| Demonstration of Microscale Projection Experiments -
Chemistry en miniature Objectives: Ester Hydrolysis, Nucleophilic Acyl Substitution Peter Keusch |
Hazards and safety precautions:
Safety glasses, gloves and good ventilation required. Experimental procedure: 1 mL of water is pipetted into each of the three test tubes. One drop of sodium hydroxide solution and 1 drop of phenolphthalein solution are added to each of the test tubes. Two of the solutions are mixed with ester. The third solution acts as reference solution.
A Pasteur pipette is placed in T1 and in T2. The phases are simultaneously mixed by gentle squeezing of the pipette bulbs. Results The solution in T2 fades immediately to colorless (Photo 1). The red solution in T1 turns bright gradually (Photo 2), until it becomes colorless after a few minutes.
|  < Discussion: · The carboxylic acid formed by the ester hydrolysis is responsible for the decolorization of the red solutions (1).  · The high reactivity of the oxalic acid diethylester is caused by electron-withdrawing effect of the two adjacent carbonyl groups (2), which facilitates the attack of nucleophile.  General experimental instructions and index of experiments 
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