Lab 4: Distillation PDF

Lab. 4 / Distillation Pharmacist : Muthanna Taha  Distillation Distillation is method of separation of components from a liquid mixture which depends on the differences in boiling points of the individual components and the distributions of the components...

Lab. 4 / Distillation Pharmacist : Muthanna Taha  Distillation Distillation is method of separation of components from a liquid mixture which depends on the differences in boiling points of the individual components and the distributions of the components between a liquid and gas phase in the mixture, or is a process of purification of liquid organic compounds by conversion to the vapor state with the aid of heat, and condensation of the vapors to the liquid state..  AIM OF DISTILLATION 1. Purification of liquid organic substances. 2. Determination of the boiling point. 3. Separation of liquid organic substances from each other or from a solid compound. TYPES OF DISTILLATION There are four types of distillation: Simple distillation Vacuum distillation Steam distillation Fractional distillation 1. Simple distillation: This method is used for the separation of liquids having boiling points ranging from 30 °C to 150 °C and is stable to heat. 2. Vacuum distillation (Distillation under reduced pressure): This method is used for the separation of liquids with high boiling points or is unstable to heat. These difficulties may be overcome by lowering the pressure over the substance, thus lowering the boiling point. 3. Steam distillation: This method is used for the separation of water immiscible compound of low volatility from non- volatile tarry products which are formed as by-products in many reactions. 4. Fractional Distillation: It is used to separate mixtures in which the components have boiling points that differ by only a few degrees, by employing a fractionating column in the distillation apparatus. or fractional distillation is a process of collecting separate fractions according to controlled boiling ranges during the distillation of a mixture of substances. Name of experiment: Simple Distillation Aim of experiment: Purification of Ethanol Procedure: 1- Put 100 ml of ethanol in a boiling flask. 2- Add 2-3 pieces of boiling chips. 3- Start the water running slowly through the condenser. 4- Heat until boiling. 5- Adjust the temperature so that distillation proceeds at 2-3 drops per second. Discard the first 2-3 ml of the distillate. 6- Continue distillation until you collect 30-60 ml. 7- Record the boiling point of your liquid, Ethanol.  Azeotropic mixture: Azeotropic mixture : is a mixture of two or more liquids a constant boiling in which the proportions of liquids cannot be altered by simple distillation. This happens because when an azeotrope is boiled, the vapor pressure has the same proportions of constituents as the un boiled mixture. Example: 95% Ethyl alcohol & 5% water produce an Azeotropic mixture, which boils at 78.15 ⁰C.