- #1
seang
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Hi,
I am an electrical engineer, but I have to complete the following procedure:
Synthesis of Esters. (a)
Methyl Ester. The methyl ester of 10-
undecylenic acid was prepared similarly to the method used by Sieval.
The 10-undecylenic acid was dissolved in methanol and allowed to
reflux for 3 h with a small amount of sulfuric acid. Excess methanol
was removed by vacuum. The crude product was dissolved in ether,
washed with a saturated sodium bicarbonate solution, water, then a
saturated NaCl solution, and dried over magnesium sulfate. The identity
of the vacuum distilled product was confirmed using proton NMR.
1H NMR: ä 5.73-5.89 (m, 1H), 4.89-5.04 (m, 2H), 3.67 (s, 3H),
2.25-2.35 (t, 2H), 1.99-2.09 (m, 2H), 1.54-1.69 (m, 2H), 1.23-
1.44 (m, 10H).
(b) 2,2,2-Trifluoroethyl Ester. The fluorinated ethyl ester of 10-
undecylenic acid was prepared similarly to the methyl ester. To 30 g
of 10-undecylenic acid was added 22 g of 2,2,2-trifluoroethanol
dissolved in 40 mL of toluene. This mixture was allowed to reflux
with a small amount of sulfuric acid for 3 h using a Dean-Stark
apparatus. Workup similar to the methyl ester produced a crude product
that was further purified by vacuum distillation. Proton, COSY, and
fluorine NMR confirmed the identity of the product.
1H NMR: ä 5.70-5.90 (m, 1H), 4.86-5.06 (m, 2H), 4.38-4.51
(q, 2H), 2.35-2.45 (t, 2H), 1.98-2.10 (m, 2H), 1.55-1.75 (m, 2H),
1.20-1.50 (m, 10H). Fluorine NMR: single triplet.That word there, WORKUP, is kinda ambiguous to me as an EE. Not sure what part of procedure a.) they are referring to. My best guess is "...washed with a saturated sodium bicarbonate solution, water, then a saturated NaCl solution, and dried over magnesium sulfate."
Any ideas?
I am an electrical engineer, but I have to complete the following procedure:
Synthesis of Esters. (a)
Methyl Ester. The methyl ester of 10-
undecylenic acid was prepared similarly to the method used by Sieval.
The 10-undecylenic acid was dissolved in methanol and allowed to
reflux for 3 h with a small amount of sulfuric acid. Excess methanol
was removed by vacuum. The crude product was dissolved in ether,
washed with a saturated sodium bicarbonate solution, water, then a
saturated NaCl solution, and dried over magnesium sulfate. The identity
of the vacuum distilled product was confirmed using proton NMR.
1H NMR: ä 5.73-5.89 (m, 1H), 4.89-5.04 (m, 2H), 3.67 (s, 3H),
2.25-2.35 (t, 2H), 1.99-2.09 (m, 2H), 1.54-1.69 (m, 2H), 1.23-
1.44 (m, 10H).
(b) 2,2,2-Trifluoroethyl Ester. The fluorinated ethyl ester of 10-
undecylenic acid was prepared similarly to the methyl ester. To 30 g
of 10-undecylenic acid was added 22 g of 2,2,2-trifluoroethanol
dissolved in 40 mL of toluene. This mixture was allowed to reflux
with a small amount of sulfuric acid for 3 h using a Dean-Stark
apparatus. Workup similar to the methyl ester produced a crude product
that was further purified by vacuum distillation. Proton, COSY, and
fluorine NMR confirmed the identity of the product.
1H NMR: ä 5.70-5.90 (m, 1H), 4.86-5.06 (m, 2H), 4.38-4.51
(q, 2H), 2.35-2.45 (t, 2H), 1.98-2.10 (m, 2H), 1.55-1.75 (m, 2H),
1.20-1.50 (m, 10H). Fluorine NMR: single triplet.That word there, WORKUP, is kinda ambiguous to me as an EE. Not sure what part of procedure a.) they are referring to. My best guess is "...washed with a saturated sodium bicarbonate solution, water, then a saturated NaCl solution, and dried over magnesium sulfate."
Any ideas?