Question

What is the theoretical yield of polyester from the below reaction:

2. Room temperature method using phenolphthalein Dissolve phenolphthalein (0.005 mole, 1.59 g), solid sodium hydroxide (0.4 g) and tetraethylammonium chloride (TEA) (0.5 g) in 50 mL of deionised water in a 200 ml beaker, then add a magnetic stirrer bar. Add 35mL of dichloromethane to the beaker. Cover the top of the beaker with aluminium foil. Set up a magnetic stirrer to provide continuous stirring at an intermediate speed. This will disperse the organic phase into the water and provide a large interface on which the reaction can take place. This is better than a static situation where the interface is small and the reaction will be consequently slow. Once the organic phase is dispersed introduce while maintaining stirring a solution of terephthaloyl chloride (0.005 mole, 1.01 g) in 15 mL dichloromethane. Continue stirring for a minimum of 10 minutes. The initial deep pink colour of alkaline phenolphthalein will fade rapidly as the reaction proceeds. Record the time it takes for the reaction to appear to reach completion (this time will be used in part 3). After stirring is completed, pour this mixture drop wise into 125 mL of hexane which is being stirred at a medium rate in order to precipitate the polymer. Decant off the solvent and filter under vacuum. Wash the polymer repeatedly with deionised water by stirring vigorously and then filtering. (Note: If a sintered filter was used please rinse with HOT chloroform IMMEDIATELY after removing polymer.) Dry the washed granular polymer in a shallow dish in a vacuum oven at 60-80°C.

Answer 1

Reaction 1 Terephthaloyl chloride phomorphthalein Phonolphthalein I Phenoph thalein + Terephthalop! A polymer product chloride Molecular Formula C20H1404 C₂ H₂O₂ch C28H12O6 318.32 203.02 449 Molecular weight so during this reaction when 318.32 gm of Phenolph- thalein react with 203.02 gm of terephthaloy! chloride gives 449 gm of product

Date Page Reactant of Reactant. 2 203.02 1:0) product 449 318.32 1.59 - .. 318.32 1.59 4 49 (cross multiplication 449 x 1.59 318.32 - 2.242 gm. polyester = 2.242 gm. Theoretical yield of