Showing papers on "Halogen published in 1974"

On the Hydrogen Bond Breaking Ability of Fluorocarbons Containing Higher Halogens

Abstract: Infrared measurements show that fluorocarbons containing higher halogens are able to open O—H---O, N—H---N, S—H---S, N—H---O=C, type hydrogen bonds. This is probably due to a competitive mechanism ...

Dielectric Breakdown Properties of SiO2 Films Grown in Halogen and Hydrogen‐Containing Environments

Abstract: Thermal oxidation of silicon, in the presence of chlorine or bromine compounds, effectively improved the dielectric breakdown characteristics (as measured with a voltage ramp) of the resulting films. At high halogen concentrations the oxidation rate was erratic; the optimal initial breakdown properties were attained by oxidizing with about one‐half of the halogen‐containing additive that would cause etching of the Si. Oxidation in the presence of halides increased the resistance of films to dielectric breakdown under accelerated bias‐temperature stressing. The maximum time to failure varied semilogarithmically with concentration and increased by 0.3 to 0.65 decade per per cent of (0–3% range) for applied fields from 2 to 7 MV/cm, respectively. Higher oxidation temperatures further improved the resistance of oxides to dielectric wear‐out. The longer wear‐out times were attributed to hydrogen rather than the halogen and could be achieved by oxidation in small concentrations of , annealing in H2, or.implantation of H2 or .

On the structure of benzene halogen complexes

Abstract: The infra-red spectra of 1 : 1 complexes between benzene and chlorine, bromine, and iodine chloride have been studied, with the complexes isolated in a nitrogen matrix at 20 K. The results are interpreted as evidence for an oblique complex structure, with the halogen molecule interacting mainly with one of the C=C bonds.

Catalytic process for copolymerizing epoxy compounds with carbon dioxide

Abstract: A catalyst composition and a process for preparing same comprising the reaction product of (a) an organo-metallic compound having the general formula R'nM, wherein n is an integer, at least one R' is an alkyl group, an alicyclic group, or halogen, hydroxy or alkoxy derivatives thereof, or hydrogen, the remaining R' groups are alkyl groups, alicyclic groups, alkaryl groups, aralkyl groups, aryl groups, or halogen, hydroxy or alkoxy derivatives thereof, and M is a metal of Group II or Group III of the periodic Table, (b) a co-catalyst component which is sulfur or a compound containing active hydrogen atoms, and (c) carbon dioxide. The catalyst composition is used in preparing copolymers of epoxy compounds with carbon dioxide.

A Radiation-Induced Bonding of Iodine at the Surface of Uniform Polystyrene Particles

Abstract: At a population of 1.4 X 1012 particles of 0.234-um diameter cc-', the yield of surfacebonded halogen in 5 X 10-4 M iodide corresponds to 0.02 iodine atoms bonded to the particle surface per 100 eV of total energy absorbed. In 5 X 10-4 M iodide, the reaction rate is proportional to the surface area and depends upon the first power of the radiation intensity. The experimental results are consistent with a reaction mechanism in which radical sites are produced on the particle surface by reaction of OH and other radicals from the bulk phase. A surface bonding of iodine results from a reaction of these sites with halogen intermediates formed in the aqueous phase, predominantly by reaction of OH radicals with iodide. Energy absorbed in the particle apparently plays no major role in the reaction, and a complex dependence of the reaction upon the iodide concentration suggests that a surface adsorption of halogen intermediates plays an important role in the reaction.

Process for sterilizing water by the combination of chlorine and another halogen

Abstract: For water disinfection or sterilization, for instance of drinking, municipal waste, industrial or swimming-pool waters, there is introduced in a reactor a mixture of chlorine and of a salt of another halogen (bromine and/or iodine) in such conditions that mainly free halogen and hypohalogenous acid of said other halogen are produced; the mixture is supplied to the water, in such amounts that, an halogenated residual capable of destroying microbial contamination in the system, is maintained

Process for preparing halogen-substituted aromatic polycarbonates

Abstract: of the Disclosure A process is provided for making high molecular weight halo-substituted aromatic polycarbonates in a phase boundary reaction in which an o,o,o',o'-tetrahalogenobisphenol and phosgene are reacted in an aqueous medium at a pH of 7 to 9 in the presence of from 2 mol% to 20 mol% catalyst in a first step and the resulting product is polycondensed at a pH at least about 13 in a second step.

Reactive scattering of alkali dimers: chemi-ionization

Abstract: Measurements of total cross sections Qi for chemi-ionization in scattering of a K2 dimer beam by a range of halogen containing molecules, at translational energies E ∼ 7–11 kcal mol-1, are reported Substantial cross sections, Qi ∼ 2–10 A2 are exhibited by the halogen molecules Br2, ICl, IBr, I2 Distinctly lower values Qi ∼ 0·1–02 A2 are exhibited by BrCN and the mercuric and stannic halides, HgX2, SnX4 The results show a close correlation with the chemi-ionization exoergicities, particularly for formation of a K+,X- ion pair These chemi-ionization data and results from previous reactive scattering studies are compared, in order to estimate relative reaction yields for different reaction paths The reaction dynamics for K2 with halogen molecules and cyanohalides are rationalized in terms of the electronic structure of the potential surface, where the orientation of the K2 dimer plays a crucial role

Substituted 4-benzylquinolines

Abstract: The present invention relates to compounds of the formula: ##SPC1## Wherein R 1 is alkyl, R 2 and R 3 are hydrogen, halogen, alkyl, alkoxy, hydroxy, or methylenedioxy, and R 4 and R 5 are hydrogen, halogen, alkyl, alkoxy, hydroxy, or methylenedioxy and pharmaceutically acceptable salts thereof. These compounds are useful as antianginal agents.

Process for preparing aromatic polymers in presence of alkali metal fluoride

Abstract: An aromatic polymer comprising recurring units having the formula --Ar--Q-- is made by a new process which comprises heating an alkali metal fluoride with an activated halophenol of the formula X--Ar--QH and/or a substantially equimolar mixture of an activated dihalobenzenoid compound of the formula X--Ar--X and a dihydric phenol of the formula HQ--Ar--QH in which formulae Ar and Q are respectively a bivalent aromatic residue and an oxygen or sulphur atom and may vary from unit to unit in the polymer chain and X is a halogen atom, the amount of alkali metal fluoride being such that together with any of the X atoms that are fluorine the total number of fluorine atoms in the reaction system is at least twice the number of --QH groups in the system.

ANTI-INFLAMMATORY STEROIDS OF THE ANDROSTANE SERIES HAVING A HALO-SUBSTITUTED C -C ALKOXY CARBONYL GROUP AT THE 17β POSITION

Abstract: The Specification describes compounds of the general formula Wherein X represents a hydrogen, chlorine or fluorine atom; R1 represents a β-hydroxy group, an oxo group or (when X is a chlorine atom) a β-chlorine atom; R2 represents a hydrogen atom, a methylene group or an α- or β-methyl group; R3 represents a hydrogen atom or C1-4 alkyl or phenyl group; R4 represents a methyl group substituted by at least one halogen atom; an ethyl group substituted by at least one fluorine and/or iodine atom; or a propyl group substituted by at least one halogen atom; and represents a single or double bond. The Specification also describes processes for the preparation of compounds of formula I as well as pharmaceutical compositions containing such compounds. The compounds of formula I have good anti-inflammatory activity, particularly on topical application.

9-Substituted 3-aminocarbazole compounds

Abstract: Novel 3-aminocarbazole compounds of the formula: ##SPC1## Wherein X is hydrogen or halogen, Y is oxygen or represents two hydrogen atoms; and R1 and R2, which can be the same or different, are hydrogen, lower alkyl or hydroxyalkyl or amino; and n is 1 or 2, with the proviso that when n is 2, X, Y, R1 and R2 cannot all be hydrogen atoms, As well as the salts thereof with inorganic and organic acids; are outstandingly effective indicators for the determination of glucose and provide stable compositions for such glucose determination.

Reaction of halogens with oxide surfaces

Abstract: Charge transfer reactions at oxide surfaces are discussed for the halogens, chlorine, bromine and iodine as strong electron acceptors. Adsorption of chlorine and bromine on MgO prepared in vacuo is characterised by the appearance of a band at 430 nm in the diffuse reflectance spectrum and an e.s.r. signal with g-factors of 2.0099 and 2.0020. These features are destroyed on heating and oxygen is evolved. Chlorine and bromine react with the lattice oxygen ions to give halide ions corresponding to about 20 and 10% respectively of the surface MgO ion pairs; no evidence of the formation of molecular X–2 ions was obtained. These results can be understood in terms of the initial formation of charge deficient groups of oxygen ions, such as On–n and subsequent release of oxygen. The reaction of bromine with MgO would not be expected purely on a consideration of the bulk heats of formation, and indicates an appreciable concentration of surface oxygen ions with less than 5-fold co-ordination. Iodine, as expected from the low heat of formation of the iodide, does not displace oxygen ions on the surface but some iodide ions are formed. All the halogens are able to displace oxygen adsorbed as O–2 from the surface indicating that this ion is only weakly bonded to the surface.

Synthesis of 2,6-Naphthyridine, 4-Methyl-2,6-naphthyridine, and their Derivatives

Abstract: A detailed outline of the experimental procedures for the synthesis of 2,6-naphthyridine and 4-methyl-2,6-naphthyridine is given. Cyclization of 2-(4-cyano-3-pyridyl)propionitrile with anhydrous hydrogen bromide lead to 3-amino-4-methyl-2,6-naphthyridine which was transformed into 4-methyl-2,6-naphthyridine in a series of reactions. The u.v. spectra of 2,6- and 4-methyl-2,6-naphthyridine and their amino and halogen derivatives were recorded.

Bromine-containing cyclic phosphonic acid esters

Abstract: Bromine-containing phosphonic acid esters of the formula ##EQU1## in which R represents a halogen-containing linear or branched aliphatic or cycloaliphatic hydrocarbon radical having from 1 to 8 carbon atoms and R' and R" are hydrogen, halogen or alkyl groups having from 1 to 4 carbon atoms which may be closed to form a ring and/or substituted by halogen, at least one substituent being a bromine atom, are suitable as flame retardants for plastic materials, especially polystyrene and styrene copolymers.

Thermal decomposition of dibenz[b,d]iodolium and 10H-dibenz[b,e]-iodininium halides. Evidence for a homolytic pathway from halogen scrambling, hydrogen transfer, and trapping

Abstract: The thermal decomposition of dibenz[b,d]iodolium halides and 10H-dibenz[b,e]iodininium halides has been examined. Observation of products of halogen scrambling and hydrogen transfer suggested a radical mechanism involving 2′-iodobiphenyl-2-yl and 2-(2-iodobenzyl)phenyl radicals. Results of trapping experiments with an acetylenic ester suggested the involvment of a biphenyl diradical.

Reactions of halogens with hydrogen halides. Studies in the Cl2 + HBr system

Abstract: The following net processes occur in a system containing chlorine and hydrogen bromide: These reactions have been followed spectrophotometrically in a gas phase stopped flow apparatus. The first two reactions are strongly surface catalyzed on untreated glass or quartz, but are much slower if the cell surface has been covered with silicone and photochlorinated. Rates in such systems are first order in each reactant, and comparable limiting rate constants have been obtained in cells with different methods of preparing the surfaces and with different surface-to-volume ratios. These experimental rate constants must be equal to or greater than those of the homogeneous bimolecular reactions. Then limiting rate constants at 35°C in liters per mole per second are k1 ≤ 0.8, k2 ≤ 15, and k3 ≤ 0.04. Reactions of HI with Cl2, Br2, and ICl are all much faster than reaction (2). These observations and those of other diatomic molecule reactions can be rationalized if halogen and hydrogen halide molecules react through a transition state in which the hydrogen atom is near the center of a triangle of three halogen atoms.

Halogen-substituted benzimidazolone compounds

Abstract: New chlorinated and/or brominated N,N'-substituted benzimidazolones are obtained by reacting N,N'-substituted benzimidazolones with chlorine or bromine. The new chlorine-containing and/or bromine-containing benzimidazolone compounds are suitable for the production of heat-stable, flame-resistant polymers.