Sciencemadness Discussion Board

Chloroform -> Formic Acid

Chemistry Alchemist - 10-10-2011 at 22:50

I may or may not be planning on doing this reaction, im just considering what additional steps should be taken then doing this reaction AKA Heating, reflux, distillation... this is the steps and what i think would have to be done

The first step is reacting 74.44 grams of Bleach with 58.07 grams of Acetone, this will make 119.37 Grams of Chloroform with a few by products... im guessing you just mix them together and keep it cool to let the 2 layers separate... the Chloroform layer at the bottom and the Sodium Acetate and Hydroxide layer up the top

NaClO + C3H6O → CHCl3 + 2 NaOH + CH3COONa

The next step is Dissolving 39.99 grams of Sodium Hydroxide in Some Ethanol and adding it to the 119.37 grams of Chloroform, This will produce 68.00 grams of Sodium Formate and 58.44 grams of Sodium Chloride. How would you separate the Sodium Chloride from the Sodium Formate?
Also, would this reaction proceed on its own or would i have to heat or reflux it for it to proceed?

CHCl3 + 4NaOH → HCOONa + 3NaCl + 2H2O

The last step once the 68.00 grams of Sodium Formate is isolated, it is then reacted with 98 grams of Sulfuric Acid, This will produce 46.02 grams of Formic Acid along with 142.04 grams of Sodium Sulfate. Now my last question would be How would i separate the Formic Acid from the sodium Sulfate?

HCOONa + H2SO4 → CH2O2 + Na2SO4

Does this sound about right? Please do correct me if im wrong :) and if this thread belongs in Beginners and not here then feel free to move it :)

francis - 10-10-2011 at 23:51

I would think you would need a phase transfer catalyst, to get the hydroxide ions to react with the chloroform, wouldn't it take too long oherwise?

What is the mechanism for this reaction, how does it work?

Does the base deprotonate the chloroform to form the trichloromethyl anion?

Then what would be the next step?



[Edited on 11-10-2011 by francis]

Chemistry Alchemist - 11-10-2011 at 00:54

I wouldnt really mind if it took ages tbh haha, i wouldnt know if it needs a catalyst, i just took all the info of Wikipedia and joined it together to form one thread, it didnn mention about catalyst but then again wiki doesnt tell everything... im not a experienced chemist, im just a guy wanting to make things :)

Picric-A - 11-10-2011 at 01:48

Why not make chloroform from sodium hypochlorite + ethanol. This would give chloroform and sodium formate as a salt. The formate can be protonated to give formic acid.

The chloroform can then be hydrolysed with NaOH and tetrabutylammonium bromide to give sodium formate and sodium chlroide. This formate can be liekwise pronated to give formic acid.


Chemistry Alchemist - 11-10-2011 at 02:13

So doing it with ethanol would make Formic Acid in 2 parts rather then 3 as i said above? Is Sodium Sulfate soluble in formic Acid?

Chemistry Alchemist - 11-10-2011 at 02:37

NaClO + C2H6O = CHCl3 + HCOONa

I know this equation is unbalanced how what is the missing link in the reaction?

bbartlog - 11-10-2011 at 02:41

Quote: Originally posted by Chemistry Alchemist  

Does this sound about right? Please do correct me if im wrong :)


Stoichiometry is wrong. First of all, you need three moles of NaOCl per mole of acetone. Second of all, since bleach is normally sold in aqueous solution you will need to account for that.
Also there is no point in specifying all your weights to the hundredth of a gram.
You will find if you do this with commercial bleach that the chloroform does not so much form a layer as it does a blob, i.e. you may be disappointed at how little chloroform you get. I notice that you assume 100% yields; my yields in doing this run about 50%. I'm sure that can be improved on but if you are planning on doing this for the first time I would not suggest assuming higher.
Anyway, there are threads on this part already.
The hydrolysis should proceed slowly even at room temperature, so heating would be needed just to make things happen more quickly. I would expect that you can separate the formate and chloride based on the fact that the former is somewhat soluble in alcohols while the latter isn't really, but there may be better ways.
Also, if you just want formic acid, you might look into acid decomposition of cane sugar. Would work out cheaper, I'm pretty sure.
Quote:
Why not make chloroform from sodium hypochlorite + ethanol.


This doesn't proceed nearly as easily as the acetone reaction.

Chemistry Alchemist - 11-10-2011 at 02:49

I wasnt assuming 100% yeilds i was just stating the moles of each chemical... could you evaporate the bleach to form a powder and then use that instead?

So for the Sodium Hypochlorite and ethanol, what do you mean by it doesn't proceed nearly as easily as the acetone reaction? is it much slower or are there more steps involved?

Retard-3000 - 11-10-2011 at 02:50

You'd be better of reacting the sodium chloride/sodium formate solution with HCl so you get formic acid and sodium chloride, then just distill of the formic acid.

Chemistry Alchemist - 11-10-2011 at 02:58

Could i just evaporate the solution of Formic acid/Sodium Chloride/Water? and let the Sodium Chloride crystallize out by its own

francis - 11-10-2011 at 03:01

Quote: Originally posted by Chemistry Alchemist  
So doing it with ethanol would make Formic Acid in 2 parts rather then 3 as i said above? Is Sodium Sulfate soluble in formic Acid?


I think there is no benefit to using ethanol, because why add the extra steps of trying to oxidise ethanol to a ketone?

The first reaction OP mentioned presumably produces CHCl3 by the haloform reaction.

I just wonder about the second part. There's some mention of it here:

http://www.archive.org/stream/identificationof00neavrich/ide...

Also here:
http://www.books-about-california.com/Pages/Experimental_Org...

Is the idea to have (-)OH ions act as nucleophiles, substituting for the chloride ions, to form orthoformic acid, decomposing to formic acid?

In this case, since chloroform would be the solvent, how do you get the hydroxide ions to react with the chloform, since chloroform is nonpolar?

Also, how should the hydroxide preferentially act as a nucleophile, rather than a base, in the second instance deprotonating the chloroform?

To the OP:
you should try and work out moles and molarity, it will make things easier than trying to calculate reagents in grams, because some of your reagents are liquids.

These equations you've written are useful for determining stochiometry, but only when you treat the species as moles of this, or that. This will help you work out the limiting reagent, and the theoretical yield.


[Edited on 11-10-2011 by francis]

bbartlog - 11-10-2011 at 06:02

Quote: Originally posted by Chemistry Alchemist  
I wasnt assuming 100% yeilds i was just stating the moles of each chemical... could you evaporate the bleach to form a powder and then use that instead?

So for the Sodium Hypochlorite and ethanol, what do you mean by it doesn't proceed nearly as easily as the acetone reaction? is it much slower or are there more steps involved?


You can't easily obtain solid hypochlorite by evaporation. The bleach tends to disproportionate. Also, you probably wouldn't want to. Even with 6% bleach the reaction is fairly exothermic; with 10% bleach you need to start with ice cold reagents to avoid boiling off the chloroform as it is formed. If you did have solid hypochlorite you would need to contain and condense the hot vapors as they formed, and probably risk an acetone fire.
So far as the ethanol reaction is concerned, I'm speaking mainly from personal experience. Ethanol plus bleach does not react much at room temperature nor up to about 50C, and doesn't smell at all of chloroform. Maybe there is a way to do it, or I just didn't give it long enough.
Quote:
You'd be better of reacting the sodium chloride/sodium formate solution with HCl so you get formic acid and sodium chloride, then just distill of the formic acid.


It would likely be better to use a different acid. Unless you're good at titration, you won't know exactly how much HCl to use to exactly neutralize the sodium formate. If you undershoot, you sacrifice yield; overshoot and you end up with excess HCl, which is not easily separated from the formic acid, at least by distillation. If you use sulfuric acid you can just use a moderate excess and not worry about it distilling over with the formic acid.

Chemistry Alchemist - 11-10-2011 at 07:20

so ur saying with the ethanol and bleach that it reacts extremely slowly at room temp? so say i left it for a week or a few weeks, do you think ill get a reaction? or even then it may not react much?

Plus using a more concentrated acid, you will have much less water in the formic acid, you can get 98% Sulfuric Acid but you cant get 98% Hydrochloric acid, only 32% i think

ScienceSquirrel - 11-10-2011 at 08:30

The reaction with ethanol involves initial oxidation to acetaldehyde (ethanal ) this then forms chloral ( trichloroacetaldehyde ) which cleaves to form chloroform and formic acid.
Other side reactions eg oxidation to acetic acid take place that consumes the reagents and lowers yields.
Most inorganic reactions are A + B ---> B + C and there are no side products and yields are quantitative, losses are due to recrystallisation and mechanical means.
Organic reactions are more like A + B ----> B + C + glop.
Often there can be more glop than product! :(

Picric-A - 11-10-2011 at 08:48

DO NOT use conc. sulphuric acid (>50%) to protonate the formate! This will only evolve odourless, toxic carbon monoxide and depending on the scale will only ever result in injury, or worse still death.

Stick with hydrogen halides or phosphoric acid.

Chemistry Alchemist - 11-10-2011 at 09:00

85% phosphoric acid then?

ThatchemistKid - 11-10-2011 at 09:10

The reaction between chloroform and NaOH Intially forms the trichloromethyl anion but that quickly collapses into the dichlorocarbene I am not so sure you can get sodium formate from that.

bbartlog - 11-10-2011 at 12:06

Quote: Originally posted by Picric-A  
DO NOT use conc. sulphuric acid (>50%) to protonate the formate! This will only evolve odourless, toxic carbon monoxide and depending on the scale will only ever result in injury, or worse still death.

Stick with hydrogen halides or phosphoric acid.


Who said anything about concentrated sulfuric acid? Yes, if you use enough high-test sulfuric that your final solution is >70% sulfuric acid, what you describe would be an issue. But that can be avoided by using 35% acid (sensible here anyway) or just not adding a vast excess.
Also, if you have phosphoric acid you can obtain formic acid just by heating it with cane sugar (but be warned that what is left in the vessel will be an awful mess).
Quote:
The reaction between chloroform and NaOH Intially forms the trichloromethyl anion but that quickly collapses into the dichlorocarbene I am not so sure you can get sodium formate from that.


Various 19th century works seem pretty confident in formate as the primary product (google books: hydrolysis chloroform formate). I seem to recall someone here has done the reaction, too.

Panache - 18-10-2011 at 02:14

use NaHSO4 or anhydrous citric acid to liberate the formic acid, if time is not an issue, grind the two together (ie the solid acid and the formate/NaCl mix) place into a distillation setup heat on steam bath, then leave the room for three days, voila!

edit, i have not done this, but it works for sodium acetate.

[Edited on 18-10-2011 by Panache]

Chemistry Alchemist - 18-10-2011 at 06:28

so all i have to do is get my hands on some sodium formate or another formate salt

ScienceSquirrel - 18-10-2011 at 06:36

Have a trip round the local hardware stores, etc. Some descalers are based on formic acid, usually about 40%.

Chemistry Alchemist - 18-10-2011 at 06:53

what exactly is a descaler?

watson.fawkes - 18-10-2011 at 06:56

Quote: Originally posted by Chemistry Alchemist  
what exactly is a descaler?
A descaler is a commercial chemical formulation to remove Ca- and Mg-based deposits from water high in their ions.

ScienceSquirrel - 18-10-2011 at 06:57

A descaler removes the 'fur' of insoluble salts that forms on the elements of kettles in hard water areas.

http://en.wikipedia.org/wiki/Anti-scaling_agent

Chemistry Alchemist - 18-10-2011 at 07:03

I just looked on heaps of msds's for descalers and most of the ingrediants is either Hydrochloric acid or Phosphoric acid, but then again, that could be different to whats in the shops

ScienceSquirrel - 18-10-2011 at 07:12

You may be unlucky living in Australia, there are quite a few in the UK

http://www.boots.com/en/Ataka-Bath-Stain-Remover-Kettle-Desc...

Chemistry Alchemist - 18-10-2011 at 07:20

Quote: Originally posted by ScienceSquirrel  
You may be unlucky living in Australia, there are quite a few in the UK

Yeah but i dont know what country msds's i was checking... i just googled descaler msds and clicked on heaps to check
Quote: Originally posted by ScienceSquirrel  

http://www.boots.com/en/Ataka-Bath-Stain-Remover-Kettle-Desc...


Thats really cheap :O about $3 Australian or a bit more, if it was here it would be about 10-20 dollars ><

Nicodem - 18-10-2011 at 07:23

Quote: Originally posted by Chemistry Alchemist  
The next step is Dissolving 39.99 grams of Sodium Hydroxide in Some Ethanol and adding it to the 119.37 grams of Chloroform, This will produce 68.00 grams of Sodium Formate and 58.44 grams of Sodium Chloride. How would you separate the Sodium Chloride from the Sodium Formate?
Also, would this reaction proceed on its own or would i have to heat or reflux it for it to proceed?

CHCl3 + 4NaOH → HCOONa + 3NaCl + 2H2O

What is the reference for the above?
I believe the expected main product under such conditions would be triethyl ortoformate. I really can't see how you could get sodium formate as the main product from such a reaction. The concentrated NaOH/EtOH solution is about 12% at which point there is enough ethanol for the ethoxide being in excess over the hydroxide. Some formate would certainly form, but I highly doubt it would be the main product, particularly since the third chlorine gets substituted by the solvent under diffusion control (SN1 substitution) so you don't even get the benefit of statistics.

PS: When writing equations of reactions proceeding in reactive solvents you need to include the solvent! Else, it is like a bird flying in vacuum.

Chemistry Alchemist - 18-10-2011 at 07:31

The reference is: http://en.wikipedia.org/wiki/Sodium_formate

Correct me if im wrong but if the solvent is in the equation, it wouldnt change and it would be the same on the right side as on the left... if u know what i mean...

Panache - 18-10-2011 at 07:31

formates for some reason are not available otc in australia, afaik, i have always found this odd, didn't reaslise you were australian earlier. i assume it's related to the poisons scheduling that is very harsh on methanol, and this was analogously transposed to formic acid and its salts. We haven't had a methanol poisioning of note here for some time (i'm in distilling), although last week a australian lass in Bali was evacuated from said island with severe methanol poisioning from a sugar cane punch. Her mother didn't fee like drinking so the daughter drank the entire jug, was 4.1 ethanol:methanol.
if anyone knows of an australia product based on a formate please post concerning it. Our descalers tend to be sulphamic acid or as mr chem ac stated HCl or Phosphoric. Oxalic acid acid is sold everywhere neat as well, for cleaning rust.

Nicodem - 18-10-2011 at 08:05

Quote: Originally posted by Chemistry Alchemist  
The reference is: http://en.wikipedia.org/wiki/Sodium_formate

Correct me if im wrong but if the solvent is in the equation, it wouldnt change and it would be the same on the right side as on the left... if u know what i mean...

There is no reference for that Wikipedia claim. It is just as relevant as me saying that pigs fly. They do when on an airplane, but it is not the same. Similarly, chloroform can give a formate salt, but in ethanol the reaction might or might not be preparatively reasonable (meaning that formate might not be the main reaction product!). Alternatively, it might also give formates if using ethanol only as a cosolvent for NaOH(aq), which is a possibility given that the equation is unrepresentative of the reaction. But all this is not the same, just like the pigs flying in an airplane are not the same species of pigs flying with wings. And that is why you need to include ethanol in the equation. An equation not listing all the species partaking the reaction is no reasonable chemical equation. When you write the left side of the reaction correctly, you at least have a chance to have the right side of the reaction also approximately correct.

Let me give you an exaggerated example, for the sake of illustration. Let's say you are preparing t-butyl acetate from acetyl chloride and t-butanol in an ice bath and using isopropanol as a solvent to dissolve the otherwise solid t-butanol. How would you write the equation of this reaction? (there is actually more than one level of complexity in this example!) Also: What are the products? Is the addition order important? Do the conditions matter? Can the stirring rate influence the reaction products? Does the reaction size matter? And so on... If you do this as a homework you might understand why equations like that Wiki's one are totally misleading.

Chemistry Alchemist - 18-10-2011 at 08:30

Quote: Originally posted by Nicodem  

Let me give you an exaggerated example, for the sake of illustration. Let's say you are preparing t-butyl acetate from acetyl chloride and t-butanol in an ice bath and using isopropanol as a solvent to dissolve the otherwise solid t-butanol. How would you write the equation of this reaction? (there is actually more than one level of complexity in this example!) Also: What are the products? Is the addition order important? Do the conditions matter? Can the stirring rate influence the reaction products? Does the reaction size matter? And so on... If you do this as a homework you might understand why equations like that Wiki's one are totally misleading.


Did u want me to try work it out?


[Edited on 18-10-2011 by Chemistry Alchemist]

Aqua_Fortis_100% - 18-10-2011 at 22:04

Why not make it just from oxalic acid and glycerol? Much simpler..

Oxalic acid is OTC in most places and even if dont, you can make it from sawdust and NaOH or from sugar/HNO3..

http://www.homechemistry.org/view/Preparation_of_formic_acid

http://web.archive.org/web/20080424022524/http://www.frogfot...

Chemistry Alchemist - 19-10-2011 at 00:51

How can it be made from Sawdust and NaOH? i have alot of both...

Aqua_Fortis_100% - 19-10-2011 at 01:17

Quote: Originally posted by Chemistry Alchemist  
How can it be made from Sawdust and NaOH? i have alot of both...


Very messy, dangerous and gives a product that needs somewhat heavy purification.. If you still want, good luck! Tried myself on minor scale and the yield wasnt great..

Look the papers attached by not_important in the end of first page of this thread:

http://www.sciencemadness.org/talk/viewthread.php?tid=8912

If you want a elegant route.. See this:

http://www.sciencemadness.org/talk/viewthread.php?tid=12832


Chemistry Alchemist - 19-10-2011 at 01:32

ahh i see... yeah maybbe it is a bit hard to make.... i really do wanna get into organic chemistry but i dont have the right equipment and chemicals :(

bbartlog - 20-10-2011 at 17:13

For those curious about references that might or might not back up the claim in Wikipedia, I would suggest looking up Watts' Chemical Encyclopedia on Google Books. It gives further (even hoarier) references to works by Regnault and other early experimenters. But it does not look too promising, preparatively: apparently KOH, ethanol and chloroform will give you formic acid (and KCl, and gunk)... if heated to 100C for a week in a closed tube. Boiling alkali in aqueous solution with chloroform supposedly does nothing.

Foss_Jeane - 1-11-2011 at 14:27

The other possibility for getting formic acid is the electrolytic reduction of sodium bicarbonate in a partitioned cell over a Hg or Pb cathode. (It also works with sodium carbonate and even bubbling in CO2 will give some formic acid.) The method never got a lot of attention since, at that time, cyanides were easier to make than ammonia, and all the ammonia was derived from NaCN (bring it to red heat, pump in superheated steam and collect the ammonia. Sodium formate was the by-product and not exactly in short supply).

Other, more esoteric methods involved the use of glow discharges that likewise produced formic acid and several other interesting end products, though this is a good deal less easy to pull off. (Requires high voltages and vacuum techniques. Though it does explain why CO2 lasers are never sealed systems: you need to take 'em apart regularly to clean out the organic crud that accumulates.)

Electrolytic methods got a lot of attention during the first two decades of the 20th century, and the relevant texts were written by Bertram Blount and others. They fell out of interest, as newer industrial methods were developed as a result of WW I. They still work, and if you're not looking to make tons of the stuff, it's worth considering. A helluvalot less messy than trying to use some version of the haloform reaction if it's not chloroform you're after.

So far as reacting CHCl3 with hydroxides, that only works well if the "chloroform" is a side chain on a benzene ring, such as a,a,a trichlorotoluene.

bbartlog - 1-11-2011 at 17:09

Quote:
that only works well if the "chloroform" is a side chain on a benzene ring


Doesn't have to be a benzene ring. Chloretone/chlorobutanol is pretty readily hydrolyzed (apparently to hydroxy-tert-butyric-acid) by base... also I recall one of our members synthesizing hexachloropropene from unsym-heptachloropropane, again the CCl3 was attacked by Ca(OH)2. Seems like attaching just about any group of carbon atoms to the -CCl3 will destabilize it.

sodium formate from chloroform

reckless explosive - 5-4-2012 at 18:21

i have gained a broad collection of sodium salts being that it is one of my favorite elements all of which ive made myself except sodium formate and through several of the different posts of chloroform i saw that if you mix chloroform with sodium hydroxide it will form the formate and i have search on google and here but nothing on this specific synthesis shows up. so my question is could i take the dirty undistilled chloroform(as i dont have a distillation kit yet :( ) from the reaction of bleach and acetone and mix it with NaOH will i get sodium formate or will several salts form? also any interesting reactions with sodium formate would be helpful other than the obvious creation of formic acid.

chloroform

cal - 6-4-2012 at 07:28

Quote: Originally posted by Chemistry Alchemist  
I may or may not be planning on doing this reaction, im just considering what additional steps should be taken then doing this reaction AKA Heating, reflux, distillation... this is the steps and what i think would have to be done

The first step is reacting 74.44 grams of Bleach with 58.07 grams of Acetone, this will make 119.37 Grams of Chloroform with a few by products... im guessing you just mix them together and keep it cool to let the 2 layers separate... the Chloroform layer at the bottom and the Sodium Acetate and Hydroxide layer up the top

NaClO + C3H6O → CHCl3 + 2 NaOH + CH3COONa

The next step is Dissolving 39.99 grams of Sodium Hydroxide in Some Ethanol and adding it to the 119.37 grams of Chloroform, This will produce 68.00 grams of Sodium Formate and 58.44 grams of Sodium Chloride. How would you separate the Sodium Chloride from the Sodium Formate?
Also, would this reaction proceed on its own or would i have to heat or reflux it for it to proceed?

CHCl3 + 4NaOH → HCOONa + 3NaCl + 2H2O

The last step once the 68.00 grams of Sodium Formate is isolated, it is then reacted with 98 grams of Sulfuric Acid, This will produce 46.02 grams of Formic Acid along with 142.04 grams of Sodium Sulfate. Now my last question would be How would i separate the Formic Acid from the sodium Sulfate?

HCOONa + H2SO4 → CH2O2 + Na2SO4

Does this sound about right? Please do correct me if im wrong :) and if this thread belongs in Beginners and not here then feel free to move it :)

I make chloroform all the time by just placing a gallon of bleach in the freezer for 6 hours, then remove from freezer and drain off 150 ml, relace with 150 ml acetone, shake well for several minutes. Place outside for 14 hours with top loose on the jug. After 14 hours drain salt water from jug and chloroform is in the last two cups coming out of the jug. Place these two cups in a separatory funnel and remove chloroform, add 5 ml pure ethanol to stabilize and store in a air tight amber glass container. DONE AND SIMPLE

cal - 9-4-2012 at 07:09

Quote: Originally posted by Aqua_Fortis_100%  
Why not make it just from oxalic acid and glycerol? Much simpler..

Oxalic acid is OTC in most places and even if dont, you can make it from sawdust and NaOH or from sugar/HNO3..

http://www.homechemistry.org/view/Preparation_of_formic_acid

http://web.archive.org/web/20080424022524/http://www.frogfot...


Oxalic Acid is in Mrs. Stewart's Liquid Bluing.