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chemrox
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Hey not_, why is this so?
"Pre-WW2 books are the best bet for this sort of method, pre-Depression a even better bet. "
Any particular books in mind?
"When you let the dumbasses vote you end up with populism followed by autocracy and getting back is a bitch." Plato (sort of)
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Nicodem
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| Quote: | Originally posted by Ephoton
I would like to know if it is possible to swap alkyl chains on alkoxides and how it is done if
it is possible.
eg. 
sodium ethoxide + ?????????? ----> sodium methoxide. |
You can not literally "swap alkyl chains on alkoxides" but you can do an normal proton exchange to get the same result. If you dissolve your NaOEt in
a large excess of dried methanol, rotavap the solvent, add again some methanol and rotavap again you should obtain a fairly pure NaOMe (depending on
what you want to use it for). In theory, if in addition to methanol you add a solvent that forms an azeotrope with ethanol (but not methanol) and
distil to half volume using a distillation column, followed up by completely drying on a rotavapor, you should be able to obtain very pure NaOMe in
one go, yet I don't know what kind of solvent would fit such a requirement.
Obviously, all this even if efficient is actually pointless as it easier to prepare NaOMe from NaOH and MeOH trough azeotropic removal of water or
simply by drying the NaOH/MeOH solution with 3A molecular sieves. There was quite some discussion on the forum about the many possibilities.
(Disregarding the fact that NaOMe is commercially available, not regulated and almost as cheap as NaOH).
Care should be taken in rotavaping sodium alkoxides to dryness. Always remember that heat, sodium alkoxides and oxygen is a good recipe for ending up
in flames.
…there is a human touch of the cultist “believer” in every theorist that he must struggle against as being
unworthy of the scientist. Some of the greatest men of science have publicly repudiated a theory which earlier they hotly defended. In this lies their
scientific temper, not in the scientific defense of the theory. - Weston La Barre (Ghost Dance, 1972)
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Ephoton
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a lot of older books chemrox are easier to use in our case as they were well
before some of the more technical industrial methods.
Nicodem exactly what i NEEDED thanx dude as always.
a thought depending on the size of your pocket the azeotropic
solvent realy only needs to absorb more ethanol than methanol.
not that hard realy. ethyl acetate I belive will do this.
[Edited on 24-9-2008 by Ephoton]
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Klute
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Refluxing sodium ethoxide and ethyl acetate will get you ethyl acetoacetate... Not a recommended solvent. I woul duse toluene and large excess of
MeOH. Even better, I would use NaOEt in the first place. Unless this is for some kind of Ar-X --> Ar-OMe swap?
Maybe making Mg(OCH3)2 from Mg metal and anhydrous MeOH, and then performing a metathesis with NaOH (insoluble Mg(OH)2 should drive the equilibrium
far to right)? Just an idea.
EDIT: Ephoton, IIRC Unionised posted a good method for extracting vanillin from vanilla extarct in the Raspberry Ketone thread, check it out. But I'm
sure if youlook enough you cna find synthetic vanilla flavouring composed of pur vanillin... And vanillin is the kind of chemical that a company that
doesn't normally sell to individuals will feel confortable selling...
[Edited on 24-9-2008 by Klute]
\"You can battle with a demon, you can embrace a demon; what the hell can you do with a fucking spiritual computer?\"
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kclo4
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| Quote: | Originally posted by not_important
| Quote: | Originally posted by kclo4
Can Propionaldehyde be produced by dehydrogenating N-Propyl alcohol over Copper catalyst much like how formaldehyde or acetaldehyde is produced?
...
Dang, I thought my reagents for organic synthesis book would help me out more then it does  |
Yes, although you get some condensation products too. If not adding air/O2, which is tricky to control, the conversion is incomplete; you'll want to
fractionate the product and recycle the n-propanol.
Pre-WW2 books are the best bet for this sort of method, pre-Depression a even better bet. |
All right, that is cool.
Do you have any reference for this? patents, etc?
I've been looking but I guess my searching skills are a tad poor.
Actually, for what I am doing and for what I have, can KMnO4 oxidize N-propanol to Propionaldehyde? KMnO4 always goes to the carboxlic acid doesn't
it? so I'd need a dichromite, which I hear as only about a 37% yield.
Yeah.. My Reagants for Organic Synthesis book is 1967.
[Edited on 24-9-2008 by kclo4]
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DJF90
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Not sure about the permanganate, but you'd dichromAte. I'm sure its just a typo though
Supposedly (according to an article on rhodium), Silica gel supported Jones reagent can be used to oxidise alcohols to aldehydes in fairly high yeilds
and doesnt allow any of the chromium compounds to leach out into your reactant (using DCM as a solvent). Here's the link:
http://designer-drugs.com/pte/12.162.180.114/dcd/chemistry/a...
Edit: Although on more careful reading, "except oxidation of primary alcohols to aldhydes, produce excellent results"
[Edited on 25-9-2008 by DJF90]
[Edited on 25-9-2008 by DJF90]
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sonogashira
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| Quote: | Originally posted by kclo4
All right, that is cool.
Do you have any reference for this? patents, etc?
I've been looking but I guess my searching skills are a tad poor.
Actually, for what I am doing and for what I have, can KMnO4 oxidize N-propanol to Propionaldehyde? KMnO4 always goes to the carboxlic acid doesn't
it? so I'd need a dichromite, which I hear as only about a 37% yield.
Yeah.. My Reagants for Organic Synthesis book is 1967.
[Edited on 24-9-2008 by kclo4] |
You can use dichromate in solvent-free conditions (see attached paper, in djvu format). I suggest you download Larock's Comprehensive Organic
Transformations from the References section. It might make your searching a little easier
Attachment: Solvent Free Oxidation of Alcohols to Aldehydes with Potassium Dichromate.djvu (170kB)
This file has been downloaded 856 times
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not_important
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| Quote: | Originally posted by chemrox
Hey not_, why is this so?
"Pre-WW2 books are the best bet for this sort of method, pre-Depression a even better bet. "
Any particular books in mind? |
The laboratory supply houses really expanded their lines of organics and unusual inorganics starting in the mid-1930s and especially after WW-II. As
a result most researchers just purchased most of the simpler reagents instead of making them; lab methods textbooks dropped those synthesis as a
result.
No particular book, I don't remember which books I've seen that in and most of my books are boxed and warehoused.
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Panache
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separating funnel with long stem
I noticed in one of Klutes pictures a sep funnel that after the bulb had a long tube section before the tap. What are these sep funnels and what are
they good for?
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not_important
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It can make separation easier. First, the narrow tube gives good visibility of the boundary. Second, in some cases the tube can help break up blobs
of one liquid in the other; it can even help speed up the separation of emulsions a bit. Third, when being used as an addition funnel, it gets the
bulb away from the crowded flask top; this was more common back before ground glass joints were common.
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starman
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Also they are handy for introducing additions to the bottom of rxn miture eg. ethanol introduction in ether synthesis.
Available from an ebay supplier in your neck of the woods if interested Panache.
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Klute
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Funny, because I have nearly always seen these kind of seperating funnels, and wondered what the point was of having an inverted-pear shape one, as
the seperation can be less precise/easy. I find the ones I have very practical to remove those last drops hanging around. Some somewhat viscous
solutions can cling to sides though, a good rubbing/shaking is then required to get them off, otherwise they fall off when the top layer is withdrawn
and the surface ring "pulls" them off.
\"You can battle with a demon, you can embrace a demon; what the hell can you do with a fucking spiritual computer?\"
-Alice Parr
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vulture
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| Quote: |
You can not literally "swap alkyl chains on alkoxides" but you can do an normal proton exchange to get the same result. |
As a sidenote, with 3-methoxythiophenes it's possible to do this using NaHSO4 and the corresponding alcohol or thiol. I don't know if it's generally
applicable to aromatics though, because it involves addition of a proton in the 2-position of thiophene.
[Edited on 27-9-2008 by vulture]
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texaspete
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desiccant
Which of the following is a stronger desiccant than powdered ammonium nitrate: copper sulfate, magnesium sulfate, calcium chloride, or sodium
hydroxide. Are there any other desiccants that will keep ammonium nitrate dry and are readily available?
Thanks!
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kclo4
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texaspete, I would think any of those mentioned would keep ammonium nitrate dry or would dry it. Magnesium Sulfate, Calcium Chloride, and the others
are all good desiccants from what I know.
-----------------------------------------------------------------------------
I've been trying to make chlorophenol lately via NaOH and an excess P-dichlorobenzene in methanol + a small amount of sulfur, since I thought the
sulfur might work as some sort of catalyst. I believe I have succeeded in making approximately 20grams of chlorophenol, but I need a way to test if it
is Hydroquinone because I fear that might be a significant side reaction. I doubt it but I'm not to sure if 4-chlorophenol would more willingly
replace its chlorine for a hydroxyl group more easily then P-dichlorobenzene would.
I was thinking of getting enough water to dissolve all of my product, as if it were Hydroquinone, and then what would be left would be chlorophenol.
However, I fear I would lose a decent amount of chlorophenol this way, if most of the product was chlorophenol.
A test for hydroquinone would tell me if i even needed to worry about it, but I seem to be unable to find a method to test for it.
It has a phenolic smell at least. 
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Ephoton
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that sounds excellent kclo4 so many tried to convert the halide on
thouse toilet lollies.
my self to test for hydroquinone I would try percipitating gold with it.
phenol will not do this from my experiance.
(the phenol I used was 4methoxy phenol)
were as hydroquinone will leave either a red or violet percipitate (or collodial
solution if only small amounts of gold is used.)
I would love to try this either the chlorophenol or the hydroquinone would make
me say goodbye to a supplier
[Edited on 28-9-2008 by Ephoton]
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raiden
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Does anybody have any info regarding sesamol to piperonal/safrole?
Cheers.
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not_important
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Adding strong aqueous NaOH to the cooled reaction mix, then distilling off the MeOH, cooling to 30-40 C, and filtering will separate unreacted
dichlorobenzene. Saturating the filtrate with CO2, or dropping the pH to around 6, and chilling should precipitate most of any p-chlorophenol out,
leaving hydroquinone in solution. Note that alkaline solutions of hydroquinone are easily oxidised by air.
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kclo4
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| Quote: | Originally posted by raiden
Does anybody have any info regarding sesamol to piperonal/safrole?
Cheers. |
no clue, but I do know of some other ways to Piperonal/safrole if you're interested.
Perhaps oxidize the OH with oxone into a ketone, if thats even possible?
____________________________________________
err, my solution of "chlorophenol" has crystals in it, and more form when it gets colder, but it only increases a very very slight amount. Perhaps I
have it to acidic with HCl? Does anyone have a solubility chart for 4-Chlorophenol? I've been looking but I have been unable to find anything on it.
Not_Important, that is almost exactly what I did, except for my pH is probably a lot lower - would this explain my crystallization problem?
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Ephoton
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why bother going to md when mmd -2 is better and stronger anyway.
what about if you used the gold solution to reduce the hydroquinone to
quinone then used an organic solvent to extract both the chlorophenol and
the quinone. then use a base in water to turn the phenol into a salt leaving the
quinone in the organic solvent.
the gold will percipitate all you need to do is the normal disolve then clean of
oxidizing agent to get it ready to clean the chlorophenol again.
you would probably loose very little gold each time you did this too so it would
be very very recyclable.
crystals hmmm hydroquinone from water makes thin needles if that helps.
[Edited on 28-9-2008 by Ephoton]
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kclo4
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| Quote: | Originally posted by Ephoton
why bother going to md when mmd -2 is better and stronger anyway.
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What do you mean by md and mmd -2?
| Quote: |
what about if you used the gold solution to reduce the hydroquinone to
quinone then used an organic solvent to extract both the chlorophenol and
the quinone.
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I don't have gold, and its pretty expensive
| Quote: |
then use a base in water to turn the phenol into a salt leaving the
quinone in the organic solvent.
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I do like this idea however! Quinone could probably be produced another way with out gold and also with out destroying the chlorophenol.
| Quote: |
crystals hmmm hydroquinone from water makes thin needles if that helps.
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But do you know if chlorophenol does also?
I know phenol crystals are thin needles also.
Thanks for the idea!
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Nicodem
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| Quote: | Originally posted by kclo4
I've been trying to make chlorophenol lately via NaOH and an excess P-dichlorobenzene in methanol + a small amount of sulfur, since I thought the
sulfur might work as some sort of catalyst. I believe I have succeeded in making approximately 20grams of chlorophenol, but I need a way to test if it
is Hydroquinone because I fear that might be a significant side reaction. I doubt it but I'm not to sure if 4-chlorophenol would more willingly
replace its chlorine for a hydroxyl group more easily then P-dichlorobenzene would. |
Obviously there can be no reaction between p-dichlorobenzene and NaOH in methanol unless you heat to >200°C which requires an autoclave. Such a
benzyne mediated reaction would however give you a mixture of 3- and 4-chloroanisole as well as 1,2-, 1,3- and 1,4-dimethoxybenzene (and a bunch of
minor side products including the toxic chlorophenolic crap). If you ever make any 4-chlorophenol or other chlorophenols even in trace amounts, you
will immediately know as it is has annoyingly insidious smell that sticks on you and your clothes for months. It is also quite toxic!
Panache: Avoid abusing this thread for your "jokes".
Ephoton: Reply in line of the question and do not diverge the topic.
…there is a human touch of the cultist “believer” in every theorist that he must struggle against as being
unworthy of the scientist. Some of the greatest men of science have publicly repudiated a theory which earlier they hotly defended. In this lies their
scientific temper, not in the scientific defense of the theory. - Weston La Barre (Ghost Dance, 1972)
Read the The ScienceMadness Guidelines!
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starman
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| Quote: | Originally posted by raiden
Does anybody have any info regarding sesamol to piperonal/safrole?
Cheers. |
Your serious? Phenolic group to unsaturated allyl group.Well some of the members may be knowledgable
enough to come up with that in a home lab,although the robustness of the MD grouping to survive would be suspect.
I think you are probably more interested in the ketone derivative,try wetdreams,they have an entire forum dedicated to the subject.You may also want
to research penalties for listed pecursors in your region.
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kclo4
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Nicodem, your right. I had mistaken some weird solution of "stuff" that formed for chlorophenol. I wasn't to sure what was happening, but Sodium
Chloride did precipitate and that's why i wanted to test for things. Thanks for letting me know! 
Penalties for precursors?
Do you have a reliable source for that sort of information regarding people in the US?
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starman
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Penalties for precursors?
Do you have a reliable source for that sort of information regarding people in the US?
The US...no.
My part of the world .... Possession of a small quantity of safrole "without lawful excuse"
(= assumed guilty of a crime regadless of legitimate explanation) punishable by up to 5 years jail and/or $25 000 fine.
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