University:
Howard University
Course:
CHEM 145 | Organic Chem Lab
Academic year:

2023
Views:

93

Pages:

2
Author:

Adelyn Ruiz

The Oxidation of Cyclohexanol Introduction: Alcohols can be oxidized to aldehydes and ketones using common oxidizing agents. Primary alcohols may be oxidized to aldehydes, and then to carboxylic acids. Secondary alcohols may be oxidized to ketones, while tertiary alcohols will not oxidize. The purpose of this lab is to synthesize cyclohexanone, which can be done by oxidation of cyclohexanol. In general, secondary alcohols may be converted readily to ketones using a variety of inorganic oxidizing agents, such as permanganate, hypochlorite, or chromate. In this experiment, the oxidizing agent is chromic acid, H2CrO4 . The chromium in chromic acid is in the + oxidation state, and three electrons are gained by the chromium to form the +3 oxidation state. Chromic acid is not stable over time and is prepared by mixing a dichromate salt, usually sodium or potassium dichromate, with sulfuric acid. The reaction of chromic acid with a secondary alcohol involves several steps, in which the oxidation state of chromium is changed from +6 to +3, but the slowest step involves the decomposition of a chromate ester of the alcohol to give the ketone. In this experiment, cyclohexanol is the secondary alcohol which is oxidized to cyclohexanone. After the reaction takes place, cyclohexanone is isolated from the reaction mixture which also contains chromium salts and unreacted sulfuric acid. Table1. Physical and Chemical Properties of Chemicals Used Throughout the Experiment Compound Molecular Formula Molecular Weight (g/mol) Density (g/mL) Melting Point (°C) Boiling Point (°C) Cyclohexanol C6H12O 100 0 25 161 Cyclohexanone C6H10O 98 0 -31 156 Results: Weight of cyclohexanol 6 Moles of cyclohexanol 0 moles Theoretical yield of cyclohexanone 0 moles Theoretical yield of cyclohexanone 5 g Actual yield of cyclohexanone 1 Percent yield of cyclohexanone 33% Calculations: Volume of cyclohexanone collected: 2 Density of cyclohexanone: 0/mL Weight of cyclohexanone: 0 x 2 = 1 No. of moles of cyclohexanol n = 6g/100 g/mol = 0. Theoretical yield of cyclohexanone: m = 0 x 98 = 5. Percentage yield of cyclohexanone: % yield = 1.995/5 = 33% Conclusion: Due to the presence of the strong, stake-shaped band at 1709 cm-1, cyclohexanone was successfully synthesized, however, the low yield of 33% can be attributed to the incomplete isolation of cyclohexanone.

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