Degassing Deep Dive - Part 2

Degassing Deep Dive: Part 2

What is a degas pass?

Ok - so now you have a feed material that has a super-volatile component. It has to be removed before you can do you high vacuum distillation on the wiped film still.

Well - one option is to actually use the wiped film still to remove the trace light. It doesn't have to be a large percentage for the still to be used to degas the material. Wiped film stills are incredibly efficient at removing trace lights in a degas pass.

A degas pass consists of a low vacuum pass at mild temperature, with the state goal of removing the volatile material.

In practice, it is generally run at about 30-60 Torr and 75 - 125°C. But the vacuum level can range as low as a couple of Torr and sometimes as high as 200 Torr. The same way, the temperature could be as low as room temperature and perhaps as high as 200°C.

It all depends what you are removing. Let's say you are removing 1% water. A vacuum of 40 Torr and a temperature of 100°C will ensure that the water is fully removed, perhaps as low as none detected.

I've used these types of conditions hundreds of times to prepare a feed material for the next pass through the still that does not bubble, spit or cause the vacuum level to drop. This approach will take trace lights (0.1 - 5%) and fully remove them, so the next pass through the still will be unimpeded by super-volatiles.

The next post will compare using a still to degas the material to using other equipment like a rotovap or a reactor.