solubility query

[phil-d]

Hi,

 

I am afraid i am a bit of a chemistry dimwit, but i will ask anyway:

I am attempting to dissolve a water soluble compound into an ethanol / propylene glycol solution. The problem is the compound is insoluble in ethanol / glycol, but fully soluble in water. My first attempt was to create a solution in water (successful) then add the ethanol / glycol afterwards....problem is the compound then seems to precipitate out (seems to collect at the bottom of the flask). 

Is there a way to do this? i thought maybe heat the solution to try and break the bonds? Is there an additive i can add (bearing in mind this is for applying to skin).

Sorry if this is a stupid question.

Thanks for you help 

[exchemist]

14 minutes ago, phil-d said:

Hi,

 

I am afraid i am a bit of a chemistry dimwit, but i will ask anyway:

I am attempting to dissolve a water soluble compound into an ethanol / propylene glycol solution. The problem is the compound is insoluble in ethanol / glycol, but fully soluble in water. My first attempt was to create a solution in water (successful) then add the ethanol / glycol afterwards....problem is the compound then seems to precipitate out (seems to collect at the bottom of the flask). 

Is there a way to do this? i thought maybe heat the solution to try and break the bonds? Is there an additive i can add (bearing in mind this is for applying to skin).

Sorry if this is a stupid question.

Thanks for you help 

You can't get round the solubility of a substance in a given solvent in this way. It is what it is. If this substance is water-soluble, it is likely it has some degree of solubility in an ethanol/propylene glycol mixture, as both are also polar solvents. But the solubility may be a great deal lower- as you have evidently discovered.

As for additives, surfactants can sometimes be used to create emulsions, i.e. to suspend rather than dissolve the insoluble material. This is how detergents work to remove grease and oil, for instance, which are not water-soluble.

Maybe if you can explain what you are trying to do in more detail, somebody may be able to advise you further.  

[phil-d]

yes no problem...im basically attempting to replicate an experiment i have read about online where someone has used a 10% sodium bicarbonate solution mixed with DMSO. For my own reasons i am attempting to diverge and used ethanol / glycol as the penetrating vehicle (DMSO suffers the same solvent issues by the way). I am struggling to figure out how they managed to add DMSO without the bicarbonate precipitating out?

[chenbeier]

I think you can only add a solubilizer to make a emulsion.

[phil-d]

thanks - i might try some polysorbate or something and see if that helps