Synthesizing Compounds

This week I focused on organic chemistry with in the lab, as we worked to synthesize complex organic molecules. Through helping to perform many reactions in order to eventually achieve our desired product, I have learned many incredible techniques that I would not have been exposed to in a high school lab.

A common technique that we use is Thin Layer Chromatography (TLC), which allows us to get a general idea of the functional groups that are in our solution. In this we carefully spot small glass plates with our product and then place them in an eluant which will carry the up the plate based on polarity and the intermolecular forces of attraction that can be formed. Through this we can get an idea of which test tubes contain our desired product.

After performing a reaction, there are many extra solvents, so to concentrate our product we often use a rotary evaporator, which through distillation, allows us to evaporate off the organic solvents. It is normally used under vacuum, while simultaneously heating the solution. The vapor evaporates off of the solution, then condenses on a container filled with ice and drips into a large, round bottom flask.

Finally, we use an HNMR (Nuclear Magnetic Resonance) Spectrometer to determine the structure of our compound. In school we learned how this machine works and how to read the data that it produces, so it was especially exciting to apply the knowledge that I had gained in school to real life research. The HNMR provides information on the chemical environments of the hydrogens within the molecule as it measures the spin states of the nuclei when they are placed in a magnetic field. The difference in energy between the parallel and antiparallel environments of the proton is representative of the chemical environments of the hydrogens and causes a subsequent chemical shift that is relative to the standard, tetramethylsilane. The HNMR provides an accurate way to compare our synthesized product to the desired product, and is therefore extremely important in our organic chemistry lab.

Citations

Rotary Evaporator (Rotovap) http://www.dartmouth.edu/~welderco/Rotovap/ (accessed July 5, 2017)

Bylikin, Sergey; Horner, Gary; Murphy, Brian; Tarcy, David Chemistry IB Diploma Program; Oxford University Press: Oxford, 2014.