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#Post#: 1217--------------------------------------------------
ethylene production
DIR By: sumaira aslam
Date: November 23, 2012, 11:03 am
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HI, If someone can help me finding stoichiometric conversion of
ethylene gas to formaldehyde? or simply 1mole of ethylene gives
? mole of formaldehyde ?
#Post#: 1225--------------------------------------------------
Re: ethylene production
DIR By: Michel
Date: November 24, 2012, 1:30 pm
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Hello Sumaira,
This is an interesting question. You could help us a lil bit by
providing some further information about the reaction.
What oxidizing agent is employed? Is it a photo-oxidation? What
catalysts? etc, as there isn't much literature on this
subject...
#Post#: 1228--------------------------------------------------
Re: ethylene production
DIR By: Potla
Date: November 25, 2012, 6:01 am
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I don't know about what's practically done, but CH2=CH2 should
give HCHO after Ozonolysis: O3/CCl4 followed by Zn/CH3COOH.
Or even maybe cold alkaline KMnO4 or OsO4 followed by NaIO4:
Lemieux Reagent, which does essentially the same thing as
ozonolysis...
HTML http://en.wikipedia.org/wiki/Lemieux%E2%80%93Johnson_oxidation
#Post#: 1232--------------------------------------------------
Re: ethylene production
DIR By: Michel
Date: November 25, 2012, 8:36 am
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--- Quote from: Potla link ---
>
> I don't know about what's practically done, but CH2=CH2 should
give HCHO after Ozonolysis: O3/CCl4 followed by Zn/CH3COOH.
> Or even maybe cold alkaline KMnO4 or OsO4 followed by NaIO4:
Lemieux Reagent, which does essentially the same thing as
ozonolysis...
>
HTML http://en.wikipedia.org/wiki/Lemieux%E2%80%93Johnson_oxidation
>
--- End Quote ---
Well, being posted in this board, I'm assuming it's for large
scale production?...If i'm correct, these methods are
uneconomical, the reagents involved are way too
expensive...otherwise, good for laboratory.
Hope we can get some clarification from the OP
#Post#: 1234--------------------------------------------------
Re: ethylene production
DIR By: Shiva
Date: November 25, 2012, 9:36 am
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Also, formaldehyde is a category I carcinogen.
Shiva
#Post#: 1263--------------------------------------------------
Re: ethylene production
DIR By: sumaira aslam
Date: November 27, 2012, 1:16 pm
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--- Quote from: Potla link ---
>
> I don't know about what's practically done, but CH2=CH2 should
give HCHO after Ozonolysis: O3/CCl4 followed by Zn/CH3COOH.
> Or even maybe cold alkaline KMnO4 or OsO4 followed by NaIO4:
Lemieux Reagent, which does essentially the same thing as
ozonolysis...
>
HTML http://en.wikipedia.org/wiki/Lemieux%E2%80%93Johnson_oxidation
>
--- End Quote ---
Well its true about expensive protocole but i am using it only
at laboratory scale. The method involves oxidant solution(KMnO4
and NaIO4) later Nash reagent(ammonium acetate+acetic
acid+acetyle acetone) is added ...the yellow color of
formadehyde so produced is read through spectrophotometer.
Many thanks to all replies hope this information may lead to
some final conclusion i-e., 1mol of ethylene produce how many
mole of formaldehyde?
#Post#: 1264--------------------------------------------------
Re: ethylene production
DIR By: Michel
Date: November 27, 2012, 1:17 pm
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In any case,
CH2=CH2 + KMnO4, Zn/AcOH ==>2HCHO
is a 1:2 mole ratio (stoichiometrically, 2moles of formaldehyde
is obtained from 1 mole of Ethylene)
In practice the reaction wouldn't proceed stoichiometrically,
there'll be a % yield.
I believe this is what you're interested in, Sumaira?
#Post#: 1265--------------------------------------------------
Re: ethylene production
DIR By: sumaira aslam
Date: November 27, 2012, 1:23 pm
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--- Quote from: Michel link ---
>
> In any case,
> CH2=CH2 + KMnO4, Zn/AcOH ==>2HCHO
> is a 1:2 mole ratio (stoichiometrically, 2moles of
formaldehyde is obtained from 1 mole of Ethylene)
> In practice the reaction wouldn't proceed stoichiometrically,
there'll be a % yield.
> I believe this is what you're interested in, Sumaira?
>
--- End Quote ---
Thank you so much for showing concern. Actually i want to
prepare a standard curve of known amounts of
formaldehyde...knowing the colour absorbance obtained through
spectrophotometer i want to calculate ethylene indirectly. I am
sorry if my question is not so clear!
#Post#: 1266--------------------------------------------------
Re: ethylene production
DIR By: sumaira aslam
Date: November 27, 2012, 1:28 pm
---------------------------------------------------------
--- Quote from: Potla link ---
>
> I don't know about what's practically done, but CH2=CH2 should
give HCHO after Ozonolysis: O3/CCl4 followed by Zn/CH3COOH.
> Or even maybe cold alkaline KMnO4 or OsO4 followed by NaIO4:
Lemieux Reagent, which does essentially the same thing as
ozonolysis...
>
HTML http://en.wikipedia.org/wiki/Lemieux%E2%80%93Johnson_oxidation
>
--- End Quote ---
Thanks Potla...yes this is the 2nd one i mean alkaline using
KMnO4 followed by NaIO4
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