Enviorosafe, Duracool, and a bunch of others are hydocarbon based.
Translation-- they are Butane/Propane. I have seen the claims of
drastically reduced electric consumption, and better gas mileage in the
case of auto a/c. I don't believe any of that, but I have Duracool n an
old Suburban and it has worked ok for several years. ( A friend bought
some for a car he was going to use it in, and sold the car without ever
messing with the a/c, and gave it to me. When I had to replace a leaking
hose on the Suburban, I had it and decided to give it a try.) Larry