Aniline, recovery

The purge and the higher boiling mixture are processed away from the plant, and the recovered aniline returned to the crude aniline storage tank. The aniline recovery efficiency in the purge unit is 87.5 per cent, and a continuous stream of high-purity aniline may be assumed. 

Into a 1-litre beaker, provided with a mechanical stirrer, place 36 - 8 g. (36 ml.) of aniline, 50 g. of sodium bicarbonate and 350 ml. of water cool to 12-15° by the addition of a little crushed ice. Stir the mixture, and introduce 85 g. of powdered, resublimed iodine in portions of 5-6 g, at intervals of 2-3 minutes so that all the iodine is added during 30 minutes. Continue stirring for 20-30 minutes, by which time the colour of the free iodine in the solution has practically disappeared and the reaction is complete. Filter the crude p-iodoaniline with suction on a Buchner funnel, drain as completely as possible, and dry it in the air. Save the filtrate for the recovery of the iodine (1). Place the crude product in a 750 ml. round-bottomed flask fitted with a reflux double surface condenser add 325 ml. of light petroleum, b.p. 60-80°, and heat in a water bath maintained at 75-80°. Shake the flask frequently and after about 15 minutes, slowly decant the clear hot solution into a beaker set in a freezing mixture of ice and salt, and stir constantly. The p-iodoaniline crystallises almost immediately in almost colourless needles filter and dry the crystals in the air. Return the filtrate to the flask for use in a second extraction as before (2). The yield of p-iodoaniline, m.p. 62-63°, is 60 g. 

Based on tests with laboratory animals, aniline may cause cancer. The National Cancer Institute (NCI) and the Chemical Industry Institute of Toxicology (CUT) conducted lifetime rodent feeding studies, and both studies found tumors of the spleen at high dosage (100 —300 mg/kg pet day of aniline chloride). CUT found no tumors at the 10—30 mg/kg per day feeding rates. The latter value is equivalent to a human 8-h inhalation level of 17—50 ppm aniline vapor. In a short term (10-d) inhalation toxicity test by Du Pont, a no-effect level of 17 ppm aniline vapor was found for rats. At high levels (47—87 ppm), there were blood-related effects which were largely reversible within a 13-d recovery period (70). 

Recovery as liquid sulfur dioxide (absorption of clean dry off-gas in water or chemical absorbtion by ammonium bisulfite or dimethyl aniline),... 

In the manufacture of aniline from nitrobenzene the reactor products are condensed and separated into an aqueous and organic phases in a decanter. The organic phase is fed to a striping column to recover the aniline. Aniline and water form an azeotrope, composition 0.96 mol fraction aniline. For the feed composition given below, make a mass balance round the column and determine the stream compositions and flow-rates. Take as the basis for the balance 100 kg/h feed and a 99.9 percentage recovery of the aniline in the overhead product. Assume that the nitrobenzene leaves with the water stream from the base of the column. 

Hydrogenation of the nitrobenzene Separation of the reactor products by condensation Recovery of crude aniline by distillation Purification of the crude nitrobenzene Recovery of aniline from waste water streams... 

Human toxicity data are limited to secondary citations. Because these citations provided no experimental details, they cannot be considered reliable. Deaths have occurred from aniline ingestion and skin absorption, but doses were unknown. Reviews of the older literature indicate that a concentration of 5 ppm was considered safe for daily exposures, concentrations of 7 to 53 ppm produced slight symptoms after several hours, a concentration of 40 to 53 ppm was tolerated for 6 h without distinct symptoms, a concentration of 130 ppm may be tolerated for 0.5 to 1 h without immediate or late sequalae, and 100 to 160 ppm was the maximum concentration that could be inhaled for 1 h without serious disturbance. In studies of accidents with unknown exposure concentrations, methemoglobin levels of up to 72% were measured. Recoveries occurred with a minimum of medical intervention following cessation of exposure. 

In rats exposed at concentrations of 30 or 50 ppm for 8 h for up to 5 d, methemoglobin levels returned to control values after overnight recovery (10 ppm was identified by the authors as a no-effect level), whereas in the groups exposed at 150 ppm for 8 h or 50 or 150 ppm for 12 h for a maximum of 4 d, methemoglobin levels increased with increasing days of exposure. Hematocrit levels, measured 1 w after the start of exposure, were reduced at concentrations of >30 ppm. Signs of aniline intoxication either did not occur or were not reported. 

A comparison of active (using pumps) and passive (relying on diffusion) sampling techniques for the determination of nitrobenzene, benzene and aniline in air was mentioned in Section IV.A77. Several LLE methods for nitroaromatic compounds dissolved in water were evaluated. High recoveries were achieved with discontinuous or continuous extraction with dichloromethane, adsorption on a 1 1 1 mixture of Amberlite XAD-2, -4 and -8 resins and elution with dichloromethane445. 

Polymers and resins Water purification, including removal of phenol, chlorophenols, ketones, alcohols, aromatics, aniline, indene, polynuclear aromatics, nitro- and chlor-aromatics, PCB, pesticides, antibiotics, detergents, emulsifiers, wetting agents, kraftmill effluents, dyestuffs recovery and purification of steroids, amino acids and polypeptides separation of fatty adds from water and toluene separation of aromatics from ahphatics separation of hydroquinone from monomers recovery of proteins and enzymes removal of colours from symps ... 

This technique of MEUF has also been successfully employed for the recovery of thuringiensin [258], removal of cresols [262], extraction of chromate anion [257], removal of dissolved organic pollutants [256], removal of -alcohols [263],preconcentration and removal of iron [260], and preconcentration of aniline derivatives [261].Kandori and Schechter [264] have given a detailed account of selecting surfactants for MEUF. The design characteristics of micellar enhanced utrafilters and cross-flow ultrafiltration of micellar surfactant solutions have been described by Markets et al. [265]. 

CH3(CH3N=)CCH2COCH3 + (CH3(CH2)3NH2. A solution of the ligand (0.05 mole) in 10 ml. of n-butylamine was refluxed for one-half hour and distilled under reduced pressure (2 mm.). The product distilled at 77-80° at 2 mm., as did the pure ligand (recovery =95%). Similarly, only starting material was obtained (95% recovery) when aniline was used instead of n-butylamine. 

Liquid-liquid partitioning cleanup is generally carried out at alkaline conditions using ethyl acetate (481, 484), ethyl acetate/tert.-butanol mixture (482), diethyl ether (478), or tert.-butylmethyl ether/n-butanol (485) as extraction solvents. The organic extracts are then either concentrated to dryness (482), or repartitioned with dilute acid to facilitate back-extraction of the analytes into the acidic solution. A literature survey shows that liquid-liquid partitioning cleanup resulted in good recoveries of substituted anilines such as clenbuterol (478, 481, 484), but it was less effective for more polar compounds such as salbutamol (482). 

In a 3-I. beaker are placed no g. (1.2 moles) of aniline, 150 g. (1.76 moles) of sodium bicarbonate and 1 1. of water, and the mixture is cooled to 12-15° by the addition of a small amount of ice. The beaker is then fitted with ail efficient mechanical stirrer. The blade of a large porcelain spatula should be inserted into the liquid to overcome the rotary motion and thus obtain better mixing. The stirrer is started and 254 g. (1 mole) of powdered iodine is added in 15-20 g. portions at intervals of two to three minutes so that all the iodine is introduced during the course of one-half hour. Stirring is continued for twenty to thirty minutes. By this time the reaction is complete, and the color of the free iodine in the solution has practically disappeared. The crude -iodoaniline, which separates as a dark crystalline mass, is collected on a Biichner funnel, pressed as free from water as possible, and dried in the air. The filtrate may be saved for the recovery of iodine (Note 1). 

Thallous Azidodithiocarbonate A637-L Thallous-Thallic Azide A623-R Thermonuclear or Fusion Bomb. See under Atomic Bomb A499-L Thorium Dicarbide A82-R Tin Azide A624-L Titanium Carbide A82-R Titanous Chloride Method for Determination of Nitrobenzene in Aniline A415-R TNT Recovery from Scrap Amatol A161-L Toluidine. See under Aminotoluenes A265-R... 

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