Rajesh R
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PENTAERYTHRITOL
hi friends .
i am doing reserach on pentaerythritol.could any one help me how to control the formation of tripentaerythritol and pentaerythritol mono formal in
reaction it self.
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glymes
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Do you mean pentaertythritol tetra nitrate or just pentaerythritol?
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Daffodile
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You could probably just control the rate of Alkaline Oxide addition, I think its needed for the final part of the reaction, forming a somewhat soluble
formate, and adjusting the rate of addition would adjust the rate of the reaction.
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glymes
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We need more info. What reaction? What chemicals?
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Bert
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Thread Moved
23-5-2016 at 18:59 |
bluamine
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You can make it by mixing acetaldehyde & formaldehyde in a (weakly) basic solution..
[Edited on 24-5-2016 by bluamine]
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Rajesh R
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pentaerythritol
it was only pentaerythritol
*reaction
farmaldehyde raect with acetaldehyde in presence of caustic
*@bluamine
reaction conditions
Fa -1250kgs with 11% and caustic was added at 48% (72 kgs)
molar ratio Fa/Aa -5.1
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bluamine
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If you are talking about caustic soda, it can be used but some books recommend using of calcium hydroxide or another weak base instead.
65-70°C
Theoretically, this is the reaction:
2CH3CHO + 8HCHO + Ca(OH)2 (catalyst) = 2C(CH2OH)4 + Ca(HCOO)2
The yield would be less than it's shown in the reaction
After mixing the reactives you should adding some sulfuric acid. Calcium sulfate will percipitate out. Filter it & then boil off the water.
I have read that using some oxalic acid with suhfuric acid can incfrease the yield. I never tried to do this reaction though.
Another thing to say is that calcium formate can be used to recover some of the formeldehyde by pyrolysis.
I hope other Madness mates will give you more informations[/size]
[Edited on 24-5-2016 by bluamine]
[Edited on 24-5-2016 by bluamine]
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greenlight
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Found this written down in some old notes, don't know where I got it from though or the accuracy...
To a mixture of 18.5g Calcium hydroxide and 75g formaldehyde in 500ml of water, 22g of acetaldehyde is slowly added.
The temperature of the mixture is maintained at 15 Degrees C during addition of the acetaldehyde and then gradually raised to 45 C.
The calcium is precipitated by adding oxalic acid and the calcium oxalate removed by filtration. The filtrate is is evaporated to dryness under
reduced pressure and the residue is taken up in 200ml of hot ethanol and the resulting solution allowed to cool. The pentaerythritol which separates
weighs 50 grams (73.3% theoretical) and melts at 258 C. Pure pentaerythritol melts at 260 C.
Be good, otherwise be good at it 
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Rajesh R
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Does molar ratio of Fa/Aa will make any difference in reaction
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bluamine
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What do you mean?
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gdflp
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Quote: Originally posted by Rajesh R  | it was only pentaerythritol
*reaction
farmaldehyde raect with acetaldehyde in presence of caustic
*@bluamine
reaction conditions
Fa -1250kgs with 11% and caustic was added at 48% (72 kgs)
molar ratio Fa/Aa -5.1 |
This is really NOT the place to be asking for help with manufacturing scale processes, especially of explosives precursors. There are many
considerations which must be taken at such a scale which can be ignored at small scale(~100g or less). A more appropriate route would be to hire a
chemical engineering consultant and have them assist you. Your lack of coherency is not helping anything either, and is somewhat suspicious.
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hissingnoise
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| Quote: | | Your lack of coherency is not helping anything either, and is somewhat suspicious. |
Indeed gdflp, he shows he has no understanding of the chemistry involved (Does molar ratio of Fa/Aa will make any difference in reaction)? and yet
talks of using more than a tonne of formaldehyde?
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