Lab G: A Reduction Reaction: Synthesis of Vanillyl Alcohol

scheme (draw it)

check

where is vanillin used?

what is NaBH4 good for? does NaBH4 react slowly with water:

what is the solvent for the reaction?

how does excess NaBH4 react wit HCl?

vanillin used in vanilla extract

NaBH4 used as a good source of H+ ions. this H+ is a good nucleophile towards carbonyl group. NaBH4 reacts slowly with water so it only reduces aldehydes and ketones (not other functional groups)

solvent is NaOH

NaBH4 (aq) + HCl (aq) + 3H2O(l) → NaCl(aq) + H3BO3 (aq) + 4H2 (g)

procedure

what happens after you add HCl?

solid vanillin dissolved in NaOH with stir bar→put in ice bath WHY IS IT IN AN ICEBATH?

add NaBH4 while stirring

remove from ice bath and let sit

slowly add HCl via pipette. solution will be slightly acidic (pH paper will be pink). solution will precipitate out and H2 gas will form

vacuum filter using water

mix a small amount with acetone to dissolve it and do TLC

TLC solution: 4:6 ethyl acetate:hexanes

waste disposal:

what do you do with the vacuum filtrate?

what do you do with the TLC development solution?

filtrate from vacuum goes to “aqueous water container”

TLC development solution goes to CHO non-halogenated