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DISTILLATION LAB #2 . Background of Distillation . - Distillation is a process of boiling a liquid and condensing and collecting the vapor. -The liquid collected is the distillate. -The usual purpose of distillation is purification or separation of the components of a mixture. .
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Background of Distillation • -Distillation is a process of boiling a liquid and condensing and collecting the vapor. • -The liquid collected is the distillate. • -The usual purpose of distillation is purification or separation of the components of a mixture.
Background of Distillation • -This is possible because the composition of the vapor is usually different from that of liquid mixture from which it is obtained. • -It is a physical separation process, not a chemical reaction.
Application of Distillation • -Laboratory scale distillation. • -Industrial distillation. • -Herbal distillate. • -Food processing
Laboratory Scale Distillation • -Simple distillation. • -Fractional distillation. • -Steam distillation. • -Other types.
Simple Distillation , cont. • -Simple distillation is a procedure by which two liquids with different boiling points can be separated. • -It can be used effectively to separate liquids that have at least fifty degrees difference in their boiling points. • -The vapors that form will be richest in the component of the mixture that boils at the lowest temperature.
Simple Distillation, cont. • As distillation progresses, the concentration of the lowest boiling component will steadily decrease. • Eventually the temperature within the apparatus will begin to change; a pure compound is no longer being distilled. The temperature will continue to increase until the boiling point of the next-lowest-boiling compound is approached. • When the temperature again stabilizes, another pure fraction of the distillate can be collected.
Simple Distillation, cont. Figure 3. The thermometer is inserted in the distillation flask through a hole in the cork stopper. The arm of the flask is inserted through a hole in the stopper of the condenser. Make sure these stoppers are airtight, or the vapor will escape Figure 1. Distillation apparatus. A distillation flask with a thermometer is placed in a heating mantle and is connected to a condenser. Figure 2. The tubes on the condenser are attached to a water source, with the water flowing in the low end and flowing out the high end of the condenser. The condensed vapor drips into the collection receiver.
Simple Distillation, cont. Figure 4. The distillation flask being heated in a heating mantle. Figure 5. The collection receiver The vapors condense and drip from the condenser into the flask
Fractional Distillation, cont. • It used to separate liquids with similar boiling points. • The procedure and apparatus of fractional distillation are so similar to those involved in simple distillation.
Fractional Distillation, cont. • -The only difference between the equipment used in fractional distillation and that used in simple distillation is that with fractional distillation, a packed fractionating column is attached to the top of the distillation flask and beneath the condenser. • -This will make the vapor condenses and revaporized many times. • -At each stage of condensation\ revaporization, the vapor is further enriched in the lower boiling component.
Steam Distillation • -Steam distillation is a special type of distillation for temperature sensitive material. • -It is useful for the isolation of volatile organic compounds, such as essential oils from plant material.
