[coolsuman]

i am doing M.tech project. how this separation has to economically?
i had done already by conventional distillation. i acheived 98.5% putiry. is there any other method to separate methanol of same purity. is there any solvent which doesn't dissolve in water.

[technologist]

U can search for the use of high carbon chain phosphene oxides e.g. octyl phosphene oxide etc. I am not sure if it will be usable for methanol or not.

[C6H8O7]

This may sound like a newb answer but have you considered any sort of this into the equation

http://en.wikipedia.org/wiki/Freeze_distillation

I would imagine that there is probably not any sort of workaround for an initial distillation because the 19/1 ratio means that a few different purification methods are unavailable.Freeze distillation in particular seems like it would work for this but with that much water pretty much all of your methanol would be encased in the ice.If you had a smaller ratio like say 1/4 dry ice should get things cool enough to separate everything although the loss of product may be much greater than with simple distillation.

[eugenedakin]

Hello C6H8O7,

You have provided a valiant effort to fix this persons problem. Unfortunately, it doesn't look like its going to work. When you mix methanol and water, they act like one chemical.

I liked your reference. Here is the portion from your reference that provides an answer

Such enrichment by freezing of a solution in water is sometimes oversimplified by saying that, for instance, because of the difference in freezing points of water (0 °C/32 °F), and ethyl alcohol (-114 °C/-173 °F), “the water freezes into ice...while the ethyl alcohol remains liquid.” This is false, and although some of the implications of that description are true and useful, other conclusions drawn from it would be false.

Unfortunately, the ice will not freeze before the methanol does.

I like your logic and the ability to think 'outside of the box'.

Please keep up with the great ideas!

Eugene

[C6H8O7]

Ok then I will make a learning experience out of this.What if the solvent was slightly soluble instead of fully.I know some things can change the solubility of things on a temporary scale.

I have been reading a bit about sulfolane which has the ability to be soluble in water and hydrocarbons.Untill recently I wasn't aware of something that can penetrate both.It seems unlikely that in the wide world of and daunting numbers of man made chemicals we have not found something that can bond to the methanol and change its solubility.Or a process similar to the H20

I haven't really gotten a chance to mess around with anything more than basic solvent theories yet.I feel like I learn a lot from this forum.

[eugenedakin]

Hello C6H8O7,

The good news is that you are thinking in a good direction. There definately are reactions with methanol that can 'use up' the methanol, and I have heard of 'salting out' methanol (I actually haven't performed it myself, so I don't know how successful it is).

The negative aspect of this reaction is that it uses more energy to convert the methanol, and convert it back, than what it takes to perform a simple distillation of the methanol-water mixture.

The last aspect is the case of side reactions. Chemistry can sometimes be unpredictable (that is what makes it so interesting  ).

Well done.

Sincerely,

Eugene

[technologist]

Hello C6H8O7,
What is referred by you is also known as Melt Crystallisation as it was started for the purification of solids. (This is also mentioned in the referred article).

The system was extended for the separation of Glycol & Water. you can refer my earlier post as Eugene also participated in that.
In fact I did lab experiment for that but could not complete it due to other assignments. The important thing is the Freezing point curve for the mixture at different concentrations.

You have to study those curves first then evaluate the system for energy required.

Eugene I also read salting out but with alcohols you can salt out moisture using Sodium sulfate or carbonate but not methanol. Whereas for mineral acids if we use TOPO (as mentioned above in my previous post) than you can recover those acids in the forms of weak ammonium salt or similar things.

[eugenedakin]

Hello technologist,

Thank you for your thoughts and comments.

Sincerely,

Eugene

[verotxu]

Hello!

Have you thought about hydrophobic PV? It might be succesful

CHeers