Sciencemadness Discussion Board

Methanol -> methanal

Ramiel - 19-8-2002 at 02:14

I have already asked this question at an anarchy board, and no response save from MadScientist, so he reccomended that he come here.
I have great respect for this board already!
ok, here we go... verbatim:
Since formaldehyde (Methanal) is hard to buy because of restrictions [it being carcinogenic] and the lack of a good supplier in the first place, I want to manufacture my own. Two questions:

Because methanol is found easily, and is a primary alcohol (fast reaction); oxidizing it (e.g. with Cr^2O^7 2-) would yield a high purity methanal.
(1) The Cr^2O^7 needs to be acidified, would the H+ from 2 parts of Hydrochloric work just as well as the H+ from 1 part Sulfuric?

(2) Reaction:
3.(CH^3OH => HCHO + 2H+ + 2e-)
Cr^2O^7 2- + 14H+ + 6e- => 2Cr 3+ + 7H^2O
Is that right?

Don't use HCl!!!!

vulture - 19-8-2002 at 05:29

Please do not use HCl with a strong oxidizer like K2Cr2O7, KMnO4, H2O2, etc because this will yield toxic chlorine gas! I'm working on the equation, can't get it right aaargggh:mad:

vulture - 19-8-2002 at 06:09

Here's everything according to redoxtheory:

Cr2O7 +6e -> 2Cr 3+ X2
CH3OH -2e -> CH2O X6

So:

2Cr2O7 2- + 6CH3OH -> 4Cr +3 + 6CH2O

4- 12+
+16H+ +8H2O

follows:

2Cr2O7 2- + 6CH3OH + 16H+ -> 4Cr +3 +6CH2O + 8H2O

Total reaction:

2K2Cr2O7 + 6CH3OH + 8H2SO4 ->

2Cr2(SO4)3 + 6CH2O + 8H2O + 2K2SO4

We still miss 6 oxygens and 12H, but that nicely forms 6H2O so:

2K2Cr2O7 + 6CH3OH + 8H2SO4 -> 2Cr2(SO4)3 + 6CH2O + 14H2O + 2K2SO4


Done.

Obtaining methanal

Polverone - 19-8-2002 at 11:12

Okay, I see you are from Australia so unfortunately you maybe can't just get methanal from consumer products. But I am surprised that you would be able to get dichromates and not such a simple organic chemical! According to some resources I found, it is also possible to use KMnO4 for this oxidation. But in any case, methanal is fairly soluble in water and if you have an excess of oxidizing agent, it will be oxidized to formic (methanoic) acid. And if you have some formic acid along with your stronger acid and methanol all in solution, you may get some methyl formate (ester of methanol and formic acid) as well.

So as you can see it's not terribly simple. Why do you want methanal? Maybe there's a different way to obtain what you're after.

Two practical options

PrimoPyro - 19-8-2002 at 17:39

Copper Chromite and oxygen or vacuum,

or

Depolymerize common paraformaldehyde into formaldehyde. Just dissolve it in methanol and heat it. In many cases, paraformaldehyde works just fine as it is.

PrimoPyro

Ramiel - 20-8-2002 at 01:57

Yes, I understand about the oxidation of HCl now, thanks for that. The reason I was interested in using HCl or something similar is it's ease of aquisition and the fact that sulfuric catalyses the reaction between methanol and methanoic acid (resulting in the ester methyl methanoate), wheras HCl doesn't [ to my knowledge ].

I understand that if the experiment is conducted drop by drop, in a water bath at 80 C, then the formaldehyde is driven off as it is produced. This would stop much of it being further oxidised to the formic acid.

Thanks, that reaction concurrs.

In Australia, formaldehyde is classified as a dangerous carcenogen, therefore it is far beyond my means to get hold of any isomer of CH2O. I can, however get as much KMnO4 as I need from a friendly chemistry teacher. ;)

As for why I want formaldehyde? Well to preserve my victims, of course :D (manufacturing Research Department 'X)

vulture - 20-8-2002 at 05:46

I'm not sure, but IIRC KMnO4 will oxidize methanol to formic (methanoic) acid.

If your using conc. H2SO4, KMnO4 is a very dangerous option, not only because of the possible formation of Mn2O7, but also because the mixture could spontaneously ignite. I would then consider using H3PO4.

Using KMnO4...

Polverone - 20-8-2002 at 14:26

It may be that the dichromates are better oxidizers for this reaction. But aldehydes are so easy to oxidize that I think it will be easy to accidentally form HCOOH either way. I do know that when I did a quick web search I found a respectable looking page from an .edu site that said KMnO4 could be used as well as dichromates. Maybe it's not as effective but many people do not want to work with hexavalent chromium compounds because of their health and environmental effects.

Of course in neither case would you use concentrated acid with your oxidizing agent!
And if you do use KMnO4, save the precipitated MnO2 that you will get during the oxidation. It is much more active (at least when fresh) than the manganese dioxide that you might buy at a ceramics place or get out of old dry cells. It can be used as a mild oxidizing agent in its own right or used as the starting point for making many inorganic manganese compounds.

How to make Formaldehyde

Ramiel - 21-8-2002 at 02:53

Well, then it seems it is a bit of a challenge ;) I put it to your collective chemical genius. :)

by the way, we used fuming sulphuric in a lab at school with both Dichromate and Permanganate ions.

FUMING SULFURIC???

vulture - 21-8-2002 at 08:08

I'm sorry, but I find that very hard to believe. Fuming sulfuric acid is sulfuric acid with 20-60% SO3 dissolved in it, also called oleum, and is very difficult to safely manipulate. I doubt schools would allow students to work it, nor even have the money to acquire it, since it is expensive.

Fuming sulfuric acid with permanganate is asking for explosions, sponteanous ignition of anything just a bit flammable in the vicinity and production of ozone.

Ramiel - 22-8-2002 at 00:14

Fuming sulfuric, yep that's the stuff. There was only a v. small bottle of it, and we used a couple of drops.
Besides, we were working with alkenes, so there were no flames.

vulture - 28-8-2002 at 09:10

Besides, we were working with alkenes, so there were no flames.

Err, adding highly concentrated sulfuric acid to permanganate will cause Mn2O7 to form, a highly unstable and very strong oxidizer which decomposes explosively into ozone which then would auto-ignite anything flammable. Certainly if you're working with highly reactive alkenes!!!

Vulture is right

PrimoPyro - 28-8-2002 at 18:08

Also, very reactive ozonides will form upon treatment of alkenes with ozone gas. This is a very simple procedure known as ozonolysis. Ozonides of small alkenes are explosive and heat intolerant.

PrimoPyro

Ramiel - 29-8-2002 at 00:40

The stuff was a syrupy viscosity. Of course the oxidizers were in solution, and pretty dilute, but we added this conc. sulphuric (which was indeed fuming copiously) strait away. So, in Australia you're allowed to make ketones, play with ozone and learn how to make TNT, but not allowed within 100m of formaldehyde... lol.

Ramiel - 16-9-2002 at 06:21

I had thought of using a weak oxidizer such as H2O2 such that the reaction of methanol was not driven to the carboxylic acid product, and then I had a brain wave! how about using an inhibitor with a strong oxidizer or a catalyst with an even weaker oxidizer?

Here is a snippet of information I got from anguil.com which caught my eye;

In the formaldehyde production process, methanol reacts with air in the presence of catalyst to produce formaldehyde. Process yields are normally quite high, with over 95% - 98% of methanol ending up as formaldehyde.
[snip]
There is an exothermic/heat release of 300° F/149° C was expected during oxidation
[snip]
A precious metal catalyst was selected as the core of the catalytic system due to its ability to provide 98% DRE of the formaldehyde, methanol, dimethyl ether, and carbon monoxide at a catalyst bed inlet temperature as low as 500° F/260° C. The catalyst is deposited on a monolithic, honeycomb, stainless steel substrate. - I assume that simply a fine amount of this catalyst would be sufficient for lab manufacture.
[snip]
the required oxidation temperature is 500° F/260° C. The outlet temperature of the catalyst bed is approximately 800° F/427° C.
[snip]
The system operating provides well over the 98+% destruction efficiency required.

Any thoughts on adopting this method in the manufacture of methanal from methanol (wood alcohol)?

Electrolysis

Hoffmann-LaRoche - 16-9-2002 at 06:51

The steinberg-patent i`ve posted on the electrochemistry may be also interesting to you.
Although the production of methanol is the main purpose of the patent, it has to be noticed that formaldehyde, oxalic acid and glycollates also form as byproducts.
And the process is quite a simple one: no exotic electrodes(charcoal-electrodes with a big surface would do well..), K2CO3 as starting material(recycled in the process), air.
The most importent thing to keep in mind is the current density.
I dont know the limit of current density for this process, but it has to be kept so low, that no hydrogen develops.

Other methanol patents, just for knowing: US 4326041; US 4598061; US 5254520

HLR


trinitrotoluene - 18-10-2002 at 11:29

To obtain methanol is you can perform the destrutive distillation of wood. Or methanol can be extracted from solvents through distillation. I know here in the U.S some solvent called Denatured Alcohol have 90% *ethnol and about 10% methanol. Which can be isolated through distillation. But if you are doing that be careful Methanol is highly toxic.

Chambered - 27-10-2002 at 12:51

I believe he's trying to synth Methanal not aquire Methanol:P

Chambered - 27-10-2002 at 12:53

Also seperating EtOH and MeOH by disstillation is quite impractical.

Doesn't the reaction

Boob Raider - 27-10-2002 at 18:11

between acetone and bleach ..... if it is let to become hot .... produces methanal instead of chloroform.

catalytic dehydrogenation

blazter - 27-10-2002 at 18:45

speaking of conversion of methanol to methanal, is something i've researched a bit myself and am interested in too. probably the most useful but of information i found on the topic is in the pdf that i've attached. it shows experimental data on various catalyists for the conversions and reaction conditions. if one could construct an apparatus that passed methanol vapor + air over a catalyist one could have a LARGE amount of methanal if they wanted.

Attachment: methanol-CHOH.pdf (149kB)
This file has been downloaded 2033 times


Ramiel - 28-10-2002 at 00:38

That seems to be an interesting doccument after looking at it breifly, thanks.

by the way, boob raider, which bleach do you mean, sodium hypochlorite (household bleach), or chlorines, or what?

S.C. Wack - 1-8-2009 at 16:49

PREPARATION OF FORMALDEHYDE

In the usual way.

Attachment: jacs_42_867_1920.pdf (973kB)
This file has been downloaded 2520 times

Saw the name H. Adkins in Blazter's document and figured that this is a non-bullshit patent.

US19330613

[Edited on 2-8-2009 by S.C. Wack]

flyingbanana - 14-8-2009 at 19:35

Is starting from hexamine a viable preparatory method? I know the reaction with HCl has been used to make methylamine, but that's after a series of reactions, the first would be to form ammonium chloride and formaldehyde. One could probably filter off the ammonium chloride and then distill?

kclo4 - 14-8-2009 at 20:59

Trioxane is in fuel starter tablets and will produce anhydrous formaldehyde upon heating.
paraformalfdehyde and formaldehyde solutions are sold as champa-chem or something like that, they are dirty and need to be purified however.

S.C. Wack - 14-8-2009 at 21:10

Quote: Originally posted by kclo4  
Trioxane is in fuel starter tablets and will produce anhydrous formaldehyde upon heating.


Either that or it will distill unchanged at 115C, one or the other.

WTF does this have to do with oxidation of methanol?

unionised - 15-8-2009 at 05:16

I think he has got the wrong polymer of the wrong aldehyde.
If you heat metaldehyde (which is used as a fuel) it sublimes.
If you heat paraformaldehyde (which isn't used as a fuel as far as I know) you get fromaldehyde

chucknorris - 17-11-2012 at 19:19

Shouldn't you be able to do simple formaldehyde bubbler to purify paraformaldehyde directly into formaldehyde solutions up to 37% conc.? Shouldn't the formaldehyde solutions be suitable for most purposes (hexamine, pentaerythritol, etc.) used as so?

http://i48.tinypic.com/5bat3.png

SM2 - 17-11-2012 at 19:46

the easiest way to pure formalin solution, is to take a flask of methanol. Heat gently on sand bath, leading up to platinized asbestos or platinum gauze. All you have to do is warm the catalyst whilst the methanol vapor is consistently flowing over it, and lead the tube into some cold water. I think you'll get a standard 32 or 37% solution near room temp. saturation. After you heat the Pt to the required activation temperature, I believe the RXN is self sustaining, endothermic. Very smooth reaction, very pure product. You could almost as easily make acetaldehyde using everclear.

SM2 - 17-11-2012 at 19:56

Snip...

[/rquote]WTF does this have to do with oxidation of methanol?[/rquote] ....Snip

I got nothing against you, Wack, and it's really not my business to comment here. Just, you don't have to be an a-hole if you don't want to. That's all. Or maybe I got you all wrong. Maybe you honestly can't see the connection that although trioxane doesn't have anything to do with methanol, the author's end game was formaldehyde. Now, I bet my money you are smarter than that. So?

White Yeti - 27-11-2012 at 14:23

Here is an article on the synthesis of formaldehyde from methanol with sodium carbonate as a catalyst at 690 degrees centigrade:
http://infoscience.epfl.ch/record/84560/files/92_Su_ApplCata...

Carbon fibers are used as catalyst support.

SixTough - 7-1-2013 at 15:12

I think it was Norris' book on organic chemistry that suggests plainly heating copper rod to very hot and submerging it into methanol. No yields were stated but the simplicity is so pleasing.

I will try it some day (probably not soon) just because it is so incredibly simple :o

White Yeti - 8-1-2013 at 19:38

It sounds tempting, but it's a very bad idea. Think of how the methanol would burst into flames^^ and how you could get intoxicated by methanol vapours.

I don't see the difficulty in obtaining copper oxide, I have a few grams of the stuff from the decomposition of copper carbonate. If I knew how to, I would have mounted some of it onto a support to make a catalyst, and presto! Formaldehyde synthesis for the amateur.

Just wondering, does anyone know the conditions under which aqueous formaldehyde will condense to paraformaldehyde? I would really like to try this out, but for handling purposes, I would prefer to make trioxane or paraformaldehyde, even if this requires an extra step. Wiki said that paraformaldehyde forms spontaneously in aqueous solution, but I seriously doubt that is an efficient synthesis route.

Mailinmypocket - 9-1-2013 at 10:53

Quote: Originally posted by SixTough  
I think it was Norris' book on organic chemistry that suggests plainly heating copper rod to very hot and submerging it into methanol. No yields were stated but the simplicity is so pleasing.

I will try it some day (probably not soon) just because it is so incredibly simple :o


I've done this many times, the methanol never ignited but I don't know how many times you need to dunk the copper into the alcohol to have any appreciable amount of anything form. It does make a faint formaldehyde smell though.

nezza - 9-1-2013 at 11:53

I would be interested in knowing more about the oxidation of methanol. I have prepared acetaldehyde by distilling it out of acidified ethanol/dichromate (sulphuric acid), but substitute methanol for the ethanol and very little formaldehyde is formed. why ?.

White Yeti - 12-1-2013 at 15:25

That's a tough question. Preparing acetaldehyde is already quite a challenge:
http://www.sciencemadness.org/talk/viewthread.php?tid=55

Do you mind providing more details on your procedure for making acetaldehyde? (amounts of reagents used, temperatures, yields, that sort of stuff) I'd be really interested to know.

I might be attempting a synthesis of formaldehyde soon. I'm working out the technical details and trying to find a way to do this safely. The whole process is a bundle of danger; flammables, volatile carcinogens, high temperatures, and hydrogen gas.

S.C. Wack - 12-1-2013 at 18:55

Typical procedure, from Hale in SM library: Methyl alcohol (100 ml) is placed in a flask which is kept at a temperature of 40°, and connected to a horizontal combustion tube in which a roll of copper foil (5 cm. long) is placed. The other end of the combustion tube is connected to a condenser and a well cooled receiver.

A stream of air is driven through the alcohol causing a mixture of air and alcohol vapour to pass through the copper coil, which should be heated until it just glows. The reaction will proceed without further heating and a solution of formaldehyde in methyl alcohol will collect in the receiver.

Small explosions on the copper do no harm; but the temperature should not exceed a dull red heat or some of the aldehyde will be decomposed.

A much improved yield (about 80 per cent.) may be obtained by substituting pumice, coated with a mixture of silver and copper, for the roll of copper foil.


Perhaps this refers to precipitated metal.


Quote: Originally posted by SM2  
Just, you don't have to be an a-hole if you don't want to.

Oh, I want to. Maybe, though it will never be PC, it may be best if someone is, someone not having to represent the staff, in the best interests of a semi-serious science forum/information depository with 18989 threads and over a quarter million posts. This is nothing new for anyone who has accidentally read several of my posts. I'm a smartass by nature and others for sure are not good at it, and obviously a lifelong antisocial type.

There are threads that are much too long, see them. This is obviously a narrowly defined one, yet we want to start new branches of discussion in it like trioxane and preparation of acetaldehyde and paraformaldehyde (which belong in and already are in appropriate threads). If you support this, that's your problem, I want no part of it. Explanation seemed unnecessary.

AJKOER - 18-1-2013 at 18:31

Quote: Originally posted by blazter  
speaking of conversion of methanol to methanal, is something i've researched a bit myself and am interested in too. probably the most useful but of information i found on the topic is in the pdf that i've attached. it shows experimental data on various catalyists for the conversions and reaction conditions. if one could construct an apparatus that passed methanol vapor + air over a catalyist one could have a LARGE amount of methanal if they wanted.


Iron (III) oxide is a cited catalyst. One way to prepare, perhaps by dissolving Fe in Oxalic acid. Separate out the FeC2O4 (avoid an excess of H2C2O4 as it would complex back into solution) and heat. The thermal decomposition of Iron oxalate produces a very fine form of FeO and Fe (actually burns in contact with air). Further heating can form Fe2O3 (see "Thermal decomposition of ferrous oxalate dihydrate studied by direct current electrical conductivity measurements" by K. S. Rane, A. K. Nikumbh and A. J. Mukhedkar, link http://link.springer.com/article/10.1007%2FBF01113573?LI=tru... ). Well, at least, this is a possible route to an Iron (III) oxide catalyst.
---------------------------------------------------------------------------------------

For Copper oxalate's thermal decomposition as a source of fine Cu, please see "The thermal decomposition of copper (II) oxalate revisited" by Emmanuel Lamprecht, Gareth M. Watkins and Michael E. Brown. Link: http://eprints.ru.ac.za/436/1/Lamprecht_The_thermal_decompos...


[Edited on 19-1-2013 by AJKOER]

White Yeti - 19-1-2013 at 06:05

I must ask, why go through all the trouble of making oxalates? There are much simpler ways to obtain iron oxide, and copper oxide can be obtained by decomposing its carbonate. If it's to obtain a finely divided powder, it's not worth it, that's what the mortar and pestle is for. If all else fails, use two sheets of paper and a hammer.

I'll tell you what the real challenge with this synthesis is, to do it safely and controllably. Making the catalyst is no problem, even sodium carbonate can be used. What would be useful to know is how to mount the catalyst into a tube of some sort.

roXefeller - 29-12-2013 at 18:48

Quote: Originally posted by S.C. Wack  
A stream of air is driven through the alcohol causing a mixture of air and alcohol vapour to pass through the copper coil, which should be heated until it just glows.


A little word of caution on this for anyone who tries it. The chemicals contained in this are flammable, and with the air bubbling, they are getting mixed with O2. So the tubing has a potential of air/fuel explosive. Having an open flame for heating can be the initiator. If its glass equipment you don't want to be near it should it go off. Take precautions.

S.C. Wack - 30-12-2013 at 14:56

Quote: Originally posted by roXefeller  
If its glass equipment you don't want to be near it should it go off. Take precautions.


The combustion tubes of yesteryear were porcelain, 2-5 mm thick walls.

roXefeller - 31-12-2013 at 15:52

I'd probably use a brass tube to do this, as its easy to heat and has more copper for the catalysis, but any other glassware in the setup is still a danger.

macckone - 31-12-2013 at 17:55

Combustion tubes can be wrapped with very fine piano wire to reduce the explosion hazard. It was used in the stanley steam boilers. This doesn't eliminate the hazard.

Omniquist - 10-2-2018 at 19:49

Hi, I'm very new here. Due to my condition and living arrangement I can only use that which is otc or inexpensive. So I'm curious: could the cleaning material known in America as "chore boy", a copper wire padding similar, at least in concept, to steel wool, be used as the catalyst? I would imagine that, like steel wool, this material would be coated in some form of protectant so would possibly need to be checked for, perhaps a paraffin. i can't recall a time when I ever saw any with an oxidized appearance. It's the closest thing I can imagine to as "copper gauze" and I don't have any silver wire, at least, not to my knowledge. I've personally reduced oxides on copper by dipping hot copper, not even red hot (at least that I could see) into methanol and it came back shiny as if new. This was a few old pennies I'm speaking of and nothing more. Ives learned so much since I've found this forum. Thank you for your wisdom and your time.

S.C. Wack - 11-2-2018 at 07:34

The wise let me overhear them saying how you have been elected to determine the optimum packing and surface area of the Cu for yield. There is a touch of machine oil on Chore Boy, and 3M's item is something with a copper coating.

Photosensitive - 13-2-2018 at 16:35

Quote: Originally posted by Mailinmypocket  
Quote: Originally posted by SixTough  
I think it was Norris' book on organic chemistry that suggests plainly heating copper rod to very hot and submerging it into methanol. No yields were stated but the simplicity is so pleasing.

I will try it some day (probably not soon) just because it is so incredibly simple :o


I've done this many times, the methanol never ignited but I don't know how many times you need to dunk the copper into the alcohol to have any appreciable amount of anything form. It does make a faint formaldehyde smell though.


Wrong quot sorry

[Edited on 14-2-2018 by Photosensitive]

Photosensitive - 13-2-2018 at 16:38

Quote: Originally posted by S.C. Wack  
Typical procedure, from Hale in SM library: Methyl alcohol (100 ml) is placed in a flask which is kept at a temperature of 40°, and connected to a horizontal combustion tube in which a roll of copper foil (5 cm. long) is placed. The other end of the combustion tube is connected to a condenser and a well cooled receiver.

A stream of air is driven through the alcohol causing a mixture of air and alcohol vapour to pass through the copper coil, which should be heated until it just glows. The reaction will proceed without further heating and a solution of formaldehyde in methyl alcohol will collect in the receiver.

Small explosions on the copper do no harm; but the temperature should not exceed a dull red heat or some of the aldehyde will be decomposed.

A much improved yield (about 80 per cent.) may be obtained by substituting pumice, coated with a mixture of silver and copper, for the roll of copper foil.


Perhaps this refers to precipitated metal.


Quote: Originally posted by SM2  
Just, you don't have to be an a-hole if you don't want to.

Oh, I want to. Maybe, though it will never be PC, it may be best if someone is, someone not having to represent the staff, in the best interests of a semi-serious science forum/information depository with 18989 threads and over a quarter million posts. This is nothing new for anyone who has accidentally read several of my posts. I'm a smartass by nature and others for sure are not good at it, and obviously a lifelong antisocial type.

There are threads that are much too long, see them. This is obviously a narrowly defined one, yet we want to start new branches of discussion in it like trioxane and preparation of acetaldehyde and paraformaldehyde (which belong in and already are in appropriate threads). If you support this, that's your problem, I want no part of it. Explanation seemed unnecessary.


How can i make a 37% or 32% formaldehyde in water out of the methyl alcohol formaldeyhde solution which i get in the recieving flask Thanks!

Omniquist - 2-3-2018 at 08:17

Hi everyone. I searched a little bit and I remember somebody saying they wanted to make formaldehyde, somebody else recommending pcc, and then the other person responding that they can't get that in their country. I apologize if this is the wrong forum, as I can't seem to find that exact conversation. Anyways, I found an otc source of pyridinium chlorchromate, though I don't know the concentration and I don't know the price, as I've never needed to put myself into a situation where I'd need to purchase such a product. Anyways, this pcc is found in a certain in vitro urine test adulterant likely sold at a "tobacco" shop near you. Most of these tests involve the use of oxidizers, one being nitrites, one being peroxide/per oxidase, and one that made me sit up, pyridinium chlorchromate. The name of the brand that has the pcc is "urine luck". I'd like to be able to tell you with absolute certainty the percentages, the likelihood of success with the use of this, and the price (which I suspect could be ridiculous. I've heard stories that put the price range for these things near 40 us$, and it's not a pure substance. Anyways, I hope this helps you on your journey toward whatever experiment you are interested in attempting. Just be safe, likely you already know, but formaldehyde is often labeled as carcinogen. Chromates aren't exactly nontoxic either (see Erin brockovich). Anyways, hope this helps.
Ps, btw, if you have a "GNC" store near you, or equivalent, perhaps you can find it there. I haven't subjected myself to their extortionist pricing in some time.

[Edited on 2-3-2018 by Omniquist]

Daffodile - 9-8-2018 at 08:44

Attempted synthesis of formaldehyde through copper catalyzed oxidation of methanol.

Methanol was boiled in a flask and air was pumped in to mix with the vapour. This was pushed through a thin copper tube heated to red hot, and bubbled through water.

Formaldehyde was noticable at the beginning of the synthesis (odor) but was not produced in great amounts after that.

It overheated and exploded once, not as bad as last time.

A valve was put on the pump intake to limit airflow as too much pressure would cause the flask stopper to pop off.

IMG_0464.JPG - 2.4MB

Daffodile - 23-8-2018 at 11:45

Okay so the catalyzed conversion from methanol is certainly impractical for most amateurs, so Ill be looking into formaldehyde production by either electrolysis or destructive distillation of formates. Im surprised there hasnt been more work done on this by SM given the practical uses of formaldehyde and the amount of effort put into tetrazoles etc.

nleslie321 - 23-8-2018 at 21:46

formaldehyde is a category 2 chemical in Australia so can be purchased without a EUD if you have an account with the said supplier.
There are quite a few suppliers who will sell to individuals just sort through the suppliers on google. i wont say which ones but there are a few and
also you have the option of overseas ordering off ebay. As far as i can see there is no requirement for permits/licenses for import of most chemicals and it is just a
law regarding Australian businesses that require you to have an account to purchase category 2 and must sign an EUD for cat 1 chemicals. As long as your not buying direct
drug precursors or chemical weapon precursors etc which you can see do require import licenses then your ok.

Quieraña - 24-8-2019 at 20:26

I was reading in the SM Library about the catalytic oxidation of compounds in the vapor phase. This book delved into the use of silver especially in the Practical manufacturer of formaldehyde on an industrial scale. It would seem that the person above the last with the picture was on the right track in the beginning of the reaction. He or she said that they had heated there copper tubing to Red Hot and I'm curious if you may be overheated it because it sounded like you were producing from the outset but that this did not continue throughout. Also if I remember correctly there was a loop to recycle the vapors that did not form into formaldehyde (in the book) but I'm not sure. again check that book out it was a definite answer to your questions.