AIM : To carry out the bromination of given organic compound.
MATERIAL REQUIRED : Given compound ,bromine solution(bromine in acetic acid),conical flask,test tube,measuring cylinder,filter paper,funnel,beaker.
THEORY:
Bromination is a chemical reaction that introduces one or more bromine atoms (Br) into a molecule. It is a type of halogenation reaction where bromine (br2) acts as the halogenating agent. Often used to modify the chemical properties of organic compounds, such as increasing reactivity, altering physical properties, or preparing intermediates for further reactions.
Aniline's amino group (NH2) is a strong activator for the benzene ring, making it react rapidly with bromine. This can lead to over-bromination if you're not careful. By default, aniline will react with bromine water even at room temperature, producing 2,4,6-tribromoaniline.
Bromination of Aniline:
When aniline (C6H5NH2) undergoes bromination, the amino group (NH2) activates the benzene ring, making it highly reactive toward bromine. This can lead to the formation of 2,4,6-tribromoaniline if the reaction is not controlled.
Understanding Bromination of Aniline:
The amino group (NH2) in aniline is an electron-donating group, which strongly activates the benzene ring. This activation makes the ortho and para positions on the benzene ring highly reactive toward electrophiles like bromine. If bromine is added directly to aniline, it reacts rapidly and often leads to over-bromination, producing 2,4,6-tribromoaniline.
The reaction can be summarized as:
C6H5NH2 +CH3COOH+ 3Br2 → C6H2Br3NH2 + 3HBr
PROCEDURE:
took 1 ml of given compound in dried conical flask.
took 1-2 ml glacial acetic acid in the beaker.
also took 5-7ml of bromine solution in the test tube.
added bromine solution in the beaker drop by drop.
while adding continuously stirred by glass rod.
done it until get yellow permanent ppt in the beaker.
Transferred whole content of beaker in glass of cold water so as extra bromine get separate.
filtered it using filter paper and funnel.
OBSERVATION:
1.yellow permanent ppt form in the solution in flask when complete bromination occurs.
2.when pour it in glass of cold water a white ppt form.
RESULT:
1.the white color ppt formed i.e. 2,4,6-tribromoaniline indicates the bromination of aniline has taken place
PRECAUTIONS:
When brominating a given compound, it's essential to take several precautions to ensure the reaction proceeds smoothly and safely. The exact precautions will depend on the nature of the compound being brominated, but here are general guidelines to follow:
1. Understand the Reactivity of the Compound:
Ensure you know the chemical structure and functional groups of the compound. The reactivity of the compound will determine the conditions needed for bromination (e.g., temperature, solvent, catalysts).
Certain compounds, like aromatic rings or alkenes, undergo electrophilic substitution or addition reactions with bromine, respectively. Ensure you're familiar with how your specific compound will react.
2. Use Appropriate Solvents:
Choose a solvent that is inert and appropriate for the bromination reaction. Common solvents include carbon tetrachloride (CCl₄), dichloromethane (DCM), or acetic acid, depending on the system.
Avoid using flammable solvents in the presence of bromine gas, as bromine is corrosive and potentially hazardous.
3. Handle Bromine with Care:
Bromine is a highly reactive and toxic substance. It is a strong oxidizing agent and can cause severe burns on contact with skin.
Always use bromine in a well-ventilated fume hood to avoid inhaling its toxic vapors.
Wear protective gloves, goggles, and a lab coat to protect yourself from exposure.
Ensure that you have a spill kit on hand in case of bromine spills.
4. Temperature Control:
The reaction may need to be carried out at a specific temperature to control the rate of bromination. For some reactions, cooling (e.g., in an ice bath) may be necessary, particularly to prevent over-bromination or unwanted side reactions.
If you're using bromine gas (for aromatic bromination, for example), it may be best to perform the reaction under cold conditions to control the reaction's rate and prevent excessive reaction.
5. Monitor the Reaction:
Keep an eye on the reaction to avoid over-bromination. Over-bromination can lead to the formation of unwanted side products.
Consider using TLC (thin-layer chromatography) or UV-Vis spectroscopy to monitor the reaction progress.