I am using N-Methyl-2-pyrrolidone as the solvent for the synthesis of nanoparticles and I need to get rid of the solvent in the final step preferably by washing (i.e. centrifugation, washing with a secondary more benign solvent). Now I cannot evaporate (high boiling point and we do not have specialized rotovap in our lab) and cannot freeze dry my sample.
What is the general recommendation for removing this solvent? Since I am working with the biological safety of my nanoparticles even small amount is not desired.
I appreciate your help in advance.
Thanks
Hi Fatima,
N-Methyl-2-pyrrolidone is soluble in water therefore you can wash your reaction mixture with water and remove water . Good luck
Dear Fatemeh,
Removal of NMP can be challenging, and generally does require the correct apparatus. We would generally not advise using a basic freeze dryer as plastic / elastomer components and the vacuum pump may all suffer damange by NMP. NMP boils at 202°C and melts at -24°C. My guess is that with vacuum alone you will not get the pressure low enough to keep NMP frozen by vacuum alone. You would have to get the pressure to 10 microbar for the BP of NMP to be below the melting point, that is not practially possible in any freeze dryer I know of.
Centrifugal evaporators that can remove NMP are available, however they are expensive and no system, can remove 100% of any solvent. Removing NMP under vacuum requires a good, oil free vacuum pump of the scroll style, a diaphragm pump is not strong enough, a cold trap with sub zero cabability, and a heated system. If you do not heat the pipe work to the trap, the chamber of the system, then NMP will condense in the chamber and pipe work, and damage your evaporation system.
The following application note may help:
https://www.spscientific.com/uploadedFiles/Product_Applications/Genevac/How%20to%20Evaporate%20High%20Boiling%20Point%20Solvents.pdf
If you cannot get access to the necessary equipment for this, then I would seek another solvent that is easier to remove, or, remove NMP via another method replacing it with a solvent that is easier to remove by conventional freeze drying or evaporation.
Kind regards,
Rob
Hi Fatima,
N-Methyl-2-pyrrolidone is soluble in water therefore you can wash your reaction mixture with water and remove water . Good luck
NMP can actually be washed in water. If the sample is kept in water for few days NMP will be removed.
- Badges
- Science topic