video tutorial Acetic anhydride via acetyl iodide

Name: video tutorial - Acetic anhydride via acetyl iodide
Uploaded: 2025-12-11T09:03:44.053Z
Duration: 12 min 50 s
Description: You've all heard of acetochloride, and we've made this in a previous video.

Explores making the iodine analog of acetyl chloride (acetoiodide) from iodine, acetic acid, and red phosphorus to substitute acetochloride in reactions.
Setups a 250 mL flask with 20 g iodine and 15 mL glacial acetic acid (excess) and adds 2.5 g red phosphorus slowly to control exothermic behavior; reaction yields a dark solution with iodine dissolved.
Simple distillation after reaction produces a brown, fuming distillate containing acetic acid, hydrogen iodide, and acetoiodide; HI fumes are corrosive and require venting; distillation proceeds with alloying precautions.
Test distillate: contact with water releases fumes; reaction with sodium acetate gives a strong acetic anhydride aroma, indicating acetoiodide presence; cooled distillate shows no free acetic acid solid.
Further distillation with sodium acetate yields a colorless distillate containing acetic acid and acetic anhydride; purification would require fractional distillation; distillate amount ~22 g.
Attempted recovery of starting iodine: oxidize iodide in the distillate with ammonium sulfate to iodine, yielding about 16 g (roughly 3/4 of the original iodine); HI loss significant on small scale.
A final experiment attempting to synthesize anhydride directly from reagents showed no acetanhydride formation; not feasible at this scale.
Conclusions: the procedure as described isn’t enough for purification on small scale; scaling would require extremely dry apparatus and conditions, especially for the first distillation; aluminum could replace red phosphorus in a staged process with an inert solvent and higher boiling solvent like xylene; alternative routes remain to be explored.