Sciencemadness Discussion Board

document "formic acid to formaldehyde" in error?

Polverone - 5-2-2004 at 22:04

The Royal Society of Chemistry journal archives went online recently, and I've been browsing them. My school hasn't yet subscribed, but the abstract articles can be pretty detailed and are free to all. In any case, in more than one of these articles I read that the pyrolysis of calcium formate yields mostly methanol, with a relatively small amount of formaldehyde mixed in. Maybe this is simply a matter of varying experimental conditions, but still I found it discouraging from a preparative standpoint. All in all, it makes me wonder if I should leave the document, remove it, edit it, or reassess what the Library is and what it should be.

I'm still trying to figure out where I should go with the library. It would be nice to have an organized collection of preparations, demonstrations, and student-type investigations. But right now all it has is a few miscellaneous articles and a section that will soon be flooded with archaic books.

I like the idea that especially good posts or threads from the forum would be edited and turned into Library documents, but there's always something more pressing or interesting to take care of.

Ramiel - 5-2-2004 at 23:35

I think when I suggested the idea I siad I'd help to make it a reality. Just tell me what to summarise, aim and fire.

I'll put it in the same formatt as the other stuff I've submitted, just to be consisitent.

Sincerely
-Ramiel

BromicAcid - 8-2-2004 at 20:13

Quote:

.....reassess what the Library is and what it should be.


One thing that I've always wanted to see in the library are basically journals. From the people here.

For example, I've been keeping a written account of my attempts to make phosphorus, in it I have detailed descriptions of what I saw when certain reactions took place, what the results were, and what conclusions I came to alone with warnings. Then in subsequent writings to the document I changed things and it evolved. It should be completed this summer when I add the last two sections that I want to do, one 'perfected' version of the reduction of phosphates with an active metal, and one on the reduction of lead phosphate with hydrogen at 200C.

I just like to read what the people think about their reactions and their responses to them, not only are they interesting but you can learn a lot about what you really should expect from a reaction and you can choose modifications from what the people before you did. Basically anything that someone has tried at through several runs, like sodium production, or hydrazine, or some nitrations, how their procedures changed, that's one thing I would like to see there.

Formic acid to formaldehyde

trilobite - 20-5-2004 at 06:05

Polverone: According to US915946 that method for formaldehyde production can be get to work if the formaldehyde formed is sweeped from the reaction chamber with a carrier gas before it gets decomposed. Not an easy reaction I guess.

madscientist - 20-5-2004 at 07:26

I thought thermal decomposition of calcium formate yielded formaldehyde and no methanol. I don't see how it possibly could yield any methanol.

Formate Ion

Turel - 20-5-2004 at 11:37

Both are very possible and likely. Formate ion is a good reducing agent for carbonyl bonds. If formaldehyde was present through a reaction, it is very possible that formate ion reduces formaldehyde to methanol, itself becoming carbon dioxide. These type of auto-redox reactions are common with aldehydes and formic acid.

[Edited on 21-5-2004 by Turel]

PHILOU Zrealone - 21-5-2004 at 23:22

Formaldehyde is one of the most reactive aldehydes and it displays very strong reduction abilities....

Cannizaro's reaction works quite wel with bases...maybe that at the temperature of reaction...the CaCO3 suface is basic enough to help further oxydoredox...
Ca(O2CH)2 --> CaCO3 + CH2=O
CH2=O + CH2=O -base/heat/H2O-> CH3-OH + HCO2H

But in this case there is no water since water is forbiden in this reaction (formate must be very dry and anhydrous)...This will mean heat was too strong and CH2=O turns into CO2 to give all its H to the other CH2=O to form CH3-OH

The use of formate to make CH2=O is a waste of valuable formate since CH2=O can be made quite eqsyly from more available CH3-OH upon metal catalyst or with comon oxydisers.

Formate must be used to get the more valuable aldehyds of higher alkylic chain.