Synth: Benzaldehyde

anime · Thu Apr 14, 2005 9:25 pm

[quote="IndoleAmine"]

Esplosivo · Thu Apr 14, 2005 10:55 pm

Sodium persulfate is available OTC but it is so easily and cheaply made that I prefer making a lot of it myself. I once managed to produce 2.5kg of sodium hydrogensulfite by bubbling SO2 through NaOH (it was intended for adduct formation, but I used only about 100g or so) at one go, which I aerially oxidized to sodium hydrogensulfate. It is practically free, although time consuming. This tendency to produce everything myself is probably due to myself being a maniac about large scale processes.

n00dle · Fri Apr 15, 2005 6:50 am

Explosivo,
could you possibly provide a more organised method for producing sodium persulfate from your sodium hydrogen sulfite? SWIM is interested.

Is this sorta the procedure..

To get so2 you could heat sulfur (perhaps in a modded microwave) to oxidise to so2, and send that to an NaOH beaker, and 'aerially' oxidise this with .. air? bubble air through it?

Sodium persulfate is used in a lot of reactions and since SWIM can't find any refs for using perborate this might be the way to go in terms of gentle oxidisers for toluene->benzaldehyde

anime · Fri Apr 15, 2005 12:39 pm

I guess you could synth it, but for $19/kilo I really don't might buying it, in bulk its even cheaper. (price goes down waaay).

Exposure to SO2 is never free, neither is exposure to HCl, NO or any other nasty gas Smile

. But I do agree making would ultimately be cheaper. Heh, this process does seem to scale very nicely.

IndoleAmine · Dreamreader Deluxe

n00dle: sodium peroxymonosulphate = sodium persulfate... Wink

Interesting stuff you found there, guys! Cool

(but making SO2 is a bit dangerous; if you can buy bisulfite or hydrosulfate, use that - or buy the persulfate directly, hehe)

i_a

bio · Working Bee

Esplosivo · Fri Apr 15, 2005 7:38 pm

Well, considered, making SO2 is neither dangerous and given the proper ventilation it is quite safe. Nothing is ever risk-free, especially when you go synthesizing stuff from the most basic chems. I use a metal can of a 1 Lt. capacity(yes, corrosion is great, but these cans are free of charge) with a lid which closes tightly on top, half-filled with pre-molten sulfur. Two glass pipes are fixed to the lid, using hard metal cement. One of the glass tubes is nearly in contact with the bottom of the can while the other goes nearly 0.5cm out of the lid. Through the long tube air is pumped with the use of a cheap aquarium pump. Before putting on the lid the sulfur is ignited by tossing in a burning match (with the aquarium pump already put on). To the other pipe is attached a plastic pipe leading to an inverted funnel in a concentrated NaOH solution (even Na2CO3 works well). SO2 is kept going until precipitation of a white crystalline solid stops (the start of ppt usually takes some time). The white solid is sodium bisulfite (sodium hydrogensulfite / hydrogensulfate (IV)). This can be aerially oxidized by bubbling air through its solution in water, or with H2O2 of any conc. It can also be used directly for the hydrogensulfite adduct with carbonyl containing compounds. Hope this helps.

nubee · Master Archiver

scanned from the book: "A Short Organic Chemistry - F. Sherwood Taylor - 1948", which i picked up at a second hand book store for 8$

IndoleAmine · Dreamreader Deluxe

IMO using SO2 for making BzCHO is like using hand grenades for frightening birds...

Excellent find you made there, nubee!!

nubee · Master Archiver

thanks

icecool · Insistent Chemist

Very nice info, I might try this soon and then I mean the one with MnO2 and H2SO4.
Is MnO2 out of battery's good enough?
And has anyone got some more info about this one, since it is easier to get (MnO2) then Na2S2O8 to oxidize toluene with CuSO4 for instance.

IndoleAmine · Dreamreader Deluxe

It sounds easier, until you try to filter off the remnants of a MnO2 oxidation and/or try to clean your glassware from it....

IndoleAmine · Dreamreader Deluxe

Does anyone know about usability of Na2S2O8 for oxidizing P2Pols to the corresponding phenylacetones? Also, does anyone have the boiling points of P2Pol and P2P at hand by coincidence? (ok I know them for p2p, but not for p2pol.. Wink

)

Thx in advance,

i_a

bio · Working Bee

2-Propanol, 2-Phenyl bp 202, 93 (13) D 0.9735 (20/4)

...........Is MnO2 out of battery's good enough?............

Yes, If removed from a NEW battery then washed and activated with HCl acid. Search the H files for a procedure to activate and beware that so called active MnO2 from your favorite chem supply house may not work very well if at all. This stuff needs to be activated and freshly precipitated immediate before use. At least if you expect anything near the published yields.

Sounds like IndoleAmine had some fun with the old MnO2 a time or two. Rolling Eyes

Last time I used the stuff (several moles) I swore "NEVER AGAIN'. A person has to experience all by himself the joys of working with the lovely black gunk from hell to fully appreciate IA's comments. After using every f.....g filter in the lab even toilet paper was tryed. Don't ask, still don't know why I did that other than shear frustration. Finally let it sit for a week or two and it all settled out just fine( if undisturbed).

Now, cleaning the glass, that's another story. Damn claisen had traces on it for months.

IndoleAmine · Dreamreader Deluxe

Hot sulfuric and/or SnCl2/HCl37% did the trick (either one of it or the combination, dunno; but finally it looke dlike glass again Wink

)

(several wide-mouthed erlenmeyers were simply discarded, since they're relatively cheap and the cleaning reagents are not in this case.)