نتایج جستجو برای: bromine
تعداد نتایج: 2325 فیلتر نتایج به سال:
Strong Raman scattering is observed from iodine anions adsorbed at ca. 3% coverage on single layer graphene. In addition, the Raman signal from just one bromine intercalation layer inside three and four layer thick graphenes is observed. We analyze and model the intramolecular electronic, charge-transfer, and multiple reflection electromagnetic mechanisms responsible for this unusual sensitivit...
The disinfective power of chlorine, bromine, and mixtures of chlorine and bromine at different ratios was compared. The influence of pH was also studied. The experiments were carried out in "purified" water and in natural waters of swimming pools, river, and sea. In the presence of high amounts of nitrogenous growth-promoting material (at neutral pH), bromine was more effective than chlorine; i...
Halogens in the troposphere are increasingly recognized as playing an important role for atmospheric chemistry, and possibly climate. Bromine and iodine react catalytically to destroy ozone (O3), oxidize mercury, and modify oxidative capacity that is relevant for the lifetime of greenhouse gases. Most of the tropospheric O3 and methane (CH4) loss occurs at tropical latitudes. Here we report sim...
Studies on the germicidal activity of chlorine, bromine, and iodine were made by use of the Association of Official Agricultural Chemists official first action method for determining effectiveness of swimming pool water disinfectants. In this procedure, 0.3 ppm of available chlorine as chlorine gas has activity equivalent to 0.6 ppm of available chlorine in the buffered sodium hypochlorite cont...
hexamethylenetetramine-bromine on wet alumina rapidly regenerates carbonyl compounds from their corresponding semicarbazone using microwave under solventless system.
A visible-light-induced photoredox-catalyzed bromoetherification of alkenols is described. This approach, with CBr4 as the bromine source through generation of bromine in situ, provides a mild and operationally simple access to the synthesis of β-bromotetrahydrofurans and -tetrahydropyrans with high efficiency and regioselectivity.
Aryl-bromine bonds are successfully cleaved by cobalt(II) porphyrins in basic media to give Co(por)Ar (por = porphyrin) in good yields. Mechanistic studies suggested that the aryl-bromine bond is cleaved through a halogen atom transfer mechanism, which is different from the aryl-halogen bond cleavage mechanism with other group 9 metalloporphyrins.
Regioselective bromine-lithium exchange reactions on polybrominated biaryls enable the modular synthesis of various polysubstituted biphenyls such as bis(dialkylphosphino)-, bis(diarylphosphino)- and dialkyl(diaryl)phosphinobiphenyls. All permutations of substituents at the ortho positions of the biphenyls are possible. In a similar manner, one can gain access to monophosphine analogues. So far...
Halogens are strongly enriched in peat and peatlands and such they are one of their largest active terrestrial reservoir. The enrichment of halogens in peat is mainly attributed to the formation of organohalogens and climatically controlled humification processes. However, little is known about release of halogens from the peat substrate and the distribution of halogens in the peat pore water. ...
in an environmentally benign solventless system, alcohols are rapidly oxidized to carbonyl compounds using hexamethylenetetramine-bromine on wet alumina under microwave irradiation.
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