Synthesis of marker dyes from salicylaldehyde and aromatic amines

Abstract

Marker dyes were synthesized from salicylaldebyde and amine by preparing imine compounds and allowing them react with diazonium salts of aniline derivatives having different substituents. These syntheric marker dyes could be detected by extracting them with a solution of 20% ethylenediamine in propylene glycol. The marker dyes could be added into diesel oil at usable levels of 1-10 parts per million (ppm) without imparting any color to the naked eyes. Quantitative determination of these marker dyes was accomplished using UV/VIS spectroscopy with 97.4% recovery of the extracted marker dye. The effects of marker dye on physical properties of marked diesel oil were also studied using ASTM test methods. As a result, the marker dye was found to have no effect on the physical properties of diesel oil. Moreover, these marker dyes were stable in diesel oil for at least three. Accordingly, these synthetic marker dyes had good potential to be used as marker in diesel oil.