Titanium compound

Kirk-Othmer Encyclopedia of Chemical Technology (4th Edition) 

Titanium, Ti, atomic number 22, relative atomic mass 47.90, is the ninth most common element (ca 0.6% by weight) and is widely distributed in the earth s cmst. It is found particularly in the ores mtile, Ti02, and ilmenite, FeTiO.  

Titanium is the first member of the t7-block transition elements. Its electron configuration is [Ar] and successive ionisation potentials are 6.83, 

Data relating to changes of state of selected titanium compounds are Hsted in Table 1. Heats of formation, free energy of formation, and entropy of a number of titanium compounds at 298 and 1300 K are collected in Table 2. 

Melting and sublimation temperatures are generally based on those given in Ref. 15. 

Relative Cutting Performance of Coatings for High-speed Steel Tools 

The main applications of coated cemented carbides are tips and blanks, indexable inserts, milling tools, turning, and boring tools and circular saws. 

Five phases of titanium boride have been reported. TiB2 [12405-65-35], TL,B [12505-68-9], TiB [12007-08-8], TL,B5 [12447-59-5], and TiB12 [51311-04-7]. The most important of these is the diboride, TiB2, which has a hexagonal structure and lattice parameters of a = 302.8 pm and c = 322.8 pm. Titanium diboride is a gray crystalline solid. It is not attacked by cold concentrated hydrochloric or sulfuric acids, but dissolves slowly at boiling temperatures. It dissolves more readily in nitric acid/hydrogen peroxide or nitric acid/sulfuric acid mixtures. It also decomposes upon fusion with alkali hydroxides, carbonates, or bisulfates. 

Plesch s group dso studied the polymerisation of styrene by the combination TiCl4—The internal order in monomer was found to be close to two and the external order, based on initial polymerisaticai rates, also two. The initial rate of polymerisation depended on the first power of water concentration for (H2O] [H20]c, but became independent of it for [H2O] [H20]c, (H20]c being an empirical value. Further monomer additions at the end of the first polymerisation resulted in a new reaction proceeding at the same rate as the first one. The effect of temperature on the initial polymerisation rate was unusual in that a decrease was observed between —30 °C and about —45 °C, and an increase below this range. All the above observa- 

A few comments are in order concerning the peculiarities of experiments conducted on the copolymerisation of isobutene with aromatic olefins both by Plesch s and Sigwalt s groups In the first study addition of water to a quiescent mixture resulting from the incomplete ct olymerisation of isobutene and styrene promoted by the TiCl4—H2O pair, reinitiated the copolymerisation, and this was taken as evidence for the need of water cocatdysis in the polymerisation of styrene. 

Iaues indicating the concerted intermediate. In this sequence of equilibria the rate determining step is probably the proton transfer on the doible bond to give the active species. 

The authors of this very interesting paper also carried out a detailed kinetic study of the course of the prJymerisation and showed that the concentration of active species went throu a maximum value and then decreased with time both at —50 and —30 °C. This behaviour accounts for the fact that at those temperatures the conversiontime curves were S-shaped. 

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ANTIBIOTICS - NUCLEOSIDES AND NUCLEOTIDES] (Vol 3) -titanium dioxide in [TITANIUM COMPOUNDS - INORGANIC] (Vol24)... 

Titanium trifluoride [13470-08-17, TiF, is a blue crystalline solid that undergoes oxidation to Ti02 upon heating in air at 100°C (see Titanium compounds). In the absence of air, disproportionation occurs above 950°C to give TiF and titanium metal. TiF decomposes at 1200°C, has a density of 2.98 g/cm, and is insoluble in water but soluble in acids and alkafles. The magnetic moment is 16.2 x 10 J/T (1.75 -lB). 

Although titanium compounds are considered to be physiologicaHy inert (21), fluorides in general are considered as toxic above 3 ppm level and extreme care should be taken in handling large amounts of titanium salts as weU as hexafluorotitanic acid. The ACGIH adopted (1992—1993) toxicity limits are as TWA for fluorides as F 2.5 mg/m. ... 

Commercial metal anodes for the chlorine industry came about after the late 1960s when a series of worldwide patents were awarded (6—8). These were based not on the use of the platinum-group metals (qv) themselves, but on coatings comprised of platinum-group metal oxides or a mixture of these oxides with valve metal oxides, such as titanium oxide (see Platinum-GROUP metals, compounds Titanium compounds). In the case of chlor-alkaH production, the platinum-group metal oxides that proved most appropriate for use as coatings on anodes were those of mthenium and iridium. 

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