The chemical effects of storing hydrazine containing carbon dioxide impurity in stainless steel systems

Abstract

The effect of low concentrations (<250 ppm) of dissolved carbon dioxide (carbazic acid) on the rate of decomposition of hydrazine, in both stainless steel and glass vessels, has been investigated. In a stainless steel vessel at 60°C the rate of hydrazine decomposition was found to be directly proportional to the total concentration of added carbon dioxide (above about 20 ppm) while for a glass vessel at 51°C the relationship between concentration of added carbazic acid and hydrazine decomposition rate is best interpreted in terms of a Langmuir isotherm equation. The preparation of some carbazato-complexes of iron, chromium and nickel, such as may be formed during the hydrazine/carbon dioxide corrosion of stainless steel, is also reported. Additions of small amounts of dicarbazatodihydrazineiron (II) to hydrazine in a glass vessel had no measurable effect on the decomposition rate at 43°C. Tricarbazatochromium (III) dihydrate was found to be similarly inactive while the principal nickel carbazato- complex is completely insoluble in hydrazine.