SIlica gel column becomes black while packing with cyclohexane. Why?
I doubt it actually becomes black; it probably just darkens. It has something to do with how light is absorbed and scattered back by the silica/cyclohexane system. A similar thing happens to silica/toluene or silica/benzene. Nothing chemically happens to the silica or solvent; it's a purely physical process.
I doubt it actually becomes black; it probably just darkens. It has something to do with how light is absorbed and scattered back by the silica/cyclohexane system. A similar thing happens to silica/toluene or silica/benzene. Nothing chemically happens to the silica or solvent; it's a purely physical process.
I'm sorry Dr El-Emary, but your answer has nothing to do with the original question.
Dear Paolo Suating
What I've written is just from the paper attached.This paper might taken into consedration while discussion to give wide understanding. Really, as I know n-hexane doesn't interact with silics gel while doing TLC. I'm sorry if I couldn't answer the question as you want.
Dear Sir,
Thanks for responding and suggestions. Refer attached photographs, we have done so many batches in lab and kilolab but never face such problem. This is first time in my 15 years experience silica gel becomes black (one particular commercial batch) while loading in column with cyclohexane. Unable to find the reason.
Dear Deep Chand Agrawal :
Cyclohexane is obtained by hydrogenation of benzene on the catalysts at high temperature. Perhaps your cyclohexane have resins that are silica gel becomes black. Determine the content of resins in cyclohexane.
Best regards.
Dear Sir,
Thanks.
The same Cyclohexane does not giving black color in silica gel (other batch and LR grade). It is something with Silica gel not with Cyclohexane.
What brand od silica are you using? is it different from other ones you used before?
We are using Silica gel mesh size 100-200 (Grade C/C). Its is same as used before.
No exothermicity observed during contact. Neither silica not mislabeled as alumina nor cyclohexane mislabeled as cyclohexene.
Normally, silica gel column doped with silver nitrate (used more often for separation of double bond isomers) turns black because of exposure to light. Any chance you have expensive silver salt contaminating (although hard to believe such expensive will be additive error).
- Badges
- Science topic
- Similar topics
- Chemistry
- Organic Chemistry