Crude titanium

Titanium is produced commercially by converting titanium oxide ore to titanium tetrachloride, then reducing it to produce a crude titanium product, //-tanium sponge. Titanium sponge can react with carbon dioxide to generate oxygen. 

Impurities in the rare metals produced by the iodide process can generally be reduced to a few tens of parts per million or less, for each element, provided care is taken in the selection of materials of construction. This initial advantage over other processes arises from the fact that the rare metals are produced without direct contact with a crucible or other container. Elements with volatile iodides should clearly be avoided in locations where the temperature is appropriate for attack by iodine vapour. Similarly, the crude feed should be as free from such elements as possible. For example, the whole of the zirconium impurity in a crude titanium feed would be carried over into the product, and vice versa, since the iodide process is equally suitable for the impurity as for the rare metal being purified. A large fraction of the iron and aluminium would be transferred, but decontamination factors from other elements such as nickel, chromium, carbon silicon and nitrogen are usually of the order of 10 to 100. 

The crude titanium is held in position by a molybdenum grid around the wall of the reactor, and is maintained at a suitable temperature. 100 to 200°C is satisfactory in practice for the production of titanium tetra-iodide at the maximum rate. If higher wall temperatures are used, the rate of deposition on the filament decreases, approaching zero at 400°C, since the system then contains entirely titanium di-iodide instead of tetra-iodide, produced by the reaction... 

The metal obtained from the Kroll process has the character of a crude titanium sponge. 

The gaseous crude titanium(IV)-chloride, boiling point 136 °C, is separated by fractionated condensation from other metal chlorides (SiCU, SnCU, VOCI2, FeGs, AICI3) and purified by vacuum distillation. The metal chlorides are neutralized with lime and deposited as hydroxides [342]. 

The titanium metal is obtained as crude titanium sponge, which is purified from magnesium by vacuum distillation to give pure titanium sponge. The magnesium metal... 

The highest purity titanium is prepared for research purposes by the iodide process. Crude titanium is first reacted with iodine in an inert atmosphere to form titanium iodide. This can then be decomposed at the surface of a heated titanium... 

A synthetically useful diastereoselectivity (90% dc) was observed with the addition of methyl-magnesium bromide to a-epoxy aldehyde 25 in the presence of titanium(IV) chloride60. After treatment of the crude product with sodium hydride, the yy -epoxy alcohol 26 was obtained in 40% yield. The yyn-product corresponds to a chelation-controlled attack of 25 by the nucleophile. Isolation of compound 28, however, reveals that the addition reaction proceeds via a regioselective ring-opening of the epoxide, which affords the titanium-complexed chloro-hydrin 27. Chelation-controlled attack of 27 by the nucleophile leads to the -syn-diastereomer 28, which is converted to the epoxy alcohol 26 by treatment with sodium hydride. 

A solution of 1.0 mmol of 2-acetyl alkenoate in 2.5 mL of CH2C1, is added slowly to a solution of 4.0 mmol of titanium(IV) chloride in 7.5 mL of CH-CL under an atmosphere of nitrogen at — 78 °C. The mixture instantaneously turns deep red. and is stirred at — 78 °C before being quenched by the addition of 5 mL of sat. aq potassium carbonate. The mixture is then partitioned between 10 mL of bt20 and 10 mL of water. The aqueous phase is extracted with three 10-mL portions of Et2(), and the extracts are combined, washed with 10 mL of brine, and dried over anhyd potassium carbonate. Concentration under reduced pressure gives the crude product. Product analysis is by capillary GC. 

In order to overcome the poor electrophilicity ofimines, nitrones arc used as partners for reaction with iron acyl enolates 428. Benzaldehyde phenylnitrone (5) reacts rapidly with the aluminum-based enolate at —78 C to give a crude /J-hydroxyamino iron acyl 6 (68% yield). Treatment with aqueous titanium trichloride in tetrahydrofuran at room temperature causes a selective reduction of the N—O bond and affords the /1-amino iron acyl 7 with inverse configuration compared to the addition ofimines (99% yield d.r. 11 23). 

Quaternary oxalkylated polycondensates can be prepared by esterification of an oxalkylated primary fatty amine with a dicarbonic acid. An organometallic titanium compound is used as a catalyst for condensation [842]. The reaction product is then oxalkylated in the presence of a carbon acid [841], These polycondensates can be used as demulsifiers for crude oil emulsions and as corrosion inhibitors in installations for the production of natural gas and crude oil they can and also be used in processing. 

Two processes are used in the manufacture of titanium dioxide pigments the sulfate process and the chloride process. The chemistry of the sulfate process, the longer established of the two methods, is illustrated schematically in Scheme 9.1. In this process, crude ilmenite ore, which contains titanium dioxide together with substantial quantities of oxides of iron, is digested with concentrated sulfuric acid, giving a solution containing the sulfates of Ti(iv), Fe(m) and Fe(n). Treatment of this... 

MP borohydride catches one equivalent of the titanium catalyst, while the polystyrene-bound diethanolamine resin (PS-DEAM) can scavenge the remaining titanium catalyst. The borohydride reagent also assists in the reductive animation reaction. Final purification of the crude amine product is achieved with a polystyrene-bound toluene sulfonic acid resin scavenger that holds the amine through an ion exchange reaction, while impurities are washed off. The pure amine can be recovered with methanol containing 2M ammonium hydroxide. 

The first ever injectable crude biomaterial, that is a dental implant, appeared early in ad 6oo (Fig. 12.1). During those times, Mayan people trimmed seashells into artificial teeth to replace missing teeth (Michael, 2006 Ratner et al., 2004). Early biomaterials also led to problems, including sterilization, toxicity, inflammation, and immunological issues. Since the Mayan s initial use of artificial teeth, biomaterials have evolved to be used in modem artificial hearts, hip and knee pros-theses, artificial kidneys, and breast implants. Materials used in these applications include titanium, silicons, polyurethanes, teflon, polybiodegradable polymers, and most recently bio-nanomaterials (Pearce et al., 2007)... 

Generally, most resids and asphalt have 79 to 88% w/w carbon, 7 to 13% w/w hydrogen, trace to 8% w/w sulfur, 2 to 8% w/w oxygen, and trace to 3% w/w nitrogen. Trace metals such as iron, nickel, vanadium, calcium, titanium, magnesium, sodium, cobalt, copper, tin, and zinc occur in crude oils. Vanadium... 

The chiral enolate-imine addition methodology was examined in detail (Thiruvengadam et al., 1999). Enolate formation proceeds to completion within an hour at temperatures from — 30 to 0°C with either 1 equiv. TiCl4 or TiClaO-iPr (preformed or prepared in the presence of substrate by addition of TiCl4 and followed by a third of an equivalent Ti(0-iPr)4 and two equivalents of a tertiary amine base). Unlike the aldol process with the same titanium enolate, the nature of the tertiary amine base had no effect on the diaster-eoselectivity. The diastereoselectivity is maximized by careful control of the internal temperature to below — 20°C during the imine addition (2 equiv.) as well as during the acetic acid quench. The purity of the crude 2-amino carboxamide derivatives (17a or... 

It has been pointed out that the product obtained by treating certain samples of ground a-titanium trichloride (particularly those which contain traces of TiCU or other Ti(IV) compounds) with radioactive alkylalu-minum, shows a certain degree of radioactivity also after submitting it to the action of an acid or an alcohol in an attempt to decompose the metal-carbon bonds. Such radioactivity is due to a contaminant, the nature of which depends on the degree of purity and the amount of crude a-titanium trichloride employed. It generally decreases, eventually attaining very low values if the crude a-titanium trichloride is repeatedly washed with anhydrous benzene before its use. 

Crude elemental silicon can be obtained by reduction of silica sand with coke in the electric furnace (reaction 17.33) and may be adequate for making ferrosilicon alloys (Section 16.7.5) or silicones (Section 3.5). The high purity silicon used for electronic chips can be made from silica via silicon tetrachloride, which, like TiCU, is a volatile liquid (bp 57 °C) susceptible to hydrolysis but readily purifiable by fractional distillation. Indeed, the procedure for silicon resembles the Kroll process for titanium, except that an argon atmosphere is not necessary ... 

Some of the metallic constituents were somewhat soluble in the propane-oil portion, but all tended to be concentrated in the asphaltic portion. Although vanadium (0.02% by weight in the original crude petroleum) was present in all fractions, the greater part was found in the cyclohexane and benzene fractions. From the similarity of the absorption spectra of the vanadium concentrates from petroleum and those of synthetic vanadium porphyrin complexes, Skinner arrived at the conclusion that vanadium compounds from the petroleum of the Santa Maria Valley Field in California exist as porphyrin complexes. Additional metallic constituents were detected by Skinner as these became concentrated in the various solvent fractions, including aluminum, titanium, calcium, and molybdenum. 

Pyrochlore.—This is a crude calcium niobate which may also contain appreciable quantities of titanium, thorium and cerium, together with smaller quantities of iron, magnesium, the alkali metals, and fluorine. It does not contain chlorine, and it is of interest in that some specimens are remarkably free from tantalum. It occurs in Norway and near Miask in the Ural Mountains. The ore is brown, forms regular octa-... 

---