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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 readily converted to chlorobenzene by nucleophilic aromatic substitution via a benzyne intermediate. [1] Chlorobenzene 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]
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 ...
The Raschig–Hooker process's ability to make phenol makes it comparable to other methods, such as the Dow and Bayer process, which also converts benzene into phenol. In fact, the ability to recycle the hydrogen chloride made the Raschig–Hooker process preferable to the Dow and Bayer process, which requires its sodium chloride product to be ...
After exposure to 63 to 405 mg/m 3 of benzene for 1 to 5 hours, 51 to 87% was excreted in the urine as phenol over a period of 23 to 50 hours. In another human study, 30% of absorbed dermally applied benzene, which is primarily metabolized in the liver, was excreted as phenol in the urine.
Many phenols of commercial interest are prepared by elaboration of phenol or cresols. They are typically produced by the alkylation of benzene/toluene with propylene to form cumene then O 2 is added with H 2 SO 4 to form phenol (Hock process). In addition to the reactions above, many other more specialized reactions produce phenols:
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 .
Involving similar reactions, diphenyl ether is a significant side product in the high-pressure hydrolysis of chlorobenzene in the production of phenol. [ 7 ] Related compounds are prepared by Ullmann reactions .