# How to separate butane from air?

I work in a manufacturing company specializing in polyethelene foam and I have been struggling to separate butane from air in our warehouse during curing period where all the butane gas used to make our product is just released in the air. I have been thinking of ways how to separate and recycle the butane? Can someone help me?

• Wait... butane in the air, just like that? Well, hopefully nobody is smoking in the warehouse. As for the separation, I'd probably rely on freezing out the butane (it has boiling point about $0^\circ$C). – Ivan Neretin May 18 '16 at 7:46
• Are you sure there is enough butane to make recycling worthwhile? – matt_black May 18 '16 at 9:07
• The noble gases tag doesn't seem to be right for butane. And I'd echo matt_black...quantity available to capture could be very small. – Robert de Graaf May 19 '16 at 11:57

Butane has pretty high boiling point (around $\ce{0 °C}$). This means, that just cooling air to $\ce{-30 °C}$ should condense a lot (if not all) of butane from it.