Entrainer for THF/Water distillation

[cdev]

I am looking for an entrainer to separate THF and water. I am aware that Pentane is used in certain applications however we are looking for an alternative entrainer. Any suggestions?

 

Do you mean Tetrahydrofuran? Is one species
minimal (say less than 10%) or are they about
the same? Do you want to recover the water or can it be wasted? If mixture is mostly THF then passing it through salt (NaCl) will make a THF layer that is about
2.5% water (The bottom layer is salt water.)
I suppose you mean that pentane would entrain
THF in the top layer of a decanter. I have experience using toluene (more toxic than pentane however).
I would imagine that THF would prefer many organics over water.

 

[25362]

Sorry for my delayed comment. It happens that I adhered to the Eng-Tip forums only of late.

One technical book says that THF and water form an azeotrope with composition sensitive to pressure. So they can be effectively separated in a two-stripping column system operating at two pressures: the atmospheric, taking water as a bottom product using stripping steam as heating medium. The condensed overhead stream from this tower, serves part as reflux, the remainder is sent to the middle section of a pressure tower heated with a reboiler. The bottom stream of this column is pure THF, the top stream is condensed. Part of it is used as reflux and part re-sent to the original blend of THF and water. The pressure tower works at about 7.5 atm.
Although not exactly satisfying your request, I hope this message helps.

 

[PierreSTRAUCH]

A good alternative to the pressure swing distillation will be a combination of a distillation and vapour permeation (pervaporation). At atm. Pressure the azeotrope will be around 94% THF / 6% Water.
90% (10% Water) can be reached with a simple distillation. The dehydration from 90% up to 99.5% is easy by pervaporation.
a general info is available under:

http://www.sulzerchemtech.ch/eprise/SulzerChemtech/

Sites/products_services/pervap.html
Feel free to ask for more info or sizing details.
pierre.strauch@sulzer.com