Phenol. Acetone. alpha-Methylstyrene

Phenol is a colorless liquid used in the manufacture of numerous reagents in the chemical industry (pharmaceuticals, agrochemicals, resins, nylon, explosives, etc.). It was isolated in 1834 from coal residues.

Subsequently, phenol production expanded, initially mainly for military applications (picric acid), then as a synthesis intermediate for the manufacture of resins (formophenolics, bisphenol) and nylon.

During the First World War, phenol was synthetically produced by sulfonating benzene.

Various routes were then explored: catalytic oxidation of toluene (Dow process), hydrolysis of chlorobenzene (Dow, Bayer, Raschig...). But the predominant route that soon emerged was the "cumene" process, in the 1950s (BP Chemicals, Hercules).

This synthesis route, widely used by all phenol producers, enables the co-production of acetone (in a ratio of around 0.6 t/t phenol) and a small portion of α-methylstyrene (figure 1 ).

Phenol is one of these so-called "cyclical" chemicals, where volumes and prices are conditioned by sharp fluctuations in the price of petroleum raw materials and the commissioning of new, very high-capacity production units.

The acetone fatally coproduced can also be a handicap at certain times. It's worth noting that, with this in mind, a plant based on a new process (Solutia Inc.) is due to come on stream in the near future, enabling phenol to be produced exclusively by oxidation of benzene with nitrous oxide, in a single stage.