Norit acid washed, preparation

In a tall 1-1. beaker is placed an intimate mixture of 53 g. (0.25 mole) of freshly prepared acetophenonephenylhydrazone (Note 1) and 250 g. of powdered anhydrous zinc chloride (Note 2). The beaker is immersed in an oil bath at 170°, and the mixture is stirred vigorously by hand. The mass becomes liquid after three to four minutes, and evolution of white fumes begins. The beaker is removed from the bath and the mixture is stirred for five minutes. In order to prevent solidification to a hard mass, 200 g. of clean sand is thoroughly stirred into the reaction mixture. The zinc chloride is dissolved by digesting the mixture overnight on the steam cone with 800 cc. of water find 25 cc. of concentrated hydrochloric acid (sp. gr. about 1.2). The sand and crude 2-phenylindole are removed by filtration, and the solids are boiled with 600 cc. of 95 per cent alcohol. The hot mixture is decolorized with Norite and filtered through a hot 10-cm. Buchner funnel, and the sand and Norite are washed with 75 cc. of hot... 

The catalyst is previously prepared in an apparatus for catalytic hydrogenation, in which are placed 0.5 g. of palladous chloride, 3.0 g. of Norite, and 20 ml. of distilled water. The bottle is swept out with hydrogen and then shaken with hydrogen for 2-3 hours at 2-3 atmospheres (40 lb.) pressure. The palladium on carbon is collected on a Biichner funnel, washed with five 50-ml. portions of distilled water, then with five 50-ml. portions of 95% ethanol, and finally twice with ether. Upon drying, about 3 g. of the catalyst is obtained. It is stored in a vacuum desiccator over solid sodium hydroxide. If the reduction of the chloro-lepidine does not proceed normally, the used catalyst should be removed by suction filtration and a fresh 3-g. portion of catalyst added. Failure of the reduction step is usually due to an inactive catalyst or to impurities in the acetic acid or chlorolepidine. The palladium catalysts, prepared as described elsewhere in this volume, are presumably also satisfactory for the reduction of 2-chlorolepidine (p. 77). 

Charcoal is generally satisfactorily activated by heating gently to red heat in a crucible or quartz beaker in a muffle furnace, finally allowing to cool under an inert atmosphere in a desiccator. Good commercial activated charcoal is made from wood, e.g. Norit (from Birch wood), Darco and Nuchar. If the cost is important then the cheaper animal charcoal (bone charcoal) can be used. However, this charcoal contains calcium phosphate and other calcium salts and cannot be used with acidic materials. In this case the charcoal is boiled with dilute hydrochloric acid (1 1 by volume) for 2-3h, diluted with distilled water and filtered through a fine grade paper on a Buchner flask, washed with distilled water until the filtrate is almost neutral, and dried first in air then in a vacuum, and activated as above. To improve the porosity, charcoal columns are usually prepared in admixture with diatomaceous earth. 

Pd-C (10% Pd) (Procedure D by Mozingo).178180 A solution of 8.33 g (0.0472 mol) of palladium chloride in 5.5 ml (-0.066 mol) of concentrated hydrochloric acid and 40 ml of water is prepared by heating the mixture on a water bath. The resulting solution is poured into a solution of 135 g of sodium acetate trihydrate (0.99 mol) in 500 ml of water contained in a 1-liter reduction bottle. Then 45 g of Norit is added, and the mixture is hydrogenated until absorption ceases after 1-2 h. The catalyst is collected on a Buchner funnel and washed with 2 liters of water in five portions. The filter cake, after removal of most of water, is dried in air and then in a desiccator over calcium chloride. The catalyst (48-50 g) is stored, after being powdered, in a tightly closed bottle. 

El-Sayed and Bandosz used three activated carbon samples of different origin, namely BPL from Calgon and MVP from Norit, both prepared from bituminous coal, and BAX from Westvaco, made from wood, using chemical activation with phosphoric acid for the adsorption of acetaldelyde. These carbons were washed in a soxhlet apparatus to remove water-soluble impurities and then oxidized with nitric acid. The adsorption of acetaldehyde was determined by inverse gas chromatography at infinite dilution and finite concentration. The heats of acetaldehyde adsorption at... 

Synthesis. DL-Valine is synthesized in 42% over-all yield by the method of Marvel (553). DL-a-Bromoisovalerio acid (A) is prepared in 88% yield by refluxing a mixture of isovaleric acid, bromine and phosphorus trichloride. The crude product, (b.p., 110-125 C./15 mm.) is distilled in vacuo. A mixture of (A) and concentrated ammonium hydroxide is allowed to stand at room temperature for a week. Excess ammonia is removed by distilling the mixture, and the resulting solution is distilled in vacuo to a thin paste. The residual material is filtered, the precipitate is dissolved in water, the solution is decolorised with norite, the sus pension is filtered, and an equal volume of 95% ethanol is added to the hot filtrate. The crude valine is washed with absolute ethanol A second crop is obtained by working up the filtrates. This procedure is essentially the same as that described by Clark and Fittig (157), Schlebusch (682), Schmidt and Sachtleben (686), and Slimmer (731). 

The preparation of this tetrapeptide described by Hutchings et al. (303) involves essentially the following operations. The culture medium, after removal of the bacteria, is adjusted to pH 3.0. The peptide is adsorbed on norit A, and after being washed with ethanol, is eluted with hot (70° C.) ammoniacal ethanol. The eluate is adjusted to pH 8.0, 8S % ethanol is added followed by a saturated solution of barium chloride, and the solution is cooled at 0° C. The barium pteroyltriglutamate precipitates, and its methyl ester derivative is prepared from the precipitate. The ester is extracted by butanol, and the butanol solution evaporated to dryness. The residue is redissolved by hot methanol, and the ester precipitates on cooling. The preceding purification is repeated, and finally, a controlled hydrolysis liberates the free acid which crystallizes. 

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