Molecular interaction, co-solubilization of organic pollutants and ecotoxicity of a potential carcinogenic fuel additive MTBE in water

Abstract

We study the molecular properties and ecological consequences of a most common gasoline oxygenate, and widespread carcinogenic environmental threat, methyl tert-butyl ether (MTBE) upon inclusion in water. Our study shows the change of bulk properties like densities, viscosities and refractive indices of binary mixtures of water and MTBE at temperatures from 10°C to 50°C and over the entire composition range, under atmospheric pressure using densimetry, viscometry and refractive index measurement. The studies are clear indicative of the association of MTBE in the hydrogen bonding network and possible MTBE clustering in the aqueous solution. While, dynamic light scattering studies confirm the formation of micro-droplets (micelle-like) of MTBE in water, which still persist at 70°C (much above the boiling point of pure MTBE, 55.2°C), FTIR and Raman spectroscopies have distinctly unrevealed the molecular interaction of MTBE with water molecules. Co-solubilization of other potential hazardous organic matters (anthracene, naphthalene, benzo[α]pyrene and 4-(dicyanomethylene)-2-methyl-6-(p-dimethylamino-styryl)-4H-pyran (DCM)) in the MTBE–water mixture has also been studied. Raman spectroscopic studies confirm the micelle-like cluster of MTBE to be a potential host of the organic pollutants in the aqueous environments. The picosecond-resolved spectroscopic studies also confirm localization of DCM in the ground state, in the MTBE cluster. Our studies also show the ecotoxic effect of MTBE in model eukaryotic microorganism yeast in aqueous environments.