Showing papers on "Halogen published in 2001"

Hydrogen produced from hydrohalic acid solutions by a two-electron mixed-valence photocatalyst.

Abstract: Energy conversion cycles are aimed at driving unfavorable, small-molecule activation reactions with a photon harnessed by a transition metal complex. A challenge that has occupied researchers for several decades is to create molecular photocatalysts to promote the production of hydrogen from homogeneous solution. We now report the use of a two-electron mixed-valence dirhodium compound to photocatalyze the reduction of hydrohalic acid to hydrogen. In this cycle, photons break two RhII–X bonds of a LRh0–RhIIX2 core in the presence of a halogen trap to regenerate the active LRh0–Rh0 catalyst, which reacts with hydrohalic acid to produce hydrogen.

Fluorine-containing materials and processes

Abstract: Chemical precursors that contain carbon atoms and fluorine atoms can be activated under a variety of conditions to deposit fluorine-containing materials. Chemical precursors of the formula (F 3 C) 4−m−n MX m R n , are preferred, wherein M is Si or Ge; X is halogen; R is H or D; m is 0, 1, 2 or 3; and n is 0, 1, 2, or 3; with the proviso that (m+n)≦3.

Competition of hydrogen-bond acceptors for the strong carboxyl donor

Abstract: A database study on the competition of hydrogen-bond acceptors for the strong carboxyl donor in crystals is reported. The relative success in attracting this donor is determined for 34 types of acceptor (O, N, S, halogen and π acceptors), and a correlation between the success in competition and the average hydrogen-bond distance is established.

Epoxy resin composition and semiconductor device

Abstract: The present invention provides an epoxy resin composition for encapsulation of semiconductors which contains substantially neither halogen-based flame retarding agents nor antimony compounds and is excellent in moldability, flame retardance, high-temperature storage characteristics, reliability for moisture resistance, and solder cracking resistance. That is, the present invention is an epoxy resin composition for encapsulating semiconductors which contains (A) an epoxy resin, (B) a phenolic resin, (C) a curing accelerator, (D) an inorganic filler and (E) a phosphazene compound as essential components, the total weight of phosphate ion and phosphite ion contained in the phosphazene compound being not more than 500 ppm. Further, the epoxy resin composition may optionally contain a flame-retarding assistant or an ion scavenger.

Molecular dynamics simulation of silicon and silicon dioxide etching by energetic halogen beams

Abstract: Molecular dynamics simulations of silicon (Si) and silicon dioxide (SiO2) etching by energetic halogen (fluorine or chlorine) atoms in the energy range of 50–150 eV are performed using new sets of interatomic potentials for Si–O–F and Si–O–Cl systems. Etch rates and selectivities obtained from numerical simulations are compared with available experimental data. Etching mechanisms in the atomic scale, especially the difference between chlorine and fluorine direct ion etching characteristics, are discussed on the basis of the simulation results.

Determination of F, Cl, and Br in Solid Organic Compounds by Laser-Induced Plasma Spectroscopy

Abstract: The feasibility of using laser-induced plasma spectroscopy (LIPS) as a rapid and simple method to analyze fluorine, chlorine, and bromine in solid organic compounds was investigated. A Nd:YAG laser at 1064 nm with pulse energy of 100 mJ was used to produce the plasma. This method presents many advantages for the determination of halogens in organic compounds, including very simple sample preparation and near-real-time analysis. Solid organic compounds were measured in air and helium atmospheres. Carbon in organic compounds was chosen as the internal standard for the measurement of F, Cl, and Br. Linear responses for these elements were obtained for both atmospheres. However, the sensitivity was much higher and the background noise was much lower in the helium atmosphere.

Electrolysis cell for generating chlorine dioxide

Abstract: A method for making chlorine dioxide, by passing an aqueous feed solution comprising sodium chlorite into a non-membrane electrolysis cell comprising an anode and a cathode, adjacent to the anode, while flowing electrical current between the anode and the cathode to electrolyze the aqueous feed solution and convert the halogen dioxide salt to halogen dioxide. The anode is preferably a porous anode through which the aqueous feed solution passes to maximize the conversion of chlorite to chlorine dioxide.

Chemical and electrochemical synthesis of homopolymer and copolymers of 3-methoxyethoxythiophene with aniline, thiophene and pyrrole for studies of their gas and vapour sensing

Abstract: Herein we report chemical and electrochemical formation of poly(3-methoxyethoxythiophene) and its copolymers with aniline, thiophene and pyrrole which give highly conducting polymeric materials. These are soluble in common organic solvents in the conducting state. The response mechanism of these compounds, to a selection of gases and vapours, was investigated using two techniques: measurement of conductance and mass changes using a four probe method and X-ray fluorescence (XRF) device, respectively. Prepared films were exposed to hydrogen halides, hydrogen cyanide, halogens, monochloroacetic acid (MCAA), 1-3-5 trichloromethylbenzene (TCMB), methylbenzyl bromide (MBB), bromoacetone (BA) and cyanogen bromide (CB). These gas sensors may have advantages compared to other sensors in their ability to operate at room temperature, low concentration, stability in air, sufficient diffusion and their selectivity. Copyright © 2001 John Wiley & Sons, Ltd.

Thermal Chemistry of C3 Allyl Groups on Pt(111)

Abstract: The thermal chemistry of allyl iodide and of allyl bromide adsorbed on Pt(111) was investigated by temperature-programmed desorption (TPD) and reflection−absorption infrared (RAIRS) spectroscopies. On the clean Pt(111) surface, both allyls were found to bond to the surface via the halogen atom in a gauche conformation and with the C−C−C plane close to parallel to the surface. In the presence of surface hydrogen, allyl iodide was found to tilt backward such that the C−C−C plane adopts a more vertical orientation on the surface; in this more upright geometry, both cis and gauche isomers were identified. With both molecules the facile thermally activated cleavage of the carbon−halogen bond results in the formation of C3 allylic species on the surface. A η1 allylic moiety was identified by RAIRS in the high-exposure regime of allyl iodide after annealing to 200 K, and the formation of a second η3 allylic intermediate was inferred from TPD experiments with coadsorbed hydrogen and deuterium. At low surface conc...

Alkylindium subhalides derived from the tetrahedral indium(I) cluster compound [In4[C(SiMe3)3]4].

Abstract: Partial oxidation of the tetraalkyltetraindium(I) compound In4[C(SiMe3)3]4] 1 with halogen donors such as 1,2-dibromoethane and hexachloroethane or with mixtures of bromine and aluminum tribromide afforded novel alkylindium halides in which the indium atoms still possess unusually low oxidation states. Indium-indium single bonds between bivalent indium atoms were found in the compounds In2X2R2 (R = C(SiMe3)3, X = Cl (2) or Br (4)), which gave dimers in the solid state with all four halogen atoms in a bridging position. The tetrahedral arrangement of four indium atoms in a cluster was retained in the compound In4Br2R4 (3), in which one bromine atom occupied a mu3-bridging position above one triangular face of the In4 tetrahedron. One edge of that triangle was bridged by the second bromine atom. Mixed-valent indium atoms resulted with an average oxidation state of + 1.5.

Colored composition containing phthalocyanine compound, ink for ink jet recording, ink jet recording method, and method for improving resistance to fading due to ozone gas

Abstract: PROBLEM TO BE SOLVED: To provide a new phthalocyanine compound, an ink used for ink jet recording and giving an image excellent in color hue and having high fastnesses to light and ozone gas, an ink jet recording method, colored compositions used for an ink sheet for thermal recording, a color toner for electrophotography and a color filter for an image pickup device, and a method for enhancing the resistance of an image to an oxidizing environment such as an atmosphere of ozone. SOLUTION: The phthalocyanine compound is represented by general formula 1 (wherein R1 to R8 are each H, halogen or the like; and W1 to W4 are each any one of R1 to R8 , or a sulfonylsulfamoyl group, or an acylsulfamoyl group, provided that one or more of W1 to W4 comprise groups having both an electron attracting group with a Hammett substituent constant of 0.20 or higher and one or more ionic hydrophilic groups) and has an association material absorption stronger than a monomer absorption on the spectral absorption curve. The colored compositions contain the phthalocyanine compound.

Catalysts for polymerization of α-olefins, process for producing α-olefin polymers, novel transition metal compounds and catalyst components for polymerization of α-olefin

Abstract: Catalysts for polymerization of α-olefin, composed of a transition metal compound, an inorganic silicate or an ion exchangeable layer compound other than silicate, and optionally an organoaluminum compound, are described. The transition metal compound is represented by formula (I): where A1 and A2 are each independently a conjugated 5-membered ring ligand provided that A1 and A2 may be the same or different in a molecule, and at least one of A1 and A2 forms a 7- to 10-membered condensed ring including two adjacent carbon atoms of the conjugated 5-membered ring, which condensed ring is formed by joining two adjacent substitutent groups on the conjugated 5-membered ring; Q is a bridging group of the two conjugated 5-membered rings of A1 and A2 at optional positions of the 5-membered rings; M is a metal atom selected from elements of Group 4-6 of the Periodic Table; and X and Z are each independently a hydrogen atom, a halogen atom, a hydrocarbon group, and amino group, a halogenated hydrocarbon group, an oxygen-containing hydrocarbon group, a nitrogen-containing hydrocarbon group, a phosphorus-containing hydrocarbon group or a silicon-containing hydrocarbon group.

Process for producing trifluoromethylbenzylamines

Abstract: The present invention relates to a process for producing a trifluoromethylbenzylamine represented by the general formula (1), where R1 represents hydrogen atom, a halogen atom selected from the group consisting of fluorine, chlorine, bromine and iodine, or trifluoromethyl group. This process includes the step of reducing an oxime by hydrogen in an organic solvent in the presence of a catalyst and ammonia. The oxime is represented by the general formula (2), where R1 is defined as above, and R2 represents hydrogen atom, an alkyl group or an aralkyl group. With this process, the trifluoromethylbenzylamine can be produced with high yield.

Anticholinergics, processes for preparing them, and pharmaceutical compositions containing them

Abstract: A compound of formula 1 wherein: A is a group selected from X− is an anion with a single negative charge; R1 and R2 are each independently a C1-C4-alkyl optionally substituted with hydroxy or halogen; and R3, R4, R5, R6, R7, and R8 are each independently hydrogen, C1-C4-alkyl, C1-C4-alkyloxy, hydroxy, CF3, CN, NO2, or halogen, with the proviso that at least one of the groups R3, R4, R5, R6, R7, and R8 is not hydrogen, processes for preparing these compounds, pharmaceutical compositions containing these compounds, and their use as pharmaceutical compositions.

Microbiological control in animal processing

Abstract: Fecal bacterial contamination in an animal is reduced by providing it with drinking water containing a microbiocidally-effective amount of halogen-based microbiocide resulting from mixing with water (A) a product formed in water from (i) bromine, chlorine, or bromine chloride, or any two or more thereof, (ii) a water-soluble source of sulfamate anion, and (iii) a water-soluble base; (B) at least one 1,3-dihalo-5,5-dialkylhydantoin in which one of the halogen atoms is a chlorine atom and the other is a chlorine or bromine atom, and in which each alkyl group, independently, contains in the range of 1 to about 4 carbon atoms; (C) at least one 1,3-dibromo-5,5-dialkylhydantoin in which one of the alkyl groups is a methyl group and the other alkyl group contains in the range of 1 to about 4 carbon atoms; or (D) any two or more of (A), (B), and (C).

A halopyrrole ligand for use in a catalyst system

Abstract: A pyrrole ligand for an olefin oligomerisation catalyst system wherein the pyrrole ligand incorporates a halogen source and wherein the ligand is a halopyrrole or a derivative thereof. The halopyrrole may be a halopyrrole-containing compound. The halopyrrole-containing compound of the present invention is any pyrrole derivative of general formula X-(CH2)n-C4H4N, where X can be a halide selected from the group consisting of fluoride, chloride, bromide and/or iodide, and n can be any number greater than 0. Typical halopyrrole-containing compounds of the invention have from about 4 to about 20 carbon atoms per molecule. The halopyrrole-containing compounds include derivatives of pyrrole having a bromoalkyl group bonded to the pyrrole ring.

Compound having difluoroalkoxy at its terminal, liquid crystal composition and liquid crystal display element

Abstract: PROBLEM TO BE SOLVED: To provide a liquid crystal compound large in the absolute value of Δe, relatively low in viscosity, having relatively large Δn and showing good compatibility even to a low temperature, a low voltage drivable composition and a liquid a crystal display element using the same. SOLUTION: The liquid crystal compound is represented by formula (1) (wherein, R is an alkyl, R is hydrogen, a halogen, cyano or alkyl, rings A to A are each independently trans-1,4-cyclohexylene, 1,4'-cyclohexenylene or 1,4-phenylene, Z to Z are each independently a single bond, -CH2 CH2 -, -CH2 O-, -OCH2 -, -COO-, -OCO-, -CH=CH, -CF2 O- or -OCF2 -, Y to Y are each independently hydrogen or fluorine but Y is not fluorine, Y is not hydrogen and Y is not hydrogen and l and m are each independently 0 or 1).

Process for preparing organochlorosilanes by dehydrohalogenative coupling reaction of alkyl halides with chlorosilanes

Abstract: The present invention relates to a process for preparing organochlorosilanes and more particularly, to the process for preparing organochlorosilanes of formula I by a dehydrohalogenative coupling of hydrochlorosilanes of formula II with organic halides of formula III in the presence of quaternary phosphonium salt as a catalyst to provide better economical matter and yield compared with conventional methods, because only catalytic amount of phosphonium chloride is required and the catalyst can be separated from the reaction mixture and recycled easily, wherein R1 represents hydrogen, chloro, or methyl; X represents chloro or bromo; R2 is selected from the group consisting of C1-17 alkyl, C1-10 fluorinated alkyl with partial or full fluorination, C2-5 alkenyl, silyl containing alkyl group represented by (CH2)nSiMe3-mClm wherein n is an integer of 0 to 2 and m is an integer of 0 to 3, aromatic group represented by Ar(R′)q wherein Ar is C6-14 aromatic hydrocarbon, R′ is C1-4 alkyl, halogen, alkoxy, or vinyl, and q is an integer of 0 to 5, haloalkyl group represented by (CH2)pX wherein p is an integer of 1 to 9 and X is chloro or bromo, and aromatic hydrocarbon represented by ArCH2X wherein Ar is C6-14 aromatic hydrocarbons and X is a chloro or bromo; R3 is hydrogen, C1-6 alkyl, aromatic group represented by Ar(R′)q wherein Ar is C6-14 aromatic hydrocarbon, R′ is C1-4 alkyl, halogen, alkoxy, or vinyl, and q is an integer of 0 to 5; and R4 in formula I is the same as R2 in formula III and further, R4 can also be (CH2)pSiR1Cl2 or ArCH2SiR1Cl2, when R2 in formula III is (CH2)pX or ArCH2X, which is formed from the coupling reaction of X—(CH2)p+1—X or XCH2ArCH2X with the compounds of formula II; or when R2 and R3 are covalently bonded to each other to form a cyclic compounds of cyclopentyl or cyclohexyl group, R3 and R4 are also covalently bonded to each other in the same fashion.

Mechanism of the hydrolysis of halogen nitrates in small water clusters studied by electronic structure methods.

Abstract: High-level electronic structure calculations have been used to study the mechanism of the hydrolysis of bromine nitrate in neutral water clusters containing one to eight solvating water molecules. The calculations clarify some of the uncertainties in the mechanism of halogen nitrate hydrolysis on PSC ice aerosols. The free energy barrier decreases from 42.4 kcal mol-1 (single water) to essentially zero when catalyzed by six water molecules. As the size of the water cluster is increased, BrONO2 shows increasing ionization along the Br−ONO2 bond, consistent with the proposed predissociation in which the electrophilicity of the bromine atom is enhanced, thus making it more susceptible to nucleophilic attack from a surface water molecule. A species akin to the experimentally proposed intermediate, H2OBr+NO3-, is found to be stable in clusters containing both three and six water molecules, where the ion pair is separated by single and double layers of water molecules, respectively. For a cluster containing six...

Photoinitiator mixtures and compositions with alkylphenylbisacylphosphine oxides

Abstract: Compounds of the formula I in which R1 is C1-C4alkyl, R2 is hydrogen, C1-C4alkyl or C1-C4alkoxy and R3, R4, R5, R6 and R7 independently of one another are hydrogen, halogen, C1-C20alkyl, cyclopentyl, cyclohexyl, C2-C12alkenyl, C2-C18alkyl which is interrupted by one or more oxygen atoms, or are phenyl-substituted C1-C4alkyl, or are phenyl which is unsubstituted or is mono- or disubstituted by C1-C4alkyl and/or C1-C4alkoxy, with the provisos that at least one of the radicals R3, R4, R5, R6 and R7 is other than hydrogen and that, if R1 and R2 are methyl, R3 and R6 are not methyl, and mixtures of such compounds with α-hydroxy ketones, benzophenones and α-amino ketones, are suitable as photoinitiators.

Reactions at Solid−Liquid Interfaces. The Mechanism and Kinetics of the Fluorination of 2,4-Dinitrochlorobenzene Using Solid Potassium Fluoride in Dimethylformamide

Abstract: The halogen exchange reaction of 2,4-dichloronitrobenzene with potassium fluoride in dimethylformamide containing tetrabutylammonium salts has been studied employing an electrochemical detection methodology based upon the use of square wave voltammetry to follow the loss of reactant and the formation of the product and intermediates. The results obtained show that the kinetics of loss of parent material behave on one hand as a dissolution-rate-controlled process and on the other as a homogeneous chemical process. Initially homogeneous reaction dominates the observed kinetics as the presaturated solution is stripped of fluoride ion; at longer time, the observed kinetics are controlled by the rate of KF dissolution. Modeling the system using a fully implicit finite difference method with Richtmyer modification (FIRM algorithm) yielded a mean value for the homogeneous rate constant for the formation of 2,4-dinitrofluorobenzene by reaction of 2,4-dichloronitrobenzene with fluoride ion in DMF at 85 °C of 640 ±...

Stabilization of halogen-containing compounds, especially liquid crystal compounds, by addition of a 4-substituted 2,6-di-tertiary butyl-phenol, itself having liquid crystal-type units

Abstract: Stabilization of halogen-containing compounds is effected by addition of a 4-substituted 2,6-di-tert butyl-phenol Stabilization of halogen-containing compounds is effected by addition of a 4-substituted 2,6-di-tert butyl-phenol of formula (I) R = H, 1-12C alkyl or alkoxy (optionally substituted once by -CN or -CF3 or once or more by halogen), -CN, -NCS, -OCN, -NO2, halogen, -OCF3 or -OCHF2; A = a single bond, cis- or trans-1,4-cyclohexylene, 1,4-phenylene or 1,4-cyclohex-3-enylene, with each of these groups optionally having 1-4 H atoms replaced by F and/or Cl; Z = -CH2CH2-, -HC=CH-, -C equivalent to C-, -C(O)O-, -CF2O-, -OCF2- or -CF2CF2-; and n = 0, 1, 2 or 3