Titanium tetrachloride reduction

Both the Toth and Alcoa processes provide aluminum chloride for subsequent reduction to aluminum. Pilot-plant tests of these processes have shown difficulties exist in producing aluminum chloride of the purity needed. In the Toth process for the production of aluminum chloride, kaolin [1332-58-7] clay is used as the source of alumina (5). The clay is mixed with sulfur and carbon, and the mixture is ground together, pelletized, and calcined at 700°C. The calcined mixture is chlorinated at 800°C and gaseous aluminum chloride is evolved. The clay used contains considerable amounts of silica, titania, and iron oxides, which chlorinate and must be separated. Silicon tetrachloride and titanium tetrachloride are separated by distillation. Resublimation of aluminum chloride is requited to reduce contamination from iron chloride. 

The 1990s reduction process was based on work started in the early 1930s. A magnesium vacuum reduction process was developed for reduction of titanium tetrachloride to metal. Based on this process, the U.S. Bureau of Mines (BOM) initiated a program in 1940 to develop commercial production. Some years later, the BOM pubHcized its work on titanium and made samples available to the industrial community. By 1948, the BOM produced batch sizes of 104 kg. In the same year, Du Pont aimounced commercial availabiHty of titanium, thus beginning the modem titanium metals industry (1). 

Tetrachloride-Reduction Process. Titanium tetrachloride for metal production must be of very high purity. The requited purity of technical-grade TiCl for pigment production is compared with that for metal production in Table 4. Titanium tetrachloride for metal production is prepared by the same process as described above, except that a greater effort is made to remove impurities, especially oxygen- and carbon-containing compounds. 

Titanium trichloride is almost always prepared by the reduction of TiCl, most commonly by hydrogen. Other reduciag agents iaclude titanium, aluminum, and 2iac. Reduction begias at temperatures of ca 500°C and under these conditions a-TiCl is formed. The product is cooled quickly to below 450°C to avoid disproportionation to the di- and tetrachlorides. P-TiCl is prepared by the reduction of titanium tetrachloride with aluminum alkyls at low (80°C) temperatures whereas y-TiCl is formed if titanium tetrachloride reacts with aluminum alkyls at 150—200°C. At ca 250°C, the P-form converts to d. d-TiCl is made by prolonged grinding of the d- or y-forms. 

Titanium diiodide may be prepared by direct combination of the elements, the reaction mixture being heated to 440°C to remove the tri- and tetraiodides (145). It can also be made by either reaction of soHd potassium iodide with titanium tetrachloride or reduction of Til with silver or mercury. 

This was converted to its imine with methylamine catalyzed by titanium tetrachloride and then sodium borohydride reduction produced 17 as a mixture of diastereomers. This was resolved by column chromatography to give sertraline [5]. Dextrorotatory cis sertraline is substantially more potent than its isomers. 

The ease of oxidation of magnesium is important in the commercial manufacture of titanium metal. Titanium, when quite pure, shows great promise as a structural metal, but the economics of production have thus far inhibited its use. One of the processes currently used, the Kroll process, involves the reduction of liquid titanium tetrachloride with molten metallic magnesium ... 

Reduction Reactions. Titanium nitride coatings are produced by CVD with titanium tetrachloride as the metal source and either nitrogen gas or ammonia as a source of nitrogen ... 

C20-0061. Write balanced chemical equations for the following metallurgical processes (a) roasting of CuFeS2 (b) removal of silicon from steel in a converter and (c) reduction of titanium tetrachloride using sodium metal. 

The formation of carbon monoxide aids chlorination in exactly the same way as does the formation of carbon dioxide which of the two oxides of carbon would found in the reaction depends on the temperature at which reduction-chlorination is carried out. Below 600 °C carbon dioxide forms while above 700 °C carbon monoxide is formed. This changeover results from the variation in the free energies of formation of these two oxides with temperature. For example, at 900 °C the situation as regards the formation of titanium tetrachloride from titanium dioxide is guided by the reactions ... 

Titanium tetrachloride is produced on an industrial scale by the chlorination of titanium dioxide-carbon mixtures in reactors lined with silica. During the reactor operation, the lining comes into contact not only with chlorine but also with titanium tetrachloride. There appears to be no attack on silica by either of these as the lining remains intact. However, the use of such a reactor for chlorinating beryllium oxide by the carbon-chlorine reduction chlorination procedure is not possible because the silica lining is attacked in this case. This corrosion of silica can be traced to the attack of beryllium chloride on silica. The interaction of beryllium chloride with silica results in the formation of silicon tetrachloride in accordance with the reaction... 

Another chloride reduction process, originally developed by Hunter for titanium tetrachloride and known by his name, uses sodium as the reductant. In this process liquid sodium and titanium tetrachloride are simultaneously metered into a steel retort under an argon atmosphere. The highly exothermic reduction reaction... 

C by external cooling. During this process a part of the reduction occurs between titanium tetrachloride and sodium vapor and this leads to the formation of titanium powder. To avoid this, the reduction is carried out in two steps. Initially, stoichiometric amounts of sodium and titanium tetrachloride are metered into the steel retort at 700 to 750 °C to produce titanium dichloride ... 

NAPHTHALENE THIOL, 51, 139 Titanium tetrachloride, 54, 93 o-Tolualdehyde, by reduction of... 

Another useful route to alkaloids involves the electrochemical oxidation of lactams (145) bearing functionality on nitrogen that can be used to intramolec-ularly capture an intermediate acyl im-minium ion (146). The concept is portrayed in Scheme 33 and is highlighted by the synthesis of alkaloids lupinine (150) and epilupinine (151) shown in Scheme 34 [60]. Thus, the electrooxidation of lactam (147) provided a 71% yield of ether (148). Subsequent treatment with titanium tetrachloride affected cyclization and afforded the [4.4.0] bicyclic adduct (149). Krapcho decarbomethoxylation followed by hydride reduction of both the... 

The amount of amorphous polymer, which is generally produced in small percentage (9-16%) contemporaneously with the non-atactic polymer, is independent of reaction time (see Table II). It is on the contrary closely connected with the nature of the catalytic system employed and changes, for instance, when the triethylaluminum is substituted by other metal alkyls (beryllium alkyls, propylaluminum, isobutylaluminum, etc.) 5,28). It also depends on the purity of the a-titanium trichloride, in particular increasing in the presence of other crystalline modifications of titanium trichloride [i.e. -TiCU (27)] and of titanium compounds obtained by reduction of titanium tetrachloride at low temperature with aluminum alkyls. 

Figure 17.13 shows immediately that carbon is useless as a reductant for chlorides, since CCU is barely thermodynamically stable even at room temperature and becomes endergonic above about 400 °C. Similarly, CF4 is the least exergonically formed (per F atom) of all the fluorides covered by Fig. 17.13, and so carbon cannot reduce them. In principle, hydrogen could reduce titanium tetrachloride to titanium, but in reality titanium hydrides (Section 5.7) would be obtained. The only satisfactory reductants for metal chlorides and fluorides are magnesium and (less practically, on account of their extreme reactivity) sodium or calcium. 

The Schmidt reaction affords both possible isomers when applied at the sulfide oxidation level, and also with the sulfoxide, no trace of sulfoximine being found (75CJC276). Reduction of the oxime to the amine with lithium aluminum hydride is significantly improved by the presence of titanium tetrachloride (78KGS1694). 

Write chemical equations that describe the following processes (a) the reduction of hematite in a blast furnace (b) the reduction of titanium tetrachloride to titanium metal (c) the removal of silica, Si02, from iron ore. 

Direct chemical reduction of titanium oxide, titanium chloride, titanium sulfate, or titanium hydride with carbon, nitrogen, or ammonia or by both carbon and nitrogen to form TiC, TiN and TiCN.3-6 Titanium nitride can also be prepared in a plasma jet from titanium tetrachloride and nitrogen.7... 

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