Chem 231

The major product was determined to be the β-anomer of glucose pentaacetate, which was verified by melting range data, polarimetry, and NMR analysis. An impurity was present and can be indicated from the polarimetry data. . The derivate, triphenylmethyl methyl ether had an observed melting range of 70-85°C3. Impurities were present in the products and could be seen through the observed melting point, as well as the NMR data. The product contained impurities, as the melting range was 52-54o C1, slightly short of the literature range of 60-61o C2 for 1-(3-nitrophenyl) ethanol. Lithium aluminum hydride would be a better agent for reducing the nitro group due to the electropositive nature of lithium and the increased density near the hydrogen of the aluminum hydride, making it a better donor than sodium borohydride.

Figure 1. Silica gel tlc plate spotted from left to right with stock solution, crude phenanthrene, and recrystallized phenanthrene. The plate was dipped in bromocresol green stain to indicate the presence of the m-toluic acid for determination of the Rf values. The crude phenanthrene product had a percent recovery of 75.9, which was slightly higher than the recovered amount of the recrystallized form. The best solvent for the recrystallizing of m-toluic acid and p-bromoaniline was toluene. This is due to the fact that polar solvents, such as ethanol, are completely miscible in water.

In this experiment, a mixture of alkenes was produced with a yield of 35.32%. The maximum yield was achieved through constant distillation of the products. Following Le Chatelier’s Principle, the continuous removal of product resulted in a shift to the product (right) side in order to balance the removal of products which in turn created more product. Without distillation there would be no shift in equilibrium and less product would be produced, decreasing the overall yield. A yield of 35.32% was determined for the alkene product, which was formed through constant distillation.

...