In article , John
Michael Williams wrote:
(Don Klipstein) wrote in message ...
In , Bill Sloman wrote
in part:

I had to work through the equations many years ago for an experiment
intended to monitor the process in which one of the "Dewar benzenes"
converted itself to normal - Kekule's - benzene, which is an
enormously energetic process, involving about an order of magnitude
more energy per molecule than you get out of TNT and PETN. I really
didn't want to blast my experimental apparatus to smithereens.

When I went through the calculations with my supervisor, he pulled a
very long face - the motivation for the experiment had been some
unexpected flashes of light seen when a dumb organic chemist had
released small drops of liquid "Dewar benzene" into a hot cell, and my
calculations made it clear that the flashes of light were just thermal
radiation from a hot plasma, rather than fluorsecence from from an
electronically excited state of Kekule benezene, which is what my
supervisor had been hoping for ...

For the difference between Dewar benzene and Kekule benzene see

http://www.chemsoc.org/exemplarchem/...enzenering.htm

If this produces anything near 10x the energy per weight of TNT or PETN,
then a version with controlled reaction rate would make one heck of a
rocket propellant.

I thought the ultimate energy per mass was magnesium and oxygen (or was
it beryllium and oxygen?), just a few times as much energy per mass as TNT
and not good like usual rocket propellants for producing gas to use as
rocket exhaust.

It depends on the electrochemical gradient, I think.
Hydrogen burning in fluorine probably produces more combustion
energy than anything else, per unit mass.

That one is up there, but let's check heat of formation...

HF gas: 63.991 KCal/mole, 3.19955 KCal/gram

MgO: 145.76 KCal/mole, 3.644 KCal/gram, but with no gaseous output.

I am surely skeptical of changing one isomer of a molecule to another
producing even comparable energy to, let alone more energy than
decomposition of a similar or somewhat greater mass molecule of high
explosive.

I share this skepticism. Burning TNT probably would produce 10x more
free energy than detonating it.

The usual high explosives contain nitrate or nitro-group molecule
portions, or other oxidizers.

TNT does not have enough oxygen in its nitro groups for complete
combustion, so you get some more energy burning it than detonating it.
On the other hand, nitroglycerin and RDX have enough oxygen in their
nitrate groups for complete combustion.

- Don Klipstein )