Preparation of 1-Chloro-1-Phenylethane

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Object: To prepare and isolate 1-chloro-1-phenylethane by refluxing 1-phenylethanol with thionyl chloride. Observations: * Solution is a clear, slightly yellow colour after addition of the thionyl chloride, prior to addition the 1-phenylethanol was clear and colourless * Small bubbles formed upon the slow addition of thionyl chloride through the top of the condenser * As time progressed with gentle reflux the yellow became slightly darker in colour * Lots of bubbles forming in the solution with 5 min left of refluxing * The product formed after reflux was a light brown/beige colour * As the quenching occurred the product became cloudy * After quenching visible separation of organic in the form of bubbles floating throughout the solution * The product was washed with ether forming an aqueous layer and an organic layer * The organic layer was then washed with sodium bicarbonate also producing 2 separate layers * Evaporation of ether was visible in the rotovap until a quarter sized amount of solution was left. Discussion The bubbles that were formed upon the addition of the thionyl chloride are due to the reaction of the two reagents. HCl and SO2 gas accounts for the bubbles formed in the beginning of the reaction. Similarly this can explain the excessive amount of bubbles formed at the end of the refluxing. It is difficult to determine which one of the gasses comes first. The mechanism in Diagram 1 indicates that the HCl would be first but does not indicate a time period. If the initial intermediate reacted quickly enough then the secondary intermediate would definitely contribute to the bubbles formed (SO2). A way to test for this would be to collect the initial gas given off by the system and use gas chromatography to identify the gas. As well a test of the solution using HPLC would help to discover if any intermediates

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