Azeotropic Distillation

Azeotropic Distillation is one of the main type of distillation to do distillation of same boiling mixture. If boiling point difference between mixture of chemicals is greater than 50 degree Celsius then we can do simple distillation. If boiling point difference between two chemicals is very close then we can do fractional distillation.

If you want to study distillation in deep , read my article on it.

Distillation is very important for chemical engineers. Almost all industry use this separation process.

Definition of Azeotropic distillation

“Azeotropic distillation can be defined as distillation process of Azeotropic mixture (constant boiling mixture) by adding third components to brake the Azeotrope”.

Another definition “Azeotrpic distillation is process of separation of (constant boiling mixture) by adding third components (entrainer) and form new azeotrops which is mixture of immersible liquids “.

Azeotropic mixture

Before to study about azeotropic distillation we need to know exact meaning of azeotrpic mixture .
We need ask “what is Azeotropes ? ” ,”what is azeotropic distillation ? “.
Azeotrpic mixture is constant boiling mixture , after heating of this type mixture you will gate vapor composition is same as liquid phase . In simple words azeotropic mixture is that mixture which has same concentration in his liquid or vapor phase.
Some common examples of Azeotrpic mixtures are as follows .
(Azeotropic Distillation – Definition and Detailed Explanation )

1) Methanol – water Azeotropic mixture
2) Phenol-Toluene
3) Ethanol- Water

There are two types of Azeotropes

Minimum boiling Azeotropes
Maximum boiling Azeotropes

Minimum boiling Azeotropes

This types of Azeotropes has lower boiling point than its components. Example,let us considered , a azeotrpic mixture of component “A” and component “B”. Component “A” boil at 80 degree and component “B” boiling point is 112 degree . After heating of its mixture ( A & B mixture ) ,boiling start at 79 degree . So this type Azeotrope is called as “minimum boiling Azeotropes“.Separation if water and IBA is one of the example of minimum boiling Azeotropes. Second example is water dehydration .
Minimum boiling Azeotropes also called as Negative Azeotropes.

Maximum boiling Azeotropes

This types of Azeotropes has higher boiling point than its components. Example,let us considered , a azeotrpic mixture of component “A” and component “B”. Component “A” boil at 80 degree and component “B” boiling point is 112 degree . After heating of its mixture ( A & B mixture ) ,boiling start at 114 degree . So this type Azeotrope is called as “maximum boiling Azeotropes“.
Maximum boiling Azeotropes also called as positive Azeotropes.

Hope from above explanation is sufficient for you to get idea about Azeotropic mixture with examples. Now we will focus on Azeotropic distillation . “Fractional distillation“

Another Types of Azeotropes are as follows.

Homogeneous Azeotropes
Heterogeneous Azeotropes

Homogeneous Azeotropes

Homogeneous Azeotropes are mixture of those components which are completely miscible not partially with a concentration limits.

Homogeneous Azeotropes

Heterogeneous Azeotropes are mixture of those components which are not completely miscible or miscible partially with a concentration limits.

Example of Azeotropic mixture and distillation of Azeotropes is, Azeotropes of phenol-water .
Please refer following diagram for the distillation of phenol water Azeotropes.

Fig- Azeotropic distillation of Phenol-water

Boiling point of phenol is 180 and boiling point of water is 100 degree. When we start simple distillation of this mixture we will get vapor of both phenol and water . so in this way can not separate the phenol-water mixture by simple distillation . To brake the phenol-water Azeotropes we need to add toluene solvent on it . Toluene is miscible with phenol not with water.After heating this mixture we will get vapors of toluene and water . This vapors get condensed in condenser. In decanter toluene will get return to reactor and water will separate out.Hope from above example you will get idea about , Azeotropes ,Azeotropic mixture ,minimum boiling Azeotropes,Maximum boiling Azeotropes ,homogeneous Azeotropes , heterogeneous Azeotropes.Difference between azeotropic distillation and extractive distillation

The main difference in azeotropic and extractive distillation is , in extractive distillation we will get add third solvent at bottom of the mixture . In Azeotropic distillation we will get third solvent at the top or in distillation mixture .Second main difference between azeotropic and extractive distillation is , in azeotropic distillation old azeotrope brake and new azeotropes form . While in Extractive distillation only old azeotropes brake ,in this method new azeotrope will not form.

what is advantages and dis-advantages of azeotropic distillation ? The main advantage is we will get desired separation of mixture . And main dis-advantage is we get west of energy also some solvent losses will increases in this method.Home from above explanation you get clarification for Azeotropic Distillation-Advantage,Disadvantages.If you still have any confusion for this you can comment bellow .I will try my best to give clarification to you.

People also ask

1. What is meant by azeotropic distillation?

Azeotropic distillation is a type of distillation process used to separate azeotropic mixtures, which are liquid mixtures that have a constant boiling point and composition. In these mixtures, the components have a unique ratio that evaporates and condenses together, resulting in a vapor with the same composition as the liquid. As a result, traditional distillation methods fail to effectively separate the components of an azeotropic mixture. Azeotropic distillation overcomes this limitation by using an additional entrainer or solvent that forms a separate azeotropic mixture with one of the components. The introduction of the entrainer alters the relative volatility of the components, allowing for successful separation during the distillation process.

2. What is azeotropic distillation application?

Azeotropic distillation is commonly used in various industries and laboratories for separating and purifying components that form azeotropic mixtures. Some common applications include:

Petroleum Refining: Azeotropic distillation is employed in refining processes to separate and purify specific hydrocarbons from crude oil.

Alcohol Production: In the production of high-purity ethanol, azeotropic distillation is used to remove water from the ethanol-water mixture.

– **Chemical Manufacturing:** Azeotropic distillation plays a crucial role in producing pure chemicals, where traditional distillation techniques would be ineffective.

Pharmaceuticals:-Separation and purification of certain pharmaceutical compounds are achieved using azeotropic distillation.

3. What is the difference between azeotropic and simple distillation?

The main difference between azeotropic distillation and simple distillation lies in the composition and behavior of the mixtures being separated:

Simple Distillation :- Simple distillation is used to separate components of a mixture that have significantly different boiling points. The process involves heating the mixture to its boiling point, collecting the vapor, and condensing it back into a liquid, resulting in the separation of the components based on their boiling point differences.

Azeotropic type of Distillation: Azeotropic kind of distillation is employed when the components of a mixture form an azeotrope, meaning they have a constant boiling point and composition. Traditional simple distillation fails to effectively separate such mixtures, but azeotropic distillation utilizes an entrainer or solvent to alter the relative volatility of the components and achieve successful separation.

4. What is an example of an azeotrope?

One well-known example of an azeotrope is the ethanol-water azeotrope. This mixture contains approximately 95.6% ethanol and 4.4% water by mass and has a constant boiling point of 78.2 degrees Celsius (172.8 degrees Fahrenheit) at atmospheric pressure. This means that no matter how much heat is applied and how long the distillation process runs, the resulting vapor will have the same composition as the liquid mixture. To obtain anhydrous (water-free) ethanol, azeotropic distillation with an entrainer like benzene or cyclohexane is used to break the azeotrope and achieve separation.

Conclusion

From above article we will understand what is azeotropes ? what article the difference types of azeotropes ? what is minimum boiling azeotropes ? what is maximum boiling azeotropes ? Also we clear that when azeotropic distillation is required .Azeotropes mixture is constant boiling mixture , when we heat it without following method of azeotropic distillation , this mixture is start to boil at same temperature so we can not separate .We get clear idea as following.