Magnesium chloride oxide

The polymerization is carried out at temperatures of 0—80°C in 1—5 h at a soHds concentration of 6—12%. The polymerization is terminated by neutralizing agents such as calcium hydroxide, calcium oxide, calcium carbonate, or lithium hydroxide. Inherent viscosities of 2-4 dL/g are obtained at 3,4 -dianiinodiphenyl ether contents of 35—50 mol %. Because of the introduction of nonlinearity into the PPT chain by the inclusion of 3,4 -dianiinodiphenyl ether kinks, the copolymer shows improved tractabiUty and may be wet or dry jet-wet spun from the polymerization solvent. The fibers are best coagulated in an aqueous equiUbrium bath containing less than 50 vol % of polymerization solvent and from 35 to 50% of calcium chloride or magnesium chloride. 

Molten magnesium chloride can be formed by the direct carbochlofination of magnesium oxide obtained from the calciaation of magnesium carbonate ores or magnesium hydroxide [1309-42-8]. 

Preparation and Manufacture. Magnesium chloride can be produced in large quantities from (/) camalhte or the end brines of the potash industry (see Potassium compounds) (2) magnesium hydroxide precipitated from seawater (7) by chlorination of magnesium oxide from various sources in the presence of carbon or carbonaceous materials and (4) as a by-product in the manufacture of titanium (see Titaniumand titanium alloys). 

When magnesium oxide is chlorinated in the presence of powdered coke or coal (qv), anhydrous magnesium chloride is formed. In the production of magnesium metal, briquettes containing CaCl2, KCl, NaCl, MgO, and carbon are chlorinated at a temperature such that the electrolyte or cell melt collects at the bottom of the chlorinator, enabling the Hquid to be transferred directly to the electrolytic cells. 

Dead Seas Periclase Ltd., on the Dead Sea in Israel, uses yet another process to produce magnesium oxide. A concentrated magnesium chloride brine processed from the Dead Sea is sprayed into a reactor at about 1700°C (127,128). The brine is thermally decomposed into magnesium oxide and hydrochloric acid. To further process the magnesia, the product is slaked to form magnesium hydroxide which is then washed, filtered, and calcined under controlled conditions to produce a variety of MgO reactivity grades. A summary of MgO purities, for the various processes is given in Table 20. 

Present Day Methods, In the Grignard Sjnthesis (82,83), chlorobenzene [108-90-7] is converted to phenyhnagnesium chloride which reacts with ethylene oxide [75-21-8] at 100°C to give P-phenylethoxy magnesium chloride which is then decomposed with sulfuric acid to give PEA. 

DihydroxyanthraquiQone (anthranifin) [117-12-4] (47) is an important iatermediate for manufacturiag disperse blue dyes, eg. Cl Disperse Blue 73 (113), and is prepared from anthraquiQone-l,5-disulfonic acid by heating with an aqueous suspension of calcium oxide and magnesium chloride under pressure at 200—250°C (67). Alternative methods have been proposed, ie, direct replacement of the NO2 groups of 1,5-dinitroanthraquiaone (49) (68) or the route via 1,5-dimethoxyanthraquiaone [6448-90-4] (48) and subsequent hydrolysis (69). 

Butyroin has been prepared by reductive condensation of ethyl butyrate with sodium in xylene, or with sodium in the presence of chloro-trimethylsilane. and by reduction of 4,5-octanedlone with sodium l-benzyl-3-carbamoyl-l,4-dihydropyridine-4-sulfinate in the presence of magnesium chloride or with thiophenol in the presence of iron polyphthalocyanine as electron transfer agent.This acyloin has also been obtained by oxidation of (E)-4-octene with potassium permanganate and by reaction of... 

Liquid hydrogen chloride does not conduct electricity and is without action on zinc, iron, magnesium, calcium oxide and certain carbonates. However, it does dissolve aluminium. 

Use the formulas for magnesium oxide, MgO, and magnesium chloride, MgCl2, together with the periodic table to decide that magnesium ions have the same number of electrons as each of the following, EXCEPT... 

FIGURE 12.12 A schematic representation of the electrolytic cell used in the Dow process for magnesium. The electrolyte is molten magnesium chloride. As the current generated by the external source passes through the cell, magnesium ions are reduced to magnesium metal at the cathode and chloride ions are oxidized to chlorine gas at the anode. 

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. 

The three major types of oxysalt bonded AB cement are the zinc oxychloride, the magnesium chloride and the magnesium oxysulphate cements. The bases employed, therefore, are either zinc oxide or magnesium oxide, both of which readily undergo hydration in aqueous solution, behaving as M(OH)2 species and acting as a source of hydroxyl ions. They are thus both clearly bases in the Bronsted-Lowry sense. 

Bury, C. R. Davies, E. R. H. (1932). System magnesium oxide-magnesium chloride-water. Journal of the Chemical Society, 2008-15. 

At many plants, fluxes are added to the metal to reduce hydrogen contamination, remove oxides, and eliminate undesirable trace elements. Solid fluxes such as hexachloroethane, aluminum chloride, and anhydrous magnesium chloride may be used, but it is more common to bubble gases such as chlorine, nitrogen, argon, helium, and mixtures of chlorine and inert gases through the molten metal. 

Refluxing with sodium helps to remove the small amount of benzyl alcohol formed by the atmospheric oxidation of benzyl-magnesium chloride. 

The diol function of 130 was protected as its acetonide 131 (88 %). Next, the enone function was installed by a-selenation of the enoxysilane, followed by peroxide oxidation and elimination (57 % over two steps). Finally, the unsaturated ketone 132 was homologated by 1,4-addition of trimethylsilylmethyl magnesium chloride, trapping with chlorotrimethylsilane, and reoxidation, to afford the target 117 (88 %). 

---