preview

Microwave-Assisted Suzuki Synthesis Lab Report

Better Essays
Microwave-Assisted Suzuki-Miyaura Coupling Beginning Question: How effectively and efficiently can biphenyl be synthesized by a Suzuki coupling reaction? Claims: Biphenyl synthesized by a Suzuki coupling reaction was effectively isolated and then characterized using TLC, melting point, IR and 1H NMR tests. However, this process was not efficient because it had a poor pure yield of 22%. Evidence: The goal of the experiment was to synthesize biphenyl product by a Microwave-assisted Suzuki reaction and this was carried out using 1 equivalent bromobenzene, 1 equivalent phenylboronic acid, 1.3 x 10-2 equivalent Pd(OAc)2, 3.0 equivalent Na2CO3, and 0.25 equivalent TBAB (Figure 1). All starting reagents were combined in a microwave tube and the…show more content…
We obtained a purified yield of 22% for a white, crystalline solid, which weighed 0.033 g. Then, we used deuterated-chloroform to dissolve a small amount of the reaction product for 1H NMR testing. Because we had a small amount of purified product, this required us to rotovap the 1H NMR solution so that we can reuse the remaining for IR testing as well. We added an extra IR test for isopropanol to help us analyze the IR results for the product. Melting point was measured with the plateau temperature set at 64°C, which is 5°C below biphenyl’s expected boiling point of 69°C (U.S. National Library of Medicine). The melting point for the greyish solid was determined to be 64°C. Reasoning: In the TLC, the more organic compounds, such as biphenyl and the unknown reaction product, travel further down the plate due to its lower affinity for the polar silica gel and thus had greater Rf values. On the other hand, phenylboronic acid had a very low Rf value of 0, but this was expected due to the polar nature of its two hydroxyl groups. Since the standard biphenyl and the reaction product had the most similar Rf values, this suggested that the identity of the product is most likely…show more content…
In addition, there was also an interesting peak at 3465.8 cm-1. This peak suggested the presence of an OH group, specifically maybe that of the isopropanol to clean the IR instrument. Because of this, we decided to run an extra IR for that isopropanol solution. However, the OH peaks did not seem to correlate or resemble each other. Isopropanol’s OH peak at 3326.6 cm-1 was broader and much more prominent that that of the product (Figure 4). Thus, the 3465.8 cm-1 could represent more carbon-carbon interactions, which then further supports the possibility that the product is
Get Access