synthesis of schiff bases

[umofiae]

I have been able to synthesize some compounds (which i believe are Schiff bases) using vanillin and the isomers of toluidine via three different methods,with a change in solvent and reaction conditions. while two methods gave crystals, the other gave an oily product. i am wondering why this happened. Could it be because of the change in solvent and reaction conditions? Also, what other method can i use in purifying the oil apart from column chromatography? thanks

 

-umofiae

[Elite Engineer]

Probably not due to changes in reaction conditions, but due to one of the isomers you used that yielded a product with a lower melting point than the other two crystalline products. What were the products you

 

made?

 

How pure of a product do you want if you don't intend to use column chromatography? As an alternative you can use a non-polar solvent and then a polar solvent to extract impurities out or distillation.

 

~EE

[umofiae]

ok..thanks for your reply...the products where o-tol-van, m-tol-van and p-tol-van. the solvents used were water, ethanol and ethanol/water (1:1). the m-tol-van for the 3 methods and solvents gave oils while the o-tol-van and p-tol-van products gave crystals for water and ethanol/water, however it gave oils when synthesized with ethanol...That's my conflict... With regards to the purification of the products, running a column seems to be the best idea. With regards the alternative you gave, will that be done using a separatory funnel?

[hypervalent_iodine]

You should really be doing something along the lines of a liquid-liquid extraction with a sep funnel to semi purify your products as a matter of course for these things (but be careful not to ruin your products in the process). Have you run a TLC with any of your products? Also, a lack of crystals can often just mean that you haven't dried the product properly, so try removing all of the solvent using high vacuum if you haven't already and see if that helps.

[Elite Engineer]

With regards to the purification of the products, running a column seems to be the best idea. With regards the alternative you gave, will that be done using a separatory funnel?

You can. TBH I'd follow what hypervalent_iodine says, he/she is more rounded on this stuff. However, you can you a sepratory funnel, but personally, I'd use hexane, or ether filter it, and then just

 

evaporate the hexane/ ether to obtain the product.

 

~ee