Bromoform

Abstract: Halogenated hydrocarbons are members of priority water contaminants because of their negative health and environmental impacts. In this study, the solubility of three halogenated hydrocarbons, namely, carbon tetrachloride, chloroform, and bromoform was measured in 12 hydrophobic ionic liquids (ILs) for temperature ranging between 25 and 45 °C. We investigated the chemical structure and alkyl chain length effect of three different cations (piperidinium, pyrrolidinium, and ammonium-based) paired with bis(trifluoromethylsulfonyl)imide anion. It was found that carbon tetrachloride and bromoform are partially miscible in all tested ILs while chloroform exhibits full miscibility. For ammonium based ionic liquids, the solubility increases with the increase of the cation molecular weight and alkyl chain length. The results indicate that the solubility of the studied halogenated hydrocarbons in methyltrioctylammonium bis(trifluoromethylsulfonyl)imide, octyltriethylammonium bis(trifluoromethylsulfonyl)imide, and 1-...

Abstract: The solvent shifts of haloformic protons, (Cl3CH, Br3CH, I3CH), have been measured in 24 n-electron donor solvents consisting of halogenated hydrocarbons, esters, ketones, ethers and amines. Deviations of ΔBr and Δ1 from linear dependence with ΔCl are indicative of the presence of halogen bond formation competitive with hydrogen bonding interactions. Bromoform interacts predominantly by hydrogen bonding, halogen bonding being detected to a small extent in chlorinated hydrocarbons and amines. Iodoform shows halogen bonding interactions which increase in relative importance to hydrogen bonding with solvent basicity. Halogen bonding is predominant for solutions of iodoform in amines.

Abstract: Groundwater resources in California represent a confluence of high-risk factors for hexavalent chromium contamination as a result of industrial activities, natural geology, and, potentially, land use. Here, we examine state-wide links in California between groundwater Cr­(VI) concentrations and chemicals that provide signatures for source attribution. In environmental monitoring wells, Cr­(VI) had the highest co-occurrence and also clustered with 1,4-dioxane and several chlorinated hydrocarbons indicative of the metal plating industry. Additionally, hotspots of Cr­(VI) co-occurring with bromoform result from volatile organic compound remediation using in situ chemical oxidation that inadvertently oxidizes naturally occurring Cr­(III). In groundwater supply wells, which are typically free of industrial inputs, Cr­(VI) correlates with dichlorodiphenyldichloroethylene (DDE), vanadium, and ammonia and clusters with nitrate and dissolved oxygen, suggesting potential links between agricultural activities and Cr­(VI). Specific controls on Cr­(VI) vary substantially by region: from the metal plating industry around Los Angeles and the San Francisco Bay areas to natural redox conditions along flow paths in the Mojave Desert and to correlations with agricultural practices in the Central Valley of California. While industrial uses of Cr lead to the most acute cases of groundwater Cr­(VI) contamination, oxidation of naturally occurring Cr affects a larger area, more wells, and a greater number of people throughout California.