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nubee
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Sodium Bisulphite Prep./Synth.
Thu Mar 24, 2005 6:27 am |
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just (ctrl+c/ctrl+v)'d this, not confirmed -
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Sodium Bisulphite:--->
Sodium carbonate is covered with a layer of water--insufficient to dissolve it--and sulphur dioxide is passed into the mixture. After a time the solid disappears and an apple-green solution remains which smells strongly of sulphur dioxide. Sulphur dioxide may be obtained from a siphon of the liquid or generated by the action of conc. sulphuric acid on sodium sulphite. Sodium bisulphite solution may be obtained by dissolving the sodium bisulphite in water, but the solution so prepared does not act so readily with aldehydes and ketones as the syrupy apple-green solution described above. A freshly prepared solution should always be used for aldehydes and ketones. A saturated solution of sodium metabisulphite (Na2S2O5) is also applicable.
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hopefully a SWIM will confirm this...
found in:
Systematic Organic Chemistry - Cumming, Hopper,and Wheeler
used in:
Purification of Ketones by Sodium Bisulfite |
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Esplosivo
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Joined: 12 Feb 2005 |
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182.38 Points
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Fri Mar 25, 2005 1:32 pm |
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Well yes the process can be carried out as described. Instead of sodium carbonate though, sodium hydroxide can be used as follows.
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Sodium hydrogen sulphite is prepared in solution by passing sulphur dioxide to saturation in a cold solution of caustic soda (NaOH) or sodium carbonate (CO2 being in this case expelled). The salt separates out as a crystalline powder. If exposed to air it becomes slowly oxidized to sodium hydrogen sulphate (Sodium bisulphate) ... it crystallized from water it loses water and gives sodium metabisulphite.
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Hope this helps. |
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room temp
Sat Mar 26, 2005 1:56 pm |
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When one has the Sodium Metabisulfite, and IS trying to make a saturated solution,
Is best to add fresh H2O to an over abundant supply of the sulfite,
and pur off the top, after letting it rest 20 mins,
Or yo just keep adding till precipitation occurs?
Just for a test, I use acetone,
with I drip into my saturated solution,
You will see crystals form straight away, an know that it should work for the CHO's as well
syn |
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IndoleAmine
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18717.10 Points
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making bisulfite solutions
Sat Mar 26, 2005 5:29 pm |
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Make a satd. solution by dissolving NaMeBiSulf in dH2O until solids remain...
Then dilute with a little alcohol, wait until the small amnt. re-precipitated BiSulf has settled, then decant into CLEAN beaker and let sit 30 minutes (this aging is VERY important).
Now just add your carbonyl compound, stir and let sit again (preferably in the cold) to precipitate the bisulfite adduct. Filter off and rinse with dH2O, let dry.
(important: even the smallest concentrations of H+ or OH- will initiate the bisulfite adduct to break down again, so rinsing with distilled H2O is a must here)
To cleave the addition product again, just add dilute aequous acid or lye to the bisulfite adduct crystals, they will dissolve and give off your carbonyl compd. again, which can then be extracted.
(note: sodium/potassium metabisulfite can be interchanged with sodium/potasium bisulfite without any problems, since the metabisulfite generates bisulfite in situ. Only difference is that metabisulfite has approx 2x the molar weight and you only need to use 1/2 as much as with ordinary bisulfite. Both can be found at photography chemical suppliers for very cheap.....)
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java
Consumer
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Joined: 07 Feb 2005 |
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21794.14 Points
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Re: sodium bisulfite solution
Thu Mar 31, 2005 12:41 pm |
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Re: Sodium bisulfite solution
source: http://www.biochemicaldiagnostics.com/reagentprep.html
SATURATED SODIUM BISULFITE SOLUTION
Dissolve 25 grams of Sodium Bisulfite (or Sodium Metabisulfite which converts to Sodium Bisulfite in solution) in 50 mL of Deionized water. Shake well. Dilute 1:1 with Reagent D, **Phosphate Buffer, pH 6.0 for a total volume of 100mL. Shake well. Prepare monthly and store this reagent in a glass bottle with a Teflon or Polypropylene lined screw capped top.
** PHOSPHATE BUFFER, pH 6.0
Prepare 0.25M Potassium Phosphate, Monobasic, (34 gm KH2PO4/liter water). Initial pH is approximately 4.8. Adjust the pH upward to 6.0 with 0.25M Sodium Phosphate, Dibasic , (35.5 gm Na2HPO4/liter of water). (Reagent D)
Note: Posting the source/reference of information is important so as to keep our information authentic . |
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great
Thu Mar 31, 2005 1:00 pm |
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Yes, this is a really handy way for extracting BzCHO from those little almond essence bottles,
Since they can contain all sorts of exotic compounds, sugars, and the like,
It really makes you think how easy it is to get plentiful supplies of BzCHO from various sources,
You could boil Apricot kernal oil with water, to tranform it into BzCHO, extract with np, then do a bisulfite,
That would be grand,
Or just stick to the Cassia oil, and try it on that,
As we all know, steam distillation, can be a lengthy process,
but a quick extraction, and adduct seperation, should be a breeze
syn |
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IndoleAmine
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Fri Apr 01, 2005 12:30 am |
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Steam distillation of benzaldehyde ís very fast, and you can use a sep.funnel as receiver, to tap off the BzCHO that will separate to the bottom - very easy...
Note: sorry - have no ref for the bisulfite prep., since I wrote it down from my memory. Can be found in "Vogel's", "Organikum" or "Gattermann", or similar books I think. So you will have to trust me on this one - without any given ref...
(you don't trust me, right Java? Think I would want to fool everyone with this bisulfite preparation, no?)
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nubee
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Tue Apr 19, 2005 7:02 am |
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Quote: |
Sodium bisulphite often becomes altered when stored. A suitable solution may be made by covering sodium carbonate crystals with water and saturating with sulphur dioxide till an apple-green colour develops.
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Bumblebee
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Joined: 26 Mar 2005 |
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1718.58 Points
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Bisulfite OK to separate piperonal and phenylpropylalcohol ?
Sat May 07, 2005 10:19 am |
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i came in contact with the tematic of bisulfite adducts a time ago for, while i tried to extract piperonal from Hydrocinnamic alcohol and posted on the hive for help.
the thread ended with the suggestion to build a bisulfite adduct of the piperonal, and cleave it again to get the aldhyde back.
-could that function? I ask myself if it is possible to seperate the two materials with it...
and do i understand it right:
1.The sodium bisulfite solution is made shortly before extracting something with it. Buffer is not needed then or what??
2.the sodium bisulfite solution forms when i add NaMeBiSulfite to H2O?
Quote from the Hive post:
Quote: |
3_4_BumbleBee
(Stranger)
07-31-04 07:12
No 522931
piperonal and Phenylpropylalcohol?
Hey there
I found a compound for the conservation of cosmetics. the INCI says it consists of : 3,4-Methylendioxy-benzaldehyd, Phenylpropylalcohol.
Does anyone know this stuff? it is used to conservate fat/water mixtures and give them a smell of hyazinth.
of how many percent 3,4-Methylendioxy-benzaldehyd consists it?
the INCI gives the components in descending order, so i believe it is more piperonal!
it is widely available, so what do you think of it?
how to separate it? Fractional distillation with a 400mm Vigreux should do the job... 20°C difference between boiling points @ 760mm....
3,4-BB
ApprenticeCook
(Hive Bee)
08-01-04 02:24
No 523059
i cant tell if this is sources or not....
i cant tell if this is sources or not.... may just be bordering on it.....
If the product info doesnt tell you %'s, you could distill it to figure out....
But yes distill it to get your piperonal...
Nice.
-AC
Its just my opinion, but no-one listens to me anyway, and rightly so...
3_4_BumbleBee
(Stranger)
08-01-04 03:43
No 523072
i tink its not sources, because this compound...
imho its not sources, because this compound is used in pafumery and cosmetics widely around the world. I just know the tradename under what it is sold by any cosmetics suppliers. you will have to find out for yourself your local tradename for your country, but this seems to bee the mixture in what heliotropin is used in biocosmetics, along with 3-phenyl-1 -propanol, to make it more fluid at room temperature, other ingredients are not given in the INCI.
mainly aim at preservation for cosmetics, while searching.
swim ordered some, i will let you know of how much heliotropine it consists.
ApprenticeCook
(Hive Bee)
08-01-04 17:18
No 523150
in that case no its not...
in that case no its not... thanks for clearing that up...
Yeah well it would be interesting how much usefull material comes out of it...
Make sure you document it and share it...
-AC
Its just my opinion, but no-one listens to me anyway, and rightly so...
3_4_BumbleBee
(Stranger)
08-11-04 13:42
No 524885
Swibb gave me some of that mentioned stuff!
Swibb gave me some of that mentioned stuff!
It smells beautiful, sweet, Heliotrope-like. it is a light yellow, oily liquid, and starts to boil slightly at 235°C/760mmHg and turns into brown on further heating...
I think i should not try to distill it at atmospheric pressure?!?
what strength of vacuum will be needed? i try it with my old aspirator, but i don´t know how much mm/hg it does.... should be around 30-50 mmHg.
bb
starlight
(Hive Bee)
08-12-04 05:55
No 525048
boiling points
235C is the boiling point of 3-phenylpropanol-1. Boiling point of heliotropin is 263C.
Using a vacuum of 50mm of Hg should make these boiling points around 140C and 165C respectively (estimates may be out as they were calculated v. roughly using a nomograph).
Simple distillation will not do a good job of separting these two compounds as the boiling points are too close. Fractional distillation will do better.
Maybe there would be another way of separating the two, for instance dissolving the product in ether and then shaking with sodium bisulfite in order to form the bisulfite adduct. Someone with more experience of purification using bisulfite adducts could probably help you here as I don't know if it is practical to use it here for purification.
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re: Sodium Bisulphite Prep./Synth.
Sun May 08, 2005 9:00 am |
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Swiss can get almond flavoring in 0.5L containers for dirt cheap. The bottles are mostly propylene glycol with some water and benzaldehyde. Could Swiss drip the almond flavoring into the conc bisulfite solution and collect the benzaldehyde addition product? Or is the propylene glycol and or water in the flavour going to fudge that up?
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nubee
Master Archiver
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18618.86 Points
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Fri Jun 03, 2005 8:53 am |
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just a note that Sodium Meta/Bisulphite has been spotted in pottery and brew stores... |
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