Results and Discussion:

calculate the % Yield, I needed to calculate the theoretical yield first. We started the experiment by having a 3.0 g of Pinacol. I first converted the mass in grams of Pinacol to moles. In getting the moles, I divided the mass of the Pinacol (3.0g) by the molar mass of Pinacol (118.2 g/mol) and got 0.025 mols as answer. Then I calculated the theoretical yield by multiplying the number of moles (0.025mol) by the molar mass of the Pinacolone (100.16 g/mol) then dividing by the number of moles of Pinacolone (1mol) and got 2.542g as the theoretical yield. After getting the theoretical yield, I was able to calculate the % yield. I calculated the % yield by dividing the actual yield (experimental) by the theoretical yield and got that the % yield is 67.584%.

When doing the 2,4-DNP test , we saw that the color changed to an Orange solution which tells us about the Ketone presence.

When studying the IR for both the Pinacol and the Pinacolone, we see that in the Pinacol there is a peak at 3382.46 cm-1 which represent the hydroxyl group. In the Pinacolone IR we see that there is no hydroxyl peak as in Pincol but there is another peak at 2967.54 cm-1 which represents the ketone group (C=O).

When looking at the NMR for both the Pinacol and the Pinacolone, we see that the pinacol has 2 peaks; one around 1.3 ppm and the other one is around 2 ppm. These two peaks have a ratio od 12:1.9. On the other hand, the Pinacolone has two peaks that are around 1.2 ppm and 2.1 ppm and has a ratio of 9:3.0.

In this experiment, we studied the reaction of rearranging the Pinacol and getting the Pinacolone using strong acid (Sulfuric acid) and heat that will complete the reaction and make it faster. With the presence of Sulfuric acid and the fact that the penacol is 1,2-diol, rearrangement will occur and one of the hydroxyl groups will be protonated by the sulfuric acid. By that, the hydroxyl becomes a good leaving group that will lead to having a dehydration reaction. When the water goes out, we will get a tertiary carbocation that will lead to having an alkyl shift and more stable carbocation. Having a more stable carbocation is because of the resonance. Losing protons is the way that will give us the Pinacolone that contains the ketone.

We used the tap water bath because this is an exothermic reaction and there is heat released and we needed to cool it down to room temperature. We used the boiling chips in this reaction to avoid any explosion that may happen because of the heat. Distilling the water and the Pinacolone using simple distillation leads to having the reaction toward the products. According to Raoult’s law for immiscible liquids, we distill the liquids below the boiling point. That’s why the distillation stopped at 100 C because both the water and the pinacolone have a boiling point around 100 C. These two liquids were separated using transfer pipet. We distinguish between the water and the Pinacolone usinfg the density. That’s why water is on the bottom and the Pinacolone is on top. To remove what is remaining from the water after removing the aqueous layer, we added unhydrous sodium sulfate. This step is very important in getting correct IRs. After that the 2,4-DNP test was done for us to check the product. In this test we got an orange solution after mixing the product with 2,4-DNP.

When calculated the %Yield we got that 67.584% of the product were lost because of human error. The error happened maybe because of a calculation error, transferring liquids, or inaccurate measurements.

To determine how good is the Pinacolone , we used the IR technique. We saw that in the Pinacol we found a peak of the hydroxyl group that was not in the Pinacolone IR.

NMR is another way of determining the resultant product we got. The NMR is related to the number of protons the compound has. When we looked at the NMR of Pinacol, we saw that it has two singlet peaks that has a ration of 12:1.9. The first peak from the right shows a shielded methyl group whereas the other one is a de-shielded downfield shift. On the other hand, the pinacolone showed two singlet peaks that has a ratio of 9:3.0. The one of the right showed 9 hydrogens whereas the one on the left shows a de-shielded one.

At the end, this experiment was done correctly and we were able to rearrange the Pinacol to Pinacolone. We got some impurity in 67% yield.