| Tripeptide Synthesis
Organic Synthesis December 8, 2004  |
The purpose of this synthesis was to synthesize a tripeptide. Using any combination of peptides, the tripeptide was produced. In this reaction, L-isoleucine, L-valine, and L-alanine were the peptides. If the goal is to synthesize one dipeptide with one distinctive order, it becomes necessary to protect the ends of the reacting peptides to prevent them from forming a solution of a mixture of different dipeptides. The DCC coupling method was used. This reaction requires that dicyclohexylcarbodiimide (DCC) be used. In this reaction, the carboxylic acid of one of the peptides reacts with the DCC to form a reactive acylating agent. The amine of the other peptide can then attack the acylating agent. This forms a tetrahedral intermediate, which sheds the dicyclohexylurea and gives the amide bond. In order to remove the Boc protection group, a treatment with an acid most often trifluoric acid will be used. The methyl ester is removed by a basic hydrolysis of base and water.
This reaction was supposed to synthesize isoleucine-alanine-valine. The purity and structure of the end product can be determined from the melting point as well as the spectral data. However, it was found that the dipeptide alanine-valine was synthesized instead of the tripeptide.
Tripeptide Synthesis |
| Gravimetric Analysis
Analytical Chemistry April 27, 2004  |
The purpose of this experiment was to determine the optimum formation conditions for forming an aluminum complex of tris(8-hydroxyquinoline) aluminum. In order to find the optimum conditions for the metal complex formation, a single condition was varied; and, during this experiment, the variable was temperature. Using three different temperature ranges, the experiment tested whether each temperature range would increase the complex's yield. It was found during the experiment that the optimum temperature range for the maximum yield of aluminum was between 60 and 70 C. It was at this temperature range that the highest percent yield of aluminum was found.
Gravimetric Analysis: Analyzing the effects of temperature upon the yield of aluminum complex |
| Multistep Synthesis
Organic Chemistry March 25 - April 8, 2004  |
The purpose of this lab experiment was to synthesize tetraphenylcyclopentadienone through a series of three different synthesis. The first step yielded benzoin from an condensation of benzaldehyde, resulting in a 44.79% yield and a melting point of 135 °C. The second step was the oxidation of benzoin to benzil, producing a yield at 30.11% yield and 92 °C melting point. The last step synthesized tetraphenylcyclopentadienone using the benzil produced in the second step, yielding at 72.78% yield and 216 °C.
Multistep Synthesis of Tetraphenylcyclopentadienone |
| Water Analysis
General Chemistry Kim Dinh, Laura Keslar, Kim Le, Maria Lizarrago April 3, 2003  |
The main objective of this experiment was to test the water quality, or water hardness, of several tap water samples. In order to determine the quality of the water samples in terms of the divalent metal ions, specifically Ca2+, two techniques were used: (Part A) complexometric titration and (Part B) ion-selective electrodes. The average molarity for the chemistry lab fountain, Part A was 3.2e-2 M (1297 ppm) and Part B was 4.64 M; for Kim Le's kitchen water, Part A was 1.9e-3 M and Part B was 1.14e-4 M. For Yuma tap water, the average molarity was 6.6E-03 and 2.73E-03 for part A and B, respectively. For Coconino, part A was not performed, but part B yielded a result of an average molarity of 1.50E-03. For Maricopa, the average molarities were 3.01E-03 and 2.52E-04 for part A and B, respectively. Gila Bend's tap water's average molarites came out to be 1.87E-03 and 1.02E-03 for parts A and B, respectively. Therefore the water with the softest water hardness was the tap water from Kim's kitchen sink and the on with the highest water hardness is from Yuma.
Analysis of Arizona water |
| Ascorbic acid content
General Chemistry April 27, 2004  |
In order to determine the time and method of cooking a vegetable so that it maintains the most Vitamin C, an oxidation-reduction titration was performed to find the concentration of ascorbic acid within six different broccoli juice solutions. The juice from the broccoli soaked for five and ten minutes maintained the lowest concentration of ascorbic acid (2.94 x 10-7 M ±2.83 x 10-9 and 4.68 x 10-7 ±2.12 x 10-8, respectively). Cooking the broccoli on the stove for five and ten minutes released the most Vitamin C into the water (7.58 x 10-5 ±1.06 x 10-6 and 1.37 x 10-4 ±0, respectively). Microwaving caused the five-minute sample to release 8.10 x 10-7 ±8.49 x 10-9 and the ten-minute sample to release 9.51 x 10-7 ±2.89 x 10-8. The healthiest preparation for broccoli would be to leave it uncooked or cooked for a minimum amount of time.
Main Presentation of Ascorbic Acid Content in Broccoli [in .ppt format] Conclusion of Ascorbic Acid Content in Broccoli [in .ppt format] |