Conclusion

Conclusion

I reduced 9-florenone through reduction with the metal hydride reagent sodium borohydride (NaBH4). we used the organic solvent methanol to suspend the 9-flouronone and added NaBH4, a weak reducing agent , to reduce the bond by attacking the carbonyl carbon atom base of the ketone group with a hydride ion. Due to the negative charge left on the oxygen (alkoxide) due to the due to reduction, the Boron (BH3) acting as a Lewis acid picks the charge forming an ionic complex ion. at this point, a very weak acid, in this case water from the hydroxylic solvent of BH4, will complete hydrolysis making secondary alcohol and the sodium borate remains suspended as soluble inorganic salts. thus, as soon as BH4 was added, 9-florenol began forming, but adding more water increased the concentration, acting as a hydroxide catalyst pushing the reaction toward the products, thus as completing the reaction as the alkoxide ion replaced boron with a hydronium ion stripped from water to form an alcohol. re crystallization was then performed to collect the 9-flourenol product by super saturating the solution on heat and crystallizing it in ice. this should leave impurities and inorganic salts in the solution which are removed by the Hirsh funnel.

the product of the reaction has been successfully identified in three ways. first, there is an obvious color change between flourenone (yellow) and flourenol (white) which was expected and observed. Second, the Rf values of the known 9-flourenol match exactly at .28 on the TLC plates. thirdly, the melting point of the product 150-158 C encompasses the melting point range expected of 9-flourenol. note, on the TLC, flourenol is more polar due to the newly added alcohol group and its hydrogen bonding capabilities, thus it was more drawn to the polar silica of the TLC plate and did not travel as far as9-flourenone. the experiment worked well and I produced 84.2% of the theoretical yield which was confirmed by the presence of flourenone in rows 4-9 of the TLC plate. I conclude that the concentration of water must have been a limiting factor in this reaction, because when rinsing the funnel, more flourenol precipitated in the beaker below.

Post lab

1) Based on the TLC, I deduce three things. firstly, the reaction occurs very quickly