The Temperature Dependence of Band Maxima Molar Absorptivities of the Carbon-Halogen Stretching Mode in Tertiary Butyl Chloride, Bromide, and Iodide in the Liquid Phase

Abstract

The absorbances at the peak maxima of the carbon-halogen stretching mode of t-butyl chloride, bromide, and iodide have been measured as a function of temperature. With the use of corrected concentration and pathlengths, these data have been converted into molar absorptivities at the respective peak maxima. The data have then been analyzed statistically for the purpose of developing a mathematical model for the dependency of molar absorptivity, at these peak maxima, on the absolute temperature. In all three cases, a linear relationship of the form e = XT + Y was found to satisfactorily fit the data. The molar absorptivity of all three band maxima decreases approximately 1% per Kelvin. This result indicates that attempts to apply Beer's law at temperatures other than that used to derive the constants will lead to significant error if the temperatures differ by more than a few degrees.