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216 H W10-E1-key

# 216 H W10-E1-key - Name_Key 216 H W10-Exam No 1 Page 2 I(30...

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Name________ Key ____________________ 216 H W10-Exam No. 1 Page 2 I (30 points) Treatment of 8.92 mL of benzene ( 1 ; d = 0.874 g/mL) with 12 g of succinic anhydride ( 2 ) and 16 g of aluminum chloride (AlCl 3 ; Mw 133.3) at 0 °C resulted in, upon acidic work-up, the formation of carboxylic acid 3 . All of the 3 thus produced was immediately treated with 39.1 g of Cs 2 CO 3 (Mw 325.8) and 17.0 g of CH 3 I (Mw 142) to afford 15.4 g of compound 4 (C 11 H 12 O 3 ; Mw 192 g/mol). Note: Mw refers to a molecular or formula weight. AlCl 3 H 3 O + -work-up 0 °C ; O O O + 1 2 3 Cs 2 CO 3 CH 3 I 4 (C 11 H 12 O 3 ) (1) (a) (4 points) What is the limiting reagent in this synthesis of 4 from 1 ? Show your work. 1 : (8.92 mL) x (0.874 g/mL) = 7.80 g 7.80 g/78 g/mol = 0.10 mol; 2 : 12 g / (100 g/mol) = 0.12 mol; AlCl 3 : 16 g / 133.3 g/mol) = 0.12 mol; Cs 2 CO 3 : 39.1 g / (325.8 g/mol) = 0.12 mol (effectively 0.24 mol); CH 3 I: 17.0 g / (142 g/mol) = 0.12 mol. Therefore, 1 is the limiting agent. (b) (4 points) What is the theoretical yield (by weight) of 4 ? Show your work. 0.10 mol of 4 should be formed 0.10 mol x (192 g/mol) = 19.2 g – theoretical yield (c) (2 points) What is the percent yield of 4 in this experiment. Show your work. (15.4 g / 19.2 g ) x 100 = 80% yield. (2) (11 points) Compound 4 (C 11 H 12 O 3 ) has the following spectroscopic properties: IR (liquid film): 3062, 3030, 2990, 2963, 2919, 1738 (strong), 1687 (strong), 1597, 1582 cm -1 [no peaks in the 4,000-3100 cm -1 region]; 1 H NMR (400 MHz, CDCl 3 ) δ 2.75 (2H, t, J = 7.0 Hz), 3.31 (2H, t, J = 7.0 Hz), 3.69 (3H, s), 7.46 (2H, t, J = 8.1 Hz), 7.55 (1H, t, J = 8.1 Hz), 7.93 ppm (2H, d, J = 8.1 Hz); 13 C NMR (22.5 MHz, CDCl 3 ) δ 28.06, 33.43, 51.75, 128.03, 128.62, 133.20, 136.63, 173.30, 198.02 ppm Draw in the box below the structure of compound 4 and assign all aromatic H peaks and 13 C peaks at 51.75, 173.63, and 198.01 ppm by writing their chemical shifts right next to the corresponding nuclei.

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216 H W10-E1-key - Name_Key 216 H W10-Exam No 1 Page 2 I(30...

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