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redox
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Quote: Originally posted by questions  | Our friend "cyclonknight" described an attractive process for making benzaldehyde from cinnamon oil by slowly dripping the cinnamon oil into the
already boiling water with dissolved NaOH at around a PH of 12 to 13.
What I dont understand is that on the wikipedia they say that benzaldehyde is converted into two other chemicals when exposed to highly concentrated
NaOH, and I quote
"Benzaldehyde undergoes disproportionation upon treatment with concentrated alkali (Cannizzaro reaction): one molecule of the aldehyde is reduced to
the corresponding alcohol and another molecule is simultaneously oxidized to sodium benzoate."
So if the cinnamon oil is being converted to benzaldehyde, and is steam disstilled out, why isn't the benzaldehyde being converted into other products
as described by the wikkipedia? |
Questions, you have posted this message in at least four places. Crossposting is not acceptable and it is confusing.
Please do not crosspost again.
My quite small but growing Youtube Channel: http://www.youtube.com/user/RealChemLabs
Newest video: Synthesis of Chloroform
The difference between chemists and chemical engineers: Chemists use test tubes, chemical engineers use buckets. |
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chucknorris
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| Quote: Originally posted by Hilski | | Dry silica gel (5 g) was placed in a 100-mL round-bottom flask containing a magnetic stirring bar and fitted with a rubber septum. Jones reagent
(1.5mL, 12 mmol) was added slowly from a syringe to the vigorously stirred silica gel. After complete addition of the reagent, stirring continued
until a free-flowing orange powder was obtained (less than 5 min). Methylene chloride (25 mL) was added to the above flask. A solution of benzyl
alcohol 1a (396 mg, 3.66 mmol) in methylene chloride (5 mL) was added slowly from a syringe through the rubber septum to the stirred heterogeneous
mixture. The orange SJR turned dark green/brown immediately. After complete disappearance of the starting benzyl alcohol as indicated by TLC (10 min),
the reaction mixture was filtered through a sintered glass funnel, the solid residue was washed with methylene chloride (75 mL) and the washings were
added to the filtrate. Solvent was removed from the solution under vacuum to produce a colorless oil (331.6 mg, 85.3% yield) which was pure
benzaldehyde according to NMR and IR data. |
Is it really necessary to use such a huge amounts of DCM to dissolve all that stuff? I mean like, when you want to use 39.6g of benzyl alcohol which
will yield no more than ~30 grams of benzaldehyde, you would have to use hegemonic THREE LITERS of DCM for that??
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bamboula
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| Quote: Originally posted by DJF90 | | For a start, the paper claims acetic acid is required for the oxidation. Secondly, the paper runs the reaction in an ice bath. And finally, your
volume of solvent is far off if a direct scale-up is attempted. Perhaps you should try new reactions following the experimental procedure outlined in
the reference and on a small scale to avoid such dangerous situations and the large waste of materials. |
sorry for bumping an old thread
DJF90 can you tell me where i can find this paper ?
thx alot
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SM2
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Nicodem,
Your SmartAs they come. Just don't understand the reasons behind your anti-social aspects, exhibited on our SM board. You are a genius, no doubt.
Now just be nice here. Find people who truly deserve to be taunted and abused. Like the evil, dysfunctional Fed DOJ, who ruin people's lives every
day with their seemingly unlimited, unchecked power. Fed prosecutors can virtually prosecute any us citizen they want, regardless of merit. (off
topic, sorry). Other than that, you are a tremendous asset to SM.
SIMBA: Easy-Peazy. Just take a nice slog of bleach, and add a little NaOH (we want to keep the pH up a bit). Mag stir, and slowly add your benzyl
alcohol. It is simple, uncomplicated, fast, and very forgiving. Sep it. I'd distill, but you don't actually have to. The RXN is very clean, and
the mechanism is analogous to using hypochlorite (aq) to form aldehydes from some amino acids. Like phenylacetaldehyde from phenylalanine.
Nicodem probably knows a hell lot more if your really interested. Just remember, someone of his caliber will not accept any sloppy thinking.
Carefully proof read your question, do as much research as you can, and if you don't know something, admit it. Supply all the info you can garner.
In this way, experts are able, at their discretion, to give you their best answer without having to waste their precious time muddling through a bunch
of gob dilly gook.
"Old men who speak of victory
shed light upon their stolen life
they - drive by night- and act as if they're
moved by unheard music." B. Currie
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Dr.Bob
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Using solid supported reagents does require lots of solvent, but in many cases the solvents and/or solid supports can be reused. Often simply
washing the used silica gel with new reagents will reactivate it and it can be reused a few times at least. As well the DCM can be easily rotovap'd
or distilled off and reused many times. So they are not perfect, but easily scalable by either continous flow or small batches and reusing the
materials. Many other solid supported reagents can be reactivated (but not all). But they can allow for very simple reactions at times.
And people here should head the warning that scaling up reactions should be done slowly. If the procedure says 1 g, try it first, then try 10 g then
go to 100 g. I have seen several large messes made in the same manner. Also pay attention to the order of addition. As noted by SM2, sometimes if
you mix certain things first, the reaction will be more easily controlled, often the paper specifies a specific order, and I have seen many people
ignore it to bad results. Unless you are familiar with a reaction, the best way to reproduce it is the exact way it was done before, making changes
without reason will often give bad results. It is not always possible to redo exactly, but the closer the better. Few people cool a reaction in ice
just because, so if they say to do it, there is likely a reason.
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bamboula
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| Quote: Originally posted by SM2 | Nicodem,
Your SmartAs they come. Just don't understand the reasons behind your anti-social aspects, exhibited on our SM board. You are a genius, no doubt.
Now just be nice here. Find people who truly deserve to be taunted and abused. Like the evil, dysfunctional Fed DOJ, who ruin people's lives every
day with their seemingly unlimited, unchecked power. Fed prosecutors can virtually prosecute any us citizen they want, regardless of merit. (off
topic, sorry). Other than that, you are a tremendous asset to SM.
SIMBA: Easy-Peazy. Just take a nice slog of bleach, and add a little NaOH (we want to keep the pH up a bit). Mag stir, and slowly add your benzyl
alcohol. It is simple, uncomplicated, fast, and very forgiving. Sep it. I'd distill, but you don't actually have to. The RXN is very clean, and
the mechanism is analogous to using hypochlorite (aq) to form aldehydes from some amino acids. Like phenylacetaldehyde from phenylalanine.
Nicodem probably knows a hell lot more if your really interested. Just remember, someone of his caliber will not accept any sloppy thinking.
Carefully proof read your question, do as much research as you can, and if you don't know something, admit it. Supply all the info you can garner.
In this way, experts are able, at their discretion, to give you their best answer without having to waste their precious time muddling through a bunch
of gob dilly gook. |
SM2 what are the yield with this reaction ?
do you have some reference?
also do you know where can i find the paper i mentionned above ?
thx
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SM2
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CLIP...SM2 what are the yield with this reaction ?
do you have some reference?
also do you know where can i find the paper i mentioned above ?---CLIP
It's been a long time, just no time any more even for simple experiments it seems, and can't even get you the reference off hand. BUT, I do remember
doing it several times, and yield seemed almost quantitative, especially when taking MW's into account.
It's simple and difficult to fuck up. Take maybe 32oz bleach (PLAIN, no added anything), and if you can find the 10% stuff, that's even better. Stir
in a teaspoon of NaOH. Room temperature for everything seems to work fine. Drop in your polytef coated magnet, and center, etc. Get a nice stir
going. Just a 1" tornado on top is sufficient. Use a sep to add your alcohol. First, let it drip in for a few minutes. You can definitely increase
the rate fairly rapidly, but just monitor the temp. Warm is OK. If it's getting hot, stop flow. Part of the runaway with the HTH method is also due
to the aldehyde reacting with some inerts in the 65% or so, Calcium Hypochlorite granules, and at high concentration, with an abduct then playing a
2ndary role. It reduces yields, and is unpredictable and dangerous, IMO. But I am very conservative-a true coward in some respects if there is any
chance of run away. I guess my worst nightmare might be if I had to distill methyl nitrate or tetranitromethane, nitrogen trichloride, chlorine
dioxide. Ugh (sHuTtEr!). The original paper used HTH, and filtered the solution. It also used methanol as well if I'm not mistaken. Just Go with
the excess bleach, keep it alkaline, get a good stir going, and you'll be done in 20-30 minutes. When done in this manner, it is very forgiving, with
consistently high yields with no worries. Also, the aldehyde seems stabilized somehow by a small amount of perhaps a scavenger formed
If I may be so bold, would you mind explaining what your plans are for the benzaldehyde? It's such a cheap chemical, and unless you have nefarious
plans for it's usage, it's probably just easier to just fill out the DEA form and buy the pure stuff cheaply. Unless this is just pilot scale. It
all depends on how much you need.
You also can make it by stirring in some nano antease TiO2 into a cup of toluene, exposed to an ordinary black light while bubbling humid air through
the mix with a lava stone bubble disperser, and mag stirrer. The TiO2 forms a gap when exposed to certain band widths of UVA. -OH anions will be
formed on the TiO2 (water is necessary to form the hydroxyl). This too is very clean, but takes quite a bit longer. The amount of catalyst is a
factor, as is the intensity of the UVA. Too much TiO2, and your wasting light by reflecting it back out.
About drugs, DEA, if your not doing anything illegal with your goods, there is nothing to worry about. Believe me, they have almost ingenious ways of
knowing when one has crossed that line. It's just not worth it. And if you did succeed in making breaking bad, you'd get busted selling the shit.
And selling that shit is unethical as hell. If you want to experiment on a very small level just for your self, I guess the harm to society is not so
great.
One thing I absolutely can not stand, the OVERBLOWN, blown out of proportion mountain out of a molehill of contamination worries hysteria. It is
unfounded, and untrue, both in spirit, and in most practical ways. Saying a house needs a level of clean up you'd expect maybe if asbestos needles
covered in plutonium dust was sprinkled everywhere, with bottles of tetradioxin saturating the carpet.. What an over blown over reaction. I think
people who engage in this sort of work for our federal government, are largely the Chuck Norris type, who feel they are somehow sexy and important.
They are actually delusional, and buy in to the party line just as the audience for any N. Korean Kim Jung Shit. The Federal Govt is broken, and
beyond fixing. Sure, there are some good employees in fed jobs, but every federal worker, including every corrupt politician and policeman. Every
"Special Agent" man - they are ALL 2nd class citizens. You see, they are public servants. OK rant over, sorry, someone indeed DID pee in my corn
flakes today!
[Edited on 2-5-2014 by SM2]
"Old men who speak of victory
shed light upon their stolen life
they - drive by night- and act as if they're
moved by unheard music." B. Currie
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bamboula
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| Quote: Originally posted by SM2 |
CLIP...SM2 what are the yield with this reaction ?
do you have some reference?
also do you know where can i find the paper i mentioned above ?---CLIP
It's been a long time, just no time any more even for simple experiments it seems, and can't even get you the reference off hand. BUT, I do remember
doing it several times, and yield seemed almost quantitative, especially when taking MW's into account.
It's simple and difficult to fuck up. Take maybe 32oz bleach (PLAIN, no added anything), and if you can find the 10% stuff, that's even better. Stir
in a teaspoon of NaOH. Room temperature for everything seems to work fine. Drop in your polytef coated magnet, and center, etc. Get a nice stir
going. Just a 1" tornado on top is sufficient. Use a sep to add your alcohol. First, let it drip in for a few minutes. You can definitely increase
the rate fairly rapidly, but just monitor the temp. Warm is OK. If it's getting hot, stop flow. Part of the runaway with the HTH method is also due
to the aldehyde reacting with some inerts in the 65% or so, Calcium Hypochlorite granules, and at high concentration, with an abduct then playing a
2ndary role. It reduces yields, and is unpredictable and dangerous, IMO. But I am very conservative-a true coward in some respects if there is any
chance of run away. I guess my worst nightmare might be if I had to distill methyl nitrate or tetranitromethane, nitrogen trichloride, chlorine
dioxide. Ugh (sHuTtEr!). The original paper used HTH, and filtered the solution. It also used methanol as well if I'm not mistaken. Just Go with
the excess bleach, keep it alkaline, get a good stir going, and you'll be done in 20-30 minutes. When done in this manner, it is very forgiving, with
consistently high yields with no worries. Also, the aldehyde seems stabilized somehow by a small amount of perhaps a scavenger formed
If I may be so bold, would you mind explaining what your plans are for the benzaldehyde? It's such a cheap chemical, and unless you have nefarious
plans for it's usage, it's probably just easier to just fill out the DEA form and buy the pure stuff cheaply. Unless this is just pilot scale. It
all depends on how much you need.
You also can make it by stirring in some nano antease TiO2 into a cup of toluene, exposed to an ordinary black light while bubbling humid air through
the mix with a lava stone bubble disperser, and mag stirrer. The TiO2 forms a gap when exposed to certain band widths of UVA. -OH anions will be
formed on the TiO2 (water is necessary to form the hydroxyl). This too is very clean, but takes quite a bit longer. The amount of catalyst is a
factor, as is the intensity of the UVA. Too much TiO2, and your wasting light by reflecting it back out.
About drugs, DEA, if your not doing anything illegal with your goods, there is nothing to worry about. Believe me, they have almost ingenious ways of
knowing when one has crossed that line. It's just not worth it. And if you did succeed in making breaking bad, you'd get busted selling the shit.
And selling that shit is unethical as hell. If you want to experiment on a very small level just for your self, I guess the harm to society is not so
great.
One thing I absolutely can not stand, the OVERBLOWN, blown out of proportion mountain out of a molehill of contamination worries hysteria. It is
unfounded, and untrue, both in spirit, and in most practical ways. Saying a house needs a level of clean up you'd expect maybe if asbestos needles
covered in plutonium dust was sprinkled everywhere, with bottles of tetradioxin saturating the carpet.. What an over blown over reaction. I think
people who engage in this sort of work for our federal government, are largely the Chuck Norris type, who feel they are somehow sexy and important.
They are actually delusional, and buy in to the party line just as the audience for any N. Korean Kim Jung Shit. The Federal Govt is broken, and
beyond fixing. Sure, there are some good employees in fed jobs, but every federal worker, including every corrupt politician and policeman. Every
"Special Agent" man - they are ALL 2nd class citizens. You see, they are public servants. OK rant over, sorry, someone indeed DID pee in my corn
flakes today!
[Edited on 2-5-2014 by SM2] |
lol thank you SM2
i just need a small quantity of it (50 ml) and since i had a small bottle of benzyl alcohol laying around i thought i could synth some benzaldehyde
since it's impossible to find where i live 
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Fantasma4500
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about calcium hypochlorite
i recall long time back i read about a guy who was making a guide on 'how to KClO3' or something similar
he used both NaClO and boiled it down, aswell as Ca(ClO)2 however when he used the calcium hypochlorite he had a smaller explosion, it was later
determined that NCl3 was the cause
Ca(ClO)2 --- consider NCl3 formation!!
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Nicodem
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Wow! He achieved a nuclear reaction by simply boiling down a calcium hypochlorite solution? I wander if it was calcium, chlorine or oxygen that
transmutated?
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Fantasma4500
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Yes!
or well i guess?
dont think he even started boiling it down, he just left it to dissolve in a litre of water and then it just went boom
as something explosive could be generated in situ it should be considered
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