To get a clean 1H NMR spectrum without any unwanted grease peak in aliphatic region avoid the use of grease while using quick fit a glass wares ,Dry the sample under vacuum to remove the solvent peaks.

Madhukar Baburao Deshmukh sir, we are avoiding grease by using column without any joints, but some unwanted aliphatic junk peaks are appearing arpound 1-1.5 in all of our datas. It may not be grease but maybe water or something else we dont know. Even continuos drying under high vacuum is not working.

Deepak Ranjan Mishra Firstly, I recommend these two papers about residuals peaks in NMR:

Organometallics 2010, 29, 2176–2179 (https://www3.nd.edu/~hgao/JOC1997p7512.pdf)

and J. Org. Chem. 1997, 62, 7512-7515 (http://ccc.chem.pitt.edu/wipf/Web/NMR_Impurities.pdf)

If you know them already, and don't have answer, I think that maybe you have the same problem as me before. When I use hexane:ethyl acetate eluent I have some residual peaks in the aliphatic region. It turned out that our hexane (from glass bottles, for hexane from plactic containers its normal to have impurities) have some impurities, which possess high boiling point (about 0.1-0.5% by weight) . After that, we distill all hexane and our problems are over.

Dear Deepak, thank you for sharing this interesting technical question with the RG community. You have already received a few potentially helpful answers. However, it is a bit difficult to give you a qualified answer because some essential information is missing in your question. Clearly the additional peaks in your 1H NMR spectrum point to some saturated hydrocarbons (solvent residues). Thus it would be interesting to know which solvents you used in your preparation. Moreover, it would be very helpful if you could provide some additional information about the nature of your compound, particularly if it is a liquid (oil) or a solid. In the first case you can try purification by vacuum distillation, while in the second case you can try recrystallization form a suitable solvent.

I hope this helps. Good luck with your work!

Hi Deepak,

I agree with Tiwari. If you Know the solvents peaks you can answer them it is solvent peak that is not a problem. Reviewers would be consider your request. I also faced same problem.

If your product is solid you can dry it or wash it with non-polar solvents. It could be avoid aliphatic peaks in NMR.

Thanks

Anusha