A catalyst is a key material used in efficient chemical conversions. Today, about 90 % of chemical p — Organic Chemistry Chemistry Question

A catalyst is a key material used in efficient chemical conversions. Today, about 90 % of chemical processes use catalysts. Large-scale catalytic processes are employed, for example, in oil refining and petrochemical processes. In the petroleum industry, soluble liquid acids, such as sulphuric acid, are often used as catalysts in homogeneous systems. Since liquid acids are difficult to recover, however, insoluble solid acids are welcome for use in environmentally benign processes.

Various solid materials are capable of releasing H⁺ ions into liquids, and such materials can be utilized as solid acid catalysts. H⁺-type cation-exchange resins are typical examples of solid acids. In this experiment, you will examine the catalysis of an H⁺-type cation-exchange resin for hydrolysis of ethyl acetate.

R₁COOR₂ + H₂O --(H⁺)^--> R₁COOH + R₂OH

Chemicals and reagents
* toluene, C₆H₅CH₃
* Amberlyst®-15 (H⁺ form, dry)
* ethyl acetate, liquid, (reactant)
* phenolphthalein (0.5 wt.% solution in ethanol/water (1/1))
* sodium hydroxide (NaOH) standard solution, 0.02 mol dm–3 (concentration accurately determined)

Apparatuses and glassware
* burette (25 cm₃)
* Erlenmeyer flasks (100 cm₃ × 6)
* glass vials (10 cm₃ × 6; must be dried)
* graduated pipette (5 cm₃)
* magnetic stirrer
* stirring bar
* Pasteur pipette (dropper)
* reflux condenser
* silicone plug
* thermometer
* three-necked flask (250 cm₃)
* volumetric pipettes (1 cm₃ and 3 cm₃)
* water bath

Procedure
(1) Assemble the experimental setup as shown in Fig. 36.1. [VISUAL] The chemicals will be charged through the unequipped neck.
(2) Charge water (100 cm₃) and Amberlyst^-15 (1.0 g) into the three-necked flask. Then heat and stir the solution.
(3) When the solution reaches a constant temperature of 60 °C, add ethyl acetate (5 cm₃) to the flask. This will be the start time of the reaction.
(4) Charge six Erlenmeyer flasks with cold water (50 cm₃) and add a few drops of phenolphthalein to each flask. Keep the flasks at room temperature.
(5) Fill a 25 cm₃ burette with the NaOH solution (0.3 mol dm–3).
(6) Ten minutes after the start of the reaction, stop stirring the mixture in order to settle out the catalyst, and transfer about 5 cm₃ of the solution to a glass vial using a graduated pipette. Immediately, transfer 3 cm₃ of the solution to an Erlenmeyer flask charged with water with a volumetric pipette. (You can directly transfer the solution from the reactor to the Erlenmeyer flask, depending on your skill level). Stir the solution again.
(7) Repeat procedure (6) at intervals of 10 min until 60 min have elapsed from the start of the reaction. Then similarly prepare five more samples for titration in Erlenmeyer flasks.
(8) Titrate six samples in the Erlenmeyer flasks with the NaOH solution. It is recommended that you calculate the amount of the NaOH solution required for complete hydrolysis of ethyl acetate prior to the titration.