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The main steps in this process are the production of chlorobenzene from benzene, hydrochloric acid and oxygen, and the subsequent hydrolysis of chlorobenzene to phenol. [4] The first step uses either a copper or iron chloride catalyst and exposes the materials to air at 200–250 °C.
The term stems from cumene (isopropyl benzene), the intermediate material during the process. It was invented by R. Ūdris and P. Sergeyev in 1942 (USSR), [1] and independently by Heinrich Hock in 1944. [2] [3] This process converts two relatively cheap starting materials, benzene and propylene, into two more valuable ones, phenol and acetone.
Benzene can be easily converted to chlorobenzene by nucleophilic aromatic substitution via a benzyne intermediate. [1] It is treated with aqueous sodium hydroxide at 350 °C and 300 bar or molten sodium hydroxide at 350 °C to convert it to sodium phenoxide , which yields phenol upon acidification. [ 2 ]
More so than thiophenol, benzeneselenol is easily oxidized by air. The facility of this reaction reflects the weakness of the Se-H bond, bond dissociation energy of which is estimated to be between 67 and 74 kcal/mol. [1] In contrast, the S-H BDE for thiophenol is near 80 kcal/mol. [3] The product is diphenyl diselenide as shown in this idealized equation:
Phenol is reduced to benzene when it is distilled with zinc dust or when its vapour is passed over granules of zinc at 400 °C: [22] C 6 H 5 OH + Zn → C 6 H 6 + ZnO. When phenol is treated with diazomethane in the presence of boron trifluoride (BF 3), anisole is obtained as the main product and nitrogen gas as a byproduct. C 6 H 5 OH + CH 2 N ...
A few types of aromatic compounds, such as phenol, will react without a catalyst, but for typical benzene derivatives with less reactive substrates, a Lewis acid is required as a catalyst. Typical Lewis acid catalysts include AlCl 3, FeCl 3, FeBr 3 and ZnCl 2. These work by forming a highly electrophilic complex which is attacked by the benzene ...
Dow process (phenol), a method of phenol production through the hydrolysis of chlorobenzene Topics referred to by the same term This disambiguation page lists articles associated with the title Dow process .
In organic chemistry, dihydroxybenzenes (benzenediols) are organic compounds in which two hydroxyl groups (−OH) are substituted onto a benzene ring (C 6 H 6). These aromatic compounds are classed as phenols .