Role of Oxygen in the Photolysis of Iodides

Abstract

THE decomposition by ultra-violet light of organic compounds containing iodine in solution has been the subject of many investigations, and references to this phenomenon are scattered throughout the photochemical literature. Summaries of the results and conclusions reached by the various investigators have been fairly well dealt with in recent books on the subject¹. In the majority of cases, the quantum yields of the photochemical process have been determined by the amount of iodine formed in relation to the light absorbed. For the alkyl iodides, at least, these yields show no intelligible variation among themselves, and often the yield for a particular iodide varies from one investigator to another. There always has been a doubt as to whether or not dissolved oxygen was involved in the photolysis², in spite of the fact that many investigators have taken the trouble to distil their materials in vacuo, or to bubble inert gases through the solution before the photolysis. More convincing work along these lines has been undertaken in recent years by Olaerts and Jungers³; but it remains to be seen if they have really succeeded in removing the last trace of oxygen from their solutions.