Raschig process: It is one of the industrial method of prep of phenol. First chlorobenzene is prepared by treatement of benzene with HCl in the presence of heated copper catalyst at 250oC. The resulting chlorobenzene is hydrolysed by steam over silica at 500oC
Benzene + 2HCl + O2 (over Cu at 250oC) = Chloronbenzene + 2H2O
Chlorobenzene + Steam (over silica at 500oC) = Phenol + HCl
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Dow's process: It is also commercial method of preparation of phenol. Here chlorobenzene is directly prepared by chlorination of benzene in the presence of FeCl3, then chlorobenzene is treated with NaOH at high temperature and pressure to get phenol.
Benzene + Cl2 (FeCl3 catalyst) = chlorobenzene + HCl
Chlorobenzene + 2NaOH (at 360oC and high pressure) = Ar-ONa + NaCl + H2O
Ar-ONa + HCl = ArOH + NaCl