mick
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Ion exchange resins
I have not had much to do with ion exchange resins short of purifying water. Recently, I have used a strong base type to do an organic deprotection,
to take of a toluoyl group, and cyclisation and it worked brilliantly. Everyone else has used NaOH plus heat and neutralise with acid and all the work
up with a 60-80% yield. Using this resin in methanol did the reaction faster and at room temp and the only by-product was the methyl ester of toluic
acid, which sublimes under a bit of vac, did not even have to take it out the flask. It is the first organic reaction that I can honestly say I have
got 100% yield.
Would they be any good in general chemistry where you can filter of the acid or alkali ?
mick
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Tacho
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I have read somewhere the very alkaline ones, like yours, would be able to act as catalyst in the transesterification needed to obtain biodiesel.
I'm very interested in a solid non-soluble catalyst for this reaction. So are three million scientists all over the planet.
Is there a common (not-Aldrich) source for this resins? Can they be made at home?
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FrankRizzo
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Ion-Exchange resins are pretty easy to find (in the US anyway). Like Tacho said, they're sold for use in water purification units (softeners,
iron removal, etc).
Try: http://www.resindepot.com
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chemoleo
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Mick, I am not sure I understand your post, and the reactions you did. What exactly did you do? What is are your resin beads (some polysaccharide?),
and how did you link the alkaline groups to it? What are they?
I am only familiar with ion exchange resins in the biochemical field, in that case, basic ones are those with i.e. diethylamine linked straight to
agarose beads (polysaccharide).
Tacho, re. catalysis of biodiesel production: In the respective Biodiesel thread, the person who did the experiments (see my very first post in that
thread) actually tried this, with a variety of resins from sigma. However, and unfortunately, he couldn't get catalysis to work. Seems unlikely
that water purifier ion exchange resin will work instead 
Never Stop to Begin, and Never Begin to Stop...
Tolerance is good. But not with the intolerant! (Wilhelm Busch)
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Tacho
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| Quote: | Originally posted by chemoleo
Tacho, re. catalysis of biodiesel production: In the respective Biodiesel thread, the person who did the experiments (see my very first post in that
thread) actually tried this, with a variety of resins from sigma. However, and unfortunately, he couldn't get catalysis to work. Seems unlikely
that water purifier ion exchange resin will work instead |
My insistence in thinking I can find a better catalyst for this reaction may be because of THIS, but may also be because I have a project where ricin oil and ethanol spend hours mixed at about 50º. So, if the damm things are already hot
and mixed, why not go a step further and transesterificate the cocotion? European and american research don't pay much attention to ricin oil or
ethanol in biodiesel production, for economic reasons. Ricin oil has an odd behavior in so many aspects, maybe I can find another odd behavior of it.
Thank you anyway.
Edit: And by the way, I would like to know how to MAKE them, so I could push them to the very alkaline (cationic?anionic?) side. Anybody?
[Edited on 30-9-2004 by Tacho]
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mick
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What I did,
I found some Dowex resin which was marked up as strongly basic but is as the chloride. I stirred it with 2M NaOH, filtered and washed it with water
until neutral. Washed it with MeOH and then used it.
I found some stuff in the literature where they had used this stuff at over 100oC but the technical literature gives 50 or 60 oC as the max temp
mick
The strong alkali ones are tetraalkylammoniun ions attached to the resin, I think.
The actual reaction was to deprotect a deoxy-ribose sugar bit which was coupled to a substituted imidazole which could cyclise to give an imidazolo
pyridine ring system.
And everything happened.
[Edited on 30-9-2004 by mick]
[Edited on 30-9-2004 by mick]
[Edited on 30-9-2004 by mick]
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cagiano
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ion exchange resin
| Quote: | Originally posted by Tacho
| Quote: | Originally posted by chemoleo
Tacho, re. catalysis of biodiesel production: In the respective Biodiesel thread, the person who did the experiments (see my very first post in that
thread) actually tried this, with a variety of resins from sigma. However, and unfortunately, he couldn't get catalysis to work. Seems unlikely that
water purifier ion exchange resin will work instead :( |
My insistence in thinking I can find a better catalyst for this reaction may be because of THIS, but may also be because I have a project where ricin oil and ethanol spend hours mixed at about 50º. So, if the damm things are already hot
and mixed, why not go a step further and transesterificate the cocotion? European and american research don't pay much attention to ricin oil or
ethanol in biodiesel production, for economic reasons. Ricin oil has an odd behavior in so many aspects, maybe I can find another odd behavior of it.
Thank you anyway.
Edit: And by the way, I would like to know how to MAKE them, so I could push them to the very alkaline (cationic?anionic?) side. Anybody?
[Edited on 30-9-2004 by Tacho] |
we tried to transesterificate rapeseed oil with methanol and a strong basic resin. we were'nt able to see any reaction. i suppose some steric
exclusion. i wonder if somebody obtained some result.
ricin oil has too hi iodine number i.e. too many double bonds so can polimerize oxidize: not acceptable according european rules
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Bill
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Look on Ebay. Use keywords like Dowex, Amberlite, etc.
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