Purification of Organic Compounds- IV

Various topics in the CBSE class 11 link with the other main topics and affect their effects. Purification of organic compounds class 11 is one of the topics that influence the other topics of chemistry vastly. Thus understanding this is highly important. The notes from Unacademy for this topic cover all the topics and help understand the various methods used to purify organic compounds. The study includes the definition and importance of purification and the methods used in this process. Also, the detailed clarification of the methods provides a detaining overview in these notes. 

Importance:

The purification of organic compounds is crucial as it isolates unwanted compounds from natural sources. In nature, the organic compounds remain in a contaminated stage with a mixture of dirt, chemicals, sand, and many more. Also, the impurities of the compounds not only occur due to the extraction from nature but can also occur due to the chemical reactions performed in the laboratory. 

Due to this reason, it is essential to opt for the purification of organic compounds so that the manufacturing and extraction of the compounds perform in the best manner and the need of availing of the natural compound made at best.

Also, after performing the purification of organic compounds, the compounds went through the checking process and then are determined by the measuring of these compounds that helps to obtain the physical constants of the substances, including the boiling point, melting refractive index, and many more. Apart from several methods of purification of organic compounds, they are used along with the spectroscopic methods that help to understand the purity of the organic compound. 

Methods:

Several methods of purification of organic compounds are further discussed below to understand better. 

• Crystallization

The purification of organic compounds by crystallization is a process used to arrange the atoms/ molecules of a compound in a well-defined manner with three-dimensional lattices and minimize the whole energy of the system. Also, in this process, the atoms present in the organic compound bid together with the help of well-defined angles. 

However, the purification of organic compounds by crystallization is further divided into two processes that include:

• Simple Crystallization

This is the most common method of purification of organic compounds, where a suitable solvent is required that includes:

• The one where the impurities are either insoluble or dissolvable to the extent that they stay in the solution with the help of this process. 

• Another one is the dissolve of more of the substance occurring at higher temperatures rather than room temperature.

• The one that does not react chemically, in the crystallization process of a compound, and, 

• The one that is not highly inflammable. 
• Ether, chloroform, water, alcohol, acetone, carbon-tetrachloride, benzene, petroleum ether, and many more are the common solvent used to purify organic compounds by crystallization simply.
  

• Fractional Crystallization

Several repeated crystallization is performed in the fractional purification of organic compounds by crystallization. However, the mixture is dissolved in a solvent in the first step, where two compounds have different solubility. Also, when the hot saturated mixture is placed in the cool mixture, less soluble compounds come out, whereas the more soluble compound remains in the solution. 

Furthermore, the other liquor is left out after this process, and the less soluble compound obtained is again concentrated, and then we allow it for later cooling. In this way, the more soluble compound and the crystals are obtained. 

• Sublimation

There are several substances that can go through the air state without undergoing the liquid state. Thus, sublimation is the process that exploits the property with the help of the purification of organic compounds by crystallization. These are important in discriminating the non-sublimely compounds from the sublimely compounds. 

In this process, the substance is put in a chain reaction wherein the top of the inverted funnel is provided to collect all the sublimable compounds. The vapors present in the funnel further get solidified in the funnel.

• Solvent Extraction

This method of purification of organic compounds by crystallization is performed for immiscible liquids, which means liquids that do not mix together. For instance, water and oil are immiscible liquids.

The liquids are obtained in a separating funnel and left undisturbed to perform this. After some time, they are separated with their own gravities, with the lighter liquid at the top. Then these are collected. Also, this can be performed based on their preferential solubility. 

• Chromatography

This is another essential method of purification of the organic compounds where separation of constituent particles present in a mixture takes place to obtain the purified compounds further and check the purity of the compounds. This process occurs in a stationary phase where the mixture is applied. IT is a mixture of gas or the pure solvent that is allowed to move slowly. These are further divided into two categories that include:

• Partition chromatography, and
• Adsorption chromatography.

• Distillation

The distillation is a process where the separation is performed by understanding the difference in the boiling points. The boiling point is the temperature where the atmospheric pressure equals the vapor pressure. Typically, it separates the volatile liquid from the non-volatile one. This process is further divided into four categories:

• Vacuum Distillation
• Simple Distillation 
• Fractional distillation
• Steam distillation

Conclusion

There are some brief studies about the method of purification of an organic compound and its various dimensions. This is the base topic for understanding the whole process used in the purification of organic compounds class 11.