Author Topic: Easy OTC benzaldehyde? (Read 804 times)

fresh1 · « **Reply #20 on:** March 13, 2012, 04:00:06 AM »

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Each to their own, personally I find it instructive to see how successive generations (not picking anyone - just observing) solve, or attempt, to solve the same raft of problems. I often wonder, just how much different the world would be and what outlandish results would exist, if older folks just allowed people to reinvent the wheel periodically.

good call matey

thank fuck curiousity is still free

Tsathoggua · « **Reply #21 on:** March 14, 2012, 01:24:26 AM »

And that the govt. don't shoot people for it...yet.

no1uno · « **Reply #22 on:** March 15, 2012, 03:56:14 AM »

What you'd need, presuming it were to work, would be something like a reflux column on a soxhlet-type arrangement, with the BnH/BnO mixture condensing and dripping into a cup (rather than a thimble) containing a saturated bisulphite solution. The adduct would form (it would take way too much experimentation for my liking to work out what sort of time frame and what percentage would form the adduct in the appropriate time frame) and then the excess BnH would overflow the cup and run back into the refluxing mixture.

Problems I can see immediately include the limited space - given only a smallish cup could be used otherwise too much BnH would be held in it and not reacting with KMnO4, while the limits on the volume of the saturated sulphite solution would limit the amount of adduct that could be recovered. There is also the expansion that is going to take place when the adduct is formed. Then there is the possibility that stirring would be required in order to increase yields of adduct, so that would require a stirbar & access for a stirrer plate.

It ain't going to be easy and I would strongly suspect that other oxidations would be a lot less complex (and probably give better overall yields in less time), especially those starting from BnOH/BnOBz which is kind of easy to source. Another problem is that due to Methcathinone KMNO4 isn't the easiest thing to source in any quantity anymore (neither is toluene in some areas).

Assyl Fartrate · « **Reply #23 on:** March 15, 2012, 05:29:15 PM »

That's unfortunate KMnO4 and toluene are hard to find OTC anymore. Have not poked around in a US hardware store in nearly ten years now...

Did some serious time (the reason for a new moniker and long absence). Experimentation is over for this guy. Just trying to dig up interesting ideas and toss them out for the dogs to tear apart... (admittedly this was a weak one and poorly thought through) been playing the role of volunteer researcher/literature comber. Take it as you will. Thanks again for useful feedback. Ego plays no role in these postings, just a quest for the truth and a desire to help make the drug war unenforceable. Shake and bake has caused a number of states to shut down their meth task forces and abandon all meth investigations, because the cost of cleaning up so many labs was prohibitive. Disgusting and lame as it is, the more we move in the direction of highly simple syntheses, the more police resources are subjected to a real world DDoS attack, and the more cover all of you have to do whatever you want.

BzOH is really easier to find now than toluene? If so there really is zero reason to try to make this crazy idea work...

If toluene is still available, the paper lugh posted with the hypochlorite oxidation of toluene (steam distilling benzaldehyde as it's formed) seems to be flat out the best way to go about this. As with most things here, yields don't have to be great as the product is always very valuable.

Wizard X · « **Reply #24 on:** March 15, 2012, 11:50:10 PM »

Quote from: Assyl Fartrate on March 15, 2012, 05:29:15 PM

If toluene is still available, the paper lugh posted with the hypochlorite oxidation of toluene (steam distilling benzaldehyde as it's formed) seems to be flat out the best way to go about this. As with most things here, yields don't have to be great as the product is always very valuable.

Ph-CH3 + X2 => Ph-CHX2 => Ph-CHO

X2 = Cl2 or Br2

Ph-CH3 + Br2 => Ph-CHBr2 => Ph-CHO

p-BROMOBENZALDEHYDE http://www.orgsyn.org/orgsyn/pdfs/CV2P0089.pdf
o-PHTHALALDEHYDE http://www.orgsyn.org/orgsyn/pdfs/CV4P0807.pdf

Assyl Fartrate · « **Reply #25 on:** March 16, 2012, 01:54:58 AM »

Not really practical unless you have a good fumehood... benzyl halides are very nasty. A respirator and "airtight" goggles won't do shit when you got those fumes around, you'll wish you'd just torn out your eyes, deep fried and ate them.

Of course, though, if you have a good fumehood, this is a great way of going about it.

Here's something that bares mentioning with an obligatory self-directed "duh": using a Soxhlet instead of a reflux column for this, to address the pressure problem mentioned by lugh... but the problem still remains, what Vesp mentioned - water is produced by the oxidation, the oxidizers generally have to be delivered in aqueous solution, and that's going to have the bisulfite dissolving and falling into the RB.

Expanding on nu1uno's idea... perhaps there could be two refluxes happening simultaneously? Instead of a cup, have that refluxing, the bisulfite adduct is not going to go up the column, but toluene will so it could be steam distilled back into the reaction vessel...

Ha... this is not seeming so simple anymore. The image that comes to mind is one from old cartoon mad scientists, with a room full of endless mazes of bubbling flasks, columns, and tubes full of colorful fluids...

fresh1 · « **Reply #26 on:** April 08, 2012, 08:03:28 AM »

I'm surprised sedit hasnt weighed in here...has anyone here looked around other forums?

Almost everything discussed here has also been discussed on SM in a 20 page sticky

http://www.sciencemadness.org/talk/viewthread.php?tid=2223

sorry to go off topic but what is the protocol of re-posting data found one one forum into another forum?

Clearly its done, but is it a respectful thing to do?

They say plagiarism is the greatest form of flattery

Assyl Fartrate · « **Reply #27 on:** June 16, 2012, 02:07:26 PM »

Haven't read through that entire thread. 20 pages is a lot - don't have the time to dig through that much. Care to provide a link directly to where the discussion on a similar idea begins?

Assyl does not plagiarize... to do so is immature and inhibits progress by stifling further research (due to a lack of references being given). Particularly pointless under an anonymous moniker.

It's natural for some of us to think of the same ideas simultaneously and independently - many major discoveries are credited not to those who came up with the idea first, but rather to those who could refine and publish before everyone else.

atara · « **Reply #28 on:** June 16, 2012, 09:16:31 PM »

http://www.sciencedirect.com/science/article/pii/S0926860X04009652

Perhaps you can simply use Vitamin B12 instead? Cobalt tetraphenylporphyrin is very similar, merely synthetic and cheap to make in bulk. The catalyst loading in the paper is really, really low, though... I don't know what they were trying to do.

Electro´S · « **Reply #29 on:** June 17, 2012, 12:34:20 AM »

Selective Oxidation of Benzylic and Allylic Alcohols with NaOCl/Silica Gel System

What you think about this route?

Preparation of NaOCl/SiO2 as an Oxidizing Agent
To a round bottomed flask (200 ml) was added 20 g silica
gel (60-200 mesh) and a solution of 6% NaOCl (50 ml). The
suspension was mixed thoroughly and then dried by freeze
dryer apparatus. The reagent at this point is a homogeneous,
free flowing white powder, which is not sensitive to moisture
and light. Storage under an inert dry atmosphere and in a
brown bottle appears to greatly increase the shelf time of
reagent. Prolonged heating under vacuum produced a powder
of no or low utility for the reaction. Potentiometric
measurement of NaOCl content in the reagent was found to be
17 mmol NaOCl per 10 g reagent.
Oxidation of 4-Chlorobenzyl Alcohol as a Typical
Procedure
NaOCl/SiO2 (17 mmol, 10 g), 4-chlorobenzyl alcohol (10
Alinezhad et al.
289
mmol, 1.44 g) and DMSO (2.25 mol%) were added to 25 ml
of CH2Cl2. The mixture was refluxed for 5 min and progress
of the reaction was monitored by GC. After completion of the
reaction, the mixture was filtered and the solvent was removed
under reduced pressure. The crude 4-chlorobenzaldehyde was
purified using column chromatography (1.39 g, 98 %).

If the amount of NaOCl/SiO2 would be readjusted to make this route more volume efficient, this would be a good selective and OTC route to Benzaldehyde. Any suggest at this point???

Can any one explain me wath means "freeze
dryer apparatus"?. Sorry I´m not chemist and English is not my native lenguaje.
Thanks!!!

lugh · « **Reply #30 on:** June 17, 2012, 02:40:43 AM »

Quote from: atara on June 16, 2012, 09:16:31 PM

http://www.sciencedirect.com/science/article/pii/S0926860X04009652

Perhaps you can simply use Vitamin B12 instead? Cobalt tetraphenylporphyrin is very similar, merely synthetic and cheap to make in bulk. The catalyst loading in the paper is really, really low, though... I don't know what they were trying to do.

That's a rather interesting abstract describing a widely used catalyst for a novel green chemical oxidation process

Cyanocobalamin does contain cobalt as part of it's very complex chemical structure, but cobalt tetraphenylporphyrin is a polymer supported catalyst system that has not much else in common with it structurally

There's definitely too much information freely available on the internet about this catalyst to post here, but one such article about a closely related catalyst system is attached

Assyl Fartrate · « **Reply #31 on:** June 17, 2012, 03:38:26 AM »

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agreed... But it's NOT that fresh wants to 'plagiarize' No, it's all about sharing data amongst the bees and wasps

Sorry, grossly misinterpreted your post... thought you meant this whole thread was plagiarism!

Don't see anything wrong with pasting here, so long as it's a readable format and the source is given.

akcom · « **Reply #32 on:** June 17, 2012, 01:55:13 PM »

Quote from: atara on June 16, 2012, 09:16:31 PM

http://www.sciencedirect.com/science/article/pii/S0926860X04009652

Perhaps you can simply use Vitamin B12 instead? Cobalt tetraphenylporphyrin is very similar, merely synthetic and cheap to make in bulk. The catalyst loading in the paper is really, really low, though... I don't know what they were trying to do.

You'd probably be better off just using cobalt acetate like they do in the paper. B12, while containing cobalt in the same oxidation state as Co-TPP, lacks the same reactivity due to the electron count on cobalt.

lugh · « **Reply #33 on:** June 17, 2012, 04:25:51 PM »

Quote from: akcom on June 17, 2012, 01:55:13 PM

Quote from: atara on June 16, 2012, 09:16:31 PM
http://www.sciencedirect.com/science/article/pii/S0926860X04009652

Perhaps you can simply use Vitamin B12 instead? Cobalt tetraphenylporphyrin is very similar, merely synthetic and cheap to make in bulk. The catalyst loading in the paper is really, really low, though... I don't know what they were trying to do.
You'd probably be better off just using cobalt acetate like they do in the paper. B12, while containing cobalt in the same oxidation state as Co-TPP, lacks the same reactivity due to the electron count on cobalt.

That Science Direct abstract doesn't use cobalt acetate, but of course it has been used as a catalyst for doing the same process as described in the attached patent

Other articles using alternative catalysts are attached

akcom · « **Reply #34 on:** June 19, 2012, 06:26:35 AM »

lugh,
While it does not mention copper acetate in the abstract, the article itself compares the efficiency of the cu-porphyrin to Cu(OAc)2. The porphyrin has better selectivity, but not by much. The only important difference in the yield (8.9% for Cu-TPP and 2.9% for Cu(OAc)2). Realistically though, we're already talking about a very low yielding process.

Is benzyl alcohol really that hard for bees to obtain? A recent tetrehedron letters paper used t-butyl nitrite (easily synthesized from tert butyl alcohol) to oxidize BzOH to benzaldehyde in very impressive yields with no work up required.

atara · « **Reply #35 on:** July 06, 2012, 11:33:25 PM »

reckless: 4-methoxy donates electron density and makes the ring a lot more reactive. I don't think it'll work otherwise.

akcom: Benzyl alcohol isn't hard to obtain, but neither is benzaldehyde itself. I think the point of a route from toluene is for something large-scale?

Quote

no work up required.

Haha, that's a good one.

akcom · « **Reply #36 on:** July 07, 2012, 03:02:13 PM »

Should have been more clear. The work up simply involved evaporation as the side product is tert butyl alcohol. If you wanted to be cheap you could distill and use the tbutyl-oh to regenerate your nitrite. I see what you're saying though. When it comes to scale toluene is probably the way to go

Author Topic: Easy OTC benzaldehyde? (Read 804 times)

fresh1

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Tsathoggua

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no1uno

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Assyl Fartrate

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Wizard X

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Assyl Fartrate

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fresh1

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Assyl Fartrate

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atara

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Electro´S

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lugh

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Assyl Fartrate

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akcom

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lugh

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akcom

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atara

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akcom

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