This review discusses different aspects of the oxidative dehydrogenation reaction of ethylbenzene to styrene over iron-based oxides, emphasizing the properties of the catalysts and the participation of active sites, as well as the deactivation and regeneration processes using soft oxidants. In addition, innovations and future trends are discussed, which can encourage the design of more resistant catalysts and sustainable processes.

Abstract

The production of styrene (ST) by the petrochemical industry has traditionally relied on the ethylbenzenedehydrogenation (EB) reaction, using iron-based catalysts. Estimates suggest that in 2025, the production of EB and ST will surpass 36 and 41 million tons, respectively. In this manner, the major aspects that led to the present stage of EB and ST production were described, discussing historical aspects, alternatives to produce these solvents, its characteristics, types of oxidants, and properties of iron-based catalysts. Noteworthy advancements in this field include the utilization of CO₂ as a soft oxidant and the employment of innovative catalysts derived from green synthesis methods. On the other hand, as an alternative to the fossil source for EB production, the utilization of lignin from biomass emerges as a promising eco-friendly approach. The potential for implementing the ODH reaction in alternative reactors gives rise to questions regarding the necessity for industry to adapt to current climate needs. Furthermore, certain aspects of the mechanism have been called into question, as some fundamental points remain to be fully consolidated. These include the extent of the participation of CO₂ in the reactivation of the active sites and the origin of the deposited coke.