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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]
Friedel–Crafts reactions have been used in the synthesis of several triarylmethane and xanthene dyes. [26] Examples are the synthesis of thymolphthalein (a pH indicator) from two equivalents of thymol and phthalic anhydride: A reaction of phthalic anhydride with resorcinol in the presence of zinc chloride gives the fluorophore fluorescein.
This is an example of the Schotten–Baumann reaction: C 6 H 5 COCl + HOC 6 H 5 → C 6 H 5 CO 2 C 6 H 5 + HCl. 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
Usually phenol ethers are synthesized through the condensation of phenol and an organic alcohol; however, other known reactions regarding the synthesis of ethers can be applied to phenol ethers as well. Anisole (C 6 H 5 OCH 3) is the simplest phenol ether, and is a versatile precursor for perfumes and pharmaceuticals. [1]
Formyl functional group is shown in blue. Formylation refers to any chemical processes in which a compound is functionalized with a formyl group (-CH=O). In organic chemistry, the term is most commonly used with regards to aromatic compounds (for example the conversion of benzene to benzaldehyde in the Gattermann–Koch reaction).
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:
[6] [7] Due to the two step nature, the Raschig–Hooker process can be used to produce either chlorobenzene or phenol. Reaction scheme of the Raschig-Hooker process. 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 ...