Reaction of N,N-Dialkylcarboxamides with Halogens

N,N-Dialkylcarboxamides react with halogens in the absence of water to form complexes which are likely to have an ionic structure with the Hlg⁺ ion coordinated at the carbonyl oxygen atom. These products can be isolated as individual compounds. Complexes with bromine undergo further transformations to afford bis-dialkylamide hydrogen tribromide and the corresponding -bromo amide. When the reaction is carried out in the presence of water, the products are only bis-dialkylamide hydrogen tribromides; here, the N-alkyl groups act as a source of protons.     

Reaction of N,N,N',N'-Tetramethyloxamide with Bromine

Reaction of bromine with N,N,N',N'-tetramethyloxamide results in dibromobromate of 3-methyl-5-dimethylimmoniooxazolidin-4-one (in an open system) and in dibromobromate of 4,5,-dibromo-1,3-dimethylimidazolium (in a closed system).     

Effect of heat treatment on α-ZnS and β-ZnS transformations

There remains no doubt today about the effect which the crystallographic structure of zinc sulfide, used for the preparation of electroluminophors, has on its optical and electrical-properties. A study of this effect is extraordinarily difficult, inasmuch as α-ZnS ? β-ZnS phase transitions are accompanied by the formation of intermediate phases, with a variety of disorder patterns and of polytypes, which in turn affects the distribution and the buildup of glow centers. Available test data pertaining to the relation between electroluminescence characteristics and the structure of zinc sulfide are far from exhaustive and often contradictory. Thus, while the authors of [1] find the intensity of electroluminescence to be minimum within the regions of structural distortions, these regions becoming luminescent at higher voltages than regions with cubic or hexagonal structures, the authors of [2, 3] emphasize that a higher intensity of electroluminescence is due to defects responsible for the formation of glow centers and that it is in these regions where the activator atoms are mainly concentrated. In this study the authors have set out to trace the changes in α-ZnS and β-ZnS concentration during heat treatment, inasmuch as such a treatment affects all electroluminescence characteristics.     

Organotrihalide Complexes: α-Nucleophiles and Effective Oxidizing Agents in Decomposition Reactions of Organophosphorus Compounds in Water and Surfactant Micelles

We have studied the nucleophilic and oxidative reactivity of the system HOBr/BrO^–, in water and in the presence of different types of surfactants, relative to 4-nitrophenyldiethylphosphate, 4-nitrophenyl- 4´-toluenesulfonate (nucleophilic substitution), and 4-nitrophenol (oxidation). As the source of "active" bromine, we used organotrihalide complexes. The micellar effects of the surfactants in nucleophilic substitution reactions are adequately described within both a pseudophase distribution model and an ion-exchange model. Just transferring the reaction from water to micelles of a cationic surfactant leads to an increase in the observed rates of reaction of the BrO^– ion with esters by up to a factor of 20-30 and an increase in the rate for reaction of HOBr with nitrophenol by up to a factor of 5, while the HOBr/BrO^– system is one of the most effective systems in decomposition of organophosphorus compounds.     

Reversible dissociation of dibromobromates in organic solvents

A study was carried out on the reversible decomposition of dibromobromate anions in organic solvents and we found the equilibrium constants for the processes responsible for the distribution of active halogen and hydrogen halide between their different forms in solution. The capacity of the solvent to form hydrogen bonds with the bromide anion, the feasibility of forming a molecular complex with bromine, and the structure of the cation (in solutions with low ionizing capacity) were all found to affect the reversible decomposition of the dibromobromate anion. Translated from Teoreticheskaya i éksperimental'naya Khimiya, Vol. 44, No. 5, pp. 298–305, September–October, 2008.