Catalytic Activity of Pigments (III)

Catalytic Activity of Pigments for Castor Oil Oxidation by Differential Thermal Analysis

Abstract

Oxidation of castor oil by the pigments was discussed with oxygen gas flow-DTA. The pigments were classified into three groups by the oxidation behavior of castor oil.
Group 1. The type of pigments which promotes the oxidation of castor oil ; Hydrated Chromium Oxide, Red Iron Oxide, Yellow Iron Oxide, Black Iron Oxide, Prussian Blue
Group 2. What has no influence for the oxidation of castor oil ; Zinc Oxide, Kaolinite, Mica, Ultramarine Blue, Silica
Group 3. What inhibits the oxidation of castor oil ; Talc, Titanium Dioxide
The pigments promoting the oxidation of castor oil were the color pigments with the transition elements such as chromium, iron, manganese. The oxidation activity is considered to have no relation to acid-base sites of pigments surface. Moreover, this oxygen gas flow-DTA method was in good agreement with the active oxygen method (AOM).