Aniline boiling point

Physical properties, taken as those of aniline Boiling point at 1.2 bar 190°C Molecular weight 93.13 Tc 699 K... 

Most students will be familiar with simple distillation from their practical inorganic chemistry. Other students should determine the boiling-point of acetone (56°), using a water-bath and water-condenser, or of benzene (81 ), using a sand-bath and water-condenser, and finally of either aniline (184 ) or nitrobenzene (210 ), using for both these liquids a sand-bath and air-condenser. 

The following liquids may be used (boiling points are given in parentheses) — chlorobenzene (132-3°) bromobenzene (155°) p cymene (176°) o-dichloro-benzene (180°) aniline (184°) methyl benzoate (200°) teti-alin (207°) ethyl benzoate (212°) 1 2 4-trichlorobenzene (213°) iaopropyl benzoate (218°) methyl salicylate (223°) n-propyl benzoate (231°) diethyleneglycol (244°) n-butyl benzoate (250°) diphenyl (255°) diphenyl ether (259°) dimethyl phth ate (282°) diethyl phthalate (296°) diphenylamine (302°) benzophenone (305)° benzyl benzoate (316°). 

Repeat the boiling point determination with the following pure liquids (a) carbon tetrachloride, A.R. (77°) (6) ethylene dibromide (132°) or chlorobenzene (132°) (c) aniline, A.R. (184-6°) and (d) nitrobenzene, A.R. (211°). An air condenser should be used for (c) and (d). Correct the observed boiling points for any appreciable deviation from the normal pressure of 760 mm. Compare the observed boiling points with the values given in parentheses and construct a calibration curve for the thermometer. Compare the latter with the curve obtained from melting point determinations (Section 111,1). 

Atophan. In a 1 litre round-bottomed flask, equipped with a reflux condenser, place 25 g. (24 ml.) of purified benzaldehyde (Section IV,115), 22 g. of freshly-distilled P3 ruvic acid and 200 ml. of absolute ethyl alcohol. Heat the mixture to tlie boiling point on a water bath and add slowly, with frequent shaking, a solution of 23 g. (22 -5 ml.) of pure aniline in 100 ml. of absolute ethyl alcohol. The addition usually occupies about 1 hour. Reflux the mixture on a water bath for 3 hours, and allow to stand overnight. Filter off the crude atophan (1) at the pump and wash the crystals with a little ether. Recrystallise from ethyl alcohol (about 20 ml. per gram). The yield of pure 2-phenvlquinoUne-4-carboxvUc acid, m.p. 210°, is 30 g. 

Determination of boiling points. Distillation method (Fig. II, 12, 1) for carbon tetrachloride (25 nil. distillation flask and small water condenser), and SiwoloboflF s method (Fig. II, 12, 2) for carbon tetrachloride, aniline and nitrobenzene. Calibration curve for thermometer. Determination of b.p. of unknown liquid. 

The simplest arylamme aniline is a liquid at room temperature and has a boiling point of 184°C Almost all other arylamines have higher boiling points Aniline is only... 

Most derivatives of aniline are not obtained from aniline itself, but ate prepared by hydrogenation of their nitroaromatic precursors. The exceptions, for example, /V-a1ky1ani1ines, /V-ary1ani1ines, sulfonated anilines, or the A/-acyl derivatives, can be prepared from aniline and have been discussed. Nitroanilines are usually prepared by ammonolysis of the corresponding chloronitroben2ene. Special isolation methods may be requited for some derivatives if the boiling points are close and separation by distillation is not feasible. Table 6 Hsts some of the derivatives of aniline that are produced commercially. 

Although less common, azeotropic mixtures are known which have higher boiling points than their components. These include water with most of the mineral acids (hydrofluoric, hydrochloric, hydrobromic, perchloric, nitric and sulfuric) and formic acid. Other examples are acetic acid-pyridine, acetone-chloroform, aniline-phenol, and chloroform-methyl acetate. 

Observable Characteristics - Physical State (as normally shipped) Liquid Color. Clear to light yellow turns yellow, brown or deep red on exposure to air and light Odor Aromatic, aniline-like. Physical and Chemical Properties - Physical State at 15 X and 1 atm. Liquid Molecular Weight 107.2 Boiling Point at 1 atm. 392, 200, 473 Freezing Point -11, -24, 249 Critical Temperature 790, 421, 694 Critical Pressure 544, 37.0, 3.75 Specific Gravity 0.998 at 20 °C (liquid) Vapor (Gas) Density Not pertinent Ratio of Specific Heats of Vapor (Gas) Not pertinent Latent Heat of Vaporization 179.1, 99.5,4.16 Heat of Combustion -16,180, -8,990, -376 Heat cf Decomposition Not pertinent. 

If substances of higher boiling-point have to be vaporised, the water in the outer jacket is replaced by other liquids of correspondingly higher boiling-point, such as xylene, b.p. 140°, aniline, b.p. 182°, ethyl benzoate, b.p. 211°, amyl benzoate, b.p. abo", diphenylamine, b.p. 310", c. A Lothar Meyer aii-bath... 

It is best prepared, however, by converting the alcohol, borneol, into bomyl chloride. The bornyl chloride is carefully dried and then gently warmed with an equal weight of aniline. The mixture is then heated to the boiling-point of aniline when the reaction, which is suddenly violent, 18 quickly completed. The reaction mass is neutralised by hydrochloric acid and distilled over in a current of steam. Gamphene is rapidly condensed and solidifies to a crystalline mass. 

Ketene (4, 39) It has been found that the formation of acetanilide from ketene and aniline takes place more satisfactorily if the ketene is passed directly into excess aniline without any dry ether present The excess aniline may then be removed by vacuum distillation until the temperature of the vapors is io-is° higher than the boiling point of aniline An alternative plan is to remove excess aniline by dilute hydrochloric acid, to filter the acetanilide and to wash with water. 

Make a rough estimate of the viscosity of 2-butanol and aniline at their boiling points, using the modified Arrhenius equation. Compare your values with those given using the equation for viscosity in Appendix C. 

Aniline is a liquid with a boiling point of 364°F. Its TLV is 2 ppm. It is absorbed through the skin. 

Experiment.—Anilinoquinone.1 Dissolve 4 g. of quinone in 400 c.c. of water. Cool the solution and add 1 -72 g. of aniline dissolved in 10 c.c. of 20 per cent acetic acid. Leave the mixture in the cold for three hours with frequent shaking, then collect the reddish-brown crystalline precipitate at the pump, dry it in vacuo, and free it from the monoanilino-compound by repeated careful boiling with petrol ether (boiling point 80°-90°). From the petrol ether this compound separates on cooling in the form of small golden-brown needles. Melting point 119°. The insoluble portion consists of dianilinoquinone. 

Improvement in the accuracy of the linear yield equations might be obtained by using more independent variables in the prediction process. For instance, the use of aniline point and volumetric average boiling point (VABP) might lead to better accuracy. Unfortunately, the published data do not include these two variables. 

Pearce et al, (21) pointed out that changes in boiling point, number of carbon atoms, aniline point, refractive index, density, and gravity within a series of fractions of an oil are proportional to the change in molecular weight. The relationships observed in plotting correlations of efficiency to these factors would be similar to those illustrated by correlar tion with molecular weight. 

Gravity, API Specific gravi iFlash pomt, Tm, F. eooeity, S.U.K at 100 1 Aniline point, F. Unaulfonated residue, % Acid number Distillation, ASTM, F. Initial boiling point 10%... 

---