I was having the issue that a series of compounds degradate by the mild acidity of chloroform when we perform NMR experiments. I think that these compounds could be terpenoids (dollabellane type). And I wonder if other kind of molecules could degradate or are unestable in chloroform?
I have a problem of stability in chloroform with monoterpenes : pinane with acidic group) or santolinane with ketone. There is not a specific skeleton. For long conservation of samples, chloroform is not good and C6D6 is more adequate.
CDCl3 for NMR has nothing added because it would show in the spectra. But chloroform decomposes under storage, and forms HCl. If a sample is acid sensitive, the spectra will react and side prosucts will form.
There are several ways to avoid this, for instance add some silver foil to the CDCl3 bottle to catch the HCl. I used to add some solid NaHCO3 to my solvent bottle. Then you must use the supernatant liquid, or else filter the solvent just before use. I use a cotton-plugged Pasteur pipette as filter.
Its advisable to keep your samples dry in fume cupboard once you are not running in NMR machine. Keeping them in chloroform for a long time may cause degradation.
- Badges
- Science topic
- Similar topics
- Physical Sciences
- Atomic, Molecular and Optical Physics
- Atoms