A Short Note On Differential Extraction

When we say “extraction,” we are referring to the transference of a compound(s) from a solid or liquid into another solvent or phase. In the process of steeping a tea bag in hot water, those compounds responsible for the flavour and colour of the tea are released from its grounds and into the liquid. Decaffeinated coffee is produced by extracting the caffeine from coffee beans with the help of solvents or supercritical carbon dioxide, respectively. Among the flavours used by bakers in their creations are vanilla, almond, orange, lemon, and peppermint extracts, which are essences extracted from plant materials with the help of alcohol.

The process of liquid-liquid extraction is the most commonly used in the chemistry laboratory, and it takes place in a separatory funnel. A solution containing dissolved components is placed in the funnel, and an immiscible solvent is added, due to two layers that are shaken together to combine the two layers of solution. When two layers are used, it is most common for one to be aqueous and the other to be organic solvent. When components are moved from one layer to another, they are referred to as “extracted.” Drainage and separation of the two layers are made easier thanks to the funnel’s shape and design.

It is dependent on the relative solubility of compounds in different liquids that they move from one to another. The “like dissolves like” principle can be used as a quick guide to determine solubility, which means that nonpolar compounds should be easily extracted into nonpolar solvents (and vice versa). When it comes to tea, the compounds responsible for the flavour and colour must be polar in order to be easily extracted into hot water. A compound that is allowed to equilibrate between two liquids in a separatory funnel will almost always end up in the layer that is more soluble in that compound’s base liquid.

Methods of Purification

In order to determine the purity of an organic compound, one simple method is to either melt or boil it, as organic compounds are characterised by having extremely sharp melting and boiling points.

Purification is the process of removing any unwanted impurities that may be present in an organic compound. The following are the most common methods of purification

• Sublimation
• Crystallisation
• Distillation
• Differential Extraction
• Chromatography

Sublimation

Some solids can pass directly from the solid state to the vapour state without passing through the liquid state first. Sublimation is the term used to describe the purification technique that takes advantage of this property. It is useful in the separation of sublimable compounds from non-sublimable compounds, among other things.

Distillation

Because of the difference in boiling points between the two liquids, the underlying principle of distillation is that a mixture of liquids can be separated. The boiling point of a liquid is defined as the temperature at which the vapour pressure of the liquid equals the pressure of the surrounding atmosphere. This method is used to distinguish between volatile and non-volatile liquids.

Vacuum Distillation

Due to the fact that the boiling point is dependent on the atmospheric pressure, liquids will boil at a temperature lower than their boiling points if they are distilled in an atmosphere with lower pressure than the one in which they were distilled. This is accomplished through the use of a vacuum pump. Because the atmospheric pressure is reduced, the liquids boil at a faster rate, resulting in a more rapid distillation process throughout the process.

Differential Extraction

When dealing with immiscible liquids, which are liquids that do not mix together, this method is used. For example, oil and water are incompatible with one another.

The immiscible liquids are collected in a separating funnel and allowed to stand undisturbed for several hours. The liquids separate out according to their specific gravities after a period of time, with the heavier liquid at the bottom of the container. After that, they are gathered together.

The solubilities of various substances in a liquid can also be used to separate substances from one another. Consider the case of phenol extraction if it is necessary to extract phenol, it can be preferentially extracted by using NaOH solution as one of the liquids to be used.

Conclusion

In chemistry, differential extraction is defined as a technique that is used to separate any organic compound that is present in an aqueous solution from the rest of the solution.

The process of liquid-liquid extraction is the most commonly used in the chemistry laboratory, and it takes place in a separatory funnel. 

When two layers are used, it is most common for one to be aqueous and the other to be organic solvent. Purification is the process of removing any unwanted impurities that may be present in an organic compound.

Some solids can pass directly from the solid state to the vapour state without passing through the liquid state first. 

When dealing with immiscible liquids, which are liquids that do not mix together, a differential extraction method is used. For example, oil and water are incompatible with one another.