There is a reaction that I need to use formaldehyde to synthesize a primary alcohol structure. I heated the paraformaldehyde to generate the formaldehyde and absorb it by dry THF, and got nothing from the NMR. Is there any better way that we can use formaldehyde from para formaldehyde?
I feel one should be assure of adding pure reagent in RM. i hope pure formaldhyde (gas) can be achieved by following method.
Formaline solution upon evaporation to dryness gives polymer of paraformaldehyde, have to wash with water and dried over P2O5 and heat upto 120 °C under vacuum results monomer (gas), which is passed through glass-wool filter cooled to -48 °C (CaCl2/ice mixture) to remove particles of polymer, then dried with P2O5 and then condensed in RB in liquid nitrogen.
Ref: book by Wilfred L.F. Armarego, Chrisitna Li Lin Chai, "Purification of Laboratory Chemicals" page no 164.
Mr John Boyd, can you give detail explaination about the procedure? i also have the same issue like Mr Weiran Wang.
You can get a formaldehyde solution over 60% or more if you reflux paraformaldehyde in ethanol or methanol for 30-60 minutes (you need a temperature to “crack” the paraformaldehyde). Good luck
Formaldehyde (not paraformaldehyde) is available. Even methanol-free formaldehyde solutions are available. You might not need to generate formaldehyde from paraformaldehyde since formaldehyde is available.
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