Is there any food (with positive energy value. so don’t say water) that is made from inorganic compounds (that is, not coming straight from biological matter, organic compounds produced from inorganic compounds being allowed)?
Would it be feasible (technically possible, not necessary economically viable) to make one?
Finally! I keep telling the vegeterians: how come you don’t mind killing plants to eat them? We should all eat mineral food only.
I’m sure it would be possible to construct simple sugars and fats from scratch in today’s advanced labs. The more esoteric fats as well as amino acids / proteins may be problematic in reasonable quantities, though. And the whole thing will be super expensive.
Would it be possible to refine food oil out of crude oil?
Well, technically oil is organic matter, but anyway let’s allow it too…
Acetic acid was the first organic compound synthesized from inorganic starting material, by Hermann Kolbe, in the 1840s (many people say Woehler’s 1828 synthesis of urea from ammonia and cyanate is the first synthesis of an organic compound from inorganic starting material, but I must note that his cyanate was derived from organic sources. Kolbe’s carbon was ultimately, I think, from graphite). Acetic acid would not obviously be a complete diet, but it does play a role in the metabolic cycle, and I think it’s energy positive.
Doesn’t urea count anyway? I mean despite biological sources, all substrates being technically inorganic compounds?
In principle you can synthesize any molecule that has nutritive value from “inorganic” sources, and such molecules could be put together into a nutritionally complete diet. In practice it would be prodigiously expensive and inefficient to do so.
Yes, it counted at the time, because Wöhler had shown, for the first time that a recognizedly organic compound could be synthesized from compounds recognized to be inorganic. This showed that there was no special, mysterious component or property that organic substances have that inorganic ones do not. Synthesizing acetic acid by starting from graphite, or whatever, is just Guinness Book of World Records type stuff; synthesizing urea from cyanate was a significant nail in the coffin of vitalism.
Yes, but what’s an inorganic compound? Or better, what’s an organic compound? The best definition I’ve heard is "anything with carbon, with some exceptions). Why is urea an organic compound (carbon bonded to nitrogen and oxygen), but not a cyanate (carbon bonded to nitrogen and oxygen)? I mean, I guess there’s a continuum from pretty inorganic (graphite, carbon dioxide) to pretty organic (sugar, etc.), and I guess you have to draw a line somewhere, but it seems to me that cyanate and urea are pretty close together on that spectrum, and it’s just luck that some 19th century guy decided that the line went between them.
The other question, is can the body derive energy from urea? I though urea was usually a waste product, how we got rid of excess nitrogen.
I think the acetic acid example is much better. Acetic acid is unambiguously organic. Carbon disulfide is pretty darn inorganic. Acetic acid is unambiguously a foodstuff.
One would assume glucose could be made from things like carbon dioxide and water in the lab. I’ve wondered about this in an apocalyptic event like a meteor hitting and blocking out the sun. Would we be able to synthesize calories if the sun prevented regular agriculture from working, or as a way to create ultra cheap calories to help people in famine situations. I have no idea what the price would be compared to the fact that sugar is about 30 cents a pound.
I note that my post #6 only addressed the second part of the OP. Let me address the first part: Is the any food with calorific (“energy”) value that is routinely made from inorganic matter. No. However, there are inorganic substances besides water that furnish necessary nutrients and that are normally prepared from inorganic sources for human consumption. Salt is the most obvious example.
Acetic acid was my first thought as well. You could probably make other alkyl acids, but one would typically start with fossil fuels. If that’s not allowed, you could reduce carbon dioxide, electrolysize water, and use the syngas to make a wide range of organic molecules.
Fats might be doable if you have a way to make glycerol. Carbs and proteins are going to be difficult, although some simple amino acids might be OK.
There isn’t really an official definition, but most I and many other organic chemists would require C-H bonds, which urea does not have.
What mattered at the time of Wöhler’s work was that all known organic substances, up until then, were derived from living sources. Organic or inorganic was not defined in terms of molecular structures (which were very little understood, back then) but by whether or not it was exclusively obtainable from living (or once living) sources. No one had ever seen urea that was not derived from an animal (or plant). By synthesizing it from substances that were understood to be inorganic, Wöhler showed for the first time that there was nothing chemically “special” about organic chemicals, no special “life force” or whatever that they contained. That is why his synthesis of urea is a scientific and historically landmark, while Kolbe’s later synthesis of acetic acid is much less significant.
There is really no doubt that any nutritive organic compound - probably any chemically possible organic compound - can, in principle, be synthesized from inorganic precursors in the lab these days.
That may be a reasonable first stab at a definition for a modern introductory chemistry class (although I think most present-day chemists would probably tend to class such things as urea and CCl[sub]4[/sub] as organic) but it is a completely inappropriate and anachronistic definition to use when considering the scientific significance of the Wöhler (and the Kolbe) synthesis.
Of course the real point is that (as Wöhler’s work was the first to intimate) there really is no principled chemical difference between the organic and the inorganic. We now recognize the distinction as merely one of convenience, not a real difference in nature. (But, in and before the early 19th century, it was widely thought to be very real and important.)
Isn’t that the thing though? Woehler’s cyanate was derived from living sources. Why didn’t he (or others) consider it organic? Probably because it was a salt, and behaved similarly to other unarguably inorganic salts. That is, a chemical definition (this is supposition on my part: I don’t really know why they considered it inorganic).
In any case, I think you’re overstating the importance of the urea synthesis in the decline of vitalism. Pasteur, among others, continued to believe in it well into the 1850’s.
And in some respects, vitalism is very close to being true. Nobody synthesizes acetic acid or urea from inorganic starting materials. Any organic compound you can buy is derived from life. It’s true that we can reduce carbon dioxide electrolytically, but nature does such a good job at something that is very difficult for us to do.
I wouldn’t call carbon tet organic, nor would any other chemist I’ve worked with. Urea at least has both carbon and hydrogen.
But the use is arbitrary, and it has changed both before and after Wöhler. Biological chemistry is chemistry. Enzymes are just fancy catalysts. But the do a bang up job. I would be hard pressed to make monosacharides from carbon dioxide and water, but that doesn’t mean someone else couldn’t.
Both amino acids and sugars can be formed via the Miller-Urey experiment and you could presumably make some kind of soup from the results.
Note though that the amino acids formed are racemic (containing both right and left handed isomers) which are poisonous to humans so you would have to figure out a way to filter for only the left handed amino acids.
OP also asks about synthesizing “energetic” (nutritionally speaking, that is) organic stuffs. That necessarily requires a source of energy to pour into the molecules that we make, which we animals then recover by metabolizing the same.
So the process would need an energy source. If that comes from burning coal, or oxidizing any other organic compound, is that “cheating”? Otherwise, to be really strict about using non-organic sources, we would need to use nuclear (or solar, or wind) power as the energy source that we load into our molecules.
Ultimately, most of our organic stuff originates from raw ingredients (C, H, O) + solar power + plants to do all the photosynthesis for us. This is about as “efficient” as it can get, but only in the sense that it all gets done for us without an explicit investment by humankind. (What did I read somewhere? That algae, among the most efficient of the photosynthesizers, only manages to capture around 1% of incident solar power?)
And agreed, a diet consisting solely of acetic acid would not be adequate, let alone palatable. Man cannot live by vinegar alone.
Using the OP’s idiosyncratic definition of ‘inorganic compounds’ :“not coming straight from biological matter”-
To be sure it’s not from biological matter, the source of material where biological matter is least likely to contaminate would be gases found in space.
Not only can ‘inorganic’ materials by this definition be made, they are naturally occurring. Ethanol has been detected in stellar clouds, and it can be metabolized to produce energy for a ‘positive energy value’.
If you insist including a synthesis step, ethylene is also found in stellar clouds, and catalytic addition of water to it will yield ethanol, which can then be metabolized.
As an aside, the definition of an organic compound I’ve always seen is simply one that contains carbon. (My undergraduate organic chemistry textbook agrees.) I would call both carbon tet and urea organic. We’re not in the nineteenth century to be obsessed with vitalism in our chemical definitions…
The definition I’ve always seen is that an organic compound must contain at least one C-C bond, and must contain something other than carbon as well. So methane, carbon dioxide, diamond, and fullerenes are all inorganic, but ethene, ethane, and ethanol are all organic.