Ketone Reduction

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) Used Moles Physical & Safety Data

9-fluorenol 182.22 - - mp. 153-154˚C. Irritant, white powder.

Ethanol 46.07 10mL 0.324 bp 78˚C, d 1.492g/mL. Flammable liquid, irritant, Dispose in non-halogenated waste bin.

Sulfuric acid 98.08 2mL 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 10mL 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

1456 Strong CH2,CH3 bending

1377 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