Ketone Reduction
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Ketone reduction
Object: To reduce 9-flurenone to 9-fluorenol with the use of sodium borohydride, sulfuric acid to collect a precipitate and methanol and a reflux apparatus in order to purify a recrystallized product.
Reaction:
Reagents & Products:
Compound
MW (g/mol)
Moles
Physical & Safety Data
9-fluorenol
182.22
mp. 153-154˚C. Irritant, white powder.
Ethanol
46.07
0.324
bp 78˚C, d 1.492g/mL. Flammable liquid, irritant, Dispose in non-halogenated waste bin.
Sulfuric acid
98.08
0.006
bp. 270-340˚C, d.1.84g/mL, corrosive irritant. Dispose of in non-halogenated waste bin. Concentration 3M.
Sodium borohydride
37.84
0.0946
0.0025
Solid flammable corrosive irritant dispose of in halogenated waste bin. No melting point it decomposes
9-fluorenone
180.21
0.901
0.0050
bp. 342˚C mp. 83.5˚C, irritant that may be combustible at high temperatures.
Methanol
32.04
0.247
bp. 64.7C, d. 0.791g/mL, Flammable liquid toxic, dispose of in non-halogenated waste bin.
Procedure Reference: Peter Marrs, Chem 232 Lab Manual, pp.53 (University of Victoria, BC). Spring2011.
Observations Data:
Mass of 9-fluorenol product
2.07g
Melting range of 9-fluorenol product obtained
145-150˚C
Literature value for melting range of 9-fluorenol
153-154˚C
Ir Analysis of Nujol
Wavenumber (cm-1)
Relative Intensity
Assignment and Comment
2923,2853
Very strong
sp3 C-H stretch
Strong
CH2,CH3 bending
Medium
CH3 symmetrical bending
In the Infrared spectrum obtained for the 9-fluorenol product there was a significant different from the 9-fluorenone spectrum in the fact that there was no sharp carbonyl peak around 1700 cm-1. Also there was a broad tongue shaped peak around 3550-3200cm-1 depicting an alcohol stretch in the 9-fluorenol spectrum. Also deep sharp peaks present around 3000cm-1 are in both spectra due to the Nujol reagent and should be disregarded.
The proton nmr spectra for 9-fluorenone and 9-fluorenol differ in the sense that 9-fluroenone has no chemical shifts other than a series of doublets 7-7.8ppm. 9-fluroenol however not only has proton shift activity between 7-7.8ppm but two separate doublets at 5.6 and 1.9. These doublets