Anyone had experience dealing with compounds that just don't want to crystallize?
I have been working with a number of Schiff bases and several of them just won't crystallize. They just form a sticky goo. At first I suspected I was getting some kind of wierd polymer product from over-heating the reaction mixture but I have found that the reaction proceeds without heat and gives the same result.
I guess what I am looking for is a generalised approach to this problem whether its Schiff bases or some other type of compound.
Any suggestions?
The last problem Schiff base I prepared was from Vanillin and 2-Aminothiazole. The reaction proceeded quicky without heat with ethanol as the solvent. The product is red and remains soluble in the solvent. If the solvent is evaporated slowly, a red oily material begins to separate and this eventually solidifies to a sticky mass without crystal formation. I have also tried other polar and non-polar solvents to crystallize it from but with no success. It is quite frustrating.
The fact that vanillin is phenolic may have lead to polymer formation but the product seems too well formed if you know what I mean. It seems to have been a stoichiometric reaction.
- Badges
- Science topic
- Similar topics
- Chemistry