Sciencemadness Discussion Board

formic acid synths

Little_Ghost_again - 14-11-2014 at 10:10

Hi
I would like to make a small amount of formic acid by small I mean 100ml or less.
How do I hydrolise chloroform to make formic acid? And what other ways would make it.
Thanks for the help
LG

Chemosynthesis - 14-11-2014 at 11:11

Oxidation of methanol is probably the simplest OTC method.

Little_Ghost_again - 14-11-2014 at 13:12

Ok thanks. I will look into that. I want to compare with ant formic acid from my red and black ant farms

HgDinis25 - 14-11-2014 at 16:00

Actualy, the best OTC method to produce small quantities of formic acid is the Glycerin - Oxalic Acid method:
http://www.erowid.org/archive/rhodium/chemistry/formic.acid....

Amos - 14-11-2014 at 16:50

I will second the oxalic acid method. I have tried and made a couple mL even with horrible 5% oxalic acid cleaner. The glycerol is recycled, too, so even more convenient.

HgDinis25 - 14-11-2014 at 17:43

Quote: Originally posted by No Tears Only Dreams Now  
I will second the oxalic acid method. I have tried and made a couple mL even with horrible 5% oxalic acid cleaner. The glycerol is recycled, too, so even more convenient.


I've done that reaction a few times and in all of them I was left with a viscous blackish liquid, probably glycerine with side products from the various reactrions happening at the same time (AKA crap). I've never been able to recycle it.

Texium - 3-6-2015 at 17:23

I just finished making some formic acid using the glycerol and oxalic acid method. I started by refluxing a mixture of 28 mL of glycerol (it was all that I had, I need to buy more) and 16 g of oxalic acid at about 100°C until CO2 evolution ceased. Then I set it up for simple distillation and distilled the product, with the distillate coming over at around 100-110°C. My yield was 16 mL of crude formic acid, but I have not yet titrated it to determine the concentration, and might not anyway since it's a quite small amount and I don't really need to know. It has a terribly sharp and biting smell to it, intensely burning my eyes and nostrils if I do so little to disturb it as pouring some into another container.

Next time I make it (at the suggestion of plante1999 via Skype), I will neutralize the formic acid after the initial reflux step, and then distill everything in the solution with a BP of less than 100°C to remove the allyl alcohol impurity that is formed in the reaction. This will be followed by reacidifying the residual sodium formate solution and distilling the more pure formic acid.

Loptr - 4-6-2015 at 07:46

Quote: Originally posted by zts16  

Next time I make it (at the suggestion of plante1999 via Skype), I will neutralize the formic acid after the initial reflux step, and then distill everything in the solution with a BP of less than 100°C to remove the allyl alcohol impurity that is formed in the reaction. This will be followed by reacidifying the residual sodium formate solution and distilling the more pure formic acid.


I recall allyl alcohol being a lachrymator, so I can imagine the distillate being quite irritating! :)

Oscilllator - 4-6-2015 at 19:12

Quote: Originally posted by Loptr  
I recall allyl alcohol being a lachrymator, so I can imagine the distillate being quite irritating! :)

Methinks this contributed to zts16's burning of the eyes and nostrils.

Texium - 4-6-2015 at 19:16

Quote: Originally posted by Oscilllator  
Quote: Originally posted by Loptr  
I recall allyl alcohol being a lachrymator, so I can imagine the distillate being quite irritating! :)

Methinks this contributed to zts16's burning of the eyes and nostrils.
I think it must have, because I've worked with pure 78% formic acid at school before, and while that definitely had an irritating odor, it was nowhere near as bad as the stuff that I made yesterday. It caught me somewhat off guard, as I hadn't read previously that allyl alcohol was a lachrymator.