Sciencemadness Discussion Board

Help with solvent extraction and TLC of 5 hydroxymethyl furfural

Triflic Acid - 26-7-2021 at 10:22

Recently made some 5 hydroxymethyl furfural following this paper:
Trouble is, that the workup called for a huge amount of ethyl acetate. I scaled it up 20x as well, since the authors were doing it on a tiny scale. So, I tried to vacuum steam distill off the 5 HMF by adding water to the DMSO extract and heating. Then evaporated the water off under vacuum. Now, I have an syrup I think contains 5 HMF. What eluent should I use to run a tlc on the syrup? And if it doesn't, does anyone have any idea on how to get the 5HMF out of the DMSO without needing a truckload of ethyl acetate?

walruslover69 - 26-7-2021 at 11:16

if you have a good vacuum pump, you could leave it under vacuum for a few hours or overnight, most of the DMSO should evaporate without too much loss of product (hopefully). DMSO has a tendency to never 100% evaporate even on a rotovap and is a huge pain to work with.

The paper used 9:1 hexane:EToAC so that sounds like a good place to start when doing the TLC.

Triflic Acid - 26-7-2021 at 18:24

Yeah, don’t have any hexane sadly. But, dcm seemed to work well. Tlc attached. The dmso screwed things up a bit, but it looks good.

711F0267-B656-4B9C-B4E0-244BA90837A4.jpeg - 3.8MB

Oxy - 26-7-2021 at 20:27

Use much smaller samples and also much smaller concentrations. You should have spots but you have smeared lines which show nothing besides "there is something there".

DMSO is a solvent which I try to avoid as this can be kind of pain in the ass when it comes to extraction. It's not easy to evaporate. Thankfully it is miscible with water and many organics and can be removed by repeated extraction. Also, chromatography column and silica are sometimes handy and with some experience they allow to separate clean product easily. However it's kind of expensive as it requires some solvent (can be purified and reused) and silica gel (or other stationary phase - can't be reused).

Triflic Acid - 26-7-2021 at 21:11

The streaking is not actually because of a large spot, the dmso doesn’t evaporate and carries some of the compound with it. Check Google for more info