Disperse Red 9 Lab Report
Discussion:
The two dyes identified were disperse blue 3 and disperse red 9. Disperse red 9 separated first because it is less polar than disperse blue 3. This is due to the structure of disperse red 9 being more symmetrical than that of disperse blue 3 and having more nonpolar bonds. Disperse blue 3 is more polar because it has a hydroxide bond and has a larger dipole. The principle behind using column chromatography is that it separates compounds based on polarity. The alumina serves to allow for a purer separation than TLC plates because it has a more polar surface than silica gel does. The less polar dye moves first because it is not as soluble in the stationary phase as the more polar dye is. The solvent was switched from methylene chloride
to acetone to remove the more polar dye because the the more polar dye would not move through the stationary phase using methylene chloride because it was not polar enough to be soluble with the dye. Using TLC, the unknown dyes were identified by comparing the distance each dye in the mixture travelled to the distances that different standard dyes travelled. The identity of the dyes were found using mass spectrometry by comparing the m/z value of the molecular ion peak to the molecular weight of the known standards. Using column chromatography was not completely successful because spotting the less and more polar dyes resulted in two spots each. This is because it was hard to determine when once dye was done travelling through the column and when the next dye started to. This caused the vial containing the less polar dye to have a small amount of the more polar dye in it.
Conclusion:
In this experiment thin layer chromatography, column chromatography, and mass spectrometry techniques were successfully performed. When using each technique, both dyes in the unknown mixture were separated and were able to be identified.
The two dyes identified were disperse blue 3 and disperse red 9. Disperse red 9 separated first because it is less polar than disperse blue 3. This is due to the structure of disperse red 9 being more symmetrical than that of disperse blue 3 and having more nonpolar bonds. Disperse blue 3 is more polar because it has a hydroxide bond and has a larger dipole. The principle behind using column chromatography is that it separates compounds based on polarity. The alumina serves to allow for a purer separation than TLC plates because it has a more polar surface than silica gel does. The less polar dye moves first because it is not as soluble in the stationary phase as the more polar dye is. The solvent was switched from methylene chloride
to acetone to remove the more polar dye because the the more polar dye would not move through the stationary phase using methylene chloride because it was not polar enough to be soluble with the dye. Using TLC, the unknown dyes were identified by comparing the distance each dye in the mixture travelled to the distances that different standard dyes travelled. The identity of the dyes were found using mass spectrometry by comparing the m/z value of the molecular ion peak to the molecular weight of the known standards. Using column chromatography was not completely successful because spotting the less and more polar dyes resulted in two spots each. This is because it was hard to determine when once dye was done travelling through the column and when the next dye started to. This caused the vial containing the less polar dye to have a small amount of the more polar dye in it.
Conclusion:
In this experiment thin layer chromatography, column chromatography, and mass spectrometry techniques were successfully performed. When using each technique, both dyes in the unknown mixture were separated and were able to be identified.