1) In a 100 mL flask is combined 27 mL of acetic acid (d = 1.049), 21 mL of 1-propanol (d = 0.900) and a catalytic amount of p-toluenesulfonic acid.

a) Write a balanced chemical equation for this ester synthesis. using line bond structure. Write the names, molecular formula, and molecular weight beneath each structure. Circle and name the functional group in each molecule.

b) What is the theoretical yield of this reaction? (Show calculations)

c) What is the percent yield if 7.1 grams of ester is isolated? (Show calculations)

2) the catalyst p-toluenesulfonic acid was used as a catalyst in the ester synthesis. Indicate true or false for each statment.

a) the acid catalyst shift the position of the final equilibrium

b) the acid catalyst increase the rate of the reaction

c) the acid catalyst allows for yields over 100%

d) the acid catalyst decreases the rate of the reaction

3) What is the purpose for the extractions with aqueous sodium bicarbonate sulotion after the synthesis. Discuss changes in solubility as result of reaction with sodium bicarbonate and provide a balanced chemical equation.

4) For each of the folowing esters draw the structures of the carboxylic acids and alcohol from which they can be synthesized.

a) Isopentyl (amyl) acetate.

b) Octyl acetate

c) n-Propyl acetate

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Show transcribed image text Exercise 1: Esterification Note aroma before and after boiling Structure and IUPAC name of product fo Reaction Mixture A. 10 drops CHsCOOH+10 drops octanol + 2 drops concentrated H2S04 (catalyst) 8. 10 drops CH,COOH+ 10 dropspentanolo he ale + 2 drops concentrated H2504 (catalyst) C. 1 pinch salicylic acid + 10 drops methanol + 2 drops concentrated H SO4 (catalyst) test tube. Put the first tube in a beaker of boiling water for 5 min. Pour * Prepare mixture in a contents of the tube into a beaker with 50mL distilled H,O. Waft vapor towards you to observe smel 1. Write a balanced chemical equation for each reaction showing expanded chemical formulas. C. 2. If you mixed 10 drops of ethanol and 10 drops of CHaCOOH, calculate the theoretical mass in grams of the ester formed in the reaction. Show all calculation steps. Assume the following 20 drops-1 mL Density of ethanol:0.90 g/mL [CH3COOH-17.4 M
Exercise 2: Saponification (Refer to a separate handout for instructions) Questions 2. What is the purpose of adding saturated NaCi to the reaction mixture? nnl 2. Describe the pH, appearance and sudsing ability of the soap after 24 hours. 3. Write the chemical equation for the saponification reaction, showing the structures of the reactants and products. Exercise 3: Oxidation-Reduction (Redox) Reaction mixture Observations 5 drops H:0+5 drops Tollen's reagent 5 drops glucose+ 5 drops Tollen's reagent Prepare mixture in a clear glass ornament, cover tightly with parafilm, and swirl continuously for 2 m ""Use the same ornament for the second mixture; cover with parafilm and swirl vigorously for 2 minutes. 5 drops H20+ 5 drops Benedict's reagentu 5 drops fructose + 5 drops Benedict's reagenthin enongi 5 drops glucose + 5 drops Benedict's eagentellor theongrd et lode ho **Prepare each mixture in a labeled test tube and put the tubes in a beaker of boiling water for 5 minutes. Note color change and time of reaction. Discard contents into the designated waste container. C4 Questionss t 1. What is the visible observation for a positive Tollen's test? a positive Benedict's test? 2. Write the chemical equation for the positive reaction, showing the structures of the reactants and products.

Procedure:

In a 5-mL round bottom flask, add 120 mg of 4-aminobenzoic acid (often called PABA for p- aminobenzoic acid), 1.5 mL of absolute ethanol (absolute ethanol is completely free of water and can be found on the hooded shevles), and 3 boiling chips. Heat this mixture on a sand bath until all the solid dissolves. Cool in ice and then add 0.25 mL of concentrated sulfuric acid dropwise. (One drop at a time.) A large amount of precipitate will form when the sulfuric acid is added, but this will dissolve during the reflux that follows. Attach an air condenser from the microscale kit, and reflux gently for 60- 75 min. Check periodically to be sure that the mixture is refluxing gently, and that the ring of condensation of solvent lies somewhere along the inner surface of the air condenser; loss of solvent will cause overheating and a significant decrease in yield. Detach the air condenser from the reaction tube and allow the reaction mixture to cool to room temperature. Using a Pasteur pipet, transfer the reaction solution to a 10-mL Erlenmeyer flask and add 3 mL of distilled water. Dropwise, add saturated sodium bicarbonate (about 3 mL, approximately 10% or 1 M) to neutralize the excess sulfuric acid and the ammonium sulfate salt form of the amino ester (making it neutral and insoluble in water). After each addition of the sodium bicarbonate, agitate the solution to mix thoroughly. Extensive CO2 evolution (gas) and frothing will be observed until the mixture is nearly neutralized. As the pH increases, a white precipitate of benzocaine is produced. When gas no longer evolves as you add a drop of sodium bicarbonate, check the pH of the solution with "Alkacid" pH paper and, if it is less than 8, add further portions of saturated sodium bicarbonate solution. Collect the benzocaine by vacuum filtration using a Hirsch funnel. Use three 1-mL portions of cold water to wash the product crystals from the flask onto the funnel. Make sure the product is rinsed thoroughly with cold water water. After the product has dried thoroughly by leaving it in an open container until the next lab period, weigh it, calculate the % yield, and determine its melting point. The m.p. of pure benzocaine is 92Â°C.

Benzocaine Data Sheet

1) Draw the reaction scheme

2) Find the limiting reactant, and calculate the theoretical yield: 2.41g

3) Provide the mass of recovered product, and calculate the percent yield: 200 F

4) Provide the melting point and melting point range of your product. Compare it to the literature value

5) Below is the structure of benzocaine. Correlate each proton to the corresponding peak in the 1H NMR spectrum