Extraction - Scale up calculations

Solvent extraction is a method used to separate compounds based on their relative solubilities in two immiscible liquids. It's commonly used in various industries including chemical, pharmaceutical, food processing, and environmental remediation.

How it works:

Selection of Solvents: Two immiscible solvents are chosen, typically one organic (e.g., chloroform, hexane) and one aqueous (e.g., water). The choice of solvents depends on the compounds to be extracted and their solubility properties.

Mixing: The two immiscible solvents are mixed together with the substance or mixture to be separated. This forms two phases: the organic phase and the aqueous phase.

Partitioning: The target compound(s) distribute themselves between the two phases according to their solubility in each solvent. Each compound will have a different partition coefficient, which determines its distribution between the two phases.

Separation: After allowing sufficient time for the phases to equilibrate, they are separated. This can be done using a separating funnel or other techniques.

Recovery: The compound(s) of interest are then recovered from one of the phases. This is often achieved by evaporating off the solvent, leaving behind the desired compound.


Key types:

Liquid-Liquid Extraction: This is the most common type, where two immiscible liquids are used to extract a solute from one phase to the other. It's widely used in chemical and pharmaceutical industries for purification and isolation of compounds.

Solid-Liquid Extraction (Leaching /Purification): This type is commonly known as leaching, where solid material slurry is prepared at higher temp as per suitability and impurities present solid material get leached into solvent. In pharmaceutical industry, this is called as purification.

Supercritical Fluid Extraction: Supercritical fluids, such as carbon dioxide, are used as solvents to extract compounds from solid or liquid samples. SFE offers advantages such as selectivity, mild operating conditions, and ease of solvent removal.

Countercurrent Extraction: This technique involves continuously extracting solute from one phase to another while simultaneously extracting solvent from the other phase. It's used for continuous separation and purification processes.