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Methods

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  1. Delete me & place your LOGO in this area. Studying the Temperature Effect on Yield and Rate Of the Epoxidation of Cyclohexene Chris Lewis and Dr. David Oostendorp, PHD Loras College Molecular Life Science BACKGROUND MATERIALS AND METHODS RESULTS Epoxidation is a reaction that involves adding an oxygen atom across a double bond. What is unique about this reaction is that the oxygen forms a three member ring with the two carbon atoms that previously had the double bond, as well as an oxygen. Epoxides are commonly used for adhesives as well as in polymerization reactions. Numerous research shows that the rate of epoxidation can be altered by the amount of electron withdrawing groups on the peroxy acid as well as the amount of sterichindrance on the alkene (Kim, Traylor, & Perrin 1998). These effects are also seen with the shown when there are electron donation groups on the alkene (Kim, Traylor, & Perrin 1998). This study used meta-chloroperoxybenzioc acid (mCPBA) as the peroxy acid for the reaction. Epoxides have also been studied in biological systems, but more as an reaction intermediate as opposed to an product (Iyer & Harris 1993). Methods To start I ran an initial experiment using the room temperature conditions to gather a base line that I could compare the next experiments to. I used .4 g of cyclohexene dissolved in 5 ml of dichloromethane. This was reacted with 1.2 equivalents (1.01 g) of meta-chloroperoxybenzoic acid (mCPBA), which was also dissolved in dichloromethane. The mixture is then continuously stirred and the acid will precipitate out of the reaction mixture, leaving the aqueous product. To purify the product I then performed a simple distillation in order to distil away the dichloromethane solvent away from the product. The product was then put through Infrared spectrometer in order to analyse the product. Manipulation The next phase of the study involved the manipulation of the temperature in order to compare it with the base line previously obtained. All of the same concentrations were used from the room temperature reaction. The reaction was run in an ice bath that was cooled to 5° C to isolate the cold temperature. To analyse the warm temperature the reaction was run under a hot water bath that was 40° C. I could not run a temperature much higher than this because dichloromethane boils at 40° C. All of the same purification steps and analysis steps were taken to analyse the product. After repeating the experiment 3 times under the cold and heated conditions I found that the acid precipitated quicker quicker when the reaction was run at 5° C. It took 5-10 min under the cold conditions, in comparison to the 30 min that the room temperature experiment needed. Under the hot water bath (40° C) the reaction never precipitated the acid until the reaction mixture cooled back down to room temperature. The room temperature and 5° C ice bath both gave product in good yield. The room temperature experiment produced a yield of 96% and the cold manipulation gave an average yield of 90%. After an analysis of the product from the 40° C manipulation showed that the epoxide did not form, instead an alcohol group shows after the analysis of the IR. This could be due to over attack of the cyclohexene by the mCPBA. Your caption can go here. IR reading of the epoxycyclohexane. CONCLUSIONS PURPOSE It know that the typical conditions for the epoxidation of cyclohexene call for the reaction to be run at room temperature. The purpose of this study is to understand the effect that the temperature will have on the yield and rate of the reaction under hot and cold conditions. I manipulated the temperature while keeping the concentration constant in order isolate temperature as the dependant variable. After concluding this study I found that the temperature did have an effect on the rate of reaction as well as the yield. The reaction run at 5 ° C did take a less amount of time with a very similar yield. One issue that the manipulation at 40° C had is that the dichloromethane solvent did start to boil during the reaction. The room temperature experiment did produce the best yield even though it took 30 minutes. It was also the easiest of the experiments to conduct. Your caption can go here. Your caption can go here. REFERENCES Reaction Reaction showing the meta-chloroperoxybenzoic acid attack on cyclohexene to produce epoxycyclohexane. • Kim, C., Traylor, T., & Perrin, C. (1998). Mcpba epoxidation of alkenes: Reinvestigation of correlation between rate and ionization potential. Journal of the American Chemical Society, 129(37), 9513-9516. • Iyer, R., & Harris,T.(1993). Preparation of aflatoxin B 8,9 epoxide usig meta-chloroperoxybenzoic acid. Chem. Res. Toxical, 6(3), 313-316.