Lab Report - Oxidation of 9-fluorenol to 9-Fluorenone PDF

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Summary

Lab for organic Chemistry ii ...

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Experiment Title: Oxidation of 9-Flourenol to 9-Flourenone Date (of performed experiments): 10/04/2017 Goals: In this experiment, the secondary alcohol 9-flourenol will be converted to 9-flourenone using hypochlorous acid as an oxidizing agent. Overall Chemical Equation:

Reaction Mechanism:.

+

+

+

OCl-

+ H2O

+ H2O

H3O+ + Cl- +

Procedure: 

1.5g of 9-flourenol, 10mL of acetone, and 5mL of glacial acetic acid were added to 125mL Erlenmeyer flask with a magnetic stir bar



The solution was then heated and stirred to dissolve the alcohol



Once dissolved, the solution was allowed to returned to room temperature



21 mL of bleach was added at 2mL/per minute



The solution was then transferred to a separatory funnel and washed with 20 mL of methylene chloride



The solution was then shaken to separate the aqueous and organic layer



The organic layer was then reserved in a beaker



The aqueous layer was then washed with 10mL methylene chloride



The organic layer from this solution was reserved with the other



The combined organic layers were then washed with 20.0mL sodium bicarbonate and vented



The aqueous layer was then removed



The organic layer was washed with 15mL of distilled water



The organic layer was transferred to a 125mL Flask and dried with anhydrous sodium sulfate and decanted



The solution was then evaporated for a week leaving the dried product



The mass, IR, NMR, and MP were collected

Observations: 

Solution had a yellow-orange chunky presence when stirring



Separation occurred all at once



Solution was not recrystallized

Results: TLC plates:

Calculations: Theoretical

1.5086g 9-flourenol(1 mol 9-flourenol/182.22g 9-flourenol)(1mol 9-flourenone/1 mol 9-flourenol)

yield Experimental

(180.206g 9-flourenone/1mol 9-flourenone)= 1.49g 9-flourenone sample with beaker=52.0404g

yield

beaker=50.4099g

Percent yield

Mass of Sample=1.6305 g (1.6305/1.49)=1.09%

MP: Melting Point

130135C

Spectroscopic Analysis: Infrared

There is evidence of a C=O bond, a peak at ~1700cm-1. There is also an absence of peaks to the right of 3000cm-1 meaning there are no sp3 hybridized C—H bonds. The woobles at ~2000cm-1 and peaks at ~1600cm-1 and ~1500 are indicative of a benzene ring.

Spectroscopic Analysis: NMR

This H-NMR indicates 4 sets of chemically equivalent hydrogens. There is evidence of a benzene shift at ~7ppm.

Discussion: This reaction can be classified as an oxidation because in an oxidation reaction, a molecule, atom, or ion loses electrons. Additionally, oxidation is known as gaining an oxygen or losing a hydrogen. Typical oxidizing agents include chromic acid, PCC, and hypochlorous acid. When secondary alcohols undergo oxidization with these reagents they yield ketones. When primary alcohols undergo oxidation using PCC or hypochlorous acid they are oxidized to aldehydes. When primary alcohols undergo oxidation using chromic acid they are further oxidized from a aldehyde to a carboxylic acid. Tertiary alcohols cannot be oxidized to a carbonyl C=O group because the alpha carbon bonded to the OH is not bonded to a hydrogen. Green chemistry works to use less harmful reagents. Specifically, in alcohol synthesis, solid-supported reagents are used—the polymeric resins are harmless and can be reused in further oxidations. An example of a green reagent is bleach, bleach contains the hypochlorite ion. Bleach is less environmentally harmful than traditional oxidizing agents. Overall, our TLC was unusable. The data acquired from it showed no clear spots, but was instead covered in a plethora of spots. The goal of TLC was to monitor the reaction and match the products to the standards. The melting range of the product was 130C-135C. In this, the melting point indicates that 9-flourenone was not the product. 9flourenone has a melting range of 80C-83C. The H-NMR spectra is not indicative of 9-flourenone. The spectra that is expected from 9-flourenone would have 2 sets of chemically equivalent hydrogens with an integration of 1:1. The H-NMR is indicative of an impure product. In the spectra collected, there appears to be an alcohol shift at ~2.5ppm. IR could be

indicative of 9-flourenone, there is evidence of a C=O, a benzene ring, and an absence of sp3 C—H bonds. In this, the product synthesized may be a mixture of alcohol, ketone, and unknowns. Error in this experiment was present in the high-percent yield as well as the H-NMR spectra. The percent yield being above 100% indicates the impurity of the product. The H-NMR spectra’s odd integration as well as the low resolution of the peaks brings error. Because of the conflicting evidence that is present in this experiment, the most effective way to rectify this error would be to redo the experiment. Additional trials could be done to confirm results.

Conclusion: Overall, the IR spectra alone is not enough evidence to conclude that 9-flourenone was successfully synthesized. The high percent yield also indicates that the product was impure. In this, the goal of the experiment, to convert the secondary alcohol 9-flourenol to 9-flourenone using hypochlorous acid as an oxidizing agent cannot be confirmed. Because of the conflicting data was acquired, the experiment should be repeated.

References: Analytical, Biology, Chemistry & Materials Science products and services. http://www.sigmaaldrich.com/ (accessed Oct 2 2017). Bruice, P Y. Organic Chemistry. Vol. 7, 2014. Mohrig, Jerry R., et al. Laboratory Techniques in Organic Chemistry: Supporting Inquiry-Driven Experiments. 4th ed., W.H.Freeman, 2014....