Chemistry Forums for Students > Organic Chemistry Forum
Vanillin reagent
awais:
I have made vanillin solution:
0.5g of vanillin in 20ml ethanol and 80 H2SO4 and this was warmed to 120°C. Now I don't know how to use this. I tried to dip my TLC in this solution but due to conc. H2SO4 the silica layer starts removing.
Plz guide me that how i can use this or may be i am wrong and what will be effect after applying this solution to TLC
Thanks
Borek:
--- Quote from: awais on September 14, 2006, 03:50:26 AM ---I have made vanillin solution:
--- End quote ---
I assume you needed it for something? Becasue ATM you have posted something like "I have made a solution, how I use it" which sounds like some abstract joke :)
--- Quote ---80 H2SO4
--- End quote ---
Please elaborate. 80 what of what?
Oh, and for answer you will probably have to wait for some organic chemist :)
russellm72:
Hi,
Normally you would make it up in say a 500 ml brown bottle that you can cap and store for a while. Normally as you said you dip your TLC plate in and remove carefully allowing any excess to drip off. The you heat your plate gently with a heat gun and your product spots should appear. It's a nice standard reagent and smells quite sweet too which helps.
Now if you say your silica is falling off it sounds like you have rubbish plates. I hope your not like an undergraduate and the plates are home made cause I remember those days and the silica didn't set well.
Normally I use glass backed or preferably aluminium backed plates that we buy in from a supplier and these pose no problem.
How much c.H2SO4 have you used? You dont need a bucket load.
R.
movies:
Vanillin stain doesn't have a very long shelf life, relative to other stains, so watch for it starting to go bad.
awais:
sorry guys, i wrote my question in hurry so misssed somethings. The amount of H2SO4 is 80 mL, which i think is quite high. I read the protocol send by some one(http://www.ux1.eiu.edu/~cfthb/research/handbook/TLCstains.htm). On this protocol the amount of H2SO4 is very less. might be this is problem. For TLC , i m using alumin. back plate and i think it is of good quality. If someone can write me the procedure of making this vanillin solution.
Thanks ;)
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