[xshadow]

Hi

I synthesized  N/O ethyl saccharin  and then I've dome a gas chromatograpy...but I get 3 peak instead of two.

The third peak which molecule(impurity)  could it be?

The first peak eluited is the N-ethyl saccharin
I don't know which peak is the O-ethyl saccharin
..the one in the middle or the last one?

Ps: I use 10mmol iodoethane with 10 mmol sodium saccharin in DMF.
After the reaction ended I washed with water



Thanks

[Babcock_Hall]

Have you thought about constitutional isomers?  I am not sure how probable this would be.

[xshadow]

Have you thought about constitutional isomers?  I am not sure how probable this would be.

Mhhh
I 'll  think about these...thanks

[Babcock_Hall]

Can you obtain mass spectra on the three peaks?  I see the possibility of two kinds of O-alkylation.

[xshadow]

Can you obtain mass spectra on the three peaks?  I see the possibility of two kinds of O-alkylation.

Can t now
Do you mean also the alkylation through S=O groups?
Thanks

[Babcock_Hall]

I see no reason to exclude this possibility without more data.

[AWK]

Unsubstituted saccharin.

[wildfyr]

I think AWK nailed it. Never forget starting material!

[xshadow]

But does sodium saccharin  have a lot higher boiling point (is a salt)than the two products?

Or is not too much different because is in a solvent (not a solid salt)?

Thanks

[Babcock_Hall]

Now that you have alternative hypotheses, what should you do next, assuming that you had access to all that you needed?

[AWK]

Sodium saccharin is obviously non-volatile at GC. Saccharin is an acid with a strength comparable to that of oxalic acid. If sodium saccharin was present in the reaction mixture, on washing with water, it could have significantly hydrolyzed and a much less water-soluble saccharin was formed, which had only 2 degrees C higher boiling point than its O-ethyl derivative.

[wildfyr]

@AWK I don't like saying the sodium salt hydrolyzed. That implies the N-S bond or N-C cleaving to me. Better to say it acid/base equilibration occurred under aqueous conditions.

[AWK]

Saccharin is a very stable compound.
I do not believe in the possibility of breaking the S-N or C-N bond under the conditions of synthesis and isolation of the alkylation product. The saccharin in the GC sample may only come from an incomplete reaction or from degradation of the O-ethyl derivative upon injection due to traces of water present in the gas chromatographic sample.

[xshadow]

Now that you have alternative hypotheses, what should you do next, assuming that you had access to all that you needed?

NMR/GC MS?

[xshadow]

Sodium saccharin is obviously non-volatile at GC. Saccharin is an acid with a strength comparable to that of oxalic acid. If sodium saccharin was present in the reaction mixture, on washing with water, it could have significantly hydrolyzed and a much less water-soluble saccharin was formed, which had only 2 degrees C higher boiling point than its O-ethyl derivative.

understand!

thanks