Sciencemadness Discussion Board

Solubility of organic amine salts

ampakine - 19-7-2011 at 05:43

Can the solubilities of the various salts of an organic amine be predicted or is it something that can only be determined experimentally? For example aniline. I know the STP solubility of aniline in water and a wide range of solvents but what if I needed to know the solubility of aniline sulfate or aniline hydrochloride would I be able to predict these solubilities based on the solubility of the free base?

woelen - 19-7-2011 at 06:43

In general this cannot be predicted. It might be that the free amine is much less soluble than the salt, especially if the free amine has a big organic part which is mostly hydrocarbon wthout hydroxyls or carbonic acid parts in it.

Usually the amine HCl or amine H2SO4 salts are soluble in water quite well. The smaller amines indeed are very soluble and most of them also are hygroscopic.

ampakine - 19-7-2011 at 07:28

I bet in the future we'll develop complex algorithms that we'll feed to computers to predict this kinda thing. Just a matter of time before we uncover natures algorithms :D Until then though it bothers me having to refer to charts to find out solubilities.

tmb - 19-7-2011 at 07:35

The arrogance of man:
Nature = human mathematical theory.
Many physicists would agree, at least :)

ampakine - 21-7-2011 at 02:17

Quote: Originally posted by tmb  
The arrogance of man:
Nature = human mathematical theory.
Many physicists would agree, at least :)


No I don't mean nature can be summed up by a mathematical algorithm, I mean that nature uses mathematical algorithms. Good thing for us too because the periodic table would be of much use to use if the elements didn't follow any kind of trends. I think that the true nature of the universe/reality is far beyond anything humans will ever be capable of understanding even a small percentage of (because by our very nature we are incapable of comprehending various mechanisms of reality and if we were to be capable of it we would no longer be human) so you're preaching to the choir when you point out the arrogance of many so called scientists these days. Mathematics is a science of the universe though, man just happened to learn a bit about it over the years so I don't think theres anything anthropocentric about assuming that many of the laws and properties of the physical world are governed by mathematical rules.

[Edited on 21-7-2011 by ampakine]

tmb - 21-7-2011 at 05:23

I only meant it as a passive-aggressive comment :) ; but since your response is interesting:
I would disagree that nature "uses algorithms". Mathematics is something that man has imposed upon nature in order to understand it 'in his own-terms'; rather than being a fundamental property that has been "discovered".

With time, and generations of repetition, it has come to be embraced as 'reality'; and the fundamental-laws to which nature conforms - Laws being a very human concept.

Just a few hundred years ago people dedicated their lives to creating an Earth-centered model of the solar-system. Which almost worked (but for a little-more manipulation), and from which useful, and remarkably-accurate predictions could be made. And now physicists are on the verge of a 'theory of everything'; but for a little-more mathematical complexity.

This is not to say that mathematics is useless, or wrong; but is nature, at its core, represented by human logic? Perhaps this belief stems from the Judeo-Christian influence; that "Man was created in God's image", and so man may become-again as gods, and 'understand'. Or could it be that for all the time and effort - and 'belief' in the fundamental-truth of the mathematical model - this is the very-thing holding us back? Just a thought. :)

wightolore - 22-7-2011 at 09:42

Reading this discussion alone makes me happy that I've found this place.

I too hate referring to sources for solubility information. Sometimes without the compound separated in the first place its damn near impossible to know if you're doing it right.

That and the nature vs man discussion between tmb and ampakine is most interesting.

:) <3

poisoninthestain - 22-7-2011 at 15:11

when it comes to salts oxalate and calcium salts of most amines especially larger molecular weight amines are usually poorly soluble in water while hydrochlorides and sulfates quite soluble.

Random - 23-7-2011 at 03:05

Aniline zinc chloride double salt should be insoluble as it's written in purification of laboratory chemicals book.

ampakine - 23-7-2011 at 04:20

Quote: Originally posted by tmb  
I only meant it as a passive-aggressive comment :) ; but since your response is interesting:
I would disagree that nature "uses algorithms". Mathematics is something that man has imposed upon nature in order to understand it 'in his own-terms'; rather than being a fundamental property that has been "discovered".

I don't know about that. To me quantity seems to be a fundamental property of the universe which is why I assume that mathematics being the science of quantity is a science of the universe. I see your point though, it may just be that my human logic renders me incapable of comprehending how mathematics is just another man made theory we've imposed on nature in an attempt to unravel its mechanisms. I was reading an article on cancer cures yesterday:
http://heartspring.net/cancer_natural_cures.html
and came across something that instantly peaked my interest. In that article they claim that the medicinal properties of Cats Claw was discovered by the Ashaninka tribes indigenous to areas of the Peruvian Amazon and supposedly the Ashaninka claim to be able to "see" whether the plants have the medicinal properties or not because they can see the spirits of the plants. They also claim that plants without the healing spirit when mixed with plants with the healing spirit will cancel out the healing spirits properties. This would be considered pure superstition by westerners if they weren't spot on 100% of the time in their predictions as to whether or not the plants have the medicinal properties. Western scientists have recently discovered that the Cats Claw plants that have medicinal properties contain pentacyclic oxindole alkaloids (POAs) but no tetracyclic oxindole alkaloids (TOAs) and that when TOAs (alkaloids with no healing propeties) are mixed with POAs they cancel out the TOAs medicinal properties. What really peaked my interest here is the fact that the Ashaninka are the people the anthropologist who wrote DNA The Cosmic Serpent claims to have spent time with. In his book he says that these people claim that their extensive knowledge of medicinal plants comes directly from the visions induced by Ayahuasca. His theory is that the logic of people of the western world is incapable of comprehending the mechanisms of which Ayahuasqueros become aware and derive knowledge from. I can't really describe it myself, anyone who hasn't read it I highly recommend reading DNA The Cosmic Serpent.

Quote: Originally posted by tmb  

This is not to say that mathematics is useless, or wrong; but is nature, at its core, represented by human logic? Perhaps this belief stems from the Judeo-Christian influence; that "Man was created in God's image", and so man may become-again as gods, and 'understand'. Or could it be that for all the time and effort - and 'belief' in the fundamental-truth of the mathematical model - this is the very-thing holding us back? Just a thought. :)

I can't really put it into words but I see what your saying. The author of DNA The Cosmic serpent describes it as "objectifying ones objectifying gaze" or something along those lines. I read the book years ago and recently started rereading it. It influenced me a great deal and probably played a large role in my decision to start studying chemistry and become a scientist (in the future). The book is far more interesting now that I'm rereading it because I now know a fair bit of contemporary biochemistry theory. People with a background in chemisty have a different vantage point that may allow them to see many things that the author of that book (who was an anthropologist) could not.

[Edited on 23-7-2011 by ampakine]

tmb - 23-7-2011 at 10:09

Mathematics is seductive: By its inherent logic, it proves itself to be 'true', time after time;
Philosophy is seductive: By its inherent logic, it proves 'truth' to be an illusion, time after time;
DMT is seductive: It... Oh... Wow! (time after time).

As a skilled ayahuascero, I've sung us safely-back from where we came; to an organic amine.
Like a mathematical problem, or a philosophical debate, we could only-ever arrive at our origin.

I'll give that book a read. Nice talking to you.

(Oh, and may I recommend the works of Jan Kounen: "Other Worlds" and "Blueberry" (aka "Renegade") - if you haven't seen them).

[Edited on 24-7-2011 by tmb]

fractional - 24-7-2011 at 00:04

Quote: Originally posted by Random  
Aniline zinc chloride double salt should be insoluble as it's written in purification of laboratory chemicals book.


The aniline zinc chloride double salt is actually quite soluble in water. This property can be used to purify raw quinoline prepared by e.g. the Skraup-reaction. The quinoline zinc chloride salt crystallizes out whilst the unreacted aniline stays in solution in the form of the aniline zinc chloride double salt. Incidently I have done this reaction only yesterday... (for the procedure see e.g. Vogel, Textbook of Practical Org. Chem., 3rd ed. ,1957, p. 829)