From a mass balance perspective, the ether only comes from the dehydration of the alcohol: none of the sulfuric acid ends up in the final product. The sulfuric acid has two purposes: The acidity is a catalyst for the reaction, and concentrated sulfuric acid is quite hydrophobic, so it will sequester the water from the dehydration to drive the reaction forward. Although, it sounds like oil of vitriol might have been rather dilute anyways, which would hurt it’s dehydrating ability. I bet the yield suffered.
A modern chemist could make the reaction happen faster than a couple months: they’d probably run the reaction at reflux (that is, boiling) to help it go faster, with a condenser to return the evaporated product to the flask. They might consider using a Dean-Stark apparatus to remove the water as they went, to drive the reaction forward.
Of course, if they wanted diethyl ether, they would buy some from Sigma-Aldrich. Wikipedia says most modern diethyl ether is a byproduct of turning ethylene into ethanol (going from ethanol to ether is more or less the same reaction as the alchemists would have used, although it would look very different)
The alchemist says:
“Oil of vitriolo. I start with vitriol romano, heated in a kiln. Just two drops in a glass of sweet wine. I warn you, the wine may have a burnt flavor. Good for stomach pains, foul breath, poor eyesight, aging and… melancholia.”
It also looks cloudy and green, though that could be the green tinted bottle initially poured from.
“The Jewish Alchemists: A History and Source Book” by Raphael Patai claims that vitriol romano is Ferrous Sulphate (FeSO4, a blue green solid). This is still used today to treat iron deficiency. According to a few references, depression is one symptom of anemia.
Heating it sufficiently, however, would turn it into Iron Oxide (Fe2O3). Since it looks green, I’ll assume he’s heating it enough to concentrate the liquid, rather than drive off the sulphur from the dry powder. Either way, it would be an iron supplement.
You phrased your question very well. Like you I became fascinated by what this was after watching the “Borgia’s” mini-series and found the same cross reference to Sulfuric Acid that you did, which, makes no sense. It had to have been something that perhaps was blended with other vegetable poisions, like nightshade, or some other common garden plant which when mixed with sulfuric acid released or enhanced the lethal poison in the plants, is my guess. That someone could take doses of this stuff and develop a tolerance for it clearly indicates it was not pure sulfuric acid.
I’m a Johnny-come-lately on this one, but I thought I’d add a fact to keep in mind regarding the historical reference to vitriol especially in Italian contexts. The word in Italian for vitriol is vitriolo, sometimes spelled in the past as vetriolo. Now the confusion enters because there was also an herb in use in Italian medicine called Vetriolo (sometimes vetriola or vetrinola: Parietaria officinalis). It was decocted like an herbal tea and drunk to heal kidney pain and bronchitis, both typical ailments of the elderly. Depending on how versed in archeo-phamacology the researcher for the Borgia series was, there may have been an erroneous translation.
The alchemical processes for isolating sulfuric acid/ oil of vitriol were certainly known in some circles in medieval Europe, however it was not part of standard licenced medicine in 1275 nor in the Borgias’ time. Around 1540 Paracelsian doctors and empirics were experimenting with it as a medicine, but the results were very controversial.
I have been researching antique cookbooks, 1800s mostly, and vitriol is a common, everyday ingredient. I get the sense that it was a household product. Old cookbooks have recipes for everything, not just food. There are references to different kinds of vitriol but usually oil of vitriol is the listed ingredient.
That’s all I know. I found this thread doing a google search for “what is vitriol”.
Okay, so this is a question that I’ve also been researching and so far this is what I’ve uncovered. I think what they are referring to in the Borgia series (the HBO version) is a substance that is "a distillation of sulfuric acid in ethanol (which is alcohol). Apparently you boil the ethanol (and here is where it gets a little confusing because I’ve read two different temeratures for distillation and I’m not sure which one it is) at 443K or 413K and a reaction occurs. I’m not sure if it forms ether or what it forms but it’s a volatile chemical that can cause intoxication. Further, from what I am reading even as I write this…okay so two different reactions occur, one at 413K, and one at 443K, but again, I’m still not sure what each reaction forms. It just says that you have to be careful not to use to much sulfuric acid because extraction of excess is hard to impossible…Oh wait, one reaction forms ethylene. Wow this topic seems to be rather secretive. Okay, let me do some citations here, and you can continue this thread of research on your own. But essentially, it’s an ether (there is more than one kind of ether apparently, and it comes down to the temperature that you boil the ethanol at that gives you a particular kind of ether. Some, I guess, are more concentrated/toxic than others. Dehydrated ethanol or dehydrated alcohol is a good search term to learn more.
Found out a little more and had to post it. Ethylene, is the main product of distilling ethanol and sulfuric acid. Other ethers can be produced at different temperatures, but ethylene was the main cause of the visions that the Oracle at Delphi had. Apparently Ethylene would fume up from cracks in the ground causing visions.
I can provide a slight answer as to the drinkablilty of oil of vitriol. When I was a teen (1960s) I tried my hand at trapping some muskrats and tanning the hides. I had an old outdoorsmen’s guide to such things. The tanning solution called for oil of vitriol to be diluted until it was as strong as strong vinegar when tasted. So I actually asked at a pharmacy about the oil of vitriol. Not only did they know it was sulfuric acid - they had some in stock! I guessed on the amount instead of tasting it and it didn’t work.
In admiring the titular gem in “The Adventure of the Blue Carbuncle” (1892), Sherlock Holmes remarks:
“‘It’s a bonny thing,’ said he. 'Just see how it glints and sparkles. Of course it is a nucleus and focus of crime. Every good stone is. They are the devil’s pet baits. In the larger and older jewels every facet may stand for a bloody deed. This stone is not yet twenty years old. It was found in the banks of the Amoy River in Southern China, and is remarkable in having every characteristic of the carbuncle, save that it is blue in shade, instead of ruby red. In spite of its youth, it has already a sinister history. There have been two murders, a vitriol-throwing, a suicide, and several robberies brought about for the sake of this forty-grain weight of crystallized charcoal. Who would think that so pretty a toy would be a purveyor to the gallows and the prison?..”
As a Harvard Ph.D. organic chemist, I believe the Oil of Vitriol in Borgias refers to morphine sulfate. The threads talk about sulfuric acid and, indeed, all sulfates are made using sulfuric acid [oil of vitriol, named for it’s viscous oily properties]. The reaction of ethanol and sulfuric acid does form diethyl ether as many suggest. However, diethyl ether does not exhibit any addictive properties. Morphine sulfate, made by treating opium powder from poppies with sulfuric acid, was know in Byzantine times. In my humble onion, mystery solved !
Elendil’s Heir, the vitriol-throwing Holmes refers to would be the more common meaning, sulfuric acid. One person is envious of another person’s looks, and so throws acid into that person’s face to disfigure them.