Liquid amine residues

The procedure for the pn iodide (No, 108 d) is employed, using 26.2g of amine and 50ml of water. A heavy pink precipitate of cobalt (II) salt forms from the initial mixing, but most of this disappears after 3-4 hours of oxidation with air. The liquid and residual solid are evaporated on the steam hath to about 60ml and then suction-filtered to remove undecomposed [Codprh] I2. On further evaporation, a heavy skin begins to form persistently on the surface of the solution the cooled sirupy mass is poured into 500ml of... 

A suspension of sodium amide in 500 ml of anhydrous liquid artmonia was prepared from 18 g of sodium (see Chapter II, Exp. 11). To the suspension was added in 10 min with swirling a mixture of 0.30 mol of 1-chloro-l-ethynylcyclohexane (see VIII-2, Exp. 27) and 50 ml of diethyl ether. The reaction was very vigorous and a thick suspension was formed. The greater part of the ammonia was evaporated by placing the flask in a water bath at 50°C. After addition of 500 ml of ice-water the product was extracted three times with diethyl ether. The ethereal extracts were dried over anhydrous KjCOj and subsequently concentrated in a water-pum vacuum. Distillation of the residue afforded the amine, b.p. 54°C/15 mmHg, n 1.4345, in 87% yield. 

Liquid mixtures of methanol and hydrochloric acid slowly yield methyl chloride even at 0°C (20,21), The typical process is carried out by contacting the alcohol with hydrochloric acid at 70 to 160°C and 0.1—1 MPa (15—150 psig) in the presence of a catalyst such as zinc chloride, quaternary amines (18,19,22), or with no catalyst at aH (23,24). TypicaHy 0.5 to 3% of the methanol is converted to dimethyl ether. Product methyl chloride is taken out of the reactor as a vapor and is cooled to condense as much of the water vapor and HCl as possible. Dimethyl ether and the residual water is then removed and the finished methyl chloride is condensed. 

After standing about three hours, the diphenylamine hydrochloride is filtered and washed with benzene (Note 10). The benzene is distilled from the filtrate (Note n) and the residual triphenylamine is transferred to a 500-cc. modified Claisen flask (Org. Syn. 1, 40) and distilled under reduced pressure. The first fraction consists of some benzene, then the temperature rises rapidly and a few cubic centimeters of deeply colored distillate comes over just before the amine fraction, which is collected at i95-205°/io-i2 mm. The distillate is a yellow liquid which soon solidifies to a light yellow solid. The side arm of the distilling flask should be of rather large bore (about 10 mm.) to prevent clogging by the amine which solidifies. The crude product weighs 220-235 g. and melts at 120-124°. 

Smoking. The effects of smoking on the formation of N-nitros-amines in bacon has been investigated recently by Bharucha et al. ( ). They reported that unsmoked bacon samples generally tended to contain more N-nitrosamines, presumably because of their higher nitrite content at the time of frying. Sink and Hsu (55) showed a lowering of residual nitrite in a liquid smoke dip process for frankfurters when the pH also was lowered. The effects of smoke seem to be a combination of pH decrease and direct C-nitrosation of phenolic compounds to lower the residual nitrite in the product (56). This is an area which requires further study since certain C-nitrosophenols have been shown to catalytically transnitrosate amines in model systems (57). 

The lustrous black crystals of trirhenium nonabromide are not rapidly degraded on exposure to the atmosphere the crystals can be stored over desiccants for months without evidence of decomposition. The bromide dissolves fairly slowly and sparingly in ether and acetone. In methanol, the bromide gives yellow-orange solutions, but it is solvolyzed within minutes. Similarly, the bromide dissolves in water at room temperature to yield a violet solution which darkens rapidly, yielding a black precipitate, presumably the hydrated dioxide.9 Contrary to published work,10 the bromide does dissolve in ammonia with solvolysis, as is evidenced by lines attributable to ammonium bromide in x-ray diffraction data of the solid residue recovered from liquid ammonia solutions.11 Trirhenium nonabromide reacts with Lewis bases such as phosphines and amines to form a series of complexes of the type (base) 3Re3Br9.6... 

B. A -Butenolide. In a 500-ml. three-necked flask fitted with a mechanical stirrer, a reflux condenser, and a 250-ml. dropping funnel containing a solution of 61 g. (84.5 ml., 0.6 mole) of triethylamine in 70 ml. of dry diethyl ether, a solution of 83 g. (0.5 mole) of a-bromo-Y-butyrolactone and 200 ml. of dry diethyl ether is heated to reflux, with stirring. The amine solution is added, slowly, during 5 hours and the stirring under reflux continued for an additional 24 hours. The brown precipitate (40 g.) is removed by filtration. Most of the solvent is removed from the filtrate by evaporation, and the additional precipitate (8 g.) is removed. This precipitate is predominantly triethylamine hydrobromide. The liquid residue is distilled under reduced pressure and the -butenolide is collected at 107-109° (24 mm.) ... 

C. Crotyl diazoacetate. A solution of 10.0 g. (0.038 mole) of the />-toluenesulfonylhydrazone of glyoxylic acid chloride in 100 ml. of methylene chloride is cooled in an ice bath. Crotyl alcohol (2.80 g. or 0.038 mole) (Note 7) is added to this cold solution, and then a solution of 7.80 g. (0.077 mole) of redistilled triethyl-amine (b.p. 88.5-90.5°) in 25 ml. of methylene chloride is added to the cold reaction mixture dropwise and with stirring over a 20-minute period. During the addition a yellow color develops in the reaction mixture and some solid separates near the end of the addition period. The resulting mixture is stirred at 0° for 1 hour and then the solvent is removed at 25° under reduced pressure with a rotary evaporator. A solution of the residual dark orange liquid in approximately 200 ml. of benzene is thoroughly mixed with 100 g. of Florisil (Note 8) and then filtered. The residual Florisil, which has adsorbed the bulk of the dark colored by-products, is washed with two or three additional portions of benzene of such size that the total volume of the combined benzene filtrates is 400-500 ml. This yellow benzene solution of the diazoester is concentrated under reduced pressure at 25° with a rotary evaporator, and the residual yellow liquid is distilled under reduced pressure. (Caution This distillation should be conducted in a hood behind a safety shield) (Note 9). The diazo ester is collected as 2.20-2.94 g. (42-55%) of yellow liquid, b.p. 30-33° (0.15 mm.), n T) 1.4853 - 1.4856 (Note 10). 

A mixture of the pure (—)-amine salt (17.9-19.1 g.) and 90 ml. of water is treated with 15 ml. of aqueous 50% sodium hydroxide and the resulting mixture is extracted with four 75-ml. portions of ether. After the combined ether extracts have been washed with 50 ml. of saturated aqueous sodium chloride and dried over magnesium sulfate, the bulk of the ether is distilled from the mixture through a 30-cm. Vigreux column and the residual liciuid is distilled under reduced pressure. The (—)-amine is collected as 6.9-7.2 g. (55-58 () of colorless liquid, b.p. 94 95° (28 mm.), 1.5241-1.5244, —39.4° (neat) (Notes 4, 5). 

Ionic liquids have been used for the selenium- or palladium-catalyzed carbonylation of primary amines to form carbamates or ureas.After completion of the carbonylation, addition of water induced the precipitation of desired products, which were isolated by fdtration and separated from the ionic liquid, containing the catalytic species. Then, the catalyst could be reused after removal of residual methanol and water by distillation. Although the conversion of the reaction slightly decreased after the second run, the catalytic activity was considerably improved (from 70% to 99 %) by the addition of a small amount of the fresh catalyst. " ... 

In liquid chromatographic methods, reversed-phase columns are usually employed due to hydrophobic interaction of the amphenicols molecules witli the Cs or Ci8 stationary phases. Ion-pairing liquid chromatography has been also described for the separation of florfenicol and florfenicol amine (62) or chloramphenicol and deacetylchloramphenicol residues (46) using heptanesulfonate or octylsulfate-pairing ions, respectively. 

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