An Experiment in Applied Optics: Determination of the Kinetics of the Oxidation of an Organic Dye
Abstract
An effective, inexpensive experiment that demonstrates the utility of applied optics as a process monitor and diagnostic in chemistry/chemical engineering. The global kinetics of the oxidation of ordinary food color by household bleach are determined by using optical absorption. A square cross section clear plastic container contains a well-stirred batch mixture of water, blue or green food color, and household bleach through which is passed a helium-neon laser beam. The intensity of the transmitted beam is monitored over time with a photodiode detector connected to a chart recorder or other signal detection device. Transmission curves are generated as functions of the initial volumes of bleach added to a fixed volume of water. Modeling of the data suggests an oxidation rate that is first order in dye and first order in bleach.
