How does the "kreosan" Coca-Cola rocket work?
Here's a paper written about propane forming small ice crystals when sprayed into a cloud of water vapor: James R. Hicks and Gabor Vali, J. Appl. Meteor., 1973, 12, 1025–1034.

I'm no expert, but I'm guessing the propane forms small ice crystals as it passes through the Coca-Cola, and when flipped, the Coca-Cola warms up the liquid propane, which causes it to expand as it travels upwards. This provides an immense surface of nucleating sites, similar to a Mentos reaction, but with millions of microscopic Mentos (this means larger surface area). The pressure waves caused by the violent nucleation further drives the reaction, as the liquid propane expands further and freezes more ice crystals and so on. This all happens quite fast, and with one easy way out, everything shoots out the mouth of the bottle.

Of course this was written by a Materials Engineering undergrad, so don't take this explanation too seriously.