Photolysis of acetone

The validity of above expression has been proved in this study by the example of chemisorbtion of methyl radicals. They have been produced by means of photolysis of acetone vapour. It should be noted that the deduced expression is identical to that describing adsorption of molecular oxygen on semiconductor, i. e. cr = const / [19]. For ex-... 

Note that the same sensor technique was used in rather intriguing experiments on photolysis of acetone [12], ammonia [13], nitrogen [14], oxygen [15], and carbon dioxide [16]. 

In order to verify the properties of alkyl radicals adsorbed on semiconductor ZnO film, we conducted experiments, in which methyl radicals were adsorbed from the vapour phase of acetone at room temperature. Under these conditions, the radicals were formed via photolysis of acetone vapours (for details, see Chapter 3) at small pressure of acetone (of about 0.5 Torr). 

Photolysis of acetone forms methyl radicals, isolated as dimethyl-mercury, and acetyl radicals isolated as diacetyl. Photolysis of benzo-phenone forms phenyl radicals which remove a tellurium mirror to give diphenyltellurium. 

Photolytic. Photolysis of acetone in air yields carbon monoxide and free radicals, but in isopropanol, pinacol is formed (Calvert and Pitts, 1966). Photolysis of acetone vapor with nitrogen dioxide via a mercury lamp gave peroxyacetyl nitrate as the major product with smaller quantities of methyl nitrate (Warneck and Zerbach, 1992). 

Photolysis of acetone also contributes significantly to its loss and is the dominant loss process in the upper troposphere (Gierczak et al., 1998 see Section J.3). 

Despite this fact and the low (CH3-CO) bond dissociation energy in the acetyl radical, the products of photolysis of acetone with light of wavelength 3130 A. have been shown to contain substantial amounts of diacetyl, which could only arise from the combination of acetyl radicals. 

Although a very great deal of work has been carried out on the photolysis of acetone, it is not possible to decide unequivocally whether both processes occur simultaneously or whether a primary step of type A is succeeded by a further partial breakdown of the acetyl radical. 

In fact, no appreciable quantities of hydrogen have been detected in the photolysis of acetone under these conditions. 

With the exception of the photolysis of acetone itself, no other photodecomposition of a ketone has been studied so extensively as that of hexafiuoroacetone. 

However, if the photochemical reaction is run in the presence of oxygen, then of course, the methyl radicals are oxidized, and one obtains instead methanol, formaldehyde, and their decomposition products. Now, if the vessel is pumped out after a photo-oxidation and once again a normal photolysis of acetone is run, the products in the first 10 or 15 minutes are still oxidation products rather than hydrocarbon products. It takes from 15 to 30 minutes to remove whatever it is that is attached to the wall before the normal photochemical decomposition of pure acetone products are produced. These results should remind us that oxidation system do produce species, some of which are not known or understood. 

Actually, type I cleavage occurs from both singlet and triplet excited states, as evidenced by the incomplete quenching of the photolysis of acetone by high pressures of biacetyl308 or 2-butene.243 The extent to which dissociation can be quenched is subject to large temperature and wavelength effects and depends markedly on the stability... 

Hoare203 examined the photolysis of acetone at 200°C in the presence of NO. He monitored both CH4 production and NO consumption and computed k7/k15 from the competition between reaction (7) and... 

There are isolated reports of Sh2 reactions involving attack by C-centered radicals. These are typically gas-phase reactions using the photolysis of acetone (sometimes the per-deutero or per-fluoro analog) as a source of Me, which gives CD3 with Hg(CD3)2 examples involving B and Sn have also been reported. 

The theory of the photolysis of acetone has been discussed in a comprehensive manner by Howe and Noyes.38 They have obtained new, exact experimental data in the short ultraviolet near 1,900 A which they have correlated with the earlier work in the longer ultraviolet. 

In the photolysis of acetone it is accepted96 that the primary process is the formation of a methyl and an acetyl radical ... 

This finding has been confirmed18 by photolysis of acetone-18 in light oxygen, which yielded about 10% of the carbon dioxide in the form of C018018. 

Similar methods have been employed in the photolysis of acetone in the presence of H2/ the photolysis of light and heavy acetone mixtures, the pyrolysis of ethane,- and the decomposition of C2H6Br in the presence of radioactive BrS, HBr, and DBr. ... 

F. B. Marcotte and W. A. Noyes, Jr., Discussions Faraday Soc., 10,236 (1951). Values from photolysis of acetone + O2 mixtures are tentative pending further study of the oxidative mechanism. 

L. Mandelcorn and E. W. R. Stoacie, Can. J. Chevi., 32, 79 (1954), have shown from material balances and direct observation of the formation of CH3( H2G()CH8 in the vapor-phase photolysis of acetone that this is in reasonable accord with the data. 

Photolysis of Acetone A Photochemical Source of Methyl Radicals... 

Table XIII.13. Thermodynamic Data for Some Reactions of Interest in the Photolysis of Acetone (All Gas Phase)...

In the photolysis of acetone-l2 mixtures, reported by Benson and Forbes, the ratio (CIl4)/(CO)(X = 2537 A) was always about 0.15 to 0.20, indicating either a very low efficiency for reaction 3 relative to CHs + acetone or a hot radical effect in this photolysis as well. 

Buckley and Mclauchlan measured CIDEP spectrum upon photolysis of acetone in diethyl phosphite as shown in fig. 5-9(a) [18]. The reaction occurs as follows ... 

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