Vinegar as a solute for oils?

[DaveE]

OK, I know it's a odd question. The backstory isn't really chemistry, it's training search dogs to find essential oils. It's a passion of mine so I'll try to stay on point here. A big dog organization says to remove the residual oil, you should clean it with vinegar. Having seen oil and vinegar salad dressing I think they're totally off base. I use isopropanol or ethanol wipes, but my favorite household chemical would be acetone, I suppose. As an aside, not having to clean up is the best and normal practice.

So, can acetic acid play a role in dissolving vegetable oils when added to water. Clearly it's not non-polar like paint thinner.

Can simple acids work like alcohols or surfactants with a polar end and a non-polar end to improve water as a solute?

Are there other ways vinegar is better than water in dissolving oils?

PS: This seems like a useful page, but I don't know enough chemistry to understand the tables.
https://en.wikipedia.org/wiki/Solvent#Solvent_classifications

 

[jim mcnamara]

Essential oil is kind of a 'dumping ground term' for a broad range of compounds like terpenoids, e.g., menthol (mint) is a monoterpenoid. If you are removing these completely do you have to worry about toxicity?

If not, benzene is a good solvent, so is methanol.
If it is a worry try ethanol.

But.

I think what you really want is to learn about the baking soda treatment with white vinegar rinse.
https://silverbobbin.com/how-to-get-essential-oil-out-of-clothes/

This is supposed to remove essential oil odors. No great knowledge on my part - in grad school we extracted various terpenoids from food grade materials for analysis. Our clothing smelled awful. We used white vineger rinse after a run through laundry detergent (Tide) plus some extra Tween 80 and baking soda.

Tween 80: https://en.wikipedia.org/wiki/Polysorbate_80
I think Amazon has it. It is tough on some fabrics IIRC.

 

[sysprog]

Vinegar is neither an oil solvent, nor an oil solute, so it can't help to clean up oils; however, detergents are soluble in both oil and water, which is why they can help to clean up oils.

 

[jim mcnamara]

@sysprog
The link above does work. People who work in the spice factories where they create products like mint extract do use something like what I mentioned above. You are correct. But it is the baking soda that solubilizes the terpenoids. Vinegar helps to remove unused baking soda. Vinegar is not doing much to dissolve essential oils. Hopefully they are gone.

 

[sysprog]

@jim mcnamara, our posts overlapped $-$ I think that the process of applying baking soda followed by vinegar and then rinsing neutralizes acids and so makes the oils less odiferous.

 

[DaveE]

If you are removing these completely do you have to worry about toxicity?

No. The quantities are extremely small. We use Birch, Clove, Anise, Cypress, Vetiver, Myrrh, Eucalyptus, etc. Detection dogs have very sensitive noses. A typical target is made like this: Take a pint sized jar and with a small eyedropper put 3-6 drops of oil (extract) in trying to distribute it evenly. Then cut the cotton ends off of a bunch of q-tips. Add about 30-50 q-tip ends into the jar mixing evenly. Let the jar sit for at least a few days. Then each hide is made by putting 2-6 q-tip ends into some small vented container (to keep the oils from contaminating the surface you put it on). This is really stinky to a dog.

So, I'm only concerned with cleaning up trace amounts to remove the smell. The dogs will never get to any liquid. However, the odor can't be masked, the molecules must be removed or altered, otherwise the dogs will still smell it. I suspect that people think vinegar works because it smells like vinegar to them when they do it. Plus anything will transfer some oil to your paper towel, even nothing.

Isopropyl or ethanol wipes do this well enough. In any case nobody will be using benzene, I don't even use the acetone I already have. I'm really just wanting to be sure that when I tell people that vinegar is stupid that I'm correct.

 

[rbelli1]

I'm really just wanting to be sure that when I tell people that vinegar is stupid that I'm correct.

Send them to the salad dressing store. It will open their eyes!

BoB

 

[DaveE]

Vinegar is neither an oil solvent, nor an oil solute

Oops! Yes I meant solvent, LOL.
Although it does raise the question, for two liquids, which is which. I guess the one with more molecules is the solvent?

 

[Rive]

I'm really just wanting to be sure that when I tell people that vinegar is stupid that I'm correct.

Maybe what you need is an experiment, then. Mix up vinegar and some oil in a small bottle, then wait for the oil to gather on top and block the vinegar below. So the smell will be from the oil, and by mixing it up again you can prove that the vinegar is still there, doing nothing.

 

[sysprog]

Oops! Yes I meant solvent, LOL.
Although it does raise the question, for two liquids, which is which. I guess the one with more molecules is the solvent?

My understanding is that the thing dissolved is the solute, and that in which it's dissolved in the solvent, and the result of the disossolution is the soution. So e.g. in a saline solution, salt is the solute, and water is the solvent.

In the case of vinegar, which is both a solvent and a solution, the solute would be the acid anhydride of acetic acid.

In the case of a detergent, the surfactant is the solute, and it can be dissolved in both lipids and water. A roughly cylindrical detergent surfactant molecule has a hydrophopic and a hydrophilic end, and the hyprophobic end is lipophilic. This creates a briding effect betwen the water surface and the lipid surface, making the oil and water miscible.

I think that a good detergent for the purpose you have outlined is sodium lauryl sulfate, provided that it's plain, and not adulterated with perfumes and dyes as shampoo typically is.

 

[Mike S.]

A guess: The pH controls what solvents some chemicals will dissolve in. For example, the classic alkaloid extraction done by coca and opium growers relies on the idea that alkaloids dissolve well in organic chemicals when in "free base" form, but will dissolve in water when they occur as the salt. The catch is that any chemicals I remember in these essential oils don't do that - they're not amines but esters and ethers and alcohols. Nonetheless ... there are a lot of chemicals in an essential oil, and I imagine those dogs can smell minor components. The vinegar might be used with aqueous solutions to wash away the +HNR3 type compounds, or with more hydrophobic solvents to wash away something like salicylic acid.