Lab 12: Reduction of an Aldehyde to a Primary Alcohol by Use of NaBH4

Lab 12: Reduction of an Aldehyde to a Primary alcohol by Use of NaBH4Purpose(i)To select an appropriate solvent system. (ii)To synthesize intoxicant from aldehyde by NaBH4 reduction. (iii)To identify the aldehyde isomer based on the melting breaker headway of the inebriant produced. Procedure(Please refer to the comminuted instructions on science laboratory 12 handout)Physical Quantity TableType of substanceMolecular FormulaMolecular Weight (g/mol)Density(g/cm3)Melting Point(oC)Boiling Point(oC)HazardO-vanillinC8H8O3152.15-42.5265-266Harmful andIrritantFor alone 3vanillinC8H8O3152.151.05680-81285isovanillinC8H8O3152.15-113-115179Vanillyl alcohol*C8H10O3154.17-113-115--Sodium hydrated oxide**NaOH39.992.13181390CorrosiveHydrochloric acidHCl36.461.18-26110CorrosiveSodium borohydrideNaBH437.831.074505400IrritantCorrosive*Vanillyl alcohol is soluble in inhuman organic solvents much(prenominal) as ether/alcohol and hot water, only insoluble in cold water. **Caution: Should n ot spook NaBH4 now with skin. Result and CalculationMass of aldehyde #1 (starting material) = 0.3999 gMass of alcohol #1 (product) = 0.1573 g alcoholTheoretical contribute = 0.3999 g vanillin x (154.17 g alcohol/152.15 g vanillin) = 0.4052gPercentage topic = (actual yield/theoretical yield) x 100%= 0.1573 g alcohol/ 0.4052 g alcohol = 38.8%Solvent system chosen = ethyl acetate and hexane in 9:1 ratioMelting agitate mould of alcohol #1 = 108oC -109oCObservationWhen the NaOH was added to the aldehyde #1, the solution turned yellow-bellied green. It took 10 minutes for the white solid NaBH4 to completely disappear in the aldehyde solution. When the HCl was added, the solution fizzed and bubbles came off. White precipitate formed.

After the inanity filtration, glassed white crystalline solid was found. DiscussionFrom the melting point extend of the alcohol 108oC -109oC, it could be determined that the aldehyde isomer used should be vanillin, since vanillin produces vanillyl alcohol that has the melting point range of 113 oC -115oC which is quite shut out to the observational melting point range. The slight depression could be payable to the impurities present in the solid such as water. In this experiment, the vanillin is converted into vanillyl alcohol by formation of alkoxide ion, followed by protonation. The detailed mechanism was shown below:Thin layer... If you want to overtake a full essay, order it on our website: OrderCustomPaper.com

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