Propanol to Propane: An Advanced Laboratory Experiment Using Heterogeneous Catalysts for Two Successive Gas-Phase Reactions

Abstract

This article describes two organic reactions involving gas-phase heterogeneous catalysis suitable for use as an advanced undergraduate synthesis and spectroscopy laboratory experiment. In the first reaction, 2-propanol is converted to propene using heated alumina beads as the catalyst. The product gas is purified with a dry ice–propanol cold trap. In the second reaction, the propene is hydrogenated to propane using a palladium catalyst in nearly 100% yield. Both propene and propane are characterized by proton nuclear magnetic resonance spectroscopy and both give elegant spectra that are ideally suited for interpretation by undergraduate students. Students may use proton decoupling to assign the spectrum and COSY to confirm chemical shift assignments. This laboratory experiment is original in that gas-phase organic reactions are not usually experienced in chemistry laboratory programs. The experiment demonstrates continuous-flow, closed-system gas phase reactions of fundamental importance in chemical industry.

Demonstration of the Influence of Specific Surface Area on Reaction Rate in Heterogeneous Catalysis

“…It is not easy to make a live demonstration showing the influence of the number of active sites on the catalytic reaction rate during lectures in an ordinary lecture hall. There are several examples of heterogeneous catalytic reactions that are simple enough for such classroom demonstrations, i.e., catalytic oxidation of alcohols, ammonia, , acetone, and sulfur dioxide; reduction of alcohols; , and variations on the decomposition of hydrogen peroxide, such as H 2 O 2 decomposition catalyzed by manganese dioxide, transition metals, or Cr 2 O 7 2– adsorbed on solids . Those experiments allow demonstration of the heterogeneous catalysis phenomenon but are not suitable for quantitative analysis of the influence of the number of active sites (which is directly proportional to the specific surface area) on the reaction rate.…”