I have instructions for extracting pure essential oil from plant material using butane. The problem I have with it is that at the end, the butane is vented. I just don't feel right about venting unburned hydrocarbons into the atmosphere. I've been looking at glass lab equipment (distillation tubes, connectors, etc). I have no background in chemistry, but it seems to me it shouldn't be too difficult to put something together using standard glass lab equipment to capture, distill and reuse the butane.
Butane boils at 31 degrees Fahrenheit and is heavier than air. At the end of the process, the oil is scraped from the bottom of a drying dish.
Does anyone have any suggestions on how to put something like this together?