garage chemist
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Cellulose esters
There are a lot of organic acids which can form esters with cellulose, e.g. acetic acid and butyric acid. I have seen a lab scale preparation for
cellulose acetate from cellulose + acetanhydride (this is needed, acetic acid most likely won't work).
IIRC, cellulose can even form ethers with organic substances, I think cellulose + 1-chloroethane yields ethylcellulose and methyl chloride + cellulose
yields methylcellulose. Is this right?
I am thinking about esters of cellulose with inorganic acids. What about cellulose chloride (from cellulose + PCl3 or maybe anhydrous HCl gas)? This
is probably water sensitive and may be used to produce organic acid chlorides. If it could be made from cellulose + gaseous HCl we would have a
replacement for PCl3!  It would also be easier to use, since it's a solid
and forms normal cotton after the reaction (no distillation needed).
What about cellulose perchlorate? Now that would be some great guncotton! Preparation would be difficult though. I don't have an idea how this
could be done. 100% HClO4 explodes on contact with organic matter.
Are my ideas realistic?
What else could be done with the OH- groups of cellulose?
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Taaie-Neuskoek
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I've recently made some cellulose acetate, by adding cellulose (cotton-wool) to acetic anhydride and a small amount of
H<sub>2</sub>SO<sub>4</sub>.
Nothing happened, until I started to add a small amount of water. Hissing, warming up, and a strong pungent of acetic acid wat the result. I added so
much water until alle the cotton wool was dissolved. (outside...)
This is the end result:
Here's one pic of the acetating cotton-wool:
Never argue with idiots, they drag you down their level and beat you with experience.
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garage chemist
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Interesting!
What happened then?
Did the cellulose acetate dissolve in the water, or did it precipitate?
Did you follow a recipe or did you just try something out?
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Taaie-Neuskoek
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It is now a kind of resuspention in an erlenmeyer, it is a little heavier since the upper part of the suspension is clear now, although it is not a
phase-seperation.
I am going to let in damp in until it is a real sticky goo, and since cellulose acetate should have nice isolation characters, I'll try to
isolate a relay a little better with it.
The idea came from Jobbie, a mod on the the Dutch forum. He tried it with 80% acetic acid, but after a search by some members, we find out it must be
done by AA and H2SO4, so I tried out a quick and dirty experiment, since I have AA.
AA is btw an excelent liquid to determine or you have small cut's in your fingers
Never argue with idiots, they drag you down their level and beat you with experience.
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garage chemist
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I just made some cellulose acetate with my new Ac2O.
2g cleaned cotton (boiled in 2% NaOH for a few hours, washed and thoroughly dried) were added to 60ml GAA and 0,3ml H2SO4 (catalyst) in an erlenmeyer
flask.
(I was following a synthesis recipe, GAA is needed as solvent in the reaction.)
The mix was warmed on a water bath (35°C) and 15ml Ac2O were slowly added in small portions under constant stirring and kneading with a stirring rod.
After 10ml were added, the cotton suddenly started to become sticky and disintegrated into fibers which floated around.
After all Ac2O was added, most of the cellulose had dissolved.
After some more stirring and warming on the water bath (this time to 60°C), the rest of the cellulose dissolved and the liquid was clear and a bit
viscous, but the viscosity decreased again as the reaction went to completion (cellulose acetate is soluble in GAA, as you see).
A spatula of anhydrous sodium acetate was added to neutralise the H2SO4, and the mix was dumped into 400ml water in which a spatula of sodium acetate
was dissolved (buffer, to prevent hydrolysis of the ester).
The cellulose acetate precipitated as a white insoluble slime, was stirred some time and then filtered from the supernatant liquid and washed with
water.
It acted like a sponge and had lots of water adsorbed in it, the filtering went very slowly.
I put the slime into a cotton cloth and squeezed the liquid out of it, washed it again with water and again squeezed it.
It was put on the heater in my room to dry, it has formed a crumbly white mass.
When its dry I'll try to dissolve it in various solvents and make foils out of it (it is said to form transparent and flexible films very easily when
a solution of it is allowed to evaporate).
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virgilius1979
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Could you react cellulose acetate with Ba(ClO4)2 to produce cellulose perchlorate ?
Although I read that barium perchl. solubility is greater than Ba acetate... (wiki)
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Diablo
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MethyCellulose
I recently had the idea of making methyl cellulose by bubbling Hydrogen Chloride through methanol with some cotton in it. Does anyone know if this
would work?
[Edited on 20-2-2012 by Diablo]
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Velzee
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Quote: Originally posted by Diablo  | I recently had the idea of making methyl cellulose by bubbling Hydrogen Chloride through methanol with some cotton in it. Does anyone know if this
would work?
[Edited on 20-2-2012 by Diablo] |
Must the process remain anhydrous? If not, why not simply add a concentrated HCl or a small amount of concentrated sulfuric acid instead?
Check out the ScienceMadness Wiki: http://www.sciencemadness.org/smwiki/index.php/Main_Page
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aga
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Please do not pollute 4 year old posts if you have not bothered to actually try anything yourself.
Try it out: Do it anhydrous and then with some water present.
Report the results.
We all might learn something that way.
Edit:
If you are unable to try out your idea, just ask if anyone else is willing/able to try it out for you.
There are still quite a few active chemists here, one of which may take up the challenge.
[Edited on 28-8-2016 by aga]
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