Abstract:
Petroleum products are usually coloured with dyes, which can be natural or synthetic. In Nigeria, a number of plants serve as a source of dyes. Among these are Rothmenia hispidia, Pterocarpus osun and Terminalia superba. In the present work, the seeds of Rothmenia hispidia were extracted with water using cold maceration method, while the stem wood of Pterocarpus osun and Terminalia superba were extracted with ethanol. The extracts of Rothmenia hispidia were isolated by sedimentation whereas those of Pterocarpus osun and Terminalia superba were isolated by simple distillation. Petroleum products (gasoline, diesel, kerosene and wax) were coloured with the aqueous extract of Rothmenia hispidia and ethanol extracts of Pterocarpus osun and Terminalia superba. The dyes gave the products beautiful colours ranging from yellow through orange to red. Consequently, application of these dyes in petroleum products will serve for aesthetic purposes, identification of different petroleum fractions as well as trademark. The UV-Visible and Infrared Spectroscopy of the dyes were also determined