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Topic: Reduction of Vanillin into Vanillyl Alcohol with Sodium Borohydride  (Read 803 times)

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SonilGomes

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As the title suggests, for class we've been asked to determine a procedure that would successfully synthesize vanillyl alcohol from vanillin using sodium borohydride. I've been glancing over example labs from various sources and I think I've got most of the procedure down so far, but I'm stuck on the solvent to mix with the vanillin. Some say ethanol is better while others say to stick with the same NaOH that you'd be using for borohydride solvent. Is there any reason why one would be better than the other?

Also: if someone could double check my math in terms of amounts, that'd be helpful. I planned on using a 1:2 ratio of vanillin to ethanol (3g and 6g, respectively) and 0.75g sodium borohydride, but I wasn't sure how much solvent to add to the borohydride. Do these numbers sound right at all?

Offline AWK

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Re: Reduction of Vanillin into Vanillyl Alcohol with Sodium Borohydride
« Reply #1 on: November 05, 2019, 07:43:32 AM »
Why are you asking about something that has long been a known procedure? Even if there are two types of procedures, there is something behind it. The idea is for the reduction to take place in solution (why in solution - for the reaction to go fairly quickly; this is quite important in alcoholic solutions because alcohol breaks down NaBH4 - fortunately quite slowly). If we reduce the water-insoluble aldehyde or ketone, you must use a water-miscible solvent (the choice is small - methanol or ethanol) in such an amount that after adding NaBH4 in NaOH (why in NaOH - because NaBH4 is relatively stable in a strongly alkaline solution). In the case of vanillin, it can be dissolved in a solution of NaOH or alcohol.
All this can be read in textbooks - sometimes between the lines, but it results from the knowledge already possessed by the reader.
AWK

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