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Item Pulse Radiolytic Oxidation of Chloral Hydrate in Oxygenated and Deoxygenated Aqueous Solutions(Journal of the Chemical Society : Faraday Transaction - I. The Chemical Society, London. 1973, 69 (2), 1973) Eriksen, T.; Henglein, A.; Stockhausen, K.Dilute chloral hydrate solutions containing either N2O or a N2O + O2 mixture were pulse irradiated and their optical absorption and electrical conductivity simultaneously recorded as functions of time. The first product of OH and H attack on chloral hydrate is the CCl3Ċ(OH)2 radical. The pK of its electrolytic dissociation was found to be 6.9 ± 0.2. In the absence of O2, it disappears by disproportionation to yield trichloroacetic acid. The rate constant 2k is equal to (7.0 ± 1)× 108 M–1 s–1 at pH = 5.5 and (4.4 ± 0.7)× 108 M–1 s–1 at pH = 10.8. CCl3Ċ(OH)2 adds O2 with k=(1.0 ± 0.2)× 109 M–1 s–1. The resulting peroxy radical CCl3O2(OH)2 is a bivalent acid with the pK-values of 3.3 ± 0.3, and 8.7 ± 0.3, respectively. Two peroxyradicals react with 2k=(1.7 ± 0.3)× 108 M–1 s–1 to produce a product that finally disappears by first order kinetics. The product is assigned the structure of a hydrotetroxide, CCl3C(OH)2O4H, which is strongly dissociated into CCl3C(OH)2·+ HO2·. Its decay is explained by the loss of oxygen.Item Radiation Chemistry and Photochemistry of Oxychlorine Ions: Part 3.—Photodecomposition of Aqueous Solutions of Chlorite Ions(Journal of the Chemical Society : Faraday Transaction - I. The Chemical Society, London. 1972, 68 (5), 1972) Buxton, G. V.; Subhani, M. S.The steady state and flash photolysis of aqueous solutions of chlorite ion has been investigated. The primary photodecomposition reactions are ClO–2[graphic omitted]ClO–+ O (a), ClO–2[graphic omitted]ClO–+ O–(b), ClO–2[graphic omitted](ClO–2)*[graphic omitted]ClO2+ ClO–+ O–(c), with the oxygen atom being formed in the 3P state at 365 nm, and in the 1D state at 313 nm and 253.7 nm. (ClO–2)* may be a long lived triplet state of chlorite ion. The primary quantum yields obtained at pH 10 are the following: (i) at 365 nm, ϕa= 0.23 ± 0.03, ϕb=ϕc= 0.077 ± 0.003., (ii) at 313 nm, ϕa= 0.066 ± 0.002, ϕb=ϕc= 0.065 ± 0.003, (iii) at 253.7 nm, ϕa= 0.11 ± 0.005, ϕb=ϕc= 0.08 ± 0.003. A complete mechanism for the photodecomposition is proposed, and the data are consistent with the reaction of O(3P) with ClO–2 proceeding by two paths O(3P)+ ClO–2→ O2+ Cl–+ O(3P)(d), O(3P)+ ClO–2→ ClO–3(e) with kd/ke= 1.50 ± 0.27.Item Radiation Chemistry and Photochemistry of Oxychlorine Ions: Part 2.—Photodecomposition of Aqueous Solutions of Hypochlorite Ions(Journal of the Chemical Society : Faraday Transaction - I. The Chemical Society, London. 1972, 68 (5), 1972) Buxton, G. V.; Subhani, M. S.The photodecomposition of alkaline aqueous solutions of hypochlorite ion has been investigated using steady state and flash photolysis techniques. At 365 nm the primary products are O(3P), O–, Cl and Cl– formed by the following processes [graphic omitted] with ϕa= 0.28 ± 0.03 and ϕb= 0.08 ± 0.02. At 313 nm and 253.7 nm O(1D) is also produced ClO–→ Cl + O(1D)(c) and the quantum yields are ϕa= 0.075 ± 0.015, ϕb= 0.127 ± 0.014, ϕc= 0.020 ± 0.015 at 313 nm, and ϕa= 0.074 ± 0.019, ϕb= 0.278 ± 0.016, ϕc= 0.133 ± 0.017 at 253.7 nm. The relative rates of reaction of O(3P) with O2, ClO– and ClO–2 have been found to be in the ratios 1 : 2.8 : 15.9. O(3P) reacts with ClO– and ClO–2 by abstraction of O as well as by addition. A complete reaction mechanism for the photodecomposition of ClO– is proposed.Item Radiation Chemistry and Photochemistry of Oxychlorine Ions: Part 1.—Radiolysis of Aqueous Solutions of Hypochlorite and Chlorite Ions(Journal of the Chemical Society : Faraday Transaction - I. The Chemical Society, London. 1972, 68 (5), 1972) Buxton, G. V.; Subhani, M. S.The radiolysis of aqueous solutions of ClO– and ClO–2 has been investigated using pulse and steady state methods. The absorption spectrum of ClO has been identified (λmax= 280 nm) and the complete reaction mechanism has been established in the case of ClO– and proposed in the case of ClO–2. The following rate constants have been evaluated (units of M–1 s–1): e–aq+ ClO–→ Cl–+ O–(5.3 ± 1.0)× 1010, e–aq+ ClO–2→ ClO–+ O–(4.5 ± 0.5)× 1010, OH + ClO–→ ClO + OH–(9.0 ± 0.5)× 109, OH + ClO–2→ ClO2+ OH–(6.3 ± 0.5)× 109, O–+ ClO–→ ClO + O2–(2.4 ± 0.1)× 108, O–+ ClO–2→ ClO2+ O2–(1.9 ± 0.1)× 108, 2ClO → Cl2O2 1.5 × 1010(2k) Values of the radical and molecular yields obtained for dilute alkaline solution are: G(e–aq)+G(H)= 2.92 ± 0.05, G(OH)= 2.41 ± 0.12, G(H2)= 0.42 ± 0.02 and G(H2O2)= 0.70 ± 0.01.Item Photochemistry and Radiation Chemistry of Anthraquinone-2-sodium-sulphonate in Aqueous Solution: Part 1.—Photochemical Kinetics in Aerobic Solution(Journal of the Chemical Society : Faraday Transaction - I. The Chemical Society, London. 1972, 68 (4), 1972) Clark, K. P.; Stonehill, H. I.When aqueous solutions of anthraquinone-2-sodium-sulphonate (D) are photolyzed the quinone becomes hydroxylated and (in the absence of oxygen) reduced. On the basis of the kinetics of the photohydroxylation in air or oxygen saturated solutions (pH 2–14), two alternative mechanisms are proposed, the 3D*/S (S = H2O or OH–) and the 3D*/D. In the former, D attacks S to produce an adduct DOH– which is converted by ground-state D to the radical DOH·. In the latter, 3D* attacks D to form a solvent caged radical pair {D·+ D·–}, the D·+ constituent then reacting with S to give OH· radicals which with D yield DOH·. This intermediate is converted by oxygen to hydroxy product. Neither continuous irradiation kinetics nor conventional µs flash photolysis permits discrimination between these schemes. The thermodynamic feasibility of OH· production by the 3D*/D reaction is demonstrated.Item Photochemistry and Radiation Chemistry of 9,10-Anthraquinone-2-sodium Sulphonate in Aqueous Solution: Part 2.—Photochemical Products 1(Journal of the Chemical Society : Faraday Transaction - I. The Chemical Society, London. 1972, 68 (9), 1972) Clark, K. P.; Stonehill, H. I.Anthraquinone-2-sodium sulphonate in “aqueous” solutions within the range pH 14 to 100% H2SO4(and also in oleum) is both reduced and hydroxylated when irradiated with u.v. or visible light. The major hydroxy-photoproducts were isolated and identified as a 3 : 2 mixture of isomeric α-and β-hydroxy derivatives of the starting material in the range 40 % H2SO4 to pH 9; outside this region the relative amount of α isomer produced falls off rapidly and in strong acid or alkali only the β-hydroxy product is obtained. Prolonged irradiation produces also small amounts of polyhydroxy derivatives. The pH-dependence of the ratio of α- and β-hydroxy product yields is correlated with ionization of hydroxyl radical adduct intermediates.Item γ-Radiolysis of Diethyl Succinate(Journal of the Chemical Society : Faraday Transaction - I. The Chemical Society, London. 1972, 68 (9), 1972) Mills, K. J.; Nosworthy Peto, J. M.Diethyl succinate has been irradiated under vacuum with 60Co γ-radiation. An attempt was made to identify and measure the complete product spectrum. Twenty different products were found after a maximum total dose of 9 × 1023 eV l.–1. The most abundant were ethanol, ethyl propionate, ethane, hydrogen, carbon monoxide, acetaldehyde and carbon dioxide. With the possible exception of acetaldehyde, G-values for these products were independent of the dose in the range studied. Gas yields were also measured in the presence of small amounts of additives (FeCl3, H2O or CH2 : CH2). Possible mechanisms for product formation are discussed.