Cyclopentadienyl-titanium dichloride

Phase-Transfer-Catalyzed Modification of Dextran Employing Dibutyltin Dichloride and Bis(cyclopentadienyl)titanium Dichloride... 

Titanocene (Cp2TiR2) /alkyllithium (LiR) Styrene, butadiene or isoprene copolymers PB in cyclohexane and toluene (5 wt.%) Catalyst (bis(cyclopentadienyl) titanium dichloride) 0.4 mmol per 100 g PB PH2 0.49 MPa T 40 °C t 2 h Conversion 97% Asahi Kasei Kogyo Kabushiki Kaisha (Osaka, Japan) 62 (1985)... 

Titanocene dichloride ALDRICH Bis(cyclopentadienyl)titanium dichloride Titanium, dichloro-n-cyclopentadienyl- (8) Titanium, dichlorobis(r -2,4-cyclopentadienyl-1-yl)- (9) (1271-19-8)... 

Bis(2-chloroethoxy)ethane Ethane, 1,2-bis(2-chloroethoxy)- (112-26-5), 68, 227 Bis(cyclopentadienyl)titanium dichloride Titanium, dichloro-x-cyclopentadienyl- ... 

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). 

In addition to the metallocenes described previously, so-called halfsandwich compounds or constrained-geometry catalysts (Fig. 3) such as dimethylsilyl-t-butylamido cyclopentadienyl titanium dichloride are used. These catalysts are excellent for producing polyethylenes with long-chain branching and can incorporate high amounts of comonomers such as 1-octene... 

D. S. Breslow, and N. R. Newburg, Bis(cyclopentadienyl)titanium Dichloride-Alkyla-luminium Complexes as Catalysts for the Polymerization of Ethylene, J. Am. Chem. Soc. 79, 5072-5073 (1957). 

At the present time, the most likely concept of the mechanism of a heterogeneous polymerization catalyzed by a Ziegler-Natta catalyst involves a complex in which the organometallic component and the transition metal component—i.e., the A1 and Ti atoms—are joined by electron-deficient bonds. Natta, Corradini, and Bassi (13) have reported such a structure for the active catalyst prepared from bis (cyclopentadienyl) titanium dichloride and aluminum triethyl. Natta and Pasquon (14), Patat and Sinn (18), and Furukawa and Tsuruta (2) have proposed mechanisms for the stereospecific polymerization of a-olefins in terms of such electron-deficient complexes. 

For the preparation of cyclopropanes from transition-metal complexes see Section 5.2.6., p 1849. Various transition-metal complexes are able to undergo addition to the exocyclic double bond of methylenecyclopropanes with formation of a (7 bond between the carbon and metal atoms. A variety of methylenecyclopropanes with one or two methyl groups in positions 1 and 2 were reacted with bis(cyclopentadienyl)titanium dichloride and isopropylmagnesium bromide to give the corresponding neutral bis(cyclopentadienyl)cyclopropylmethyltitanium(III) compounds 1 in yields ranging from 23 to The carbon-metal [Pg.1512]

In contrast to the heterogeneous catalyst, the soluble catalysts appear to have well-defined structures. For example, the soluble catalyst system generated from triethyl aluminum and bis(cyclopentadienyl)titanium dichloride has been shown by elemental and x-ray analysis to have a halogen-bridged... 

A number of Ti-MCM-41 materials were synthesised according to published procedures and evaluated for activity in the oxidation of methyl glucoside in aqueous medium. Only the material which had been synthesised by Maschmeyer et al., whieh involves post-synthesis modification of all silica MCM-41 by bis-(cyclopentadienyl)titanium dichloride, showed activity towards methyl glucoside. The conversion was low, however, because a vigorous decomposition of hydrogen peroxide predominated. We considered that this might be caused by crowding of the... 

In aqueous medium in the presence of hydrogen peroxide the titanium leaches easily out of Ti-MCM-41 synthesised by impregnation by bis-cyclopentadienyl titanium dichloride of an all silica MCM-41. The dissolved titanium eatalyses the oxidation of methyl a-D-glucopyranoside to 1-0-methyl glucuronic acid. This product is sensitive to further oxidation to formic, glycolic and tartronic acid. In the oxidation of sucrose and trehalose monocarboxylate are probably formed beside C - C4 mono-and dicarboxylates. 

M. Williams, C. Carraher, Comparative Infrared and Raman Spectroscopy of the Condensation Product of Squaric Acid and Bis(cyclopentadienyl)titanium Dichloride, in Inorganic and Metal-Containing Polymeric Materials, J. Sheats, C. Carraher, C. Pittman, Jr., M. Zeldin, B. Currell, Eds., pp. 295-318, Plenum Publishing, New York, 1995. 

They also found that mixtures of bis-(cyclopentadienyl)-titanium dichloride and aluminum triphenyl or bis-(cyclopentadienyl)-titanium diphenyl and aluminum triethyl were active catalysts, and presumably formed similar, bridged complexes. Interestingly, the hydrocarbon substituent attached to aluminum became an end group in the polymer. 

Titanium enolates generated with bis(cyclopentadienyl)titanium dichloride show anti/threo selectivity (Scheme 43), although the corresponding zirconium enolates (vide infra) react syn selectively. 

Some of the steps in the above sequence of reactions are reduction steps in which the transition metal is reduced to a low valency state possessing unfilled ligand sites. The reduction steps are very important as the low-valency transition metal species are believed to be the real catalysts or precursors of real catalysts. For heterogeneous catalysts, the reactions are, in fact, more complicated than those shown above. Radicals formed in these reactions may be removed by different processes such as combination, disproportionation, or reaction with solvent. Unlike heterogeneous catalysts, the soluble catalysts appear to have well defined structures. For example, the soluble catalyst system that is obtained by the reaction of triethyl aluminum and bis(cyclopentadienyl)titanium dichloride is known by elemental and X-ray analysis to have a halogen-bridged structure (I) ... 

TERPENOIDS Bis(cyclopentadienyl)titanium dichloride. Palladium chloride. 

Bis(cyclopentadienyl)titanium dichloride (Titanocene dichloride), (Ti -CsHs) -TiClj. Mol. wt. 249.00, m.p. 289-291°, red, air stable. Suppliers Alfa, ROC/RIC, Strem. 

TERPENOIDS Bis(cyclopentadienyl)titanium dichloride. Palladium chloride. 1,2,4,5-TETRAENES Cuprous chloride. 

CA), bis-cyclopentadienyl titanium dichloride, BCTD (Aldrich, Milwaukee, WI) indole-3-butyric acid, IPA, (Aldrich) and indole-3-propronic acid, IPA, (Aldrich). 

COMPARATIVE INFRARED AND RAMAN SPECTROSCOPY OF THE CONDENSATION PRODUCT OF SQUARIC ACID AND BIS(CYCLOPENTADIENYL)TITANIUM DICHLORIDE... 

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