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Hilski
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I distilled the aldehyde from the reaction with the brownish Mn alum, and the yields were actually a bit higher than normal, say 10 -12%. But, yields
of the red tar were also quite a bit higher than normal, and not as much toluene was recovered during the post reaction work up. I also tried to
"over regenerate" the mixture again, and I wasn't very successful as getting the brownish colored solution. There were some brown 'swirls' mixed in
with the red solution, but not nearly as pronounced as before. I don't know what the difference is now. There may be too much organic material left
in the cell, which is reducing any of the brown IV valence oxidizer as soon as it is formed.
I think I'm going to focus on making a functional setup to produce the brown persulfate oxidizer for the time being. I would like to see how much the
yields improve in proportion to any extra effort needed to use this oxidizer as opposed to the red alum.
\"They that can give up essential liberty
to obtain a little temporary safety
deserve neither liberty nor safety. \"
- Benjamin Franklin
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jimmyboy
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has anyone actually tried the dry distillation of calcium formate + calcium benzoate - seems it would be cheaper and easier to go this direction -
formic acid is easy to get as well as benzoic acid... i wonder what the yields are..
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womble
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Just mix the two (both food additives aren't they?) and heat?
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chemrox
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acetone cyanohydrin
did anyone mention acetone cyanohydrin ala Vogels?
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not_important
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| Quote: | Originally posted by jimmyboy
has anyone actually tried the dry distillation of calcium formate + calcium benzoate - seems it would be cheaper and easier to go this direction -
formic acid is easy to get as well as benzoic acid... i wonder what the yields are.. |
Usually not that good, the aldehyde group gets trashed too easily; better when making aromatic ketones. The method was used before the reduction of
the acid chloride and the various ways using oxidation of a methyl group came into use.
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Organikum
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Well I made benzene and propiophenone this way, benzene with very good and propiophenone with good (>50%) yields.
But not from the calcium salts (for benzene it was tried but gave unsatisfactory yields). Sodium salts for benzene and ferric salts for propiophenone
IIRC.
The trick in these dry distillations is the heat transfer, a problem I solved by adding coarse steelwool to the mixture.
I liked these experiments very much, last not least for the dry distillations actually worked for me.
Didnt think about making b-dehyde this way as I had no source of formic acid at this time, but hey! I have seen it for sale cheap & OTC lately in
this wonderful Drogerie & Chemie shop I discovered by accident, next to the ether and stuff.
Thanks for bringing this up!
/ORG
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not_important
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Benzene from benzoic acid is an aromatic decarboxylation, while the aromatic and other ketones usually are a condensation to a beta-keto acid,
followed by decarboxylation of that. Different reactions going on. For the ketones calcium, barium, manganese, and occasionally iron, salts were the
choices to go with. The alternative is to pass the free acids over a heated oxide, thorium being the most common but manganese and calcium being used
as well.
The aldehydes are yet another reaction, and as the resulting aldehyde is fairly reactive the yields tend to be lower than for the ketones. From some
reading I did years ago, you can tune the conditions to optimise yields, in some cases becoming respectable, but a rather tedious process to get
there. But when the acids are cheap and easy to get, it's worth trying.
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S.C. Wack
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The older literature does say that the yields for benzaldehyde are bad from formate/benzoate. Inert gas flow or at least flushing out oxygen, and
experiments with different cations would be a good idea if one wanted to try it.
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Organikum
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I referred to the benzene synthesis mainly for the similarity of the technique as I posted this in the benzene thread. Solvent can and coarse
steelwool and this.
The synthesis of P2P from phenylacetic acid and acetic acid via the lead salts by dry distillation is a classic, yields are told to be >70% when
mild vacuum is applied and the reaction is done on a decent scale.
Propiophenone from benzoic acid and propionic acid via the iron salts (black magnetic iron powder as used as concrete pigment works, no reduced iron
needed) works well too, >50% yield without vacuum and on a comparable small scale (800ml solvent can as reactor).
I have little doubt that b-dehyde can be made this way in good yields. I dont think that oxygen is a big issue, but if one thinks so then adding some
sodium bicarb at the bottom of the reactor should take nicely care of this, the CO2 evolved upon heating should drive out the oxygen.
Oxydation in the condensor is probably a bigger issue - I would recommend to use a short copper condensor and to prevent air circulation in the
condensor.
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nightflight
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| Quote: | Originally posted by technologist
May be an Stupid Question?
Can I make it using Benzene & some aldehyde or ....May be any other route leaving Toluene.
_________________________________
Visit my Blog - http://profmaster.blogspot.com |
Yes there´re, also not very common yet, making use of the DMSO and protonating it to a kation which will form a substitutionproduct with an 1° or
2° alcohol in a swern like oxidation.
Starting compund for benzaldehyde would be benzylalcohol, DMSO can be activated by acetic anhydrid, oxalchlorid (swern-oxidation) or
dicyclohexylcarbodiimid by -20°C at least and addition of a water-scavenger.
Anyone wants to try?
The mosdt simple way may be Benzylacohol ->MnO2 +CH2Cl/Me(OH) to benzaldehyde and Mn(OH)
[Edited on 15-2-2007 by nightflight]
[Edited on 15-2-2007 by nightflight]
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nightflight
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Experimental: Betonite (catlitter) and KMnO4 were ground in equal amounts until purple turned to light violet and all was ground to dust and a mol
ratio of 0.1 Toulene and 0,4 KMnO2 was measured out.
It was then put into a pyrex beaker and irradiated for 25min. on 1/2 power, until a gleaming of the mixture was noticed after 7min. and heating was
stopped.
It was all dried out and all the tolly evapped.
[Edited on 12-3-2007 by nightflight]
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Coldfinger
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any references?
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roamingnome
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the references could bare your name... if aldehyde is what you think happened and wanted...
permanganate at an oxidation state of 7+
the clay would be absorbing water and microwaves....
did you smell any cherries...? at any time.... it may have flown out as it was made...
benzoic acid..?
shoot, you could mix anything.and something will happen.
the problem is finding out what happened.
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nightflight
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| Quote: | Originally posted by Kinetic
A quick search for toluene to benzaldehyde gave me - unsurprisingly - a lot of hits. The extract from the article below is a solvent-free oxidation
with potassium permanganate supported on montmorillonite, but does not suffer from the particularly large amounts of oxidant often required for such
transformations. Still, it isn't a procedure you'd use on a large scale. The following is exemplified for indane -> indanone, with the same
procedure giving benzaldehyde in 60% yield in 18h when applied to toluene. Taken from Tetrahedron Letters, 43, 5165-5167
(2002):
2.1. Oxidation of indan under classical conditions
Potassium permanganate (3.16 g, 20 mmol) and montmorillonite K10 (6 g) were ground together in a mortar until a fine homogeneous powder was obtained.
Indan (0.24 g, 2 mmol) was added to this KMnO4/K10 mixture (4.5 g, 9.9 mmol) in a 25 mL round bottomed flask and mixed magnetically at room
temperature until TLC (eluent: hexane–ethyl acetate) analysis indicated a completed reaction (20 h). The residue was then washed with CH2Cl2 (2×20
mL). After filtration and removal of the solvent, the crude product was chromatographed on silica gel (eluent: hexane–ethyl acetate) to give
purified product (0.22 g, 1.7 mmol, 85%)
Using microwave irradiation, as below, gave benzaldehyde in 54% yield in 12 minutes:
2.3. Oxidation of tetralin under microwave irradiation
In a 25 mL Teflon beaker, tetralin (0.26 g, 2 mmol) was added to KMnO4/K10 (4.5 g, 9.9 mmol). After 3 min of mechanical stirring, the mixture was
irradiated at medium power for 25 min. At the end of exposure to microwave irradiation, the mixture was cooled to room temperature and eluted with
CH2Cl2 (2×20 mL). After filtration and solvent removal the crude product was chromatographed on silica gel (eluent: hexane–ethyl acetate) to give
purified product (0.24 g, 1.7 mmol, 82%).
Some other references for the oxidation of toluene to benzaldehyde are:
Synthetic Communications, 29(7), 1177-1182 (1999), using sodium bromate and cerium dioxide;
Tetrahedron Letters, 28(10), 1067-1068 (1987), using ceric methanesulfonate (91% yield);
DE168291, in which 'air and water' is used;
DE127388, using nickel oxide (edit: duh, of course this is the same as posted by S. C. Wack above);
DE101221 (which appears to be the one cited by Orgy as DE102221), DE107722 and Journal of the Chemical Society, 91, 263 (1907), using manganese dioxide and sulfuric acid;
DE158609, using cerium dioxide and sulfuric acid;
and DE175295, using 'manganese dioxide sulfate'.
That's pretty much it for the easy to get reagents. I haven't read any of the papers (partly as I don't speak German) so I'll keep my fingers crossed
that they are of use.
[Edited on 17-1-2005 by Kinetic] |
this reference.
No, no smell of benzaldehyd or benzoic, just tolly and cat-litter smell.
I did a search on converting phenylalanine to benzaldehyd, which I heard of anywhere, but didn´t find anything, could sopmeone please help out? It´s
so sad if I had to buy it instead of generating it myself.
[Edited on 13-3-2007 by nightflight]
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guy
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Just a question. How do the Cu and Fe catalysts work? What is the mechanism?
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Filemon
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| Quote: | Originally posted by S.C. Wack
There are of course a jillion ways to do things...they all have some disadvantage or other...even in the dark |
Does it mean that the benzal bromide forms peroxides with the H2O? Is the benzal bromide been accustomed to room temperature?
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Sauron
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In the Oxidation of ethanol thread, the use of nickel peroxide (aka nickel oxide hydroxide) arose, which can be catalytic or used stochiometrically or
in excess. The reagent is in either case generated in situ from nickel salt and common 5% Na hypochlorite bleach, and is a black insoiluble solid.
A review I dug up mentions early on the use of nickel peroxide to oxidize toluene to benzaldehyde so I thought I would call this to you attention.
Apologies all around if this has been brought up in this thread before.
If not, anyone want the review?
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Polverone
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It appears that S.C. posted an old German patent early in this thread that mentions the use of this nickel compound or a closely related one, but I
don't read German. I would appreciate having the review that you have.
PGP Key and corresponding e-mail address
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Sauron
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Your wish is my commend.
The review cites German Patent 127,388 of 1900, which may be same as @S.C. posted. This appears to be first use of this reagent. Toluene is oxidized
to benzaldehyde and benzoic acid.
Reference 11 from this review concerns among other things the use of nichel peroxide to selectively oxidize benzyl alcohol to benzaldehyde under mild
conditions.
I have already obtained this in full text as I finally mastered the trick of getting ACS journals to give up their pdf's. Want this one as well?
[Edited on 5-4-2007 by Sauron]
Attachment: cr60296a004[1].pdf (1.6MB)
This file has been downloaded 2207 times
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S.C. Wack
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The patent says little, as far as I can tell. NiO(OH) is made from a nickel salt + hypochlorite or alkali/halogen; and 300 kg toluene + 150 kg "dry"
NiO(OH) are heated to 100C for 5-6 hours, the reduced nickel cpd. is filtered, and the mystery yield of benzaldehyde isolated by bisulfite or steam
distillation. CoO(OH) also works.
There would be little surprise if the isolated yields are in the single digits.
I suspect that the other review mentioned is an older Chem Rev from vol. 38 (1946). BTW it and the above Ni oxide review are part of my 65 selected Chemical Reviews available via ftp.
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Sauron
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True enough, that 1900 German patent failed to mention yield.
Not so however the J.Org.Chem. article cited in the CR review as Ref. 11 and hereby attached.
Benzyl alcohol is smoothly and very selectively oxidized by only a slight excess (1.1-1.2 eq based on available oxygen) in 3 hours at 50 C in a yield
of >90% and with only a slight recovery of unreacted benzyl alcohol or benzoic acid. This reaction is carried out in benzene as solvent. Other
solvents such as ether or pet.ether as possible.
Unfortunately for the acetaldehyde thread, oxidation of ethanol in organic solvent gives very poor results, while oxidation in aq. alkaline soln gives
high yields of acetic acid.
I would like to also call your attention to another J.Org.Chem article concerning the use of same reagent on a catalytic basis (2.5 mol%) rather than
in stoichiometric amounts. This is instructive by comparison and might perhaps be extended to the topical problem of this thread. Such application at
this time is purely speculative.
J.M.Grill, J.W.Ogle, S.A. Miller, J.Org.Chem. 71, 9291 (2006)
which I will be happy to post if anyone wants to see it.
[Edited on 5-4-2007 by Sauron]
Attachment: jo01052a026[1].pdf (567kB)
This file has been downloaded 2206 times
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tupence_hapeny
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Here is one which I have yet to see here, it uses trichloroisocyanuric acid to chlorinate toluene (using catalytic quantities of benzoyl peroxide) in
44% yield, but without photo/etc.
http://pubs.acs.org/cgi-bin/abstract.cgi/joceah/1970/35/i03/...
The resultant benzyl chloride apparently is mixed only with unreacted toluene (as unlike other experiments there are no mention of side-products).
This appeals, as it would appear that most people can get hold of goodly amounts of tri/dichloroisocyanuric acid (or its sodium salt). Benzoyl
peroxide is available (try the catalyst/hardener for automotive putty/bog - generally ~50%wv).
Of rather more importance, here is a relatively recent article on the two-phase chlorination of toluene, using (sorry my bad, I originally wrote
trichloroethylene, thinking of something else entirely ) chloroform/water and salt
- which proceeds in ~90% conversion and almost total selectivity. The beauty of this procedure is that there is no need for hydrochloric acid (or
exotic chlorinating agents) the Chlorine is generated in situ from the electrolysis of the upper aqueous layer, and apparently passes through the
interface between the layers quite well.
[Edited on 21-4-2007 by tupence_hapeny]
[Edited on 21-4-2007 by tupence_hapeny]
Attachment: Electrochemical Chlorination Toluene (2-Phase), Electrochemica Acta (2005).pdf (108kB)
This file has been downloaded 4412 times
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Sauron
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Both look interesting.
44% yield is not so impressive, but might be useful for the chemically challenged who cannot obtain TCT.
TCCA does seem to be ubiquitous.
TCT/DMF and benzyl alcohol ->benzyl chloride 100%.
Anyone making BzCl is going to need a good hood.
Hmmm. You forgot to mention a wee detail. Your 44% chlorination of toluene w/TCCA ONLY RUNS IN CCl4. In absence of carbon tetrachloride, TCCA with
either of the two catalysts (FeCl2 or H2SO4) produced ONLY mixed o- and p-chlorotoluenes in modest yields 45-66% and no benzyl chloride.
That takes it right out of the OTC category and dumps it in the UNOBTAINIUM file. CCl4 is no longer available in most countried OTC and is restricted
(by special license only) for academic or industrial users, just like chloroform and Tric, Perc, ethylene dichloride etc. Is this not the case where
you are? It's the bloody environmentalist assholes at work.
Waste of time!
Some nice references in there, re TCCA iand THF -> GBL. Well maybe not so nice. 19% yld, ugh.
[Edited on 21-4-2007 by Sauron]
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tupence_hapeny
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| Quote: | Hmmm. You forgot to mention a wee detail. Your 44% chlorination of toluene w/TCCA ONLY RUNS IN CCl4. In absence of carbon tetrachloride, TCCA with
either of the two catalysts (FeCl2 or H2SO4) produced ONLY mixed o- and p-chlorotoluenes in modest yields 45-66% and no benzyl chloride.
That takes it right out of the OTC category and dumps it in the UNOBTAINIUM file. CCl4 is no longer available in most countried OTC and is restricted
(by special license only) for academic or industrial users, just like chloroform and Tric, Perc, ethylene dichloride etc. Is this not the case where
you are? It's the bloody environmentalist assholes at work. |
I noticed that only after you pointed it out, however, I assume another solvent could be utilised to make this work? For instance, how does chloroform
cope with benzoyl peroxide? Alternatively, wouldn't trichloroethylene be just as effective? Particularly if, as would appear likely, it was converted
to the tetrachlor in situ? (I ask this last question as I have access to gallons of trichlor for stuff all (electrical cleaning solvent) and would
really like to know if it would be able to be used instead of chloroform in the electrolytic chlorination procedure).
Personally, I would probably convert the benzyl chloride directly to benzyl alcohol (rxn with water), and then oxidize that to benzaldehyde. The two
step approach would appear preferable, given the consistent low yields experienced by all trying to establish 1 step approaches. Anyhow, this is my
opinion, if someone wants to direct me to a 80+% conversion & yield, 1 step approach, I would obviously prefer that - then again, so would
industry
PS the catalyst for the reaction is Benzoyl peroxide, I do not suggest using the H2SO4 or FeCL2, however - we have a problem with the solvent only.
BTW, this would appear to, at least, partially validate your proposal that TCCA could be useful for the preparation of acyl chlorides, especially
given that this route is essentially the same as another which uses the same system, albeit with sulfuryl chloride (but still toluene & benzoyl
peroxide) to prepare benzyl chloride. This would suggest that TCCA is a fairly useful chlorinating agent, of the same category as sulfuryl chloride,
thionyl chloride, etc.
I have attached an article, detailing the uses of 2,4,6-Trichloro-1,3,5-triazine (aka 2,4,6-trichloroisocyanuric acid, cyanuric chloride is the cyclic
version of cyanuric acid (altered as there was ambiguity - not a good thing on this board)).
ENJOY
[Edited on 21-4-2007 by tupence_hapeny]
[Edited on 21-4-2007 by tupence_hapeny]
Attachment: Recent Applications of TCICA in Organic Synthesis (2006) 62 Tetrahedron 9507–9522.pdf (418kB)
This file has been downloaded 16514 times
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Sauron
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Both chloroform and trichloroethane are just as verboten as carbon tet here and I fgather in most places in the world.
DCM has a much lower bp and cannot achieve the required reaction temps
In short maybe obe can find a replacement solvent, and maybe not. At the minimum, this turns a literature prep into a research project.
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