STUDY OF THE RADIOLYSIS OF BROMAL HYDRATE SOLUTIONS USING C<sup>14</sup>-LABELLED BROMAL

Heusinger, H.; Woods, Robert J.; Spinks, J. W. T.

doi:10.1139/v59-167

Cited by 5 publications

(6 citation statements)

References 4 publications

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“…The dependence of the rate of production of acid upon the oxygen and chloral hydrate or bro~nal hydrate concentrations and upon the dose rate as predicted by equation [8] is in good agreement with the experimental results. The primary interaction of the radiation with water in dilute aqueous solutions as postulated in (a) is generally accepted.…”

Section: Rsupporting

confidence: 79%

“…Andrews and Shore (1) found a value of 1.29:l and Platford (15) found a value of 1.30:l for this ratio. For bromal hydrate solutions, the 1 : l value found for the ratio of total acid to hydrobromic acid is not in co~nplete agreement with the value of 1.20: 1 found by Woods and Spinlis (6) or of 1.16:l found by Heusinger et al (8). Regardless of the exact value of this ratio for bromal hydrate solutions, it appears that the ratio of the yield of total acid per mole of hydrohalic acid is significantly greater for chloral hydrate solutions than for bro~llal hydrate solutions.…”

Section: Rcontrasting

confidence: 58%

“…For both coinpounds the presence of oxygen causes an increased rate of production of acid (2,7,8), the increase being about the same for both. The ratio of moles of hydrol~alic acid produced per Inole of oxygen originally present is essentially the same for both cllloral hydrate and bromal hydrate solutions, the value being between 3 and 4 illoles of hydrol~alic acid per mole of oxygen (2,6,7,8). I t should be noted that the rate of production of acid remains constant a t the higher rate while any oxygen is present in the solution and then falls abruptly with the exhaustion of the oxygen, i.e.…”

Section: Rmentioning

confidence: 84%

“…( 8 ) found for oxygen depleted solutions that the ratio of the amount of total acid formed to the amount of l~ydrobron~ic acid formed was the same as when oxygen mas present in the solution. This would suggest that in the absence of oxygen the nlechanism is still much the same as in the presence of oxygen, except that reaction (c) for the rate of production of acid.…”

Section: Rmentioning

confidence: 90%

“…Some deductions about the radical S may be made from a consideration of the overall activatioil energy for the production of acid. According to equation [8], the overall activation energy will be a composite one, and hence, any discussion involving it should include a consideration of the three reactions (b), (c), and (c). I t may be speculated, however, since the overall activation energy for the chloral hydrate radiolysis is less than, or a t the most, equal to that for bronzal hydrate (2, 5 , 7 ) , that the free radical 5 has resulted from an attack on the aldehyde end of the chloral hydrate or bromal hydrate nlolecule by R. If the attack was on the halogen end of the molecule, it would be expected that the activation energy for the production of acid would be higher for chloral hydrate solutions because the bond strength of the C-Cl bond is greater than that for the C--Br bond.…”

Section: Rmentioning

confidence: 99%

See 4 more Smart Citations

The Radiation Chemistry of Aqueous Solutions of Chloral Hydrate and of Bromal Hydrate

McIntosh¹,

Eager²,

Spinks³

1964

Can. J. Chem.

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The radiation chenlistry of aqueous solutions of chloral hydrate and of bronlal hydrate has been further investigated. T h e electrical conductivity method of Andrews and Shore (1) was used to follow the appearance of acid. T h e yield of acid was found to be dependent on the dose rate, contrary t o the conclusion reached by Andrews and Shore but in agreement with the results of other workers. A reexamination of Andrews and Shore's paper indicates that a n incorrect interpretation was made of their data and reveals that, in fact, their data also indicate a dose rate dependence for the yield of acid. A free radical mechanism is proposed which is in good agreement with the obscrved dependence of the rate of formation of acid upon the dose rate and upon the solute concentration in both the presence and in the absence of oxygen.Several reports have been published on the radiation chemistry of aqueous solutions of chloral hydrate (1-6) and of bron~al hydrate (6-11). There is general agreenlent that one of the main products is the corresponding hydrohalic acid. In the earliest reported work, that of Andrews and Shore (1) on aqueous chloral hydrate solutions, the appearance of hydrochloric acid was followed by ineasureinent of the electrical conductivity of the solution. A siinilar method was used by I-Iilsenrod (4). In the other worlr referred to, the production of acid was followed by titration with standard base. Andrews and Shore (1) interpreted their results in a manner which indicated that theG value (number of illolecules of product per 100 eV of energy absorbed) of I-IC1 was independent of dose rate. I-Iilsenrod (4) did not investigate the dose rate dependence. In contrast, all of the other worlters (2, 3, 5 , 6) reported a dose rate dependence, the G value being approxiinately inversely proportional to the square root of the dose rate. A siinilar dose rate dependence was found for aqueous solutions of broinal (6-9).No satisfactory explanation for this large discrepancy in the dose rate dependence has been offered. While.it seeins unliltely, a possible explanation is that the different behavior reported arises because of the methods used to follow the appearance of the hydrohalic acid. The electrical conductivity method is not very specific, since the appearance of any electrolyte will result in an increase in electrical conductivity. The titration nlethod is more specific, since it will respond only to acidic products. I t should be noted that Andrews and Shore (1) did do sonle chloride analysis and PI-I measurements which indicated that the electrical conductivity measured by t h a n was due mainly to hydrochloric acid. By titration with a base, they found that the anlount of total acid present was solnewhat larger than that which would be expected if only hydrochloric acid was responsible for the electrical conductivity. Similarly, Woods and Spinks (7), and I-Ieusinger et al. (8)

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Section: Rsupporting

confidence: 79%

Section: Rcontrasting

confidence: 58%