grundig im not sure what your talking about. I dont see how a chemicals state whether its liquid or gas would have any affect on it's purity. Take butane gas and pressurize/freeze it, and you have liquid butane. Why would it's chemical composition be any different.
When it has a melting point of -138.3 C I dont think anyones going to be freezing it with conventional methods so the guy with the bike pump can probably stop now.
at room temperature, butane is a gas. but as with any gas, it'll turn to liquid if it's pressurized enough or if it's frozen beyond a certain point. (below -138.8C for butane) and then it'll turn to a solid if it's pressurized or frozen even more than that.) most gases like oxygen would need a much much much colder temp. or else much much much more pressure to become a liquid, so that's why you never see them in liquid form. the only way to make the butane stay liquid without boiling would be to make the bho in a freezing cold room that's under -138.8C, or to make it in a room that's pressurized just as much as the inside of the butane can, but im pretty sure that would kill you if it was even possible