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Comment by m463 | Hacker News Reader

"American torpedoes utilized 180-proof ethyl alcohol as fuel for the miniature steam engines that drove them toward their targets."

I wonder if this was by design ...

I think isopropyl alcohol is probably generally available/popular only because it is not drinkable.

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Ethyl alcohol is _cheap_. You literally need just a bunch of sugar, yeast, and a still. Straightforward, low-tech, and safe.

Isopropyl alcohol needs to be synthesized from acetone, which itself is synthesized.

Acetone–butanol–ethanol fermentation was itself a critical WWI technology, as cordite required acetone. That fermentation process requires only sugars and an acetobutylicum strain. The first president of Israel developed this process.

Yes, Chaim Weizmann.

When was this supplanted by the cumene process?

EDIT: this process was developed from 1939-1945.

https://en.wikipedia.org/wiki/Cumene_process

https://shop.tarjomeplus.com/UploadFileEn/TPLUS_EN_2421.pdf

BTW, isopropyl alcohol is industrially produced from propylene, not acetone.

I don't know how the balance broke down during WW2, but synthesis of ethanol from ethylene in more recent times is economically competitive with fermentation. So for instance, fermentation of sugarcane is easily cheaper in Brazil, but in America most industrial ethanol came from synthesis until corn subsidies were introduced in the 80s which made fermentation cheaper than synthesis.

The US has ample ethane now (it's abundant in much fracked gas) so I suspect this synthesized ethanol would be superior here without the corn subsidies.

A 50lb bag of cracked corn is about $12 at Tractor Supply. I've considered making my own moonshine just for the hell of it. Might actually get around to it one of these days.

Apparently modern US production ratios for ethyl vs isopropyl alcohols are roughly 100:1.

Expect they would have been the same during the war era, hence engineering torpedos to run on a more widely available fuel.

It’s currently that way because of ethanol in fuel correct? It seems unlikely it would have been that way during WW2?

Isopropyl is drinkable (and highly intoxicating). Just very unpleasant to drink and highly irritating to the mucosa.

If I recall correctly, a politician's wife back in the 80's was hospitalized for drinking isopropyl.

(Just looked it up on Wikipedia - I recall correctly)

https://www.washingtonpost.com/archive/lifestyle/1989/11/09/...

Kitty Dukakis

You can be hospitalized for drinking too much ethanol, or too much water. Are those not drinkable?

I'm an ER physician. I have worked in a poison control center. I take care of the people that drink IPA. I work on the Navajo Native American reservation, where this isn't terribly uncommon.

"When it comes to drinking rubbing alcohol, the digestive tract suffers the most, even when only swallowing a small amount. The body metabolizes these extremely high alcohol levels into acetone. If consumed to intoxication, the substance can lead to organ damage. Because it's a central nervous system depressant, side effects can include dizziness, headaches and inebriation. Because it's a gastrointestinal irritant, it can cause nausea, abdominal pain and vomiting blood. In addition, "due to having a higher molecular weight than ethanol, isopropanol, is more intoxicating than ethanol and can produce an altered sensorium, hypotension, hypothermia, and even cardiopulmonary collapse. Hypotension is associated with severe overdose and related to a mortality rate of nearly 45 percent," according to the National Center for Biotechnology Information (NCBI).

I am not sure I would call that "drinkable", unless you just mean it will physically go down your gullet.

Please see my response to a sibling commenter.

Nearly everything above is also true of ethanol.

Drinking too much water is also lethal.

I take care of plenty of patients that drink IPA. It is not uncommon in both people that think it will kill them and do it as a suicide attempt, as well as people that are desperate for a buzz but can't access ethanol (I work on the Navajo nation where ethanol is illegal and more difficult to obtain).

In general, these patients sober up and go home, just like patients that drink ethanol. Compared to ethanol, patients are much more intoxicated, take much longer to get sober, and are more likely to exhibit symptoms of gastritis or esophagitis. But there is nothing about caring for them that is categorically different than caring for a patient with a significant alcohol ingestion -- in both cases, it is dose dependent.

Fair point. At high enough levels, ethyl alcohol is also a pretty effective poison.

What was the source of the oxygen to maintain ethyl alcohol combustion in a sealed WWII torpedo?

Compressed air. https://en.wikipedia.org/wiki/Torpedo#Wet-heater

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