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Nicodem
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Quote: Originally posted by shivas  | I'm a little puzzled by these bisulfite adducts, I tried extracting vanillin from solution last week, and nothing precipitated out of it. I mixed
sodium metabisulfite with cold water, allowed everything to dissolve, added to the vanillin solution and shook it, but no adduct crytals falled out.
Any idea what could be going wrong? |
Something would be wrong if you actually got a precipitate. It would mean that either your starting material contains impurities insoluble in water,
or that what you believe to be vanillin is actually something else.
I'm not sure what you want to achieve here, but if you wanted to isolate the bisulfite adduct, why didn't you simply follow the normal procedure?
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simba
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| Quote: Originally posted by Sedit | Possibly your starting material is low in Vanillin content, what was the source of the Vanillin solution?
http://www.sciencemadness.org/talk/viewthread.php?tid=13974#...
Over the counter Vanillin products are rather useless for obtaining Vanillin. I have tried a few times for the hell of it and they all only contain a
few mg of Vanillin at best. Also you never added Alcohol to precipitate the Adduct and if you have read this thread you will see that the bisulfite
adducts are soluble in water. |
I used vanillin essence from the local market, as you said, just for the hell of it. I did not add alcohol at first because it was already a solution
of vanillin and alcohol, but then after adding more alcohol to it the solution began turning milky white, likely because of the decrease in solubility
of bisulfite, but nothing falled to the bottom. I think I will be trying it with something else.
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Sedit
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After adding the alcohol the milkywhite precipitate you say was your adduct and some Sodium Bisulfite. Let the milky white precipitate settle over
night and recrystalize the few mg of material that these contain.
It sounds like you need practice with this so try it with acetone or MEK each would get you better results then this.
QUESTION:
Will an acetone adduct be flammable? I know they decompose with higher temperatures so once that is reached should the whole just not burst into
flames on ignition?
Knowledge is useless to useless people...
"I see a lot of patterns in our behavior as a nation that parallel a lot of other historical processes. The fall of Rome, the fall of Germany — the
fall of the ruling country, the people who think they can do whatever they want without anybody else's consent. I've seen this story
before."~Maynard James Keenan
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simba
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| Quote: Originally posted by Sedit | After adding the alcohol the milkywhite precipitate you say was your adduct and some Sodium Bisulfite. Let the milky white precipitate settle over
night and recrystalize the few mg of material that these contain.
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If you mean a few mg of vanillin and a large mass of bisulfite than you're correct...because thats what I've got.
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noviceBRchem
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Recovering adduct..
hello, my first post, i had problems recovering the ketone from the adduct with 20% sodium carbonate, when mixed, 2 layers werent form!! instead the
aquaus layer turned sligtly green and crystals sinked to bottom.... should i have two layer? oil and water?
how to procede? is a 10%hcl better for this purpose? or the ketone shoudnt return to oil condition, instead just extract the water layer with some DCM
?
should i heat until everything is dissolved?
PLASE help hehe
thanks for the help and sorry for my english!! (not first language) =)
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cal
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aldehyde
I did this procedure with almond extract and got an oily layer and the water layer immediately. After adding the isopro pyl alcohol.
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