Date of Award
Master of Science in Chemical Engineering - (M.S.)
Chemical Engineering, Chemistry and Environmental Science
Bozzelli, Joseph W.
Wing T. Wong
We have studied the reaction of 1,2-dichloroethane with H2 in three tubular flow reactors of different diameters at atmospheric pressure in the temperature range of 550° C to 1000°C. The kinetic parameters and product distribution were experimentally determined for each size reactor. The wall and bulk reaction rate constants were decoupled via analysis of three different surface to volume reaction data.
The experimental reactor was an isothermal tubular flow reactor that operated within the domain of plug flow region. The reaction was found to follow first-order kinetics with respect to 1,2-dichloroethane when in the presence of excess hydrogen. The resulting rate constants were then used to determine the Arrhenius' plot. Activation energy and frequency factor were determined and put in the form of a reaction rate constant equation. These equations are as follows:
for d = 0.4 cm.ID k = 4.4 x 107 Exp(-32,000/RT) (1/sec)
for d = 1.05 cm.ID k = 4.6 x 107 Exp(-33,000/RT) (1/sec)
for d = 1.6 cm.ID k = 5.0 x 107 Exp(-33,000/RT) (1/sec)
For the case of a reactor with internal diameter of 1.05 cm, the GC analysis showed an appreciable conversion of 1,2-dichloroethane above 550°C. The conversion was found to be proportional to both temperature and residence time. Chlorinated by-products, which all had lesser number of chlorine atoms than the reagent, were observed to increase with temperature from 550°C to 675°C. The major chlorinated products observed were vinyl chloride and chloroethane. Trace amounts of 1,1-dichloroethane and methyl chloride were found by GC/MS analysis. When the temperature reached 700°C, the only chlorinated by-products observed was vinyl chloride. Complete destruction of 1,2-dichloroethane was observed above 850°C for residence time of 1 sec. Benzene was also observed above 800°C in very small amounts. The major products of 1,2-dichloroethane and H2 reaction were methane, ethane, ethylene, acetylene, vinyl chloride, chloroethane and HCl. The hydrocarbons production increased with temperature.
Applying the Arrhenius' equation to the values of kb and kw obtained from the equation derived by Kaufman (1), for each temperature range examined, yielded the following rate constants expressions for wall and bulk reaction:
kb = 4.8 x 107 Exp(-34,000/RT) (1/sec)
kw = 2.0 x 106 Exp(-31,000/RT) (cm./sec)
Lee, Wei-Lian, "Gas-phase reaction of 1,2-dichloroethane with hydrogen in a tubular flow reactor" (1986). Theses. 2003.