Azeotrooppisuuden

Azeotrooppisuuden, in Finnish, refers to the property of a liquid mixture where the components coexist in the vapor phase in the same composition as in the liquid phase, creating a constant boiling point. This phenomenon occurs when the vapor pressure of the mixture behaves in a way that the mixture boils at a single temperature, despite the presence of more than one component. The resulting mixture is called an azeotrope and can be either type I (minimum boiling) or type II (maximum boiling) depending on whether the azeotropic point is below or above the temperatures of the pure components.

The concept is crucial in chemical engineering and distillation, as azeotropes limit the efficiency of separation by simple distillation. When a mixture approaches an azeotropic composition, further distillation does not increase the purity of the desired component. To overcome this, methods such as azeotropic distillation, extractive distillation, or the use of entrainers are employed. A common example is the ethanol–water system, forming a minimum-boiling azeotrope at about 95.6 % ethanol which cannot be isolated by ordinary distillation alone.

Azeotrooppisuuden also has practical importance in industries like pharmaceuticals, petrochemicals, and fuels, where precise control over separation processes is essential. Understanding the thermodynamic behavior of azeotropes allows engineers to design more efficient thermionic systems and to predict how mixtures will behave under varying temperature and pressure conditions.