Apologies in advance for not being able to trim this post down to
a more manageable size, as it is a compilation of prior postings
and is still a work-in-progress.
In chemistry, *catalysis* is the acceleration (increase in the
rate) of a chemical reaction by means of an surface interface or
dissolved substance, which is itself not consumed by the overall
reaction, or at least is easily reconstituted.
In 'chem 101' the student is taught that a catalyst decreases the
activation energy gap which must be overcome in a chemical
reaction, but cannot increase the net energy available, because
the rate of both the forward and the reverse reaction are equally
affected. The net free energy change of a reaction is the same
whether a catalyst is used or not; the catalyst just makes it
easier to activate. At least that is the "mainstream spiel:" zero
OU from chemistry !
The SI derived unit for measuring catalytic activity is the
"katal," which is moles per second. In a few cases the increase in
reaction rate is by a ratio of 10,000,000 to one. Naturally, the
free-energy enthusiast has been probing all aspects of this for
years, but catalysis 'works both ways' so to avoid the limitation
of an "equilibrium" state - immediate changes must be made in the
reactants, to preserve a more favorable transitory situation.
OK, that is where we stand in general terms going into 2007. But
is there looming, the single exception in all of chemistry to the
laws of thermodynamics forbidding that a string of complementary
or sequential [chemical only] reactions which cannot be gainful ?
IOW - in all of nature - if there is any singularity where the
thermodynamics of a reversible reaction are very slightly
asymmetrical, to the tune of even a fractional eV; which energy
might be exploitable by providing a high reaction rate? The idea
is that the energy deficit is eventually replenished by either ZPE
or the Dirac epo-field, probably in the form of the 6.8 eV
ionization potential of virtual Ps. But that is fodder for another
day. If there is a lone chemical singularity, it will likely
involve both 'autocatalysis' and 'superoxidation,' and to that
end, consider the following complex situation, which admittedly
contains some "problems", as it is not a refined hypothesis yet.
Catalysts, as mentioned, participate in reactions but are not
reactants except in "autocatalysis," where the product of a
reaction accelerates the same reaction. Naturally if there was
even a very slight asymmetry in reversible thermodynamics, then
autocatalysis could result in a chemical-only chain reaction - to
multiply an imperceptible gain into a useable gain using its own
reiterated asymmetry. I suspect that 99% of participants of this
forum have written this possibility off as impossible. As had I
until recently.
OK -the above is the 'preamble' (pre-ramble) and I hope the stage
is set for this revision of an old posting on the subject of
peroxide electrochemistry, which has been revised slightly. The
original title of this was: "242"... 242 is an important number in
nature and for alternative-energy schemes, at least when it refers
to nanometers. Google "242 nm" and you will get almost 50,000
hits.
UV light - ultraviolet radiation at wavelengths smaller than 242
nanometers has the property of instantly splitting molecular
oxygen (two atoms bonded together) into atomic oxygen (individual
atoms of oxygen) with high efficiency. This particular UV photon
has a mass/energy of 5.1 eV. Solar photochemistry (and life on
earth) depends on this reaction and the regular ozone cycle - in
the upper atmosphere:
http://www.ccpo.odu.edu/SEES/ozone/class/Chap_5/5_2.htm
In nature, this is the start of a chain of events which functions
to keep harmful UV from reaching the earth's surface - but the
process can also be "engineered" to occur on demand in a reactor
small enough to be carried "under the hood". Biomimicry revisited.
It is not efficient to produce UV light from grid electricity, but
there are certain surface catalysts, which will operate on O2 in a
similar fashion - in order to provide a net energetic effect equal
to 5.1 eV, in order to split oxygen. For instance, manganese oxide
is the preferred oxygen catalyst for all of organic life. Perhaps
it is a singularity in itself. The MnO family operates by
shuttling oxygen ions back and forth in its outer shells, and this
is possible because of its very large number of facile oxidation
"states" -- *eleven in all.*
Of particular interest is the transition between the MnO2 and MnO4
states in an acid solution where the effective "band gap" so to
speak, is slightly more than the necessary 5.1 eV. The band gap in
semiconductors (or energy gap) is the energy difference between
the top of the valence band and the bottom of the conduction band.
Catalysts bear much similarity to semiconductors in
electrochemistry.
There is a chain of coordinated events which is necessary -
following the moment when an energetically excited oxygen atom has
been "unpaired" from the O2, which will get to the point when that
energy can be both OU and useful. When the photon of 242 nm or
less [or band gap] encounters molecular oxygen and splits it,
either unpaired atom will quickly bond with other molecules to
form three-oxygen molecule, ozone - O3. Following this - in the
right circumstance (proximity to water) O3 will interact and
immediately form hydrogen peroxide - HOOH - which is relatively
more stable than ozone, but relatively less-potent as an oxidizer.
H2O2 is one of the most powerful oxidizers known - stronger than
chlorine but not as strong as ozone; having an oxidation potential
of 1.8 eV versus 2.1 eV for ozone. Otherwise, of course, ozone
would not combine with water so readily in order to form peroxide.
That reaction is known as *superoxidation* and can be speeded up
greatly though catalysis. Superoxidation is the key to finding a
thermodynamic asymmetry.
However - and also through catalysis but employing the very same
surface catalyst, H2O2 does not *go back* to ozone ! as expected
but instead will be converted into two hydroxyl radicals (-OH)
each with far higher reactivity (2.8 eV) then the progenitor
molecule. That part of the chain of events is potentially gainful,
and depends solely on catalysis which is not-exactly reversible.
Therein lies the small window of opportunity for finding OU in
water-air electrochemistry, with or without solar UV light.
The bottom line is that the 2.1 eV oxidation potential of one
ozone molecule is converted into two 2.8 eV (O.P.) hydroxyl
radicals, for a net gain of 1.4 eV by going though the circuitous
route of peroxide catalysis. The initial 2.1 eV oxidation
potential ozone required a 5.1 eV photon and so was not at all
gainful. In fact the COP was surprisingly low for that step. But
the original photon, at least in theory, can give us two free
oxygen atoms, not one, and IF both of them combine into two
molecules of ozone, and then both ozone molecules then form two
HOOH molecules ... which are catalytically split - then four
hydroxyl radicals will be the result [on paper] and consequently
the potential COP of the entire reaction could be as high as:
COP = 11.2/5.1 = 2.27
Pretty significant, but admittedly this will never happen so
cleanly.... and admittedly oxidation potential is NOT exactly
convertible into net energy directly. Nevertheless, this
reversible chemical situation, involving superoxidation and
catalytic "see-sawing" between: H2O +O <--> HOOH appears to be
a singularity.
Arguably, it is the only situation in all of nature where one can
show a potential "net gain" in a sequence of probable reversible
reactions, which gain is due to catalysis [in a way] but in which
the reverse-catalysis is not favored over another branching
possibility [and premised on everything in the intermediary stages
happening at high efficiency].
Normally the rule of thumb about catalysis will hold - that is,
that catalysis cannot supply "net energy" but can only speed up
the *reaction rate* in situation where there are energy gaps, or
entropic deficits BUT in this one instance, superoxidation, the
hydroxyl radical is so favored [and ubiquitous in nature] despite
its enormous oxidation potential, that it seems unique.
A singularity? (certainly a mouthful of word-salad, and before
breakfast even ;-)
Jones
