Common Distillation Problems Part 3

Incomplete Separation

Sometimes wiped film stills aren’t capable of obtaining the purity desired.  Wiped film stills are simple distillation systems. 

This means they do not have any fractionating power. 

Whatever material is volatile at the conditions applied will be collected as distillate, including the impurities that you don’t want in your product. 

In these cases, wiped film distillation might not be able to do what you need it to do.  For example, if the boiling points are closer than 50°C atmospherically, there will be a limit to how pure you can make your product.

However, that doesn’t mean that there aren’t tricks that can be done to try to get the desired purity.  Playing around with temperature, vacuum and feed rate can result in different products, especially in the hands of an expert.

Sometimes you know that this product is made using a wiped film still, but you just aren’t getting the results you need. 

In these cases, please reach out.  I can provide a quick, free review of your process and give a straight answer about feasibility. 

I should be able to tell if the desired separation will be straightforward, impossible or challenging.