Catalysis in the system 1,2-dichloroethane iron(III) chloride

• Main Author: Taylor, Douglas S. C
• Format: Dissertation
• Language: English
• Published: University of Glasgow 2002
• Subjects: QD Chemistry

1,2-Dichloroethane (EDC) plays a major role as an intermediate in the PVC chain and as a feed material for C2 solvent manufacture. Knowledge and understanding at the fundamental level of the role of trace inorganic species present during EDC manufacturing are very limited. The primary aim of this work was therefore to determine the roles of these species. Due to the lack of, and in certain cases contradictory, literature it was important to re-examine the system at its most fundamental levels. The reaction medium in which EDC is produced contains several different organic and inorganic constituents. The most important are 1,2-dichloroethane (present not only as the reaction product but also the solvent), ethane, dichlorine, hydrogen chloride, ethyl chloride, water and iron amongst others (a full description of reaction constituents is provided in chapter 1). The current work has established the presence of [FeCl4]- as the dominant species in solution. Importantly, a precursor to this species has also been identified in dilute and purer/dryer EDC/FeCl3 solutions. This precursor is believed to take the form of a molecular species such as FeCl3.χH2O (χ = 1,2 etc.). The work has also established that the EDC/FeCl3 solution system is inevitably complicated by the presence of FeCl3. This is particularly important when the behaviour of "free" water within the system is examined. The work has established that addition of H2O and/or HCl leads, with time, to the formation of a significant, probably water-related, species in the observed in the infra-red spectrum. A simple model is proposed to account for events occurring at the solid/solution interface.