Conversion of Alcohols to Alkyl Halides
Ankita Patel
August 6, 2013

Introduction This lab consisted of the conversion of alcohols into alkyl halides through common substitution methods. These methods include SN1 and SN2 mechanism, both of which can occur for this type of reaction. For both reactions, the first step of protonation will be to add hydrogen to the –OH group and then the rest of the reaction will proceed according to the type of mechanism. SN1 reactions form a cation intermediate once the H2O group leaves, then allowing a halide (such as Br) to attack the positively charged reagent1. On the other hand, SN2 reactions are one-step mechanism in which no intermediate is formed and the halide attaches as the leaving …show more content…

This NMR analysis confirmed that this reaction did indeed go through a SN2 mechanism.
Figure 3: IR of 2-pentanol
The IR from 2-pentanol showed that the reaction went to completion because the alcohol absorption was gone. The alcohol stretch would have been a very broad peak around 3400cm-1. In this IR, one can see the C-H sp3 around 2940cm-1. The important thing to get from this IR is the fact that the reaction went to completion and does not contain the starting material. Further analysis of this reaction was done by NMR to determine the actual shape of the product.
A
A
B
B

+
A
A
B
B

Figure 3: NMR of 2-pentanol The results of the NMR of 2-pentanol showed that there was indeed a mixture of products. One can tell this because of the integration at peaks A and B. Figure 5, below, shows these peaks in a closer view. It would be hard to determine exactly which of the products it is based on this NMR. The peaks located closer to 1.0 ppm are almost hard to distinguish. One can make those peaks match either of the products, but it would be hard to distinguish which of the products it is exactly. Thus, this reaction went through an SN1 mechanism because of the rearrangement and the mixture of the products. A= 2-bromopentane B= 3-bromopentane

B
B
A
A

Figure