A Decanting funnel Or decanting pear is a glass funnel with a faucet or faucet in the bottom. It is a separation technique used for two liquids that do not dissolve with each other, called immiscible liquids.
Decantation funnels are standard laboratory pieces used to make extractions. They have a faucet on the bottom that is used to control how the two immiscible liquids that are in the jar are separated.
To use a decantation funnel, place the liquid mixture inside the container and place a container underneath. The liquid with the lowest density floats on the top.
When the key is open, the liquid with the highest density begins to float through the separating funnel into the container. Then, the key is closed just before the liquid with the lowest density begins to float through it.
The liquid with the lowest density remaining in the separating funnel can then be drained into another container to separate the two liquids.
Decantation funnels are commonly used in laboratory experiments, especially in the area of elements, mixtures and compounds. Decantation pears are used to facilitate separation based on solvents with the help of gravity.
Characteristics of the decanting funnel
A decanting funnel, also known as a decanting pear, is a laboratory piece made from glass used in liquid-liquid extractions to separate the components of a mixture into two immiscible solvent phases of different densities.
Typically, one of the phases will be aqueous, and the other will be an organic lipophilic solvent such as ether, MTBE, chloroform, ethyl acetate, or dichloromethane. All these solvents form a clear delineation between the two liquids.
The denser liquid, typically the aqueous phase unless the organic phase is halogenated, sinks and can be filtered from the less dense liquid remaining in the package through a valve.
Equipment Description
A decantation funnel is shaped like a cone with a hemispherical end. The conical shape increases the function of the equipment, as it allows a clear and easy separation of the two layers due to the small interface at the bottom.
The decanting pears have a stopper at the top and a key at the bottom. The decantation funnels used in laboratories are typically made of borosilicate glass and their plugs are made of glass or PTFE (Teflon).
The typical sizes are between 30 ml and 3 liters. In industrial chemistry they can be much larger and for much larger volumes centrifuges are used.
Inclined sides are designed to facilitate the identification of layers. The outlet controlled by the cap is designed to drain the liquid out of the settling funnel.
Above the funnel is a standard tapered clamp that fits in a tarnished glass or Teflon plug.
Applications
Decantation funnels or pears can be used for extractions of liquid into liquid. Two liquids that do not dissolve well in the other can be separated using this funnel based on different densities. For example, a mixture of oil and water may be separated using this technique.
The beaker of the separating funnel is directed over a vessel, and the mixture is served within the funnel; The mixture should be allowed to settle.
The two liquids in the mixture have different densities, causing the denser liquid, in this case water, to be placed in the base of the container.
The funnel faucet is then opened to allow water to pass into the vessel; The faucet is closed as soon as the oil reaches the peak, separating the two liquids.
Probably the greatest risk you have when using a settling pear is pressure buildup. The pressure builds up during mixing if a reaction with a gas occurs or if a physical change occurs.
This problem can be easily handled simply by opening the plug at the top of the funnel as it is mixed. This should be done with the funnel plug directed away from the body.
Theory on which the procedure is based
The funnels of decanting work under the concept that substances with similar molecules will dissolve in themselves; With different solutes preferably being soluble in certain solvents.
While a decantation funnel is being whipped, the two solvents are mixed and share a large surface area, allowing each solute to migrate to the solvent in which it is most soluble.
The solvents do not form a unified solution because they are immiscible. When the funnel is allowed to settle after being moved, the fluids form distinct physical layers, with the less dense liquid floating and the denser liquid sinking.
In this way, a mixture of solutes is physically separated into two separate solutions, each enriched in different solutes.
The bottom layer is filtered, then the upper layer can be retained in a separate funnel to be extracted with additional batches of solvent or it can be filtered in a separate vessel for other uses.
If it is desired to retain the lower layer in the settling funnel for future extractions, the two layers are removed separately, and then the lower back layer is returned to the settling pear.
Each separate solution can be withdrawn again with additional batches of solvent, used for other physical or chemical processes.
If the goal is to separate a soluble material from the mixture, the solution containing the desired product can sometimes simply be evaporated to leave the purified solute behind.
For this reason, it is a practical benefit to use volatile solvents to extract the desired material from the blend.
References
- Separatory Funnel. Retrieved from wikipedia.org
- What is a Separator Funnel? Retrieved from reference.com
- Elements compounds and mixtures. Recovered from gcsescience.com
- What is a Separator Funnel? (2016). Recovered from quora.com.