DISTILLATION

Distillation Simple laboratory distillation Industrial distillation Fermentation and distillation

Distillation How would you separate the yellow liquid from the green mixture?

Distillation Yellow bp = 100oC Blue bp = 80oC Green bp = 100oC How do we get to Blue liquid out of the Green mixture?

Distillation Distillation can separate one liquid from another in a mixture solution Distillation works by evaporating one of the liquids from the solution It is then cooled and condensed into a separate container The other liquid is left behind

Distillation

Distillation Distillation is used to purify a compound by separating it from a non-volatile or less-volatile material When different compounds in a mixture have different boiling points they can be separated into individual components by distillation

Distillation Where is distillation used? Distillation is used to separate crude oil into specific fractions, such as petrol or kerosene Water is distilled to remove impurities (e.g. salt from seawater) Air is distilled to separate it into O2 and N2 Distillation of fermented solutions has been used since ancient times to produce beverages with a high alcohol content

Distillation Distillation is a method of separating mixtures based on differences in their boiling points Distillation is a physical separation process and not a chemical reaction

Simple Laboratory distillation apparatus

Simple laboratory distillation apparatus

Distillation Boiling points are measured by recording the temperature (within a specific range) on a thermometer while performing a distillation The distillation method of boiling point determination measures the temperature of the vapours above the liquid These vapours are in equilibrium with the boiling liquid and are the same temperature as the boiling liquid

Distillation The boiling point: temperature at which the vapour pressure of the liquid phase of a solution equals the external (atmospheric) pressure acting on the surface of the liquid The vapour pressure: is an indication of a liquid's evaporation rate. It relates to the tendency of particles to escape from the liquid A substance with a high vapour pressure at normal temperatures is referred to as volatile

Distillation The vapour pressure of the liquid will increase as the temperature of the liquid increases These vapours are in equilibrium with the boiling liquid and are the same temperature as the boiling liquid When the vapour pressure equals the atmospheric pressure the liquid will boil

Distillation Different compounds boil at different temperatures because each has a different, characteristic, vapour pressure Compounds with higher vapour pressures will boil at lower temperatures (i.e. first to distil)

Industrial Distillation

Distillation Large scale industrial distillation applications are required for: petroleum refineries petrochemical and chemical plants natural gas processing plants

Distillation Industrial distillation is performed in large, vertical, cylindrical columns known as distillation towers or distillation columns Diameters: 65 cm ~16 m Heights: 6 m ~ 90 m or more

Distillation

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Distillation Industrial towers use reflux to separate products Reflux: down flowing liquid provides cooling and condensation of the up flowing vapours Fractions collected at specific parts of the tower The more reflux that is provided the better the tower's separation of lower boiling materials from higher boiling materials

Fraction: a group of compounds with boiling points & carbon chains within a given range http://www.schoolscience.co.uk/content/4/chemistry/fossils/p7.html

Distillation Fractionating columns use trays to help separate the mixture by allowing the mixed vapors to cool, condense, and vaporize again With each condensation-vaporization cycle the vapors are enriched in a certain component A larger surface area allows more cycles, improving separation.

Distillation When the process feed has a diverse composition (e.g. crude oil) outlets at intervals up the column allow for the withdrawal of different fractions collected on trays having different carbon chain lengths and boiling ranges

Distillation The lightest products (lowest boiling point) exit from the top of the column The heaviest products (highest boiling point) exit from the bottom of the column

Fermentation and distillation

Distillation Ethanol fermentation is a biological process in which sugars such as glucose, fructose, or sucrose are converted into cellular energy The metabolic waste produce are ethanol and carbon dioxide Yeasts perform this conversion in the absence of oxygen: ethanol fermentation is anaerobic Ethanol fermentation occurs in the production of alcoholic drinks, biofuel, and bread

Distillation A distilled beverage, liquor, or spirit is an alcoholic beverage containing ethanol (CH3CH2OH) Produced by distilling (i.e. concentrating by distillation) ethanol produced by means of fermenting grain, fruit, or vegetables

Distillation A still is a apparatus used to distill miscible or immiscible liquid mixtures by heating to selectively boil and then cooling to condense the vapor Stills are used to produce beverages containing ethanol (CH3CH2OH)

Fermentation and distillation

Distillation Conclusion Distillation is a process of physically separating mixtures Difference in vapour pressure and boiling point Used in the laboratory, industry, and in the fermentation process

Questions What are the similarities and differences between the 3 methods of distillation? Why is temperature range related to purity? Would a mixture distil quicker or slower in a vacuum? 4. Design an experiment to separate 3 liquids from a mixture