Perkin Reaction Mechanism

Dhristi JEE 2022-24

About Organic Chemistry

There is no denying the fact that students have some of the most polarizing opinions when it comes to organic chemistry. Organic Chemistry is definitely a field of chemistry that has been loved and hated equally by the students. Maybe hated more than it is loved. If you ask us, then we would say that organic chemistry is the most misunderstood part of chemistry in general. What not a lot of students understand is that Organic Chemistry is supposed to be studied well instead of being memorized well. One must know how things work in order to excel and get great marks in Organic Chemistry. By being aware of the entire process of reactions in organic chemistry, students can easily score well and start loving the chapters involved in Organic Chemistry as well. 

 

So instead of memorization being the prime focus in every student’s strategy to score well in organic chemistry, what Vedantu recommends is to completely and thoroughly understand what is being talked about in the subject. We suggest that you spend a good amount of time understanding the ingredients and components of a reaction before you jump to memorizing the equation as a whole. When you start learning the main idea and concept behind what is being taught in organic chemistry, only then you will be able to love the subject completely. The easiest part of the process is that you do not have to look anywhere else for amazing free resources that can be downloaded for free when you have Vedantu by your side. 

 

The official Vedantu website and the app have a great number of brilliant resources that can be accessed for free to develop a good sense of liking for any subject of your choice. We believe that students can easily be able to love and enjoy any subject that they find, once they can understand what is the main principle behind everything that is being taught and talked about in every single subject, they will notice a difference in the way they approach their studies. 

 

With that being said, we present to you a very detailed and well-written article that was curated with the same intention in mind, to make sure that students are getting a good idea of the main concept of the Perkin Reaction Mechanism is. So get your pen and notepad ready, and let the learning begin!

 

Mechanism of Perkins Reaction

Perkin’s reaction is an organic reaction proposed by William Henry Perkin, an English Chemist, in the year 1868. The reaction belongs to the Carbonyl compounds and is used to make ɑ-, and β-unsaturated aromatic acids. Perkin used this reaction to make cinnamic acids. When an acid anhydride and aromatic aldehyde react with each other in the presence of a weak base, they condense to give the desired product. Condensation means the removal of water. The reaction is generally used in the synthesis of phytoestrogenic stilbene resveratrol in the laboratory. We will describe the mechanism of Perkins reaction and the step-by-step mechanism of perkin condensation under this topic.

 

Perkins Reaction With Mechanism

As mentioned above, the Perkin mechanism involves the condensation of an aldehyde and carboxylic acid anhydride with a weak base acting as a catalyst. Mainly, Sodium or Potassium salt of an acid is used which results in the formation of unsaturated aromatic acids. Perkin performed this reaction using the sodium salt of salicylaldehyde and acid anhydride, after heating this mixture at 453K, coumarin was obtained as the final product.

 

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Perkin Condensation Reaction Mechanism

The steps involved in the mechanism of Perkin condensation reaction are as follows.

  • The first step involves the removal of H+ ions using a weak base by carboxylate ion, which results in the formation of resonance stabilized carbanion, i.e., a species involving carbon-containing negative charge.

  • The second step involves the nucleophilic addition of the carbanion to the carbonyl carbon of aldehyde which will result in the formation of a tetrahedral intermediate.

  • The third step involves protonation of the tetrahedral intermediate by acetic acid which is formed in-situ. 

  • The fourth step involves condensation, i.e., the removal of a water molecule from the hydroxy derivative.

  • The last step involves hydrolysis, i.e., breaking of bonds using water, resulting in the formation of unsaturated acid as the product.


This is the most accepted and simplest mechanism of the Perkin reaction so far. There are various approaches suggested, so a few steps may differ. So, here we have explained the Perkin reaction with a mechanism.

 

Applications of Perkin Reaction Mechanism

  • Perkin Condensation is used for the synthesis of cinnamic acid in laboratories. Cinnamic acids are naturally occurring unsaturated aromatic carboxylic acids that are found commonly in cinnamon and shea butter.

  • It is used to synthesize ɑ-, and β-unsaturated aromatic acids, which are greatly used in the pharmaceutical sector.


To Conclude

We hope that the article on Perkin Reaction Mechanism by Vedantu was able to solve all the doubts that you possibly had about the topic. It is a very interesting topic that requires a good amount of focus and a very easy to understand method of teaching that can clarify all the tiny details from the concept. Vedantu guarantees that if you go through this article again and again in the future, you will be able to easily grasp all the key points and important parts of the concept and will definitely score well!

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FAQs (Frequently Asked Questions)

1. Which catalyst is used in the Perkin condensation mechanism?

The Perkins Condensation mechanism involves sodium or potassium salts of acid as a catalyst. These alkali salts act as a weak base that is suitable for this reaction because stronger bases result in undesirable changes in the aromatic entities present in the reaction.

2. Which Intermediate is Involved and what is the final product of Perkin reaction?

Intermediates are formed during the reactions, which cannot be isolated and they are theoretically assumed to plan how the mechanism would be. The intermediate involved in the reaction is the Tetrahedral entity which is formed by an attack of carbanion on the carbonyl carbon. The end product formed in the perkin reaction is ɑ,β-unsaturated aromatic acid.

3. Describe the Perkin reaction and the mechanism of Perkins’s reaction.

Perkin Reaction is a type of chemical reaction that involves the aldol condensation of an organic acid anhydride and an aromatic aldehyde to yield an ɑ, 𝛃-unsaturated aromatic acid.


Benzaldehyde when heated with acetic anhydride in the presence of sodium acetate it forms cinnamic acid as a product.


C2 H5​ CH=O + CH−CO−O−COCH3 →  C5H5CH=CH−COOH + CH3 COOH3


Perkins’s condensation mechanism consists of five steps. The first step involves deprotonation using a weak base. The second step involves the formation of a carbanion. The third step involves the Attack of this carbanion on the carbon of the carbonyl compound. The fourth step involves condensation and the last step involves hydrolysis which results in the formation of the final product.

4. Where do I find the best resources for Organic Chemistry?

As mentioned at the beginning of the article, how you study chemistry plays a major role in understanding what the entire subject will be perceived as by students. We are sure that there are some subjects that you do not like or enjoy but some of your friends may like it or feel otherwise. However, with Vedantu, enjoying subjects has become easier than ever. You can visit the official website and the app to download some high-quality study material for free for the subjects and topics involved in Organic Chemistry. Visit the website or download the app now! 

5. How do I memorize complex reaction equations for Organic Chemistry?

To memorize equations from organic chemistry, you must be well aware and acquainted with the main idea behind every equation. Take the Perkin Reaction for example. Instead of memorizing the equation blindly, it is much better to understand the mechanism behind it and then try to memorize it. Start getting to know the idea behind what the equation is about and write the equation multiple times to review it in the future and you will become a master at organic chemistry in no time!

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