Triethylborane −20 °C (−4 °F): It looks like something that you could find in Titan, but I don't remember reading about that. The structure is not so weird, and there are some similar molecules with nitrogen instead of boron. I don't remember massive natural production of organic molecules with boron, but boron chemistry is very weird and well above my chemistry level.
Silane 21 °C (70 °F): It would be more strange to have too many organic molecules with silicon.
Phosphorus (white) 34 °C (93 °F): I don't think it's stable enough to be acumulated naturay. It's too energetic and I expect it to react with some of the molecules in Titan.
I don't expect a fast oxydation that set them in flames, but I expect them to fell what you would feel if you take a bath in bleach.
To get a nice fire instantly on Earth, you need something like the substances in https://en.wikipedia.org/wiki/Autoignition_temperature . The ones with low temperature are
Triethylborane −20 °C (−4 °F): It looks like something that you could find in Titan, but I don't remember reading about that. The structure is not so weird, and there are some similar molecules with nitrogen instead of boron. I don't remember massive natural production of organic molecules with boron, but boron chemistry is very weird and well above my chemistry level.
Silane 21 °C (70 °F): It would be more strange to have too many organic molecules with silicon.
Phosphorus (white) 34 °C (93 °F): I don't think it's stable enough to be acumulated naturay. It's too energetic and I expect it to react with some of the molecules in Titan.