In 1855, the Frenchman M. Batelo first reported the production of isopropanol by hydration of propylene and sulfuric acid, which is called indirect hydration. In 1919, American C. Ellis conducted industrial development. At the end of 1920, the New Jersey Standard Oil Company of the United States established the production device using the Ellis method, and was formally put into production. In 1951, the British company Bu Nei Men Chemical Industry Co., Ltd. began to use isopropyl alcohol to produce isopropanol. Since then, countries have adopted this method and made improvements.
Indirect hydration: Propylene reacts with sulfuric acid to produce isopropyl hydrogen sulfate, which is hydrolyzed to form isopropanol. The reaction formula is: CH3CH=CH2+H2SO4→(CH3)2CHOSO3H; (CH3)2CHOSO3H+H2O→ (CH3)2CHOH + H2SO4, the concentration of sulfuric acid used is generally greater than 60% by mass, the reaction is carried out at 2 to 2.8 MPa and 60 to 65°C; the hydrolysis is carried out under slight pressure and below 30°C.
Direct hydration: Propylene and water are heated and pressurized in the presence of a catalyst for hydration reactions to produce isopropanol with a selectivity of 96%. The reaction formula is: CH3CH=CH2+H2O─→(CH3)2CHOH The catalysts used are tungsten compounds, phosphoric acid and ion exchange resins, and more used are supported phosphoric acid catalysts (see solid acid catalyst). The process conditions are 2 ~6MPa, 240 to 260°C. Compared with the indirect method, this method does not have problems such as sulfuric acid corrosion and dilute acid concentration, and thus it occupies a major position in industrial production.