Benzene, removal

Hence one extraction with 100 ml. of benzene removes 3 0 g. (or 75 per cent.) of the n-butyric acid, whilst three extractions remove 3 5 g. (or 87-5 per cent.) of the total acid. This clearly shows the greater efficiency of extraction obtainable with several extractions when the total volume of solvent is the same. Moreover, the smaller the distribution coefficient between the organic solvent and the water, the larger the number of extractions that will be necessary. 

Furfuryl acetate. Reflux a mixture of 39 2 g. (34-8 ml.) of redistilled furfuryl alcohol, 48 g. of glacial acetic acid, 150 ml. of benzene and 20 g. of Zeo-Karb 225/H in a 500 ml. bolt-head flask, using the apparatus described under iaoPropyl Lactate. After 3 hours, when the rate of collection of water in the water separator is extremely slow, allow to cool, separate the resin by suction filtration, and wash it with three 15 ml. portions of benzene. Remove the benzene, etc., from the combined filtrate and washings under reduced pressure (water pump) and then collect the crude ester at 74-90°/10 mm. a small sohd residue remains in the flask. Redistil the crude ester from a Claisen flask with fractionating side arm pure furfuryl acetate passes over at 79-80°/17 mm. The yield is 14 -5 g. 

Data of Waste Stream for the Benzene Removal Example... 

Catalytic hydrogenation in acetic anhydride-benzene removes the aromatic benzyl ether and forms a monoacetate hydrogenation in ethyl acetate removes the aliphatic benzyl ether to give, after acetylation, the diacetate. Trisubstituted aDcenes can be retained during the hydrogenolysis of a phenolic benzyl ether. ... 

Carbon tetrachloride is dried over calcium chloride and distilled before use. Triphenylphosphine is dried by dissolving it in dry benzene, removing the solvent under vacuum, and storing over phosphorus pentoxide. Alcohols should also be dried before use. 

The variation of removal efficiencies of benzene according to the inlet loading rate and the liquid recirculation rate is shown in Fig. 3. As shown in the figure, the removal efficiency of benzene decreases with increasing the inlet loading rate and decreasing the liquid recirculation rate. At an inlet loading rate less than 40 g/m -hr, benzene removal efficiency shows a little variation as the liquid recirculation rate increases. However, the removal efficiency... 

Fig. 5 shows the effect of operating temperature on benzene removal efficiency. 

In the flask are placed 240 g. (2 moles) of acetophenone and 1 1. of glacial acetic acid. The thermometer is adjusted so that it extends considerably below the surface of the solution, and chlorine is admitted at such a rate that the temperature does not exceed 60° (Note 1). Chlorination is continued until an excess of the halogen has been absorbed. This requires about five hours completion of the reaction is indicated by the development of a yellow color. The reaction mixture is poured over 6 1. of crushed ice in a 2-gal. jar. The mixture is stirred several times (Note 2) and allowed to stand until the ice has melted. The dichloroacetophenone, which separates as a heavy lachrymatory oil, is removed. The yield is 340-370 g. (90-97 per cent of the theoretical amount). This product, containing only a few per cent of water and acetic acid, is pure enough for the preparation of mandelic acid. It may be purified by adding about 100 cc. of benzene, removing the... 

The benzene removes any residual alcohol which may interfere with the subsequent acylation.3 4 ... 

B. a,a-Dimethyl-p-phenethylamine. In a 3-1., three-necked, round-bottomed flask equipped with a reflux condenser and a sealed stirrer are placed 246 g. (1.39 moles) of N-formyl-a,a-dimethyl-d-phenethylamine and 2.11. of 20% sodium hydroxide solution. The mixture is heated under reflux with vigorous stirring for 2.5 hours or until a test portion of the oily layer dissolves completely in cold 5% hydrochloric acid. The reaction mixture is cooled, 750 ml. of benzene is added, the mixture is stirred, and the benzene layer is separated. The benzene solution is shaken with a saturated sodium chloride solution, the benzene removed... 

Reddy, K. R. and Jeffery, A. A., 1988, Systems Effects on Benzene Removal from Saturated Soils and Ground Water Using Air Sparging Journal of Environmental Engineering, March, 1998, Vol. 124, No. 3, pp. 288-299. 

Other studies reporting benzene degradation under anaerobic conditions are similarly difficult to interpret. For instance, Ghosh Sun (1992) observed a loss of l6mg/l benzene over a 44 day period in a bioreactor that did not exhibit a detectable lag period prior to the onset of benzene removal. We can only presume that the bioreactor was not methanogenic as the ambient pH was 5.2-5.5, but no exogenously supplied electron acceptor was available. In this study, the abiotic loss observed in a single control bottle accounted for 50% of the total mass of benzene. 

Owing to hydrolysis in alkaline or neutraj solutions, it is very difficult to free the acid from a slight odor of benzaldehyde if it is recrystallized from water, but a final washing with benzene removes this odor. 

The benzene solution is dried with 20 g. of calcium chloride and the benzene removed by distillation under diminished pressure on a water bath. The residue is poured into a mortar where it solidifies. The crystalline mass is then ground with small amounts of ether (200 cc. in all), filtered, and washed with ether (about roo cc.) until pure white. The yield of phthalimi-domalonic ester melting at 73-740 is rss-r62 g. From the ether filtrate after distilling the ether, there may be recovered a further amount by washing with a small amount of ether to remove the brown color. The total weight of ester obtained in the two crops is 180-190 g. (67-71 per cent of the theoretical amount),... 

After stirring has been continued for two hours longer, the crock is surrounded by hot water or steam and warmed to 50° without stirring. The mixture is then allowed to stand until cool, when the aqueous layer is drawn off by means of a siphon. The upper oily layer is transferred to a 12-I. flask and distilled in a current of steam until no more oil passes over about 10 1. of distillate is collected (Note 6). The water is drawn off and the benzene removed by distillation, by means of a 2-1. round-bottom flask and a fractionating column about 90 cm. long. When benzene no longer distils over, the distillation is continued in the same apparatus under reduced pressure, and the fraction that boils at 94-96°/20 mm. is collected. A small amount of dark-colored residue remains in the flask. The yield of almost colorless o-tolunitrile is 300-330 g. (64-70 per cent of the theoretical amount). 

Method II.—-10 gms. (1 mol.) of benzophenone are refluxed with 100 gms. (excess) of alcohol, and 10 gms. (excess) of sodium wire are gradually added through an addition tube (see p. 50) to the boiling liquid. When the solution of the sodium is complete, the liquid in the flask is cooled, saturated with carbon dioxide, poured into cold water and the whole extracted with benzene. The extract is dried for 24 hours over calcium chloride, the benzene removed on a water bath, and the residue distilled under reduced pressure, the fraction 174°—176° at 80 mms. being retained. 

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