All You Need to Know About Schotten – Baumann Reaction
Schotten – Baumann reaction is used for commercial production of amides. It is the method of synthesis of amides by using acid chloride. It is named after German Chemists Carl Schotten and Eugen Baumann, as the reaction was first described by these two chemists in 1883.
Schotten – Baumann reaction is a condensation reaction of organic chemistry. In this reaction, acid chloride (acyl halide) or anhydride reacts with amine (primary or secondary) and base to produce amide. The general reaction is given below.
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Sometimes this reaction also indicates the reaction between acid chloride (acyl halide) or anhydride with alcohol and base to produce an ester. The general reaction is given below.
Examples of Schotten – Baumann Reaction
Schotten – Baumann reaction also refers to the benzoylation reaction of active hydrogen-containing compounds. Some examples of the Schotten – Baumann reaction are given below.
Benzoylation of phenol
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The reaction of benzylamine with acetyl chloride
The reaction of the acid chloride with primary amine
Benzoylation of aniline - reaction of the acid chloride with primary amine (aromatic)
Mechanism of Schotten -Baumann Reaction
The Schotten – Baumann reaction mechanism is given for the reaction of an amine with acid chloride and base. It can be explained by the following two steps:
Step 1. Attack by Nitrogen Atom of Amine on Carbonyl Carbon of Acyl Halide
The nitrogen atom of the secondary amine has a lone pair of electrons. So, it attacks the carbonyl carbon atom of acyl halide. Thus, the reaction begins. It leads to rearrangement of acyl halide and removal of halide. Thus, nitrogen gets attached with carbonyl carbon of acyl halide. The reaction is given below-
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Step 2. Deprotonation: Now the compound formed in step 1 reacts with the base. Hydrogen atoms attached with nitrogen combine with hydroxyl ions of base and form water molecules. Thus deprotonation takes place and nitrogen being more electronegative than hydrogen gets the electrons towards itself and forms amide. The reaction is given below-
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Applications of Schotten – Baumann Reaction
This reaction is widely used in synthesis in organic chemistry. Few applications of this reaction are given below.
It is used in the synthesis of N-vanillyl nonanamide or capsaicin.
It is used in the synthesis of benzamide from benzoyl chloride and phenethylamine.
It is used in the acylation of benzylamine.
It is used in Fischer's synthesis of peptides.
Products of this reaction such as ester and amides are very useful in many industries such as food, medicine etc.
It was all about the Schotten – Baumann reaction and its mechanism. If you are looking for more methods of preparation of amides and esters or other name reactions, then explore through our website.
Important Points About the Schotten-Baumann Reaction
The most important point about Schotten-Baumann's reaction that every student should remember are:
The Schotten-Baumann reaction of benzoylation of phenols is a very important reaction method in the field of organic chemistry.
The Schotten-Baumann reaction is named after two German scientists who discovered the reaction.
The reaction is mainly used in the field of organic chemistry for the benzoylation of phenols with benzoyl chloride.
The base catalysts that are used in the Schotten-Bauman reaction, to keep the medium of the reaction basic, are sodium hydroxide and pyridine because the reactants involved in the reaction are always acidic.
The phenol and the base involved in the reaction condition react to give phenoxide ion. Afterward, the benzoyl chloride is attacked by a phenoxide ion.
The negative charge prevalent in the reaction shifts to the oxygen molecule present in benzoyl chloride. The negative charge is then utilized to form a double bond between the oxygen atom and the carbon atom.
Since the carbon atom has the capability of forming only four bonds, the bond present between the carbon atom and the chlorine atom has to break. This bond breaks easily because of the electronegativity difference between the two atoms and the polar nature of the bond. This finally results in the formation of the final product, that is, phenyl benzoate.
The conditions of the Schotten-Baumann reaction make it easy to perform benzoylation of phenols.
The same condition of Schotten-Baumann can also be used for carrying out benzoylation of aromatic amines, synthesizing amides from acid chlorides and amines wherein acyl chlorides are reacted with amines to produce amides.
Apart from the stated above, the reaction can also be used in the synthesis of various compounds and chemicals in the laboratory.
FAQs on Schotten - Baumann Reaction
1. Summarise the steps involved in the mechanism of the Schotten-Baumann reaction.
The mechanism of the Schotten-Baumann reaction can be divided into three major steps. The first step involves the formation of a protonated compound by the reaction of amine and acyl chloride. The lone pair of electrons present on the nitrogen atom aid in the formation of a carbon-nitrogen bond thereby, neutralizing the positive and negative charges in the nitrogen and oxygen respectively by the exchange of portions between them.
The second step of the reaction involves the formation of the double bond of oxygen with the carbonyl carbon, thereby liberating an acidic proton which is absorbed by the base catalyst of the reaction.
The final step involves the formation of amide and hydrochloric acid which is also neutralized by the base catalyst present in the reaction.
2. What are the features of Schotten Baumann Reaction?
The Schotten Baumann reaction is also known as the benzoylation of active hydrogen-containing compounds in the presence of benzyl chloride and aqueous sodium hydroxide and the features of this reaction include:
For the Schotten-Baumann reaction to occur, a base is essential in order to shift the equilibrium towards the formation of amides, therefore, it is a base-catalyzed reaction.
The base used in the Schotten Baumann reaction also helps in neutralizing the hydrochloric acid which is formed during the process which protects the amide product formed from further protonation.
Instead of sodium hydroxide, pyridine can also be used as a base catalyst in the Schoten-Baumann reaction.
When pyridine is used as a base catalyst in the Schotten-Baumann reaction, the acyl chlorides get converted into superior power acylating agents.
3. What are the steps involved in the mechanism of the Schotten Baumann reaction?
The mechanism of the Schotten-Baumann reaction can be conveniently divided into three major steps. The first step involves the formation of a protonated compound by the reaction of amine and acyl chloride. The lone pair of electrons present on the nitrogen atom aid in the formation of a carbon-nitrogen bond thereby, neutralizing the positive and negative charges in the nitrogen and oxygen respectively by the exchange of portions between them. The second step of the reaction involves the formation of the double bond of oxygen with the carbonyl carbon, thereby liberating an acidic proton which is absorbed by the base catalyst of the reaction. The final step of the Schotten-Baumann reaction involves the formation of amide and hydrochloric acid which is also neutralized by the base catalyst present in the reaction.
4. Where is the Schotten-Baumann reaction used?
The Schotten-Baumann reaction has some extremely important applications in the field of chemistry. The few examples where the Schotten-Baumann reaction can be used are in the synthesis of synthetic phenethylamine and capsaicin, with the aid of acetic anhydride and acetyl chloride the reaction can be used for the acylation of benzylamines. Certain concepts of the Schotten-Baumann reaction are also used for the synthesis of peptides. Apart from these, the Schotten Baumann reaction has many more applications and the reaction and its conditions can be used for the synthesis of various chemicals and compounds in the laboratory.
5. Why is a base catalyst required in the process of the Schotten-Baumann reaction? Also, give examples of base catalysts used.
The Schotten-Baumann reaction is a condensation reaction of organic chemistry that synthesizes amides from acid chlorides and amines. The Schotten-Baumann reaction is carried out in the presence of a base catalyst. The presence of a base catalyst is very essential for the conduction of the complete mechanism of the Schotten-Baumann reaction because a base catalyst will shift the equilibrium of the reaction towards the formation of amides and it will also help in neutralizing the hydrochloric acid which is formed during the reaction. The neutralization of hydrochloric acid protects the amide product formed from further protonation. The popularly used base catalysts for the Schotten-Baumann reaction are pyridine and the aqueous solution of sodium hydroxide.
6. What are the important points to remember about the Schotten-Baumann reaction?
The most important point about Schotten-Baumann's reaction that every student should remember are:
The Schotten-Baumann reaction of benzoylation of phenols is a very important reaction method in the field of organic chemistry.
The Schotten-Baumann reaction is named after the scientists who discovered the reaction, namely Carl Schotten and Eugen Baumann, they were both chemists from Germany.
The reaction is mainly used in the field of organic chemistry for the benzoylation of phenols with benzoyl chloride.
The base catalysts that are used in the Schotten-Bauman reaction, to keep the medium of the reaction basic, are sodium hydroxide and pyridine because the reactants involved in the reaction are always acidic.
The phenol and the base involved in the reaction condition react to give phenoxide ion. Afterward, the benzoyl chloride is attacked by a phenoxide ion.
The negative charge prevalent in the reaction shifts to the oxygen molecule present in benzoyl chloride. The negative charge is then utilized to form a double bond between the oxygen atom and the carbon atom.
Since the carbon atom has the capability of forming only four bonds, the bond present between the carbon atom and the chlorine atom has to break. This bond breaks easily because of the electronegativity difference between the two atoms and the polar nature of the bond. This finally results in the formation of the final product, that is, phenyl benzoate.
The conditions of the Schotten-Baumann reaction make it easy to perform benzoylation of phenols.
The same condition of Schotten-Baumann can also be used for carrying out benzoylation of aromatic amines, synthesizing amides from acid chlorides and amines wherein acyl chlorides are reacted with amines to produce amides.
Apart from the stated above, the reaction can also be used in the synthesis of various compounds and chemicals in the laboratory.