Methane would be made by combing hydrogen and CO2 together by heating it up and pressuring slightly and in the presence of platinum. It would combust with lots of pressure, smoke and a small amount of fire. Methalox would be made by pressuring methane and oxygen. It would act like rocket fuel and burn slowly with lots of fire and pressure. Also it can be turned liquid by pressure. Methane can become liquid Methane through cold. Abbreviations would be Mthe and Mlox
Here are my ideas:
1) Methalox is just liquid methane + liquid oxygen, it shouldn't be a separate element.
2) We already have high performance rocket fuels like stacked OIL, FIRW, COAL, etc. I think that methane should give even higher pressures (similar to C-5), high temps, and more reactions.
3) About reactions, how about (these probably aren't very realistic, just some ideas):
MTHE + really high temp + low pressure -> BCOL/HYGN
MTHE + SPRK -> FIRE + lots of heat and pressure
MTHE + PTNM + HEAT -> OIL/DESL + HYGN
MTHE + OIL + HEAT - (low chance) -> MWAX
and of course MTHE would release lots of heat while burning.
Thanks! But I found out that there is someone else with similar ideas to me. https://powdertoy.co.uk/Discussions/Thread/View.html?Thread=26824&PageNum=0#Message=325704
GAS exists
IRL rocket fuels do not propel the exhaust gases in one direction on their own, that's the nozzle's job.