Reaction of methyl hypochlorite with certain olefins in the presence of boron trifluoride

Fluoro chlorides are major products in the reaction of methyl hypochlorite with certain olefins in the presence of boron trifluoride.     

Reaction of halogens with some α,β-unsaturated aldehydes and ketones

Mechanisms are proposed to account for evidence indicating that some simple α,β-unsaturated aldehydes and ketones do not react with halogens by the expected attack on the CC bond.     

Radical additions of xenon difluoride to cis- and trans-1-phenylpropenes: comparison with trichloramine and iodobenzene dichloride

We would like to report data which support a free radical pathway for reaction of xenon difluoride (XeF₂) with alkenes in organic solvent. Radical intermediates have been proposed for reaction of XeF₂ to double bonds. For example, a radical pathway was suggested for the gas phase reaction of XeF₂ to ethylene and propene [1]. Zupan speculated on a radical cation pathway for the acid catalyzed reaction of XeF₂ with alkenes but gave no experimental evidence for this mechanism [2,3]. Radical cation intermediates were demonstrated for the reaction of XeF₂ to aromatics by Filler [4]. Acid catalyzed ionic reactions to unsaturated hydrocarbons have been reviewed [5].Zupan and Pollak have shown that alkenes do not react in aprotic solvent with XeF₂ at low concentrations of alkene unless acid catalyst is present [3]. However, we observed that illumination of a dilute solution of $\text{cis-}$ or $\text{trans}$-1-phenylpropenes (I) or (II) in methylene chloride at 0° with a 270 watt sunlamp produced IIIa and IIIb in less then two hours (Table). Furthermore, at high concentration of (I) and (II), a spontaneous reaction occurred in the dark between XeF₂ and these styrenes. The reaction conditions for both of these reactions imply a radical mechanism — the latter a molecule-induced pathway.     

Quantification of organic contaminants in urban stormwater by isotope dilution and liquid chromatography-tandem mass spectrometry

Pollutants transported in urban stormwater runoff induce pervasive water quality degradation in receiving waters. To accurately characterize stormwater quality and treatment system performance across the range of possible contaminant characteristics, comprehensive multi-residue analytical methods are necessary. Here, we developed a solid-phase extraction (SPE) and high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) method to quantify representative stormwater-derived organic contaminants across multiple chemical classes, including vehicle-related chemicals, corrosion inhibitors, industrial chemicals, pesticides, pharmaceuticals and personal care products, and antioxidants. Extraction conditions, isotope-labeled internal standards, and LC-MS/MS parameters were optimized to enhance recovery, minimize matrix effects, and maximize selectivity and sensitivity. The developed method was sensitive (method quantification limits < 10 ng/L for > 80% of selected analytes) and accurate (mean relative recoveries in the range of 70–130%, with relative standard deviations < 25% for 77% of the analytes) for most of the analytes. The method was used to analyze samples collected from nine urban watersheds during a storm event; 62% of the 39 analytes were detected at least once at concentrations up to 540 ng/L (1,3-diphenylguanidine). Spatial trends in detection and concentration were observed for vehicle-related and industrial chemicals that correlated with vehicle traffic. Total concentrations of pesticides suggested that residential uses could be more important sources than agriculture. This study illustrates the pervasive occurrence of a wide variety of stormwater-derived chemicals in urban receiving waters and highlights the need to better understand their environmental fate and ecological implications.

Graphical abstract