Engineering Analysis of Laboratory Data in Electro-Organic Synthesis

301 p.Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1985.An important phase in the early evaluation of candidate processes is the incorporation of laboratory data into engineering models to design, scale-up, optimize, and identify sensitive operating parameters. The purpose of this study was to incorporate engineering models in the bench-scale data. The study focused on development of methodology rather than evaluation of a particular process candidate.The production of 1,2-dichloroethane by electrolysis of ethylene-containing hydrochloric acid solutions was studied. Ethylene chlorohydrin was the only by-product. The electrochemical cell was an undivided parallel-plate construction with hydrodynamic calming section upstream from the electrolysis region. Electrolysis experiments were done with a recirculating continuous flow system, and were carried out in constant current mode. Product distribution was determined by gas chromatography. The product distribution was found to be independent of both electrolyte flow rate and current density, but was significantly influenced by the chloride ion concentration. Experimental data supported the reaction mechanism involving a chloronium ion intermediate.An engineering model considering the chemical environment in the electrolysis zone was developed from fundamental principles of mass transport and reaction kinetics. The model predictions agreed with experimental results, and also identified the role of the cell as the in situ generation of active chlorine.Cell current-voltage curves were recorded. The curves were found to be independent of electrolyte flow rate. Visual observations were carried out for the flow pattern inside the cell. A model was established for solution phase resistance based on this flow pattern. A cell model was constructed which took into account mass transfer, charge transfer, and ohmic resistance. The model predictions agreed well with experimental cell current-voltage curves.The cell model was applied to scale-up with minor modifications. The effects of various design and operating parameters, such as cell gap, flow rate, cell length, etc., on the cost of 1,2-dichloroethane were demonstrated. Finally, a successive quadratic programming code was applied to locate the optimal operating conditions.U of I OnlyRestricted to the U of I community idenfinitely during batch ingest of legacy ETD