Question

Synthesis Module L Synthesis of Benzopinacolone In this reaction benzophenone goes through a proto of isopropyl alcohol. enone goes through a photochemical dimerization reduction to form benzopinacolone in the presence он он Ph + Acetone hv C- Phi Ph Ph-C- Ph-CSP + (CHỊ) CHOH. Ph Benzophenone Benzopinacol CH,COH, I Phác CầPh Ph Benzopinacolone Preparation of benzopinacol Add 2.0 gm benzophenone and 10 mL 2-propanol in a 8-inch test tube and heat over a steam bath until a homogeneous solution is obtained. Label your test tube with your name and section number, add two drops of glacial acetic acid, place a cork on the test tube, and submit it to your TA for irradiation in a photochemical reactor. After the irradiation is completed and the mixture is cooled to room temperature, filter the crystals (benzopinacol) suspended in the solution, dry them thoroughly, and take the melting point of it. B. Preparation of Benzopinacolone, Pinacol Rearrangement In a 50-ml round bottom flask, add 1.0 gm of benzopinacol. 6 mL acetic acid, and one small crystal of iodine and reflux for 15 minutes using a heating mantle or thermowell. Cool the reaction vessel to room temperature, add 6 mL of ethanol, and chill the flask in an ice bath for 5 minutes. Collect the benzopinacolone crystals by suction filtration and rinse the crystals with small amount of cold ethanol and determine its percent yield and melting point. Make a KBr pellet of each of hezoninacal and benzopinacolone and obtain an IR spectrum of them. Compare the IR spectrum of bezopinacol with that of benzopinacolone. You should carefully assign the IR-peaks to the appropriate stretching/bending vibrations

Amount of Benzopincol recovered = 1.1g

Amount of Benzopinacolone recovered = 0.5g

Theoretical/Percent yield of Benzopinacol?

Theoretical/Percent yield of benzopinacolone?

Answer 1

OH OH the + (CH] CHOH hody Ph-e - e-Ph teh och Ph Ph 182 g t Benzopinacol 366 g, (Benzophenone) will to & CHEH , I Ph o i Ph-Ć --PA (Benzopinacalone) Ph 3489 from 182 g of benzophenone amount of beuropinacal formed is 366 g a от 99 of eduzople hoh аlmоunt оf blue oping formed will be 1366 x 19 (792 x2) 9 it = 4,0219 g of benzo- pinacol Theoretical yield of benzopinacel is 4.6219 g Actual yield of beazopinacal is lyg percent yield of benzopinacol is - = Actual yield Theoretiene xloo = 6.6219X10) = 27.35 Pied Yield 27.35%

Percent yield of Benzopina col is 27.35% - от 566 9 of buzo Pinacs, 248 10 pic benzo acolone is formed. so, from. 1 g of benzopinacol, 1348 x1) = 0.9508 1366 g of benzopinacolone is formed. So, Theoretical yield of benzopina colone is 0.9508 Actual yield of benzopinacolone is o.sg % yield = Actual yield Theoretical yield lov benzopina colone 0.5 x 100 0.9508 = 52.587 7. percent yield of benzopina colone is 52.587%