Sciencemadness Discussion Board
Not logged in [Login ]
Go To Bottom

Printable Version  
Author: Subject: Breaking azeotropes
Kevlar
Harmless
*




Posts: 16
Registered: 5-2-2024
Location: UK
Member Is Offline


[*] posted on 17-2-2024 at 12:17
Breaking azeotropes


Beyond the general instant information you can research on this subject, when it comes to boiling points 20 - 30 degrees apart. It soon gets difficult to get great seperation!

Some notable examples are
H2O + C2H5OH,
H2O + H2SO4,
CH3NO2 + CH3OH, to name a few.

In the first example H2O + C2H5OH, you can reach 96% ethanol. But distilation no longer will work, so the use of drying agents in needed here, first and best choice is 3A mol sieves. This will get you anhydrous ethanol!

The second example H2O + H2SO4, I personally know no way to break this azeotrope. Or why you would need/want to, no doubt there are applications that need and use anhydrous H2SO4.

The last example CH3NO2 + CH3OH, I could only think of a few methods that could work. Salting out one of the solvents, or using a dean stark apparatus. This and the first example I have used some of these methods, but these 3 examples are but a few of many ways (excluding *2) which I could not find a way to achieve anydrous H2SO4.

I'm sure theres people who are struggling to break azeotropes, and people who have knowledge on methods.

It would be good to compile a list of concise methods for common combinations that have little accessible information on methods and ways to break azeotropes.
View user's profile View All Posts By User
Texium
Administrator
********




Posts: 4533
Registered: 11-1-2014
Location: Salt Lake City
Member Is Offline

Mood: PhD candidate!

[*] posted on 17-2-2024 at 13:41


Quote: Originally posted by Kevlar  
The second example H2O + H2SO4, I personally know no way to break this azeotrope. Or why you would need/want to, no doubt there are applications that need and use anhydrous H2SO4.
The solution to this problem is not to break the azeotrope, but to add SO3 to react with the remaining water, giving anhydrous sulfuric acid, or oleum if excess SO3 is added.



Come check out the Official Sciencemadness Wiki
They're not really active right now, but here's my YouTube channel and my blog.
View user's profile Visit user's homepage View All Posts By User
unionised
International Hazard
*****




Posts: 5109
Registered: 1-11-2003
Location: UK
Member Is Offline

Mood: No Mood

[*] posted on 17-2-2024 at 14:22


In principle, you can break any azeotrope by redistilling at a different pressure.
https://www.chemeurope.com/en/encyclopedia/Ethanol_purificat...

[Edited on 17-2-24 by unionised]
View user's profile View All Posts By User
chornedsnorkack
National Hazard
****




Posts: 535
Registered: 16-2-2012
Member Is Offline

Mood: No Mood

[*] posted on 17-2-2024 at 23:22


Quote: Originally posted by Kevlar  
Beyond the general instant information you can research on this subject, when it comes to boiling points 20 - 30 degrees apart. It soon gets difficult to get great seperation!

Some notable examples are
H2O + C2H5OH,
H2O + H2SO4,
CH3NO2 + CH3OH, to name a few.

In the first example H2O + C2H5OH, you can reach 96% ethanol. But distilation no longer will work, so the use of drying agents in needed here, first and best choice is 3A mol sieves. This will get you anhydrous ethanol!

The second example H2O + H2SO4, I personally know no way to break this azeotrope. Or why you would need/want to, no doubt there are applications that need and use anhydrous H2SO4.

How about freezing?
http://www.sulphuric-acid.com/techmanual/Properties/properti...
Azeotrope is 98,3%. Eutectic is not the same - eutectic is 94%.
A practical issue with concentrated sulphuric acid is that it is viscous and has tendency to supercool.
View user's profile View All Posts By User
solo
International Hazard
*****




Posts: 3967
Registered: 9-12-2002
Location: Estados Unidos de La Republica Mexicana
Member Is Offline

Mood: ....getting old and drowning in a sea of knowledge

[*] posted on 18-2-2024 at 09:04


Reference Information

AZEOTROPIC DATA
L. H. HORSLEY
The Dow Chemical Co., Midland, Mich.

Discription
This table of azeotropes and nonazeotropes si a revision of the wt o pre-
vious tables published in Analytical Chemistry, August 1947 and July 1949
(167, 168), together with approximately 6000 new systems, bringing the total number of systems to over 14,000.
The table is arranged in two parts: (1) table of binary systems and (2) table of ternary systems, followed by a formula index and bibliography. As in the previous tables, the individual systems are arranged according to empirical formula using the Chemical Abstracts system, except that inorganic compounds are listed first ni alphabetical order, followed by or ganic systems in the order carbon, hydrogen, bromine, chlorine, fluorine, iodine, nitrogen, oxygen, sulfur.
For a given binary system the lower ordercompound according to for-
mula is chosen as the A-component and under each A-component the B-
components are likewise arranged according to empirical formula. For
ternary systems the same arrangement is used, using the lowest order for-
mula as A-component, the next lowest order as B-component, and the high- est order formula as C-component.
To facilitate finding al systems containing a given component a for- mula index is included at the end of the tables listing the systems contain- ing a given component.
The following abbreviations are used in the table:
Min. b.p. V-1.
Vol.
M m .
Minimum boiling point azeotrope with no data given Vapor-liquid equilibrium data are given i nthe original reference
Azeotropic concentration is given i nvolume per cent. so indicated, all concentrations are weight per cent
Pressure in mm. of mercury absolute Approximate
Greater than
Lesst h a n
Unless
For systems for which more than one literature reference is available, an attempt has been made to select those data that are most reliable and complete. The auxiliaryreferences for which no data have been given are listed with an asterisk. Where there is appreciable discrepancy in the data of two references, both sets of data have been included.
Because Lecat has published identical data on most of his systems in two or more journals, only his most recent reference is listed here, except where there are large discrepancies ni hisdata, in which case both sets of data have been included.




https://annas-archive.org/slow_download/76e0a17644ca607bdda9...

or,....

Attachment: phpAtLk4q (4.8MB)
This file has been downloaded 84 times

[Edited on 19-2-2024 by solo]




It's better to die on your feet, than live on your knees....Emiliano Zapata.
View user's profile View All Posts By User
chornedsnorkack
National Hazard
****




Posts: 535
Registered: 16-2-2012
Member Is Offline

Mood: No Mood

[*] posted on 18-2-2024 at 11:37


Quote: Originally posted by solo  
Reference Information

AZEOTROPIC DATA
L. H. HORSLEY
The Dow Chemical Co., Midland, Mich.


What file type is it? What softwares open it?
View user's profile View All Posts By User
bnull
Hazard to Others
***




Posts: 224
Registered: 15-1-2024
Location: Between the Atlantic and the Pacific Ocean
Member Is Offline

Mood: Sleepy (again)

[*] posted on 18-2-2024 at 14:10


DjVu. DjVuLibre (https://sourceforge.net/projects/djvu/) opens it.



Quod scripsi, scripsi.

B. N. Ull

P.S.: Did you know that we have a Library?
View user's profile View All Posts By User

  Go To Top