G(cyc1ohexene) decreases with dose (i.e. with increasing cyclohexene concentration) and, further, that in concentrated solution (5 X lo-.' moles/g), cyclohexene is destroyed. I t follows that prolonged irradiation of cyclohexane or of solutions of cyclohexene in cyclohexane leads to a "steady-state" concentration of cyclohexene where G(cyc1ohexene) = 0. Dewhurst and Schuler (1) found some evidence that G(cyc1ohexene) fell off more rapidly with cyclohexeile concentration a t low dose rates, using a CoGO y-ray source, than a t the higher dose rates obtained with electron and particle beams.We have studied the formation and destruction of cyclohexene as a function of the dose rate, using CoGO y-rays and have shown that the "steady-state" concentration increases slowly with the dose rate. The dependence is less than a proportionality to the square root of radiation intensity and approximates to a fourth root dependence. E X P E R I M E N T A LSamples of cyclohexane (spectroscopic grade from various manufacturers) were irradiated in sealed glass vessels. The liquids were degassed by freezing, pumping, and thawing five times. Two CoGO sources were used (3) having dose rates of 1.4 X 1019 ev/g hr and 9.6X1017 ev/g hr. These dose rates were established using the Friclie dosimeter, G(Fe3+) = 15.5 ions/100 ev. Analysis for cyclohexeile was done by infrared spectrophotometry of the 640 cm-I band of cyclohexene using a Perltin-Elmer, model 21, spectrometer. Path lengths of 0.2-4.0 nlm were used with con~pensating cells containing pure cyclohexane for the thicker cells. The irradiations were made over an extended period of time (irradiations of up to 1400 hours a t the low dose rate). The solutions were stored after irradiation and were all analyzed a t one time together with a series of standard solutions of known concentration. The concentrations were determined by graphical interpolation from the measurements of the standard spectra. At the low 'Manuscript

show abstract

Radiation Chemistry of Organic Compounds. IV. Cyclohexane

Cited by 40 publications

References 0 publications

Ionisation and irradiation effects in high-voltage dielectric materials

Ionisation and irradiation effects in high-voltage dielectric materials

The Radiolysis of Cyclohexane: Ii. Cyclohexane–cyclohexene Solutions and Pure Cyclohexene

Radiation Chemistry of Cyclohexane: Ii. Dose Rate Effects on the Formation and Destruction of Cyclohexene

Contact Info

Product

Resources

About