A report on Azeotrope

Vapour–liquid equilibrium of 2-propanol/water showing positive azeotropic behaviour.
Positive azeotrope – mixture of chloroform and methanol
Negative azeotrope – mixture of formic acid and water
Construction of the p-v-x diagram appropriate for an azeotrope
Phase diagram of a heteroazeotrope. Vertical axis is temperature, horizontal axis is composition. The dotted vertical line indicates the composition of the combined layers of the distillate whenever both layers are present in the original mixture.
Double azeotrope of benzene and hexafluorobenzene. Proportions are by weight.
Total vapor pressure of mixtures as a function of composition at a chosen constant temperature
Phase diagram of a positive azeotrope. Vertical axis is temperature, horizontal axis is composition.
Phase diagram of a negative azeotrope. Vertical axis is temperature, horizontal axis is composition.
Azeotrope composition shift due to pressure swing.
Saddle azeotropic system Methanol/Acetone/Chloroform calculated with mod. UNIFAC

Mixture of two or more liquids whose proportions cannot be altered or changed by simple distillation.

- Azeotrope
Vapour–liquid equilibrium of 2-propanol/water showing positive azeotropic behaviour.

15 related topics with Alpha

Overall

Schematic of a simple distillation setup.

Distillation

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Process of separating the components or substances from a liquid mixture by using selective boiling and condensation.

Process of separating the components or substances from a liquid mixture by using selective boiling and condensation.

Schematic of a simple distillation setup.
Distillation equipment used by the 3rd century alchemist Zosimos of Panopolis, from the Byzantine Greek manuscript Parisinus graces.
Hieronymus Brunschwig's Liber de arte Distillandi de Compositis (Strassburg, 1512) Science History Institute
A retort
Distillation
Old Ukrainian vodka still
Simple liqueur distillation in East Timor
A batch still showing the separation of A and B.
Dimethyl sulfoxide usually boils at 189°C. Under a vacuum, it distills off into the receiver at only 70°C.
Perkin triangle distillation setup
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 | Teflon tap 2
 | Vacuum/gas inlet
 | Teflon tap 3
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Short path vacuum distillation apparatus with vertical condenser (cold finger), to minimize the distillation path;
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 | Vacuum/gas inlet
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Typical industrial distillation towers
Diagram of a typical industrial distillation tower
Section of an industrial distillation tower showing detail of trays with bubble caps
Large-scale, industrial vacuum distillation column

These compounds, when heated together, form an azeotrope, which is when the vapor phase and liquid phase contain the same composition.

Fractional distillation

Fractional distillation

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Separation of a mixture into its component parts, or fractions.

Separation of a mixture into its component parts, or fractions.

Fractional distillation
Typical industrial fractional distillation columns
Diagram of a typical industrial distillation tower
Crude oil is separated into fractions by fractional distillation. The fractions at the top of the fractionating column have lower boiling points than the fractions at the bottom. All of the fractions are processed further in other refining units.
Chemical engineering schematic of typical bubble-cap trays in a distillation tower

Some mixtures form azeotropes, where the mixture boils at a lower temperature than either component.

USP grade ethanol for laboratory use.

Ethanol

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Organic chemical compound.

Organic chemical compound.

USP grade ethanol for laboratory use.
Ethanol burning with its spectrum depicted
Hydrogen bonding in solid ethanol at −186 °C
94% denatured ethanol sold in a bottle for household use
Infrared reflection spectra of liquid ethanol, showing the −OH band centered near 3300 cm−1 and C−H bands near 2950 cm−1
Near-infrared spectrum of liquid ethanol

Mixtures of ethanol and water form an azeotrope at about 89 mole-% ethanol and 11 mole-% water or a mixture of 95.6 percent ethanol by mass (or about 97% alcohol by volume) at normal pressure, which boils at 351K (78 °C).

Fuming nitric acid contaminated with yellow nitrogen dioxide

Nitric acid

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Inorganic compound with the formula HNO3.

Inorganic compound with the formula HNO3.

Fuming nitric acid contaminated with yellow nitrogen dioxide
Two major resonance representations of HNO3
Nitric acid in a laboratory

Commercially available nitric acid is an azeotrope with water at a concentration of 68% HNO3.

A diagram representing at the microscopic level the differences between homogeneous mixtures, heterogeneous mixtures, compounds, and elements

Mixture

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Material made up of two or more different chemical substances which are not chemically bonded.

Material made up of two or more different chemical substances which are not chemically bonded.

A diagram representing at the microscopic level the differences between homogeneous mixtures, heterogeneous mixtures, compounds, and elements

Azeotropes are one kind of mixture that usually poses considerable difficulties regarding the separation processes required to obtain their constituents (physical or chemical processes or, even a blend of them).

Phase diagram of a heteroazeotrope.

Heteroazeotrope

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Phase diagram of a heteroazeotrope.

A heteroazeotrope is an azeotrope where the vapour phase coexists with two liquid phases.

Boiling-point diagram

Vapor–liquid equilibrium

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In thermodynamics and chemical engineering, the vapor–liquid equilibrium (VLE) describes the distribution of a chemical species between the vapor phase and a liquid phase.

In thermodynamics and chemical engineering, the vapor–liquid equilibrium (VLE) describes the distribution of a chemical species between the vapor phase and a liquid phase.

Boiling-point diagram
K Values Diagram (with UNIQUAC Best-Fit Curve), Mixture of Chloroform/Methanol
Vapor-Liquid Equilibrium Diagram

The meeting point is called an azeotrope for that particular pair of substances.

Vapor pressure of a binary solution that obeys Raoult's law. The black line shows the total vapor pressure as a function of the mole fraction of component B, and the two green lines are the partial pressures of the two components.

Raoult's law

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Relation of physical chemistry, with implications in thermodynamics.

Relation of physical chemistry, with implications in thermodynamics.

Vapor pressure of a binary solution that obeys Raoult's law. The black line shows the total vapor pressure as a function of the mole fraction of component B, and the two green lines are the partial pressures of the two components.
Positive and negative deviations from Raoult's law. Maxima and minima in the curves (if present) correspond to azeotropes or constant boiling mixtures.

The system HCl–water has a large enough negative deviation to form a minimum in the vapor pressure curve known as a (negative) azeotrope, corresponding to a mixture that evaporates without change of composition.

Melting temperature as a function of HCl concentration in water

Hydrochloric acid

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Aqueous solution of hydrogen chloride.

Aqueous solution of hydrogen chloride.

Melting temperature as a function of HCl concentration in water
Diagram of alkaline mucous layer in stomach with mucosal defense mechanisms
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Hydrochloric acid as the binary (two-component) mixture of HCl and H2O has a constant-boiling azeotrope at 20.2% HCl and 108.6 °C (227 °F).

Structure of possible acetone polymer

Acetone

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Organic compound with the formula 2CO.

Organic compound with the formula 2CO.

Structure of possible acetone polymer
HPLC readout of an Excedrin tablet. Peaks from left to right are acetaminophen, aspirin, and caffeine.

It does not form an azeotrope with water (see azeotrope tables).