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Baphomet
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Substitute for dioxane
I'm about to run out of 1,4-dioxane which is a wonderfully toxic and versatile polar aprotic solvent that is now hard to find outside of chemical
suppliers.
Are there any good substitutes? Note that I'm not just after dissolution ability but a low level of chemical reactivity. I'm here scratching my head
but all the other solvents that fit the bill are even less 'OTC' than dioxane.
\"Who ARE you? You\'re like the drummer from REO Speedwagon - nobody knows who you are\" from \'Employee of the Month\'
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Ozone
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How about glyme (1,2-dimethoxyethane)?
-Anyone who never made a mistake never tried anything new.
--Albert Einstein
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BromicAcid
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How about making it? Frogfot had a good procedure for it when his site was up, still available by the wayback archive:
http://web.archive.org/web/20071011001804/www.frogfot.com/sy...
Dioxane is pretty toxic but it's all relative compared to what you're using it for obviously. When my I told my doctor I was a chemist he was worried
about exposure to solvents, little did he know what nasties I use the solvents with.
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garage chemist
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There is a german synthesis of dioxane on Lambdasyn which is similar to frogfots method, but uses a mix of 225ml ethylene glycol and 6ml sulfuric
acid. Quite surprising how little acid is needed to make this ether.
Whether you can find a substitute depends on the application.
Glyme and Diglyme sound good, but they're hard to get (for me at least) and can't be made at home (well, unless you're prepared to methylate glycol or
diglycol with dimethyl sulfate).
Normally I would recommend dioxane as a substitute for glymes.
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Baphomet
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Thanks guys! I like that synth.. will try it out and report the results later.
\"Who ARE you? You\'re like the drummer from REO Speedwagon - nobody knows who you are\" from \'Employee of the Month\'
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maxidastier
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Does it make sense to carry out the synthesis under lower pressure to minimize the formation of those nasty by-products?
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blogfast25
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Where precisely? I looked for it sometime ago and couldn't find it!
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garage chemist
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It's here:
http://www.lambdasyn.org/synfiles/dioxan.htm
It's a lot of work even if it seems easy. Several treatments with KOH are necessary to seperate most of the water. If there's a better way to remove
large amounts of water from dioxane, I'd like to know it. CaCl2 forms a complex with dioxane.
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maxidastier
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| Quote: |
If there's a better way to remove large amounts of water from dioxane, I'd like to know it.
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Molecular Sieve 4A... for 1 liter around 100g
But still:
| Quote: |
Does it make sense to carry out the synthesis under lower pressure to minimize the formation of those nasty by-products?
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[Edited on 15-7-2011 by maxidastier]
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plastics
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I have done the frogfot method with 1000ml MEG and got approx 400ml of very dry dioxane
Don't overdo the sulphuric acid as mentioned otherwise you end up with black goo very quickly
As garage chemist says it is quite an effort to get all the water out and you get a fair amount of sticky orange polymerised ethanal as well
As the frogfot method states use a Vigreux column for the initial separation and distil the final nearly dry product off Na metal or KOH. Judging by
the BP and smell (!?) of the final product it seems quite pure
[Edited on 15-7-2011 by plastics]
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DJF90
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I suspect p-TsOH can be used to advantage in place of sulfuric acid. You should get less charring and higher yields, as the acid is not dehydrating or
oxidising. MsOH may also find use in this synthesis.
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maxidastier
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I know that it works better with p-TsOH, but I simply cannot get that stuff...so
Does it make sense to carry out the synthesis under lower pressure to minimize the formation of those nasty by-products?
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blogfast25
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The frogfot procedure uses K2CO3, IIRW...
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not_important
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Quote: Originally posted by maxidastier  | I know that it works better with p-TsOH, but I simply cannot get that stuff...so
Does it make sense to carry out the synthesis under lower pressure to minimize the formation of those nasty by-products? |
Can you get toluene?
http://www.sciencemadness.org/talk/viewthread.php?tid=11878
Even crude TsOH, containing some o- and m- isomers, generally is OK for use as a catalyst.
Higher yields of the para isomer are obtained by passing toluene vapour through H2SO4 at 150-160 C, with excess toluene removing the water formed as
the azeotrope, taking care to stop at about 95% conversion of the H2SO4 (measure the amount of water distilled off) to minimise poly-sulfonation.
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maxidastier
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No, I can not get toluene. It's restricted in Germany for "common people". Fuck it!
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blogfast25
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If it 'works better' with TsOH, what precisely does that mean? In what respect is it preferable to conc. H2SO4 that justifies making the TsOH in the
first place? In what way would the synth. of dioxane be modified, using TsOH instead of conc. H2SO4?
[Edited on 19-7-2011 by blogfast25]
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DJF90
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If you read my post you'll notice I mention the criteria on which TsOH makes a better catalyst. Its a non-oxidising, non-dehydrating acid with a pKa
similar to that of sulfuric acid. This means you'd expect a cleaner reaction and as such a higher yield of the deisred product.
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tmb
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What is the yield with TsOH?
Is a dehydrating acid not preferred? Since the aim is to remove water?!
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maxidastier
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| Quote: |
1,4-dioxane was synthesis by dehydration of ethanediol using p-toluene sulphonic acid as the catalyst.Influence of catalyst dosage,reaction
temperature and reaction time on the yield was investigated.The optimum reaction condition was as follows: catalyst dosage=4.3% of the amount of
ethanediol,reaction time 50 min.1,4-dioxane yield of 84.82% was obtained under the optimum condition. |
http://61.185.219.126:88/qikan/epaper/zhaiyao.asp?bsid=14647
Can someone get that paper or tell me how to do it?
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maxidastier
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ok, then. How many grams of TsOH would you use for dehydrating 200ml ethanediol?
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Nicodem
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Hm, have you bothered reading that abstract you quote? It says it all right there!
You click on the link for the full text and it downloads. You need a PDF viewer installed to view the article.
PS: Are you sure you are able to conduct chemical experiments safely? I would suggest you to first work on your general skills.
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DJF90
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I've just checked myself what the issue is and it won't allow you to download. Anyone have access?
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Nicodem
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| Quote: Originally posted by DJF90 | | I've just checked myself what the issue is and it won't allow you to download. Anyone have access? |
Could be IP country dependent. Looks like the Chinese like my IP:
Attachment: gych02006.pdf (349kB)
This file has been downloaded 859 times
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DJF90
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Thanks - no good to me as its only the abstract in English. Should be sufficient to give it a go if necessary though.
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maxidastier
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Thank you anyway Nicodem. I'm not that stupid as it seems. I just don't like making experiments with only an abstract 
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