You can apply pressure up to 22 psi

 Hi Omar, Thanks for the answer. Is it also for Dowex 1x8? I cannot find this number on Dow website; however, they do recommend 22 psi for another cation exchange resin. Can you please tell me from where you got this datum of 22 psi ?

Hi,

I cannot give any specific numbers or references but for many years I was using Dowex1x8 in pressurized columns.  Roughly speaking the pressure must have been around 40-50 psi in my most common arrangement. It might be higher than the recommendations (though I have never checked them) but separation of traces actinides as well as transition metals was working very well.

I suspect that the size of the resin beads is the factor which counts. Given pressure might result in different flow speed depending on the beads size, thus affecting separation process. 

hope that helps

Hi Krzysztof, thanks, a lot. That's helpful. So basically the beads (200 mesh) won't be destroyed on application of pressure, which was my worry.

I'd be very surprised if that happened. This type of resin is also used in vacuum systems and I have never heard of any troubles caused by the pressure (but as I mentioned, faster flow may result in worse separation parameters - but that's another issue).

Okay, I actually observed slower flow rates on applying pressure. I think the soft beads forms a stiff block kind of thing on application of pressure which leads to decreased flow. 

Might be the case but still it's a bit strange to me. A few times I experienced sort of 'stucking' of the column - but it was caused by some precipitate present in the solution rather than by the resin itself. Solutions with dissolved salts close to the saturation point tend to crystallize on the column (often happens in 9 M HCl).

It's good to store the resin in water (or some kind of conditioning solution) for a few hours prior to the column loading - it allows the beads to soak the water in and “swell” a bit, so the exchange process in the column is facilitated. I could imagine that when loading fresh resin (straight from the bottle) onto the column and rinsing it with conditioning solution,  there can be sort of swelling of the resin (beads expand a bit when absorbing water) and that might affect the flow speed, but that’s actually my guessing.

What size of the column do you use and what kind of solutions?

Thanks for detailed explanation. My column is not very big. It is just 100 cm long and 3 cm wide. I use water to wash the beads and then use pure DMF

Ok, my columns were usually 6-8 mm in diameter and 10 cm long... ;) And I was mostly using water solutions - maybe that's why we have different observations.

best regards

yes, you are right. Large columns behave very differently than small columns. 

But still I'm quite confident regarding the pressure, as long as the resin itself is chemically resistant to the solvent.

How to convert dowex 50wx8 resin ( hydrogen form) into tetrabutylammonium form?

Tanmay Pati: Try and pass aq. solution of tetrabutylammonium chloride through it under gravity 2-3 times and measure the pH of the eluent using a pH paper . I would refrain from using TBAF as HF might degrade the Dowex beads. I never performed cation exchange of Dowex beads but this is what I can think of. 

Hello all,

I just started using this resin for natural product fractionation. I packed the column using 100% MeOH. At first, the solvent eluted as light yellow. Do you think the resin is dissolved in MeOH or this color comes from the impurities from the production lane? Anjul Khadria stated he is using 100% DMF with his column. Do you think organic solvents are harmful for ion exchange resins, especially for Dowex® 1X8 chloride form?

Best,

Serkan