Levulinic acid is a versatile chemical precursor, whereby GVL may produced.
Most of the outlined descriptions for the reductions (to gamma-hydroxy-valeric acid) are under high pressure conditions and use gaseous hydrogen. One
paper describes a reduction with formic acid (which might be a byproduct of the levulinic acid production from various sugars) and a Ru/C-Catalyst -
is raney nickel usable with formic acid (i doubt it...)?
Or is another simple catalyst able to reduce it preferebly with the help of formic acid under mild conditions?
It's not electrochemically possible i think (reduction has been done on a lead electrode without success - was in one step too far to valeric acid
reduced).
Thanks in advance for any useful thought on this.Nicodem - 20-7-2011 at 12:23
You want useful thoughts, but don't bother giving the pertaining references? No input, no output.Ninja - 21-7-2011 at 00:43
You want useful thoughts, but don't bother giving the pertaining references? No input, no output.
You are right.
I don't have the full paper (here) for the ru/c-reduction. But i have another paper with related info:
Attachment: C1GC15047B.pdf (803kB) This file has been downloaded 1507 times
Here are references for ordinary reductions under rather harsh conditions.
So, what do you think? Are there any low pressure reductions of levulinic acid?
Dialkylketones are not easy to hydrogenate using simple catalysts or low pressures/temperatures.
You can try with sodium dithionite (UTFSE for references). It might be as simple as refluxing levulinic acid in an aq. solution of Na2S2O4 and Na2CO3.
If the carbonyl group gets reduced, acidification should give racemic gamma-valerolactone (though isolating it might be an annoying process).
Reduction of ketones with dithionite usually requires using DMF as a cosolvent with water, but unlike most ketones, sodium levulinate is soluble in
water.
Some metal dissolving reactions can also reduce ketones to alcohols, though rarely efficiently or cleanly. Perhaps zinc in acetic acid?497 - 19-1-2012 at 21:46
You could try cyclisizing it in to 5-methyl furanone and hydrogenating that. Ninja - 27-1-2014 at 09:05
Hi!
The reduction with sodium dithionite is possible but would alkoxides work too?
I would like to reduce it with sodium ethoxide if possible...
Thanks, for all the replies!Ozone - 27-1-2014 at 15:32
Going after Dumesic, eh? Perhaps toward the hydrolysis of cellulose to glucose and subsequent conversion to HMF?Random - 27-1-2014 at 16:11
What about aluminum isopropoxide it is used to reduce ketonesCrowfjord - 27-1-2014 at 16:47
Ninja: Alkoxides are certainly terrible reducing agents, at least toward such weak oxidizers as ketones. Perhaps you mean a dissolving metal
reduction, using sodium in ethanol? As said by Nicodem above, they can work, just not efficiently or cleanly.
Ozone: What the heck is Dumestic?Paddywhacker - 27-1-2014 at 20:11
[Edited on 28-1-2014 by Ozone]Crowfjord - 27-1-2014 at 21:58
Ah. Haha, my silly brain added a letter that wasn't there. No wonder my search turned up nothing useful. Thanks, Ozone, that's pretty interesting.
[Edited on 28-1-2014 by Crowfjord]Ozone - 27-1-2014 at 22:03
Check that link again, I got into the paper chase and posted a link to a different article.zed - 28-1-2014 at 19:52
NaBH4 should do the trick, but not cheaply. The Meerwin-Pondorf-Verley Reduction is a good idea and worth a try. It sometimes works very well.
Been a lot of noise about converting waste cellulose to levulinic acid, and using esters of that levulinic acid as diesel type fuel. Much noise,
little action. Folks would love to build and sell you a multimillion dollar pilot plant. Alas, it would appear such plants are not yet practical.
When I cruise the web looking for esters of levulinic acid, the product is quite expensive. Ninja - 9-12-2014 at 08:43
"Die elektrolytische Reduktion von Lävulinsäure und α-Dimethyllävulinsäure" by Tafel is a good paper about it. He uses Pb electrode in alkaline
medium to get the hydroxy-acid in 50-80% yield. Electrolysis in acidic medium produces valeric acid.
"Reduction of Aldehydes and Ketones by Sodium Dithionite" shows a reduction with dithionite with about ~50% yield ... to the hydroxy acid.CuReUS - 12-12-2014 at 01:33
Ninja: Alkoxides are certainly terrible reducing agents, at least toward such weak oxidizers as ketones. Perhaps you mean a dissolving metal
reduction, using sodium in ethanol?
i wonder what would happen if you replace ethanol with glycerol ?
but wont most of the Na or Li react with the COOH instead of the alcohol
and the alcohol must be adsorbed on the surface of the Na for the sodium to donate the electrons to the alcohol
since most of your metallic sodium is being eaten away by the acid,the yield will be reduced
also ,sodium hydride (NaH) gives better yield than sodium
the MPV reduction gives good yields,takes place in mild condition,is rapid and side reactions are negligible
aluminum isopropoxide can be made at home
the acetone formed can be distilled off to shift the equilibrium in the forward direction,if the acetone is not removed,the reverse reaction can take
place
in the oppenauer oxidation(the reverse of MPV ,oxidation of alcohols to aldehydes and ketones) ,using better hydrogen acceptors like p-benzoquinone
will allow you to oxidise primary alcohols to aldehydes
so i was thinking ,if hydroquinone is used for the MPV reduction ,can the yield be increased
aryl ketones have also been used instead of quinones to increase yield in OPP OX
so can benzyl alcohol be used in the reduction process ?
you would get benzaldehyde(which would furthur get oxidised to benzoic acid),but you can't distill it out as boiling point of benzaldehyde is 178 'C
while aluminum isopropoxide is 125 'C
NaBH4 can be used ,but wont some of it get wasted reacting with the COOH to release H2 ?
and on reducing levulinic acid using MPV reduction,the gamma hydroxy valeric acid will esterify to give gamma valerolactone
[Edited on 17-12-2014 by CuReUS]zed - 18-12-2014 at 16:03
Well, the MPV is easy enough to try. Take some levulinic acid, mix it with excess anhydrous isopropyl-alcohol, add catalyst, and distill. If
acetone comes over, the reduction is working.
Under some circumstances, yields are reported to be quantitative. Benzaldehyde+ excess Isopropyl Alcohol+ heat+pressure= Bingo!
CuReUS - 28-12-2014 at 23:22
actually,MPV cannot be done directly on this molecule,because acids kill the aluminum isopropoxide catalyst
you will have to first esterify the COOH ,then MPV can be done
you could also try using sodium sulphite(Na2SO3) instead of dithionite.
they sell sodium sulphite for reducing chlorine levels in pools http://en.wikipedia.org/wiki/Sodium_sulfite
[Edited on 29-12-2014 by CuReUS]Nicodem - 29-12-2014 at 06:25
