A Study of the Photochemical Reactions between Chlorine and Propene Gases

The chlorine and propene gases will process addition reaction under the irradiation of UV light:

We have built up a vacuum system in order to study the reaction mechanism. We fill chlorine gas and propene gas individually into two different stainless steel tanks, and then fill in nitrogen gas to the ratio we want. In order to control the partial pressure of chlorine and propene gases in the reaction cell, two mass flow meters are used to control the flow rate of both of them. A mercury lamp with a band-width filter is the light source, and makes the wave length of the UV light which passes through the reaction cell be about the maximum absorption near the bond energy of a chlorine molecule. So we can generate the chlorine radical to react with propene. Then the products pass through a potassium carbonate column that can trap the hydrogen chloride molecule generated in the reaction. After that, a low-temperature trap (about –80℃) is used to collect the products. The collected products are analysised by the proton-NMR. In addition to the experiment, we use the theoretical calculation software (Gaussian 03) to calculate the probable molecules in the reaction mechanism by the density functional theory with different basis sets. And compare the results with our experiments.