Raschig Hooker Trial

The Raschig-Hooker process is a large-scale process for the production of phenol . It was first published by Fritz Raschig in 1939 and represented an alternative to the sulfonic acid process and chlorobenzene pressure saponification .

The process

In the first step, benzene is chlorinated to chlorobenzene . This happens at temperatures around 250 ° C in a hydrochloric acid environment in the presence of oxygen . Copper (II) chloride is used as a catalyst together with aluminum hydroxide . The chlorobenzene produced in this step is converted into phenol in the second step by acid hydrolysis , which leads to the formation of hydrogen chloride .

${\displaystyle \mathrm {(1)\ \ C_{6}H_{6}\ +\ HCl\ +\ 1/2\ O_{2}\longrightarrow \ C_{6}H_{5}Cl\ +\ H_{2}O} }$

${\displaystyle \mathrm {(2)\ \ C_{6}H_{5}Cl\ +\ H_{2}O\longrightarrow \ C_{6}H_{5}OH\ +\ HCl} }$

Only benzene and oxygen are included in the net reaction .

${\displaystyle \mathrm {C_{6}H_{6}\ +\ 1/2\ O_{2}\longrightarrow \ C_{6}H_{5}OH} }$

The copper (II) chloride catalyst is reduced to copper (I) chloride in the course of the reaction and is later oxidized again.

The utilization of the hydrochloric acid used for chlorination depends on the temperature and has a maximum of around 250 ° C. In this way, sales of 99.5% can be achieved. Higher chlorinated benzene derivatives are produced as by-products . The isomers of dichlorobenzene have the main part . Tri-, tetra-, penta- and hexachlorobenzene are also produced in small amounts in decreasing amounts.

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1. ↑ ^{a b c d} W. Mathes, F. Raschig: The Raschig process for the production of phenol , in: Angew. Chem. 1939 , 52 , 591-598.