Search results for "Chlorine"

Comparative electrochemical treatments of two chlorinated aliphatic hydrocarbons. Time course of the main reaction by-products.

2011

The chlorinated aliphatic hydrocarbons conjugate toxicity with high chemical stability, bioaccumulation and long-range diffusivity. Chloroethanes are particularly ubiquitous in the industry and in household products, and their entry to the environment may entail potential risks for the living beings. At present, the US Environmental Protection Agency is carrying out the Endocrine Disruptor Screening Program (EDSP), where 1,2-dichloroethane (DCA) and 1,1,2,2-tetrachloroethane (TCA) are considered as priorities for their potential effects on the endocrine system. DCA is also found in the list of priority substances drawn up by the European Commission. To avoid the release of chloroethanes int…

Chloroterpenes and other organochlorines in Baltic, Finnish and Arctic wildlife

1991

Abstract Chloroterpene mixtures were analyzed as toxaphene (TOX) in Baltic, Finnish and Arctic fish, seal and bird samples together with DDT residues, hexachlorocyclohexanes (HCH), hexachlorobenzene (HCBz), chlordanes, hexachloronaphthalenes (HxCN), PCBs, PCDDs and PCDFs. TOX was found to be the most globally (evenly) distributed organochlorine compound in Scandinavia, thus far. TOX seemed to bioaccumulate significantly in fish but not in predatory birds in Finland.

Swimming pool water--fractionation and genotoxicological characterization of organic constituents.

2005

Swimming pool water treatment in general includes flocculation, sand filtration, and subsequent disinfection with chlorine. The continuous chlorination and input of organic material by bathers in combination with recirculation of the pool water leads to an accumulation of disinfection by-products (DBPs) in the water. Several DBPs have been identified as human carcinogens and are thought to cause allergic asthma. Therefore, the elimination of DBPs is one major aim of pool water treatment. Using membrane filtration as an alternative treatment technology, DBPs can be removed more efficiently than with conventional treatment. In this study membrane filtration and genotoxicity testing were appli…

Chlorination of p-cymene by chlorine in carbon tetrachloride: Model compounds for environmental analyses

1989

p-Cymene was chlorinated by chlorine in CCl4. The products of the chlorination were separated by distillation and purified by preparative gas chromatography. The structures of chlorocompounds were confirmed by means of their NMR and mass spectra. The distillation gave as the main compounds: (2) 2-chloro-, (4) 2,3-dichloro-, (5) 2,5-dichloro-, (6) 2,3,6-trichloro-, (7) 2,3,5,6-tetrachloro-p-cymenes and as by-products: (8) 2,5,7-trichloro-p-cymene, (9) 2,6-dichloro-1-methyl-4-(1-methylethenyl)benzene (cymenene), and (10) 2,3,6-trichloro-1-methyl-4-(1-methylethenyl)benzene (cymenene).

2-(N,N-Diethylaminomethyl)-6,7-trihydroquinolinyl-8-ylideneamine-Ni(ii) chlorides: application in ethylene dimerization and trimerization

2020

A series of Ni(II) complexes with the general formula [2-((NEt2)Me)-8-{N(Ar)}C9H8N]NiCl2, where Ar = 2,6-Me2C6H3 in Ni1, 2,6-Et2C6H3 in Ni2, 2,6-i-Pr2C6H3 in Ni3, 2,4,6-Me3C6H2 in Ni4, 2,6-Et2-4-MeC6H2 in Ni5, and 2,4,6-t-Bu3C6H2 in Ni6, has been prepared using a one-pot reaction of 2-(N,N-diethylaminomethyl)-6,7-dihydroquinolin-8(5H)-one with the corresponding aniline and nickel dichloride hexahydrate. The resultant complexes were characterized using elemental analysis and FT-IR spectroscopy, while the mononuclear Ni1 and Ni3 were also the subject of single-crystal X-ray diffraction study. On activation with MMAO, the complexes Ni1–Ni6 displayed good activity in ethylene oligomerization, f…

Calibrated international standards including ATHO-G, T1-G, and VG-568 (USNM 72854)

2021

Water Depollution by Advanced Oxidation Technologies

2020

This chapter deals with water treatments by advanced oxidation processes (AOPs) based on chemical and photochemical reactions. The most used processes are described, and for each of them, the main reaction mechanisms, principles, advantages, drawbacks, performances and formation of by-products, coupled with technologies and their applications to waters and wastewater depollution, have been analysed, supporting the main results of studies published in the pertinent literature.

Pairwise effects of chlorine substituents on the13C NMR chemical shifts of dichlorobicyclo[2.2.1]heptanes (norbornanes)

1984

The 13C NMR spectra of nine dichlorinated bicyclo[2.2.1]heptanes (norbornanes) have been measured and assigned. The pairwise effects of chlorine substituents which cause deviations from the additivity of single-substituent effects were investigated and are discussed. The largest effect found is the high-field shift of carbons bearing vicinal cis substituents. In the case of geminal substitution deviations from additivity were found to be to low field and large in the γ, smaller in the β and negligible in the α chemical shifts. The observed deviations for 1,3-disubstituted cases vary from −3.2 to +1.1 ppm at different carbons, allowing no simple explanation. Replacement of α-hydrogen in a di…

Electrochemical treatment of wastewater contaminated by organics and containing chlorides: Effect of operative parameters on the abatement of organic…

2022

Abstract In the last years, large attention has been devoted to the electrochemical treatment of wastewater polluted by recalcitrant organics and containing chlorides. However, the utilization on an applicative scale of this route is limited by the fact that usually it is not possible to achieve high removals of organics without the generation of significant amounts of chlorinated by-products. Here, the role of several operative parameters on the performances of the process was systematically evaluated using phenol as a model organic pollutant. It was shown that the removal of phenol and TOC and the generation of many by-products including chlorophenols, chloroacetic acids, chlorate and per…

Electrochemical treatment of aqueous solutions containing one or many organic pollutants at boron doped diamond anodes. Theoretical modeling and expe…

2012

The electrochemical oxidation of organics in water at boron doped diamonds (BDD) was experimentally investigated with the aim to discuss the correlations among the conversion of the pollutants and the instantaneous current efficiency ICE with the operative conditions. A simple theoretical model previously developed for the oxidation of oxalic acid accounting for the cases of mass transfer control, oxidation reaction control and mixed kinetic regimes was adopted and extended to challenge its predictive capability in the case of organics of different nature and in systems with more pollutants. A quite good agreement, between theoretical predictions and experimental data pertaining to the elec…