Gattermann Reaction - Mechanism, Examples, Application, FAQs

Edited By Team Careers360 | Updated on Jul 02, 2025 04:50 PM IST

The Gattermann reaction, ( which is also known to be the Gattermann formylation or the Gattermann salicylaldehyde synthesis reaction ) is a type of chemical reaction through which an aromatic compounds will be formylated with the help of a mixture of hydrogen cyanide i.e.HCN and hydrogen chloride i.e. HCL in the presence of a Lewis acid catalyst for example AlCl₃. This reaction is named after a German chemist Ludwig Gattermann and this reaction is similar to the Friedel–Crafts reaction.

This Story also Contains

Q- Gattermann reaction
Applications of Gattermann Formylation Reaction
Q- Gattermann reaction class 12?
Points to know:-

This reaction can be easily understand by changing the HCN/AlCl₃ combination with zinc cyanide. Despite that it is also very toxic, Zn(CN)₂ is a solid, and making it safer to work in this reaction than gaseous HCN. Then Zn (CN)₂ will be able to reacts with HCl for the synthesis of a very important HCN reactant and Zn (Cl)₂ then will serves as the Lewis-acid catalyst in in-situ condition. An example of the Zn (CN)₂ used method is in the formation of mesitaldehyde from mesitylene.

Also read -

Q- Gattermann reaction

This reaction is Named after:

A German chemist, known as Ludwig Gattermann

The gattermann reaction can be discussed as a method in the process of formylation of aromatic ring compounds. Another names of this reaction are Gattermann salicylaldehyde synthesis and gattermann formylation. The gattermann reaction mechanism is very similar to that of Friedel-Crafts reaction.

Another use of Gattermann reaction is the preparation of halobenzene from benzenediazonium salt by treating with Cu/HX.

Q- Explain Gattermann reaction mechanism?

Step 1: The Formation of Formimino Chloride when HCN reacts with HCl for the synthesis of formimino chloride and leads to the formation of Formimino Chloride.

Step 2: Next step will be the Formation of Electrophile: Formimino chloride when reacts with a lewis acid catalyst like AlCl₃ then it will form Formimino cation.

Step 3: There will be Attack of Electrophile on Benzene Ring: The formimino Cation then reacts with the benzene ring to become Benzaldimine by the process of Attack of Electrophile on Benzene Ring

Step 4: There will be Hydrolysis of Benzaldimine: Hydrolysis of benzaldimine occurs which results to the formation of benzaldehyde.

Q- Gattermann synthesis?

It is the process that is used in the synthesis of aromatic ring compounds for example aromatic halides or aromatic aldehydes. This process is very similar to that of the Friedel-Crafts reaction. This process is named after a German Chemist Ludwig Gattermann. This process is also known to be Gattermann Formylation. In this reaction for the synthesis of aromatic halide diazonium salt will reacts with copper powder in presence of respective halogen acid. This reaction is generally a type of substitution reaction.

Applications of Gattermann Formylation Reaction

This reaction is used for the synthesis of chlorobenzene and bromobenzene.
Thia reaction is used for the synthesis of benzaldehydes.
Products of Gattermann formylation reaction like benzaldehydes and haloarenes etc. Are widely used in various fields like pharmaceuticals, agricultural, medicinal etc.
This reaction is used for the synthesis of aromatic halides and aromatic aldehydes.
Formation of Aromatic Aldehyde through Gattermann Reaction
Gattermann Formylation Reaction Mechanism
Mechanism of Gattermann Reaction have to be explained for the synthesis of aromatic aldehydes. Reaction takes place through the given four steps
Step 1. Synthesis of Formimino Chloride
Hydrogen cyanide when reacts with hydrogen chloride then it forms formimino chloride as a product.
Step 2. Synthesis of Electrophile
Formimino chloride when reacts with lewis acid catalyst (like AlCl₃) will forms formimino cation.
Step 3. Attacking of Electrophile to the Benzene Ring
Formimino cation (electrophile) will attacks on the benzene rings and leads to the formation of benzylamine.
Step 4. Hydrolysis or addition of water to Benzylamine
Hydrolysis of benzylamine will be taken place in this step. Which then results in the synthesis of benzaldehyde.

Related Topics Link,

NEET Highest Scoring Chapters & Topics

This ebook serves as a valuable study guide for NEET exams, specifically designed to assist students in light of recent changes and the removal of certain topics from the NEET exam.

Download EBook

How is Diazonium Salt will be Formed?

Aromatic amine when reacts with nitrous acid and mineral acid then it will forms diazonium salt and also produces water as a by product. This reaction is well known as Diazotization Reaction.

Gattermann reaction of diazonium salt is shown below.

ArNH₂ + HNO₂ + HX ? RN₂⁺X^- + H₂O

Aromatic amine nitrous acid mineral acid Diazoniumsalt water

Q- Gattermann reaction class 12?

Gattermann Reaction → In this reaction halogen group is added to the benzene ring when treated with solution of benzene diazonium salt along with halogen acid in presence of copper powder

Gattermann Reaction example

C₆H₅−N₂ + Cl−Cu + HCl (X=Cl,Br) --> C₆H₅−Cl + N₂
It is the process that is used in the synthesis of aromatic ring compounds for example aromatic halides or aromatic aldehydes. This process is very similar to that of the Friedel-Crafts reaction. This process is named after a German Chemist Ludwig Gattermann. This process is also known to be Gattermann Formylation. In this reaction for the synthesis of aromatic halide diazonium salt will reacts with copper powder in presence of respective halogen acid. This reaction is generally a type of substitution reaction.

Q- Gattermann aldehyde synthesis or Gattermann aldehyde reaction?

This reaction involves carbon compounds and the derivatives of carbon due to this property this reaction is known as organic reactions. Gatterman aldehyde synthesis is a type of an organic reaction that is used in the formation of aromatic aldehydes.

Carbon or the derivatives of carbon will be considered as organic compounds and the reactions including organic compounds will be known as organic reactions. Gatterman aldehyde synthesis is a type of an organic reaction and as we can easily observe in its name that this reaction is used to form aldehydes. This process is mostly used in case of aromatic compounds due to the fact that stable products are available only for aromatic compounds. The aromatic compounds will be converted into aldehydes with the help of hydrogen cyanide, hydrogen chloride and a Lewis acid like aluminium chloride.
The reaction will be represented as follows:
Step1.

1639625662417

Step2.

Gattermann aldehyde synthesis or Gattermann aldehyde reaction
In step one as we can observe that hydrogen cyanide will reacts with hydrochloric acid and aluminium chloride to form a new better nucleophile that can attack on aromatic compound like benzene.
In step two the reagents attacks on benzene will forms a product releasing aluminium chloride and on further reacting with water it again releases ammonium chloride and then we will get our final product benzaldehyde.
So this is the mechanism of Gatterman aldehyde synthesis reaction.
Gatterman aldehyde synthesis reaction is very similar to that of friedel craft reaction. As we know when an alkyl group will be added to a benzene ring through electrophilic substitution reaction, then this process is called as friedel craft alkylation and the same mechanism is happening in gattermann aldehyde synthesis and only the difference is that the group attached is different, in this process we are adding an aldehyde group to the benzene ring.

Also Read:

Points to know:-

A reaction that is similar to Gatterman aldehyde synthesis also exists in organic chemistry and that reaction is known as Gatterman Koch synthesis. The functional group added in both the reactions are same and the only difference is that their reagents are not same. Carbon monoxide is used as reagent in Gatterman Koch synthesis.

Q- What is gattermann reaction ?

In this reaction benzene diazonium salt is reacted with halogen acid in presence of copper catalyst to form chloro benzene or bromo benzene.

C₆H₅−N₂ + X−Cu + HX (X=Cl,Br) --> C₆H₅−X + N₂

Also check-

NCERT Chemistry Notes:

Frequently Asked Questions (FAQs)

1. Can the Gattermann reaction be used in industrial processes?

While the Gattermann reaction has been used in some industrial processes, its use is limited due to safety concerns associated with HCN. Alternative methods or modified versions of the reaction are often preferred in large-scale production.

2. What types of aromatic compounds work best in the Gattermann reaction?

The Gattermann reaction works best with activated aromatic compounds, particularly phenols and their ethers. These compounds have electron-donating groups that make them more reactive towards electrophilic aromatic substitution.

3. Can the Gattermann reaction be used on benzene?

No, the Gattermann reaction is not effective on unactivated aromatic compounds like benzene. It requires more activated aromatic rings with electron-donating groups to proceed efficiently.

4. Can the Gattermann reaction be used to introduce multiple aldehyde groups?

While it's theoretically possible, introducing multiple aldehyde groups using the Gattermann reaction is challenging and not commonly done. The first aldehyde group deactivates the ring towards further substitution.

5. What are the main advantages of the Gattermann reaction?

The main advantages are: 1) Direct introduction of an aldehyde group onto an aromatic ring, 2) Use of relatively inexpensive reagents, 3) Generally good yields for activated aromatics.

6. How does the Gattermann reaction differ from the Gattermann-Koch reaction?

The Gattermann reaction uses HCN and HCl, while the Gattermann-Koch reaction uses carbon monoxide (CO) and HCl. The Gattermann reaction is typically used for phenols and other activated aromatic compounds, whereas the Gattermann-Koch reaction can be applied to less activated aromatics.

7. What is the role of the Lewis acid catalyst in the Gattermann reaction?

The Lewis acid catalyst (usually AlCl3 or ZnCl2) activates the HCN by forming a complex with it. This complex then acts as the electrophile in the reaction, making it more reactive towards the aromatic ring.

8. Why is the Gattermann reaction considered a formylation reaction?

The Gattermann reaction is considered a formylation reaction because it introduces a formyl group (-CHO) onto the aromatic ring, effectively converting it into an aromatic aldehyde.

9. What is the mechanism of the Gattermann reaction?

The mechanism involves several steps: 1) Formation of the electrophile (HCN-AlCl3 complex), 2) Electrophilic aromatic substitution on the aromatic ring, 3) Hydrolysis of the intermediate imine to form the aldehyde.

10. Why is HCl used in the Gattermann reaction?

HCl serves two purposes: it helps in the formation of the electrophilic species and assists in the final hydrolysis step to convert the imine intermediate into the aldehyde product.

11. What is the Gattermann reaction?

The Gattermann reaction is an electrophilic aromatic substitution reaction used to introduce an aldehyde group (-CHO) directly onto an aromatic ring. It involves the use of hydrogen cyanide (HCN) and hydrogen chloride (HCl) in the presence of a Lewis acid catalyst, typically anhydrous aluminum chloride (AlCl3) or zinc chloride (ZnCl2).

12. How does the electronic nature of substituents on the aromatic ring affect the Gattermann reaction?

Electron-donating substituents (e.g., -OH, -OR, -NR2) activate the ring and facilitate the reaction. Electron-withdrawing groups (e.g., -NO2, -COOH) deactivate the ring and can hinder or prevent the reaction.

13. What are some limitations of the Gattermann reaction?

Limitations include: 1) Limited to activated aromatic compounds, 2) Use of toxic HCN, 3) Sensitivity to moisture, 4) Potential for side reactions.

14. What is the significance of anhydrous conditions in the Gattermann reaction?

Anhydrous conditions are crucial because water can hydrolyze the HCN and the Lewis acid catalyst, reducing their effectiveness. Water can also lead to unwanted side reactions and lower yields.

15. What are some common side reactions in the Gattermann reaction?

Common side reactions include: 1) Formation of diaryl ketones, 2) Polymerization of HCN, 3) Hydrolysis of the imine intermediate before it can react with the aromatic ring.

16. What is the role of zinc cyanide (Zn(CN)2) in some variations of the Gattermann reaction?

Zinc cyanide can be used as a safer alternative to HCN in some variations of the Gattermann reaction. It serves as a source of cyanide ions and can be used in conjunction with HCl and a Lewis acid catalyst.

17. How does the reactivity of phenol compare to anisole in the Gattermann reaction?

Phenol is generally more reactive than anisole in the Gattermann reaction. This is because the -OH group in phenol is more strongly activating towards electrophilic aromatic substitution than the -OCH3 group in anisole.

18. How does the orientation of the aldehyde group in the product depend on the starting material?

The aldehyde group typically enters the ortho or para position relative to the activating group on the aromatic ring. For phenols and ethers, para substitution is usually favored due to less steric hindrance.

19. How does the Gattermann reaction compare to other methods of introducing aldehyde groups onto aromatic rings?

The Gattermann reaction is often simpler and more direct than multi-step methods like oxidation of a methyl group or reduction of a carboxylic acid. However, it's limited to activated aromatics and uses toxic HCN, unlike some other methods.

20. How does temperature affect the Gattermann reaction?

Temperature control is important in the Gattermann reaction. Higher temperatures can increase the reaction rate but may also lead to side reactions or decomposition of reagents. The reaction is typically carried out at moderate temperatures (0-30°C).

21. What safety precautions should be taken when performing the Gattermann reaction?

Key safety precautions include: 1) Use of a fume hood due to toxic HCN, 2) Proper personal protective equipment (gloves, goggles, lab coat), 3) Anhydrous conditions to prevent unwanted side reactions, 4) Proper disposal of waste materials.

22. What is the importance of the imine intermediate in the Gattermann reaction mechanism?

The imine intermediate is crucial as it forms after the initial electrophilic attack on the aromatic ring. Its hydrolysis in the final step leads to the formation of the desired aldehyde product.

23. How can you confirm the success of a Gattermann reaction?

The success of a Gattermann reaction can be confirmed through various analytical techniques, including: 1) IR spectroscopy (look for C=O stretch), 2) NMR spectroscopy (aldehyde proton peak), 3) Mass spectrometry, 4) 2,4-Dinitrophenylhydrazine test for aldehydes.

24. What are some alternatives to the Gattermann reaction for introducing aldehyde groups?

Alternatives include: 1) Vilsmeier-Haack reaction, 2) Reimer-Tiemann reaction, 3) Oxidation of primary alcohols or methylbenzenes, 4) Reduction of acid chlorides (Rosenmund reduction).

25. How does the Gattermann reaction relate to green chemistry principles?

The Gattermann reaction has some challenges in terms of green chemistry: 1) Use of toxic HCN, 2) Requirement for stoichiometric amounts of Lewis acid catalyst. However, it's a direct, one-step method that can be efficient in terms of atom economy for suitable substrates.

26. Can the Gattermann reaction be performed on heterocyclic compounds?

The Gattermann reaction can be performed on some electron-rich heterocyclic compounds, such as furans and thiophenes. However, it's less commonly used for heterocycles compared to carbocyclic aromatic compounds.

27. What is the effect of steric hindrance on the Gattermann reaction?

Steric hindrance can significantly affect the Gattermann reaction. Bulky substituents near the reactive sites on the aromatic ring can slow down the reaction or change the orientation of the incoming aldehyde group.

28. How does the Gattermann reaction compare to the Friedel-Crafts acylation in terms of product formation?

While both reactions introduce a carbonyl group, the Gattermann reaction forms an aldehyde (-CHO), whereas the Friedel-Crafts acylation forms a ketone (-COR). The Gattermann reaction is also more limited in terms of substrate scope.

29. What is the role of the solvent in the Gattermann reaction?

The solvent in the Gattermann reaction should be anhydrous and inert. Common choices include diethyl ether or carbon disulfide. The solvent helps to dissolve the reactants and can influence the reaction rate and yield.

30. How does the Gattermann reaction demonstrate the concept of electrophilic aromatic substitution?

The Gattermann reaction is a classic example of electrophilic aromatic substitution. It shows how an electrophile (the HCN-AlCl3 complex) can attack the electron-rich aromatic ring, replacing a hydrogen atom with a new functional group (aldehyde).

31. What is the significance of regioselectivity in the Gattermann reaction?

Regioselectivity in the Gattermann reaction determines where the aldehyde group will be introduced on the aromatic ring. It's influenced by the existing substituents and follows the general rules of electrophilic aromatic substitution (ortho/para directors vs. meta directors).

32. How does the Gattermann reaction exemplify the concept of in situ generation of reagents?

The Gattermann reaction demonstrates in situ generation of reagents through the formation of the reactive electrophile. The HCN-AlCl3 complex is generated in the reaction mixture rather than being added as a pre-formed reagent.

33. Can the Gattermann reaction be used in the synthesis of pharmaceuticals or natural products?

Yes, the Gattermann reaction can be used in the synthesis of some pharmaceuticals and natural products, particularly those containing aromatic aldehydes. However, its use may be limited due to safety concerns and substrate limitations.

34. How does the presence of halogen substituents on the aromatic ring affect the Gattermann reaction?

Halogen substituents (F, Cl, Br, I) are generally ortho/para directors in electrophilic aromatic substitution. They can facilitate the Gattermann reaction, but their electron-withdrawing nature may slightly reduce the ring's reactivity compared to more strongly activating groups.

35. What is the importance of workup procedures in the Gattermann reaction?

The workup procedures in the Gattermann reaction are crucial for: 1) Hydrolyzing the imine intermediate to form the aldehyde, 2) Neutralizing excess acid, 3) Removing the Lewis acid catalyst, 4) Extracting and purifying the product.

36. How does the Gattermann reaction demonstrate the principle of chemoselectivity?

The Gattermann reaction shows chemoselectivity by specifically introducing an aldehyde group rather than other carbonyl groups (like ketones) or other functional groups. This selectivity is due to the specific reagents and mechanism involved.

37. Can the Gattermann reaction be performed under mild conditions?

The Gattermann reaction typically requires moderately harsh conditions (strong acid, anhydrous environment). Mild conditions are generally not sufficient for this reaction, which is one of its limitations.

38. How does the Gattermann reaction relate to the concept of carbon electrophiles in organic chemistry?

The Gattermann reaction involves a carbon electrophile (the HCN-AlCl3 complex) attacking the aromatic ring. This demonstrates how carbon can act as an electrophile under certain conditions, contrary to its usual nucleophilic nature.

39. What role does kinetics play in the Gattermann reaction?

Kinetics is important in the Gattermann reaction, affecting the rate of formation of the electrophile, the rate of electrophilic attack on the aromatic ring, and the rate of hydrolysis of the imine intermediate. These factors influence the overall reaction time and yield.

40. How does the Gattermann reaction showcase the importance of leaving groups in organic reactions?

In the Gattermann reaction, the hydrogen atom on the aromatic ring acts as the leaving group. This demonstrates that even a simple proton can serve as a leaving group in suitable reactions, particularly in electrophilic aromatic substitution.

41. Can the Gattermann reaction be used in the synthesis of aromatic dialdehyde compounds?

While theoretically possible, synthesizing aromatic dialdehydes using the Gattermann reaction is challenging. The first aldehyde group deactivates the ring, making the second formylation difficult. Sequential reactions or alternative methods are often preferred for dialdehyde synthesis.

42. How does the concept of resonance stabilization apply to the Gattermann reaction?

Resonance stabilization is crucial in the Gattermann reaction. The intermediate formed after electrophilic attack is stabilized by resonance within the aromatic ring, which drives the reaction forward. This stabilization also influences the regioselectivity of the reaction.

43. What is the environmental impact of the Gattermann reaction?

The environmental impact of the Gattermann reaction is a concern due to: 1) Use of toxic HCN, 2) Generation of acidic waste, 3) Use of metal catalysts. These factors make it less environmentally friendly compared to some alternative methods.

44. How does the Gattermann reaction demonstrate the concept of functional group interconversion?

The Gattermann reaction demonstrates functional group interconversion by effectively converting a C-H bond on the aromatic ring into a C-CHO group. This showcases how reactions can be used to transform one functional group into another.

45. Can the Gattermann reaction be adapted for use in flow chemistry?

Adapting the Gattermann reaction for flow chemistry is challenging due to the use of gaseous HCN and the heterogeneous nature of the reaction (solid catalyst). However, modified versions using safer cyanide sources might be adaptable to flow conditions with careful engineering.

46. How does the Gattermann reaction relate to the concept of carbon-carbon bond formation in organic synthesis?

The Gattermann reaction is an example of carbon-carbon bond formation, specifically creating a new C-C bond between the aromatic ring and the aldehyde carbon. This demonstrates the importance of C-C bond-forming reactions in building molecular complexity.

47. What role does thermodynamics play in the Gattermann reaction?

Thermodynamics is important in the Gattermann reaction, influencing the overall feasibility and direction of the reaction. The formation of a stable aromatic aldehyde product and the release of HCl provide a thermodynamic driving force for the reaction.

48. How does the Gattermann reaction showcase the importance of understanding reaction mechanisms in organic chemistry?

Understanding the mechanism of the Gattermann reaction is crucial for predicting its outcomes, optimizing conditions, and troubleshooting issues. It demonstrates how knowledge of reaction mechanisms can guide synthetic planning and problem-solving in organic chemistry.

49. Can the principles of the Gattermann reaction be applied to other types of organic transformations?

The principles of the Gattermann reaction, such as electrophilic aromatic substitution and in situ generation of reactive species, can be applied to other organic transformations. This showcases how understanding one reaction can provide insights into broader chemical concepts.

50. How does the Gattermann reaction contribute to our understanding of aromatic chemistry?

The Gattermann reaction enhances our understanding of aromatic chemistry by demonstrating: 1) The reactivity of aromatic rings towards electrophiles, 2) The influence of substituents on reactivity and selectivity, 3) The ability to functionalize aromatic compounds directly. It serves as a valuable tool for studying and manipulating aromatic systems.