Chlorine with magnesium

The extraction of titanium is still relatively costly first the dioxide Ti02 is converted to the tetrachloride TiCl4 by heating with carbon in a stream of chlorine the tetrachloride is a volatile liquid which can be rendered pure by fractional distillation. The next stage is costly the reduction of the tetrachloride to the metal, with magnesium. must be carried out in a molybdenum-coated iron crucible in an atmospheric of argon at about 1100 K ... 

Fig. 4. Flow sheet for the processing of titanium ore by chlorination followed by reduction with magnesium.

The reaction is carried out by first reacting the alkyl or aryl halide with magnesium shavings in an ether suspension and then treating with silicon tetrachloride (prepared by passing chlorine over heated silicon). With methyl chloride the following sequence of reactions occur ... 

The reaction of magnesium, with two valence electrons, and chlorine, with seven valence electrons will produce magnesium chloride. The magnesium must donate one valence electron to each of two chlorine atoms. This leaves a magnesium ion and two chloride ions. All the ions have a complete octet. The ions form the ionic compound magnesium chloride, MgCl2. 

A comprehensive review covers stability relationships and reactions of these explosive compounds and their derivatives. Bromine, chlorine and iodine azides all explode violently in contact with magnesium, zinc or white phosphorus. 

Zirconium metal is produced from its tetrachloride by reduction with magnesium by the Kroll process. The oxide obtained above is converted to zirconium tetrachloride by heating with carbon and chlorine. In practice, the oxide is mixed with lampblack, powdered sugar, and a little water, and pelletized. The dried pellet is then heated with chlorine in a chlorinator to produce ziro-conium tetrachloride ... 

Shimizu attributes much of the value of these chlorine donors in magnesium-containing compositions to the production in the flame of hydrogen chloride, which reacts with magnesium oxide to form volatile MgCl molecules. The incandescent emission from... 

Place the prepared silicon (or the product of reacting silicon(lV) oxide with magnesium) in a porcelain boat into quartz tube 1 of the apparatus shown in Fig. 111. Dry the apparatus and the silicon in a stream of dry carbon dioxide at 200 °C during one hour. Raise the temperature of the furnace to 400 C and use a chlorine stream instead of that of carbon dioxide. Perform chlorination during... 

Free-base porphyrins can be chlorinated with hydrogen peroxide-hydrochloric acid mixtures, but formation of mono- and di-substituted derivatives is not easy to control, the reaction preferring to produce the methine tetrachloro derivative. The magnesium(II) comptex of porphin (1) can be transformed into the 5,10,15,20-tetrabromo derivative with NBS, and no peripheral substitution is observed however, free-base porphin (1) is mono-brominated at a peripheral carbon under these circumstances. Treatment of deuteropor-phyrin-IX (Table 1) with pyridinium bromide perbromide gives the 3,8-dibromo derivative. 

Chlorine occurs in coal (Chakrabarti, 1978, 1982 Hower et al 1992) and is believed to be a factor not only in fouling problems but also in corrosion problems (Canfield et al., 1979 Slack, 1981). The chlorine content of coal is normally low, usually only a few tenths of a percent or less. It occurs predominantly as sodium, potassium, and calcium chlorides, with magnesium and iron chlorides present in some coals. There is evidence that chlorine may also be combined with the organic matter in coal. 

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