Lab 8 Friedel-Crafts Acylation of m-Xylene with Pthalic Anhydride

Lab 8 Friedel-Crafts Acylation of m-Xylene with Pthalic Anhydride

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Lab 8: Friedel-Crafts Acylation of m- Xylene with Pthalic Anhydride Introduction: Essentially, we will demonstrate acylation by electrophilic aromatic substitution. Main Reactions:
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Procedure: To begin this experiment lab assistant Don Shipp provided us with 2.04g of anhydrous aluminum chloride in a screw cap vial. We assembled our apparatus and utilized a 25.0 mL round bottom flask as our collection container which we had equipped with a stir bar prior to utilization. We ensured that the dry reflux condenser and glass stopper were clean by having rinsed them out with acetone and vacuum dried them prior to assembly. At this point we placed 1.02 g of Pthalic anhydride and 6.0mL of m- Xylene in the flask and over ambitiously added the anhydrous aluminum chloride without having first cooled the mixture first. Not only did we add the m -Xylene without cooling the primary mixture but, we also added the m -Xylene in one fast pour. The manual indicated that after having cooled the solution the m -Xylene should have been added in small portions. This was the first large mistake we made in this experiment. We realized that gas had already begun to evolve and our reaction had started. We panicked and did not know what to do, but we figured that even if the reaction had started a little early it would not affect our end results. Little did we know that the reaction had progressed to a good extent. As we were deciding what to do as the gas was escaping I felt the flask and felt it getting slightly warm in addition to having noticed a color change of the solution from pale yellow to a deeper yellow. This clearly indicated to us that we had prematurely and sloppily begun our reaction under the wrong conditions. We decided to keep going and immersed our flask into an ice bath and allowed our solution to cool to 3 degrees centigrade. In retrospect with the gift of hindsight, I realize that there was no point in cooling the solution since we had already begun the experiment. Regardless of this inconsistency with the procedure we removed the flask from the bath and allowed it to equilibrate its temperature back to room temperature and moved on to the next step. Ignorantly assuming that the observations of our uncontrolled experiment was
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Lab 8 Friedel-Crafts Acylation of m-Xylene with Pthalic Anhydride

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