Titanium chloride anhydrous

The activity of the catalyst in the olefin polymerization changes a wide range mainly with the variation of the number of ACs. This number depends on the nature and crystalline structure of the transition metal compound, the presence of a support and catalyst modifier, the nature of a cocatalyst, and the polymerization conditions. The most pronounced increase of the number of active centers (up to nearly half of the total content of titanium in the catalyst) is achieved by supporting titanium chlorides on anhydrous highly dispersed magnesium chloride. Catalysts of this type show the highest activity amongst all known catalytic systems used for olefin polymerization. 

The pinacol (94) was also obtained by reductive dimerization of retinaldehyde (2) with zinc amalgam (Reedy, 1968) or in the presence of chromium(III) salts (Sopher and Utley, 1979). With a mixture of lithium aluminum hydride and titanium chloride in anhydrous tetrahydrofuran, retinaldehyde (2) underwent reductive coupling to give p-carotene (Akiyama et al., 1979 Mukaiyama, 1977 McMurry et al., 1978 Ishida and Mukaiyama, 1977). 

To a solution of bicyclic vinylidenecyclopropane (1 0.5 mmol) in anhydrous dichloromethane (3 mL) under nitrogen atmosphere was added titanium chloride (TiCLi) (28.4 mg, 0.15 mmol) under a nitrogen atmosphere. The mixture was then stirred at room temperature for 2 h to complete the reaction. On completion of the reaction, the resulting mixture was concentrated and the residue was purified by flash chromatography to afford medium- and large-size naphthalenacarbocycle 2 with 78-87% yield. The products were characterized on the basis of detailed spectral studies. 

In recent years, highly active catalysts containing titanium chloride supported on anhydrous magnesium chloride have attracted extra attention " and have been intensively... 

Titanium tetrafluoride may be prepared by the action of elemental fluorine on titanium metal at 250°C (5) or on Ti02 at 350°C. The most economical and convenient method is the action of Hquid anhydrous HF on commercially available titanium tetrachloride in Teflon or Kynar containers. Polyethylene reacts with TiCl and turns dark upon prolonged exposure. The excess of HF used is boiled off to remove residual chloride present in the intermediates. 

Anhydrous aluminum chloride, AIQ, is manufactured primarily by reaction of chlorine [7782-50-5] vapor with molten aluminum and used mainly as a catalyst in organic chemistry ie, in Friedel-Crafts reactions (qv) and in proprietary steps in the production of titanium dioxine [13463-67-7] Ti02, pigment. Its manufacture by carbochlorination of alumina or clay is less energy-intensive and is the preferred route for a few producers (19). 

General Considerations. The following chemicals were commercially available and used as received 3,3,3-Triphenylpropionic acid (Acros), 1.0 M LiAlH4 in tetrahydrofuran (THF) (Aldrich), pyridinium dichromate (Acros), 2,6 di-tert-butylpyridine (Acros), dichlorodimethylsilane (Acros), tetraethyl orthosilicate (Aldrich), 3-aminopropyltrimethoxy silane (Aldrich), hexamethyldisilazane (Aldrich), tetrakis (diethylamino) titanium (Aldrich), trimethyl silyl chloride (Aldrich), terephthaloyl chloride (Acros), anhydrous toluene (Acros), and n-butyllithium in hexanes (Aldrich). Anhydrous ether, anhydrous THF, anhydrous dichloromethane, and anhydrous hexanes were obtained from a packed bed solvent purification system utilizing columns of copper oxide catalyst and alumina (ether, hexanes) or dual alumina columns (tetrahydrofuran, dichloromethane) (9). Tetramethylcyclopentadiene (Aldrich) was distilled over sodium metal prior to use. p-Aminophenyltrimethoxysilane (Gelest) was purified by recrystallization from methanol. Anhydrous methanol (Acros) was... 

Ferric chloride is largely produced as a by-product of pickling steel and of titanium dioxide pigment production. It can also be produced by direct methods. The traditional method, known as direct chlorination, produces anhydrous ferric chloride and involves the reaction of dry chlorine with red-hot iron. 

Unlike boron fluoride, titanium tetrachloride does not catalyze the liquid phase polymerization of isobutylene under anhydrous conditions (Plesch et al., 83). The addition of titanium tetrachloride to a solution of the olefin in hexane at —80° failed to cause any reaction. Instantaneous polymerization occurred when moist air was added. Oxygen, nitrogen, carbon dioxide, and hydrogen chloride had no promoting effect. Ammonia and sulfur dioxide combined with the catalyst if these were added in small quantity only, subsequent addition of moist air permitted the polymerization to occur. Ethyl alcohol and ethyl ether, on the other hand, prevented the polymerization even on subsequent addition of moist air. They may be regarded as true poisons. 

Anhydrous methylene chloride and titanium(IV) ethoxide (technical grade) were purchased from Aldrich Chemical Company. Inc., and used as received. 

The addition of a base, typically ammonia, to mixtures of transition metal halides and alcohols allows the synthesis of homoleptic alkoxides and phenoxides for a wide range of metals. Anhydrous ammonia was first used in the preparation of titanium alkoxides where the reaction is forced to completion by the precipitation of ammonium chloride.41 Although useful for the synthesis of simple alkoxides and phenoxides of Si, Ge, Ti, Zr, Hf, V, Nb, Ta and Fe, as well as a number of lanthanides,42-47 the method fails to produce pure /-butoxides of a number of metals.58 Presumably, secondary reactions between HC1 and Bu OH take place. However, mixing MC14(M = Ti, Zr) with the Bu OH in the presence of pyridine followed by addition of ammonia proves successful, giving excellent yields of the M(OBul)4 complexes.59... 

These ethers are stable to reducing and oxidising agents, to organometallic reagents, and to mildly acidic conditions that deprotect tetrahydropyranyl and silyl ethers (see below). They are deprotected by the action of either anhydrous zinc bromide or titanium(iv) chloride in dichloromethane solution.80... 

Reduction of nitroketones with titanium(m) chloride at pH 1. The foregoing nitroketone may be converted into the diketone by means of the following general procedure. The nitroketone in solution in tetrahydrofuran (0.2 m) is treated with 4 equivalents of titanium(m) chloride (1) (20% aqueous hydrochloric acid solution) and stirred under nitrogen at room temperature for 24 hours. The reaction mixture is then poured into ether and the phases separated. The aqueous phase is extracted several times with ether the organic extracts are combined, washed with 5 per cent sodium hydrogen carbonate and with brine, and then dried over anhydrous sodium sulphate, concentrated and distilled. The yield of heptane-2,5-dione is 66 per cent p.m.r. spectrum (CC14, TMS) 8 1.00 (t, 3H), 2.10 (s, 3H), 2.60 (s, 4H) and 3.41 (q, 2H). 

Imines are formed by the reaction of a primary amine with aldehydes or ketones with the simultaneous removal of water, for example by azeotropic distillation,213 by the addition of anhydrous sodium sulphate,214 by the addition of molecular sieves,215 or by the use of titanium(iv) chloride.216 When one, or both, of the reactants is aromatic, the imine is quite stable and usually known as a Schiff base (see Section 6.5.5, p. 902). In the case of wholly aliphatic reactants the imines tend to decompose or polymerise in these cases their further reaction is carried out without delay. 

A 2-L, three-necked, round-bottomed flask equipped with a mechanical stirrer with Teflon blades, thermometer, and nitrogen inlet is charged with 1.00 L of methylene chloride (Note 1) and 39.9 mL (38.1 g, 0.134 mol) of titanium(IV) isopropoxide (Note 2). The flask content is stirred and cooled under nitrogen in a dry ice-ethanol bath to -70°C. To the flask is then added 33.1 g (27.5 mL, 0.151 mol) of diethyl (2R,3R)-tartrate (Note 3) and 25.0 g (0.25 mol) of E-2-hexen-l-ol (Note 4). Asmall volume of methylene chloride is used to ensure complete transfer of each material to the reaction flask. To the flask is then added 184.5 mL (0.50 mol) of 2.71 N anhydrous tert-butyl hydroperoxide in toluene (Note 5) which has been precooled to -20°C (Note 6). The addition causes a temperature increase to -60°C the temperature of the reaction mixture is allowed to come to 0°C over a 2.0-hr period (Note 7). 

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