Sciencemadness Discussion Board

Methanol synthesis

eirikh96 - 22-5-2014 at 06:11

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?

Tsjerk - 22-5-2014 at 06:27

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]

vmelkon - 22-5-2014 at 11:27

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.


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]

macckone - 22-5-2014 at 15:58

The following book has some information that may prove helpful:

http://books.google.com/books?id=DjMNAAAAYAAJ&printsec=f...

leu - 22-5-2014 at 17:46

The documents in the attached archive discuss many aspects of the pyrolysis of wood :cool:

Attachment: WoodPyrolysis.zip (1.8MB)
This file has been downloaded 650 times


eirikh1996 - 4-6-2014 at 11:05

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.

aga - 4-6-2014 at 15:12

Thanks for the wood pyrolysis paper link !

Bert - 4-6-2014 at 16:14

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...

Daffodile - 12-3-2016 at 09:48

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.

IMG_20160311_155821_1.jpg - 842kBIMG_20160311_165344.jpg - 601kBIMG_20160311_164238_1.jpg - 955kB

aga - 12-3-2016 at 11:28

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.

Metacelsus - 12-3-2016 at 15:00

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?

Daffodile - 12-3-2016 at 15:02

It smells like musky burning, almost like a phenol synthesis gone wrong.

Metacelsus - 12-3-2016 at 15:05

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

macckone - 12-3-2016 at 18:20

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.

Daffodile - 13-3-2016 at 08:09

Yeah I'm drying it out now to try again soon, and I also have a better apparatus this time.

Pumukli - 13-3-2016 at 09:38

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.)