Are Esters Soluble in Water?

Small esters are soluble in water. However, as the length of the carbon chain increases, their solubility decreases. The solubility of esters is possible because the hydrogen atoms in water molecules are able to hydrogen bond with the oxygen atoms.

Solubility in water requires a substance or molecule to be hydrophilic. To understand this, it's important to know that water molecules are highly polar. This means that the oxygen atom has a slight negative charge while the hydrogen atoms have slight positive charges. Substances that are soluble in water are either polar - like water - or have parts that are polar. Although the hydrogen atoms in esters are bound to carbon atoms and have neutral charges, the oxygen atoms are often strongly polar.