关键词: 汽油, 共轭二烯烃, 二烯值, 极谱法, 分析方法

Abstract: The determination of conjugated dienes content in gasoline by polarographic method is studied. Using N’N-dimethylformamide containing 0.02 mol•L-1 tetrabutylammonium iodide as supporting electrolyte, when sweeping the gasoline sample at potential range of -2.10V~-2.85V, peaks at -2.45V and -2.80V are observed. It is identified that the peak at -2.45V is styrene or naphthalene, and the peak at -2.80V is conjugated dienes. Using 1,3-pentadiene as standard conjugated diene, the calibration curve is linear in the concentration range of 5.0×10-5～3.8×10-4 mol•L-1 for determining the content of conjugated dienes in gasoline, and the correlation coefficient is 0.998 4. As compared with the conventional maleic anhydride method, this method is fast, simple, repeatable, and it can be used to fuel containing alcohol.

Key words: gasoline, conjugated dienes, diene value, polarography, analytical method