Nucleophillic Substitution Lab Report
Introduction:
Nucleophillic substitution is one of the most studied reactions in organic chemistry. In class, we are learning about two of these cases: SN1 and SN2. Many other reactions in this class proceed by mechanisms that are best described as somewhat between the two extremes.
The SN2 reaction occurs in a single step. The nucleophile simultaneously attaches to the substrate as the leaving group leaves. The reaction displays second-order kinetics; its rate is proportional to the concentrations of the both the substrate and the nucleophile. In a SN1 reaction, the first step is departure of the leaving group from the substrate to form a carbocation(rate-determing); the second step the carbocation rapidly attacked by a nucleophile. …show more content…
You will use this to gently heat any reaction that does not immediately form a precipitate when the chemicals are mixed. Heat any of these reactions for 5 min and record your results. Try to time when the precipitates appear when heating them. You should also have an ice bath to slow down any reactions that go too fast.
Initial SN2 reactions: in three test tubes, place 1-2 drops of 1-bromobutane, 2-bromobutane, and 2-bromo-2methylpropane. Then add about 1 ml of 0.5M NaI in 2-butanone to each tube. Gently shake and record the time necessary for a precipitate to form. If no precipitate is formed, then gently heat for 5 min and record your results.
Initial SN1 reactions: in three test tubes, place 1-2 drops of 1-bromobutane, 2-bromobutane, and 2-bromo-2methylpropane. Then add about 1 ml of 1% AgI in ethanol to each tube. Gently shake and record the time necessary for a precipitate to form. If no precipitate is formed, then gently heat for 5 min and record your results.
Please compare your results with a few of your neighbors. Did everything line up? Did people get mixed results?
After you have completed the above reactions, you will need to complete the questions below in order to prepare …show more content…
Feel free to perform addition experiments if you have another question you wish to investigate.
Lab Notebooks and Reports:
Pre Lab:
For the pre-lab draw all the structures of the compounds above and using two different compounds, please draw out mechanisms for the SN1 and SN2 reactions. Also, next to each structure, please predict whether you think it will undergo an SN1 or SN2 mechanism or possibly both. I would suggest you actually try this on your own as I am pretty sure I am going to give you a quiz on it.
Notebook:
Your data section in your notebook should report the results for the experiments you did. For day 1, you will just need a table of results from the initial SN1/SN2 conditions. Make sure your results are neatly tabulated. For Day 2, please make sure each set of experiments is labeled with a short heading that describes what was to be accomplished, e.g., "Effect of solvent polarity on SN1 rxn rates” and the results you obtained.
Report:
You will be turning in a full lab report for this two-week lab. I expect there to be a short introduction, a fairly
Nucleophillic substitution is one of the most studied reactions in organic chemistry. In class, we are learning about two of these cases: SN1 and SN2. Many other reactions in this class proceed by mechanisms that are best described as somewhat between the two extremes.
The SN2 reaction occurs in a single step. The nucleophile simultaneously attaches to the substrate as the leaving group leaves. The reaction displays second-order kinetics; its rate is proportional to the concentrations of the both the substrate and the nucleophile. In a SN1 reaction, the first step is departure of the leaving group from the substrate to form a carbocation(rate-determing); the second step the carbocation rapidly attacked by a nucleophile. …show more content…
You will use this to gently heat any reaction that does not immediately form a precipitate when the chemicals are mixed. Heat any of these reactions for 5 min and record your results. Try to time when the precipitates appear when heating them. You should also have an ice bath to slow down any reactions that go too fast.
Initial SN2 reactions: in three test tubes, place 1-2 drops of 1-bromobutane, 2-bromobutane, and 2-bromo-2methylpropane. Then add about 1 ml of 0.5M NaI in 2-butanone to each tube. Gently shake and record the time necessary for a precipitate to form. If no precipitate is formed, then gently heat for 5 min and record your results.
Initial SN1 reactions: in three test tubes, place 1-2 drops of 1-bromobutane, 2-bromobutane, and 2-bromo-2methylpropane. Then add about 1 ml of 1% AgI in ethanol to each tube. Gently shake and record the time necessary for a precipitate to form. If no precipitate is formed, then gently heat for 5 min and record your results.
Please compare your results with a few of your neighbors. Did everything line up? Did people get mixed results?
After you have completed the above reactions, you will need to complete the questions below in order to prepare …show more content…
Feel free to perform addition experiments if you have another question you wish to investigate.
Lab Notebooks and Reports:
Pre Lab:
For the pre-lab draw all the structures of the compounds above and using two different compounds, please draw out mechanisms for the SN1 and SN2 reactions. Also, next to each structure, please predict whether you think it will undergo an SN1 or SN2 mechanism or possibly both. I would suggest you actually try this on your own as I am pretty sure I am going to give you a quiz on it.
Notebook:
Your data section in your notebook should report the results for the experiments you did. For day 1, you will just need a table of results from the initial SN1/SN2 conditions. Make sure your results are neatly tabulated. For Day 2, please make sure each set of experiments is labeled with a short heading that describes what was to be accomplished, e.g., "Effect of solvent polarity on SN1 rxn rates” and the results you obtained.
Report:
You will be turning in a full lab report for this two-week lab. I expect there to be a short introduction, a fairly