Water with alkali metals

Hunger B., Klepel O., Kirschhock C., Heuchel M., Toufar H. and Fuess H., Interaction of water with alkali-metal cation-exchanged X type zeolites TPD and XRD study. Langmur, 15 (1999) pp. 5937-5941... 

Such water, and also that containing salts of multipositive metals, (usually sulphates), is said to be hard since it does not readily produce a lather with soap. Experiments with alkali metal salts can be performed to verify that the hardness is due to the presence of the multipositive metal ions and not to any of the anions present. The hardness due to calcium and magnesium hydrogencarbonates is said to be temporary since it can be removed by boiling ... 

Hot corrosion is a rapid form of attack that is generally associated with alkali metal contaminants, such as sodium and potassium, reacting with sulfur in the fuel to form molten sulfates. The presence of only a few parts per million (ppm) of such contaminants in the fuel, or equivalent in the air, is sufficient to cause this corrosion. Sodium can be introduced in a number of ways, such as salt water in liquid fuel, through the turbine air inlet at sites near salt water or other contaminated areas, or as contaminants in water/steam injections. Besides the alkali metals such as sodium and potassium, other chemical elements can influence or cause corrosion on bucketing. Notable in this connection are vanadium, primarily found in crude and residual oils. 

Specific gravity is the weight of the fuel in relation to water. This property is important in the design of centrifugal fuel washing systems. Sulfur content is important in connection with emission concerns and in connection with the alkali metals present in the ash. Sulfur reacting with alkali metals forms compounds that corrode by a process labeled sulfidation. 

Hydrides — True hydrides (i.e., those in which the hydrogen is in its anionic or most reduced form) are salt-like compounds in which the hydrogen is combined with alkali metals, either alone as simple hydrides or in association with other elements as complex hydrides. Hydrides react with water to release hydrogen. 

Chemical Reactivity - Reactivity with Water No reaction Reactivity with Common Materials May attack some forms of plastics Stability During Transport Stable Neutralizing Agents for Acids and Caustics Not pertinent,- Polymerization Hazardous polymerization unlikely to occur except when in contact with alkali metals or metallo-organic compounds Inhibitor of Polymerization 10 -20 ppm tert-butylcatechol. 

Figure 4.11 Molecular structures of typical crown-ether complexes with alkali metal cations (a) sodium-water-benzo-I5-crown-5 showing pentagonal-pyramidal coordination of Na by 6 oxygen atoms (b) 18-crown-6-potassium-ethyl acetoacetate enolate showing unsymmelrical coordination of K by 8 oxygen atoms and (c) the RbNCS ion pair coordinated by dibenzo-I8-crown-6 to give seven-fold coordination about Rb.

Alternatively, esterification of carboxylic acid can be carried out in aqueous media by reacting carboxylic acid salts with alkyl halides through nucleophilic substitutions (Eq. 9.10).20 The reaction rate of alkyl halides with alkali metal salts of carboxylic acids to give esters increases with the increasing concentration of catalyst, halide, and solvent polarity and is reduced by water. Various thymyl ethers and esters can be synthesized by the reactions of thymol with alkyl halides and acid chlorides, respectively, in aqueous medium under microwave irradiation (Eq. 9.11).21 Such an esterification reaction of poly(methacrylic acid) can be performed readily with alkyl halides using DBU in aqueous solutions, although the rate of the reaction decreases with increasing water content.22... 

Simple transition metal halides react cleanly with alkali metal boratabenzenes. In this way sandwich-type complexes 32 of V (27), Cr (64), Fe (58), Ru (61), and Os (61) have been made. The corresponding nickel complexes seem to be nonexistent, quite in contrast to NiCp2 in attempted preparations, mixtures of diamagnetic C—C linked dimers were obtained (29). In the manganese case, high sensitivity to air and water has precluded preparative success until now. Some organometallic halides have added further variations to the main theme. The complexes 33 of Rh and 34 of Pt were obtained from [(COD)RhCl]2 and [Me3PtI]4, respectively (61). 

The alkali metal cyanides are very soluble in water. As a result, they readily dissociate into their respective anions and cations when released into water. Depending on the pH of the water, the resulting cyanide ion may then form hydrogen cyanide or react with various metals in natural water. The proportion of hydrogen cyanide formed from soluble cyanides increases as the water pH decreases. At pH <7, >99% of the cyanide ions in water is converted to hydrogen cyanide (Towill et al. 1978). As the pH increases, cyanide ions in the water may form complex metallocyanides in the presence of excess cyanides however, if metals are prevalent, simple metal cyanides are formed. Unlike water-soluble alkali metal cyanides, insoluble metal cyanides such as are not expected to degrade to hydrogen cyanide (Callahan et al. 1979). 

Cyclooctatetraene was reduced electrochemically to cyclooctatetraenyl dianion. In DMF the product is mostly (92%) 1,3,5-cyclooctatriene at —1.2 V. If the potential is lowered the main product is 1,3,6-cyclooctatriene. Previous experiments, in which the anion radical was found to be disproportionated, were explained on the basis of reactions of the cyclooctatetraene dianion with alkali metal ions to form tightly bound complexes, or with water to form cyclooctatrienes. The first electron transfer to cyclooctatetraene is slow and proceeds via a transition state which resembles planar cyclooctatetraene102. 

Yeager and Steck derived diffusion coefficients for water in totally hydrated Nafion 120 membranes that were exchanged with alkali metal cations, using a radiotracer technique. At 25 °C, 77for the Na+ form was 2.65 X 10 cm /s and the values for the K+ and Cs+ forms were somewhat smaller, which would seem to reflect the lower maximal degree of hydration of these forms. 

Chemical/Physical. Carbon dioxide, chloride, dichloromaleic, oxalic and glycolic acids, were reported as ozonation products of 2,4,5-T in water at pH 8 (Struif et al., 1978). Reacts with alkali metals and amines forming water-soluble salts (Worthing and Hance, 1991). When 2,4,5-T was heated at 900 °C, carbon monoxide, carbon dioxide, chlorine, HCl, and ojtygen were produced (Kennedy et al, 1972, 1972a). 

Synthetic routes to a-nitroalkenes have been discussed in previous sections. General routes include (1) treating /3-nitroacetates with alkali metal acetates, carbonates or bicarbonates, (2) elimination of water from /3-nitroalcohols via heating with phthalic anhydride or in the presence of a base," ° and (3) degradation of the Mannich products derived from a primary nitroalkane, formaldehyde, and a secondary amine. ... 

Prospects for TR Electrolyte SBs. In view of the harmful effects often cited in the literature of even small traces of water on the operation of non-aqueous batteries with alkali metal anodes, it might be supposed that electrolytes of the TR composition cannot be applied in such batteries. This same idea may dominate when molten salt SBs are considered. Such a general conclusion cannot be justified. A dilute solution of water in a salt has the structure either of this salt proper or its adjacent hydrate, and the energy, properties and reactions of this water are quite different from those of pure water or of dilute solutions of various compounds in it. On the other hand, a small amount of water in the electrolyte system will decrease its melting point and increase its conductivity. Mixtures of water with such liquids as some alcohols or dioxane and other aprotic and even proton-forming substances, may open new prospects for... 

Mercury(ll) sulfate hydrolyzes in water forming a basic sulfate HgS04 2Hg0. It forms double sulfates with alkali metal sulfates, such as K2S04-3HgS04-2H20. 

Binary Selenides. Most binary selenides are formed by heating selenium in the presence of the element, reduction of selenites or selenates with carbon or hydrogen, and double decomposition of heavy-metal salts in aqueous solution or suspension with a soluble selenide salt, eg, Na2Se or (NH Se [66455-76-3]. Atmospheric oxygen oxidizes the selenides more rapidly than the corresponding sulfides and more slowly than the tellurides. Selenides of the alkali, alkaline-earth metals, and lanthanum elements are water soluble and readily hydrolyzed. Heavy-metal selenides are insoluble in water. Polyselenides form when selenium reacts with alkali metals dissolved in liquid ammonia. Metal (M) hydrogen selenides of the M HSe type are known. Some heavy-metal selenides show important and useful electric, photoelectric, photo-optical, and semiconductor properties. Ferroselenium and nickel selenide are made by sintering a mixture of selenium and metal powder. 

Tellurates. The water-soluble alkali metal and alkaline-earth tellurates are prepared by chlorinating alkaline solutions of the tellurites or by heating solid tellurites with KN03, KQ03, or Pb02 to form, for example, potassium tellurate [7790-58-1], Iv-TeO,. The insoluble tellurates are made by... 

AN with sufficient water to give such viscosity that the particulate material remains in suspension and hence in uniform distribution thruout the slurry. The viscosity may be improved by adding thickeners such as guar gum, polyacrylamides, etc, with or without cross-linking agents. Up to 50% NC may be replaced with TNT, Tetryl, PETN, RDX or HMX up to 25% AN may be replaced with alkali metal nitrates, such as NaNOg)... 

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