TiCl2, Titanium chloride

ThN404CMH42, Thorium, bis(2,4-pentane-dionato)[5,10,25,20-tetraphenylpor-phyrinato(2—)]-, 22 160 TiClC ( io,Titanium(lII)7chlorobis( q -cyclo-pentadienyl)-, 21 84 TiCl2> Titanium chloride, 24 181 TiCl]0]Ci2H24, Titanium(III), trichlorotris-(tetrahydrofiiran), 21 137 TiCl402C8H , Titanium(rV), tetrachlorobis-(tetrahydrofuran)-, 21 135 TiFeHi 4, Iron titanium hydride, 22 90 TiHNbOs, Hydrogen, pentaoxoniobatetita-nate(l-), 22 89... 

The conclusion may be drawn that the data obtained of comparative studies of olefin polymerization by the one-component catalyst (TiCl2) and two-component systems (TiCl2 + AlEtxCl ) confirm the concept of monometallic active centers on the surface of titanium chlorides developed by Cossee and Arlman (170-173). 

Thus, the experimental data show that the composition of catalytic systems does not influence the stereoregularity of the corresponding polymer fractions but only their relative content. Hence, the stereospecificity of the active centers of these catalysts is the same including the one-component catalyst TiCl2. This confirms the concepts on the monometallic character of AQ in the Ziegler-Natta catalysts. The possible existence of chiral titanium atoms on the titanium chloride surface was studied by Cossee and Arlman ... 

Titanium forms dihalides TiXj, for example titanium(II) chloride, formed by heating titanium metal and the tetrachloride to about 1200 K. TiCl2 is a black solid, which disproportionates on standing to TiCl4 + Ti. Since it reduces water to hydrogen, there is no aqueous chemistry for titanium(II). A solid oxide TiO is known. 

The Stock Oxidation-Number System. Stock sought to correct many nomenclature difficulties by introducing Roman numerals in parentheses to indicate the state(s) of oxidation, eg, titanium(II) chloride for TiCl2, iron(II) oxide for FeO, titanium(III) chloride for TiCl, iron(III) oxide for Fe203, titanium(IV) chloride for TiCl, and iron(II,III) oxide for Fe O. In this system, only the termination -ate is used for anions, followed by Roman numerals in parentheses. Examples are potassium manganate(IV) for K2Mn02, potassium tetrachloroplatinate(II) for K PtCl, and sodium hexacyanoferrate(III) for Na3Fe(CN)3. Thus a set of prefixes and terminations becomes uimecessary. 

Other methods iaclude hydrogen reduction of TiCl to TiCl and TiCl2 reduction above the melting poiat of titanium metal with sodium, which presents a container problem plasma reduction, ia which titanium is collected as a powder, and ionized and vaporized titanium combine with chlorine gas to reform TiCl2 on cool-down and aluminum reduction, which reduces TiCl to lower chlorides (19,20). 

When more than the stoichiometric amount of AlEt3 is used to reduce TiCl4, in particular at Al/Ti ratios higher than 0.45, the reaction product is not brown or purple and crystalline anymore but black and amorphous (4). Under such conditions TiCl4 is overreduced with formation of miscellaneous titanium compounds of valence < 3 containing TiCl2 and possibly also some alkyltitanium chloride (10,18). 

Titanium(IV) Chloride, the red-brown mixture was wanned to room temperature, and the ether removed in vacuo. Dry benzene was added and the nondissolved solid was separated via filtration under nitrogen. Removal of the solvent delivered 50% of a sensitive red-brown solid which showed a single set of NMR signals (eq 17). The BINOL-TiCl2 thus obtained was utilized to prepare the cyanohydrin of 3-methylbutanal in <82% ee (eq 18). 

A chiral titanium complex with 3-cinnamoyl-l,3-oxazolidin-2-one (2d) was isolated by Jorgensen et al. from a mixture of TiCl2(0-z-Pr)2 with (2R,3R)-2,3-0-isopropylidene-l,l,4,4-tetraphenyl-l,2,3,4-butanetetrol (1-Me) which is an iso-propylidene acetal analogue of 1 [35]. The structure of the complex was determined by X-ray methods. The complex consists of the isopropylidene diol 1-Me and the cinnamoyloxazolidinone 2d in the equatorial plane and the two chloride ligands in the apical (trans) position as depicted in structure A (Scheme 3). It appears from this structure that the pseudo-axial phenyl group of the chiral ligand seems to block one face of the coordinated 2d. In contrarst, from an NMR study of the complex in the solution, Di Mare et al. reported that the above trans... 

Thus the reaction of sodium chloride with titanium from the alloy, or rutile from the scale leads to the formation of TiCl2, Na2Ti03, HC1 and Cl2.This list of reactions is by no means exhaustive, and may also involve reaction with other alloying additions which may be substituted for the titanium metal. Particularly, the role of aluminium must be of importance. A thermodynamic analysis by Travkin et al. [32] confirms that complex oxide scales are formed when titanium and its alloys react with NaCl. Particularly that the formation of volatile metallic chlorides are thermodynamically favourable, especially for alloying additions Zr, Mo and Al. The subsequent pyrohydrolysis of these metal chlorides results in the formation of HC1 gas, particularly with Mod., and AlClj. Furthermore, such pyrohydrolysis of halide salts may be accelerated by the presence of alumina within the scales, which acts as a catalyst [25]. 

To improve capacity we have investigated the use of Ti-halides other than TiCl3 to catalyze hydrogen absorption and desorption in NaAlH4. Titanium triflouride (TiF3) and TiCl2 appear to work equally as well as TiCl3 and reduce the overall capacity loss due to the formation of sodium chloride (NaCl) or sodium flouride (NaF). 

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