eirikh96
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Methanol synthesis
Hello. Methanol can be made through destructive distillation of wood, hence the name "wood alcohol". How much heat should be provided in order to get
a reaction and is it enough to use a heating mantle that can reach a temperature of 300 - 400 degrees C?
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Tsjerk
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I'm not an expert on the subject, but my first findings of a quick search are that usually both sulphuric acid and high (7.5x atm) are used.
[Edited on 22-5-2014 by Tsjerk]
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Nicodem
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Thread Moved
22-5-2014 at 11:03 |
vmelkon
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Organic compounds tend to decompose above 200 C - 300 C.
I think a heating mantle would be slow. I would use a normal flame, such as by burning some wood.
I have done this once but I didn't pursue it.
I obtained a foul smelling odor and what looks like brown tar and water which perhaps contains methanol among other things.
| Quote: | | I'm not an expert on the subject, but my first findings of a quick search are that usually both sulphuric acid and high (7.5x atm) are used.
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From the videos that I have seen, it is done at 1 atm in a metal distillator and no H2SO4.
Can you provide the link that you found?
Perhaps the H2SO4 is suppose to accelerate the breakdown of the cellulose.
[Edited on 22-5-2014 by vmelkon]
[Edited on 23-5-2014 by vmelkon]
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macckone
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The following book has some information that may prove helpful:
http://books.google.com/books?id=DjMNAAAAYAAJ&printsec=f...
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leu
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The documents in the attached archive discuss many aspects of the pyrolysis of wood 
Attachment: WoodPyrolysis.zip (1.8MB)
This file has been downloaded 658 times
Chemistry is our Covalent Bond
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eirikh1996
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thanks for all information. Very important note: I am the same person behind eirikh96' profile but I had some password problems so I decided to start
a new user account since I was not able to access my previous account (eirikh96) and i never received password recovery email.
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aga
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Thanks for the wood pyrolysis paper link !
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Bert
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Ah, memories!
Mr. Chappell's 8th grade chemistry class- After we were assigned benches/seats, shown safety goggles and told when/how to wear them, the books were
handed out and the first hands on experiment was started the second day of class: "The Destructive Distillation of Wood". First we cut and bent some
glass tube and learned how to insert it safely into the stoppers to make the distillation apparatus...
A pile of the sort of sticks used for Popsicles or medical "tongue depressors" were weighed and then put into a long, large Dia. test tube, the
heating was done with alcohol lamps. We distilled them with a water cooled test tube as a receiver, first igniting the vapor driven off of the wood
pieces, then condenseing it and also doing several operations with whatever gases made it past the receiver- further ignition attempts, bubbling
through lime water and other reactive/reagent solutions.
The next couple of weeks were spent learning how to weigh, analyze and think deductively about the products of that single first lab. I was hooked at
the first day- Playing with fire. At school. Because I was TOLD TO. For class, you know...
Rapopart’s Rules for critical commentary:
1. Attempt to re-express your target’s position so clearly, vividly and fairly that your target says: “Thanks, I wish I’d thought of putting it
that way.”
2. List any points of agreement (especially if they are not matters of general or widespread agreement).
3. Mention anything you have learned from your target.
4. Only then are you permitted to say so much as a word of rebuttal or criticism.
Anatol Rapoport was a Russian-born American mathematical psychologist (1911-2007).
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Daffodile
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Here are some results (with photos) of my attempts to get Methanol from wood. I cut up an old evergreen stump, put them in an improvised setup, and
distilled some liquid. It smells like crap and is mostly water.
  
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aga
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Wow ! Reminds me - i really should take a peek at that jug of tarry stuff i got at the back of the shed.
Got it the same way and assumed it could be analysed/purified/used or something.
Time to bin or burn it.
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Metacelsus
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I think the wood is usually thoroughly dried (in an oven) before pyrolysis. If you didn't dry the wood, it's no wonder your distillate is mostly
water.
Also, does it literally or figuratively smell like crap?
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Daffodile
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It smells like musky burning, almost like a phenol synthesis gone wrong.
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Metacelsus
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The smell is probably due to guaiacol and/or syringol, from lignin pyrolysis:
https://en.wikipedia.org/wiki/Guaiacol
https://en.wikipedia.org/wiki/Syringol
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macckone
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Wood alcohol was usually made from low turpene hardwoods. Evergreens are a poor choice due to high turnene content. And drying at mid range
temperatures is essential to avoid too much water.
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Daffodile
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Yeah I'm drying it out now to try again soon, and I also have a better apparatus this time.
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Pumukli
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Earlier today I read an article about distilling wood. The yield regarding methanol was reportedly very low, the best run produced almost a whopping
2.5 percent solution from maple chips.
Maybe there is a better method for methanol synthesis for the amateur. (2.5 percent may be not bad if you are working on an industrial scale and
distill tons of wood every day.)
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