Polymer-supported and polymeric quinones were synthesized and evaluated in their ability to dehydrogenate ethylbenzene in the vapor phase. The polymeric quinones were found to be more useful agents for dehydrogenation than the polymer-supported quinones, probably due to the higher concentration of quinone per given mass of polymer.
The factors that affected the yield of styrene using the polymeric quinone were the nature of the polymer, the space velocity in the column, and the reaction temperature. The space velocity was evaluated by holding constant the flow rate of the carrier gas and varying the concentration of ethylbenzene in the gas stream. The best yields were obtained by introducing 0.25 ml of reactant into the column every ten minutes. Using this process the yield of styrene varied from 2.73% at 200°C to 6.90% at 250°C. Both nitrogen and air were used as the carrier gas in this process, and there was no significant difference in the yield of styrene. However, the ability of air to re-oxidize the quinone or its tendency to form undesirable oxidation by-products was not evaluated.
The effect on the ease of vapor-phase dehydrogenation of adding an electron-donating or an electron-withdrawing substituent to ethylbenzene was evaluated. The electrondonating substituent appeared to have little effect upon the dehydrogenation, but the electron-withdrawing substituent had a negative effect.
| Identifer | oai:union.ndltd.org:WKU/oai:digitalcommons.wku.edu:theses-3721 |
| Date | 01 July 1986 |
| Creators | Pickard, Simeon |
| Publisher | TopSCHOLAR® |
| Source Sets | Western Kentucky University Theses |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | Masters Theses & Specialist Projects |
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