Black Mixture

Color Concentrates. Color concentrates have become the method of choice to incorporate colorants into resins. Color concentrates have high ratios of colorant to a compatible vehicle. The colorant may be added at 70% colorant to 30% vehicle in a titanium dioxide mixture whereas the ratio may be 15% colorant to 85% vehicle in a carbon black mixture. The amount of colorant that can be added is dependent on the surface area and the oil absorption of the colorant and the wetting abiHty of the vehicle. The normal goal is to get as much colorant in the concentrate as possible to obtain the greatest money value for the product. Furthermore, less added vehicle minimizes the effect on the physical or chemical properties of the resin system. 

A solution of trimethylsilyl lithium (10 mmol) in HMPA (CAUTION— CANCER SUSPECT AGENT) (5 ml) and ether (10 ml, from the MeLi) prepared as above was cooled to 0°C and diluted with THF (20 ml). Copper(i) cyanide (5 mmol) was added in one portion, and the resulting black mixture was stirred at 0°C for 20min. 

A technique of developing Aniline Black directly on the fiber was found by Lightfoot in the period between 1860 and 1863. In accordance with this process, the fiber is soaked with aniline, aniline hydrochloride, and sodium chlorate in the presence of an oxidation catalyst (e.g., ammonium vanadate, potassium hexa-cyanoferrate(II)). The compound is developed at 60 to 100°C and then oxidized further with sodium chromate. It should be noted, however, that Perkin had already synthesized a black compound which he called Aniline Black as early as 1856. He oxidized aniline (containing toluidine) with potassium dichromate and separated Aniline Violet from the resulting black mixture (Aniline Black). 

Allene must not be allowed to condense in the reaction vessel prior to the introduction of the BBr3. Boron tribromide reacts rapidly and exothermically with liquid allene to give a black mixture that yields very little of the desired product. In one experiment in which the connection between the Tedlar bag and the reaction vessel... 

Checking for photometric linearity by the use of a set of transmittance or reflectance standards (e.g. Spectralon, carbon black mixtures). 

In an apparatus set up for steam distillation and containing a rapidly stirred solution of 5.0 gm (0.023 mole) of jV-benzoylphenylhydroxylamine (N-phenylbenzohydroxamic acid) in 100 ml of a 1 1 solution of ethanol-acetic acid, cooled to —20°C, is added 11.5 gm (0.024 mole based on 94% purity) of lead tetraacetate in one portion. After approximately 10 sec (when the initial green color just begins to darken), 100 ml of water is added and the brown or black mixture is rapidly subjected to steam distillation. The distillate is collected in a receiver filled with chopped ice. The product is isolated by filtration of the distillate. Finally, it is dried by pressing dry between filter papers to yield 1.4-2.0 gm (56-80%), m.p. 66°-68°C. 

Method B. (THF)3Li[Si(SiMe3)3] (5.0 g, 11 mmol) and tellurium powder (1.3 g, 11 mmol) are combined in a 100-mL, round-bottomed Schlenk flask equipped with a magnetic stir bar. The flask is cooled to 0°C, THF (50 mL) is added via cannula, and stirring is initiated. The ice bath is removed and the orange mixture is stirred at room temperature for 1 h. Trifluoromethanesulfonic acid (0.94 mL, 11 mmol) is added dropwise and the resulting black mixture is stirred for 2 h. Using the workup and purification procedure described in Method A yields 2.2 g (56%) of colorless, waxy product. 

Sodium was stored under mineral oil and washed with pentane before use. For convenience the checkers used 1/6 to 1/4 inch sodium spheres (Matheson Coleman and Bell) that were weighed in mineral oil, then wiped free of oil, rinsed in hexane, cut in half, rinsed in hexane again, and immediately added to the reaction over a 2-hr period, during which time the dark-black mixture became extremely viscous. 

Substitution of the first benzene nucleus by electron acceptors also causes bathochromic shifts. Disazo dyes of this type such as 6 are frequently incorporated as components of black mixtures. 

Cool the C8K powder to ambient temperature, suspend it in anhydrous THF (30 mL), and add a mixture of finely ground anhydrous ZnCI2 (2 g, 14.7 mmol) and AgOAc (0.2 g, 1.2 mmol) under a stream of Ar in one portion to the rapidly stirred suspension. The ensuing exothermic reduction causes the solvent to boil. Once the reaction has ceased, reflux the black mixture for 30 min in order to ensure quantitative reduction of the zinc and silver salts. 

PbPd02. The black PbPd02 is prepared conveniently by heating a 1 1 PbO-Pd black mixture in air at about 600°-700°C for several days. 

Methyl l-Methoxyltellurobenzoate)1 A solution of 0.171 g (1 mmol) 2-methoxybenzoyl chloride in 8 ml tetrahydrofuran is added to 0.174 g (1 mmol) of freshly prepared sodium telluride (liquid ammonia method). The mixture is stirred at 0° for 1 h and then filtered. The solvent is evaporated from the filtrate under reduced pressure. The red, oily residue is cooled to — 63° under nitrogen and mixed with 2 ml (32 mmol) iodomethane. The mixture is warmed to — 30° and stirred at this temperature for 2 h. The excess iodomethane is evaporated under reduced pressure below 0°. The residue is treated with 5 ml dichloromethane, the black mixture is filtered, and the filtrate evaporated under reduced pressure below 0° to give yellow crystals yield 84% m.p. 25°. 

Fractional crystallization (or differential crystallization) is a process whereby two chemically compounds that form crystals with slightly different solubilities in some solvent (e.g., water) can be separated by a "tree-like" process. One should remember the herculean work by Marie Curie3, who by fractional crystallization isolated 0.1 g of intensely radioactive RaCl2 from 1 ton of pitchblende (a black mixture of many other salts, mainly oxides of uranium, lead, thorium, and rare earth elements). 

The crude bromo ester is mixed with 82.5 ml. (0.70 mole) of pure quinoline (Note 3) in a 250-ml. round-bottomed flask equipped with an air condenser, and the mixture is heated for 3 hours with an oil bath maintained at 160-170°. The black mixture is cooled, treated with 150 ml. of 20% hydrochloric acid, then shaken thoroughly with 200 ml. of petroleum ether (Note 2) until most of the tarry material has dissolved (Note 4). The aqueous phase is separated and washed with an additional 200 ml. of petroleum ether, and the combined organic extracts are washed with 10% hydrochloric acid and then with water. This washing cycle is repeated until the washes are colorless (two acid washes usually suffice) finally, the petroleum ether solution is washed once more with water. The organic layer is dried over anhydrous sodium sulfate, the solvent is flash-distilled as described above, and the residual liquid ester is distilled through a 61-cm. Pod-bielniak-type column (Note 5). The colorless unsaturated ester (Note 6) distils at 153-154°/14.5 mm. after a small fore-run. The yield is 22-27 g. (70-85.5% based on 2-methyldodecanoic acid), 1.4520-31, Xmax 214 me 12,300, in hexane (Note 7), Xmax 217 mii, e 12,800, in 95% ethanol. 

Allow the black mixture to cool down. Pour it into a 500 mL round-bottomed flask. 

The conversion of Hg2Cl2 by dilute NH4OH solution into the insoluble black mixture of mercury amido chloride, Hg(NH2)Cl, and finely divided mercury. 

Aqua regia converts the black mixture into HgCl2 (see under Mercury, Section III.5, reaction 1). Mercury(II) is then detected with SnCl2 solution. 

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