Quick Reference: Major Name Reactions and Their Mechanisms
Name reactions are those chemical reactions that are named after the scientists who discovered or developed them. This trend started in 1822 with scientist Lieben. He studied the reaction of many carbonyl compounds with iodine and alkali and postulated rules that formed the basis of the iodoform test. This is the reason the reaction was named after Lieben and was called LIeben Haloform Reaction. Presently, hundreds of well-known organic reactions have been named after scientists. All these name reactions are very important for board examinations and competitive exams such as IIT JEE, NEET etc.
Importance of Name Reactions
If you are in class 12, then all name reactions are very important to score well in the board exam and clear JEE or NEET exams. Here we are providing you with a list of important named reactions in organic chemistry, which will be handy for you during revision. We have linked listed named reactions with separate pages as well in which named reactions are given with detailed descriptions, mechanisms and applications.
List of Important Name Reactions in Organic Chemistry
Friedel Crafts Alkylation Reaction
By this reaction, alkyl benzene is formed by the reaction of the aromatic compound and alkyl halide in the presence of Friedel craft catalyst (AlCl3). For more details, visit the following pages on Vedantu– Friedel Crafts Reaction.
Friedel Crafts Acylation Reaction
By this reaction, a monoacyl aromatic compound is formed by the reaction of an acylating agent and aromatic compound in the presence of Friedel craft catalyst. For more details, visit the following pages on Vedantu– Friedel Crafts Reaction.
Mannich Reaction
In this reaction, 1° or 2° amine/ ammonia reacts with non-enolizable aldehyde and enolizable carbonyl compounds to form a Mannich base. For more details on mannich reaction, visit the following page on Vedantu–Mannich Reaction.
Hoffmann Bromamide Degradation Reaction
In Hoffmann bromamide degradation reaction, an amide reacts with bromine and an aqueous solution of sodium hydroxide which produces primary amine. For more details, visit the following pages on Vedantu– Hoffmann Bromamide Reaction Mechanism.
Rosenmund Reduction Reaction
In the Rosenmund Reaction, acyl chloride is hydrogenated to get reduced into aldehyde, and palladium-barium sulphate is used as a catalyst. For more details, visit the following pages on Vedantu– Rosenmund Reduction Mechanism.
Hofmann Elimination Reaction
Tertiary amines and alkenes are formed by Hofmann elimination reaction. For more details, visit the Hofmann Elimination article page on Vedantu.
Cannizzaro Reaction
In this reaction, one molecule of aldehyde is oxidized to carboxylic acid, and another molecule of aldehyde is reduced to an alcohol. For more details, visit the following pages on Vedantu– Cannizzaro Reaction Mechanism.
Wurtz Reaction
It is a coupling reaction in which two alkyl halides react with sodium to form a new alkane. For more details, visit Wurtz Reaction and Important Chemical Reactions for Class 12 Chemistry pages on Vedantu.
Swartz Reaction
It is a halogen exchange reaction in which alkyl halide is used as one of the reactants. For more details, visit Swartz Reaction and Important Chemical Reactions for Class 12 Chemistry pages on Vedantu.
Perkin Reaction
It is used to make cinnamic acids. It gives α,β-unsaturated aromatic acid by aldol condensation. For more details, visit the Perkin Reaction Mechanism page on Vedantu.
Sandmeyer Reaction
In the Sandmeyer reaction, a product of diazotization reaction, which is diazonium salt, is used to synthesize aryl halides.
Gattermann Reaction
It is used in the synthesis of aromatic ring compounds such as aromatic halides and aromatic aldehydes.
Balz-Schiemann Reaction
This reaction is used in the formation of fluorobenzene.
Finkelstein Reaction
The reaction in which alkyl iodides are prepared by the reaction of alkyl chloride or alkyl bromide with sodium iodide in dry acetone is called Finkelstein Reaction.
Fittig Reaction
When aryl halides react with metallic sodium in the presence of dry ether, it forms biphenyl as a major product. Then this reaction is known as the Fittig Reaction.
Reimer – Tiemann Reaction
In the Reimer – Tiemann reaction, phenol reacts with chloroform in the presence of sodium hydroxide, as a result of which an aldehyde group gets attached to the ortho position of the ring.
Kolbe’s Reaction
This reaction gives 2-hydroxybenzoic acid or salicylic acid by using phenol, sodium hydroxide and carbon dioxide.
Stephen Reaction
In Stephen Reaction, nitrile reacts with SnCl2 in the presence of HCl and gives imine hydrochloride, which on hydrolysis gives aldehyde.
Gattermann – Koch Reaction
In the Gattermann – Koch reaction, benzene is treated with carbon monoxide in the acidic medium in the presence of anhydrous aluminium chloride to give benzaldehyde.
Clemmensen Reduction Reaction
In the Clemmensen reduction reaction, the carbonyl group of aldehydes and ketones on reaction with zinc amalgam and conc. HCl is reduced to their corresponding hydrocarbon.
Wolff Kishner Reduction Reaction
In Wolff Kishner Reduction Reaction, the carbonyl group of aldehydes and ketones reacts with hydrazine and forms hydrazone, which on heating with sodium hydroxide in boiling ethylene glycol reduces to CH2 group.
Aldol Condensation
In an aldol condensation reaction, two molecules of an aldehyde or ketones get condensed and form β - hydroxy aldehyde or β - hydroxy ketone, respectively, in the presence of dilute alkali.
Carbylamine Reaction
When aliphatic or aromatic primary amines are heated with chloroform, and ethanolic potassium hydroxide produces carbyl amines or isocyanides. This reaction is known as the carbylamine reaction.
For more details, visit the Important Chemical Reactions for Class 12 Chemistry page on Vedantu.
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FAQs on Essential Name Reactions in Organic Chemistry
1. What are name reactions in organic chemistry?
Name reactions are specific chemical reactions that are named after the scientists who discovered or significantly developed them. They are essential tools in organic synthesis for creating specific functional groups or carbon skeletons. For example, the Wurtz reaction is named after Charles Adolphe Wurtz and is a well-known method for synthesising alkanes.
2. Why are name reactions given special importance in organic chemistry studies?
Name reactions are important because they represent reliable and well-studied methods for specific chemical transformations. They often provide the most efficient pathway to synthesise a particular type of compound. For students, mastering these is crucial as they frequently appear in CBSE board exams and competitive tests like JEE and NEET, often as part of conversion or mechanism-based questions.
3. How many name reactions are important for the CBSE Class 12 Chemistry syllabus 2025-26?
The CBSE Class 12 Chemistry syllabus for the 2025-26 session features approximately 15-20 key name reactions across the organic chemistry units. These include reactions from chapters like Haloalkanes and Haloarenes, Alcohols, Phenols and Ethers, Aldehydes, Ketones and Carboxylic Acids, and Amines. Important examples include the Sandmeyer, Aldol Condensation, Cannizzaro, and Hoffmann Bromamide reactions.
4. What is the key difference between the Wurtz reaction and the Fittig reaction?
The primary difference lies in the type of halide used as the reactant.
- The Wurtz reaction involves the coupling of two alkyl halides in the presence of sodium metal to form a higher alkane.
- The Fittig reaction involves the coupling of two aryl halides (like chlorobenzene) to form a biaryl compound.
5. Explain the Reimer-Tiemann reaction with an example.
The Reimer-Tiemann reaction is a method for the ortho-formylation of phenols. In this reaction, phenol is treated with chloroform (CHCl₃) in the presence of a strong base like sodium hydroxide (NaOH). This process introduces an aldehyde group (-CHO) primarily at the ortho position of the benzene ring. For instance, reacting phenol with CHCl₃/NaOH yields salicylaldehyde (2-hydroxybenzaldehyde) as the major product.
6. How can you differentiate between the Clemmensen and Wolff-Kishner reductions?
Both reactions reduce a carbonyl group (C=O) of aldehydes and ketones to a methylene group (CH₂), but they operate under opposite pH conditions.
- Clemmensen Reduction: This method uses zinc amalgam (Zn-Hg) and concentrated hydrochloric acid (HCl). It is performed in a strongly acidic medium.
- Wolff-Kishner Reduction: This method uses hydrazine (N₂H₄) followed by a strong base like potassium hydroxide (KOH) in a high-boiling solvent. It is performed in a strongly basic medium.
7. What is Aldol Condensation, and which compounds undergo this reaction?
Aldol Condensation is a reaction where two molecules of an aldehyde or a ketone combine to form a β-hydroxy aldehyde (an aldol) or a β-hydroxy ketone, which may then dehydrate. The essential condition for a compound to undergo this reaction is the presence of at least one alpha-hydrogen atom. The reaction is typically catalysed by a dilute acid or a dilute base.
8. In the Cannizzaro reaction, why is it necessary for the aldehyde to not have an alpha-hydrogen?
The Cannizzaro reaction is a disproportionation reaction specifically for aldehydes that lack an alpha-hydrogen. If an alpha-hydrogen is present, a different reaction, the Aldol Condensation, will occur much faster in the presence of a base. The absence of the acidic alpha-hydrogen allows the hydroxide ion (OH⁻) to act as a nucleophile and attack the carbonyl carbon, initiating the Cannizzaro mechanism where one molecule is oxidised to a carboxylate salt and another is reduced to an alcohol.
9. What is the role of the catalyst, anhydrous AlCl₃, in Friedel-Crafts reactions?
In Friedel-Crafts reactions (both alkylation and acylation), anhydrous aluminium chloride (AlCl₃) functions as a Lewis acid catalyst. Its main purpose is to generate a powerful electrophile that can attack the benzene ring.
- In alkylation, it helps form a carbocation from an alkyl halide (e.g., R-Cl + AlCl₃ → R⁺ + [AlCl₄]⁻).
- In acylation, it helps form a more stable acylium ion from an acyl halide (e.g., RCOCl + AlCl₃ → RCO⁺ + [AlCl₄]⁻).
10. What type of product is formed in the Hoffmann Bromamide Degradation reaction?
The Hoffmann Bromamide Degradation reaction converts a primary amide into a primary amine that contains one carbon atom less than the starting amide. It is a step-down reaction, meaning it shortens the carbon chain. The reaction is carried out by treating the amide with bromine (Br₂) in an aqueous or ethanolic solution of sodium hydroxide (NaOH).
11. How does the Sandmeyer reaction provide a better yield than the Gattermann reaction?
Both the Sandmeyer and Gattermann reactions synthesise aryl halides from diazonium salts, but they differ in their catalyst.
- The Sandmeyer reaction uses a cuprous salt (CuCl, CuBr) dissolved in the corresponding halogen acid.
- The Gattermann reaction uses freshly prepared copper powder with the halogen acid.
12. What is the main application of the Finkelstein reaction?
The Finkelstein reaction is a halogen exchange method specifically used for preparing alkyl iodides. It involves reacting an alkyl chloride or alkyl bromide with sodium iodide (NaI) in dry acetone. The reaction's success is driven by Le Chatelier's principle, as the sodium chloride (NaCl) or sodium bromide (NaBr) formed is insoluble in acetone and precipitates out, pushing the reaction to completion.
