Content Writer
The Gabriel Phthalimide Synthesis reaction is used to produce primary amines from primary alkyl halides. This reaction was identified by Siegmund Gabriel. Gabriel Phthalimide Synthesis reaction can only be carried out with the primary alkyl halides. It doesn’t work with secondary alkyl halides. Let’s understand more about Gabriel Phthalimide Synthesis reaction, mechanism of Gabriel Phthalimide Synthesis reaction and its limitations.
| Table of Content |
Key Terms: Gabriel Phthalimide, Reactions, primary alkyl, Amines. phthalimide, nucleophile, amide, ammonia, alkyl halides, Phthalic acid
Gabriel Phthalimide Synthesis
[Click Here for Sample Questions]
The Gabriel Phthalimide synthesis reaction is named after Siegmund Gabriel, a German scientist. The Gabriel Phthalimide synthesis reaction transforms primary alkyl halides for the production of primary amines. There is a use of phthalimide to prepare primary Amide.
Phthalic acid is reacted with ammonia in the presence of heat for the production of phthalimide.
Also Read:
| Related Articles | ||
|---|---|---|
| Physical Properties of Amines | Sandmeyer reaction | Gatterman reaction |
| Hofmann Elimination | Hinsberg’s Reagent | Electrophilic Substitution |
| Sulphonation | Diazotisation | Group 15 Elements |
Gabriel Phthalimide Synthesis Reaction
[Click Here for Sample Questions]
Gabriel Phthalimide Synthesis Reaction
Gabriel Phthalimide Synthesis Reaction Mechanism
[Click Here for Sample Questions]
Gabriel Phthalimide Synthesis reaction is a 3 step mechanism for the production of primary amide. It used primary alkyl halides to prepare primary amines. It employs the use of a basic hydroxide and phthalimide. The basic hydroxide can be sodium hydroxide or potassium hydroxide.
Steps:-
Step 1: Phthalimide and potassium hydroxide are mixed in a beaker. The hydroxide ion dehydrogenates the imide. The proton produced is more acidic as compared to the simple amine due to the presence and resonance of two carbonyl-like groups. This leads to the generation of a strong nucleophile.
Step 2: In the second step, the formation of an N-Alkyl Phthalimide takes place. The electrophilic carbon in the alkyl halide is attacked by the nucleophilic imide ion. The halogen in the alkyl halide is replaced by the nitrogen atom. The nitrogen atom bonds with the carbon atom and this results in the production of N-Alkyl Phthalimide.
Step 3: The nitrogen atom attaches itself to the R group. This step is similar to base-catalyzed hydrolysis of esters, the only difference being that the bond formed is between the R group and nitrogen instead of oxygen and nitrogen. The carbon atom is attacked by the hydroxide ion of potassium hydroxide. The N-alkyl phthalimide splits.
Limitations of Gabriel Phthalimide Synthesis
[Click Here for Sample Questions]
- The Gabriel Phthalimide Synthesis reaction can only be used for the formation of primary alkyl amine.
- It cannot be used to form secondary or tertiary amine.
- Gabriel Phthalimide Synthesis reaction cannot be used for the formation of aryl amine.
Things to Remember
- The Gabriel Phthalimide synthesis reaction is used to produce primary amines.
- In Gabriel Phthalimide Synthesis redaction, primary alkyl halides are used for the production of primary amines. Phthalimide is also used to prepare primary amide.
- When Phthalimide and potassium hydroxide are mixed, the hydroxide ion dehydrogenates the imide. This leads to the generation of a strong nucleophile.
- The electrophilic carbon in the alkyl halide is attacked by the nucleophilic imide ion.
- The halogen in the alkyl halide is replaced by the nitrogen atom. The nitrogen atom bonds with the carbon atom and this results in the production of N-Alkyl Phthalimide.
- The nitrogen atom attaches itself to the R group and the carbon atom is attacked by the hydroxide ion of potassium hydroxide.
- At last, the N-alkyl phthalimide splits.
Also Read:
| Related Articles | ||
|---|---|---|
| Nitro Compounds | Carbonyl Compounds | Azo Compound |
| Etard reaction | Redox Reactions | Finkelstein reaction |
Sample Questions
Ques: How is Phthalimide produced for Gabriel Phthalimide Synthesis Reaction? (1 Mark)
Ans: Phthalimide is produced for the reaction by using phthalic acid. Phthalic acid, when made to react with ammonia, produces phthalimide.
Ques: Which of the following is not a method for preparation of amines: (1 Mark)
a) Reduction of amides
b) Hoffmann bromamide degradation reaction
c) Coupling reaction
d) Gabriel phthalimide synthesis
Ans: c) Coupling Reaction
Ques: What is diazotization? (1 Mark)
Ans: When reacting with nitrous acid at a low temperature, aromatic primary amines form diazonium salts. Diazotization is this process of converting aromatic primary amines into diazonium salts.
Ques: Why is a basic hydroxide used for Gabriel Phthalimide Synthesis Reaction? (1 Mark)
Ans: Gabriel Phthalimide Synthesis Reaction can be carried out by using hydrazine or acidic hydrolysis instead of a basic hydroxide. But both of them have many disadvantages. During the use of hydrazine, circumstances can turn severe. So, hydrazine or acidic hydrolysis are avoided and basic hydroxide is used for the reaction.
Ques: Specify the IUPAC names for the following compounds and mention their amines (primary, secondary or tertiary): (3 Mark)
1) ( CH3 CH2 )2 N CH3
2) m – Br C6 H4 NH2
3) CH3 NH CH ( CH3 )2
Ans:
- N – Ethyl – N – methyl ethanamine (tertiary amine )
- 3 – Bromobenzenamine or 3 – bromoaniline (primary amine )
- N – Methyl – 2 – methyl ethanamine (Secondary amine)
Ques: How can one identify primary, secondary and tertiary amines? (4 Marks)
Ans: The identification of primary, secondary and tertiary amines can be done using the Hinsberg’s test. The amines are made to react with benzene sulphonyl chloride, a Hinsberg’s reagent. All the amines have different reactions when they come in contact with Hinsberg’s reagent.
Primary amines react with the reagent to produce N-alkyl benzene sulphonyl amide.
Secondary amines react with the reagent to produce sulphonamide.
Tertiary amines don’t react with Hinsberg’s reagent.
Ques: How can one differentiate between the following pairs of compounds? Give the names of chemical tests that can be used. (4 Marks)
1. Aniline and benzylamine
2. Secondary and tertiary amines
3. Methylamine and dimethylamine
4. Ethylamine and aniline
5. Aniline and N-methylaniline.
Ans: The pairs of compounds mentioned above can be differentiated using the following chemical tests:
- Aniline and benzylamine: reaction with nitrous acid,
- Secondary and tertiary amines: reaction with Hinsberg’s reagent
- Methylamine and dimethylamine: carbylamine test.
- Ethylamine and aniline: azo – dye test
- Aniline and N-methylaniline: Carbylamine test
Ques: Explain the Gabriel Phthalimide Synthesis Reaction Mechanism. (4 Marks)
Ans: In the first step, Phthalimide and potassium hydroxide are mixed and made to react. The hydroxide ion deprotonates the imide. The proton produced is more acidic compared to the simple amine due to the presence of two carbonyl-like groups. This leads to the generation of a strong nucleophile.
In the second step, The electrophilic carbon in the alkyl halide is attacked by the nucleophilic imide ion. The halogen in the alkyl halide is replaced by the nitrogen atom. The nitrogen atom bonds with the carbon atom and this results in the production of N-Alkyl Phthalimide.
In the third and last step, The nitrogen atom attaches itself to the R group. This step is similar to base-catalyzed hydrolysis of esters, the only difference being that the bond formed is between R group and nitrogen instead of oxygen and nitrogen. The carbon atom is attacked by the hydroxide ion of potassium hydroxide. The N-alkyl phthalimide splits.
For Latest Updates on Upcoming Board Exams, Click Here: https://t.me/class_10_12_board_updates
Check-Out:
Comments