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Chemistry Forums for Students => Organic Chemistry Forum => Organic Chemistry Forum for Graduate Students and Professionals => Topic started by: rolnor on March 26, 2022, 07:21:55 AM

Title: Lipids from petroleum
Post by: rolnor on March 26, 2022, 07:21:55 AM
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?
Title: Re: Lipids from petroleum
Post by: rolnor on March 26, 2022, 12:45:39 PM
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?
Title: Re: Lipids from petroleum
Post by: Enthalpy on May 04, 2022, 06:01:53 PM
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.
Title: Re: Lipids from petroleum
Post by: rolnor on May 05, 2022, 02:32:11 AM
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.
Title: Re: Lipids from petroleum
Post by: billnotgatez on May 05, 2022, 01:33:51 PM
By the way
@Enthalpy
discusses topics similar to this plus more at
https://www.chemicalforums.com/index.php?topic=111032.0
Title: Re: Lipids from petroleum
Post by: Babcock_Hall on May 05, 2022, 09:07:36 PM
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.
Title: Re: Lipids from petroleum
Post by: rolnor on May 07, 2022, 04:25:56 PM
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.
Title: Re: Lipids from petroleum
Post by: Enthalpy on May 10, 2022, 07:40:52 AM
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.
Title: Re: Lipids from petroleum
Post by: Enthalpy on May 10, 2022, 07:45:54 AM
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.
Title: Re: Lipids from petroleum
Post by: Enthalpy on May 10, 2022, 08:02:13 AM
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.
Title: Re: Lipids from petroleum
Post by: Enthalpy on May 11, 2022, 07:14:54 AM
[...] 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.
Title: Re: Lipids from petroleum
Post by: rolnor on May 12, 2022, 01:32:10 AM
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.
Title: Re: Lipids from petroleum
Post by: Enthalpy on May 13, 2022, 12:04:43 PM
To my understanding, pentaerythritol has no enantiomers.
https://en.wikipedia.org/wiki/Pentaerythritol
Image pinched there.
Title: Re: Lipids from petroleum
Post by: rolnor on May 14, 2022, 01:06:07 AM
Ha, ha, very sorry, I mixed it up. But is it possible to use use it as energy source for the body?
Title: Re: Lipids from petroleum
Post by: Enthalpy on May 15, 2022, 11:53:32 AM
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.
Title: Re: Lipids from petroleum
Post by: Babcock_Hall on May 16, 2022, 02:39:02 PM
Here are some very general principles.  Some amino acids are glycogenic, only two are ketogenic (leucine and lysine), and some are both glycogenic and ketogenic.  The carbon skeletons of glycogenic amino acids can be made into pyruvate or oxaloacetate, either of which can be converted by liver into glucose via gluconeogenesis.  Ketogenic amino acids can be turned into ketone bodies but not into glucose

Under starvation conditions, the brain uses a mixture of glucose and ketone bodies for fuel, in contrast to its otherwise strong preference for glucose.
Title: Re: Lipids from petroleum
Post by: Enthalpy on September 19, 2023, 05:20:36 PM
Feeding humans from dead, dying or living biomass looks trivial.

Cellulose makes much vegetable material and is a polymer of D-glucose
  Cellulose (https://en.wikipedia.org/wiki/Cellulose)
we know already the enzyme that humans lack to break cellulose to D-glucose, one fundamental source of energy
  Glucose (https://en.wikipedia.org/wiki/Glucose)
so we can just use the enzyme, or some chemical processing instead, to produce D-glucose that we eat. Or?

So would we compete for the unpolluted biomass after a nuclear war? Perhaps not, because the radionuclides with significant life are inorganic: I, Cs, Sr and the others. So we might remove the radionuclides by chemical processing apparatus, perhaps some sort of resin or electrolysis or just precipitation.

Again, providing the calories amount to humans is easy. The vitamins, essential elements and others are more difficult.
Title: Re: Lipids from petroleum
Post by: Enthalpy on September 21, 2023, 02:27:08 PM
[...] radionuclides with significant life [...]
I meant: half-life.

==========

It doesn't need a nuclear catastrophe. Local famines abound at any time. Humans could then feed on cellulose by trees and grass, at least for the diet part that D-glucose can replace.

Must the transformation happen in reactors, or could humans just ingest the proper enzyme and swallow tree dust? I suppose our stomach is too small and simple in comparison with cows.

Hey, I'm perfectly zero on biochemistry, so someone else could usefully enlighten us!
Title: Re: Lipids from petroleum
Post by: Babcock_Hall on October 06, 2023, 11:02:36 AM
I don't see how it would be possible to ingest the proper enzyme and swallow tree dust.  The acid in our stomach might denature this enzyme, and it would itself be acted upon by proteases.
Title: Re: Lipids from petroleum
Post by: Enthalpy on October 10, 2023, 04:52:00 PM
Thanks Babcock_Hall!

Then cellulose must be broken outside our body. It's already done for lactose-free milk and diaries, and for agave syrup.