Nanodistilling

Athanasius Kircher (1602-1683) has been described as “strange and rather fantastical” (Forbes, R. J. E). He is a 17th century Jesuit and professor of mathematics and philosophy. He published the Mundus Subterraneous, his most important work, towards the end of his life. The 12th book of this work describes distillation, and includes per ascensum, per descensum, and per latus concepts. This book suggests theory only and not a reduction to practice. It is from his drawings that we find the esoteric ad latus or per latus apparatus, that is, a distillation “to the side” or “from the side”.

Interestingly, glassblowers from the 18th century, who likely learned their skills from the Ars Vitaria, created a per latus apparatus which survived. The Munich museum is purported to have this very apparatus:

Since we have no information on how this works, we built a modern-day version from borosilicate glass, thanks to the skill of Q-Glass in Towaco, NJ!

Our modern apparatus is simply a high-conductivity path for hot vapors, starting at the left in the above picture, and moving towards the right, while condensation occurs along the path. At first glance, it is a “short-path” condenser with multiple receivers along the path. As the hot vapor moves into the manifold, it is condensed on the air-cooled outer walls. We included drip tips above each receiver to help aim the condensate drops and provide more surface area.

Like our other ancient stills, the boiler is driven slowly and carefully to create a slow-moving front. Hot vapors are moving through a thin film of condensate, providing some possibility of vapor-liquid exchange. The final receiver at the right has an air vent (cannula) to allow pressure relief. We have found that an 85’C setpoint on the boiler for a 40% aqueous ethanol solution is about perfect for operation.

As with our other stills, we have applied simple liquid crystal thermometers (60-90’C range) on top of the manifold to monitor the temperature of the hot vapor front as it moves from left to right.

After about an hour-long run at the setpoint, each receiver now has condensate. As expected, the volume collected decreases going from left to right (away from the boiler). Also as expected, the alcohol purity increases from left to right. Some rectification is occuring, as the leftmost receiver is at 162pf while the fourth receiver is at 181pf ! This is from a starting wash of 80pf. There was not enough condensate in the 5th and in the final receiver to measure on this run, but we can make a prediction given equal distance along the path.

Simple linear regression indicates we should hit 186pf at the 5th receiver, and the azeotrope at the end receiver. The value of 186pf is expected based on actual data from the Barchusen, Booerhave, and LeFevre apparatuses.

Well, we need some more time to perform a couple of more experiments here, so please stop back soon as we update this page! Perhaps Professor Kircher was not so “strange” after all!