Technology Type

Around 80% of styrene is produced by the dehydrogenation of ethylbenzene. This is achieved using superheated steam (up to 600 °C) over an Iron(III) Oxide Catalyst. The reaction is highly endothermic and reversible, with a typical yield of 88–94%^[1]:

The following competitive reactions also take place^[2]: 

The crude ethylbenzene/styrene product is then purified by distillation. As the difference in boiling points between the two compounds is only 9 °C at ambient pressure this necessitates the use of a series of distillation columns. This is energy intensive and is further complicated by the tendency of styrene to undergo thermally induced polymerisation into polystyrene, requiring the continuous addition of polymerization inhibitor to the system^[1].

References

1. Wikipedia, Styrene.
2. Amaury Pérez-Sánchez et al., 28^th Apr 2017, Simulation of the styrene production process via catalytic dehydrogenation of ethylbenzene using CHEMCAD® process simulator, Tecnura, vol. 21, no. 53, pp. 15-31, 2017.