Sciencemadness Discussion Board

How to dissolve wood?

monolithic - 1-7-2019 at 14:32

Long story short, I'm doing essential oil extraction of wood. There's a piece of wood stuck in my round bottom flask - I guess it swelled up during the steam distillation process. It almost fits through the neck of the flask but gets stuck, and I can't break it up or pull it out. I'm currently letting it soak in hot (50 C) saturated NaOH with stirring. It doesn't seem to be doing much. Any other ideas?

SWIM - 1-7-2019 at 14:46

I'd try 10% bleach for a few days of soaking.

You could put the dry flask in an oven at 200 to 250C and try to carbonize it..

Concentrated H2SO4 might break it down.

monolithic - 1-7-2019 at 14:54

Good ideas, thanks for the quick response. I think I'll try H2SO4 first, since I have some drain cleaner sitting around.

WGTR - 1-7-2019 at 15:05

I’d suggest putting it in an oven and letting it dry out. If it swells in water, then without water it shrinks again...?

DavidJR - 1-7-2019 at 15:06

Burn it?

fusso - 1-7-2019 at 17:07

i dont think heating that hot is better than H2SO4. a bunch of organics like tar will stick to the flask. good luck in removing that unless you have piranha soln.

DraconicAcid - 1-7-2019 at 17:11

Copper(II) hydroxide dissolve in concentrated ammonia will dissolve cellulose- it might help break up the wood.

clearly_not_atara - 1-7-2019 at 17:49

Quote: Originally posted by DraconicAcid  
Copper(II) hydroxide dissolve in concentrated ammonia will dissolve cellulose- it might help break up the wood.

Ding ding ding! This is the original rayon process. It isn't used anymore because avoiding copper contamination of effluent is hard -- Cu(NH3)22+ is very stable and its salts are highly soluble.

There are also ionic liquids that can be used for dissolving cellulose. The anion is usually acetate, since it is a good H-bond acceptor. Cations are often imidazolium, though morpholinium, amidinium and choline have been used. Choline acetate in particular is accessible to the amateur, as is the DES choline chloride-urea. See:

monolithic - 1-7-2019 at 18:13

Thank you everyone for the interesting ideas. Some hot H2SO4 drain cleaner did the trick. :)

Mabus - 7-7-2019 at 07:44

Glad to hear. Sulfuric acid works best I see.

Magpie - 7-7-2019 at 16:09

Wood is disintegrated in pulp mills using aqueous NaOH/Na2S (Kraft process) at about 180°C for 3 hrs under pressure. This dissolves the lignin that binds the cellulose fibers together.

I would try heating it in aqueous NaOH (~25%) as hot as possible for a few hours.