What Is Hydrogen Peroxide?
Hydrogen peroxide is a colorless compound with the chemical formula H2O2, known for its weak, characteristic ozone smell.
Discovered by French chemist Tenard in 1818, hydrogen peroxide is celebrated as an eco-friendly chemical. Its decomposition into water and oxygen eliminates concerns about environmental pollution.
Uses of Hydrogen Peroxide
Containing activated oxygen, hydrogen peroxide is utilized for bleaching, chemical reactions, sterilization, and deodorization.
1. Bleaching
In response to growing environmental awareness, the demand for chlorine-free bleaching methods, especially in the paper and pulp industry, is on the rise. Hydrogen peroxide offers a shorter bleaching process while maintaining quality, making it ideal for cellulose-based fibers.
2. Deodorization and Corrosion Prevention
It effectively oxidizes hydrogen sulfide produced in sewage treatment plants, facilitating deodorization and detoxification.
3. Soil Improvement
Oxidation of organic contaminants in soil can expedite soil purification.
4. Surface Treatment
Hydrogen peroxide is employed for the soft etching of printed circuit boards and similar applications.
5. Sterilization
For safety reasons, hydrogen peroxide has replaced formaldehyde in disinfection and sterilization processes. It cleans and sterilizes food production equipment and containers. Oxidol, used for skin abrasions disinfection, contains diluted hydrogen peroxide.
6. Refining
Adding hydrogen peroxide to metal salt solutions, like those of copper, zinc, and nickel containing iron impurities, enables iron recovery as a precipitate, aiding in metal refining.
7. Oxidizing Agent
Hydrogen peroxide serves as a neutral, environmentally friendly oxidant, substituting chlorine-based oxidants in the production of various chemicals, including organic peroxides and sodium chlorite.
- Oxidation of phenol to produce hydroquinone and catechol
- Oxidation of acrolein or methacrolein to produce methacrylic acid or methacrylate
- Conversion of veratraldehyde to p-cresol
- Transformation of cyclohexanone into higher dibasic acid esters
- Production of L-Tartaric Acid from Maleic Anhydride
Properties of Hydrogen Peroxide
At room temperature, hydrogen peroxide is a colorless liquid with a molecular weight of 34.02. Its aqueous solutions have specific gravities and melting and boiling points varying by concentration. It is soluble in alcohol and ether and requires careful handling due to explosiveness at concentrations above 66%. Decomposition into water and oxygen can be catalyzed by substances like manganese dioxide.
In acidic solutions, hydrogen peroxide acts as a potent oxidizing agent, while it can serve as a reducing agent in basic solutions. Its known derivatives include peracetic acid, caroic acid, and potassium persulfate.
Structure of Hydrogen Peroxide
The molecule of hydrogen peroxide features a bond between two oxygen atoms. This peroxide bond is characterized by repulsion between non-covalent electron pairs and minimal overlap of covalent pairs, resulting in low bonding energy.
Other Information on Hydrogen Peroxide
Methods of Producing Hydrogen Peroxide
1. Auto-Oxidation Method
The anthraquinone autoxidation method, developed by Kemira in Finland, is the predominant global production process.
2. Direct Synthesis Method
This method synthesizes hydrogen peroxide from hydrogen and oxygen under pressure, using a catalyst.
3. Oxygen Reduction Method
Oxygen gas is introduced at the cathode during sodium hydroxide electrolysis, yielding hydrogen peroxide.
4. Electrolysis Method
Electrolyzing ammonium hydrogen sulfate produces hydrogen peroxide from the resultant ammonium persulfate.
5. Alcohol Oxidation Method
Hydrogen peroxide is obtained through the oxidation of isopropanol.