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bbartlog
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I would not expect potassium iodide to be very soluble in glacial acetic acid; in fact I'd expect it to be insoluble or nearly so. However if I
understand what you are trying to do correctly, you should be able to electrolyze a concentrated aqueous solution of potassium acetate and potassium
iodide and (possibly) obtain some methyliodide. This reaction should be mostly about the anions (well, and current density and concentrations and
probably anode composition) so potassium acetate rather than acetic acid should actually be an improvement due to the far greater dissociation. Though
I suppose I don't know what your experiment is really about...
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bbartlog
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Speaking of solubility questions: can anyone tell me whether anhydrous CuCl2 is slightly soluble in chloroform? I've observed a slight solubility of
the hydrate (CuCl2.2H2O) in the azeotrope (97% CHCl3, 3% H2O) (forms a colorless solution, which suggests something other than Cu++, e.g. HCuCl+ and
Cl- or ... something), but I can't find any reference data for chloroform in the places I usually look for solubility data. And I thought what I saw
might have been due to the presence of water.
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Hamilton
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easy one, or maybe not at home.
i have got braium sulfate and want to make barium nitrate ou chloride with it, since the solubility of barium sulfate is virtually 0 i don't know how
to let the Sr free from the SO4.
how would you do it?
thx
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Random
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I took some zinc from the battery, why doesn't it react with 9% vinegar?
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bbartlog
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| Quote: | | have got barium sulfate and want to make barium nitrate or chloride |
The electronegativities are such that simple metathesis is probably not going to do anything (barring access to rare reagents like cesium chloride),
barium being very low and sulfate (in the group electronegativity sense) very high on the scale. And it's not like you can distill out the product to
push things in the desired direction. Probably your best angle would be reduction to barium sulfide via heating with carbon, followed by leaching the
sulfide and reaction with nitric or hydrochloric acid, but I'm sure the carbothermic reduction requires and/or generates glowing hot temperatures.
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bbartlog
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| Quote: | | I took some zinc from the battery, why doesn't it react with 9% vinegar? |
It should, but slowly slowly. A strip of zinc metal will take days or even weeks to dissolve in dilute room temperature acetic acid. Use zinc powder
or heat up the reagents to speed things up.
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DJF90
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| Quote: | However if I understand what you are trying to do correctly, you should be able to electrolyze a concentrated aqueous solution of potassium acetate
and potassium iodide and (possibly) obtain some methyliodide.
...Though I suppose I don't know what your experiment is really about... |
Its a Kolbe-type electrolysis experiment, trapping the methyl radical with iodide to yield MeI. Theoretically very clever, but may be difficult in
practice. I'm not sure of the solubility of KI in acetic acid but I would expect CRC to tell you or at least give you a vague idea. However the methyl
radical is typically nucleophilic in behaviour, leading me to think that elemental Iodine would be preferable. I don't think this will work well
though because radical combination (2Me* => EtH) should be much quicker.
| Quote: |
The electronegativities are such that simple metathesis is probably not going to do anything.
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This has very little to do with it. You're not going to metathesise anything if you can't get it into solution first! Solid state may work but again
its difficult experimentally. The best route would be the one you post:
| Quote: |
Probably your best angle would be reduction to barium sulfide via heating with carbon, followed by leaching the sulfide and reaction with nitric or
hydrochloric acid, but I'm sure the carbothermic reduction requires and/or generates glowing hot temperatures.
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And yep, it is a high temp reaction. Please bear in mind that whilst Barium sulfate is pretty benign (owing to its negligable solubility), other
barium salts are pretty toxic. Be careful.
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un0me2
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Ok, I have a question - we've all (I'm presuming) seen the use of N-(Trifluoroacetyl)-amino acid chlorides/etc. used in Friedel-Crafts Acylation of
various phenols, alkoxyphenols, benzene, etc.
The reason for the Trifluoroacetyl Group is that it is easily removed (basic hydrolysis?) and reacts fairly easily and quickly with the amine
(especially if one uses the haloacetones - sounds like fun - to do so).
Now, the pKa of Trifluoroacetic acid (TFA) = ~0.00 & that of Trichloroacetic acid (TCA) is ~0.77, so they should be similar insofar as their
reactivity, I have also seen several papers where TCA has been used to protect the amino group of various compounds, being equally easily cleaved by
base as TFA.
So, having gone through all of that, is there any REAL reason why so many papers use TFA instead of TCA for the F-C Acylation of benzene or
alkoxyphenols? Could N-(Trichloroacetyl)-glycine for instance be used instead of the TFA counterpart in the F-C Acylation of 1,4-dimethoxybenzene? I'm
searching for it, but cannot find any references, although (given what is said in one paper I've requested) the relative cost of preparing the TCA
derivative is a LOT less than the preparation of the TFA derivative (so I'd be expecting industrial scale-up to use it if it worked).
quam temere in nosmet legem sancimus iniquam
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manimal
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I am curious: is dimethyl sulfide/sulfoxide/sulfone oxidizable to methanol+sulfate ion? The reason I ask is that I read a report in popular media of a
possible medical explanation for the death of an individual as in-situ oxidation of dmso to dimethyl sulfate.
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Formatik
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DMSO doesn't convert to dimethyl sulfate in the body, it does convert to the sulfone though ("MSM", which is also sold as a supplement). One person in
the world had a magical body that supposedly converted DMSO to dimethyl sulfate. DMSO is used even intravenously as a transporter in medicinal
formulations.
Sulfoxide oxidizes to sulfone with strong oxidants, like H2O2, organic peroxides, hydroperoxides. Acidic aq. Cl2 yields the sulfone and
methanesulfonyl chloride. Not even ozone (one of the most powerful oxidants there is) apparently oxidizes beyond sulfone. Have a look at this bulletin
on page 17: http://www.gaylordchemical.com/bulletins/Bulletin105B/index.... There seem to be a few papers in the net on the oxidation of sulfoxide with ozone.
And dimethyl sulfone is a very stable material, literature reports when it was heated with fuming nitric and fuming sulfuric acid nitrating mixture
for several hours, it did not decompose it!
I know myself also that if you store DMSO for a long time (several years), it becomes rancid (worthless medicinally, but still usable for some
chemical reactions) and takes on strong dimethyl sulfide odor. I don't recall if I read somewhere, if not some paraformaldehyde might also form in the
mix also.
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d010060002
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The strongest concentration of ammonia that is pure and easy to get was 10%. A lot of the recipes I'm looking at require a more concentrated form. Has
anyone concentrated ammonia with good results using an easy method (boiling, freezing at a reasonable temperature).
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sakshaug007
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| Quote: | However if I understand what you are trying to do correctly, you should be able to electrolyze a concentrated aqueous solution of potassium acetate
and potassium iodide and (possibly) obtain some methyliodide.
...Though I suppose I don't know what your experiment is really about...
Its a Kolbe-type electrolysis experiment, trapping the methyl radical with iodide to yield MeI. Theoretically very clever, but may be difficult in
practice. I'm not sure of the solubility of KI in acetic acid but I would expect CRC to tell you or at least give you a vague idea. However the methyl
radical is typically nucleophilic in behaviour, leading me to think that elemental Iodine would be preferable. I don't think this will work well
though because radical combination (2Me* => EtH) should be much quicker. |
This is exactly right, and the purpose of this experiment in which I seek is to determine the yield and perhaps refine the reaction conditions so as
to obtain a primary product of methyliodide versus the ethane Kolbe product. I've done some further research and it looks as though methanol as a
solvent using a smooth platinum anode is preferable and of course potassium or sodium acetate would be the better reagent as opposed to acetic acid
due to increased dissociation. My thoughts are to mix a saturated solution of potassium acetate and potassium iodide (in the proper molar ratios) in
methanol and then attempt electrolysis. I'm not sure about certain details such as stirring or heating the solution while electrolyzing, and also
whether the methyliodide would undergo anodic oxidation as well, any suggestions? Does anyone think this will work?
Thanks
[Edited on 10-8-2010 by sakshaug007]
[Edited on 10-8-2010 by sakshaug007]
"If everyone knew everything what would be the point?"
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Nicodem
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Quote: Originally posted by sakshaug007  | | This is exactly right, and the purpose of this experiment in which I seek is to determine the yield and perhaps refine the reaction conditions so as
to obtain a primary product of methyliodide versus the ethane Kolbe product. I've done some further research and it looks as though methanol as a
solvent using a smooth platinum anode is preferable and of course potassium or sodium acetate would be the better reagent as opposed to acetic acid
due to increased dissociation. My thoughts are to mix a saturated solution of potassium acetate and potassium iodide (in the proper molar ratios) in
methanol and then attempt electrolysis. I'm not sure about certain details such as stirring or heating the solution while electrolyzing, and also
whether the methyliodide would undergo anodic oxidation as well, any suggestions? Does anyone think this will work? |
Well, there will not be much acetate anion oxidation at the anode until all the iodide gets oxidized to the iodine (or iodate if you do not use a
membrane to separate from the cathode). Check their redox potentials! Of course, if an overvoltage of the iodide is achieved then some acetate will
start to get oxidized, but not under normal operating conditions. Anyway, once you have all the iodide oxidized to
I<sub>3</sub><sup>-</sup>, or more likely only when oxidized to I<sub>2</sub>, the acetate will start to oxidise
to methyl radicals and CO2. At this point methyl iodide could start forming by methyl radicals being oxidized by
I<sub>3</sub><sup>-</sup> and/or I<sub>2</sub>.
I don't know why you think methanol would be a good solvent for this. Check the C-H dissociation energy for methanol and methane. You might be
surprised that methyl radicals easily abstract hydrogens from many substances, especially the alpha-hydrogens of alcohols. Water is obviously an ideal
solvent for such an experiment. Triiodide is very soluble and iodine soluble enough in water.
The electrodes should be separated by a semipermeable membrane. If so, I don't think you should worry much about MeI reacting at the electrodes. In an
non-separated cell it could react at the cathode and being reduced to methane, but I doubt this happens that easily. Chances are it could also react
at the anode to form a iodoso compound, but I doubt. It could however succumb in the reaction with radicals, because iodine is easily abstracted from
alkyl iodides. but if a methyl radical abstracts iodine from methyl iodide, guess what it gives... However, there could be other radical species
involved, like the acetoxyl radical (which is short lived as it decomposes to methyl radical and CO2). Also, if the formation of MeI is faster than
its consumption in putative side reactions, once the aq. phase is saturated with MeI (and this happens fast) this will start depositing in its own
phase (where it is protected from the electrodes).
PS: You already asked about this in the previous short questions thred. Perhaps you should consider opening a dedicated thread given that you keep
bringing this up. Describe the problem and add all the pertaining references and link back to your question in this thread.
…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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sakshaug007
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| Quote: |
I don't know why you think methanol would be a good solvent for this. |
I don't want the H2O -> O2(g) + e- + H+(aq) reaction interfering at the anode.
I did already bring this up in an existing thread about iodomethane prep. http://www.sciencemadness.org/talk/viewthread.php?tid=12394&... but nobody provided any input!!!! I seem to be the only one interested in this
technique which makes me think its not gonna work.
As always thanks for being the only one to thoroughly answer my questions Nicodem.
[Edited on 11-8-2010 by sakshaug007]
"If everyone knew everything what would be the point?"
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solo
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Is there a study or does someone know, about this compound (N-methyl-1-phenyl-propan-2-amine) where the there exists a double bond between C1 and C2,
effects on the activity of the compound....since the compound is derived from alpha-methyl cinnamaldehyde...(perhaps i could have worded my inquiry
better), ...as i seem to recall a studies where the variables are changed with the amine group and the benzene ring but never noted any changes on
the variables of the alkyl chain..............solo
It's better to die on your feet, than live on your knees....Emiliano Zapata.
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Nicodem
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I suggest you to always check redox potentials, species concentrations (including their pKa and activity) and their electrode overpotentials before
worrying about such things. Besides, what makes you think methanol would not get oxidized at the anode? Already intuitively you should know that it is
more easily oxidized than H2O.
You wanted to start a discussion on electrochemistry in a thread dedicated to the classical MeI preparation and you gave no references whatsoever.
Obviously that was doomed to end there. Compile all the references you got on the topic and open a thread in the proper way. That is the only way to
open a fruitful discussion topic. Just posting fragments here and there, unsupported by any literature or experiments, is obviously not going to lead
anywhere.
| Quote: Originally posted by solo | | Is there a study or does someone know, about this compound (N-methyl-1-phenyl-propan-2-amine) where the there exists a double bond between C1 and C2,
effects on the activity of the compound....since the compound is derived from alpha-methyl cinnamaldehyde...(perhaps i could have worded my inquiry
better), ...as i seem to recall a studies where the variables are changed with the amine group and the benzene ring but never noted any changes on
the variables of the alkyl chain..............solo |
Methamphetamine with "a double bond between C1 and C2" is an enamine so it can not be subject to activity studies (assuming you mean biological
studies). How about starting to use IUPAC nomenclature? It is always so confusing to figure out what compound you are talking about. Alternatively
post the structure. The direct product of reductive amination of alpha-methylcinnamaldehyde is something else, like I already told you above, and
still you keep calling it that way. The enamine compound I assume you ask about is N-methyl-1-phenyl-2-aminopropene and is not something that can be
derived directly from alpha-methylcinnamaldehyde without a multistep process, so you can't go on calling it a compound derived from alpha-methyl
cinnamaldehyde. IUPAC has given us a nomenclature to be used, so use it.
…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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sakshaug007
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| Quote: | | Compile all the references you got on the topic and open a thread in the proper way. |
Sadly, nicodem, the only reference I have on this direct subject (i.e. alkyl halide synthesis using NON-Kolbe electrolysis) is written in
German, HENCE ALL OF MY QUESTIONS!! I have the reference attached if anybody would care to translate it for me, but until then the only other material
I have come across pertains to Kolbe electrolysis itself (radical dimerization). I simply expanded on this topic to apply it to the synthesis of alkyl
halides (methyliodide being a simple one) as they are not easy to obtain for at home experiments. I don't have halide acids, I don't have phosphorus,
and I don't have thionyl chloride. What I have are acetates/acetic acid and potassium iodide thats it. So please, bare with me or perhaps provide me
with some references on this exact area of research.
On the other note, I can't find standard electrode potentials for either methanol or acetate ion. Again, can you point me in the right direction?
Attachment: electrolytic production of CH3I.pdf (776kB)
This file has been downloaded 854 times
"If everyone knew everything what would be the point?"
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turd
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Well, there surely has been some interest in rigid amphetamine analogs, if that is the question.
Random list of links:
http://www.erowid.org/library/books_online/pihkal/pihkal056....
http://www.google.com/search?q=rigid+amphetamine
http://en.wikipedia.org/wiki/2-Aminotetralin
http://en.wikipedia.org/wiki/2-Aminoindane
http://en.wikipedia.org/wiki/EXP-561
I can see why - if it's rigid there's no question which conformer resides in the receptor. (?)
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manimal
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| Quote: Originally posted by Formatik | DMSO doesn't convert to dimethyl sulfate in the body, it does convert to the sulfone though ("MSM", which is also sold as a supplement). One person in
the world had a magical body that supposedly converted DMSO to dimethyl sulfate. DMSO is used even intravenously as a transporter in medicinal
formulations.
Sulfoxide oxidizes to sulfone with strong oxidants, like H2O2, organic peroxides, hydroperoxides. Acidic aq. Cl2 yields the sulfone and
methanesulfonyl chloride. Not even ozone (one of the most powerful oxidants there is) apparently oxidizes beyond sulfone. Have a look at this bulletin
on page 17: http://www.gaylordchemical.com/bulletins/Bulletin105B/index.... There seem to be a few papers in the net on the oxidation of sulfoxide with ozone.
And dimethyl sulfone is a very stable material, literature reports when it was heated with fuming nitric and fuming sulfuric acid nitrating mixture
for several hours, it did not decompose it!
I know myself also that if you store DMSO for a long time (several years), it becomes rancid (worthless medicinally, but still usable for some
chemical reactions) and takes on strong dimethyl sulfide odor. I don't recall if I read somewhere, if not some paraformaldehyde might also form in the
mix also. |
That was pretty much my analysis. Here's the article I was refering to: http://discovermagazine.com/1995/apr/analysisofatoxic493
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Formula409
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Has anyone had any experience cleaning up the formaldehyde you can buy OTC which has a coloured dye in it (normally for camping toilets). I'm thinking
just adding a bit of activated charcoal should be sufficient.
Formula409.
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bbartlog
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| Quote: | | I have the reference attached if anybody would care to translate it for me |
Not going to translate the whole thing, but some points I gleaned:
- they claim great difficulty in condensing the methyl iodide due to it being diluted and (I guess) entrained by the ethane and CO2 which are produced
in greater quantity. So for their analysis they lead the gas into an alcoholic solution of dimethylaniline, which apparently reacts with the
methyliodide. You likely wouldn't want to take this route even if you had dimethylaniline handy, but it sounds like you'll have to worry about
cooling. Or condensing. Obtaining the methyliodide as a separate phase may not be practical. Given that it boils at 42C I'm a little surprised at the
claimed difficulty, but I guess it's very volatile.
- in general they appear to have been interested in elucidating the mechanism rather than finding some way of maximizing production, which makes their
paper a bit tangential to your purpose.
- they used a cell with a clay membrane, platinum anode, and lead or copper cathode.
- for anode solution they used both potassium acetate and elemental iodine (65g potassium acetate, 160cc water, 10g iodine), and sodium acetate plus
potassium iodide (40g and 10g plus 100cc water). One trial was at 2.5 amps for 6 hours, the other at 1.6 amps for 12 hours. In both cases it sounds
like they obtained less than a gram of iodine (as methyl iodide) on analysis.
- unfortunately, no information is given on the anode dimensions or the applied voltage.
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mewrox99
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Is dry calcium carbide flammable
2 CaC2 + 5 O2 = 2 CaO + 4 CO2
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stygian
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Will Na2C2 hydrolyse in alcohols?
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12332123
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Is it possible to synthesise alkoxides by electrolysis of either halides or hydroxides in alcohol?
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Nicodem
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The pKa of most alcohols is rougly 15-16 while that of acetylene is about 25. That pKa values are for water, but what is importance is the difference,
and ten magnitudes is one hell of a difference. BTW, it took me exactly seven seconds of googling (seriously, I counted!).
If you use an alkali salts for the electrolyte, then yes. There are also a few other electrolytes that reduce the protons of the alcohol instead of
their cationic part, but I won't bother searching given you don't bother specifying which alcohol and alkoxide of what you are interested in. For
example, if the metal cation is easily reducible (e.g. Cu2+, Pb2+...) then it will simply get reduced and deposit on the cathode instead of forming an
alkoxide. Of course, the electrodes must be separated by a semi-permeable membrane and the alcohol must be anhydrous. You might find it a problem to
isolate the metal alkoxide from the used electrolyte though. A long enough electrolysis to assure complete oxidation of the original anion of the
electrolyte could remove most of it, but that does not sound that easy unless the anion has a very low redox potential. Though for simple alcohols
like ethanol, propanol, butanol, etc. and their alkali alkoxides there are a few considerably simpler and faster methods to prepare them (UTFSE for
more info).
…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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