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Author: Subject: toluene --> benzaldehyde
simba
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[*] posted on 21-9-2011 at 08:51


Quote: Originally posted by questions  
Hey guys

I was told by someone that the cannizaro reaction only happens when the solution is alkalai and this is when the ph is 14 plus. I'm confused because i'm thinking about a reaction that happens between the ph range of 12 to 13 to make benzaldehyde from cinnamon aldehyde as previously disscussed
.
Thus does the cannizaro reaction only happen at a ph of at least 14 or can it even happen at a range of say between 12 and 13 with aldehydes?


This ain't true and if you had read the topic you would know that...there was a guy in this topic who did the reaction using sodium bicarbonate as base, so no way this was a ph 14.
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[*] posted on 3-10-2011 at 22:08


I believe substituting the mno2 with mno4 would provide a better yield? I don't know that much chemistry however but its just an opinion. considering that its a liquid phase oxidation and that mno4 has more oxidization capability I think it could be of some use. the only negative "things" I can imagine going wrong is (1) a small scale side-reaction producing
mno2 and h20? which I dont think will really harm the yields at all and (2) the other being safety issues, but you already have knowledge concerning oxidizers so I dont think safety problems are an issue

=neat experiment, and nice thread




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[*] posted on 4-10-2011 at 14:11


Quote: Originally posted by cyphazard  
I believe substituting the mno2 with mno4 would provide a better yield? I don't know that much chemistry however but its just an opinion. considering that its a liquid phase oxidation and that mno4 has more oxidization capability I think it could be of some use. the only negative "things" I can imagine going wrong is (1) a small scale side-reaction producing
mno2 and h20? which I dont think will really harm the yields at all and (2) the other being safety issues, but you already have knowledge concerning oxidizers so I dont think safety problems are an issue

=neat experiment, and nice thread


You mean KMnO4?

KMnO4 will probably give a lot of benzoic acid instead. Just like oxidation of piperic acid to piperonal.

[Edited on 4-10-2011 by shivas]
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[*] posted on 24-10-2011 at 06:43


Could Na2SO3 be used in purification of benzaldehyde instead of NaHSO3? Is there a big difference?
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simba
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[*] posted on 27-10-2011 at 05:34


Quote: Originally posted by Alastair  
Could Na2SO3 be used in purification of benzaldehyde instead of NaHSO3? Is there a big difference?


Don't know about Na2SO3...but N2S2O5 can be used as a substitute.
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[*] posted on 10-12-2011 at 02:37


Reference


Remember, for some reason known only to the gods of Olympus, I no longer receive emails on reply. So you may be better PM'ing me if you've got any questions as I won't necessarily look at the threads for another 6 months or more; or I'll entirely forget I posted resuts to them.

Quote:
Ferrous-Copper Catalyst: Toluene (7.6 g.), water (35 ml.), ferrous sulphate (0.110 g.) heptahydrate, cupric acetate (0.072 g.) and methanol (8 ml.) are placed in a 250 ml. reactor.Sodium persulphate (47.05 g.) in an aqueous-methanol solution of sodium persulphate is added slowly to the mixture which is maintained at 70.degree. C., in an atmosphere of nitrogen and under agitation.The organic phase is separated after two hours and the aqueous phase is extracted with ethyl ether.The combined organic phases are distilled to afford 8.29 g. (95% yield) of very pure benzaldehyde (compared against a pure sample).


-Patent, Process for preparing aromatic aldehydes and ketones, Maggioni, March 27 1979, Filing number 4146582
Experimental


3.783g of toluene are added to a 100ml RBF. The salts were then added and the necks rinsed in with 4ml of methanol and 17.5ml of water. The central neck is stoppered and a gas tap is connected to each side neck. The flask is placed in the freezer at -30C.

Meanwhilst, 23.5g of sodium persulphate are weighed out and added to a separatory funnel. 50ml of water are added to this and it is vigorously shaken to solvate.

The flask is removed from the freezer and immediately placed in it's mantle, with a condenser now in the central neck and the stopper moved to the top of this. A vacuum is drawn through one side neck (remembering to also apply the vacuum to the argon line), it is shut off and argon allowed to enter through the other. The process is repeat 5 times before closing both taps with the flask at 1 atm of argon. Strong magnetic stirring is used throughout. Heat is applied gradually until a solid reflux from the condenser is seen. The mantles setting is noted.

Once reflux is obtained, the stopper is removed from the condenser and the drip tip of the funnel is inserted against a very gentle flow of argon. The persulfate solution is added as slowly as possible.

With the addition complete, the stopper was replaced in the condenser as the argon was switched off. The reaction was timed from the start of reflux and heating was removed after 2 hours. The entire setup was then removed from the mantle and placed in a small bath with a few ice cubes to cool.

The soon cooled contents of the flask were then emptied into a separatory funnel and 20 to 25ml of dichloromethane were added; shaking can be rather intense without a persistent emulsion, but the first separation will take time to settle well. This was decanted and stored, with 3ml of water being placed over the extract in storage. Four additional extractions were made with DCM at 5ml each, for a total of 40 to 45ml.

The aqueous layer was discarded and the funnel rinsed before returning the pooled organics. An additional 3ml of water was added (for 6ml in total) and vigorous, continuous shaking carried out for 5 minutes (timed). The funnel was left to separate for 6 minutes before recollecting the organic phase (in an aqueous rinsed flask) and discarding the aqueous. The drip tip of the funnel was dried with a length of tissue before returning the organic phase, to which 6ml of brine was then added. It is now acceptable to shake the funnel as hard as is physically possible and this was done for over three minutes. Two hours later, the organic phase was decanted to clean and acetone dried storage flask, blanketed with argon, stoppered and stored in the freezer at -30C.

The process was repeated again with 3.802g of toluene, verbatim bar that the flask was left to stand in cool water overnight prior to extraction, and that it only required 30ml of DCM to reach a colourless organic phase.

The two organic pools from these two runs were loaded into an all in one still with a short fractional column and head moulded into place. The glassware was repeatedly back purged with argon and then the dichloromethane removed at atmospheric pressure.

When the distillation ceased, the glassware was then placed under vacuum to remove any remaining traces of DCM, back purged with argon, put back under vacuum and the organic products were then distilled into a single flask, yielding an oily, colourless, aromatic liquid at room temperature.

The original mass of this flask was 44.96629g. It now weighs 49.76645g, giving a mass change of 4.80016g.

3.783g of toluene, plus another 3.802, gives a total substrate mass of 7.585g. The molar mass of toluene is 92.14 g/mol, and so 7.585g equates to 0.08232 moles. That of benzaldehyde is 106.12 g/mol, giving a complete conversion mass of 8.7g.

(4.8 / 8.7) x 100 = 55% from toluene

Errors and oddities


The flask is not an ideal size, it ends up with about 80ml in a 100ml, but it didn't cause any problems.

Most references use ether for extracting benzaldehyde, as they both float on the aqueous layer. I don't have any (supplier lost the order and then ran out of it), so I went with dichloromethane, not wanting to start with toluene and knowing the cyclohexane I have needs redistilling anyway (it's still purple from messing around extracting seaweed). Dichloromethane is denser than the aqueous and organic layer in the separation. So it needs considerably more than it would with less dense solvents to flip the organic layer down to the base of the funnel. One useful thing is that having it at the bottom makes for easier subsequent extractions of the aqueous layer (it can stay in the funnel and simply have some more DCM poured in). It also keeps it away from the atmosphere to some extent, since it's sat down at the base under the water, but doubt it's all that much of an issue.

I didn't have enough bisulphite to form the adduct from the results. And, my fancy snazzy ground thermometer had died, so I can't fractionally distill until the new ones turn up. As a result, I had to distill the results and apply some logic to estimate what was going on.

Someone else, in some other thread perhaps, suggested that a slight excess of oxidiser would be a good idea when oxidising benzyl alcohol or toluene to the aldehyde, as the result should be that all of the alcohol is converted to the aldehyde, tars or a small amount of benzoic acid.

Have a look at these melting and boiling points (they're all in Celsius and ordered from lowest BP up);

Toluene
MP -93
BP 110.6

Benzyl Alcohol
MP -15
BP 205

Benzaldehyde
MP -26
BP 178.1

Benzoic Acid
MP 122.38
BP 250

The boiling points sweep up, but the melting points do not. Indeed, the first three are all liquids below 0C, whereas the benzoic acid is a solid over 100C. It will solidify in a cold condenser.

After collecting the lower boiling materials and reaching a point where I could no longer remove anything from the glass, I stopped. On allowing the glass to cool, I discovered the remaining liquid rapidly solidified. Furthermore, and much to my enjoyment, it stopped within literally 10mm or so of leaving the still head, with the last drip on the way out remaining a liquid. And suggesting the benzoic has been largely left behind in the still.

Making the assumption that all of the lower BP's have been converted to tar, benzaldehyde or benzoic acid, the liquid collected should be mainly benzaldehyde.

This is certainly a leap of faith to make, and I doubt it is perfectly true, but I suspect it is reasonably so.

Yield seems kind of low there


It does.

I have followed the patent rather closely, even using vacuums and argon for the atmosphere as opposed to only blowing a stream of nitrogen in.

The only two differences that come to mind are that I used DCM rather than ether.

The copper acetate I generated months and months ago when I was playing around with jam jars and the new power supply in the kitchen. It was produced using acetic (not vinegar) in water with cleaned copper wire from a bit of Twin and Earth. So that should be rather clean indeed.









The iron sulphate came from some nails. I first gave them a boil in sulphuric to scrub their surfaces, then emptied it all out, gave it all a rinse, put them back in with some water and a corresponding amount of sulphuric and warmed them overnight. The next day, I ran that through a ?1?um filter paper to get any solid out and received a very faint (barely visible), soft, greeny blue solution. Overtime, I noticed some form of sediment appearing in this, perhaps an iron oxide. I have possibly made a mistake here and the iron is not functioning as it should be in the oxidation.

It is also possible my persulphate is not truly all persulphate, that might be worth investigating.

At least it demonstrates the oxidation with persulphate does function anyway. Someone else (magpie / len / woelen / another?) has gotten a yield over 50% from persulphate also, using water alone (no salts, no methanol).

I have also tried it from benzyl alcohol, which also works. Although it seemed easier to oxidise it all to tar.

The solution does indeed need to be at 70C before the reaction starts, and the oxidiser should only go in slowly, in solution, when it does. As adding it only partially dissolved seems to encourage tars. As does running the reaction vastly above 70C. I have tried it with neat benzyl alcohol and the result was nothing less than a total mess! Both phases in the flask were dark brown within minutes, despite being under argon.

I believe the original patent suggests the specific values it does for water and methanol in the flask for good reason. The methanol not only helps fix the BP towards 70C, but combines the toluene / benzyl alcohol phase with the water, allowing the oxidiser access to more substrate and better dilution as opposed to coming into point contact with smaller amounts; where upon it forms tars (e.g. my neat benzyl alcohol test, which was also a lot hotter than 70C).

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[Edited on 10-12-2011 by peach]




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[*] posted on 10-12-2011 at 04:12


I ran the cell as well, months ago. And whilst my thermometer was still functional; so I could be sure of what was coming out in a fractional column distillation.

I originally uploaded these to facebook, and then had to format my computer. Which meant downloading them all again. Facebook wrecked the file numbering, so then they needed downloading again to keep them in sequence. Then the upload tool decided the next file after 1 should be 10, 11, 12 etc. More file renaming... very tedious. With the notes missing in action due to the format, all I can do is comment on what I remember.

What I remember, is that this thing is stupidly huge for the substrate mass!

In some of the photos, I've switched the stirring off so you can see the layers. To restart the stirring would mean reaching in there with a glass rod and jabbing at the stir bar to get it free from the silt. I recall this yielding around 50% as well (although that is really pushing into the vague memories there). It was run as per the description (I can't find the reference patent now), but didn't go quite as to plan.

Generating the bioxide was fine! But running the substrate through was odd.

I would add the toluene, hold the cell temperature and wander off. As I'd transferred it from a nearly full 800ml beaker to a 3l beaker, I could stir it extremely hard. After the allotted time, I would come back and pipette off the top layer, and give it another extraction with toluene or cyclohexane (I think cycloknight asked at one point, how to remove the toluene such that it didn't interfering with other substrates or gradually contaminate the cell). They steam distill it in the patent, but then you need to keep track of the moisture content instead.

On the first attempt, I did not receive back the expected amount of aldehyde. More interestingly, the cell had barely changed colour. So I added some more toluene and ran it again for the set amount of time. Again, still not the complete amount and still the cell remained the incorrect colour.

A third time round, I was wondering what was going on! But returned and bingo, the cell had gone right back to a banana milkshake yellow and the yield of aldehyde was starting to make a bit more sense.

The initial thought would be, all the rest of the yield had evaporated off as toluene, before oxidation. But I was also getting toluene in the results. And not vast amounts of tar or higher oxidation products.

I am still not entirely sure what happened there, but can only think of running this in a flask with a condenser on it, to ensure the amount of toluene going in, stays well contained, and to perhaps use some excess to ensure there's enough there, well mixed with the aqueous phase, for it to complete in one go. I didn't want to run it in a flask initially as oval bars aren't as good as the flat ones for stirring, and I don't have a 2l sized mantle that'll stir at the same time, or an overhead stirrer. It was also easier to make the electrodes for a beaker and I would be less bothered about damaging the beakers than a 2l, 3 neck flask.

The cell is fun to do, it's not specific to toluene and it yields reasonably, but boy o' boy is it a monster!

I dumped the cell it's self back out and into a HDPE bottle at the end, so I can always reuse it at some later date for something else; quite easily (only needs regenerating).

I would have put a photo up of the cell at the end of the process, banana yellow, but that went with the format.

Photo gallery.


This sheet of lead actually spent it's life as the bend at the back of a toilet. I cut a slit in it, spread it out flat, then proceeded with some heavy duty wire brush in a hand drill cleaning. After that it got a wash with some acid and then another clean with the wire brush. Sparkly. MeMe the cat is getting in on this photo.
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I'll hang onto that and maybe have a go at some lead salts with it. Lead cuts like hard cheese when using a hand saw, it's a sumptuous feeling. After cutting them, I ran a file over the edges to make them pretty. I put the sheets back in the beaker with the stir bar and bumped them off the top of the bar, so as to determine how high they'd need to be to ensure the the bar wouldn't start banging into them overnight.

I then bent a lip on them, hammered the lip flat and bent them around a large can of tinned fruit, approximately the same size as the beaker it's self.
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Need to be careful with these things involving electricity that you don't use wire that is going to melt in the middle of the night and torch the house. My cell pulled 5 amps at it's maximum. This cable can easily manage 5 amps (it's 13 amp mains flex). I also soldered the leads to the electrodes so they wouldn't be constantly making and breaking, or giving weird voltage / current readings.
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I'm not using fancy clean acid when it needs so much of it. That's drain stuff. It's concentrated, but clearly mucky due to contact with some organic at some point in the bottling. To make the colours more true to themselves, rather than contamination, I got the acid nice and toasty warm and began adding 35% peroxide to destroy the carbonaceous stuff. Careful.
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It took a while to go, but you can see it's fizzing out of existence.
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Meanwhilst... weighing out the equally monstrous quantities of salt.
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Acid's looking much better. Needs to be diluted down. Water content is an issue the patent mentions.
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Water into scalding hot concentrated acid right? :D Nah... not right, so again, do be careful if you repeat the process. I am dripping it in, slowly, with cling film (saran wrap) over the top to keep any spitting inside the beaker.
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Salts are in, Nesquick pink milkshake achieved. Probably a little on the tangy side.
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Ready?
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The juice is loose.
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Ten minutes later. Again, I found I had to cling film the top of this. Right from the start, even though it's not all that warm, the little bubbles popping around the electrodes were flicking spots of acid around.
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I think I calculated it'd take about 10 hours at the original current, can't remember. But I did start drawing a graph of the voltage against the current, with the temperature and a predicted end point. I then averaged the line as I was moving along to work out how much current had gone through.

The blue line is voltage, the red is current and the gray pencil line is temperature.

Notice the maximums on the supply a few photos up. I could not get anymore through it than it shown on the graph. I might have a look into making porous lead electrodes, if only for the fun of trying; does anyone have an information on how it's produced? The supply may not be a super nice Lambda one, but I am confident it can manage more than the 25 or so watts going through there (as I've seen it do so).
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The temperature was held at a continual 50C throughout the toluene's visit.
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Oooooo!

15kW, programmable. :D

Dear Santa...



[Edited on 10-12-2011 by peach]




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[*] posted on 15-12-2011 at 20:37


Thanks for that Peach. The photographs were excellent. For completeness would you please cut & paste the amounts and times from the earlier post so that it is all in one place. It would make a nice PDF.
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[*] posted on 23-12-2011 at 21:23


Quote:
It was run as per the description (I can't find the reference patent now), but didn't go quite as to plan.


You made the same mistake myself and everyone else has so far, you just tossed in the Toluene and stirred when the patents say to add the oxidizer to warmed toluene drip wise. I honestly feel this will make a huge difference. Huge enough that I am going to set back up a similar cell that generates Mn(IV) oxidizer because I have faith that this minor change will greatly affect the yield.





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[*] posted on 24-12-2011 at 00:06


Quote: Originally posted by Sedit  
Quote:
It was run as per the description (I can't find the reference patent now), but didn't go quite as to plan.


You made the same mistake myself and everyone else has so far.


The cell and manganese oxidiser come from US patent 808095.

Quote:
After the water evaporated during electrolysis has been replaced, the entire electrolyzing mixture is stirred together with four kilos of toluene in a closed lead-coated receptacle provided with a stirrer. The temperature is maintained at 50 degrees centrigrade.


No mention of dripping it in there. Besides, the electrolyzing mixture of which he speaks is packed so full of solid it takes effort to stir it, let alone drip it. The results also tend to be under oxidised as opposed to over, even when the substrate is simply poured in and left to stir at 50 degrees Celsius for hours. I actually fell asleep on the second go through and left it going for some ridiculous amount of time, returning to find it still hadn't gone to completion and needed more toluene.

The cell seems to benefit from using an excess of toluene and churning it as hard as possible to get the two into contact. Mine was stirring hard enough I could see the bottom of the beaker and the organic layer disappeared until the stirring was switched off and the contents allowed to settle. Harder than that.

You may be thinking of US 4146582.

Quote:
The temperature of the rection mixture is raised to 80°C and a flow of nitrogen is fed to the reactor under fierce agitation while drip feeding a solution of sodium persulfate (103.4g of Na2S2O8 in 335ml of H2O).


In which case, I did drip the oxidiser in and with the solution at that temperature, being stirred and under argon.

There are only two possible faults with my version of the persulphate method.

I used DCM as opposed to ether to extract the result.

More importantly, I could see cloudiness in the filtrate of the iron sulphate I was using, suggesting one of the catalysts may not have been in such great condition.

I have some supplier benzaldehyde spare if you guys ever tire of running cells etc. Personally, I have two other entirely none benzaldehyde related things I want to get on with this week and next, so it may be a wHile before I retry the persulphate oxidation. I've got a feeling I may do, as it is already nagging at me that something has gone a little too far amiss on the yield versus his claim. One of said things is making a decent amount of ether (as the supplier lost my bottle of it and then ran out of it), which would also solve one of those two questions. Although, I seriously doubt it was swapping ether for DCM that caused the change in yield, and suspect the iron sulphate.

PM me if you want some minus this twenty page thread of effort.

Quote:
He doesnt state how many seconds that were between each drip of cinnamon as it dripped into the 2L boiling solution of water and NaOH and he doesnt state how long it took for the product to be completely distilled.

If I was to use the same amount of cinnamon oil that cyclonight used but instead of using 2L of boiling solution of water and NaOH like he used, say I used an 8L of solution instead, does that mean I would need four times as much steam pressure to get the same amount of product to disstill over?


Set the drip rate so it corresponds, roughly, to the rate at which it's appearing in the receiver. Failing that, just go as slowly as the funnel will allow.

Pressure wise, no, it's the same pressure. The only changes you'd make would be with regards to the amount of cinnamaldehyde used. The more of it that goes in, the more steam volume needed and the longer it takes for it to all go across to the receiver. Also, as he and the patent applicant note, the pH of the solution can fall too low as the reaction occurs. Using more feedstock, you'd likely have to add some more base as it went along.

The glassware is not pressurised by the steam in cycloknights example. It will be passing through at approximately 1 atmosphere of pressure. Four times that would be about 60 psi. In a glass flask, that will likely cause the flask to burst as most glassware is tentatively rated for 10 or 15 psi max.

[Edited on 24-12-2011 by peach]




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[*] posted on 25-12-2011 at 03:17


I cleaned up the last two pages of the thread by splitting of the off topic beginner discussion on the cinnamaldehyde retro-aldol reaction that questions enforced for the last couple of months. The posts are now in the new thread he created for this purpose: https://www.sciencemadness.org/whisper/viewthread.php?tid=18...

I hope this thread will stay clear of any such fruitless off topic discussion from now on.
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[*] posted on 25-12-2011 at 03:42


sorry guys



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[*] posted on 25-12-2011 at 03:51


Hye I clicked on the link and it doesnt take me to the thread...... whats going on?



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[*] posted on 1-1-2012 at 22:21


Theres all this talk and excitement around liquid phase oxidation of toluene to benzaldehyde.

Has anyone tried the oxidation of toluene to benzaldehdye using the vapour vase method where titanium catylist is used?




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[*] posted on 2-1-2012 at 11:55


Here's a good site for making benzaldehyde from toluene by oxidising the toluene in the presence of sulfuric acid and manganese dioxide.

http://www.faizkaskar.8k.com/processelection.html




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[*] posted on 3-1-2012 at 23:26


You know, when I think of it, I realise that the toluene oxidation method realy isnt so bad.

To be honest with you, theres really two things about it that I dont like:

1) it's very time consuming and difficult to keep the cell clean of benz and tol and byproducts afterusing it the first time.

2) I hate doing vacuum disstilations and having to use scientific glassware.

So here is a sugestion that I think is worth you trying. In stead of vacuum disstilling the benzaldehyde out, just shake it with a solution of sodium bisulfite and the benzaldehyde will precipitate. Then add NaOH or ever bicarb powder to break up the aduct and this will result in pure benzaldehyde. It's quick, easy and doesnt require all that bullshit disstillation stuffing around and equipment.

Has anyone actualy tried using the sodium bisulfite method to precipitate the benzaldehyde out of the toluene when usig the electric cell to make benzaldehyde?




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[*] posted on 3-1-2012 at 23:33


Quote: Originally posted by Sedit  
Quote:
It was run as per the description (I can't find the reference patent now), but didn't go quite as to plan.


You made the same mistake myself and everyone else has so far, you just tossed in the Toluene and stirred when the patents say to add the oxidizer to warmed toluene drip wise. I honestly feel this will make a huge difference. Huge enough that I am going to set back up a similar cell that generates Mn(IV) oxidizer because I have faith that this minor change will greatly affect the yield.


How has this experiment been going?




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[*] posted on 3-1-2012 at 23:34


Have you even tried this method by any chance? It should be steam distilled out nothing more. Everything else is a pain in the dick including solvent extraction.




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[*] posted on 4-1-2012 at 00:43


Quote: Originally posted by Sedit  
Have you even tried this method by any chance? It should be steam distilled out nothing more. Everything else is a pain in the dick including solvent extraction.


As a matter of fact I have tried this method, I was using this method for like six straight months. I was boiling out the toluene at 115C to 120C and then I was vacuum disstiling out the benzaldehyde at around 90C. I hated the whole procedure because I wouldnt get anymore than 75ml :(

It sucked arse




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[*] posted on 4-1-2012 at 00:58


Have you attempted steam distillation to avoid the messy workup by any chance?

I aways put a mark on the flask where the oxidant level was before steam distilling incase I lose some fluid altering the concentration along the way. Start heating the flask and once its up to temperature pass steam into it and collect the vapors.





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[*] posted on 4-1-2012 at 05:55


Quote: Originally posted by Sedit  
Have you attempted steam distillation to avoid the messy workup by any chance?

I aways put a mark on the flask where the oxidant level was before steam distilling incase I lose some fluid altering the concentration along the way. Start heating the flask and once its up to temperature pass steam into it and collect the vapors.


I never needed to do a steam distilation because the vacuum disstilation worked perfectly. I just hated having to work with all the delicate and expensive and elusive glassware.




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[*] posted on 4-1-2012 at 05:57


Quote: Originally posted by Sedit  
Have you attempted steam distillation to avoid the messy workup by any chance?

I aways put a mark on the flask where the oxidant level was before steam distilling incase I lose some fluid altering the concentration along the way. Start heating the flask and once its up to temperature pass steam into it and collect the vapors.


Theoritically it should be easier and quicker to just use sodium bisulfite to precipitate it out and then just add bicard to it to convert it back to an liquid.




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[*] posted on 4-1-2012 at 19:31


No because you are steam distilling it directly out of the oxidant without the need of excess Toluene to extract it.




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[*] posted on 5-1-2012 at 04:49


Quote: Originally posted by Sedit  
No because you are steam distilling it directly out of the oxidant without the need of excess Toluene to extract it.


So you mean to say that after the toluene i the cell had converted to benzaldehyde, you blow steam through the whole discharged cell to lift ou the formed benzaldehyde with them steam where it is cndensed with the steam?




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[*] posted on 5-1-2012 at 13:04


Yes.




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