Cyclohexanol boiling point

Correction for boiling point, 59 Creatine, 132 -Cresol, 164 Cryoscopic method, 32 Crystallisation, 52 Cuprous chloride, 166 Cyclohexanol, 181... 

The reaction mixture is slowly heated using the apparatus shown. Cyclohexene has a lower boiling point (83°C) than cyclohexanol (160°C) and so will vaporise first and rise up through the apparatus. 

The resulting mixture is stirred for 4 hours at room temperature and then poured, while stirring slowly, into a mixture of 25 g of ammonium chloride, 50 ml of water and 50 g of ice. The layers are separated and the aqueous layer is extracted twice with 50 ml portions of ether. The organic layers are combined, dried with sodium sulfate and evaporated. The residue is distilled, and l-(m-methoxyphenyl)-2-dimethylaminomethyl-cyclohexanol-(l), boiling point at 0.6 mm Hg 138°C to 140°C, is obtained in a yield of 78.6% of theoretical. 

Handling the separation problem involves essentially the ternary mixture phenol/ cyclohexanone/cyclohexanol. As Table 5.10 indicates, phenol is the highest boiler (181.9°C), followed by cyclohexanol (160.8°C) and cyclohexanone (155.4°C). Phenol forms positive azeotropes with cyclohexanone and cyclohexanol, of similar composition (roughly 75% mol phenol) and very similar boiling points. 

Table 5.10 Boiling points for the mixture phenol/cyclohexanone/cyclohexanol [3, 5].

Figure 5.7 displays the RCM of the ternary mixture cyclohexanone/cyclohexa-nol/phenol at 0.1 bar. Note the existence of a distillation boundary that prevents recycling pure phenol, as well as the fact that the difference between the boiling points of azeotropes is only 1 °C. The RCM suggests that cyclohexanone will separate easily by distillation, while phenol will be recycled as an azeotrope, most probably with cyclohexanol. 

Dehydration of alcohols. A mixture of 0.5 mole of cyclohexanol, 0.5 mole of phthalic anhydride, and 2.5 g. of benzenesulfonic acid is heated gently at the boiling point for 30 min., and the distillate is saturated with sodium chloride. The... 

Transfer hydrogenation is another method widely used in ketone reduction. As a source of hydrogen, secondary alcohols like /PrOH are preferred, and the reaction is carried out in presence of KOH at the boiling point of the solvent. Reactions catalyzed with ruthenium complexes working at higher reaction temperatures were often performed in cyclohexanol or benzylalcohol, but, as a consequence of hydrogen transfer from the secondary alcohols produced, the reaction becomes reversible. 

Purpose. This experiment illustrates the separation of a 25-(xL mixture, consisting of heptanal and cyclohexanol, into the pure components. The volume of the mixture is approximately that of a single drop, and the materials boil within 7 °C of each other. This mixture would be difficult, if not impossible, to separate by the best distillation techniques available. The purity of the fractions collected from the gas chromatograph (GC) can be assessed by boiling points, refractive indexes, or infrared (IR) spectra. 

Rank each group of compounds in order of increasing boiling point, (a) Cyclohexane, cyclohexanol, chlorocyclohexane (b) 2,3-dimethyl-2-pentanol, 2-methyl-2-hexanol, 2-heptanol. 

Cis-2-[a-dimethylamino-m-(methoxymethoxy)benzyl] cyclohexanol (10 g) in ether was treated with a slight excess of isopropanolic hydrogen chloride. The gummy solid which crystallized on trituration with boiling ether-acetone was recrystallized first from ethanol-ether and finally from methanol-acetone to give the cis-2-(a-dimethylamino-m-hydroxybenzyl)cyclohexanol, hydrochloride, melting point 263-265°C [a]D25 = -15.3° (methanol). 

---