Reduction reactions Titanium chloride

Titanium Sulfates. Solutions of titanous sulfate [10343-61-0] ate readily made by reduction of titanium(IV) sulfate ia sulfuric acid solutioa by electrolytic or chemical means, eg, by reduction with ziac, ziac amalgam, or chromium (IT) chloride. The reaction is the basis of the most used titrimetric procedure for the determination of titanium. Titanous sulfate solutions are violet and, unless protected, can slowly oxidize ia coatact with the atmosphere. If all the titanium has been reduced to the trivalent form and the solution is then evaporated, crystals of an acid sulfate 3 Ti2(S0 2 [10343-61-0] ate produced. This purple salt, stable ia air at aormal temperatures, dissolves ia water to give a stable violet solutioa. Whea heated ia air, it decomposes to Ti02, water, sulfuric acid, and sulfur dioxide. 

An 80% yield of tetraphenylfuran is obtained by treatment of benzoyl chloride with active titanium generated by lithium aluminum hydride reduction of titanium trichloride (Scheme 84e) (8UOC2407). The reaction nroceeds via benzil and tetraphenylbut-2-ene-l,4-dione, both of which are minor products of 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... 

Titanium (IV) iodide may be prepared by a variety of methods. High-temperature methods include reaction of titanium metal with iodine vapor,1-3 titanium carbide with iodine,4 titanium(IV) oxide with aluminum (III) iodide,5 and titanium (IV) chloride with a mixture of hydrogen and iodine. At lower temperatures, titanium (IV) iodide has been obtained by the combination of titanium and iodine in refluxing carbon tetrachloride7 and in hot benzene or carbon disulfide 8 a titanium-aluminum alloy may be used in place of titanium metal.9 It has been reported that iodine combines directly with titanium at room temperature if the metal is prepared by sodium reduction of titanium (IV) chloride and is heated to a high temperature before iodine is... 

Although primary and secondary nitro compounds may be converted, respectively, to aldehydes and ketones by consecutive treatment with alkalis and sulfuric acid (Nef s reaction) the same products can be obtained by reduction with titanium trichloride (yields 45-90%) [565] or chromous chloride (yields 32-77%) [190]. The reaction seems to proceed through a nitroso rather than an aci-nitro intermediate [565] (Scheme 54, route b). 

As noted earlier, most classical antidepressant agents consist of propylamine derivatives of tricyclic aromatic compounds. The antidepressant molecule tametraline is thus notable in that it is built on a bicyclic nucleus that directly carries the amine substituent. Reaction of 4-phenyl-l-tetralone (18) (obtainable by Friedel-Crafts cyclization of 4,4-diphenyl butyric acid) with methyl amine in the presence of titanium chloride gives the corresponding Schiff base. Reduction by means of sodium borohydride affords the secondary amine as a mixture of cis (21) and trans (20) isomers. The latter is separated to afford the more active antidepressant of the pair, tametraline (20). 

Oxidation reactions r-Butyl hydroperoxide-Dialkyl tar-trate-Titanium(IV) isopropoxide, 51 m-Chloroperbenzoic acid, 76 Reduction reactions Chlorodiisopinocampheylborane, 72 Diisobutylaluminum hydride-Tin(II) chloride- (S) -1 - [ l-Methyl-2-pyrrolidi-nyljmethylpiperidine, 116 Lithium borohydride, 92 Lithium tri-sec-butylborohydride, 21 B-3-Pinanyl-9-borabicyclo[3.3.1]-nonane, 249... 

Lithium butyldimethylzincate, 221 Lithium sec-butyldimethylzincate, 221 Organolithium reagents, 94 Organotitanium reagents, 213 Palladium(II) chloride, 234 Titanium(III) chloride-Diisobutylalu-minum hydride, 303 Tributyltin chloride, 315 Tributyl(trimethylsilyl)tin, 212 3-Trimethylsilyl-l, 2-butadiene, 305 Zinc-copper couple, 348 Intramolecular conjugate additions Alkylaluminum halides, 5 Potassium t-butoxide, 252 Tetrabutylammonium fluoride, 11 Titanium(IV) chloride, 304 Zirconium(IV) propoxide, 352 Miscellaneous reactions 2-(Phenylseleno)acrylonitrile, 244 9-(Phenylseleno)-9-borabicyclo[3.3.1]-nonane, 245 Quina alkaloids, 264 Tributyltin hydride, 316 Conjugate reduction (see Reduction reactions)... 

Addition of traces of chloride in the form of bis(cyclopentadienyl)-titanium dichloride lowered the yield of polyethylene and initiated the known reduction reaction (129). Finally, it was found that polyethylene formation was caused by traces of water ( 10-8 mol%). Consequently, the yield increased to 500,000 g polyethylene per gram of titanium when two equivalents of trimethyl- or triethylaluminum previously treated with one equivalent of water was added to dimethylbis(cyclopentadienyl)ti-tanium (Table VII). 

ZrCl has a homoatomic-layer structure sequenced Cl-Zr-Zr-Cl. Each Zr atom has three neighbours in the adjacent sheet at 3.09 A, six more in the same sheet at 3.42 A and three chlorine atoms on the other side at 2.63 A. Weak chlorine-chlorine interactions between sheets at 3.61 A contrast with the strong metal-metal binding within sheets. These structural features account for the graphitic nature and anisotropic electrical conduction of ZrS. Thermodynamic parameters have been obtained for the reduction of zirconium chlorides. The reaction of ZrC with a melt containing alkali-metal chlorides and titanium chlorides has been investigated. ... 

Titanium(II) chloride has been prepared by the thermal decomposition of tita-nium(III) chloride and also by the reduction of titanium(IV) chloride with metals. This compound can be obtained in relatively high purity by the direct reaction of titanium(IV) chloride and hexamethyldisilane. The procedure described below is superior to the previously reported methods because simpler equipment is used and large quantities can be processed with a resultant saving in time. 

Alkenes can be obtained from aldehydes or ketones on reductive dimerization by treatment with a reagent prepared from titanium(III) chloride and zinc-copper couple (or L1A1H4), or with a species of active titanium metal formed by reduction of titanium(III) chloride with potassium or lithium metal. This McMurry coupling reaction is of wide application, but in intermolecular reactions generally affords a mixture of the E- and Z-alkenes (2.99). 

Yet another technique is used by the Titanium Metals Corporation of America. They tap off as much magnesium chloride as possible during the reduction reaction and then distil in situ from the reactor retort. A special design of stout reactor retort is required to withstand both the conditions of magnesium reduction and those of distillation, the latter involving high vacuum. 

The mechanism of the sodium reduction reaction is principally via the vapour phase, since the sodium tends to be volatile (b.p. 883°C) and to be boiling xmder reflux during the reaction. This reflux action of the sodium tends to wash the reactor walls free of titanium metal and sodium chloride, so that the disposition of sponge, after completion of a reaction, is different from that in the magnesium process. 

Attempts have been made to carry out the sodium reduction of titanium tetrachloride in other ways. For example, the reaction of the two vapours at a temperature of about 2000°C to give molten, or massive solid, titanium metal.2 - This reaction can be carried out in a vessel lined with sponge as in the National Smelting Company s patent applicable to titanium or zirconium. Alternatively, the low-temperature fluidization process has been used, in which titanium tetrachloride vapour reacts with a dispersion of 1 to 2 per cent of molten sodium, in a bed of titanium sponge and sodium chloride reaction products, at 200°C to 600°C, fluidized with a flow of pure argon. It is not known that these, or similar processes, have been operated on a commercial scale yet. 

The sodium reduction of titanium tetrachloride was actually carried out as early as 1939 in Germany, and about 670 kg was produced by the Deutsche Gold and Silber Scheideanstalt, during the 1939-45 war. The process, now obsolete, involved reduction in a molten bath of 50 per cent sodium chloride and 50 per cent potassium chloride at 800°C in an atmos phere of hydrogen. The reactors consisted of expendable welded sheet-iron cylindrical vessels, 50 cm diameter by 70 cm deep and 2 mm thick. These rested loosely in a stout iron crucible, fitted into a gas-fired furnace. A portable stirrer was used to agitate the reactor contents. Approximately 20 kg batches of titanium were reduced by distilling 85 kg of titanium tetrachloride at a controlled rate into a melt of 15 kg sodium chloride and 15 kg of potassium chloride, covered with a layer of 46 kg of molten sodium. The titanium sank to the bottom of the molten salts, and at the end of the reaction was recovered from the crushed solidified melt by leaching with dilute hydrochloric acid, in a ceramic-lined vessel. It was finally washed in water and dried at a moderate temperature. The same plant was also used for the production of zirconium metal by the sodium reduction of potassium fluorozirconate (KaZrF ]. 

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