Natural Science Forum / Chemistry / Organic Synthesis / September 2005

You can make anything from anything - assuming you have the right elements
and a shed load of energy.  Sadly there is not enough energy from solar to
do that - if there was that much energy then why have the chimney in the
first place - it's usually for a boiler - so just use eletric heating...

Well that would solve all the world's problems if it were possible in
any thermodynamically practical way...CO2 and H2O are combustion
products, in other words hydrocarbon -> CO2 + H2O is exothermic.  Going
the other way requires a very large net input of energy, solar likely
won't cover it (don't forget the thermodynamics and economics of
producing solar cells).  Hydrogen needs to be obtained from somewhere
at another energy loss, either water electrolysis or dehydrogenation of
fossil fuels.

There is ongoing research to find a magic catalyst that can accomplish
reduction of CO2 with H2.  Notably, superacids which stabilize
carbocation intermediates.  Good luck ever seeing SbF5 being put into
plant use.  And then there's still the hydrogen problem.  See the
homepage of the Loker Hydrocarbon Institute at USC.

On Tue, 19 Jul 2005 11:14:35 +0000, rekuci wrote:

Thanks, I took a look at the Loker Hydrocarbon Institute (page 5 is
interesting). I begin to understand the difficult energy requirements of
the process. I'll try to stay interested though. There are some situations
I can think of where the thermodynamic expense isn't really an important
obstacle, (eg propellant synthesis for Mars return missions).

Of course, there is always nature to do it for you via trees and
plant-life.

Producer gas shift using a mixture of CO2 is possable and to note from
another post biological reactor beds that produce various products can
consume the stuff but My main question is what exactly are you shooting
for?  As far as I know methanol can be produced via CO2  and H2 using
standard catalist (no Idea about efficenty) I have worked on electrical
methods for reducing CO2 with at least a little success I'd love to
work more on the idea if their is money involved (I'm way too broke to
even consider digging into it again.)

probably the most practical way to get this stuff to work is to jack up
the amount solar available, possably with an orbital solar mirror so
your solar can get nice vertical mid-summer high noon solar.  But then
with the same solar could shoot right down into a city in winter
turning off lights and furnaces and the CO2 would never have to be
generated. not sure how to make a buck off of that but ????

With the advances in DNA engineering one might alter some plankton to float
at the surface of the oceans which would produce some form of "oil" by
photosynthesis.

And make it bitter tasting to dissuade pests from eating it.

This could be harvested by vast "refinery" ships into chemical and fuel
feedstock.

Also this would soak up vast quantities of the atmospheric CO2

I rather like the concept and actualy several variates of algie for
droplets of oil inside or produce potentaly usable feed stocks.
However two magor problems that have to be over come are that the CO2
ends up disributed in the atmospere and the low concentration results
in limited reaction rates,  this could be over come by keeping the
concentration higher but the current infrastructure would have to be
revamped.  The second is that the algie does not work for free, as soon
as the sun goes down the algie begins to burn up oxigen and eat up the
materials it made so some way would have to be found to keep the lights
on and keep the bugs from laying down on the job and eating the profits.

As in land plants there would be a net increase in the product "oil" and
this could be harvested.

As an example I refer to the old Rape Seed plant, the oil of which contained
a toxic-to-humans C11 hydrophobe; but this was genetically engineered to
eliminate the small quantities of the C11.

Now this Rape Seed plant is known as "Canola" and is harvested
(mechanically) in vast quantities in Australia and elsewhere.

The world's oceans represent a vast "hydroponic soup" for the growing of
some oil-containing floating weed, and this might be as voracious as the
notorious Water Hyacinth and so just beg to be harvested and processed.