Distillation Methods
Distillation is a process that separates the
constituents of a mixture. The process is used to
fraction crude oil into its various components, each
of which has specific uses. Water distillation is used
to separate impurities from saline water to make it
fit for agricultural and drinking purposes. Air
distillation separates the components of air, including
nitrogen, oxygen and argon, which are then used for
different industrial applications. Molecular,
fractional, steam, regular, vacuum, extractive,
azeotropic (1), are the most common distillation
methods.
temperature sensitive liquids can be effectively
separated without degradation. The petroleum
refining industry uses this distillation to separate
the compounds of crude oil.
5. When separation is very difficult because the
components of a mixture have almost identical
volatilities, improvement can be made by adding a
different component which is soluble in the
mixture or which forms a constant boiling or
azeotropic mixture with one or more of the original
ingredients, thus permitting greater ease of
separation. An example of this is the addition of
benzene to an ethyl alcohol-water mixture in order
to produce pure anhydrous ethyl alcohol.
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1. This process is typically used to separate
liquids whose boiling points differ by at least 77
degrees Fahrenheit, and to separate liquids from oils
or non-volatile solids. In this process, a mixture is
heated at a high temperature to produce vapors,
which are then cooled, condensed and collected in a
separate container. This method is used in various
industries, including the medical and pharmaceutical
industries, to remove pathogens from water.
2. This is a process in which a mixture is split
into its constituents typically by repeatedly heating,
boiling and condensing. It is used to fraction miscible
liquids with different boiling points. In this method of
distillation, a mixture is heated and converted into
vapors, which are then cooled as they pass up a
fractionating column. Each component element of
the vapor converts back into a liquid at a different
level of the column. This distillation method is
typically used to separate the components of
unrefined petroleum.
3. This process is usually used to separate
materials that are temperature sensitive, such as
organic and aromatic compounds. Many such
compounds decompose at constant high
temperatures, making regular distillation
nonviable. It proves a more effective method, in
which steam or water is added to the mixture to
depress the boiling points of its constituent
elements. This allows them to evaporate at
temperatures lower than those at which they
deteriorate. It is typically used to separate organic
compounds from water and is widely used in
petrochemical plants and petrol refineries.
4. It is a process in which a vacuum is used to
extract or separate the components of a mixture at
a pressure that is lower than atmospheric pressure.
The lowered pressure reduces the boiling point of
the mixture, typically a liquid, and its liquid
components. At lowered pressure it ensures that
6. In this process, a solvent, which is usually less
volatile than any of the substances being separated,
is put in the downflowing liquid reflux stream near
the top of the column, and is removed from the
base. It modifies the vaporization characteristics of
the materials to enable them to be parted more
easily.
7. This high vacuum process furnishes the
lowest temperature believed possible. Unstable
substances which can be purified by no other
means of can often be treated without harm in the
molecular still. I. This process is used for making
vitamin A esters, as well as mono and diglycerides
of fatty acids which are used widely in the baking
and cosmetic industries.
By Natasha Gilani , eHow Contributor, updated:
September 4, 2010.
Glossary:
1.An azeotrope (pronounced /əozi.ətroʊp/ əZEE-ə-trope) is a mixture of two or more liquids in
such a ratio that its composition cannot be changed
by simple distillation.[1] This occurs because, when
an azeotrope is boiled, the resulting vapor has the
same ratio of constituents as the original mixture.
2.Volatitlity: a measure of the tendency of a
substance to vaporize. It has also been defined as a
measure of how readily a substance vaporizes.
3. reflux: technique involving the condensation of
vapors and the return of this condensate to the
system from which it originated.
Task 1
Define or find a synonym for the terms in bold.
Task 2
Name the distillation methods described in each
paragraph.