Lab 9 Applied Observations of Functional Groups Fall

Lab 9: Applied Observations of Functional Groups Fall 2018 Chemistry 1331: Chemical Structures and Properties Tues. Oct. 30 - Mon. Nov. 5

Background Functional Groups in Biology 1) Porphyrin Functional Groups and Solvent Polarity 2) Solvatochromism

Pre-Lab • Any Questions? • Take 5/10 minutes to take the pre-lab

A little out of order…. • Let’s get this started… • Combine • 10 m. L Propionic Acid • 0. 12 m. L Benzaldehyde • 0. 08 m. L Pyyrole • Heat to Reflux for 30 minutes

Functional Groups

Porphyrin Synthesis Soret band = ~ 400 nm e = ~10 5 (intense)

Solvatochromism • Reichardt’s dye changes color in solutions as a function of polarity. • We will measure the lmax • Compute: ET(30) = 28591 / lmax The ET(30) is a proxy for polarity measurement.

UV-Vis • lmax is the wavelength (in nm) of largest absorbance peak in the spectrum

Procedure • #1 Synthesis of TPP • Combine • 10 m. L Propionic Acid • 0. 12 m. L Benzaldehyde • • • #2 Reichardt’s Dye • 0. 08 m. L Pyyrole Heat to Reflux for 30 minutes Add small portions of cold Methanol Filter to isolate product • • Take approximately 5 m. L of each of the following solvents • Methanol • Ethanol • 1 -Propanol • 1 -Pentanol • Acetone Add a few drops of Reichardt’s dye solution Measure the lmax

Next Week • For Next week. • Read Lab #10, be prepared to discuss.