Ramblings of the QuASI

These are the discussion questions to go with the QuASI REEL lab report due next week. Its some food for thought.  Ill post my idea/thoughts/responses to each of these sometime in the next week.  I need to really do some research first to get all my facts straight.

Discussion Questions ¹

1. The synthesis of these new azo dyes using a procedure adapted from methyl orange was not as easy as it sounds. The solubility of the starting materials we a big issue. What steps would you take to modify the procedure to overcome some of your synthetic difficulties and the uncertainty that resulted?

2. Some of the compounds that were tested were recrystallized and some were not. Why could this be a problem? Why doesn’t Dr. Paul care if what we tested was pure or not? On the other hand, discuss the benefits of working with pure molecules?

3. The “A” in QuASI is for “aqueous”, and some of your products were not soluble enough in water to analyze their properties. Propose changes to the dye molecules structure that might make them more soluble in water without affecting their ability to detect anions.

4. Anions are extremely soluble in water because water strongly hydrogen bonds to these atoms to stabilize their concentrated charges. Would you expect complexing/associating an anion with an organic molecule would be difficult in the presence of so much water? What would you have to do to make your dye molecule a better “life raft” or “seat cushion” for the halides to sit down on?

5. Why would you expect a halide to change the color of an organic molecule in solution?

6. A majority of the UV‐vis analysis studies did not record a significant change in λmax between chloride and bromide containing solutions, yet this may not be a problem with our hypothesis. Consider as many aspects of the experiment that might factor into this negative result. Why did so many people see no change?

References:

(1) Paul, Noel. "Anion Selective Indicator (QuASI) for Aqueous Solutions." Chemistry 255 Research Experience to Enhance Learning. (2011): Print.

Schedule for the week

This weeks schedule:

1.  Long day of lab and lectures on Monday.  In class until 8:30 PM (no fun!).

2. Meet with Dad for lunch on Tuesday.  He’s in town to interview a few candidates for a job opening at his place of employment.

3.  Work a couple all nighters finishing up the REEL QuASI lab report that I’ve mentioned.  Hopefully I can make sense of it all.  The unfortunate thing is It has to be turned in Wednesday because…

4.  Thursday through Sunday I will be in Indianapolis for the Women's Basketball Big Ten Tournament.  The Buckeyes have a first round bye so I may not leave till Thursday night since there first game isn't until ~8pm Friday night.

 

Benzocaine

In chemistry class we were asked a concept question on why the addiction of p-aminobenzoic aid and 95% ethanol in the presence of an acid catalyst prefers to form benzocaine instead of poly(4-aminobenzamide).  I made two mechanisms about the Fischer esterification process going on but not sure if its correct.

References:

(1) Callam, Christopher; Paul, Noel M.: Synthesis of Aspirin. Organic Chemistry Lab- Chemistry 255; McGraw-Hill: New York, 2009; pp 109-129.

(2) Chemical Book Online Catalog. http://www.chemicalbook.com/ChemicalProductProperty_EN_CB1217951.htm

Organic Dyes

This is the Organic dye that me and my partner decided to synthesize in lab today, based on the recorded solubility in water and ethanol, as well as a few other benefits found with this particular dye.  The idea is to hopefully find a dye that reacts with anions in water so as to be able to test the concentration of potentially toxic anions by the use of a colorant.  In theory, if a certain anion is present, the dye will change colors to reflect the recorded anion.

This formula is property of The Ohio State University Chemistry Department

References:

(1) Paul, Noel. "Anion Selective Indicator (QuASI) for Aqueous Solutions." Chemistry 255 Research Experience to Enhance Learning. (2011): Print.