Sodium Borohydride Reduction Of Vanillin Essay

Words: 540
Pages: 3

Experiment 1
Sodium Borohydride Reduction of Vanillin: A Low Solvent Synthesis of Vanillyl Alcohol
Reaction Scheme

Methods and Materials First, the TCL plate was outlined and set up to spot. 0.26g of vanillin were placed into a large test tube, followed by 1mL of ethanol and stirred until fully dissolved. The mixture was then spotted on the TLC plate. As the test tube cooled in the ice water bath, the amount of sodium borohydride was calculated based off the given stoichiometry; the amount came out to be 0.07g of sodium borohydride, which was then added to the test tube. The test tube content was stirred for 10 minutes in the bath, then taken out to warm for 5 minutes, and then put back into the bath. This mixture was then spotted onto
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Ultimately, the melting point would show the purity of the final product.
During the experiment, when the HCl was added to the test tube, an exothermic reaction occurred releasing hydrogen gas into the air. As the crystals formed in the test tube, the solid was a white color, but when it went through the vacuum filtration to dry it turned a light beige color.
The results from the experiment showed that the final product was really pure. The observed melting point was 109°C-115°C and the ideal melting point was 110°C-117°C. If a lower melting point was observed then the crystals did not dry fully and water was still present, contaminating the product. The percent yield was very low at 3.84%. This could have been a result of the crystals being very fine and slipping through the filter paper with the solution. On the TLC plate the starting material had one dot with an Rf value of 0.67, the co-spot had two dots with Rf values of 0.64 and 0.44, and the reaction product had a Rf value of 0.4. This shows that there were no contaminants because the starting material and final product both had one dot, while the co-spot had two dots, roughly matching the starting material’s and final product’s. The best way to improve this lab, and any lab to fully check the results, is to perform more