Important Questions on Tautomerism

This configuration change of the compound is a process called tautomerization. They are certain types of structural isomers. Structural isomers are all molecules that have the same chemical formula. What makes tautomers worthy of classification is that they easily interconvert between different morphologies. Many structural isomers do not easily convert to the corresponding isomers. 

The occurrence of tautomerization is not a consequence due to the intermolecular transferring of protons in between atoms of C and O atoms. A series of transfer steps of proton occur in between the solvent and the individual tautomers. The solvent behaves as an intermediate, receiving a singular proton from a certain kind of form to another. Both acids and bases can catalyse proton transfer. Hence, tautomerization occurs by two different mechanisms.

Explain Alpha Carbon Atom in Tautomerism

During the process of tautomerization, there is the atom movement. The carbon atom that comes closest to the functional group after its movement, is known as the alpha carbon atom. To make the entire process successful, there is a necessity of at least one hydrogen atom with the alpha carbon atom. This alpha carbon atom can also be known as the alpha hydrogen atom. 

Explain Stability of Keto-enol Form

A well-defined rule was developed by the scientist Emil Erlenmeyer in the 1880s. It soon became very important as he was able to properly study keto-enol tautomerism. According to the rule, the hydroxyl group in all alcohols is involved directly with a double-bonded carbon atom, and thus, it is much more stable. The keto-enol form is also the most popular form due to its stability. 

What is Ring-Chain Tautomerism

During the process of tautomerization, if the proton movement is seen to be accompanying the closing opening of a ring, it can be recognized as ring-chain tautomerism. If we consider carbohydrates, this form of tautomerization is most prevented but the ring-chain tautomerism can be witnessed in other molecules as well. Like any other form of tautomerism, to complete the ring-chain tautomerism, a definite set of rules or conditions must be followed. To identify whether or not a compound will be eligible for this type of tautomerism, the substructure needs to be detected. 

What are the Characteristics of Tautomerism

1. A movement of atoms can be witnessed in tautomerism and these atoms. 
2. Because the compounds are definite compounds, they can be separated and isolated as well.
3. There are two structures for tautomeric forms. 
4. No effect is experienced by the bond length due to tautomerism. 
5. All the compounds of the tautomer are in a state of equilibrium with each other. 
6. Tautomerism is not responsible for decreasing the energy of the molecules. Therefore, the molecules present are in a stable state. 
7. Tautomerism can be witnessed in both planar and non-planar molecules. 

Mention Different Types of Tautomerism 

There are many types of tautomerism. They are as follows:

1. Prototropy- This type of tautomerism is caused by the acid-base behavior of the compound and in this type of tautomerism, the two forms are only different in the proton’s position. This particular structure has the same empirical formula and the same number of charges. 
2. Annular Tautomerism- If a situation occurs when a proton is seen to be occupying two or more two positions of a heterocyclic system, it will be known as annular tautomerism. If an open structure is altered to a ring-like structure due to the delocalization of the protons, then it will be known as a ring-chain tautomer. Glucose is a great example of a ring-chain tautomer. 
3. Valence Tautomerism- This is another unique type of tautomerism. In this case, the process of tautomerism happens continuously and the formation of both the single and double bonds are off and running so that the compound is broken down without any atoms or groups migrating to different positions. This is a very rapid process and is much different from other types of tautomerism. 

Conclusion

A phenomenon where a single chemical compound is found to be existing in two or more structures and that structure is interconvertible. Here, it must be remembered that this situation is much different if we consider the relative position of only one atomic nucleus like hydrogen. In this case, the molecular formula remains the same but the spatial arrangement of the atoms is altered convincingly.