John H. Penn and Richard D. OR West Virginia University, Morgantown, WV 26506 The past 25 years has seen a dramatic increase in the understanding and in the utilization of modern photochemistry. Polymerization (I),energy storage (21, semiconductors for electronic photocopying (3), organic synthesis (4), in addition to the more traditional areas of photography and instant photography (5)attest to the large number of lightinitiated processes in everyday use. In spite of the large number of areas of photochemical applications, the teaching of photochemical theory and experimental technique have rarely worked their way into the general curriculum. The reasons for this lack of photochemical curricula may include the seemine comwlexitv of manv" whotochemical reaction . mechanisms, the high initial cost of equipment, safety, and lack of education of photochemical reaction types and general techniques for performing photochemical experiments. We have been attempting to develop both new experiments and laboratory equipment suitabl' for the undergraduate chemistry teaching laboratory so that the introduction of photochemical experiments into the chemical curriculum may occur more easily. Key ingredients to the introduction of any experiment into the undergraduate chemistry laboratory include the initial expense of the required equipment and the safety of the experiment. Recent developments in microscale glassware have been shown to be advantaeeous on both counts (6. . . 7). Chemical acquisition and disposal costs are minimized in the microscale approach by the requirements for smaller amounts of reagents and solvents. Safety is also enhanced by microscale glassware, since smaller amounts of chemicals minimize exposure to potentially hazardous material and the risk of explosion.
86
Journal of Chemical Education
In this document. we rewort the develooment of a microscale glassware photochen;ical immersionAwellthat incorporates all of the traditional advantaees of microscale elassware as well as offers significant de&opments for the pedagogy of organic photochemistry. These advantages include low cost (5$400), low risk of exposure to UV radiation and/ or ozone, and potential utilization of all of the photochemical reaction techniques that are available on the larger more traditional immersion well designs. Our design is shown in the figure. In order to maintain a small size, we have selected a UVP Model 11-SC-l Hg Lamp with its associated SCT-1 power supply.' This lamp was chosen because it emits the highest UV output for a lamp of its size and cost. A high radiant output intensity is desirable, since the "apparent rate" of a photochemical reaction is dependent on the light intensity. The lamp is relatively cheap, being available at costs
