CHM 2211L Lab Report Three

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Apr 3, 2024

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Green Oxidation of Borneol to Camphor

Introduction – Oxidation reactions increase a given carbon’s oxidation state, meaning that the number of bonds that specific carbon has to oxygen or other electronegative atoms is increased. Oxidation reactions usually occur along with reduction reactions, commonly named a “redox” reaction. During the reaction, the compound being oxidized loses electrons (oxidation number increases) and gives them to the reduced compound, causing its oxidation number to decrease (Spohrer et al.). The oxidation of alcohols, specifically, can lead to different forms of aldehydes, carboxylic acids, or ketones depending on their structure (Weldegirma, 84). When oxidizing a primary alcohol with an agent such as chromic acid, Jones reagents, or PCC, the alcohol transforms into an aldehyde or carboxylic acid. Secondary alcohols, having two “R” groups, are oxidized into a ketone form. For an oxidation reaction to occur, there must be an organometallic catalyst containing either a transition metal complex or a metal center. The process also needs to occur with extra reagents and the presence of light or heat (Hosseini et al.). Some oxidants can be considered more selective than others, oxidizing primary alcohols into different forms. For example, a strong oxidant like chromic acid can oxidize propan-1-ol into propionic acid, a carboxylic acid. But a weaker, more selective oxidant like PCC can oxidize the same compound into propionaldehyde. This selectivity is not seen in secondary alcohols. The transformation of Borneol into Camphor via Oxone and catalyzed by sodium chloride and EtOAc/H 2 O is an example of an oxidation reaction using a secondary alcohol. The alcohol group and hydrogen on the molecule follow a specific mechanism to transform into a ketone. Oxidation conditions are generally harsh and environmentally harmful, with many reagents being carcinogens. Performing oxidation reactions in this way prevents the development of green

chemistry, an approach to reduce the amount of waste created by chemical reactions. Oxone (KHSO 5 ) is an oxidizing agent that is considered not only a powerful oxidizing agent but a safer alternative to harsher agents. Health and safety hazards associated with Oxone are low, yields are high, and the salts produced by the reactions are mostly harmless (Weldegirma, 85). Safe agents are important to reduce the waste output of labs, but also to protect those working in them. Mechanism of the Synthesis of Camphor – Side Reaction –

Experimental Section – Start steam bath on hot plate in 10mL round bottom flask, add 200mg Borneol Add 1mL ethyl acetate Add stir bar Weigh 0.5g Oxone Weigh 50mg NaCl Add to mix with 1mL DI water Preparation of Round Bottom Vial Set up silica plate, use 9mL hexane and 1mL EtOAc in chamber Place inside Iodine chamber Stir mixture for 30m, take TLC add 3mL of DI water and spatula of sodium bisulfate TLC of Organic Layers Test aq. layer with starch iodine paper Remove stir bar Transfer to 5mL conical vial Extract aqueous layer with 1mL ethyl acetate Combine organic layers Dry with magnesium sulfate Testing with Starch Paper After 5m, decant to weighed 25mL Erlenmeyer with a boiling stone Wash drying agent with 1mL EtOAc into flask Place flask over hot water Use compressed air to evaporate solvent, leaving a solid residue Decant and Wash Remove immediately Reweigh cool flask Determine camphor % yield Note odor, determine melting point Obtain HNMR and IR spectra Solid Residue and Spectra Analysis

Table of Chemicals – Chemical Structures— Chemical Name Chemical Structure Borneol “Endo-(1S)-1,7,7- Trimethylbicyclo[2.2.1] heptan-2- ol” Oxone “Potassium peroxysulfate” Camphor “1,7,7- Trimethylbicyclo[2.2.1]heptan-2- one” Sodium Chloride Ethyl Acetate “Ethyl ethanoate” Hexane Sodium Bisulfate “Sodium hydrogen sulfate” Magnesium Sulfate

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