Showing papers on "Chlorine published in 1975"

Reactive ion etching of aluminum

Abstract: A process for etching aluminum wherein a masked layer of aluminum, supported on a substrate, is exposed to a plasma formed by imposing an RF voltage across at least two spaced electrodes in an ambient including a gas selected from the group consisting of CCl4, Cl2, Br2, HCl. The resultant conditions provide a reactive environment where the aluminum is bombarded with chlorine or bromine ions. The aluminum reacts with chlorine or bromine ions to form an aluminum chloride or bromide compound, which is volatile at the temperature of the sputtered substrate.

Method of inhibiting scale formation

Abstract: Novel compositions comprising calcium hypochlorite and a proportion of a polyacrylic acid compound have been produced. the compositions provide accurately controlled concentrations of available chlorine to bodies of water such as swimming pools by reducing the solubility off the calcium hypochlorite. In addition, when employing dispensers for water soluble chemicals in treating very hard or highly alkaline water, inhibition of scale formation and prevention of scale build-up in the dispenser is achieved when the novel compositions are used.

Method of sanitizing a volume of water in conjunction with chlorine

Abstract: A method of sanitizing a volume of water, such as a swimming pool, in conjunction with chlorine, and a bromine-containing material which in the presence of water is adapted to release the bromine, as available bromine, the quantities of the added material being determined relative to the pH of the water prior to such addition, two materials being provided, one being used when the pH of the water is below a predetermined figure and the other being employed when the pH is above a predetermined figure, the respective materials being adapted to bring the pH of the water to a predetermined value and at the same time provide available bromine, the materials involved employing a bromo-organic compound and either an alkaline or acidic reactive material, the latter being present in excess to that required to effect the desired conversion of the bromine, with the respective materials being present in relative quantities adapted to effect the desired control of the pH and simultaneously provide a predetermined halogen content which may be utilized in conjunction with the addition of available chlorine into the water to bring the total halogen content to a desired level.

Method of electrolysis of brine

Abstract: Disclosed is a method of electrolyzing alkali metal chloride brine in an electrolytic cell having an anolyte chamber containing an anode and a catholyte chamber containing a steel cathode, separated from the anolyte chamber by an asbestos diaphragm. Brine is fed to the anode chamber, a voltage is imposed across the cell, chlorine is evolved at the anode, and hydrogen is evolved at the cathode. According to the disclosed method, the hydrogen overvoltage is reduced by feeding an hydroxy carboxylic acid to the electrolytic cell. Additionally, a phosphorous containing compound and a surfactant may be added to the cell to further reduce the hydrogen overvoltage.

Daunomycin analogues, their preparation and use

Abstract: Daunomycin analogues of the formula: ##STR1## wherein when each R 1 is hydrogen, each R is hydrogen, chlorine, bromine, methyl or methoxy and when each R 1 is chlorine, bromine or methyl, each R is hydrogen, are useful in treating various mammalian tumors and are prepared by reacting a daunomycinone derivative of the formula: ##STR2## wherein R and R 1 are as defined above with 1-chloro-2,3,6-trideoxy-3-trifluoroacetamido-4-trifluoroacetoxy-α-L-lyxopyranose in an inert anhydrous organic solvent in the presence of a catalyst and a hydrogen chloride acceptor.

Removal of low level hardness impurities from brine feed to chlorine cells

Abstract: Brine from a conventional treatment process is pre-filtered prior to the electrolysis of same by a method which includes the steps of: (a) heating the brine, (b) adding sodium carbonate thereto, (c) stirring the solution, (d) allowing the solution to settle, and (e) passing the solution through an absolute membrane filter. The filter "polishes" the brine feed by removing the high hardness ions.

System for improving charge efficiency of a zinc-chloride battery

Abstract: A system is provided for improving the charge efficiency of a zinc-chloride battery by reducing the chlorine concentration on charge in a flowing electrolyte system by desorbing chlorine from the flowing electrolyte under reduced pressure and removing the desorbed chlorine from the electrolyte flow loop.

A Comparative Study of the Effect of Phosphorus and Chlorine in Urethane and Isocyanurate-Urethane Foams

Abstract: I n recent years there has been a growing tendency of increasing the thermal stability of many polymer systems and, whenever possible, to impart flame resistance with low smoke evolution. For urethanes, this tendency has become of vital importance, especially in the manufacture of cellular, rigid urethanes for applications in construction, transportation and insulation of equipment requiring maintenance at elevated temperatures. Conventional methods for improving flame resistance of rigid urethane foams include the addition of a phosphorus and/or halogen containing compounds either in the form of an additive, a reactive component, or, to a lesser degree, in the form of a protective coating. Major research emphasis has shifted to flame-resistant compositions which are integral parts of the urethane chemical structure. These, of course, can be utilized by either the one-shot or prepolymer methods in the preparation of foams. Disadvantages of these types of cellular urethanes are relatively high smoke evolution, limited heat resistance, and in many cases, reduced hydrolytic stability. Hence, recent trends in the development of low flammability urethane foams have been based on copolymers containing heat-resistant groups, such as isocyanurates, oxazolidones, carbodiimides, and cyclic imides (1-22). The isocyanurate ring is thermally more stable than the urethane group, due to the absence of labile hydrogen. Isocyanurates, free of basic or

Method of analyzing residual chlorine

Abstract: A continuous analyzer for accurately measuring the free chlorine residual in a chlorinated water supply having an ammonia content which gives rise to a combined chlorine residual whose bactericidal effectiveness is poor as compared to free chlorine. The analyzer includes an amperometric cell through which a sample from the supply is conducted, the cell being provided with a measuring electrode and a counter electrode. Connected in series with the electrodes is an external voltage source whose level is set to impress a potential on the measuring electrode at which the current flow in the cell as a result of the chlorine content of the sample increases progressively in accordance with the concentration of free chlorine residual, the cell being essentially insensitive to combined chlorine residual.

Electrochemical chlorine flux monitor

Abstract: This apparatus for monitoring the chlorine concentration of water has a uue internal calibration capability and a high sensitivity. A water sample is mixed with a solution of potassium iodide and the reaction produces a mole of iodine for every mole of chlorine present in the water. The mixture is passed through a detection and calibration assembly wherein the iodine is detected amperometrically by a detection cell. Calibrant (known) iodine fluxes, equivalent in effect to the unknown chlorine-produced iodine fluxes, are supplied to the detection cell during calibration runs by means of an upstream calibration cell which electrolyzes the iodide (preferably added to distilled water) to iodine at flux rates given simply by the electrolyzing currents divided by Faraday's constant. An electronics package having gain and offset controls and a concentration display is provided.

The sum of chlorinated and of brominated non-polar hydrocarbons in water

Abstract: It is proposed to use chlorine as a common parameter in the study of the non-polar chlorinated hydrocarbons in the aquatic environment. Also the ratio of the sum of chlorine to bromine may be useful indicator of pollution by such compounds. Detector of chlorine and of bromine in this form is based on neutron activation analysis. Further information on the nature of organochlorine material is obtained by studying variations in the chlorine content with chemical and physical manipulations. Simultaneous determination of known organochlorine micropollutants allows the level of unidentified chlorinated hydrocarbons to be assessed. In samples of fresh- and sea-water so far analyzed, the total content of non-polar organic bound chlorine exceeds that which can be accounted for as polychlorinated biphenyls (PCB) by a factor of 10 to 100.

Process for selectively chlorinating the titanium content of titaniferous materials

Abstract: A reduction/chlorination process is provided for the treatment of titaniferous materials such as ilmenite ores. The chlorination is selective in that the titanium constituent of the titaniferous material is chlorinated, but there is no appreciable net yield of iron chloride from the iron constituent. Where other metals such as vanadium are present they may be chlorinated with the titanium. The reduction utilizes as the reductant an amount of carbonaceous material which, based on oxygen in the titaniferous material, is at least stoichiometric to produce carbon monoxide. The selective chlorination utilizes as the chlorinating agent either ferrous chloride (FeCl 2 ) alone or certain combinations of ferrous chloride and one or more other chloride-containing members, notably molecular chlorine (Cl 2 ) and hydrogen chloride (HCl). The use of ferric chloride (FeCl 3 ) as a part or all of the chlorinating agent is the equivalent of using a FeCl 2 /0.5 Cl 2 mixture. Preferably, sufficient chlorine atoms are provided by the chlorinating agent to react with essentially all of the titanium in the titaniferous material. An elevated temperature in the range of 950° to 1400°C. is maintained during the chlorination, but depending upon the composition of the chlorinating agent, there may be a minimum temperature in the range which is needed to maintain selectivity.