On the Existence of Active Oxygen / Thesis Presented for the Attainment of the Degree of Doctor of Philosophy at the Johns Hopkins University

Thesis presented for the attainment of the degree of Doctor of Philosophy at the Johns Hopkins University.
by Edward H. Keiser.
Baltimore, 1884


To test this hypothesis he made experiments with palladium hydrogen. Graham has described the energetic reducing power of this compound but that it can also cause oxidations Hoppe-Seyler showed by bringing some strips of palladium charged with hydrogen into a solution of indigo in the presence of air. The solution soon became yellow and after a time the indigo was completely destroyed. If palladium hydrogen be brought into a neutral solution of potassium iodide and starch, the liquid becomes blue in a few minutes, after which the starch is slowly destroyed. In a similar way benzene was oxidized to phenol. “These experiments and others of a similar nature,” he asserts, “admit of no explanation other than that the active hydrogen renders the oxygen active, and since the former unites with oxygen we cannot well conceive of the process without supposing that the hydrogen in uniting with one atom of the molecule O 2 sets the remaining atom free, thus making it active.” “Just as the hydrogen atom cannot exist in a free state so the active oxygen, if no oxidizable material is present, unites with water to form hydrogen dioxide, or with inactive oxygen to form ozone.”
He then compares active oxygen with the antozone of Schönbein and says that several of the properties of antozone can be ascribed to active oxygen above all that property of antozone of oxidizing water to hydrogen dioxide. The only difference between the two being that active oxygen has but a momentary existence while antozone was supposed to be capable of isolation.
The different behavior of ozone and active oxygen was then shown by the following experiment:—“A slow current of air free from carbon dioxide was passed into a flask containing moist phosphorus, from there into a second flask where the ozonized air came in contact with a somewhat slower current, consisting of a mixture of three volumes of oxygen to one of carbon monoxide, carefully purified from carbon dioxide. From the second flask the gases were passed through a clear solution of baryta water.” “After all carbon dioxide had been removed from the apparatus the baryta water remained perfectly clear (völlig klar) after the gases had passed through for six hours.” “But, on the other hand, if the mixture of carbon monoxide and oxygen was passed into the first flask, containing the moist phosphorus and in which according to our theory active oxygen must occur, then the result is quite different, the baryta water becomes cloudy in a short time and in the course of an hour there is formed an abundant precipitate (‘reichlicher Niederschlag’) of barium carbonate.”