What additives are in isopropyl alcohol (70%)

[Elite Engineer]

I distilled 70% isopropyl alcohol in order to make propene, later propeylene glycol. After the distillation, there was a leftover cloudy, green liquid in my florenece flask. Just curious, what is this green liquid, additives of the propanol? what are they, can they beused for anything?

 

~ee

[EdEarl]

My isopropyl alcohol 50% has no other ingredients listed; thus, I believe it should contain only distilled water.

[Elite Engineer]

My isopropyl alcohol 50% has no other ingredients listed; thus, I believe it should contain only distilled water.

I understand that some commercially sold alcohol used for medicinal use or such contains toxins purposely mixed to avoid being drank. I thought this may have been those additives

[hypervalent_iodine]

It almost certainly will contain stabilizers as well.

[Elite Engineer]

It almost certainly will contain stabilizers as well.

do you know specifically what these stabilizers are? Could they be of use or should I just discard the?

[hypervalent_iodine]

http://www.sigmaaldrich.com/catalog/product/sigma/i0398?lang=en&region=AU

 

According to that, the reagent grade stuff contains water, some carbonyls from oxidation and some non-descript acid or base.

 

And sorry, I neglected read the OP until just now. I was more talking about the stuff that you buy directly rather than the end product of your distillation. Not sure what it could be, though it doesn't sound like an additive to the isopropynol; especially if you've collected it in noticeable amounts. It's possibly a byproduct that's come about as a result of the distillation (depends on how you distilled it, however), though the green colour is odd. Otherwise, I guess it's some other impurity that's maybe reacted with the isopropanol. Is it water soluble at all?

[Elite Engineer]

http://www.sigmaaldrich.com/catalog/product/sigma/i0398?lang=en&region=AU

 

According to that, the reagent grade stuff contains water, some carbonyls from oxidation and some non-descript acid or base.

 

And sorry, I neglected read the OP until just now. I was more talking about the stuff that you buy directly rather than the end product of your distillation. Not sure what it could be, though it doesn't sound like an additive to the isopropynol; especially if you've collected it in noticeable amounts. It's possibly a byproduct that's come about as a result of the distillation (depends on how you distilled it, however), though the green colour is odd. Otherwise, I guess it's some other impurity that's maybe reacted with the isopropanol. Is it water soluble at all?

Thanks for the info! I'll try some tests and provide more info..I'm really curious about this.

[EdEarl]

I understand that some commercially sold alcohol used for medicinal use or such contains toxins purposely mixed to avoid being drank. I thought this may have been those additives

Isopropyl alcohol is toxic, it is ethyl alcohol that has methyl alcohol or another toxin added to be sold for medical purposes.

[Elite Engineer]

i ve done some testing on this murky, light green liquid i obtained from distilling isopropyl alcohol. It has a pH of about 7, it soluble in water and other polar solvents, insoluble in nonpolar solvents, does not react with any bases it comes in contact, and same with acids. When mixed with ethanol, the green, murky layer sinks to the bottom, and the ethanol rises to the top so it is somewhat more dense than ethanol. Any idea anyone? I i distilled it once with an alcohol burner, and distilled a different sample with boiling water and received the same results.

 

~ee

[John Cuthber]

it is ethyl alcohol that has methyl alcohol or another toxin added to be sold for medical purposes.

No it isn't.

That's denatured alcohol.

IPA is a different chemical.

[Sensei]

Elite Engineer, EdCarl, where did you get isopropyl that is not pure, so you have to distill it?!

 

In any electronic shop you can always get 99.9% pure C3H8O...

http://en.wikipedia.org/wiki/Isopropyl_alcohol

 

It's essential thing to run cloud chamber.

I have liters of it:

 

It costs 5$ for 1 L.

Edited January 13, 2014 by Sensei

[Elite Engineer]

Elite Engineer, EdCarl, where did you get isopropyl that is not pure, so you have to distill it?!

 

In any electronic shop you can always get 99.9% pure C3H8O...

http://en.wikipedia.org/wiki/Isopropyl_alcohol

 

It's essential thing to run cloud chamber.

I have liters of it:

 

It costs 5$ for 1 L.

I didn't know this, otherwise I would have bought that instead. I thought there was only 70% sold commercially, and 99.99% only for industrial use. I'll be sure to get that next time. In relation to the OP...any last thoughts on what the green murky solution is? Just want to make sure I distilled this properly.

[Sensei]

I didn't know this, otherwise I would have bought that instead. I thought there was only 70% sold commercially, and 99.99% only for industrial use. I'll be sure to get that next time. In relation to the OP...any last thoughts on what the green murky solution is? Just want to make sure I distilled this properly.

 

Distillation of pure methanol, ethanol, isopropyl, or with mixture with pure water should give you just initial alcohol.

 

They will be first flowing because they have lower boiling point than water (methanol first 65 C b.p, ethanol second 78 C b.p., isopropyl last with 83 C b.p.).

 

That's why we have to flush away the initial result of distillation of home made moon shine, because it's methanol.

 

We don't know what source of isopropyl you used. You should check out label to learn what it contains.

We don't know in how clean environment you were doing distillation...

Did you use glass or metal bulbs and pipes?

What metal(s)?

Take photo of setup, it'll be easier for you and us to tell..

Bought in chemical equipment shop?

These tend to be made of heat resistant glass, with small capacity, but chance to contaminate is minimized.

 

Bought in shop with alcohol distillers, etc stuff.. ?

These tend to be made of copper or special steel, and aimed to distillate just moon shine ethanol, not general purpose distill.

 

Or built by yourself?

[Elite Engineer]

Here's the distilling kit I used to distill the isopropyl alcohol:

 

 

 

 

 

 

 

 

 

 

 

-The flask on the left contains green, murky material that was separated from the propanol. The middle, smaller flask is the distilled propanol. I measured out 80 mL of non-distilled propanol. The bottle of isopropyl is on the far right, contains 70% propanol, and 30% water...you can't read it on the label but it does say that. It was purchased at Walgreens.

 

 

 

 

 

 

 

 

 

 

 

 

 

~EE

Edited January 15, 2014 by Elite Engineer

[Sensei]

I found higher resolution label

http://www.groceries-express.com/WebPages/3680091718%20Top%20Care.html

So it appears to be pharmacy product.

 

I would buy IPA in electronic shop and try distilling it to see whether it's giving the same result as the one that you already used.

Verify products from various sources and compare whether result is always the same.

 

Did you use ceramic/glass balls/pieces inside of bulb during distillation?

 

Did you make sure that you're not exceeding 83 C temperature too much?

Edited January 15, 2014 by Sensei

[John Cuthber]

 

Distillation of pure methanol, ethanol, isopropyl, or with mixture with pure water should give you just initial alcohol.

 

They will be first flowing because they have lower boiling point than water (methanol first 65 C b.p, ethanol second 78 C b.p., isopropyl last with 83 C b.p.).

 

No it won't.

Read up on azeotropes.

[Knumbnuts]

If I see it correctly you have rubber stoppers connecting the bits of glassware?

It may be that the isopropanol at reflux temperature has dissolved something out of the rubber, perhaps a radical inhibitor. You don't need much substance to get some colour.

[Elite Engineer]

If I see it correctly you have rubber stoppers connecting the bits of glassware?

It may be that the isopropanol at reflux temperature has dissolved something out of the rubber, perhaps a radical inhibitor. You don't need much substance to get some colour.

Correct, I do use rubber stoppers, however wouldn't the manufacturer make the rubber so it wouldn't react with any substances being distilled?..I really don't know. Also, the distilled propanol is clear and appears to be unaffected by any potential radical inhibitor.

[hypervalent_iodine]

I'm not sure how other labs do it, but all of the distillations I've ever done have used greased ground glass joints, no rubber seals required. I suspect Knumbnuts is right and it's the rubber that's giving you the green stuff.

[Knumbnuts]

Labs do not use rubber stoppers these days, it's all ground glass joints. In the early days leeching of additives form the rubber by solvents etc was a problem.

How do you know that nothing distilled with the isopropanol?

Any additive will dissolve in the refluxing solvent and will not distill, as they are usually not volatile compounds. So if this is the problem they will concentrate in the distillation residue.

[John Cuthber]

Correct, I do use rubber stoppers, however wouldn't the manufacturer make the rubber so it wouldn't react with any substances being distilled?..I really don't know. Also, the distilled propanol is clear and appears to be unaffected by any potential radical inhibitor.

How would they know?

Also if, as is fairly reasonable, the stuff in the rubber bung isn't volatile, it won't end up in the distillate.

Incidentally, distilling 70% IPA won't get the pure material. You can't get more than 88% w/w that way

http://en.wikipedia.org/wiki/Azeotrope_(data)

[Elite Engineer]

Labs do not use rubber stoppers these days, it's all ground glass joints. In the early days leeching of additives form the rubber by solvents etc was a problem.

How do you know that nothing distilled with the isopropanol?

Any additive will dissolve in the refluxing solvent and will not distill, as they are usually not volatile compounds. So if this is the problem they will concentrate in the distillation residue.

so did I just waste my money on a two-bit distillation kit? BTW Knumbnuts, thank you for answering my question!

Edited January 18, 2014 by Elite Engineer

[Knumbnuts]

Apparatus with ground glass joints is certainly a bit more expensive that individual pieces held in place with rubber bungs. But the expense is worth it. Have a look on e-bay you may well find apparatus quite cheaply there. If you look after it, like everything else, it will last forever, unlike rubber, which perishes over time.

Anything that distills over in your "rubber apparatus" will be pure, unless it is an azeotrope, but even that will be pure! The whole point of distillation is purification so having stuff remain in the pot is ok. The trick is to know where to terminate the distillation.