Sciencemadness Discussion Board
Not logged in [Login - Register]
Go To Bottom

Printable Version  
Author: Subject: Purification of denatured alcohol
kclo4
International Hazard
*****




Posts: 909
Registered: 11-12-2004
Location:
Member Is Offline


[*] posted on 16-6-2005 at 15:34
Purification of denatured alcohol


Denatured alcohol contains methanol and ethanol it is obviously hard to separate and I am not to sure if it is even possible but if you turned it in to NaOCH3 and NaOCH2CH3 it seems like there could be a way having both the salts with different melting points dose a any one have an idea how to separate the two

Melting point of NaOCH2CH3 = 260 C
I cant seems to find the other ones meting point




View user's profile Visit user's homepage View All Posts By User
12AX7
Post Harlot
*****




Posts: 4798
Registered: 8-3-2005
Location: soldering
Member Is Offline

Mood: informative

[*] posted on 16-6-2005 at 15:48


Then instead of an azotrope you have an eutectic. If they form either, that is.

Tim




Chemistry section: http://webpages.charter.net/dawill/tmoranwms/Chemistry.html

"I could take measurements, but why bother? Science just slows down chemistry!" - Myself
View user's profile Visit user's homepage View All Posts By User This user has MSN Messenger
Marvin
International Hazard
*****




Posts: 769
Registered: 13-10-2002
Member Is Offline


[*] posted on 17-6-2005 at 01:59


Methanol and Ethanol do not form an azeotrope but the composition of the vapour is close to the composition of the liquid so a very good reflux column is needed for any seperation.

The question is really, not how do I seperate, but how well can I seperate. What ever you do there will be some methanol in your ethanol and vice versa. I would suggest it isnt practical to make drinkable ethanol this way. If you need the methanol reduced for general chemistry this is probably feasable.

The only relavent data I was able to find is here,

http://users.chartertn.net/lpartin/software.html
View user's profile View All Posts By User
Hellhound
Harmless
*




Posts: 12
Registered: 18-6-2005
Location: Ukraine
Member Is Offline

Mood: hard

[*] posted on 19-6-2005 at 11:13


Pirydine and its bases are also often added to EtOH to make it undrinkable.
They gave alcohol bitter taste and cold be revealed with litmus paper. Pirydine boiling point is 115 'C and it can't be removed from alcohol either by distilling or freezing. Maybe an addition of some mineral acid would cause it to turn to pirydinium salts(though i don't know about solubility of these salts).
On the other hand ,pirydine can easily coordinate with any metal ions(e.g. Ag , Al , Co & Cu chlorides) giving insoluble complexes.
View user's profile View All Posts By User
The_Davster
A pnictogen
*******




Posts: 2805
Registered: 18-11-2003
Member Is Offline


[*] posted on 19-6-2005 at 11:34


I have some 95% EtOH that is denatured with camphor, diethyl benzy benzoate and diethyl phthalate. It is a brand of rubbing alcohol.



View user's profile View All Posts By User
FriendlyFinger
Hazard to Self
**




Posts: 64
Registered: 14-3-2005
Member Is Offline


[*] posted on 19-6-2005 at 16:01


The Denatured alcohol I use has 95% ETOH, 4.25% H2O 0.25%; MIBK, Denatonium Benzoate and Fluoroscein.

I'm told you remove the MIBK using NaOH and distilling. How exactly do you do that, and what about the rest of the junk?

Thanks,
regards FF
View user's profile View All Posts By User
Hellhound
Harmless
*




Posts: 12
Registered: 18-6-2005
Location: Ukraine
Member Is Offline

Mood: hard

[*] posted on 19-6-2005 at 17:12


MIBK can react with oxidizing agents, you may try to treat your alcohol with KMnO4 and then decantate cleared liquid. (Through this reaction various carbon acids may appear and probably you have to neutralize them). In some cases i think this method would be more convenient.
Fluoresceine,as it's triphenylmetane dye, can be also easily oxidized,though intermediate products, such as quinones may appear.
Camphor oxidizes easily with KMnO4 or other reactants to CO ,CO2 and H2O.
I don't know about denatonium benzoate. Judging by formula ,it's not so easy to oxidize this.
View user's profile View All Posts By User
sparkgap
International Hazard
*****




Posts: 1191
Registered: 16-1-2005
Location: not where you think
Member Is Offline

Mood: equilibrated

[*] posted on 20-6-2005 at 02:59


"...I don't know about denatonium benzoate. Judging by formula, it's not so easy to oxidize this."

I guess not. :) But maybe an alkaline extraction might be useful? It's still a quaternary ammonium compound after all.

(edit: heh, missed that, cyclonite4's right, it'll all become acetic acid if you keep ethanol and permanganate standing long enough.)

sparky (~_~)

[Edited on 20-6-2005 by sparkgap]




"What's UTFSE? I keep hearing about it, but I can't be arsed to search for the answer..."
View user's profile View All Posts By User
cyclonite4
National Hazard
****




Posts: 480
Registered: 16-11-2004
Location: is unknown
Member Is Offline

Mood: Amphoteric

[*] posted on 20-6-2005 at 03:41


Quote:
Originally posted by Hellhound
... try to treat your alcohol with KMnO4 ...


Somehow I see this oxidising the ethanol too (to ethanal and ethanoic acid)!




\"It is dangerous to be right, when your government is wrong.\" - Voltaire
View user's profile View All Posts By User This user has MSN Messenger
Hellhound
Harmless
*




Posts: 12
Registered: 18-6-2005
Location: Ukraine
Member Is Offline

Mood: hard

[*] posted on 20-6-2005 at 04:32


I agree about oxidizing EtOH too, but ,believe it or not, there's a long history of cleaning alcohol with KMnO4.
The hint is that a lot of admixtures will oxidize more quickly before a decent amount of EtOH would. (e.g. camphor, etc...)
View user's profile View All Posts By User
FriendlyFinger
Hazard to Self
**




Posts: 64
Registered: 14-3-2005
Member Is Offline


[*] posted on 20-6-2005 at 14:38


So what's the proceedure for removing MIBK? Do you just ad a bit of NaOH and distill? Simple as that?
View user's profile View All Posts By User
hAzzBEEn
Harmless
*




Posts: 14
Registered: 20-7-2005
Member Is Offline

Mood: FAIR

[*] posted on 22-7-2005 at 07:24
Methanol removal... moonshiners


I've read in distillation (moonshine) literature that methanol is removed from "mash" (mixture containing ethanol) by distillation and discarded. They are usually talking about < 1% methanol, but sometimes close to 1%, depending on the starting material for the fermentaion. They usually monitor/control the temperature in the boiling pot, and control the temperature in their uper and lower column by controlling the flow of cooling water to each.

With ethanol boiling at 78.5 F or ethanol/water azeotrope at 78.15 F and methanol (no azeotrope with water) boiling at 64.7 F, this seems feasible. One source did this by starting the boiling pot at 70 F and upper column at 62 F (for theirs). They carefully slow the flow of cooling water to the column until the temp at column top rises to 68 F and this releases the methanol vapor to the condensor. This is held until no more distillate is produced.

Could one use a vertical condensor with some type of packing as a column for temp control and a distilling adapter with thermometer on top of that to monitor the temperature? One could place a T in the cooling water line - run one of the outlets to the reflux condensor (column) and one to a shutoff valve and a return line to the cooling water tank or drain. The valve could be opened to slow the cooling water to the column and control the temperature. I have a T for my water hose with a valve for each outlet that could suffice (hard to control). If one column condensor wouldn't produce the temperature difference needed, maybe two would be required.

I know this is much more trouble than it's worth; this is pure curiosity. If I wanted ethanol, I'd just buy some Everclear or other PGA. It may be easier to control the temperature in 4 ft tall columns used for distilling 'shine. I'm sure the temp in the copper or stainless columns responds faster to the cooling water. It seems like if a moonshiner could do it, a mad scientist could do it, better. Enlighten me.


[Edited on 22-7-2005 by hAzzBEEn]




--hAzzBEEn--
View user's profile View All Posts By User
neutrino
International Hazard
*****




Posts: 1583
Registered: 20-8-2004
Location: USA
Member Is Offline

Mood: oscillating

[*] posted on 22-7-2005 at 07:30


Yes, a simple fractional distillation should do. A trick used by those too lazy to go to all this trouble is to just discard the first part of the distillate. By the law of partial pressures, most of the methanol is there.
View user's profile View All Posts By User
hAzzBEEn
Harmless
*




Posts: 14
Registered: 20-7-2005
Member Is Offline

Mood: FAIR

[*] posted on 22-7-2005 at 07:50


Yes, I have also read about this shortcut. I think the shortcut is used by most home distillers. I was quite interested in this some time ago.

According to the FDA:
Quote:
The Food and Drug Administration (FDA) advised ATF that 0.1 percent of methanol by volume in wine was a safe level. Any wine containing methanol in excess of this amount is deemed adulterated pursuant to the Federal Food, Drug and Cosmetic Act, 21 U.S.C. 34l(a)(2)(C) and 348

I found that info in the Methanol Info located at homedistiller.org. I thought it was ironic that on the same page, this was found:
Quote:
Methanol is a by-product of fermentation; more methanol is produced in fruit fermentation than in grains. Brewers do not remove the methanol in beer and wine because methanol is not especially toxic at low concentrations. You are looking at between 0.4%-1% methanol in wines and brandies and smaller amounts in beers. Distillers remove almost all the methanol in most cases. Ever notice how vodka produces clean hangovers and wines (particularly reds) give you very nasty hangovers? Methanol. That, and dehydration!




--hAzzBEEn--
View user's profile View All Posts By User
Fleaker
International Hazard
*****




Posts: 1100
Registered: 19-6-2005
Member Is Offline

Mood: nucleophilic

[*] posted on 2-8-2005 at 21:20


Interesting quote hazzbeen.

As Neutrino mentioned, most home distillers just toss the first couple ounces that come over.

I don't know if it's such a good idea to use a fractionalizing column with storebought denatured alcohol until it's been 'cleaned' up so to speak. The actual column is expensive, and rather large, mine is about 1.4m in height and has electric heating elements and probably the biggest thermometer I've ever seen.
View user's profile View All Posts By User

  Go To Top