7119-89-3

Organics enriched from samples of rain, snow, and glacier ice were analyzed to determine the chemical structure of the chloroorganic compounds that were most abundant in such media. Gas chromatography with atomic emission detection (GC-AED) was used to provide an overview of the presence of volatile and extractable chloroorganics at four sites in Europe and one site in Antarctica. Real samples and isomer-specific standards were then analyzed by gas chromatography with mass-spectrometric detection (GC-MS) to identify and confirm the structure of the chloroorganics that had been detected in the GC-AED analysis. The results revealed that of the volatile chloroorganics found in the samples, dichloronitromethane, a compound not previously reported to occur in the ambient environment, was often present in the highest concentration (up to 130 ng L-1). Chlorobenzenes were detected mainly as 1,4-dichlorobenzene and minor amounts of 1,3- and 1,2- dichlorobenzene and one isomer of tetrachlorobenzene (1,2,4,5- or 1,2,3,5- tetrachlorobenzene). Chlorinated alkyl phosphates, which were normally responsible for the largest peaks in the chlorine-specific chromatograms of hexane- or ether-extractable compounds, were present as tris(2- chloroethyl)phosphate, tris(1-chloro-2-propyl)phosphate, and one of the isomers bis(1-chloro-2-propyl)(3-chloro-1-propyl)phosphate er bis(1-chloro- 2-propyl)(2-chloro-1-propyl)phosphate. All of the chloroorganic compounds mentioned, i.e., dichloronitromethane, chlorobenzenes, and chlorinated alkyl phosphates, were detected at relatively remote sites in the northern hemisphere, whereas only chlorobenzenes were found in a reference sample of snow from Antarctica. Organics enriched from samples of rain, snow, and glacier ice were analyzed to determine the chemical structure of the chloroorganic compounds that were most abundant in such media. Gas chromatography with atomic emission detection (GC-AED) was used to provide an overview of the presence of volatile and extractable chloroorganics at four sites in Europe and one site in Antarctica. Real samples and isomer-specific standards were then analyzed by gas chromatography with mass-spectrometric detection (GC-MS)to identify and confirm the structure of the chloroorganics that had been detected in the GC-AED analysis. The results revealed that of the volatile chloroorganics found in the samples, dichloronitromethane, a compound not previously reported to occur in the ambient environment, was often present in the highest concentration (up to 130 ng L-1). Chlorobenzenes were detected mainly as 1,4-dichlorobenzene and minor amounts of 1,3- and 1,2-dichlorobenzene and one isomer of tetrachlorobenzene (1,2,4,5- or 1,2,3,5-tetrachlorobenzene). Chlorinated alkyl phosphates, which were normally responsible for the largest peaks in the chlorine-specific chromatograms of hexane- or ether-extractable compounds, were present as tris(2-chloroethyl)phosphate, tris(1-chloro-2-propyl)phosphate, and one of the isomers bis(1-chloro-2-propyl)(3-chloro-1-propyl)phosphate or bis(1-chloro-2-propyl)(2-chloro-1-propyl)phosphate. All of the chloroorganic compounds mentioned, i.e., dichloronitromethane, chlorobenzenes, and chlorinated alkyl phosphates, were detected at relatively remote sites in the northern hemisphere, whereas only chlorobenzenes were found in a reference sample of snow from Antarctica.

A catalytic process that provides dihalogenated nitro alcohols in up to 99% yield and with 100% atom economy is described. In situ cleavage of dihalonitroacetophenones affords nitronates that undergo Lewis acid catalyzed addition to aldehydes. Final benzoylation renders the sequence irreversible and regenerates the bond scission and acyl transfer agent.

Combined application of fumigants is a potential strategy to replace methyl bromide in the control of soil-borne pests. Unfortunately, abiotic and biotic interactions among fumigants restrict some combined application approaches. In this study, the kinetics and mechanisms of reaction between metam sodium (sodium methyldithiocarbamate) and the halogenated fumigants chloropicrin (trichloronitromethane) and 1,3-dichloropropene (1,3-D) were investigated in aqueous solution. For chloropicrin, an extremely rapid oxidation-reduction process occurred in the presence of metam sodium. The second-order rate constant for the reaction between chloropicrin and metam sodium was approximately 2 orders of magnitude greater than that for the reaction between 1,3-D isomers and metam sodium. Transformation of 1,3-D by metam sodium was associated with an aliphatic SN2 nucleophilic substitution process. The nucleophilic reaction of ci-1,3-D with metam sodium was significantly faster than that of the trans isomer and was correlated with a lower reaction activation energy for the cis isomer in the transition state. Combining Telone C-35 (65% 1,3-D and 35% chloropicrin) and metam sodium in solution might yield some nucleophilic sulfur species, which played an important role in the dissipation of 1,3-D. The incompatibility of chloropicrin and 1,3-D with metam sodium was also examined in soil under different application scenarios. Simultaneous application of metam sodium with chloropicrin or 1,3-D accelerated the transformation of the two halogenated fumigants, reducing their availability in soil. A sequential strategy for multiple fumigants was developed, which could be applied without the loss of active ingredient that occurs due to the reaction between fumigants. The proposed methodology may enhance pest control while maintaining environmental protection.

A series of chlorinated aliphatic compounds (RCI, including carbon tetrachloride (PCM), 1,1,1-trichloroethane (TCA), 1,1,2,2-tetrachloroethane (TeCA), pentachloroethane (PCA), hexachloroethane (HCA), trichloroethene (TCE), tetrachloroethene (PCE), trichloronitromethane (chloropicrin, CP), and trichloroacetonitrile (TCAN)) was reacted with ferruginuous smectite (sample SWa-1 from The Source Clays Repository), SWa, in aqueous suspension under anoxic conditions. Compounds highly polarizable or sharing substituents that facilitate charge delocalization adsorbed faster by reduced (SWa-R) than by unaltered (SWa-U) clay, indicating stronger dipole-dipole interactions between the substituents and the clay surface and/or hydrating water molecules. The reduction of the clay accelerated RCI adsorption up to 100-fold. Incubations with SWa-R promoted RCI reduction (CP, TCAN) or dehydrochlorination (TeCA and PCA). The reduction of structural Fe catalyzes the transformation of RCI via Bronsted and Lewis-basic promoted pathways. This study indicates that oxidation state of the structural Fe in SWa greatly alters surface chemistry and has a large impact on clay-organic interactions.