Abstract: An alkali pre-washing for determination of bromine number of mid-low temperature coal tar was established, by which the interference of phenols in the coal tar on bromine number could be avoided. The influence of phenols on the determination of bromine number was investigated and determined by model compounds. The phenolic and olefin model compounds were used to investigate the phenol removal rate and the standard recovery, respectively. The removal of phenols reaches 100% by the alkali pre-washing method. For actual samples this rate is greater than 97.0%. The standard addition recovery is greater than 96.8% and the relative standard deviation is less than 2.0%. The oil phase and water phase cross little after pretreatment.

Key words: coal tar, bromine number, phenols, alkali washing