fractional distillation oral report

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Fractional Distillation

Submitted by: Co, Vian Paolo V. Comendador, Mikaela V. Cruz, Patricia Ann A. De Jesus, Cara Gabrielle A.

What is Fractional Distillation?

Fractional Distillation is a type of distillation that involves separation of a mixture into its constituents based on the differences in their boiling point (volatility). It is practiced for those mixtures, in which the boiling point of the components differ by less than 25 C at one atmospheric pressure.

The component with the least boiling point is separated first, while the component with the highest boiling point is drawn off at the last. If the boiling point of the constituents differ by more than 25 C, then simple distillation procedure is implemented for separation.

How does Fractional Distillation Work?

In the process of fractional distillation, a specific apparatus is used for boiling the mixture and collecting a series of fractions of the constituent substances.

The laboratory setup for fractional distillation includes a round-bottom boiling flask, condenser, adapter (that connects boiling flask and condenser), fractionating column (within the adapter) and a collection flask. A thermometer is fixed to the adapter for monitoring the temperature.

The fractionating column is usually composed of plates arranged in a horizontal manner, which enhances the separation by allowing condensation, evaporation and recondensation of the separated components.

The vapor of the component substance after passing the fractionating column is passed to the condenser, which is fixed with a water inlet and water outlet pipe. In the water inlet pipe, cold water is constantly supplied to cool down or condense the separated vapor.

Eventually, warm water after being circulated through the condenser is removed via the outlet pipe. The component undergoes condensation in the condenser, which is then collected in the collection flask as a purified liquid.

The constituents with lower boiling point tend to collect at the top portion of the fractionating column, while those with higher boiling point settle at the bottom of the column

Though this type of distillation provides better separation of constituents, it requires more energy and longer time than the usual simple distillation.

What are the uses of fractional distillation?

Fractional Distillation is practiced in large-scale alcoholic fermentation in order to purify alcoholic beverages.

Beer and wine produced after fermentation of grains and grapes contain less than 15 percent alcohol. It is due to the fact that a high concentration of alcohol kills the yeast that are responsible for proceeding fermentation. In such a condition, fractional distillation is practiced to purify alcohol and make stronger alcoholic drinks. In addition, fractional distillation is also used for solvent recycling, extraction of essential oils and purification of fragrances in perfume industries.

Another use of fractional distillation is in the separation of impurities contained in crude oil. In fact, fractional distillation is the most common procedure followed for separation of mixtures in petroleum refining industries and chemical industries. In petroleum refining, gasoline is separated first followed by kerosene, heating oil and lubricating oil. This technology implemented in industries is referred to as continuous fractional distillation.

Difference of Fractional from simple distillation:

fractional distillation and simple distillation

are based on the same principle, but differ in procedure.

When the substances in a mixture have boiling points which differ largely, simple distillation is the first choice.

When that isn't the case, fractional distillation is used. This process uses a fractionating column, while simple distillation doesn't.

Simple distillation cannot guarantee high purity of the separated component but

fractional distillation can provide separated chemicals with a high degree of purity.

fractional distillation is used in separating mixtures whose components have boiling points that are too close to each other, while

simple distillation is used in case of mixtures whose components have boiling points that are substantially far apart.

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