🎀 Distillation 🎀 ORGCHEM

• Simple distillation


  Used in the separation of a volatile liquid from a nonvolatile substance
• Types of distillation

  • Simple
  • Fractional
  • Steam
• Distillation

  Laboratory technique employed to separate homogeneous mixture containing 2 or more liquids with different boiling points
• There are several types of distillation
• Distillation

  Liquid organic compound is converted to the vapor state at its boiling point and subsequently condensed back to the liquid state upon cooling
• Fractional distillation


  Used to separate a mixture of miscible liquids that are volatile and with boiling points that are near each other
• Steam distillation

  Used in the separation of an organic compound from a solid material using water in the form of steam
• The material to be distilled should be immiscible with water which can be readily separated from the water once distillation is complete
• APPARATUS

  Condenser, distilling flask, adapter, clamps, burner, iron stand, Erlenmeyer flask, funnel, graduated cylinder, water trough, 600 mL beaker, thermometer
• REAGENTS and MATERIALS

  • Ethyl alcohol
  • corks and rubber stoppers
  • boiling chips
• SAFETY PRECAUTION

  1. Proper assembly of the distillation apparatus is important in order to avoid possible breakage and to avoid the release of distillate vapors into the room. Make sure that all connections in the apparatus are tight before beginning the distillation. Have your instructor inspect your set-up after it is assembled.

  2. Since it is necessary to use burners, exercise great care: ethyl alcohol is highly flammable. Place distillates away from the flame.
• PROCEDURE

  Simple Distillation

  1. Wear protective glasses.

  2. Prepare a simple distillation set-up (Figure 2, page 15) and have it

  checked by your instructor.

  Prepare a 50 mL mixture consisting of 25 mL ethyl alcohol and 25 mL

  of water. Smell the mixture_______

  3. Pour the mixture into the distilling flask using a funnel and then add two small pieces of boiling chips. Heat the sample using a low flame initially then gradually increase the flame.
• Distillation procedure

  1. Start recording at 0 min. Record at 1-minute intervals until only about 10 mL of the mixture remains
• process

  
• Consequences of superheating include uncontrolled boiling and the formation of bubbles
• A too rigidly clamped distillation apparatus can lead to breakage due to pressure build-up
• Advantages of simple distillation over other types of distillation include its simplicity, low cost, and ease of use
• Steam distillation is used to separate heat-sensitive substances, such as essential oils, and is commonly used in the perfume industry
• If the bulb of the thermometer is placed below the adapter sidearm, the observed temperature reading will be higher than the actual temperature
• Fractional distillation is used to separate mixtures with closely boiling components, such as ethanol and water, and is commonly used in the petroleum industry to separate crude oil into different fractions
• A very rapid rate of distillation can lead to a decrease in the purity of the distilled liquid due to the entrainment of impurities
• Superheating of the vapor during simple distillation should be avoided
• If the bulb of the thermometer is placed above the adapter sidearm, the observed temperature reading will be lower than the actual temperature
• An effective way of preventing irregular ebullition or bumping of the mixture during distillation is to cool the base of the distillation flask
• 8. Plot temperature vs. time

  Draw a distillation curve
• 2. Prepare a simple distillation set-up (Figure 2, page 15) and have it

  checked by your instructor.

  Prepare a 50 mL mixture consisting of 25 mL ethyl alcohol and 25 mL

  of water. Smell the mixture_______
• 3. Pour the mixture into the distilling flask using a funnel and then add two small pieces of boiling chips. Heat the sample using a low flame initially then gradually increase the flame.
• 4. When the temperature reaches 50°C start recording at 0 min. Record at 1-minute intervals until only about 10 mL of the mixture remains.
• 5. Prepare 3 flasks labeled 1,2 and 3. Use flask 1 to collect the first distillate. When the temperature reaches 81°C, replace flask 1 with flask 2 and cover flask 1 with a stopper.
• 6. Continue the distillation up to 95°C. At this point, replace flask 2 with

  flask 3 and cover flask 2 with a stopper.
• 7. When only a small amount of the mixture remains, ask your instructor if you can already terminate distillation. Cover flask 3 with a stopper. 
• 8. Plot temperature vs. time and draw a distillation curve.
• 9. Note the smell of the distillates in flasks 1 to 3.
• 10. Pour a small amount of each of the three distillates in separate evaporating dishes and test the flammability with a lighted splinter. Remove flammable materials from the table while doing this step.
• 11. Dismantle your distillation set-up. Smell the mixture remaining in the flask and measure the volume.
• 12. Empty the contents of the flask into the sink and flush the mixture with water. Throw boiling chips into the wastebasket. Clean and rinse your glasswares.
• simple distillation separates a liquid from a solid impurity
• simple distillation separates a large boiling point difference
• fractional distillation is miscible liquids with small boiling points difference
• steam distillation is used for separating volatile organic compounds which are water immiscible