Cholesteroidal Ketone Lab Report

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Abstract In this experiment, cholesterol underwent four sequential reactions to convert into a conjugated steroidal ketone. Cholesterol (with hydroxyl group peak at 3408 cm-1) was oxidized into 5-cholesten-3-one (with a carbonyl group peak at 1719.4 cm-1 and an alkene at 1467.8 cm-1) through a couple of intermediate involving bromination and debromination. 5-cholesten-3- weighing 0.57 g was then isomerized into 4-cholesten-3-one (with carbonyl peak at 1676.9 cm-1 conjugated to an alkene positioned at 1617.3 cm-1). The final product had a percent yield of 19.53%. Introduction Cholesterol (C27H46O) is a major constituent of biological systems. The steroid is essentially responsible for membrane fluidity (Alberts et al., 2013). The steroid also…show more content…
It was performed at the end of the first three reactions. The process employs dissolving an impure solid in a particular solvent under heat. This is occasionally followed by the addition of decolorizing charcoal which binds to impurities. The solution is reheated, filtered by gravity, let to stand at room temperature, and subsequently submerged in an ice bath to facilitate crystallization. Filtration by suction produce a purified product that can then be analyzed using an IR spectrometer. Liquid-liquid extraction is another technique of equal significance. It utilizes a separatory funnel and separates organic compounds based on their solubility. Accordingly, an organic compound can be isolated through the aqueous or organic layer. The aqueous layer can be modified to extract certain water insoluble organic compounds in their ionic form. This is achieved by making the aqueous layer either basic or acidic, depending on the compound’s functional group characteristics. Recrystallization can then be employed to extract a desired product in its purified form. Isolated (dry) recrystallized products undergo IR spectroscopy to assess purity of organic compound and efficacy of technique. Accordingly, experimental functional group peak values are compared to literature ones obtained from the SDBS database. IR spectroscopic analysis can also identify unknown organic samples based on their functional group peaks.…show more content…
The biggest variance between experimental and literature peaks is that of C=C conferring to a difference of 154.3 cm-1. The other two peaks fluctuate around their corresponding literature values. It is not unusual for functional groups to be skewed. However, change in position suggests the sample is not as pure as anticipated. The conjugated system with the ketone can be seen on the IR spectrum (Figure 7). The sharp peak is differentiated from that of 5-cholesten-3-one by a joined C=C peak. This confirms that 5-cholesten-3-one was successfully isomerized into 4-cholesten-3-one. However, an unusual peak can be seen around 3500 cm-1 (Figure 7). The peak resembles a hydroxyl group. Cleaning the sodium chloride cell with chloroform and subsequently viewing it produced the same characteristic peak seen when cell was loaded with product. The IR spectrum of the clean cell was almost a replica of 4-cholesten-3-one, except the peaks were not elongated (Figure 8). This suggests that the cell is marked with the sample due to overuse. Therefore, cleaning the cell has little effect on the observed

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