Hey scientists,
I am just wondering what functional groups can be added to a hydrophobic molecule to make it water soluble at basic pH?
As a case study, let's just consider ethyl benzene as the scaffold. Not very soluble in water.
How can we make it soluble at basic pH? But extending functional groups to the carbon chain.
I know for instance, that you can have ethyl benzene. It can be made soluble at acidic pH by adding an ammonium chloride group. If you could convert ethyl benzene to phenethylamine by adding an amino group to the carbon chain then you got ethyl benzene. Still not very soluble. But if you react phenethylamine with HCl then you group phenethylamine-HCl or phenethylammonium chloride which is very water soluble at pH less than or equal to 7.
If you had ethyl benzene, what functional group could you add to make it soluble at basic pH?
I think that if ethyl benzene if we added a COOH group to the carbon chain we would have 3-Phenylpropanoic acid . If we reacted NaOH with that we would have 3-Phenylpropanoate Sodium Salt which I predict would be soluble at basic pH.
Is that correct? What other functional groups could I add to ethyl benzene's carbon chain to make the molecule water soluble at basic pH. Are there any functional groups that I could add to the carbon chain of ethylamine to make the molecule water soluble at basic pH and also positively charged? Like for example phenethylamine-HCl is positively charged but only soluble at acidic pH.
Anything that would have a charge at basic pH, such as phosphate, sulfate, carboxylate, or tetrazole would help with solubility, but these are negative charges, of course. A quaternary ammonium group has a positive charge.
Anything that would have a charge at basic pH, such as phosphate, sulfate, carboxylate, or tetrazole would help with solubility, but these are negative charges, of course. A quaternary ammonium group has a positive charge.
Not a direct answer to the question but DMSO dissolves aprotic organic compounds and is readily miscible in ionic solvents so is it necessary to change the molecule or can you just dissolve it in dmso before proceeding to the next stage in aqueous solution?
Add a PEG group. It is neutral, so does not depend on pH. But if you do not mind negatively charged species, add an OH to aromatic ring creating a phenolic functional group that will be at least partially ionized at basic pH.
See Patent 6,127,349. The patent describes making phosphocholine derivaties to increase solubility. The derivatives are amphoteric and charged over a wide pH range.
Compounds or functional groups that would ionize or have charge at basic pH, may help to make the resulting compound to be hydrophilic like Sulfhydryl, amine etc
Reacting fatty acids with sodium hydroxide, will give water soluble product
- Badges
- Science topic
- Similar topics
- Chemistry