I ball milled a mixture of ethanol,ethylene glyco and yttrium ytterbium oxide. I used rotary evaporator to dry this mixture but it is not drying.Please who can help me out? Ethylene glyco was used as dispersant.
I used a vacuum at 130mbar, bathing of temp 55 degrees rotation at 25 rpm.
Hi Musah,
I am afraid you will never be able to remove ethylene glycol under the described conditions (I assume that you tried to use 130 mbar and not 130 bar). At 130 mbar the boiling point of ethylene glycol is around 140-150 oC. To be able to remove at 55 oC you need min 2.6 mbar, but at this pressure you will not able to remove anything from ethylene glycol in rotavap. You need almost one magnitude lower pressure (e.g. < 0.5 mbar) what is difficult to reach in rotavap. But, if you can set this low vac, put a piece of paper towel tightly (but not very tightly) onto the vapor tube (or to the anti splash protector) otherwise the condensed ethylene glycol is flowing back.
I do not agree with Pier Luigi because usually the filter paper is not enough to filter solids after ball milling.
Try to centrifuge the mixture. Or, if that is not in hand, perhaps glass filter (PO4) without using vacuum might be applicable. But, I assume that it is better to dilute your suspension with MeOH (or EtOH) to reduce the viscosity. Of course if MeOH (or EtOH) does not solubilize too much ytterbium oxide. Repeated filtration might be necessary. If you add vacuum the very fine solid might go through the sintered glass and the filtration speed can also be decreased considerably after few mils (even to zero).
Otherwise, please find some useful links below:
1. for finding boiling point/pressure diagram, you can make a search in google images
2. for BP estimations you can use this link: http://www.trimen.pl/witek/calculators/wrzenie.html
or this: http://www.calctool.org/CALC/chem/substance/boiling
or this: http://www.sigmaaldrich.com/chemistry/solvents/learning-center/nomo-assets.html
or this: http://vle-calc.com
3. for the viscosities read this publication: https://archive.org/download/conductivityvisc00guyjrich/conductivityvisc00guyjrich.pdf
or this: DOI: 10.1021/je990059p
good luck,
Laszlo
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