Syntin for the second stage of Falcon 9?

[Proponent]

Syntin, by the way, is just three cyclopropane rings stuck together, with a methyl group thrown in.  Bruce Dunn found lox and cyclopropane itself to be an excellent propellant pair, offering an I_sp a couple of seconds better than lox/methane's and a bulk density of 969 kg/m³, which is closer to lox/RP-1's 1030 kg/m³ than to lox/methane's 828 kg/m³.  It's only slightly cryogenic (NBP is 240 K), and its viscosity at NBP is just 0.16 cP (see attachment), only a bit higher than methane's 0.12 cP and much lower than RP-1's  3.3 cP.

The thing is that cyclopropane is very expensive.  Even when it was used for anesthesia (showing that there is no serious toxicity problem), it was not cheap.  Could anyone find a cheap way to make cyclopropane?

[WmThomas]

It's time to end this discussion. The OPs idea has been soundly criticized. We're done.