Peter Defnet and Cody Krepps
Department of Chemstry
September 18, 2012
Abstract: Nitration of 2-benzylpyridine is supposed to yield 2-(2,4-Dinitrobenzyl) pyridine, when electrophilic aromatic substitution is the mechanism. Experiencing many pitfalls, however, has lead to the actual product obtained to contain the expected product, as well as many impurities. This report examines the supposed mechanism for the electrophilic substitution, a mechanism for the product’s photochromic property, as well as an explanation as to why the mechanism happens in this particular sequence.
Nitration of 2-benzylpyridine through electrophilic aromatic substitution…show more content…
Methanol was then added to the solvent in attempt to recrystallize it. However, too much solvent was added and the solid dissolved at room temperature. The solution was heated most of the solvent was removed. Still, no crystals were forming, and by recommendation, the solution was dried by nitrogen gas. The resulting solid was dried for a short period of time and an IR and melting point was taken of this new solid. The new IR better reflected the IR spectrum for the expected product, and the melting point was closer to the expected one as well. As shown on the IR, however, the melting point increase could have been exhibited by still having some methanol left with the solid product.
To determine if any 2-(2,4-Dinitrobenzyl) pyridine was obtained, the solid was allowed to sit in the sunlight for 10 minutes. Because no color change was observed, it was concluded that our product did not contain significant amounts of the expected product. The remaining solid was dissolved in ether and examined using the GC-MS. This test informed us that 60% of our product was the 2-(2,4-Dinitrobenzyl) pyridine. Other products are shown in figure 2 below.
Figure 2: Products identified by the GC-MS.
As noted above, there are many possible reasons as to why our reaction did not yield the expected product. Perhaps the most prominent error was adding too much sodium hydroxide to the icy mixture, which caused our product to never be able to form large, solid crystals. The