摘要:

The techniques and some preliminary results of an indirect method of studying vapor phase radiolysis by electron spin resonance (e.s.r.) spectroscopy are reported. After traversing a beam of 40 keV Ar+ions, a stream of vapor is condensed on a cold finger at 77 °K. Free radicals which are formed by ion bombardment in the vapor phase become trapped in the solid deposit and are detected by e.s.r. Various vapors such as cyclopentane, cyclohexane, benzene, and ethanol have been bombarded at room temperature. The results correlate with conventional radiation chemical data. For example, benzene forms(and probably) radicals. These may be the intermediates which lead to polymer formation when benzene vapor is irradiated. The potential value of the experiment to vapor phase radiation chemistry is discussed.

ISSN:0008-4042    

DOI:10.1139/v67-130

出版商:NRC Research Press    

年代:1967

数据来源: NRC

摘要:

The hydroperoxy radical (HOO·) is the main chain propagating and terminating radical in the autoxidation of dilute solutions of 1,4-cyclohexadiene and 1,4-dihydronaphthalene in chlorobenzene at 30 °C. The absolute rate constant for the self-reaction of hydroperoxy radicals (chain termination) in nonpolar solvents is very much higher than previously reported values in aqueous media.

ISSN:0008-4042    

DOI:10.1139/v67-131

出版商:NRC Research Press    

年代:1967

数据来源: NRC

摘要:

Absolute rate constants have been measured for the autoxidation of a large number of hydrocarbons at 30 °C. The chain-propagating and chain-terminating rate constants depend on the structure of the hydrocarbon and also on the structure of the chain-carrying peroxy radical. With certain notable exceptions which are mainly due to steric hindrance, the rate constants for hydrogen-atom abstraction increase in the order primary < secondary < tertiary; and, for compounds losing a secondary hydrogen atom, the rate constants increase in the order unactivated < acyclic activated by a single π-electron system < cyclic activated by a single Π-system < acyclic activated by two π-systems < cyclic activated by two π-systems. The rate constants for chain termination by the self-reaction of two peroxy radicals generally increase in the order tertiary peroxy radicals < acyclic allylic secondary  cyclic secondary  acyclic benzylic secondary < primary peroxy radicals < hydroperoxy radicals.

ISSN:0008-4042    

DOI:10.1139/v67-132

出版商:NRC Research Press    

年代:1967

数据来源: NRC

摘要:

The equilibrium diagrams of the systems Li2SO4–LiBrO3–H2O and NaBrO3–LiBrO3–H2O have been determined at 25°. The system NaBrO3–LiBrO3–H2O is simple, neither compound nor solid solution being formed. In both systems the stable solid form of lithium bromate is the monohydrate and the X-ray powder picture of this monohydrate has been obtained.In the system Li2SO4–LiBrO3–H2O, a solid solution of LiBrO3.H2O in Li2SO4.H2O, having the Li2SO4.H2O lattice, extends from Li2SO4.H2O up to a solid solution of composition 42 wt.% Li2SO4, 45 wt.% LiBrO3, 13 wt.% H2O. No corresponding solid solution of Li2SO4.H2O in LiBrO3.H2O exists. No intermediate phase corresponding to a stoichiometric compound, or at least to another lattice pattern, exists.

ISSN:0008-4042    

DOI:10.1139/v67-133

出版商:NRC Research Press    

年代:1967

数据来源: NRC

摘要:

This paper describes the observation and measurement of a strong absorption at 6 330 Å by a species produced very close to a polished silver cathode in the electrolysis of aqueous solutions. The species is likely to be the hydrated electron, thus corroborating some earlier chemical evidence. The technique involves directing a laser beam along a long, curved, polished, silver electrode surface and measuring very small changes in light transmission by modulating the electrolytic current at a frequency to which the detector's amplifier has been tuned.

ISSN:0008-4042    

DOI:10.1139/v67-134

出版商:NRC Research Press    

年代:1967

数据来源: NRC

摘要:

The thermal properties of the binary systems AgCl–KCl, AgCl–RbCl, and AgCl–CsCl have been investigated over the entire composition range and in the temperature range 660 to 860 °C. From the combined results of the calorimetric investigation and the measured phase diagrams of the binary systems, activities and other partial molar properties have been calculated.

ISSN:0008-4042    

DOI:10.1139/v67-135

出版商:NRC Research Press    

年代:1967

数据来源: NRC

摘要:

The system H2O–NaCl–MgSO4was studied by both the isopiestic and the electromotive force (e.m.f.) methods, and mean activity coefficients of NaCl and MgSO4were measured at 25 °C at ionic strengths up to 0.72. Difficulty was encountered in extrapolating the isopiestic results to infinite dilution and an extrapolation was chosen which made the isopiestic results consistent with e.m.f. results on the same system. Harned's rule was not obeyed for either salt.

ISSN:0008-4042    

DOI:10.1139/v67-136

出版商:NRC Research Press    

年代:1967

数据来源: NRC

摘要:

The hydroxo-complexes of silver and zinc are determined from a plot of their hydroxide solubility curves vs. pH, at 25 °C and unit ionic strength (NaClO4). The hydroxide solubility products and the formation constants of AgOH, Ag(OH)2−, ZnOH+, Zn(OH)2, Zn(OH)3−, and Zn(OH)42−are calculated.

ISSN:0008-4042    

DOI:10.1139/v67-137

出版商:NRC Research Press    

年代:1967

数据来源: NRC

摘要:

Electron spin resonance (e.s.r.) methods have been used to search for theγ-ray-induced formation of trapped electrons and free radicals in 13 straight-chain and branched-chain terminal olefins at 77 °K. When e.s.r. spectra were observed they were used to identify the species present. Changes induced by subsequent exposure to visible and ultraviolet (u.v.) light were investigated. Trapped electrons were observed in three olefins that exist as glasses at 77 °K, hexene-1, hexene-2, and 2-methylbutene-1, but were not detected in two other glassy olefins, possibly because of rapid annealing. No trapped electrons were found in polycrystalline olefins at 77 °K. The possibility that CO2−ions have been misinterpreted as trapped electrons in these and other systems is discussed and eliminated. The formation and behavior of free radicals and trapped electrons in irradiated 2-methylbutene-1 are analogous to those previously reported for 2-methylpentene-1 under similar conditions. These observations support the hypothesis that in these two systems ions produced initially isomerize rapidly, leading to the formation of the free radicals detected by e.s.r. The results of a subsidiary experiment suggest that hydrogen abstraction from the matrix is induced by u.v. photolysis of the radicals present in 2-methylpentene-1.

ISSN:0008-4042    

DOI:10.1139/v67-138

出版商:NRC Research Press    

年代:1967

数据来源: NRC

摘要:

γ-Irradiated sulfuric acid glasses have been studied at low temperatures by optical spectrophotometry and electron spin resonance (e.s.r.) spectrometry. The effects of nitrous oxide and ferrous ion on the spectra were observed. Optical absorptions were found with maxima at 22 000 and 32 000 cm−1in the pure glass and at 41 000 cm−1in the presence of ferrous ion, as well as two e.s.r. absorptions. These were a poorly resolved triplet and a narrow singlet. The spectra, and the changes observed on warming, suggest the presence of three species in the glass: a free radical similar to the radical ion SO4−, a ferric ion precursor, and a third unidentified species formed with a small yield.

ISSN:0008-4042    

DOI:10.1139/v67-139

出版商:NRC Research Press    

年代:1967

数据来源: NRC