Showing papers in "The Journal of Physical Chemistry in 1920"

The Catalytic Decomposition of Hydrogen Peroxide by Ferric Salts

Abstract: The decomposition of hydrogen peroxide, according to Thenard,’ is either accelerated or retarded by nearly all substances. It is, therefore, an extremely useful reaction for studying the phenomena of catalysis in homogeneous systems, and is convenient for this purpose because of the readiness with which its progress may be quantitatively followed, and also because there are no disturbing substances formed, oxygen and water being the only products of the reaction. The action of var:ous positive and negative catalysts on the decomposition of hydrogen peroxide has been exhaustively studied by various investigators, among them Bredig and his student^,^ who directed their attention to the accelerating effect of colloidal platinum and gold with various “poisoning” substances. Various enzymes, such as haemasej and catalaseJ6 have been shown to accelerate the decomposition; the action of a large variety of substances such as finely divided metals and metallic oxides, has been studied by Kastle and others.‘ There has, however, been little work done on the catalytic decomposition of hydrogen peroxide by salts of heavy metals. Schonbein studied the catalytic

On the Preparation of Colloidal Manganese Dioxide

Abstract: Three methods have this far been employed for the preparation of colloidal manganese dioxide. I. The reduction of potassium permanganate. Marck’ used hydrogen peroxide as the reducing agent; Spring and de Boeck2 sodium thiosulphate ; and Deisz3 arsenious acid. Fr6my4 obtained a red solution of manganese dioxide, by treating potassium permanganate with concentrated sulphuric acid. He could not determine, however, whether he was dealing with a true or a colloidal solution. Van Bemmelen5 used chlorine as the oxidizing agent. Trillat,6 using protective colloids such as albumin, gelatine, gum arabic, dexterine, etc., claims to have prepared colloidal manganese dioxide merely by exposing to the air alkaline solutions of manganous salts. He adduces, however, no conclusive evidence to prove that he was not dealing with complex organic salts such as complex copper glycerate GHL(OH)~.O Cu.O. C~H,,(OH)P, complex copper tartrate Na COO.CH CH COO.Na. 11. The oxidation of manganous salts.