[lukas.stib]

Hello chemists,

what procedure and how much aqueous 15% sulfuric acid should I use for the synthesis of ETBE from tert-butanol and ethanol? I think 20 ml. I will use 50 g of tert butanol and according to the stoichiometry I should use 31 g of ethanol, but I will use an excess of ethanol-about 40 g. The mixture should be heated to 40°C, but I do not know how long...
Does ether layer formed on top?

Picture from Wiki.

Thank you, Lukáš S.

[rolnor]

I would use equimolar ratio of the alcohols and small amount of the acid catalyst, the catalyst is not consumed. Then distillation. Maybe 5ml acid to 50ml t-BuOH.

[lukas.stib]

Do you mean 5 ml of acid in an aqueous 15% solution in water, or add without water? In synthesis, they write aqueous. And do you mean distillation now, or heat to 40°C for about an hour and then distill? I think that warming up to 40°C is not enough...

[rolnor]

I mean 5ml 15% acid. If it says 40° in the recerence this is enough. Its not easy to know how long reaction time, maybe 1-12hours? I would try stir over night then distill.

[lukas.stib]

OK, thank you very much.

[rolnor]

It can be good to remove water+acid before distillation, it will probably form layer as you suggest, first separate phases then add some NaHCO3 untill it does not bubble then filter and distill.

[lukas.stib]

OK, thanks ;-). I think this ether don´t distill to dry (peroxides).

[rolnor]

Peroxides form very slowly, you can add an inhibitor if you are concerned.