toluene --> benzaldehyde

Did another run with neogravitron method. Used a 25 ltr plastic bucket & fixed a drill with metal stirer over the top. Sealed with a garbage bag. Yield ~ 400mls.

benzaldehyde success not easy but high yeild

Benzaldehyde synthesis via phenylalanine

Don't know why this quoted reaction would work since we're starting out with an acid (Phenylalanine)......solo

Persulfate oxidations

Well bees....

SWIM recently tried that US patent where they speak of oxidazing toluenes with Na2S2O8 with MeOH as a co-colvent and Cu/Fe catalyst.....

Unfortunately, SWIM has no methanol so he tried to sbstitute it for a) AcOH b) DMF c) IPA.

With AcOH, the yield was like 10%, the chief product being benzyl acetate That is, as soon as BzOH is produced, it is esterified under the rxn conditions and can no longer oxidize.

With DMF ...... err...... when you mix DMF with persulfate solution, it heats up spontaneously within 10 mins and violently decomposes

Same thing happened with IPA - but SWIM decided to try it again adding IPA separately in portions. Yielded only 30%.

It turned out that ALL of the oxidant disappeared from the rxn immediately after addition (tested with acidic KBr) although with MeOH it's supposed to last for 2 hrs more.

EtOH seems not to bee an option since upon contact with persulfate it produces acetaldehyde at once.


That is, all in all, it looks promising (i.e., don't mind the NH4/Na difference, i assure you), but methanol is the only solv't that could work.

It;s heavily controlled in Russia and no matter how hard a bee tries, he can't get his hands on any. But i assume you guys don't have that problem, do you?

Then i encourage you to give it a try. It's going to work.




Antoncho

[Edited on 22-10-2005 by Antoncho]

How about ethanol instead of methanol? That should be considerably easier to acquire in Russia (distillation from Vodka?).
Interesting thing is that in germany you can buy all the benzaldehyde you'd ever want from chemical suppliers. It's non- regulated and non- scheduled here. Are things so different in Russia?



[Edited on 22-10-2005 by garage chemist]

I'd say it's not that strange, those alcohols are NOT very similar in their manner of beehaviour towards oxidants: MeOH is much more resistant (being much more "electron-hungry".

Anyway, the main point is - there's nothing to bee _talking_ about here - we won't know until someone tries this. The rest of the dicussion is useless crap

If anyone wishes, i can post a write-up of SWIM's own experience, so that may bee of help.

I have tried this procedure as well but only got a very low yeild. Probably kept the persulfate solution (MeOH/H2O) too long before using..

SC Wack, don't be discouraged, don't be frustrated. Your efforts are truly noted (and I am not just speaking for myself).
You don't have the 'bibliomaster' title for no reason'.
Although this may be in French, I'll always know, if I am ever to run into difficulties of making benzaldehyde from toluene (via bromination), the article you scanned will be one to check; presumably the same for many others here.
Although of course I'd first produce it from benzoylalcohol and K2Cr2O7
Seriously, keep up the good work. Not everyone may appreciate/need it, but still, it doesn't mean it's a waste of time.
The sheer broadness of this forum is what I like about it. Any language, any noteworthy procedure is worth diamonds as long as it works, regardless the language or intention.

Furthermore, I am sure some people are willing to translate if that is required.

Many thanks, and regards.

styrene -> benzaldehyde

Nice syntheses on orgsyn.org.

I think benzahdehyde can be prepared by many ways.

phenylcarbinol (benzyl alcohol)
--->
bezaldehyde

chlorination of toluene to benzalchloride
C6H5CHCl2
--->
bezaldehyde

or maybe chloromethanol is prepared by methanol and HCl
and the chloromethanol is threathed with Clorox bleach and NaOH solution to bezaldehyde.

[Edited on 15-4-2006 by Madandcrazy]

Quote:

Originally posted by Madandcrazy Nice syntheses on orgsyn.org. I think benzahdehyde can be prepared by many ways. phenylcarbinol (benzyl alcohol) ---> bezaldehyde chlorination of toluene to benzalchloride C6H5CHCl2 ---> bezaldehyde or maybe chloromethanol is prepared by methanol and HCl and the chloromethanol is threathed with Clorox bleach and NaOH solution to bezaldehyde. [Edited on 15-4-2006 by Madandcrazy]

Any other Route

Cinnamon oil to benzaldehyde update.

Hi peeps, been off the forum a good while but its good to be back .

I’ve significantly improved the original batch method I posted last year, what follows is my latest method.

This approach uses the same setup as the last steam distillation variation graphically depicted in in this thread.

Basically, the items used were:
hot plate, pressure cooker steam generator & associated tubing, etc
3L 3-neck RBF & mantle
vigreux column, right angle bend & still head
condenser
Vacuum pump & glassware for purfying the final product & recycling unreacted cinnamaldehyde.

chemicals: 2 litres tap water, lecithin, cinnamon oil, NaOH

Essentially, a large reaction vessel and a means of steam & vacuum distilling are all the equipment really required.


Begin by setting up all equipment, add 2 L water & ~1.5g lecithin.
The first variation is to use OTC sodium hydroxide instead of sodium carbonate, simply add the alkali to adjust the pH within the range of 12-13, only small amounts are required.

The second variation is to slowly drip in the cinnamon oil during the course of the reaction, the benzaldehyde being steam distilled as it forms. Begin the addition once the pH adjusted solution has heated to boling temperature and the steam is passing though the solution.

The third variation is to stop the cinnamon oil addition after 5 min, then check the distillate. If benzaldehyde is clearly distilling over, then continue with the addition.
A crude test is to simply taste the steam distillate as it drips into the receiving vessel, if it burns your tongue off, then you're doing well. If it tastes sweet, then significant quantities of cinnamon are being carried over. Should this not change after a short while, then double check the pH !

Provided that the pH is correct and the cinnamaldehyde content is high (70%+) then benzaldehyde laden distillate should start collecting almost immediately after the addition has begun.
However, if it is not, wait for the benzadehyde to start collecting, THEN continue with the addition. This prevents unnecessary amounts of cinnamaldehyde being steam distilled at the start of the process, which is a serious problem with the old batch mode reaction.

Note that by slowly dripping the cinnamon oil instead of adding it all at once to the reaction mix, single run conversion is increased by 20-30%.

Ensure the rate of cinnamon oil drip rate is approximately equivalent to the quantity of oil being steam distilled, thus maintaining high dilution in the reaction mixture.

After 300 to 500 ml of cinnamon oil had been added, the drip rate is stopped and the steam distillation continued until all the aldehyde has been steam distilled from the reaction mix. If using less than 2L of water, then adjust proportionally to maintain the same dilution. At this point, dump the mix and replace with clean pH adusted water with at least ~1.5g lecithin.
This step removes tar and other junk that slows down the reaction and reduces benzaldehyde production. Significantly reduced tar formation will also result from periodically carrying out this step (very imporant if high yields are desired).
Also note that with this method, the pH tends to slowly drop over time during the course of the steam distillation, so check the pH every couple hours, and top up with NaOH if and when required. Its preferable to simply add small amounts concentrated NaOH solution when topping up, using a dropper makes the alkali addition much simpler since NaOH pellets will rapidly collect moisture and stick to the sides of the reaction vessel.

Efficiency is further improved if the steam distillate (after oil separation) is also extracted with DCM, though this isn't absolutely necessary.

Once the the product oil is pooled, vacuum distillation will remove the benzaldehyde - no need to vacuum distill the recycle cinnamon aldehyde, just drip it into the steam distillation vessel, just as with the cinnamon oil feed. Expect the quantity of unreacted cinnamon aldehyde to be circa 25%, but if the reaction mix was kept clean during the process then it may be considerably less. The benzaldehyde distillate is clear, & much purer than the original solvent extraction method that doesn't employ the steam distillation. Give the batch solvent extraction a rest folks, use the steam distillation variation if producing benzaldehyde from cinnamon oil!
Far, far less work.

Using the above approach, overall molar conversion to benzdehyde is at least 80%.

I’ve managed higher conversion efficiencies (~90%), but the reaction efficiency is subject to variation according to varying reaction conditions, i.e. feed rate, reaction mix volume (i.e. dilution), and the quantity of cinnamon oil fed to the reaction mix before changing the solution. >80% seems to be a realistic overall figure.

Also...
Remember to keep the reaction mix free of tar & cinnamon oil impurities as much as possible to give consistent high yields.

If dripping the aldehyde into the mixture isn't practical for any reason, you can periodically add the cinnamon oil in small batches, say 20-50 ml at a time to give good conversion, but expect a little more cinnamonaldehyde to distill over.

John, is benzaldehyde still legal in NZ? For long? In Queensland and WA its now on the same schedule together with such notables as lysergic acid and P2P. That is 15 years maximum for illegal possession of more than 0.1g! Presumably amateur experimentation is included. The list also includes such obviously drug related chemicals as chromic acid, alkali metals, and magnesium. Here were only allowed to dig ore, and you to tend sheep

[Edited on 23-7-2006 by len]

[Edited on 23-7-2006 by len]

Update on the running reaction:

After some hours I had to stop the steamdistillation for it got to late and I had to go to bed. The distillate which had come over - not very much - was waterclear with a nice clear blob on the bottom. But the distillation seemed to have slowed down over time and I got the impression that only a part of the cinnamaldehyde got converted into benzaldehyde and so I added some NaOH before restarting the steamdistillation this morning.
Much more distillate started to come over it is turbid, clear blobs at the bottom are slightly yellowish now.

So I ask myself: Does NaOH on the one side speed things up but on the other side produce a decent amount of sideproducts?
Or did I just fuck up something and if - what? Did the NaOH react with the frigging cooking oil I had to add to reduce foaming? Darn!

Suggestions for other anti-foaming agents? Paraffine/Stearine maybe? Or just some margarine or butter?

Addon: The yellow discoloration and the turbidity come most probably from mist (caused by the foaming) driven over. For I cannot fix this in this run now I decided to ignore the issue, to drive the shit forcibly over and to do another steamdistillation on the product. Anything else would be endless.
In the next run I will obmit the splashhead and instead insert some glasswool into the Claisen which hopefully suffices as demister.

Addon2: Well sometimes I should listen to what I tell others and whats written in the basic literature
A second batch is in steamdistillation and it runs quick and easy just from a 2l Erlenmeyer/Claisen/Liebig combo. No splashhead, no oil, no glasswool. Ehem. Steamdistillation, as short way as possible as large diameter as possible. I guess a retort would be perfect. Or something like these irish whiskey stills.

[Edited on 2-8-2006 by Organikum]

whats happened to all the pictures?

Quote:

Originally posted by herbalextractions whats happened to all the pictures?

It can be done trough "ketonization" with formic acid (which then becomes "aldehydation" ):
US4847424

Related patents:
US2053845
GB514452
GB382929 (uses Ca salts in a batch process)
GB190411747 (also Ca formates)
(there must be other related patents as well...)

I don`t know the correct conditions to the synthesis. A rapidly stirrred
mixture should give the intermediate formyl in
the solution with the carbon monoxide content in the air
and the hydrochloric acid. This should be adequate, when
this not work bubble CO gas through the solution.
Not enough infos are available within the synthesis of
benzene if the formyl is formed by bubbling gently 1 mol of
CO gas into the solution after the HCl is added, the correct
temperatures or how long the synthesis need to complete the process.
I suppose a additional possibility is when the mixture of benzene/aluminium chloride/copper(II)chloride is
stirred between 6 - 10 °C, CO gas (air need longer reaction
time) is bubble into the mixture and over one hour the HCl is
dropped with a funnel into the solution.

[Edited on 20-11-2006 by Mason_Grand_ANNdrews]

[Edited on 20-11-2006 by Mason_Grand_ANNdrews]

[Edited on 21-11-2006 by Mason_Grand_ANNdrews]

benzaldehyde from toluene

overoxidisation & aldehyd'ation?

It can be done trough "ketonization" with formic acid (which then becomes "aldehydation" ):
US4847424

This is perhaps the most important patent I have noticed upon this topic. It even describes in some detail the production of the required catalyst(s). In addition to which, it does, somewhat unusually provide a level of detail on the actual reaction sequence.

I assume such a simple reaction should in fact work as well with catchetol based carboxylic acids?

If so, it would appear that the most productive, if not the most elegant route, would in fact be to proceed to over-oxidise past the desired product, without even attempting to stop the reaction, and then to use formic acid (albeit in massive quantities) to 'aldehyde'ise' the product.

The only problem I have is the sheer volume of THF that would be required to perform these reactions at any volume. Surely there must be an alternative solvent?

problem solved 102 years ago

Tyvek may be the ticket