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Author: Subject: toluene --> benzaldehyde
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[*] posted on 29-5-2013 at 15:03


In the p-toluenesulfonic acid thread, it was mentioned that thiol and other once common impurities are very rarely found in commercial toluene now a days, do to a change in the indrustrial manufacturing. In older texts and patents these impurities where a big concern, but are much less common now, IIRC.



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[*] posted on 30-5-2013 at 09:00


Benzaldehydes from Propenylbenzenes and Cinnamic Acids

has anyone ever tried this method?
http://www.erowid.org/archive/rhodium/chemistry/benzaldehyde...
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[*] posted on 30-5-2013 at 09:21


Quote: Originally posted by Waffles SS  
Benzaldehydes from Propenylbenzenes and Cinnamic Acids

has anyone ever tried this method?
http://www.erowid.org/archive/rhodium/chemistry/benzaldehyde...


Have a look at the scale they are carrying the reaction out on and then calculate scaling it up to say 10g.
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[*] posted on 5-6-2013 at 21:15



Quote:

Benzaldehyde By dry distillation of a mixture of calcium benzoate and calcium formate


http://www.expertsmind.com/learning/benzaldehyde-assignment-...


Somebody has more information about this method?

Quote:


Calcium benzoate when pyrolyzed at 500 c produced
about equal amounts of benzene and diphenyl ketone


Mechanism of ketonic decarboxylation. Pyrolysis of calcium decanoate
Ronald A. Hites , K. BiemannJ. Am. Chem. Soc., 1972, 94 (16), pp 5772–5777
DOI: 10.1021/ja00771a039
Publication Date: August 1972
http://pubs.acs.org/doi/abs/10.1021/ja00771a039?journalCode=...




[Edited on 6-6-2013 by Waffles SS]
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[*] posted on 8-6-2013 at 02:04


I have read before on these decomposition methods, calcium salts may be used but I remember that iron ones may give out even better results.

I made iron benzoate and distilled a small amount of it with calcium acetate which should have produced acetophenone. It did produce something with a strong smell but I never had enough of it to check what it is.

Dry distillation of acetate with formate should produce aldehyde, but it would contain quite a few impurities and yields would be low. I'm up for the results if someone wants to perform this though.
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[*] posted on 13-6-2013 at 22:13


Quote:

1-Naphthaldehyde has been prepared from calcium α-naphthoate by distillation with calcium formate

Lugli, Gazz. chim. ital., 11, 394 (1881)

Banzaldehyde From Calcium Benzoate + Calcium formate

[Edited on 14-6-2013 by Waffles SS]
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[*] posted on 3-7-2013 at 08:11


Hi guys,
One more question, I don't have any NaHSO3 so I guess I would use distillation. From what I read here, benzaldehyde gets destroyed when you distill it but it does work.

What product do you get when you distill?
I'm guessing water (from the sulfuric acid) and toluene comes over at first and then toluene and benzaldehyde and then mostly benzaldehyde as the temperature reaches 178.1 °C (1 atm).

Is that correct?
Perhaps I can reduce the pressure but the problem is leaks.
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[*] posted on 22-7-2013 at 10:07


You know what, they should give us a means for liking each others posts, just like facebook lol



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[*] posted on 28-8-2013 at 03:35


you know what, after looking at cyclonight's post I took out my dripper funnel and I got it to drip at a rate of 3 drops per second and then 40 minutes latter it was dripping at 13 drops per second and then 15 minutes latter it wasnt dripping at all.

Is it such that dripper funnels behave this way or is mine a reject ?




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[*] posted on 29-8-2013 at 00:03


I cant get my dropper funnel to keep a constant rate, last night it was one drop every 3 seconds and then like an hour later it was around 1 drop every 13 seconds. Is this common with dropper funnels ?



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[*] posted on 5-9-2013 at 08:05


Quote: Originally posted by questions  
I cant get my dropper funnel to keep a constant rate, last night it was one drop every 3 seconds and then like an hour later it was around 1 drop every 13 seconds. Is this common with dropper funnels ?


Yes, I had this problem. If you haven't already done so, remove the teflon/pp stop cock from the funnel, and using a razor blade, carefully cut a narrow V into the hole edge so that you get a more variable and controllable drip rate. Obviously this isn't possible if you're using a glass stop cock, but most are plastic these days.
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[*] posted on 20-10-2013 at 15:01


I apologize for stupid question, but what comes when one reacts styrene with KMnO4? I cannot translate the image linked below into common name?

http://www.organicchemistry.com/wp-content/uploads/BPOCchapt...

http://www.organicchemistry.com/oxidation-reduction-of-organ...
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[*] posted on 1-6-2014 at 16:02


Has anyone tried this method? The FC methylation of benzene is rather unnecessary considering toluene is easily available. They did switch brominating reagents from the start of the article, but I've seen several proven methods of producing benzyl bromide, so if you were to do that and then react it with hydrogen peroxide and ethanol it would probably work. They didn't include any sort of mechanism in the paper but I would guess that the water in the hydrogen peroxide solution hydrolyzes the benzyl bromide followed by oxidation of the alcohol using the hydrogen peroxide.



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[*] posted on 31-7-2014 at 14:39


I am attempting the electrolytic manganese-ammonium sulfate oxidation as posted by Cycloknight on page 3 of this thread, but I am noticing no change in color of the cell mixture. I am running at 1/12 of his scale and putting through 2 amps at 5 volts. The cell temperature, maintained by resistive heating, is 63 C. I am using platinum coated titanium electrodes. I have been running the cell for about 45 minutes, yet it remains stubbornly tan.

Are my electrodes messing stuff up (Pt overvoltage for oxygen 0.77 V, Pb overvoltage 0.81 V)? Can anyone else comment on this reaction?

I've replaced my anode with a graphite one, and I haven't noticed any difference yet.

I've switched back to platinum after my graphite anode was corroding (approx. 30 minutes). I've noticed a slight red-violet color appearing after checking it just now. I will leave the cell running overnight.


[Edited on 1-8-2014 by Cheddite Cheese]




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[*] posted on 1-8-2014 at 15:52


The cell seems mostly oxidized (based on color, and it is plausible for the amount of amp-hours passed), and the current has dropped to 0.3 amps. I will soon add toluene.

Never mind, it's still not done. I made an electrode out of solder (60% tin, 40% lead), and it works MUCH better than Pt.

Do NOT use a platinum anode for this experiment. It is not very effective.


[Edited on 2-8-2014 by Cheddite Cheese]




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[*] posted on 13-9-2014 at 07:07


for making benzaldehyde from toluene,we could try this indirect route
first make phenylnitromethane

http://www.orgsyn.org/demo.aspx?prep=cv2p0512

at the bottom of the page,under "discussions",alternative methods are given(benzyl cyanide is not easy to get and hard to work with).the first one heats toluene with dilute nitric acid in a closed tube.this method was discussed by AndersHoveland in a previous thread-http://www.sciencemadness.org/talk/viewthread.php?tid=23542

("But the reaction with toluene is more complicated. A little known fact is that nitrogen dioxide actually reacts at room temperature (20 °C) with toluene to form phenylnitromethane, where a nitro goup is actually added to the methyl group of toluene.

"Phenylnitromethane has been prepared by the nitration of toluene with dilute nitric acid in a sealed tube."
Konowalow, Ber. 28, 1860 (1895).
(the sealed tube probably implies heating)

At higher temperatures, addition of two nitro groups on the same carbon predominates. "nitration of toluene with nitrogen dioxide at a temperature between 20 °C to 95 °C yields a mixture of phenylnitromethane and phenyldinitromethane")


the second method is to react benzenediazonium chloride with nitromethane.this reaction is easy,efficient and nitromethane is OTC.

after phenylnitromethane is made,we can perform the "nef" reaction to convert nitro to aldehyde.the yield is 70%

more about nef reaction

https://www.erowid.org/archive/rhodium/chemistry/nef.html

https://www.erowid.org/archive/rhodium/chemistry/nef.peroxid...

http://bitnest.ca/Rhodium/pdf/nef.reaction.review.2004.pdf





[Edited on 13-9-2014 by CuReUS]
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[*] posted on 11-10-2014 at 03:41
Oxidation of benzyl chloride to benzaldehyde


I have found some research conducted by Republic of China, they claim they found an efficient and convenient method for the transformation of benzyl halides to coresponding carbonyl compounds. Example they presented is oxidation of benzyl chloride to benzaldehyde.. They claim they found that benzyl chloride could be oxidized to benzaldehyde by sodium nitrate (or potassium) in the presence of some catalyst at reflux....

I am interested if someone from this forum conducted this particular or similiar experiment and what are results.. ?

BTW sry for my English i am well aware i have more than few grammar mistakes..
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[*] posted on 11-10-2014 at 05:01


I don’t see much of an advantage of using nitrates in the presence of "some catalyst" when already DMSO works well for the oxidation (DOI: 10.1021/ja01524a080). There are plenty of reports in the literature of oxidations of benzyl halides with various nitrate salts, but the yields are rarely comparably as good as the Kornblum or related reactions (like the oxidation with nitronates, amine N-oxides and hexamine). Unless the catalyst is something trivial and the yields are significantly better.
Quote: Originally posted by Akira990  
I am interested if someone from this forum conducted this particular or similar experiment and what are results.. ?

You appear to believe we are mind readers? "Republic of China" is not an author or scientific journal. I don't think anybody cares much about the grammar, but this is after all a science forum and therefore you are expected to use references. Please read the forum guidelines for more information.




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[*] posted on 11-10-2014 at 05:20


i was wrong about the yield
its actually 94%:o (benzaldehyde oxime----->benzaldehyde)
benzaldehyde oxime will be the intermediate formed when phenylnitromethane is reduced via Fe/HCl according to the nef reaction
the only difficulty is to make phenylnitromethane using the method described by anders hoveland in my previous post

could someone get that piece of literature?
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[*] posted on 11-10-2014 at 14:53


@Nicodem

My mistake.. catalyst used are acetic acid (AcOH) and polyethylene glycol 600 (PEG-600)

Yields depends of oxidant used NaNO2 (sodium nitrite) 87%, KNO3 (potassium nitrate) 89%, NaNO3 (sodium nitrate) 91%..

They also conducted experiment without catalyst(s) to show how much yields change..

About references, Ministry of Education of the Republic of China and Natural Science Foundation of Jiangsu province...

I can present more details if needed that concern experiment they conducted...
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[*] posted on 14-10-2014 at 04:15


Here is the original document... Are this yields possible or not, they claim they got 90%... ?

Attachment: 54760-89674-1-PB.pdf (114kB)
This file has been downloaded 860 times

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[*] posted on 4-12-2014 at 09:55
Hope this can assist.


Hello,

I constructed and ran such a cell some years ago (about 6 liters total volume of all reagents) and after much the same results as I read now here regarding low yields, it finally occurred to me that what was occurring was that the toluene was simply evaporating out of the top of the open cell before it was able to be reacted.

Upon sealing the cell and using a conventional condenser to manage pressure build up I was able to achieve the claimed yields.

If you look at the illustration in the old patent where they used several hundred KG of reagents, you can see that the 'tardis' or I guess even phallic shaped steel (I assume) reactor they used was a closed unit with a condensing pipe running from the top back down into the main body of the reactor.

Hope this helps everyone with their frustrations.

P.S. Computer power supplies connected in parallel are a cheap source of lots of amps if you can scrounge old discarded PC's which is very easily done as you may be aware.

I had about 10 or so CPU power supplies (about 3 plugged into each household circuit) in parallel at up to 35 amps a piece... I did not need any heating in the cell :) I did need thick, thick copper braid !

This regenerates fast.

Lead is easily obtained on the cheap from your metal recyclers, melted by a propane flame and poured onto ceramic tiles to create beautiful sheets of almost pure lead that you can cut up with tin snips or whatever for your anode etc.

Overhead stirring using a medium speed/high torque motor is a must and a bitch to seal. Failing going pro and purchasing a proper lab quality nipple setup, you can use the brass/s steel combo bearing out of the bottom of a food blender or similar appliance and use silicone or epoxy to jig it up.

Such a setup requires constant replacement of silicone or ptfe based lubricant or the sulfuric will eat the SS. You couple/join the SS center originally from the blender to a glass stirring shaft and paddle with a plastic "shaft coupler" from a hobby/model shop (looks like a hollow cylinder standing on its short end with two horizontal plastic hex head screws on the side that grasp the two vertical shafts) as anything else will work loose in my experience.

I am sure others will think of better ways, this was just what occurred to and worked for me.
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[*] posted on 27-3-2015 at 15:49


Hi Folks, I tried to oxidize some toluene today in the vapor phase. I started with around 300ml, after two hours run the liquid got a yellow tint. I will boil it with some NaOH tomorrow to see if there is any benzoic acid. The setup is as in the acetaldehyde thread the catalyst was copper wire.
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[*] posted on 28-3-2015 at 08:31


Hi there,

Instead of addig NaOH I poured some water into the flask and azeotroped out the organic phase.
The water in the pot smelled strongly of benzoic acid.
The water phase in the trap smelled benzaldehyde
The upper phase you would not guess... toluene.

So you can make benzaldehyde by this method I yet to do some more experiments to say how much.

But how would you extract 1-2w% benzaldehyde from toluene contaminated with benzoic acid?

With the bisulphite method or simply by using a column? Thanks!

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[*] posted on 28-3-2015 at 08:50


Jimmy you are really pioneering many uses for your catalytic device!

I am currently in the middle of an aldehyde synthesis which uses bisulphite for its isolation. I'll post the results soon (I hope).




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