What range of carbon chain molecules are edible

I was recently reading about ‘coal butter’ which was during ww2, Germany experimented with making margarine out of coal. it worked it just required a lot of energy.

It said they used carbon chains of 9-16 carbon in length. but isn’t that around the same length of carbon chains seen in kerosene? is that the length humans can digest? what happens if you try to make fats that only have five or six carbons or if they have twenty five carbons?

Around the 1930s and 1940s, Arthur Imhausen developed and implemented an industrial process in Germany for producing edible fats by oxidizing synthetic paraffin wax made from coal.[18] The products were fractionally distilled and the edible fats were obtained from the C9-C16 fraction[19] which were reacted with glycerol such as that synthesized from propylene.[20] Margarine made from them was found to be nutritious and of agreeable taste, and it was incorporated into diets contributing as much as 700 calories per day.[21][22] The process required at least 60 kg of coal per kg of synthetic butter.[20] That industrial process was discontinued after WWII due to its inefficiency.

Let’s see, olive oil, typically consists of oleic acid triglycerides, with some linoleic acid and palmitic acid thrown in. Both oleic acid and linoleic acid are C18 while palmitic acid is C16. For simplicity, let’s say they’re all C18. Now the oil is in triglyceride form, which is three fatty acids linked to C3 triglyceride. So that’s 3 x C18 + C3 = C57. Other vegetable oils have a similar composition.

Dietary fats all have a few fiddly bits at the ends that are not typically found in petroleum. I think those are what makes the difference in digestibility.

Yep, those fiddly little bits make all the difference. I’m strictly a layman when it comes to biochemistry, but I’ve always been fascinated by things like:

Sodium: an extremely volatile metal that ignites violently when it comes in contact with water.

Chlorine: a highly toxic element to most forms of life. Extremely caustic in gaseous form.

1 atom of Sodium + 1 atom of Chlorine = Sodium Chloride: a electrolyte that is essential for complex life, and makes food taste great!


LSD and MDMA (Ecstasy/Molly): two mind-altering drugs that have extremely different effects on the human mind, but their molecular structures are mirror-image isomers of each other.

The fiddly bit on a fatty acid molecule is a carboxyl group -COOH. It’s what makes a fatty acid, well, an acid rather than a run-of-the-mill hydrocarbon. It’s where beta oxidation starts eating away at the long carbon chain, converting the fatty acid into carbohydrate. It also allows multiple fatty acids to be aggregated into micelles, for transport via the bloodstream and storage in adipose tissue.

The wikipedia article on fatty acids has links to articles on various ranges. Apparently extremely long chains can’t be used directly by the mitocondria, but (I only checked the far ranges) the rest can.

On the short end of the spectrum is ethanol at C2H6O. I can’t think of anything shorter.

No surprise you’d be the one to propose that particular substance. :wink:

Taking both at once is called candy flipping though I doubt whoever coined the term had the molecular structures in mind.

Very long chain fatty acids can still be broken down by peroxisomes

The acid equivalent would be acetic acid CH3COOH, aka vinegar.

This may not be correct.

There is always metanol. A bit neurotoxic, makes you blind, but apart from that, perfectly edible. We even make it endogenously ourselves, says Wikipedia:

The mean endogenous methanol in humans of 0.45 g/d may be metabolized from pectin found in fruit; one kilogram of apple produces up to 1.4 g of methanol.

Ya, that was the part I was thinking of when I couldn’t think of an edible chain shorter.

One or two gram should be OK. Don’t do it every day, though.
And methanol with an “h”, sorry.

I have one word for you: Hydrogenation

It has a huge impact on the properties (especially viscosity) of hydrocarbons.

I agree, and the Germans added those oxygens and hydrogens to the end synthetically.

But I don’t understand why they only used carbons in the 9-16 carbon range if humans can eat carbon chains with a -COOH group on the end of a wide range of lengths.

Also this made me think of what humans could do to survive if a meteor hit, or the sun was blocked out for another reason. Making edible margarine out of coal (rather than plants) is an interesting concept.

The process is pretty energy intensive, so wouldn’t you be better off using that energy, however you are generating it, to create artificial light to run greenhouses?

You could even save some energy by only using the wavelengths of light that plants actually use for photosynthesis, since much of the visible spectrum is wasted.

I am not sure about the energy demands of the two processes. But its interesting think of how we could feed ourselves as a species if we lost the ability to perform photosynthesis with natural sunlight.

I knew growing crops with artificial lights was an option. So is growing large vats of bacteria or algae with artificial lights to produce sugars and proteins. But I didn’t know we could extract edible calories directly from fossil fuels.

Wikipedia said

The process required at least 60 kg of coal per kg of synthetic butter

a kg of coal has 7000 calories of energy, and so does a kg of margarine. So thats not a very good energy output, but the world does have about a trillion tons of coal.

Perhaps the choice of carbon chain length range was done to control how solid or meltable the margarine was?

Huh, I never thought of it that way before, but I suppose that acetic acid is actually a fatty acid.