Acetone, boiling point

Cylinder acetylene entails variable percentage quantities of solvent (normally acetone, boiling point 133° F [56.2° C]). The amount of solvent present in the expelled gas is dependent upon the vapor pressure of the solvent, the conditions of the cylinder, and the conditions of withdrawal. The purities listed in Table 1 are given on a solvent-free basis. 

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. 

In view of the boiling points of acetone (57°) and isopropanol (82 ), the acetone can be steadily distilled off from the reaction-mixture, and the reduction ultimately becomes virtually complete. 

If the substance is found to be far too soluble in one solvent and much too insoluble in another solvent to allow of satisfactory recrystallisation, mixed solvents or solvent pairs may frequently be used with excellent results. The two solvents must, of course, be completely miscible. Recrystallisation from mixed solvents is carried out near the boiling point of the solvent. The compound is dissolved in the solvent in which it is very soluble, and the hot solvent, in which the substance is only sparingly soluble, is added cautiously until a slight turbidity is produced. The turbidity is then just cleared by the addition of a small quantity of the first solvent and the mixture is allowed to cool to room temperature crystals will separate. Pairs of liquids which may be used include alcohol and water alcohol and benzene benzene and petroleum ether acetone and petroleum ether glacial acetic acid and water. 

Selection of solvents. The choice of solvent will naturally depend in the first place upon the solubility relations of the substance. If this is already in solution, for example, as an extract, it is usually evaporated to dryness under reduced pressure and then dissolved in a suitable medium the solution must be dilute since crystallisation in the column must be avoided. The solvents generally employed possess boiling points between 40° and 85°. The most widely used medium is light petroleum (b.p. not above 80°) others are cycZohexane, carbon disulphide, benzene, chloroform, carbon tetrachloride, methylene chloride, ethyl acetate, ethyl alcohol, acetone, ether and acetic acid. 

Dissolve or suspend 0 - 5 g. of the acid in 5 ml. of water in a small conical flask, add a drop or two of phenolphthalein indicator, and then 4-5 per cent, sodium hydroxide solution until the acid is just neutrahsed. Add a few drops of very dilute hydrochloric acid so that the final solution is faintly acid (litmus).f Introduce 0-5 g. of p-bromophenacyl bromide (m.p. 109°) dissolved in 5 ml. of rectified (or methylated) spirit, and heat the mixture under reflux for 1 hour if the mixture is not homogeneous at the boiling point or a solid separates out, add just sufficient alcohol to produce homogeneity. [Di- and tri-basic acids require proportionately larger amounts of the reagent and longer refluxing periods.] Allow the solution to cool, filter the separated crystals at the pump, wash with a little alcohol and then with water. Recrystallise from dilute alcohol dissolve the solid in hot alcohol, add hot water until a turbidity just results, clear the latter with a few drops of alcohol, and allow to cool. Acetone may sometimes be employed for recrystallisation. 

A representative technical grade of methyl chloride contains not more than the following indicated quantities in ppm of impurities water, 100 acid, such as HCl, 10 methyl ether, 20 methanol, 50 acetone, 50 residue, 100. No free chlorine should be detectable. Traces of higher chlorides are generally present in methyl chloride produced by chlorination of methane. The boiling point should be between —24 and —23° C, and 5—95% should distill within a range of about 0.2°C. It should be clear, colorless, and free from visible impurities. 

Isopropyl Ether. Isopropyl ether is manufactured by the dehydration of isopropyl alcohol with sulfuric acid. It is obtained in large quantities as a by-product in the manufacture of isopropyl alcohol from propylene by the sulfuric acid process, very similar to the production of ethyl ether from ethylene. Isopropyl ether is of moderate importance as an industrial solvent, since its boiling point Hes between that of ethyl ether and acetone. Isopropyl ether very readily forms hazardous peroxides and hydroperoxides, much more so than other ethers. However, this tendency can be controlled with commercial antioxidant additives. Therefore, it is also being promoted as another possible ether to be used in gasoline (33). 

FIG. 13-12 Liq iiid boiling points and vapor condensation temperatures for maximum-boiling azeotrope mixtures of chloroform and acetone at 101.3 kPa (1 atm) total pressure. 

This example clearly shows good distribution because of a negative deviation from Raonlt s lawin the extract layer. The activity coefficient of acetone is less than 1.0 in the chloroform layer. However, there is another problem because acetone and chloroform reach a maximum-boiling-point azeotrope composition and cannot be separated completely by distillation at atmospheric pressure. 

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. 

Class IB liquids with flashpoints below 73°F and boiling points at or above 100°F. Examples of Class IB flammable liquids are benzene, gasoline, and acetone (NFPA Diamond 3). 

In a later version of the synthesis [9], the trifluoroethyl difluoromethyl ether IS made directly from tnlluoroethanol and chlorodifluoromethane (equation 2) and then chlorinated to give the final product. Again, the major problem is overchlorination, because all the hydrogens are readily replaced by chlorine. Separation of the overchlonnated by-products poses a special problem because of close boiling points. This problem can be solved by adding acetone to create a more easily separable azeotrope of acetone and isoflurane [10]. 

In order to shift the equilibrium of the reaction, the low boiling reaction product acetone is continuously removed from the reaction mixture by distillation. By keeping the reaction mixture at a temperature slightly above the boiling point of acetone, the reaction can then be driven to completion. 

Other Lewis-acidic alkoxides might also be employed however aluminum isopropoxide has the advantage to be sufficiently soluble in organic solvents, and acetone as oxidation product can be easily removed for its low boiling point. Recently lanthan isopropoxide has been used with success, and showed good catalytic activity. 

The alcohol and the excess of acetone are first distilled off and then an essential oil is obtained, which, after the first distilled portion (about 4 kg.) of specific gravity 0 88 has been removed, represents the stuff for producing ai-tificial oil of violets. It is an essential oil with a boiling-point of 155° to 175° at 12 mm. pressure (about 25 kg.). 

Alcohol and acetone may be detected by their low boiling-point and by the iodoform test. Oils containing alcohol form milky mixtures with water. It may be extracted by washing with water, when the refractive index of the washed oil is found to be distinctly higher than that of the original oil. 

Methyl ethyl ketone MEK (2-butanone) is a colorless liquid similar to acetone, but its boiling point is higher (79.5°C). The production of MEK from n-butenes is a liquid-phase oxidation process similar to that used to... 

What is the freezing point and normal boiling point of a solution made by adding 39 mL of acetone, C3HeO, to 225 mL of water The densities of acetone and water are 0.790 g/cm3 and 1.00 g/cm3, respectively. 

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