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Separation of Hexane and Toluene By simple distillation
To perform a simple distillation, follow these summarized steps for setting up the apparatus and conducting the distillation:
1. Set Up the Apparatus:
- Start with a burner and place an iron ring and wire gauze about 4-5 cm above the burner.
- Position a 100-mL beaker on the wire gauze.
- Clamp a 100-mL pear-shaped or round-bottom flask to an iron stand, protecting the neck with tissue paper.
2. Assemble the Distillation Unit:
- If using a semi-microscale setup, attach the one-piece distillation unit (air column, distilling head, thermometer holder, condenser, and receiver) by applying a thin film of grease to the male joint and connecting it to the female joint of the flask. Avoid excess grease to prevent contamination.
3. Connect the Condenser:
- Ensure the delivery tubes of the condenser are connected properly: the water inlet should be near the receiver and the outlet near the Claisen head for effective cooling.
- Support the condenser with a utility clamp and pad it with tissue paper.
4. Prepare Thermometer:
- Place a few drops of oil at the thermometer holder, then insert the thermometer.
5. Check the Setup:
- Ensure all connections are secure. Circulate a slow stream of water through the condenser. Use a clean, dry 10-mL graduated cylinder to collect the first few milliliters to discard (forerun). Have your instructor check the setup.
6. Add Samples:
- Add 30 mL of n-hexane and 30 mL of toluene to the round-bottom flask, ensuring it is outside the setup to avoid spills.
7. Begin Distillation:
- Bring the mixture to a boil. Once liquid begins to drop into the receiver, adjust the heat to achieve a steady drip rate of about one drop per second.
- Discard the first 1 mL of distillate and record the temperature for each 1 mL fraction collected until 20 mL of distillate is obtained. Group distillates with the same boiling point into a test tube.
8. Complete the Distillation:
- When distillation is complete, turn off the burner and lower the oil bath. Never allow the distilling flask to dry out, and do not stop the water circulation until the apparatus cools down.
Summary: This procedure involves setting up a simple distillation apparatus, adding a mixture of n-hexane and toluene, and carefully controlling the distillation process while recording temperatures and managing the collected distillate. Always ensure safety and proper cooling.
Separation of Hexane and Toluene By Fractional Distillation
1. Apparatus Arrangement:
- Use a 100-mL beaker on top of wire gauze.
- Clamp a 100-mL pear-shaped or round-bottom flask to an iron stand, protecting the neck with tissue paper.
2. Assemble the Distillation Unit:
- If using a semi-microscale setup, attach the one-piece assembly that includes the fractional column, Claisen head, thermometer holder, condenser, and receiver.
- Apply a thin film of grease to the male joint and connect it to the female joint of the flask. Avoid excess grease to prevent sample contamination.
3. Connect the Condenser:
- Ensure the condenser’s delivery tubes are correctly attached: the water inlet should be near the receiving end and the outlet near the Claisen head for optimal cooling.
- Support the condenser with a utility clamp and pad it with tissue paper.
4. Prepare the Thermometer:
- Add a few drops of oil to the thermometer holder and insert the thermometer.
5. Check Setup:
- Ensure all connections are secure and have a slow stream of water circulating through the condenser.
- Use a clean, dry 10-mL graduated cylinder to collect the first few milliliters for discarding (forerun). Have your instructor check the setup.
Distillation Process
6. Add Sample:
- Add 30 mL of n-hexane and 30 mL of toluene to the round-bottom flask, ensuring the flask is not in the setup to avoid spills.
7. Boil the Mixture:
- Heat the mixture until it begins to boil. Once liquid starts dropping into the receiver, adjust the heat to achieve a steady drip rate of about one drop per second.
8. Collect Distillate:
- Discard the first 1 mL of distillate and record the temperature for each 1 mL fraction collected until 20 mL of distillate is obtained. Group distillates with the same boiling point in a test tube.
9. Finish Distillation:
- When distillation is complete, turn off the burner and lower the oil bath. Never allow the distilling flask to dry out, and do not stop the water circulation until the apparatus has cooled.
Comparison With Simple Distillation
Fractional vs. Simple Distillation:
- Fractional distillation uses a fractional column to separate mixtures with closer boiling points more effectively, allowing for better separation and collection of fractions.
- Simple distillation is suitable for separating components with significantly different boiling points but is less effective when the boiling points are close.
Summary: This procedure involves setting up a fractional distillation apparatus, boiling a mixture of n-hexane and toluene, collecting distillate while monitoring temperature, and comparing the effectiveness of fractional versus simple distillation for separation.
