2.11 Solubility of Organics

2.11.1 Aliphatic Hydrocarbons

Hydrocarbons do not mix well with water. The longer the hydrocarbon, the more dispersion and the lower the solubility.

Figure 2.23: Aqueous solubility of some aliphatic hydrocarbons at 25 °C.

Structures

Butane, C₄H₁₀

Pentane, C₅H₁₂

Hexane, C₆H₁₄

Heptane, C₇H₁₆

Octane, C₈H₁₈

Nonane, C₉H₂₀

2.11.2 Alcohols

Alcohols contain an –OH functional group and can increase the solubility of a compound.

Figure 2.24: Aqueous solubility of some alcohols at 25 °C.

Structures

1-Butanol, C₄H₉OH

1-Pentanol, C₅H₁₁OH

1-Hexanol, C₆H₁₃OH

1-Heptanol, C₇H₁₅OH

1-Octanol, C₈H₁₇OH

1-Nonanol, C₉H₁₉OH

2.11.3 Aromatic Compounds

Aromatic compounds contain one or more rings with delocalized pi electrons and are not very soluble in water.

Figure 2.25: Aqueous solubility of some aromatic compounds at 25 °C.

Structures

Benzene, C₆H₆

Naphthalene, C₁₀H₈

Anthracene, C₁₄H₁₀

Pyrene, C₁₆H₁₀

Benzo[a]pyrene, C₂₀H₁₂

2.11.4 Functionalized Aromatics

Modifying aromatic compounds by adding other atoms or functional groups to the aromatic ring can increase the solubility of the molecule depending on the functional group.

Figure 2.26: Aqueous solubility of some functionalized aromatics at 25 °C.

Structures

Benzene, C₆H₆

Toluene, C₇H₈

Phenol, C₆H₆O

Aniline, C₆H₅NH₂

Nitrobenzene, C₆H₅NO₂

Bromobenzene, C₆H₅Br