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 beguile solvent system. (ii)To synthesize intoxicant from aldehyde by NaBH4 reduction. (iii)To identify the aldehyde isomer base on the melting ledgeman point of the inebriant produced. Procedure(Please cite to the comminuted instructions on acquaintance laboratory 12 handout)Physical beat TableType of substanceMolecular FormulaMolecular Weight (g/mol)Density(g/cm3)Melting Point(oC)Boiling Point(oC)HazardO-vanillinC8H8O3152.15-42.5265-266Harmful andIrritantFor all 3vanillinC8H8O3152.151.05680-81285isovanillinC8H8O3152.15-113-115179Vanillyl intoxicant*C8H10O3154.17-113-115--Sodium hydrated oxide**NaOH39.992.13181390CorrosiveHydrochloric acidHCl36.461.18-26110CorrosiveSodium borohydrideNaBH437.831.074505400IrritantCorrosive*Vanillyl inebriant is soluble in cold organic fertiliser solvents much(prenominal) as ether/ alcoholic drink and hot water, but insoluble in cold water. ** direction: Should not touch NaBH4 at present with skin. Result and CalculationMass of aldehyde #1 (starting material) = 0.3999 gMass of alcohol #1 (product) = 0.1573 g alcoholTheoretical put up = 0.3999 g vanillin x (154.17 g alcohol/152.15 g vanillin) = 0.4052gPercentage thing = (actual yield/theoretical yield) x 100%= 0.1573 g alcohol/ 0.4052 g alcohol = 38.8% dissolver system chosen = ethyl group acetate and hexane in 9:1 ratioMelting point hurl of alcohol #1 = 108oC -109oCObservationWhen the NaOH was added to the aldehyde #1, the ancestor turned yellowish green. It took 10 minutes for the white firm NaBH4 to completely dissolve in the aldehyde solution. When the HCl was added, the solution fizzed and bubbles came off. White precipitate formed.

After the vacuum filtration, glass white crystalline unhurt was found. DiscussionFrom the melting point take place of the alcohol 108oC -109oC, it could be goaded that the aldehyde isomer used should be vanillin, since vanillin produces vanillyl alcohol that has the melting point celestial orbit of 113 oC -115oC which is quite close to the empirical melting point range. The subtle depression could be account payable to the impurities present in the unharmed such as water. In this experiment, the vanillin is converted into vanillyl alcohol by formation of alkoxide ion, followed by protonation. The comminuted mechanism was shown below: beautiful layer... If you want to get a full essay, order it on our website: Ordercustompaper.com

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