Synthesis of cis-Norbornene-5,6-endo-Dicarboxylic Acid Lab Report

Synthesis of cis-Norbornene-5,6-endo-Dicarboxylic Acid I. Abstract The objective of experiment 48.3 was to heat cis-Norbornene-5,6-endodicarboxylic anhydride, the product obtained in experiment 48.2, in water to hydrolyze the anhydride to form cis-Norbornene-5,6-endo-dicarboxylic acid. For this experiment, 0.199g of cis-Norbornene-5,6-endo-dicarboxylic acid was collected as white crystals, amounting to a 92 percent yield. II. Introduction 1. It is difficult to take the melting point of the dicarboxylic acid as it reacts on heating. What is the likely product that is formed on heating? The reactions that occur while the dicarboxylic acid is heating are dependent upon the chain length that separates the carboxyl groups. Cyclization to form a cyclic anhydride is the most likely product that is reformed, along with water being split out. Finally, the melting point depends on the rate at which the mixture is heated. 2. cis-norbornene-5,6-endo-dicarboxylic anhydride is insoluble in water and during heating formed globules at the bottom of the reaction tube. Would stirring these globules to break them into smaller globules have sped up the reaction? Why or why not? Since cis-Norbornene-5,6-endo-dicarboxylic anhydride is insoluble in water, stirring the globules at the bottom of the reaction tube would have sped up the reaction because stirring would have broken up the globules into smaller pieces. This would have made it easier for the anhydride to react in the presence of water. 3. Give a balanced equation for the hydrolysis of cis-norbornene-5,6-endo-dicarboxylic anhydride. C9H8O3 + H2O C9H10O4 4. Give a detailed mechanism (show electron flow) for the hydrolysis of cis-norbornene- 5,6-endo-dicarboxylic anhydride. III. Experimental Section Procedure The procedure was taken from Williamson et al., pages 627-628: Hydrolysis of cisNorbornene-5,6-endo-dicarboxylic anhydride to the dicarboxylic acid with the following modifications: the anhydride starting material was provided in class rather than using what was made in experiments 48.1 and 48.2, the crystals were not rinsed with water, the crystals were collected using vacuum filtration, and the melting point of the dicarboxylic acid was not taken. Reaction and Theoretical Yield Calculation: Experiment 48.1 Mol MW G mL D IV. C9H8O3. + 0.00119 mol [LR] 164.16g/mol 0.196g 0.14mL 1.417 g/mL H2O 0.139 mol 18.02g/mol 2.5g 2.5mL 1g/mL C9H10O4 0.00119 mol [TY] 182.17g/mL 0.21667g 0.1463mL 1.481 g/mL Results and Discussion Data Observations  It was necessary to bang away with the boiling stick in the reaction tube because the reaction mixture was so gooey and thick.  When the dicarboxylic acid product went into solution it was a clear, colorless liquid.  The final product resulted in white crystals. Starting Amount Mass of Product Percent Yield 0.196g 0.199g (0.199g/0.21667g) x 100 = 92% Analysis The objective of experiment 48.3 was to heat the cis-Norbornene-5,6-endodicarboxylic anhydride, the product obtained in experiment 48.2, in water to hydrolyze the anhydride to its corresponding dicarboxylic acid. A reaction tube was filled with the anhydride, water, and then a boiling stick was added; the tube was then heated over a hot sand bath. The reaction tube was then cooled in ice, and the crystals were collected using vacuum filtration. The crystals had a white, fine appearance, the amount collected was 0.199g, and the percent yield was approximately 92 percent. Although the percent yield was quite high, some possible reasons that could account for the missing crystals were that the reaction tube was cooled in the ice bath after it was heated. The use of the ice bath rushed the crystal formation and some of the crystals may not have fully formed, leading to a percent recovery slightly below 100 percent. V. Works Cited Williamson, Kenneth L.; Minard, Robert D.; Masters, Katherine M. Macroscale and Microscale Organic Experiments, 7th ed., chapter 48; Cengage Learning, Boston, MA 2017