Preparation
Potassium peroxides have been prepared by carefully controlled oxidation of the metals with the exact amount of air or nitric oxide, but it is difficult to prepare the pure peroxides in this manner because of the ease with which the peroxides are oxidized to the superoxide. They can also be prepared by careful oxidation of liquid ammonia solutions of the metals, using the stoichiometric quantity of oxygen for peroxide formation. They can also be prepared by the thermal decomposition of the superoxides in vacuum; for example, potassium superoxide decomposes at about 400°C.
Chemical Properties
yellow amorphous mass; decomposes in water, evolving oxygen; oxidizing agent; used for bleaching, in oxygen generating gas masks [HAW93]
Uses
Oxidizing agent, bleaching agent, oxygen-
generating gas masks.
General Description
A yellow granular solid. Mixtures of potassium peroxide and combustible material readily ignited by friction, heat or contact with moisture. Prolonged exposure to fire or heat may cause vigorous decomposition of the material and rupture of the container. Used as a bleach.
Air & Water Reactions
Reacts exothermically with water (or moisture in the air) to give oxygen and a caustic solution, potassium hydroxide [NFPA 491M] .
Reactivity Profile
potassium peroxide is a strong oxidizing agent. Reacts readily with reducing agents, including most organic compounds, to generate heat and products that may be gaseous (causing pressurization of closed containers). The products may themselves be capable of further reactions (such as combustion in the air). A quantity left on a piece of paper in the open air usually starts a fire in the paper spontaneously in a few minutes [Freeman].
Hazard
Dangerous fire and explosion risk in con-
tact with organic materials, strong oxidizing agent.
Irritant to skin and tissue.
Health Hazard
Inhalation causes respiratory irritation. Ingestion causes severe burns of mouth and stomach. Contact with eyes or skin causes irritation and caustic burns.
Fire Hazard
Behavior in Fire: Increases intensity of fire and can start fires when in contact with organic combustibles
Safety Profile
Dangerous fire hazard
by spontaneous chemical reaction. It is a
very powerful oxidzer. Fires of this material
should be handled like sodurn peroxide
fires. Moderate explosion hazard by
spontaneous chemical reaction. Explodes on
contact with water, forming H2O2 and
KOH. Violent reactions with air, Sb, As, O2 ,
K. Vigorous reaction on contact with
reducing materials. On contact with acid or
acid fumes, it can emit toxic fumes.
Incompatible with carbon, diselenium
dichloride, ethanol, hydrocarbons, metals.
When heated to decomposition it emits
toxic fumes of K2O . See also PEROXIDES,
E
INORGANIC.
