Showing papers on "Halide published in 1995"

Components and catalysts for the polymerization of olefins

Abstract: Components of bimetallic catalysts for the polymerization of olefins comprising a compound of a transition metal M selected from Ti, V, Zr and Hf containing at least one M-π bond, a compound of Ti or V not containing metal-π bonds and a support comprising a magnesium halide. The catalysts obtained from the components of the invention are particularly suitable for gas-phase polymerization processes.

Hydraulic fracturing process and compositions

Abstract: Viscoelastic surfactant based aqueous fluid systems are described that are useful in fracturing subterranean formations penetrated by a wellbore. The preferred thickening agents are quaternary ammonium halide salts derived from certain waxes, fats and oils. The thickening agent is used in conjunction with an inorganic water soluble salt such as ammonium chloride or potassium chloride, and an organic stabilizing additive selected from the group of organic salts such as sodium salicylate. The resulting fluids are stable to a fluid temperature of about 225° F.

X-ray diffraction studies of ordered chloride and bromide monolayers at the Au(111)-solution interface.

Abstract: We present in situ surface x-ray scattering observations of ordered chloride and bromide monolayers on Au(111) electrodes in aqueous solutions as an example of in situ x-ray diffraction from adsorbates of the lighter elements (Z50). At a critical surface density both halides form incommensurate, hexagonal-close-packed monolayers that compress uniformly with increasing potential. Our structural results provide quantitative data on the residual adsorbate charge, the two-dimensional melting, and the two-dimensional compressibilities of halide monolayers.

Carbocationic catalysts and process for using said catalysts

Abstract: A living carbocationic catalyst composition comprising an initiator of a tertiary alkyl halide, a tertiary aralkyl halide or polymeric halide a co-initiator of a methylaluminum or methylboron compound, and a solvent medium with a dielectric constant between 2.5 and 7 is used to produce narrow molecular weight distribution polymers particularly isobutylene polymers.

Photographic Sensitivity: Theory and Mechanisms

Abstract: 1. Silver halide photographic materials 2. Structure and preparation of silver halide grains 3. Physical properties of silver halides 4. Mechanisms of latent image formation 5. Spectral sensitization 6. Chemical sensitization and stabilization 7. Development-amplification of latent image 8. Future prospects for silver halide photography

Homogeneous Hydrogenation of Carbon Dioxide to Methanol Catalyzed by Ruthenium Cluster Anions in the Presence of Halide Anions

Abstract: Methanol, together with methane, is formed for the first time by homogeneous hydrogenation of CO2 using a catalytic system consisting of Ru3(CO)12 and alkaline iodides in N-methylpyrrolidone (NMP) solution at 240 °C. The time course of the reaction indicates the successive formation of CO, methanol, and then methane. The FT-IR analysis of the resulting reaction solutions reveals the formation of several species of ruthenium carbonyl anion and their mutual interchanges during the reaction. A mechanism for the overall reaction is proposed, based on these results.

Stereoselective Anion Template Effects: Syntheses and Molecular Structures of Tetraphenyl [12]Mercuracarborand-4 Complexes of Halide Ions

Abstract: The synthesis and characterization of the chloride and iodide ion complexes of a set of isomeric hydrophobic tetraphenyl ( 12lmercuracarborand-4 hosts having sterically encumbered cavities are described. These compounds ((3-C6Hs-1,2-C2B10H9Hg)4) *XLi (3*XLi, X = C1- and I-) were prepared by the reaction of the corresponding mercuric halides with cZoso-3-Ph-l,2-Liz-1,2-C2BloHg. The presence of phenyl substituents in this system requires the existence of isomers in which the phenyl substituents are arrayed about the periphery of the host cavity. Three of four possible stereoisomers of the chloride ion complex were detected by HPLC analysis of the reaction mixtures,

Composite reverse osmosis membrane

Abstract: A composite reverse osmosis membrane comprising a thin film and a microporous substrate as a support therefor, said thin film mainly comprising a crosslinked polyamide obtained by the interfacial polymerization of (a) an amine component comprising at least one monomeric amine compound having at least two primary or/and secondary amino groups and (b) an acid halide component which is either a benzenehexacarbonyl halide or a mixture of a benzenehexacarbonyl halide with a monomeric acid halide compound having at least two acid halide groups. The composite reverse osmosis membrane exhibits high water permeability and high desalting performance even when used at a low operation pressure of, e.g., 5 kgf/cm 2 .

Method of making metals and other elements

Abstract: A method of producing a non-metal element or a metal or an alloy thereof from a halide or mixtures thereof. The halide or mixtures thereof are contacted with a stream of liquid alkali metal or alkaline earth metal or mixtures thereof in sufficient quantity to convert the halide to the non-metal or the metal or alloy and to maintain the temperature of the reactants at a temperature lower than the lesser of the boiling point of the alkali or alkaline earth metal at atmospheric pressure or the sintering temperature of the produced non-metal or metal or alloy. A continuous method is disclosed, particularly applicable to titanium.

Catalytic composition and process for the alkylation of aliphatic hydrocarbons

Abstract: The invention concerns a catalytic composition resulting from mixing at least one aluminum halide, at least one quaternary ammonium halide and/or at least one amine halohydrate and at least one cuprous compound, preferable a halide. The invention also concerns a process for the alkylation of isoparaffins by olefins with that composition.

Methyl halide hydrolysis rates in natural waters

Abstract: International regulations are under consideration for methyl bromide because of its high time dependent ozone depletion potential. Geocycling of the species is not well understood, and removal may occur in several types of natural water incuding the oceanic and those in soils. The hydrolysis reaction is a dominant loss pathway in environmental aqueous systems, but rate constants have generally been reported only in distilled water and at greater than room temperature. Here we present measurements in sodium chloride solutions and in seawater in addition to pure water, and at temperatures across the oceanographic range. The reaction could be followed even in solutions near the freezing point because product methanol was monitored in the method of initial rates. Time constants for methyl bromide hydrolysis fall between 10 and 1000 days over the temperatures of the sea, and are always within an order of magnitude of the fastest abiotic destruction mode, chlorination. Activation energies for the two processes are similar so that the ratio of their time scales does not vary with oceanic location. Hydrolysis rate constants are also listed for the closely related compounds methyls iodide and chloride. Solvolysis of the methyl halides in natural waters acts as a source of methanol to the ocean and atmosphere.

Titanium nitride and multilayers formed by chemical vapor deposition of titanium halides

Abstract: A gaseous mixture of a titanium halide and silane is introduced to a plasma or thermal CVD reactor to induce a reaction such that a conformal and pure titanium film is deposited onto a semiconductor device within the reactor. The titanium halide has a chemical form of TiX 4 , where X is a halogen. Other gaseous combinations of the titanium halide, ammonia, hydrogen, a halogen and silane are subjected to plasma or thermal CVD to induce a reaction to deposit titanium silicide and titanium nitride films onto the semiconductor device. Successive CVD processes create bilayers of TiSi x /TiN or Ti/TiN, and/or trilayers of TiSi x /Ti/TiN onto the semiconductor device.

A PA-CVD PROCESS FOR DEPOSITION OF A SOLID METAL-CONTAINING FILM ONTO A SUBSTRATE CONTAINING AT LEAST 50 % of Fe or WC

Abstract: A new plasma assisted chemical vapour deposition (PA-CVD) process for deposition of a solid metal-containing film onto the surface of a substrate containing at least 50 % of Fe or WC (such as hard metal or steel), by which the metallic component of the metal-containing film is introduced into the system as a metal halide, is disclosed. The new process involves shifting the process gas composition between a high and a low metal halide level, whereby the adhesion of the deposited film to the substrate is improved.

Spectral and electrochemical anion sensing by a novel 5,10,15,20-tetrakis(R-substituted) porphyrin receptor (R = C6H4NHC(O)C5H4CoC5H5+PF6–)

Abstract: A novel 5,10,15,20-tetrakis(R-substituted) porphyrin receptor molecule (R = C6H4NHC(O)C5H4CoC5H5+ PF6–)3 is prepared and is shown to spectrally and electrochemically sense halide, nitrate, hydrogen sulfate and dihydrogen phosphate guest anions.

Catalytic composition and aliphatic hydrocarbon alkylation process

Abstract: The catalytic compsn. comprises at least one of each of the following: aluminium halide, quat. ammonium halide and/or amine halo-hydrate and a cuprous cpd.. Also claimed is the use of the compsn. in the alkylation of iso-paraffins with olefins.

Method for producing halogenated products from metal halide feeds

Abstract: A method and apparatus producing halogenated products from metal halide feeds. In one embodiment, uranium hexafluoride is treated by separating fluorine from the metal of the uranium hexafluoride. Uranium hexafluoride is introduced into a molten metal bath under conditions whereby the uranium hexafluoride in the presence of hydrogen and oxygen can react to form a uranium dioxide and anhydrous hydrogen fluoride. The anhydrous hydrogen fluoride is removed from the molten metal bath as a gas stream and the uranium dioxide is discharged as a ceramic phase.

PROCESS FOR PREPARING IMPROVED TiO2 BY SILICON HALIDE ADDITION

Abstract: A process for producing substantially anatase-free TiO2 by addition of a silicon halide in a reaction of TiCl4 and an oxygen-containing gas in a plug flow reactor is disclosed. Pigmentary properties such as gloss and CBU are enhanced without loss of durability.