video tutorial Acetic anhydride preparation via the 'classic' method

Name: video tutorial - Acetic anhydride preparation via the 'classic' method
Uploaded: 2025-12-11T09:03:44.036Z
Duration: 7 min 20 s
Description: We'll be preparing acetic anhydride the...thing in this reaction is that your sodium acetate must be anhydrous and

Goal: synthesize acetic anhydride from acetyl chloride and dry sodium acetate.
Drying: sodium acetate must be anhydrous; oven-dried at 200°C for 4 h for best results (80 g used).
Procedure: cool sodium acetate in an ice bath with a thermometer; slowly add about 60 g of acetyl chloride (~55 mL) while keeping temperature below ~60°C to minimize loss of acetyl chloride; reaction forms a slurry as heat is generated.
Initial distillation: perform simple distillation to remove impurities; first liquid boiling starts around 110°C; crude distillate contains acetic anhydride with acetic acid and possibly ketones; distillation lasts ~1.5 h and the slurry becomes more solid as distillation proceeds.
Purification: fractionally distill using a 40 cm Vigreaux/Vigreux column because acetic acid and acetic anhydride boil ≈30°C apart; insulation improves efficiency; collect main product after head temperature rises above ~130°C; ventilation required due to irritating vapors; discard initial distillate.
Process details: the reaction was run twice and the products combined for purification; total distillation about 2.5 h; final distillate shows a yellow color transitioning to colorless product residue.
Product and yield: 130 g of pure colorless acetic anhydride obtained; average yield ~83% based on acetyl chloride used (doubling the first run); product has little initial aroma but later a pungent odor.
Water reaction: acetic anhydride reacts slowly with water, forming a small acetic anhydride bubble in cold water; overall reaction is slow.
Note: tar-like residue may remain in the reaction flask after purification; safety considerations include eye/respiratory irritation from vapors.