Paraformaldehyde to Formic Acid

[noj]

2HCHO + 2 NaOH + H2O2 ----> 2HCOONa + 2 H2O + H2

HCHO will be oxidized to formate / formic acid. The reaction will take 10 - 180 minutes depending on reaction temperature, pH, and H2O2 charge. With moderate temperatures (< 40 deg C) and a pH of 10 - 11, the H2O2 demand should be about 0.8 parts H2O2 per part HCHO.

It is possible to reduce the H2O2 demand by increasing the NaOH charge (to 2 - 3 g/L) and elevating the temperature (to 60 - 80 deg C) to affect aldol condensation. In this case, the H2O2 demand should be about 0.3 parts H2O2 per part HCHO.

It is also noted that hydrogen gas will be produced by the alkaline reaction. However, the risk can be easily managed if the flow is small and HCHO concentrations are low - i.e., for a 3,500 mg/L HCHO stream, the level of hydrogen that would be generated would be 117 mg/L. Nonetheless, the treatment should be done in an open vessel with reasonable headspace turnover - since the solubility of H2 in water is about 1.5 mg/L, virtually all the H2 will be evolved.


I am finding this very interesting, and would like to know if someone could use this reference to create a writeup in layman's terms. On hand is paraformaldehyde, 30% H2O2, and sodium hydroxide, but need amounts of each. Thanks for any input!

Source

(http://www.h2o2.com/applications/industrialwastewater/hcho.htm)
A theory is a tool - not a creed. -J. J. Thomson

[noj]

Okay after taking a couple tutorials on molarities, let me see if this looks alright:

60.052g paraformaldehyde
79.992g sodium hydroxide
34.014g hydrogen peroxide (what would this be in 30% solution?)

to yield:
136.012g sodium formate
36.03g water
2.016g hydrogen which will be evolved

Yeah?


I also need help in a safe method to produce the formic acid from sodium formate via sulfuric acid.

https://www.thevespiary.org/rhodium/Rhodium/chemistry/formic.acid.html

An aqueous solution of formic acid is obtained by distilling the sodium salt with dilute sulphuric acid: (what dilution?)

2 HCO2Na + H2SO4 = 2 HCO2H + Na2SO4

Anhydrous formic acid is obtained from the aqueous solution (70-77%) by the addition of butyl formate followed by distillation. The first fraction is an azeotrope of ester and water, and then the excess of ester is removed from the formic acid by fractionation.

Do not mix concentrated sulfuric acid with sodium formate or anhydrous formic acid.
The formic acid will be oxidized to the very toxic gas carbon monoxide by sulfuric acid!

[psychokitty]

I'm almost certain that oxone will oxidize both formaldehyde and methanol into formic acid.  Check the original oxone JOC article for further details.

[goiterjoe]

If this reaction is carried out in a slightly acidic medium, will a one to one ratio of hydrogen peroxide to paraformaldehyde result in a decent yield of formic acid, or will the reaction favor reducing the formic acid down to carbon dioxide?  I imagine that acetic acid would be preferrable for making the reaction medium acidic.  Does anyone have any details they would like to add to this?  I would really like to try this out sometime in the near future.
If Pacman had influenced us, we'd run around dark rooms eating pills and listen to repetitive music

[foxy2]

I think this will have the tendency to oxidise it all the way to CO2, but maybee not.
I hate my government, does this mean I'm a terrorist??

[UKBEE]

Hi

There are OTC(in UK) products containing FORMIC ACID so why bother making it, KILL-ROC is one(i think thats what its called) contains formic acid (not sure about strength)

Anyone know how to figure out the strength ?

Its available is a well known UK Hardware Store

UKBEE




Being good gets you stuff,Being stuff gets you good
Good stuff gets you being

[PrimoPyro]

Well in the US especially where Im from, its not OTC at all, so some of us need to know how to make it.

                                                    PrimoPyro
Vivent Longtemps la Ruche!

[UKBEE]

Well thats the least of your problems. safrole is controlled over here no easy sources :-(
I love the smell of Ketone in the morning.

[noj]

Would 800mL of 3% H2O2 have 34g of H2O2? And would that be enough excess water to allow 80g NaOH to be pH 10-11? This obviously would have to be an outside affair due to the H release.


Real men cook naked.

[PoohBear4Ever]

I'd guess more like 27-28g H2O2 (w/w), after trying to calculate mass by adding 100g extra for H2O2 density, then multiply by 3%...

Does density differ from adding two pure substances? (e.g. A=1g/mL B=2g/mL... A+B=1.5g/mL ?)

PB
concoct: 1) to prepare by combining raw materials; 2) to devise or fabricate

[noj]

I actually guessed at 800mL. Swim will use a cool 1L H2O2 then. Don't think an excess would be helpful.

If A=1 and B=2, then A+B=3 right?

This synth is for cleaning wastewater, so I believe an excess of water is okay. On that same thought, how would someone isolate 2HCOONa from water? Is evaporation the only way? Then an excess of water would only hinder.
Real men cook naked.

[noj]

Ah hell, sodium formate is used in photography. Guess it would be easier that way.
Real men cook naked.

[PoohBear4Ever]

If A=1 and B=2, then A+B=3 right?

What about the physical arrangement of the atoms within the solution (i.e. H2O2 to H2O molecular attractions)...

PB

*Guess some empircal evidence could help my hypothesis...

concoct: 1) to prepare by combining raw materials; 2) to devise or fabricate

[noj]

Mole fraction calculated from:

               WMw
Xh =   -----------------------
         Mh (100 – W) + WMw

Where:
Mw = molecular weight of water (18.016)
Mh = molecular weight of H2O2 (34.016)
W = weight % of H2O2
Xh = mole fraction of H2O2
 

Real men cook naked.

[Chromic]

>Well in the US especially where Im from, its not OTC
>at all, so some of us need to know how to make it.

Huh? If you don't have formic acid, use acetic acid... don't waste time on making sodium formate. (trust me on that one)

[PrimoPyro]

Chromic: I was merely responding to the mentality of, "Its available where Im at, therefore this discussion doesnt pertain to me, and since the world centers around me, its of no use to anyone."

I hate this idea that just because some people have access to a chemical, all of a sudden any synthesis of it is no longer appreciated. That is bullshit.

That was all I meant by my statement. In general, we Americans are the most guilty of this, but not this time.

                                                    PrimoPyro
Vivent Longtemps la Ruche!

[noj]

I agree. I only posted this ref for someone that may need it. That, and I like making things from things   .
Real men cook naked.

[Chromic]

Ok, looks like everyone is in agreement. The above synthesis is great, but there's other approaches to sodium formate. I'd choose ethanol and bleach as my #1 choice. The materials are more OTC.

[goiterjoe]

Well, SWIM did some experimentation and thought he'd mention the results here.  300ml 30% hydrogen peroxide was added to 140g paraformaldehyde(blue dye and all, big mistake.  it is extremely adviseable to at least wash some of the dye off with cold water washes.  It would be even better to wash it clean with cold water/methanol mixture.)  the flask was hooked up with a 600mm reflux condensor, even though it didn't need one.  the mixture was heated, and when it got to around 70C it started foaming up the dye and putting off heat of it's own.  this ran along for about 90 minutes, when it finally subsided.  There was about 40g of residual paraformaldehyde left in the flask which was filtered out, and then the reaction contents were distilled.  They should have been fractionally distilled, but swim didn't have the equipment to do so at the time.  After the flask foamed a bit more and settled down, ~250ml of liquid with a density of 1.08 was collected that smelled similar to vinegar, but not like vinegar, tested ph of 1 with litmus.  SWIM was wondering if there is a way to distill the 76% azeotrope of formic acid without a fractionating column, but doubts there is. 
If Pacman had influenced us, we'd run around dark rooms eating pills and listen to repetitive music