Titanium trichloride, anhydrous

Titanium trifluoride is prepared by dissolving titanium metal in hydrofluoric acid (1,2) or by passing anhydrous hydrogen fluoride over titanium trihydrate at 700°C or over heated titanium powder (3). Reaction of titanium trichloride and anhydrous hydrogen fluoride at room temperature yields a cmde product that can be purified by sublimation under high vacuum at 930—950°C. 

Titanium Trichloride Hexahydrate. Titanium trichloride hexahydrate [19114-57-9] can be prepared by dissolving anhydrous titanium trichloride ia water or by reduciag a solutioa of titanium tetrachloride. Evaporation and crystallisation of the solution yield violet crystals of the hexahydrate. The hydrated salt has had some commercial appHcation as a stripping or bleaching agent ia the dyeiag iadustry, particularly where chlorine must be avoided. 

Asymmetric hydrogenation of nitrones in an iridium catalyst system, prepared from [IrCl(cod)]2, (S)-BINAP, NBu 4 BH4, gives with high enantioselectivity the corresponding A-hydroxylamines which are important biologically active compounds and precursors of amines (480). Further reduction of hydroxylamines to secondary amines or imines can be realized upon treatment with Fe/AcOH (479), or anhydrous titanium trichloride in tetrahydrofuran (THF) at room temperature (481). 

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. 

Because of its sensitivity toward oxygen and water, anhydrous titanium trichloride should always be handled under an inert atmosphere. The submitters report that titanium trichloride in bottles that have been opened and resealed undergoes a slow deterioration that causes erratic results in the coupling reaction. This decomposition is frequently detectable by the evolution of white fumes from the titanium trichloride during transfer. If a number of small-scale reactions are to be performed, the use of a Schlenk tube is advisable to extend the useful life of the titanium trichloride. 

A 500-mL, single-neck, round-bottom flask equipped with a reflux condenser and magnetic stirring bar is charged with 200 mL anhydrous tetrahydrofuran and 10.0 g (65mmole) titanium trichloride. The solution is heated to reflux for 22 hours, then allowed to cool to room temperature. The resulting pale-blue crystals are collected on a medium fritted funnel and washed with 50 mL dry pentane. The pentane wash plus another 50 mL dry pentane are added to the mother liquor to give a second crop of pale-blue solids. The total yield is 21.96 g (91.4%). 

The universal foam has not been tested in the public arena to the extent that results are available in the literature. Proprietary testing by product users has shown that it is highly effective as a vapor suppressant when used at an expansion ratio of 35-45 1. At this ratio, its expansion was good and its drainage time was 13-15 minutes. This foam has been tested on the following materials with favorable results trichlorosilane, di-methyldichlorosilane, phosphorus trichloride liquid, liquid hydrochloric acid, and titanium tetrachloride. Because of the quick vaporization rate of anhydrous ammonia and chlorine, no foam has been identified to date as being effective for all vapor suppression applications (Chubb National Foam, 1992b). 

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