Talk:Azeotrope

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I moved here the Advenced Theory section because it needs rephrasing. (e.g. "We can have", excessive capitalization) A reference would also be useful.--Unconcerned 23:25, 17 Aug 2004 (UTC)

ADVANCED THEORY:

There is another interesting phenomena that has been observed. 
Some azeotropic systems exhibit what is called "Multiplicity"
i.e. Multiple steady states.
For example the ternary system Methanol - Toluene - MethylButyrate
exhibit this Multiplicity.
For the same conditions of input such as Molar feed rate, 
composition, Reflux rate, Distillate flow rate and Column
temperature profiles; we can observe different product compositions,
Temperature profile and internal flow rates.
We can have for example 3 steady states: 2 Stable steady states and
1 unstable steady state.

Contents 1 min/max still not clear 2 Changes to azeotrope definition 3 Examples of Azeotropes 4 Graph -- Is it 2-propanol or 1-propanol?? 5 Complete revision

[edit] min/max still not clear

The negative/positive and minimum-boiling/maximum boiling ideas don't scan, here. Someone who actually groks them needs to say what's varying. I suspect it's the boiling-point temperature varying vs. % concentration of the solute in water. At a certain concentration the boiling point of the mixture reaches a minimum; at any other concentration it will be higher; the concentration with the lowest boiling point is called the "minimum-boiling" or "negative boiling" concentration. I'm 99% sure this is what's meant, but I don't recognize the terminology and I'm too wikilazy to go look it up. Maybe later when the caffeine kicks in... Blair P. Houghton 22:27, 6 Jan 2005 (UTC)

[edit] Changes to azeotrope definition

I changed the definition, so that it was more accurate and also will clear up the last quesiton.

I tried to make a numbered list that would look good, but I don't know much about how to format this.

[edit] Examples of Azeotropes

Are the percentages mentioned by mass, mole or liquid volume ? It should be specified, ethanol-water, 95.5wt% ethanol, (wt=weight)

[edit] Graph -- Is it 2-propanol or 1-propanol??

Every source I looked at indicates that the azeotrope for 1-propanol is at 72% alcohol by weight and that the azeotrope for 2-propanol is at 88% alcohol by weight. The graph given in the article is labeled 2-propanol, but shows the azeotrope to be at approximately 70%. Something is not right here. Karl Hahn (T) (C) 16:09, 8 April 2007 (UTC)

[edit] Complete revision

I have rewritten the entire article, as the template on this talk page requests. I have endeavored to make this difficult subject accessible to a person who has mastered high school physics. The article is much longer now, but it progresses in bite-sized steps, starting with the basics, and moving to more and more difficult concepts. I have eliminated the graph that was in the original article because the way it illustrates the azeotrope concept is too abstract for most readers. The graphics that I find are the most accessible are those that plot composition against temperature at constant pressure. There is also one graph that uses the more difficult illustration of composition against pressure at constant temperature, but it is necessary to understand the relationship between azeotropes and Raoult's law. I hope I have produced something of worth here. Please post any feedback you have on my efforts here. Karl Hahn (T) (C) 21:36, 14 April 2007 (UTC)

I think there's something wrong with the TXY phase diagrams. Should the composition axis have both x₁ and y₁ go from 0 to 100% from left to right? If I'm reading it right, the diagram have a pure component solution of 1 boiling to a pure component vapor of 2? Never mind. I misinterpreted "X" and "Y".