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Topic: Azeotrope


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In the News (Fri 24 May 19)

  
  Azeotrope mixtures with perfluorobutylethylene - Patent 6793840
An azeotropic composition of from 51 to 50 mole percent of perfluorobutylethylene and from 49 to 50 mole percent of bromochloromethane, the composition having a boiling point of from 60.degree.
Azeotropic compositions are also characterized by a minimum or a maximum in the vapor pressure of the mixture relative to the vapor pressure of the neat components at a constant temperature.
The azeotropic compositions comprise 30.7 mole % PFBE and 69.3 mole % trans-DCE at 35.3.degree.
www.freepatentsonline.com /6793840.html   (0 words)

  
 Re: Is it possible to lower the boiling point of water by adding a substance?
The phenomenon to which you refer is that of forming an azeotrope, a mixture of two liquids which cannot be separated by distillation because the mixture has a lower boiling point than either of the pure liquids.
Azeotroping is why you cannot isolate ethanol by distillation without using a drying agent, something that preferentially soaks up water.
It sounds like what you are after is an azeotrope of some substance with water, in which water is the major component.
www.madsci.org /posts/archives/sep99/936336896.Ch.r.html   (0 words)

  
  Azeotrope Summary
Azeotropes or azeotropic mixtures occur for a number of important chemical compounds but perhaps the most important is the ethanol-water mixture.
An azeotrope is a mixture of two or more compounds (molecules) which at a specific composition (ratio of compounds) maintains vapor and liquid phases which are in equilibrium and identical in composition.
Use azeotropic distillation, by adding in a third component which will generate a lower boiling heterogenous azeotrope that can be broken by phase separating the two immiscible liquids and decanting.
www.bookrags.com /Azeotrope   (1206 words)

  
  U.S. Patent: 5514251 - Process for the removal of water from a solution by azeotropic distillation and process for the ...
It is known that, in an azeotrope, the concentration of the constituents, the temperature and the vapour pressure are interdependent parameters.
In the process according to the invention, the entrainer generally chosen is a fluorohydrocarbon which forms with water an azeotrope, the boiling point of which is lower than the boiling point of the compound other than water present in the solution, such that the water/entrainer azeotrope is removed in the vapour state during the distillation.
It is also possible to split the water/entrainer azeotrope into its constituents, for example by drying using desiccant substances, or alternatively by phase separation when the azeotrope is a heteroazeotrope, as is the case for the compositions 1,1-dichloro-1-fluoroethane/water and 1-chloro-1,1-difluoroethane/water.
www.everypatent.com /comp/pat5514251.html   (4416 words)

  
 Azeotrope - Homedistiller   (Site not responding. Last check: 2007-10-29)
An azeotrope is a liquid mixture of two or more components which has a unique constant boiling point.
This azeotrope may boil at a higher, lower, or intermediate temperature, relative to the constituent liquids, and the liquid retains the same composition as it is boiled.
An azeotrope is said to be positive if the constant boiling point is at a temperature maximum, and negative when the boiling point is at a temperature minimum.
homedistiller.org /mediawiki-1.6.8/index.php?title=Azeotrope&printable=yes   (172 words)

  
 Computation of Homogeneous Azeotropes   (Site not responding. Last check: 2007-10-29)
Our work this past year on the homogeneous azeotrope problem grew out of discussions with industrial colleagues who noted that, on systems that have no azeotropes, it was often difficult to tell whether the equation solving routine failed because there were in fact no azeotropes to be found, or failed because of some numerical difficulty.
Furthermore, conventional methods for computing azeotropes are generally based on the assumption that there is only one azeotrope for a given set of components.
The determination of the existence and composition of homogeneous azeotropes is important both from theoretical and practical standpoints.
www.nd.edu /~markst/globsol/wn34/node4.html   (749 words)

  
 In Depth Look at Extractive Distillation
In the context of the T-x, y phase diagram, these points are called the minimum boiling azeotrope (where the boiling temperature of the azeotrope is less than that of the pure component) or maximum boiling azeotrope (the boiling temperature of the azeotrope is higher than that of the pure components).
the homogeneous azeotrope, where a single liquid phase is in the equilibrium with a vapor phase; and the heterogeneous azeotropes, where the overall liquid composition which form two liquid phases, is identical to the vapor composition.
Thus, in addition to azeotropic mixtures which require the addition of a miscible separating agent in order to be separated, homogeneous azeotropic distillation also includes self-entrained mixtures that can be separated without the addition of a separating agent.
www.cheresources.com /extrdist.shtml   (3556 words)

  
 Azeotropic Distillation Reverse Osmosis water treatment membrane filtration filters distillers Filter   (Site not responding. Last check: 2007-10-29)
Azeotropic distillation treatment is any of a range of treatment used to break an azeotrope in distillation.A common distillation with an azeotrope is the distillation of ethanol and water.
It also depends on the knowledge that an azeotrope is not a range of concentrations that can not be distilled, but the point at which activity coefficients are crossing one another.
Azeotropic distillation treatments are of course extremely more complex, hence calculations are not straightforward as for simple distillation columns.
www.discountreverseosmosis.com /Azeotropic-Distillation.htm   (457 words)

  
 VLE_home
The fl lines show the ideal pressures for the system and the difference between the colored lines and the fl lines are due to the nonidealities of the liquid mixtures as expressed by the activity coefficients.
The azeotrope point is the point where x = y and the y-x plot crosses the 45-degree (fl) line.
This particular system does not have an azeotrope, but if the negative deviations were large enough in comparison to the relative volatilities of the two pure components, then a minimum pressure would occur.
www.et.byu.edu:8080 /~rowley/VLEfinal/background2.htm   (1778 words)

  
 Solvent Recycling and Azeotropes
Acetonitrile boils at 81.6 ºC and water boils at 100 ºC. The mixture forms an azeotrope which boils at 76.1 ºC and which is composed of 86% acetonitrile and 14% water.
A common ternary azeotrope found in solvent recycling is Acetonitrile, water and methanol.
Acetonitrile boils at 81.6 ºC, water boils at 100 ºC and methanol boils at 64.5 ºC. When mixed together the three form an azeotrope that boils at 65-70 ºC and is composed of 44% acetonitrile, 52% methanol and 4% water.
www.solvent--recycling.com /azeotrope_1.html   (377 words)

  
 Distillation Theory and its Application to Optimal Design of Separation Units - Cambridge University Press   (Site not responding. Last check: 2007-10-29)
= 1), d is an azeotropic mixture with minimum temperature, e is a mixture with a so-called inner tangential azeotrope, f is a mixture with two azeotropes, g is a heteroazeotropic mixture, and h is an azeotropic mixture with two liquid phases.
Azeotrope is a binary or multicomponent mixture composition for which the values of phase equilibrium coefficients for all components are equal to one:
Later, the residue curves of three-component azeotropic mixtures were studied in the works of Reinders & De Minjer (1940a, 1940b) for the azeotropic mixture acetone–chloroform–benzene and more widely in the works by Bushmakin & Kish (1957a, 1957b).
www.cambridge.org /catalogue/catalogue.asp?isbn=0521820928&ss=exc   (2591 words)

  
 EtOH distillation
An azeotrope is a liquid in equilibrium with vapor of exactly the same composition; this means that distillation of an azeotrope and condensation of the vapor gives the same liquid with which you started.
The lines intersect at the azeotrope and are so close together from there on up that the gap can hardly be seen.
The composition of the azeotrope changes with pressure, and distillation at a different pressure is one way to get above the azeotrope.
www.rpi.edu /dept/chem-eng/Biotech-Environ/DOWNSTREAM/azeotrop.htm   (0 words)

  
 Obscura: Azeotrope
An azeotrope is a mixture of two or more compounds (molecules) which at a specific composition has a vapor in equilibrium with that liquid with the same composition as the liquid.
This means that you cannot change the composition of that liquid at its azeotropic composition by simple boiling.
The exception for binary mixtures is the rare double azeotrope.
www.mdcbowen.org /obscura/2006/06/azeotrope.html   (0 words)

  
 A - Glossary of chemical terms
Azeotrope is a mixture of two liquids that boils at constant composition, i.e.
Azeotropes occur because of deviations in Raoult's law leading to a maximum or minimum in the boiling point - composition diagram.
The composition of an azeotrope depends on the pressure.
www.ktf-split.hr /periodni/en/abc/a.html   (2092 words)

  
 Ethanol: ethanol production, ethanol plant, cellulosic ethanol   (Site not responding. Last check: 2007-10-29)
Fractional distillation can concentrate ethanol to 95.6% volume; the mixture of 95.6% ethanol and 4.4% water (percentage by weight) is an azeotrope with a boiling point of 78.2 °C, and cannot be further purified by distillation.
Benzene, ethanol, and water form a ternary azeotrope with a boiling point of 64.9 °C. Since this azeotrope is more volatile than the ethanol-water azeotrope, it can be fractionally distilled out of the ethanol-water mixture, extracting essentially all of the water in the process.
At pressures less than atmospheric pressure, the composition of the ethanol-water azeotrope shifts to more ethanol-rich mixtures, and at pressures less than 70 torr (9.333 kPa), there is no azeotrope, and it is possible to distill absolute ethanol from an ethanol-water mixture.
winelib.com /wiki/Ethanol   (3842 words)

  
 Update in Anaesthesia Issue 18
The azeotrope appears to break down in the body, and halothane, having lower blood solubility than ether, is excreted more rapidly during the early phase of recovery.
Although the azeotrope is nonflammable in air, the ether component is flammable, so the azeotrope should be prepared in a well-ventilated area, away from sources of ignition.
The azeotrope of halothane and ether appears to share many of the virtues of its constituent parts, while ameliorating their undesirable properties.
www.nda.ox.ac.uk /wfsa/html/u18/u1811_01.htm   (1527 words)

  
 Micro-Scale distillation
An azeotrope is a constant-boiling mixture with a sharp boiling point, and a well-defined composition (similar like a eutectic mixture).
Since the boiling point of ethanol and the azeotrope of ethanol:water are too close, the water cannot be removed using the minimum boiling azeotrop.
First a ternary azeotrope would distill to remove the water, then the binary azeotrope to remove the benzene, leaving behind the pure ethanol in the distillation pot.
www.chem.ucla.edu /~bacher/Specialtopics/Distillation.html   (1376 words)

  
 Distillation
When an azeotropic mixture is heated, the vapor has the same composition as the liquid and consequently, the distillate has the same composition as the original liquid and no separation is achieved by distillation.
For instance, mixtures of A and B with compositions different from the azeotrope can only be partially separated into their components by fractional distillation.
Any mixture richer in B than the azeotrope will give azeotrope and pure B. eotropic mixtures can be separated by distillation by changing the applied pressure because the shape of the phase diagram, including the composition and boiling point of the azeotrope, depends strongly on the applied pressure.
www.uwlax.edu /faculty/koster/Distillation305.htm   (3070 words)

  
 Ethanol
the material that has the lowest boiling point) is the first material to distill from the distillation flask, and this material is the azeotrope of 95% ethanol which has the lowest boiling point.
Most azeotropes, like 95% alcohol, have boiling points lower than those of their components, and are known as minimum-boiling mixtures.
Azeotropes having boiling points higher than those of their components are known as maximum-boiling mixtures.
www.ucc.ie /academic/chem/dolchem/html/comp/ethanol.html   (905 words)

  
 Chemical plant design & operations - Reversing Bottoms/Distillate in simple distillation?
Nitric acid/water is an azeotropic system that has the azeotrope at ~70% HNO3 and boils at 122C, 1 atm.
Happily furfural-water make an heterogeneous azeotrope meaning that on condensation they separate in two phases (one rich in furfural, the other in water) a fact that helps to get their full separation in two towers.
I know that it is difficult to grasp, but the general point is that when two liquids form an azeotrope (high boiling or low boiling) the azeotrope becomes one key component in distillation.
www.eng-tips.com /viewthread.cfm?qid=47490&page=82   (906 words)

  
 Azeotrope Databank
To view an azeotrope's properties, please enter the name of a component in the component 1 box.
A list of components which for azeotropes with the entered component will be displayed in the component 2 box.
Selecting one of these will display the azeotrope properties of these two components.
www.ecosse.org /chemeng/azeotrope_bank.html   (0 words)

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