Hydrogen peroxide was prepared first by Thenard in 1818. It is a colorless liquid at room temperature with a bitter taste. Small amounts of gaseous hydrogen peroxide occur naturally in the air. Hydrogen peroxide is unstable, decomposing readily to oxygen and water with the release of heat. Although non-flammable, it is a powerful oxidizing agent that can cause spontaneous combustion when it comes in contact with organic material.
There are two main methods to produce H2O2 as described below:
Method 1: Auto-oxidation of ethyl anthraquinones in a solvent such as toluene or ethylbenzene. The product ethyl anthraquinone is reduced by hydrogen over supported nickel or platinum catalyst to regenerate back the starting material, ethyl anthraquinone for continuous production of H2O2.
Method 2: Electrolytic conversion of aqueous sulfuric acid to peroxydisulfate followed by hydrolysis to H2O2. This is also known as the Weissenstein process.
Hydrogen peroxide is mainly used as a bleaching agent in the pulp and paper industry during the chemical and mechanical pulping processes.
Hydrogen peroxide is used as a bleaching agent in the textile industry and they are more environmentally friendly than chlorine-based bleaches. Hydrogen peroxide is also used in dyes. Sulfur dyes work with an oxidation-reduction dyeing method and hydrogen peroxide is used as an oxidizing agent. Once the dyes are adsorbed onto the cellulosic, oxidation will settle the dyes permanently and changing it into a water-insoluble form.
Hydrogen peroxide is a cleaner oxidizing agent that is used to treat wastewater, contaminated soil, and toxic air emissions.
Hydrogen peroxide is also used to manufacture a wide range of organic and inorganic compounds such as hydroquinone, ketones, aldehydes, alcohols, hydro-oxyl amines, epoxy derivatives, etc.
Hydrogen peroxide is used in pharmaceuticals for preparing disinfectants, food processing for sanitizing of packages, etc. They are even used as propellants and in explosives. In addition, Hydrogen peroxide is mainly used in the manufacturing of sodium percarbonate and other chemicals which are generally used as mild bleaches for the laundry.