Sciencemadness Discussion Board

95% Ethanol from E85 Fuel

Keras - 26-2-2023 at 05:27

Folks,

I just bought a flexifuel car running on E85 and I was by the way wondering if anyone had attempted to isolate pure ethanol from this fuel. Summer E85 containing up to 85% ethanol at about 1 €/litre, this could be a highly economical source of C₂H₅OH.

Cheers!

Fery - 26-2-2023 at 10:03

I had the same idea few years ago, using distillation column and adjustable variable ratio distillation head, but did not realize it and distilled fermented apples instead... I hate commercial ethanol available here as it is denatured with methyl ethyl ketone and I use ethanol usually for esters.

Keras - 26-2-2023 at 10:21

Quote: Originally posted by Fery  
I had the same idea few years ago, using distillation column and adjustable variable ratio distillation head, but did not realize it and distilled fermented apples instead... I hate commercial ethanol available here as it is denatured with methyl ethyl ketone and I use ethanol usually for esters.


I’m not certain, but ethanol in E85 should theoretically be water free, although I’m not sure of that.

Fair enough. But butanone should be fairly unreactive to esterification, no? Now I understand that can durably modify the organoleptic properties of your ester.

j_sum1 - 26-2-2023 at 15:20

I am just stabbing in the dark here. But my instinct suggests that separating an unknown mix of organics from your ethanol will be more problematic than separating out water. It helps that your ethanol is reasonably concentrated, but concentration is not the entirety of the problem.

MaeBorowski - 27-2-2023 at 12:36

Fractional distillation, counterflow extraction with some water, fractional distillation again?

Dr.Bob - 27-2-2023 at 13:23

I think it would be a cheap source of poor quality ethanol, suitable for many tasks, but not great for lab use. But it would contain little water if kept tightly closed. But very cheap per liter.

I would think you might be able to repurify it, but likely better to start with some denatured ethanol of higher purity would be easier to clean up, but might still have some water in it. There are some specially denatured alcohol mixtures that are ~99% ethanol.

FrankRizzo - 27-2-2023 at 14:16

There's a glut of cheap ethanol hand sanitizer on the market right now. It would likely be easier to extract from that product.

Fery - 27-2-2023 at 19:28

FrankRizzo that's great idea. Pharma ethanol norms are very strict and its purity superior. I'm not sure but maybe it cannot be produced synthetically (from ethylene) but only bio (fermentation). The origin could be revealed trivially by radiocarbon dating method: bio origin contains exact amount of14C carbon from atmosphere while synthetic only 12C and none 14C (14C carbon decayed during millions of years in oil / natural gas reservoirs underground thus without contact with atmosphere). Maybe pharma ethanol for external use could be synthetic and for internal use (various drops) only bio?
But check the hand sanitizer label well, it is usually isopropanol and only very rarely ethanol.

Keras - 27-2-2023 at 22:54

Hand sanitisers are gels. That makes them quite difficult to process. They might not be 100% ethanol either.

Fuel ethanol has to be water free. Apparently, if the ethanol is mixed with water, the alkane (petrol) and ethanol separate, which ruins the fuel.

I’ll take a crack at E85 later this year (in summer, probably, because E85 is a seasonal mix and contains more ethanol in summer than in winter) and run a TLC. I’ll report here, if you’re interested (though I understand that, outside France and Sweden, E85 is not available in Europe, which is a shame).

Fery - 28-2-2023 at 03:19

E85 is available in CZ too. Cheap.

Keras - 28-2-2023 at 05:08

Quote: Originally posted by Fery  
E85 is available in CZ too. Cheap.


Good to know!
I have further read that the ethanol in E85 was rigorously anhydrous. It might not be the best source of pure ethanol, but it should be a good desiccative agent, though, given the hygroscopic properties of anhydrous ethanol.