1) Inorganic reaction method: The inorganic method is the earliest method used to prepare hydrogen peroxide, that is, acidifying barium peroxide or other inorganic peroxides with sulfuric acid or phosphoric acid to prepare hydrogen peroxide, and at the same time forming water-insoluble barium salts or other substances. The reaction equation is as follows:
BaO2 H2SO4=BaSO4 H2O2
NaO2 H2SO4 10 H2O=Na2SO4·10H2O H2O2
Barium peroxide can pass through in an oxygen atmosphere Obtained by roasting barium oxide. Hydrogen peroxide cannot be produced on a large scale using this method, and the insoluble barium salt produced cannot be recycled and reused. Later, someone developed the use of carbonic acid formed by dissolving carbon dioxide in water to acidify barium peroxide to prepare hydrogen peroxide. The advantage of this method is that the generated barium carbonate can be decomposed into barium oxide through high-temperature roasting, thereby recycling the barium oxide. The hydrogen peroxide content produced by this method is not high, the operation is troublesome and energy-consuming, and it has been eliminated in the industrial production method of hydrogen peroxide.
2) Hydrolysis of organic peroxides: Similar to the inorganic method, hydrogen peroxide can also be produced by hydrolysis of peroxide organic matter. First, acetaldehyde is controlled to form peracetic acid through auto-oxidation, and then the generated peracetic acid is hydrolyzed to obtain a mixture of hydrogen peroxide and acetic acid. To separate the hydrogen peroxide in the mixture, distillation can be used, or calcium salt can be added to the mixture to precipitate the hydrogen peroxide into calcium peroxide, and then acidification can be used to prepare hydrogen peroxide. This method is complex to operate and has only appeared in patents and has no practical application.
3) Auto-oxidation of hydrocarbons: Hydrogen peroxide can be directly produced by partial oxidation of hydrocarbons in the gas phase. However, in this method, hydrocarbons may form many by-products, which hinders the separation, purification and concentration of hydrogen peroxide. This has caused great inconvenience. This method has only appeared in patents and has no application examples. Hydrocarbons can also be first formed through liquid-phase oxidation reactions to form corresponding hydroperoxides, and then hydrogen peroxide can be produced indirectly through hydrolysis of the peroxides generated. Only a few hydrocarbons can obtain higher yields through this method. The most widely reported one is tert-butyl hydroperoxide.
4) Isopropyl alcohol oxidation method: This method uses isopropyl alcohol as raw material, hydrogen peroxide or other peroxides as initiator, and uses air or oxygen for liquid phase oxidation to generate hydrogen peroxide and acetone. This method was successfully developed by the American Shell Company and has been industrialized in the United States, Russia, and Japan. The disadvantage of this method is that it needs to consume a large amount of isopropyl alcohol and requires a large investment. It also needs to find a consumer market to produce the same amount of acetone while obtaining hydrogen peroxide. In addition, the produced hydrogen peroxide is also difficult to separate and purify, so this method uses not much.
5) Electrolysis method: This method was first discovered by Medinger during the electrolysis of sulfuric acid in 1853. Later, after many improvements, it was gradually improved from the first persulfate method to the potassium persulfate method, and finally to the persulfate method. The ammonium sulfate method became the main production method of hydrogen peroxide in the first half of the 20th century. The ammonium persulfate method uses platinum as the anode and graphite as the cathode. The chemical reaction equation is: 2 NH4HSO4→ (NH4) 2S2O8 H2↑
(NH4) 2S2O8 2 H2O →2 NH4HSO4 H2O2
Although the hydrogen peroxide product produced by the electrolysis method is of high quality, it requires the consumption of metal platinum and a large amount of electricity. The cost is high, and the equipment production capacity is low, which is not conducive to large-scale production. It has now been basically replaced by the anthraquinone method.