After discovering a solvent system (EtOH:CH2Cl2 1:15) with TLC silica plates, I run my reaction mixture with C.C. in order to purify my product. I packed a relatively high and wide column with silica gel. I managed to collect fractions containing pure product (image2). These same fractions after two days in RT have completely different apperance on TLC (image 3). Any idea of what is happening? Is it possible my compound is unstable?
Notes:
1. I view my TLC under UV 366nm.
you have only two image in your file the first one included four spots of your sample and the second have eight spots . its hard to guess what is happened unless know what is your reaction?.
You have right. I made a mistake with numbering of images. The first image include some representative fractions imediately after purification with C.C. and the second image include some representative fractions after two days .
Dear Eleni,
I don't know the structure of your compound but probably it could be enstable.
Hovewer, the solvent sistem is very polar and usually I don't suggest the use of methanol (or ethanol) more of 20% becouse is possible that this solvents solubilize the silica gel and then silica is present in the pure product...have you tried other solvents such as Ethyl acetate:Methanool 8/2 or Ethyl acetate:Triethyl amine 8/2 or extrimely Ethyl acetate:Triethyl amine:Methanol 7/2/1 ???
Finally, why you wait 2 days to remove the solvent? it is possible that by-products are formed after some time, have in the molecule groups that can react with ethanol?
you can dry your products in the vacum to Speeding up your drying proccess.
and i I recommend to use solvens:ethyl asetate/n-hexan with different Ratios
Depending on your products polaritylike;9/1, 8/2 or...
you can also use pure n-hexan if your product is too nonpolar
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