# Entrainers to distill MTBE from Methanol? - Chemical Engineering Question

What have you found to be some effective entrainers to distill MTBE from Methanol, given the azeotropic conditions at 67%. I have tried to simulate 1-butanol, as well as ethanol, and numerous other components although have come up short in distilling with high purity.

• Show what you tried - we appreciate effort... – Solar Mike Mar 23 '19 at 21:46

## 1 Answer

Few points: First off, see if you can figure out a way to NOT use MTBE in the first place since it is not an environmentally friendly chemical.

That being said, in dealing with separating azeotropic mixtures (assume 2 components), as chemical engineers we have a few tools available:

1. Adsorption (such as with molecular sieves)
2. Reaction (i.e. reactive distillation)
3. Using entrainers to adjust the relative volatility of one of the components
4. Adjusting the pressure to shift the vapor liquid equilibrium (VLE). (i.e. distillation under pressure or vacuum)

My hunch is that in practice this particular separation is done using (4). In fact a quick lookup I found a reference stating that distillation occurs in two columns. The first having P = 6 bar, and the second P=12 bar claiming 99% purity.

Try re-running your VLE calculations with these pressures. If we've already solved it without entrainers, then no need to reinvent the wheel. From a cost perspective, you can save on the cost of the entrainer (and future separation) at the cost of operating under pressure.