Magnesium and alkaline earth metals

Table 12.2. Magnesium and alkaline earth metal alkoxides... 

Magnesium and alkaline-earth metals (European Pharmacopoeia 2.4.7)... 

If the sample solution contains any ions of magnesium and alkaline-earth metals, they will replace zinc and form EDTA complexes since their apparent stability constants are much larger than zinc. The zinc set free will form a complex with the indicator changing the color to violet. The amount of zinc replaced is equivalent to the amoimt of magnesium, and alkaline-earth metals in the sample solution is determined in the second titration. 

Reactions of Magnesium and Alkaline Earth Metals with Alcohols in the Presence of Other Metal (Al, Zr, Nb, etc.) Alkoxides (B)... 

Reduction to Gaseous Metal. Volatile metals can be reduced and easily and completely separated from the residue before being condensed to a hquid or a soHd product in a container physically separated from the reduction reactor. Reduction to gaseous metal is possible for 2inc, mercury, cadmium, and the alkah and aLkaline-earth metals, but industrial practice is significant only for 2inc, mercury, magnesium, and calcium. 

Dry methyl chloride is unteactive with all common metals except the alkaU and alkaline-earth metals, magnesium, 2iac, and alumiaum. In dry ether solution, methyl chloride reacts with sodium to yield ethane by the Wurt2 synthesis ... 

Alkali and alkaline earth metals, e.g. sodium, potassium lithium, magnesium, calcium, powdered aluminium Anhydrous ammonia Ammonium nitrate... 

Acetone Acetylene Alkali and alkaline earth metals, e.g. sodium, potassium, lithium, magnesium, calcium, powdered aluminium Anhydrous ammonia Concentrated nitric and sulphuric acid mixtures Chlorine, bromine, copper, silver, flourine or mercury Carbon dioxide, carbon tetrachloride, or other chlorinated hydrocarbons. (Also prohibit, water, foam and dry chemical on fires involving these metals - dry sand should be available.) Mercury, chlorine, calcium hypochlorite, iodine, bromine or hydrogen fluoride... 

Several recent determinations of the alkali and alkaline earth metals in serum or urine have been reported. Barrett 29) determined potassium, sodium, and calcium in semm by diluting the samples with lanthanum chloride solution. Suttle and Field 3°) used atomic absorption spectroscopy to determine potassium and magnesium in sheep plasma. 

The alkali and alkaline earth metals are examples of relatively simple cations that occur in only one oxidation state and are surrounded by water (see Figure 6.1). The most common of these ions in soil, in order of decreasing abundance, are calcium (Ca2+), magnesium (Mg2+), potassium (K+), and sodium (Na+). Sodium is typically present in very small amounts in high-rainfall areas, whereas it may have a relatively high concentration in low-rainfall areas. 

Biodiesel is a mixture of methyl esters of fatty acids and is produced from vegetable oils by transesterification with methanol (Fig. 10.1). For every three moles of methyl esters one mole of glycerol is produced as a by-product, which is roughly 10 wt.% of the total product. Transesterification is usually catalyzed with base catalysts but there are also processes with acid catalysts. The base catalysts are the hydroxides and alkoxides of alkaline and alkaline earth metals. The acid catalysts are hydrochloride, sulfuric or sulfonic acid. Some metal-based catalysts can also be exploited, such as titanium alcoholates or oxides of tin, magnesium and zinc. All these catalyst acts as homogeneous catalysts and need to be removed from the product [16, 17]. The advantages of biodiesel as fuel are transportability, heat content (80% of diesel fuel), ready availability and renewability. The... 

Intimate mixtures of chlorates, bromates or iodates of barium, cadmium, calcium, magnesium, potassium, sodium or zinc, with finely divided aluminium, arsenic, copper carbon, phosphorus, sulfur hydrides of alkali- and alkaline earth-metals sulfides of antimony, arsenic, copper or tin metal cyanides, thiocyanates or impure manganese dioxide may react violently or explosively, either spontaneously (especially in presence of moisture) or on initiation by heat, friction, impact, sparks or addition of sulfuric acid [1], Mixtures of sodium or potassium chlorate with sulfur or phosphorus are rated as being exceptionally dangerous on frictional initiation. 

Sodium, potassium, magnesium and other alkah and alkaline earth metals at elevated temperatures reduce horon trichloride to elemental horon ... 

Magnesium carbonate forms several double salts with salts of alkali and alkaline earth metals and ammonium ion. Some examples are ... 

FIGURE 14.3 Isocratic separation of morpholine, alkali, and alkaline earth metals on lonPac CS12A column. Eluent lOmM sulfuric acid. Detection suppressed conductivity. Peaks 1, lithium (0.5mg/L) 2, sodium (2mg/L) 3, ammonium (2.5mg/L) 4, potassium (5mg/L) 5, morpholine (25mg/L) 6, magnesium (2.5mg/L) 7, calcium (5mg/L). (From Rey, M.A. and Pohl, C.A., J. Chromatogr. A, 739, 87, 1996. Copyright 1996. With permission from Elsevier.)... 

Schmidbaur, H., Classen, H. G., and Helbig, J. (1990). Aspartic and glutamic acid as ligands to alkali and alkaline-earth metals Structural chemistry as related to magnesium therapy. Angew. Chem., Int. Ed. Engl. 29, 1090-1103. 

The alkali and alkaline earth metals - such as sodium, potassium, barium, and calcium — would make excellent high-energy fuels, but, except for magnesium, they are too reactive with moisture and atmospheric oxygen. Sodium metal, for example, reacts violently with water and must be stored in an inert organic liquid, such as xylene, to minimize decomposition. 

Tanaka et al. reported that gasoline POX over Rh, Pt, and Pt-Rh is promoted by alkali (Li) and alkaline earth metals (Ba, Ca, K) supported on magnesium aluminate spinel. The catalysts were tested isothermally at 800°C at an air to fuel ratio of 5.1 and GHSV 50,000 h Li, Mg and MgLi promoters were added to Pt supported on MgAl204 spinel. All catalysts produced similar H2 and CO reformate concentrations of 23 and 25 vol%, respectively. There was a discernable difference in the carbon deposition. The unpromoted Pt catalyst showed carbon levels of 0.02 wt% carbon, where the alkali and alkaline earth promoted Pt catalysts had carbon levels of 0.01 wt%. 

By careful choice of the storage material, catalysts with differing storage capacities and thermal properties can be designed for applications with different temperature ranges. Typical adsorber materials are the alkali and alkaline-earth metal oxides, e.g. barium, magnesium, potassium and cesium. 

The salts of the alkali and alkaline earth metals, as well as of gold, magnesium, beryllium and yttrium, are soluble in water, the solutions being colourless or pale yellow. They gradually decompose, however, when kept, with deposition of sulphur, arsenic and arsenic pentasulphide. The following thioarsenates have been described. 

Application of Job s principle00 to aqueous solutions of sucrose and alkaline-earth metal salts (magnesium sulfate, calcium acetate, and barium chloride), whose combined concentration was 1 M, gave curves of Aa against concentration that exhibited two maxima, one at 0.5 M sucrose and the other at 0.66 M sucrose. These observations suggest that both 1 1 and 2 1 carbohydrate-salt adducts can exist in solution. 

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