24.1 Introduction

•  In this lecture we present the process technology for the production of styrene and pthalic anhydride.

•  Styrene is produced from benzene via the ethylbenzene route followed by dehydrogenation.

•  Pthalic anhydride is produced from Napthalene and o-Xylene.

•  We first present the process technology associated to styrene production.

24.2 Styrene

24.2.1 Reactions

Alkylation of Benzene

•  Benzene + ethylene → Ethyl benzene.

•  Catalyst: AlCl₃ granules.

•  C₂ H₅Cl provides hydrogen and chlorine free radicals.

•  Operating conditions: 95°C and 1 atm pressure.

•  Reaction is exothermic.

Dehydrogenation of ethylbenzene

•  Ethylbenzene à Styrene + Hydrogen.

•  Reaction is endothermic.

•  Catalyst: SnO or FeO.

•  Operating conditions: 800°C.

24.2.2 Process technology (Figure 24.1)

Figure 24.1 Flow sheet of manufacture of styrene