video tutorial Can aluminium replace phosphorus for alcohol reduction

Name: video tutorial - Can aluminium replace phosphorus for alcohol reduction
Uploaded: 2025-12-11T09:03:43.821Z
Duration: 14 min 25 s
Description: We've tested this in a previous video....this is our last reaction video but we've got a few more interesting things

Goal: test whether aluminium can substitute red phosphorus in the iodine reduction of mandelic acid to phenylacetic acid using iodine and propionic acid as solvent.
Materials: aluminium foil (1.4 g), iodine (4.9 g), mandelic acid (2 g); propionic acid solvent; large excess aluminium; apparatus includes 250 mL flask, heating mantle, stirring, reflux condenser; initial tests show limited reaction at room temperature.
Mechanism overview: iodine and red phosphorus form PI3; PI3 iodinate the alcohol to form an intermediate; reduction by HI yields the alkane (phenylacetic acid); iodine is regenerated, continuing the cycle; aluminium iodide hydrolyzes with water to HI; aluminium hydroxide forms and is relatively inert; theory supports aluminium-assisted reduction.
Background: aluminium can react with iodine and alcohols to form alkyl iodides; precedence exists for Al/I2 systems with other substrates.
Experiment details: dissolve iodine and mandelic acid in propionic acid; gradually add aluminium; heat to reflux; color changes accompany reaction; crystals observed; reaction allowed to proceed and then cooled; mixture quenched with ice.
Workup: extract aqueous with dichloromethane; separate layers; evaporate solvent; attempted isolation of phenylacetic acid; aroma suggests absence of significant phenylacetic acid and presence of propionic acid; persistent aqueous layer with faint honey aroma observed; further extractions with diethyl ether give little.
Conclusion and future directions: this setup did not reduce mandelic acid under these conditions; potential improvements include different solvent, adjusting water content, catalytic hydroiodic acid, or other tweaks; the result is a cliffhanger; more experiments planned.
Closing note: prior related work shows aluminium/iodine can form alkyl iodides and that this line of inquiry may bear fruit with refined conditions.