Sciencemadness Discussion Board

Anything interesting to do with Lactic Acid?

Sulaiman - 9-8-2021 at 17:26

I bought a 90% lactic acid solution by mistake.
Is there any interesting chemistry?

karlos³ - 9-8-2021 at 17:45

You can make N-alkylalanines from it, by tosylation/halogenation followed by substitution with some primary amine, like methylamine.

N-methylalanine can for example react with (substituted) benzaldehydes to produce ephedrines in a single step, often in low yields, but it works.
Tried that with piperonal three times :)

The halogenated lactic acid, 2-halopropionic acid, could also be esterified and then reacts with benzaldehydes under sodium alkoxide catalysis to form phenylpropanones, via darzens.

You could oxidise it to pyruvic acid also.

But I actually don't remember anything else it would be useful for right now

Keras - 9-8-2021 at 22:34

Maybe you can use it at some point for enantiomeric resolution? Provided you have pure R or L-lactic acid, and not the racemic mixture.

Otherwise, make bio-plastic by auto-esterification.

unionised - 9-8-2021 at 23:44

Kettle descaling.

Lion850 - 10-8-2021 at 01:22

Does it make colourful salts with copper / nickel / cobalt / chromium / iron ?

draculic acid69 - 10-8-2021 at 03:33

I2/red phosphorus reduction to propionic acid

BauArf56 - 10-8-2021 at 03:41

ethyl lactate, as a sweet smelling solvent.

draculic acid69 - 10-8-2021 at 03:53

Quote: Originally posted by Lion850  
Does it make colourful salts with copper / nickel / cobalt / chromium / iron ?


Yes, at least with the copper. I googled copper lactate and seen some pictures of green/ blue solids and a link to woelens site.

Thanks for the suggestions

Sulaiman - 10-8-2021 at 04:46

None of the above excite me at the moment so I'll just store it until required

ShotBored - 10-8-2021 at 04:49

I've been getting into mushroom hunting lately and there is a super interesting variety where I'm at called a "Candy Cap" which has a very interesting aromatic molecule quabalactone III, which hydrolyzes into "sotolon" (3-Hydroxy-4,5-dimethylfuran-2(5H)-one) upon drying. This is what gives the candy cap a sweet aroma. Sotolon is also responsible for the aroma of maple syrup. It is also found commonly as an aromatic in wine. I would think that messing around with any of the aromatic lactone derivatives could be quite fun and have some interesting aromatic uses! I can't find a synthesis pathway for lactose to sotolon...my organic chemistry has been quite lacking the past few years anyways

Also if you dehydrate lactic acid into lactide, you can then polymerize it to form polylactide which is similar to polystyrene but is apparently biodegradable. But personally I think the aromatic lactones are more interesting

DraconicAcid - 10-8-2021 at 06:45

Quote: Originally posted by draculic acid69  
Quote: Originally posted by Lion850  
Does it make colourful salts with copper / nickel / cobalt / chromium / iron ?


Yes, at least with the copper. I googled copper lactate and seen some pictures of green/ blue solids and a link to woelens site.


I've made some quite nice crystals of copper lactate, *however*, it seems to form different hydrates and complexes under different conditions.

MarkoMiletic - 10-8-2021 at 07:06

Try dissolving some teeth in it. If you don't have spare personal teeth, than of someone else or animals.
Because naturopaths claim that lactic acid produced by bacteria is not destroying teeth, and they tried keeping them in acid for months and not affected. While modern science claims opposite, that we have to brush teeth.
I have not brushed teeth or visited dentist already for 15 years, and rate of tooth decay is same as of those around me who visit dentist at least yearly. I now only have 6 decayed teeth, 2 completely eaten away to the root, and 4 only partially, mostly those at the end of jaw, last ones, as predicted by naturopaths. I only feel toothache when exposed to high levels of stress, anxiety, summer heat...

DraconicAcid - 10-8-2021 at 07:09

Try dissolving a naturopath in it.

MarkoMiletic - 10-8-2021 at 07:19

Maybe I will, but after you convince me that tooth can be dissolved.
Don't believe in scientific studies which I only see as letters on paper.
Video of experiment would sound more convincing, but still not 100% as many videos and movies are simply fake.

Twospoons - 10-8-2021 at 17:09

Did it ever occur to you that you are simply lucky enough to have strong teeth? And that if you had brushed them regularly you'd have no decay whatsoever?

karlos³ - 11-8-2021 at 13:14

Quote: Originally posted by ShotBored  
I've been getting into mushroom hunting lately and there is a super interesting variety where I'm at called a "Candy Cap" which has a very interesting aromatic molecule quabalactone III, which hydrolyzes into "sotolon" (3-Hydroxy-4,5-dimethylfuran-2(5H)-one) upon drying. This is what gives the candy cap a sweet aroma. Sotolon is also responsible for the aroma of maple syrup. It is also found commonly as an aromatic in wine. I would think that messing around with any of the aromatic lactone derivatives could be quite fun and have some interesting aromatic uses! I can't find a synthesis pathway for lactose to sotolon...my organic chemistry has been quite lacking the past few years anyways

Also if you dehydrate lactic acid into lactide, you can then polymerize it to form polylactide which is similar to polystyrene but is apparently biodegradable. But personally I think the aromatic lactones are more interesting

You know thats strange that the quabalactone III hydrolyses under drying to sotolone, well, somewhat :P
Not so much anymore, if you consider the 91% of water in a mushroom, which are set free then.

Could I ask you where you're located, just in general, and what kind of woods you find them in?
I love mushroom hunting too, and this year was so wet, I think it will be a very mushy autumn :)

I wish I would have been there near that chemical plant where they accidentally released 4l of sotolone :D
(summer 2013 in Neuss)
The best with sotolone is, that higher quantities will smell like Maggiwürze and not overly disgustingly sweet or such! :)


Sorry for the OT!


E: no, its not OT!
If you oxidise the lactic acid to pyruvic acid, you can react that with glycine, and the resulting cyclic amine would undergo a sandmeyer to give sotolone, I guess.
See the attached document.

[Edited on 11-8-2021 by karlos³]

Attachment: guerra2011.pdf (908kB)
This file has been downloaded 243 times


HydrogenSulphate - 11-8-2021 at 13:51

You could make some colorful transition metal lactate salts......
vanadium, chromium, manganese, iron, nickel, cobalt.
See how the colors of the lactate salts compare to transition metal salts derived from other carboxylic acids like formic (formate), acetic (acetate), propanoic (propanoate), ascorbic (ascorbate), sorbic (sorbate), tartaric (tartrate), citric (citrate), oxalic (oxalate), and so on.

DraconicAcid - 11-8-2021 at 14:29

Quote: Originally posted by HydrogenSulphate  
You could make some colorful transition metal lactate salts......
vanadium, chromium, manganese, iron, nickel, cobalt.
See how the colors of the lactate salts compare to transition metal salts derived from other carboxylic acids like formic (formate), acetic (acetate), propanoic (propanoate), ascorbic (ascorbate), sorbic (sorbate), tartaric (tartrate), citric (citrate), oxalic (oxalate), and so on.


The trouble with that is the lactate ion may or may not chelate to the transition metal, depending on the temperature, pH (the hydroxyl can be deprotonated at high pH when coordinated to a metal ion) and which ion is in excess, meaning you almost never know exactly what you're going to get.

[Edited on 11-8-2021 by DraconicAcid]

draculic acid69 - 18-8-2021 at 03:50

Quote: Originally posted by MarkoMiletic  
Try dissolving some teeth in it. If you don't have spare personal teeth, than of someone else or animals.
Because naturopaths claim that lactic acid produced by bacteria is not destroying teeth, and they tried keeping them in acid for months and not affected. While modern science claims opposite, that we have to brush teeth.
I have not brushed teeth or visited dentist already for 15 years, and rate of tooth decay is same as of those around me who visit dentist at least yearly. I now only have 6 decayed teeth, 2 completely eaten away to the root, and 4 only partially, mostly those at the end of jaw, last ones, as predicted by naturopaths. I only feel toothache when exposed to high levels of stress, anxiety, summer heat...


Everything U said above about your mouth is a reason to brush your teeth.
Also I question what kind of ppl your around if they see dentists regularly
& brush there teeth and still end up with a rate of decay
equal to you.

unionised - 18-8-2021 at 10:26

A while ago I was wondering how to stick perlite together to make a refractory.
I figured that sodium silicate was an option and I found that you can buy a solution in the DIY store as concrete water-proofer/ dust-proofer.

And I also figured that it would be possible to add an acid and precipitate silica gel- which would do a fine job of gluing the perlite.
But, of course, the gel production is very fast (unless the solution is so dilute as to be useless as glue).

So I added ethyl acetate to the silicate solution.
That worked quite well- the ester hydrolysed to give acetic acid and that reacted so I go sodium acetate and silica gel.

But I couldn't get it to work as well as I would have liked because the ethyl acetate wasn't sufficiently soluble in the silicate solution.

But ethyl lactate is much more soluble in water
So, you could use lactic acid to make ethyl lactate and then see if you can make a homogeneous mixture with sodium silicate solution which should set to a gel.

That would be useful if you wanted to cast silica - though it would shrink a lot when you dry it and, if you don't wash the salts out of it, it would fall apart when it got hot





draculic acid69 - 21-8-2021 at 03:46

Quote: Originally posted by DraconicAcid  
Try dissolving a naturopath in it.


Interesting.

unionised - 21-8-2021 at 10:33

Naturopaths are notoriously hard to digest.
Or, at least, hard to stomach.

theAngryLittleBunny - 11-9-2021 at 22:57

Quote: Originally posted by karlos³  
You can make N-alkylalanines from it, by tosylation/halogenation followed by substitution with some primary amine, like methylamine.

N-methylalanine can for example react with (substituted) benzaldehydes to produce ephedrines in a single step, often in low yields, but it works.
Tried that with piperonal three times :)

The halogenated lactic acid, 2-halopropionic acid, could also be esterified and then reacts with benzaldehydes under sodium alkoxide catalysis to form phenylpropanones, via darzens.

You could oxidise it to pyruvic acid also.

But I actually don't remember anything else it would be useful for right now


I don't really think halogenating the hydroxy of lactic acid is realistically possible, since it is right next to a carboxyl group it behaves quite differently then a regular alcohol group. Also the lactic acid has 10% water, so anything that requires anhydrous conditions is out.

And I actually tried the oxidation to pyruvic acid with KMnO4, but it didn't seen to work and it started giving of bubbles which I assume was CO2. Maybe I would have had to cool it or dilute it more, or KMnO4 was just too strong, but yeah, lactic acid seems pretty useless lol.

Keras - 12-9-2021 at 02:05

I just realised that lactic acid is what is now sold over here (in Europe) in hardware shops under the moniker ‘substitute of hydrochloric acid’. So it's just available everywhere at about zero price point.


Tsjerk - 12-9-2021 at 02:23

You can also find it in webshop selling stuff for home brewing and making cosmetics.

theAngryLittleBunny - 12-9-2021 at 07:47

Quote: Originally posted by Tsjerk  
You can also find it in webshop selling stuff for home brewing and making cosmetics.


Yeah but can you do anything interesting with it, I couldn't really think of anything besides maybe polylactic acid. My first experiment with it was trying make solid sodium lactate from it. Sounds easy, but it seems impossible to remove all the water and get the solid salt, the closest I would get was a thick syrup and when I tried to dry it further it just charred. Even online I couldn't find solid sodium lactate to buy anywhere, kinda weird lol.