Author Topic: Easy Formalehyde Synth. with a catch  (Read 382 times)

Douchermann

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Re: Easy Formalehyde Synth. with a catch
« Reply #40 on: September 30, 2009, 07:25:40 AM »
I think the main issue is the heat transfer vs. how much heat is generated.  Might I suggest a different approach. 

Have a copper pipe sealed to an addition/separatory funnel at one end.  Heat a decent length of the copper with a torch and allow the methanol to slowly flow in.  I do not like the procedure on frogfots page.  The entire apparatus has many superfluous elements for such a fundamentally simple process.  As long as one end is sealed against the separatory funnel, positive pressure should be generated.  Enough to bubble the gas into water.  Might be more advantageous to run the stream through a condenser before hand to eliminate any methanol passover.

Prepuce1

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Re: Easy Formalehyde Synth. with a catch
« Reply #41 on: October 01, 2009, 04:23:53 AM »
I think the main issue is the heat transfer vs. how much heat is generated.  Might I suggest a different approach. 

Frogfoot's method was just demonstrating the effect (that I haven't been able to get), so he's not worried about capturing a product. I though his site was pretty interesting overall.

Your explanation for the fact that I haven't created a truly self sustaining reaction makes a lot of sense, and I like your idea using the sep. funnel. If I understand correctly there would be no way for oxygen to get in to the reaction area, though, and it's needed. Did I misunderstand?

PP

Prepuce1

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Re: Easy Formalehyde Synth. with a catch
« Reply #42 on: October 01, 2009, 04:27:46 AM »
I will open a whole threed soon as I want the input of the community before I release my current method for making glacial acetic acid from an (aq)solution of AcOH.

I'll be looking forward to that one!

PP

Douchermann

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Re: Easy Formalehyde Synth. with a catch
« Reply #43 on: October 01, 2009, 04:59:08 AM »
Actually I don't believe oxygen to be completely necessary.  CH3OH -----> CH2O + H2.  The presence of oxygen just creates water which is where the bulk of the exotherm comes from.  The method I proposed would require constant temperature control, as opposed to letting the reaction generate the heat required.  This method was used industrially for quite some time. 

Prepuce1

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Re: Easy Formalehyde Synth. with a catch
« Reply #44 on: October 02, 2009, 02:38:39 AM »
That's interesting. I would have never thought of it on my own.

In addition to your recommendation, I would think that we might be back to where an electrically heated wire in an environment lacking oxygen might be feasible.

In the method you suggest, BTW, how closely do you think the temperature would need to be controlled, and what would that temperature be?

PP

eesakiwi

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Re: Easy Formalehyde Synth. with a catch
« Reply #45 on: October 14, 2009, 04:15:58 AM »
I haven't read every post here but...

 In a science book I have, theres a picture of someone holding a bunch of red hot copper coins in the fumes of hot Acetic acid.

 The hot Copper metal acts as a catalyst & they stay red hot in the Acetic acid fumes.

 This is sorta like those jet flame lighters, where if you heat the tiny wire above the nozzle red hot, then let a small flow of gas excape without the flame, & the wire stays red hot.

 I'm guessing Acetic acid gets changed to Acetic anhydryde in the same way as Methanol changes to Formalehyde (& Butane changes to ? in the presence of red hot Palladium coated wire)

Vesp

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Re: Easy Formalehyde Synth. with a catch
« Reply #46 on: October 16, 2009, 11:22:08 PM »
I doubt it gets turned into acetic anhydride - I think that reaction would be exothermic, wouldn't it?
It perhaps just oxidizes, keeping the Cu red, and producing CO2, H2O, etc with out the flame.
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