[rolnor]

If its possible to make stearic acid from octadecane it would be easy to make a triglyceride from this. The lipid could be used as nutrition in case of a global atomic winter if Putin gets more trigger-happy. I dont see much about this on the net but it is probably well studied. Has anyone of you studied this field?

[rolnor]

That goes for any fatty acid, maybe palmitioic acid would be fine, hexadecane is a component in kerosene. Glycerol is probably also available via petroleum?

[Enthalpy]

Hi Rolnor,

instead of hexadecane, which doesn't abound in crude oil, I propose to start with ethylene, obtained by cracking of crude oil, or by controlled pyrolysis of natural gas.

Refineries obtain routinely 1-alkenes from ethylene, for instance a mix of C₁₂, C₁₄, C₁₆.

Hydrolyse the alkenes to 1-alcohols. Oxidise the alcohols to carboxylic acids.

I don't expect any glycerine in crude oil. It's a mass by-product of biodiesel and soap from vegetable oils, few people search for alternatives. But I suppose it could be synthesised if needed
https://en.wikipedia.org/wiki/Glycerol#Synthetic_glycerol

I just wonder if humans need triglycerides. Maybe simple esters of a fatty acid and a fatty alcohol can be digested. Glycerine and bigger polyols feed us too, as does ethanol with drawbacks.

And: unsaturated fatty acids would be healthier, but only if cis.

[rolnor]

Thats a good idéa. One problem with glycerine is that its a laxative. I dont know how the body reacts when you ingest large amounts a fatty acids or simmilar, that could be a big problem, you need something thats good food. But if the sun is blocked in a nuclear winter situation you need to make food from something abundant that is not depending on the sun to grow. I think petroleum i best, you need large amounts. Some lipids are essential and this is important. Also some amino acids are. If they have not allready done so, I think the army/government must look inte this research area, this risc has been present since the 1960s and has increased dramatically because of Putin and the attack on Ukraine.

[billnotgatez]

By the way
@Enthalpy
discusses topics similar to this plus more at
https://www.chemicalforums.com/index.php?topic=111032.0

[Babcock_Hall]

One of the essential fatty acids is alpha-linolenic acid and another one is linoleic acid, which is a precursor to arachidonic acid.  It is tempting imagine packaging these two in a phospholipid with choline as a head group, because choline is a vitamin-like nutrient.  Just thinking out loud.

[rolnor]

Great idéa. I have a hard time to understand why this is not a very hot research area. What are we going to eat when the sun is blocked? Are we going to pretend that this problem will never appear? I think its naive. Trump is already responding to Putins nuke-threat with "The US has much, much better weapons".  Hardly feels reasuring. Whe should be prepared for this possibility. Even if the risc is still low.

[Enthalpy]

One of the essential fatty acids is alpha-linolenic acid and another one is linoleic acid [...]

Big difficulty, the essential nutrients. Bringing the calories is relatively simple, but over years, many compounds are vital, and these are much more difficult to mass-produce without biology.

[Enthalpy]

Glycerine has no good synthesis because it's a massively available by-product in present times, by for instance pentaerythritol does have a good path.

In itself, it might be food.

It might also lead to tetraglycerides. Synthetic fatty acids can be shorter to compensate their number. I have no clue how healthy tetraglyceride food might be.

[Enthalpy]

Even if photosynthesis is blocked, Mankind will access a huge amount of dying and dead biomass, complementing gas and oil.

Fungi might provide some nutrients. Zero calorie as I understand, but they provide essential metals. Alas, they concentrate radioactivity too, needing spared locations.

Grass and wood to human food isn't immediate, but for instance methanol from pyrolysis can become pentaerythrose and pentaerythritol, or ethylene and then fatty acids and so on.

[Enthalpy]

[...] Refineries obtain routinely 1-alkenes from ethylene, for instance a mix of C₁₂, C₁₄, C₁₆. Hydrolyse the alkenes to 1-alcohols. Oxidise the alcohols to carboxylic acids.[...]

Alcohols by anti-Markovnikov hydration of alkenes are too expensive. The normal path is hydroformylation to aldehydes. Oxidation provides then the desired acid, reduction the alcohol if wanted.

[rolnor]

Even if photosynthesis is blocked, Mankind will access a huge amount of dying and dead biomass, complementing gas and oil.

Fungi might provide some nutrients. Zero calorie as I understand, but they provide essential metals. Alas, they concentrate radioactivity too, needing spared locations.

Grass and wood to human food isn't immediate, but for instance methanol from pyrolysis can become pentaerythrose and pentaerythritol, or ethylene and then fatty acids and so on.

Very interesting. There will be a lot cellulose then, and from this we could have carbohydrates. Pentaerythritol is promissing, how about chirality, is this important? Can the body digest any enantiomer? Glycerol is good this way, its not chiral.

[Enthalpy]

To my understanding, pentaerythritol has no enantiomers.
https://en.wikipedia.org/wiki/Pentaerythritol
Image pinched there.

[rolnor]

Ha, ha, very sorry, I mixed it up. But is it possible to use use it as energy source for the body?

[Enthalpy]

I ignore that to a high degree of accuracy. But maybe someone here knows it.

The dietary general idea is that polyols contain the usual amount of calories, while inverted sugars don't. To my taste, dietary isn't reliable enough.

One other disturbing thing: muscles can feed on fatty acids, but the brains only on glucose made by other organs from glycerine. No idea what compounds other than glycerine fit that task. Because, if the brains is starved, feeding the other organs is useless.