Gallium chloride

Hydrolysis. 1,1,1-Trichloroethane heated with water at 75—160°C under pressure and in the presence of sulfuric acid or a metal chloride catalyst decomposes to acetyl chloride, acetic acid, or acetic anhydride (54). However, hydrolysis under normal use conditions proceeds slowly. The hydrolysis is 100—1000 times faster with trichloroethane dissolved in the water phase than vice versa. Refluxing 1,1,1-trichloroethane with ferric and gallium chloride... 

Galli-. gallic (relating to trivalent gallium), -chlorid, n. gallic chloride, gallium (III) chloride. 

With gallium chloride, ferric chloride and antimony pentachloride the rate coefficients were dependent upon the concentration of chlorobenzene and the square of the concentration of the catalyst, but the third-order coefficients varied with the initial concentration of the catalyst (Table 103)394. The overall kinetic equation was, therefore,... 

Preliminary studies on the dimeric complex [But(H)Ga(/i-NEt2)]2, prepared by the addition of four equivalents of B Li to the gallium chloride complex [Cl2Ga(/i-NEt2)]2, proved to be air stable and produced gallium-rich GaN films at deposition temperatures as low as 250 °C using CVD. However, it was necessary to add an external nitrogen source in order to obtain 1 1 GaN films.279... 

The reduction of di(neopentyl)gallium chloride with lithium naphthalide was reported to afford the gallium clusters (Ga-CH2CMe3) , but their structures are hitherto unknown. It was assumed that different species with up to 12 gallium... 

The transitory existence of alkylcarbonium ions in alkyl halide-Lewis acid halide systems has been inferred from a variety of observations, sueh as vapour-pressure depressions of OHsCl and C2H5CI in the presence of gallium chloride (Brown et al., 1950), the electric conductivities of aluminium chloride in ethyl chloride (Wertyporoch and Firla, 1933) and of alkyl fluorides in boron trifluoride (Olah et al., 1957), as well as the... 

Borovik, A. S. Bott, S. G. Barron, A. R. Arene-Mercury Complexes Stabilized Aluminum and Gallium Chloride Synthesis and Structural Characterization. J. Am. Chem. Soc. 

In the presence of gallium chloride, aluminum bromide, aluminum chloride, and ferric chloride, benzoyl azide is decomposed according to eq 2. Here complex formation is very fast, and the decomposition of the complex is the ratedetermining step. The halides do not complex with the phenyl isocyanate formed and, as a consequence, they are not consumed in the reaction. As long as benzoyl azide is in excess, the concentration of the complex is equal to the halide concentration and remains constant. The experimentally determined pseudo-zero-order rate constant depends therefore upon the first power of the initial halide concentration. When, however, the reaction is at a stage where the azide is no longer in excess, the rate of the reaction becomes first order with respect to benzoyl azide and zero order with respect to halide. PhCONj + AlBr, -r - PhCONrAlBr, r+-... 

The halides, GaQs, AlBrs, A1C13, and FeCl3, very probably also exist in dimeric form. With these halides, however, the complexation reaction with the azide is the fast step so that no square-root term is found in the kinetic equation. Arsenic trichloride, arsenic tribromide, phosphorus trichloride, and phosphorus pentachloride were without effect on the rate of decomposition of benzoyl azide. Finally, the authors have observed that the catalytic influence of boron tribromide was much higher than all the other halides. Its rate constant was estimated to be about 18 times larger than that for gallium chloride. 

Purification. Extraction from aluminum or zinc ores produces cmde gallium metal or concentrates. These concentrates are transformed to sodium gallate, gallium chloride, or gallium sulfate solutions which are purified, then electrolyzed. Gallium is deposited as a liquid. 

WW. C. Johnson and C. A. Haskew, Inorg. Synth., 1,26 (1939), present details of the gallium chloride synthesis. 

Ga+++ (aq.). This value is obtained from that for aqueous gallium chloride. 

Gallium chloride, as Lewis acid, 9, 741 Gallium compounds... 

Alkynes 258 reacted with disulfides 259 in the presence of gallium chloride, in benzene at 0°C for 30 min, to give disulfides 260 in good yield (Scheme 73). The mechanism of formation of 260 is shown in Scheme 74. Thiirenium ions 261, generated from 262 and alkynes, undergo nucleophilic substitution to give 260 <20040L601>. 

---