Sciencemadness Discussion Board

Glycerol to Butanol

tiny.ian - 8-6-2009 at 16:08

Just a to quell my curiosity. Maybe my understanding is wrong...

If one was to start at glycerol and "magically" add 2H, 1C and remove 2O wouldn't the resultant product be butanol? (I dont ACTUALLY mean magic is employed...)

Or by converting glycerol to any of the hydroxybutyric acids and... adding 2H, removing 2O from any of these hydroxybutyric acids...

(I feel like i've forgotten something- I feel like there's an extra H or OH somewhere... whatever... it's just madness at the moment)

Seems like this should be easy to do catalytically, enzymatically or through some other method... What else is there really?

Magpie - 8-6-2009 at 16:36

So you've given us a 3 carbon trihydroxy alcohol and want us to tell you how to turn it into a 4 carbon alcohol. You can't just pick out any old precursor and then "magically" make it into the compound that you want.

Try reading a book on organic chemistry, or better yet take a beginning course in organic chemistry. This assumes you already know the prerequisite basic chemistry. Even this does not seem apparent.

Sorry to be so hard on a 1st post, but this request is ludicrous.

Ozone - 8-6-2009 at 16:45

Not easy to do. It would not be economically feasible, despite the fact that your feed is cheaper-than-dirt. See here:

http://www.sciencemadness.org/talk/viewthread.php?tid=7036

for a few things that can be done with glycerol.

O3

JohnWW - 8-6-2009 at 16:49

An extra carbon can be added to aldehydes and most ketones by the cyanohydrin reaction with HCN, followed by acid hydrolysis. This produces either an alpha-hydroxy-carboxylic acid or (if H2SO4 is used) an alpha-unsaturated carboxylic acid with the extra carbon.

Ozone - 8-6-2009 at 17:07

Then you would like to proceed via cyanohydrin reaction with acrolein (from acid catalyzed dehydration of glycerol), hydrolysis, and subsequent reduction with LiAlH4?

I suppose it might work, but I don't think that would be safe (or responsible) to encourage this person to handle acrolein (war-gas quality lachrymator), HCN (deadly metabolic poison) or LiAlH4 (or other applicable pyrophoric metal hydride).

It would also be the most expensive n-BuOH on the planet.

I would encourage an anaerobic fermentation using Clostridium acetylbutylicum.

Cheers,

O3

ScienceSquirrel - 9-6-2009 at 03:35

Constructing this as a thought experiment as the chemistry would be very expensive in practice.
Glycerol could be dehydrated to form acrolein using potassium hydrogen sulphate, then 1,3 addition of methyl lithium in the presence of copper salts would yield butraldehyde.
Reduction with sodium borohydride would produce n-butanol.
Not practical chemistry but a good exercise in undergraduate arrow pushing and it has a certain 'elegance' in my eyes.

ScienceSquirrel - 9-6-2009 at 05:10

I can think of some other interesting transformations that could be carried out on glycerol to yield other products.
They are not very practical as synthetic procedures in most cases but are like chess problems or crosswords, paper exercises to be enjoyed in the evening in the garden or by the fireside.
Glycerol to Nylon 6 anyone? :D

[Edited on 9-6-2009 by ScienceSquirrel]

1281371269 - 9-6-2009 at 05:44

A point of order of sorts - shouldn't this be in organic?

tiny.ian - 9-6-2009 at 07:22

Quote: Originally posted by Magpie  
Sorry to be so hard on a 1st post, but this request is ludicrous.


I did say "Maybe my understanding is wrong"
And that it is to "quell my curiosity"

thanks.


Panache - 10-6-2009 at 04:08

Quote: Originally posted by tiny.ian  
Quote: Originally posted by Magpie  
Sorry to be so hard on a 1st post, but this request is ludicrous.


I did say "Maybe my understanding is wrong"
And that it is to "quell my curiosity"

thanks.




that being thus, it makes your question none the less......silly.

Qualifying, Magpie is probably the most forgiving of all contributers and he was curt. It is a very very silly question.

chemrox - 10-6-2009 at 15:51

Boris Karloff in the background singing along, "I was working in the lab, late one night ..."

Magpie - 10-6-2009 at 18:20

Although I thought this was a silly request, it is tantalizing to think of the money one could make if such a conversion was economically feasible. This is due to the potentially huge glut of glycerol that may someday exist as a byproduct of the production of biodiesel.

After all, chemists can make anything out of anything else, right? Even lead can be made into gold, I suppose, via nuclear transmutation.

not_important - 10-6-2009 at 22:56

Some of the most likely uses for glycerol are conversion to syngas ( in theory C3H8O3 => 3 CO + 4 H2), CO2 & H2 ( in theory C3H8O3 + 3 H2O => 3 CO2 + 7 H2), and a recently announced but not detailed hydrogenation of glycerol to methanol at fair low pressures and temperatures C3H8O3 + 2 H2 => 3 CH3OH. The last is significant because it in effect turns the waste glycerol into the needed amount of feedstock methanol.