Metals magnesium salts

Magnesium salts 12 are the most important among the dithiocarboxylate salts of alkaline earth metals. Magnesium salts 12 are prepared by insertion of CS2 using Grignard reagents (Scheme 4) [41]. These salts 12 are treated with acid, alkyl halides and alkyl triflates to prepare dithiocarboxylic acids and esters, respectively [42-45]. A dinuclear aluminum-magnesium compound 13 is also synthesized by insertion of CS2 into the Mg-C bond (Fig. 4) [46]. 

Detergents are metal salts of organic acids used primarily in crankcase lubricants. Alkylbenzenesulfonic acids, alkylphenols, sulfur- and methjiene-coupled alkyl phenols, carboxyUc acids, and alkylphosphonic acids are commonly used as their calcium, sodium, and magnesium salts. Calcium sulfonates, overbased with excess calcium hydroxide or calcium carbonate to neutralize acidic combustion and oxidation products, constitute 65% of the total detergent market. These are followed by calcium phenates at 31% (22). 

In seawater—dolime and hrine—dolime processes, calcined dolomite or dolime, CaO MgO, is used as a raw material (Table 9). Dolime typically contains 58% CaO, 41% MgO, and less than 1% combined Si02, P O, and CO2 where R is a trivalent metal ion, eg, Al " or Fe " ( 4). Roughly one-half of the magnesia is provided by the magnesium salts in the seawater or brine and the other half is from dolime (75). Plant size is thus reduced using dolime and production cost is probably lower. 

Fast Color Salts. In order to simplify the work of the dyer, diazonium salts, in the form of stable dry powders, were introduced under the name of fast color salts. When dissolved in water they react like ordinary diazo compounds. These diazonium salts, derived from amines, free from solubilizing groups, are prepared by the usual method and are salted out from the solutions as the sulfates, the metallic double salts, or the aromatic sulfonates. The isolated diazonium salt is sold in admixture with anhydrous salts such as sodium sulfate or magnesium sulfate. 

Chemical inhibitors, when added in small amounts, reduce corrosion by affecting cathodic and/or anodic processes. A wide variety of treatments may be used, including soluble hydroxides, chromates, phosphates, silicates, carbonates, zinc salts, molybdates, nitrates, and magnesium salts. The exact amount of inhibitor to be used, once again, depends on system parameters such as temperature, flow, water chemistry, and metal composition. For these reasons, experts in water treatment acknowledge that treatment should be fine tuned for a given system. 

Conditions within a few hundred metres of the surf line on beaches are intermediate between total immersion in sea-water and normal exposure to a marine atmosphere. High corrosion rates can occur on some tropical surf beaches where the metal remains wet and where inhibiting magnesium salts are not present in the sea-water. 

The diazonio group in an arenediazonium salt can be replaced by one of several transition metal ions in subgroups lb (Cu), Illb (Tl), IVb (Ge, Sn, Pb), or Vb (P, As, Sb, Bi) or by certain compounds of the transition elements. There is only one report of a substitution by a main group metal, magnesium, but the primary product has not been clearly identified (Nesmeyanov and Makarova, 1959). 

Metallic magnesium is produced by either chemical or electrolytic reduction of its compounds. In chemical reduction, first magnesium oxide is obtained from the decomposition of dolomite. Then ferrosilicon, an alloy of iron and silicon, is used to reduce the MgO at about 1200°C. At this temperature, the magnesium produced is immediately vaporized and carried away. The electrolytic method uses seawater as its principal raw material magnesium hydroxide is precipitated by adding slaked lime (Ca(OH)2, see Section 14.10), the precipitate is filtered off and treated with hydrochloric acid to produce magnesium chloride, and the dried molten salt is electrolyzed. 

There was a surprising fatal accident during which an iron container with magnesium chloride (probably moist) detonated. It was thought that the magnesium salt had catalysed the interaction between the metal and water. 

Several octahedral dihydrazine metal (II) salts of this class were prepared and thermally decomposed. The succinates and malonates of nickel and cadmium decomposed explosively [1]. A later paper on mixed metal bis-hydrazine malonates of cobalt with magnesium, manganese, nickel, zinc or cadmium recommends that decomposition, in a pre-heated crucible at 500°C, be of small quantities only. The same workers have reported exothermic decomposition of similar hydrazine complexed salts of other small organic acids. 

Desimoni and coworkers84 probed the catalytic effect of metal perchlorate salts on the rate of the Diels-Alder reactions between malonates 88 and cyclopentadiene (equation 27). They found that especially magnesium perchlorate was able to catalyze the reaction by binding two malonates in a bidentate fashion. Reaction times were shortened up to 1000 times. The endo/exo selectivity was inverted from 89/90 = 40/60 (n =4) and 17/83 (n = 5) for the thermal uncatalyzed reactions to 89/90 = 60/40 (n = 4) and 80/20 (n = 5) for the magnesium perchlorate catalyzed reactions. 

Alkali metal reductions of metallic salts using an arene as electron carrier, lithium being the most used metallic component (Rieke method) . Although not belonging to this group of metals, magnesium-anthracene has found some apphcations in the activation of other metals . 

Although beryllium and magnesium salts do not form stable mctal-ammines yet they unite with ammonia, forming additive compounds of the hydrate type which are sometimes referred to as ammoniates or ammonio-compounds. These appear to be of the same type as the metal-anunines, and the difference seems to be merely one of stability. The ammonio-compounds are formed by the addition of ammonia gas to dry or fused salt, and most of them decompose with liberation of ammonia when dissolved in water. 

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