The Dow process process is a method of

phenol Phenol (also known as carbolic acid, phenolic acid, or benzenol) is an aromatic organic compound with the molecular formula . It is a white crystalline solid that is volatile and can catch fire. The molecule consists of a phenyl group () ...

production through the

hydrolysis Hydrolysis (; ) is any chemical reaction in which a molecule of water breaks one or more chemical bonds. The term is used broadly for substitution reaction, substitution, elimination reaction, elimination, and solvation reactions in which water ...

chlorobenzene Chlorobenzene (abbreviated PhCl) is an aryl chloride and the simplest of the chlorobenzenes, consisting of a benzene ring substituted with one chlorine atom. Its chemical formula is C6H5Cl. This colorless, flammable liquid is a common solvent a ...

Details

Benzene Benzene is an Organic compound, organic chemical compound with the Chemical formula#Molecular formula, molecular formula C6H6. The benzene molecule is composed of six carbon atoms joined in a planar hexagonal Ring (chemistry), ring with one hyd ...

can be readily converted to chlorobenzene by

nucleophilic aromatic substitution A nucleophilic aromatic substitution (SNAr) is a substitution reaction in organic chemistry in which the nucleophile displaces a good leaving group, such as a halide, on an aromatic ring. Aromatic rings are usually nucleophilic, but some aromatic c ...

via a benzyne intermediate. Chlorobenzene is treated with aqueous

sodium hydroxide Sodium hydroxide, also known as lye and caustic soda, is an inorganic compound with the formula . It is a white solid ionic compound consisting of sodium cations and hydroxide anions . Sodium hydroxide is a highly corrosive base (chemistry), ...

at 350 °C and 300 bar or molten sodium hydroxide at 350 °C to convert it to

sodium phenoxide Sodium phenoxide (sodium phenolate) is an organic compound with the formula NaOC6H5. It is a white crystalline solid. Its anion, phenoxide, also known as phenolate, is the conjugate base of phenol. It is used as a precursor to many other organic ...

, which yields phenol upon acidification. When 1- sup>14C1-chlorobenzene was subjected to aqueous NaOH at 395 °C, ''ipso'' the substitution product 1- sup>14Cphenol was formed in 54% yield, while the ''cine'' substitution product 2- sup>14Cphenol was formed in 43% yield. This indicates that an elimination-addition (benzyne) mechanism is predominant, with perhaps a small amount of product from addition-elimination (S_NAr).

References

Chemical processes Dow Chemical Company {{chem-process-stub