Infrared Analysis of α-Olefin

Infrared analysis has been employed for the quantitative determination of α-content in normal α-olefin. In these usual methods no standardized sample has been determined by other methods without infrared analysis, accordingly only the approximate values were determined. Therefore, it was necessary to determine the purity of infrared-pure α-olefin by the use of other methods. For the purpose the authors applied a reductive ozonolysis. The reductive ozonolysis was carried out for infrared-pure 1-octadecene, obtained by pyrolysis of octadecyl acetate, and the ozonolysis products of which were aldehydes and ketones cloven at the double bonds and were analysed by gas liquid chromatography.As a result, 97.7% (average) of the heptadecyl aldehyde and little amount of C16, C15 and C11 fatty aldehydes and C15 ketone were found in the reductive ozonolysis products. The α-content of 1-octadecene was 97.7%, for the heptadecyl aldehyde corresponds to α-olefin, and standard deviation of this value was 0.43%.This standardized sample was used in the infrared analysis, and the absorptivities of the characteristic α-olefin bands at 10.10μ and 11.00μ were 38.0 and 124.1 respectively. These absorptivities gave satisfactory results for the determination of α-contents in various octadecenes.