Question

based on the following H NMR and C NMR determine which acid is present:

2,5- dichlorobenzoic acid

2,4,6- trimethylbenzoic acid

3-chlorobenzoic acid

3-hydroxybenzoic acid

2-iodobenzoic acid

7.3464 7.3243 7.3184 7.2563 See all 180 177.3251 "Bean, Klimabeth EM ACID"21" 166.5565 160 C'NMR Acid 140 140.0977 135.1928 datalos Bep_Spee Fall 2017 Section Aids - 123.5895 121.8342 120 117.5069 100 110-110 = Benene Ring 80 (ppm] CDCI 82.3304 81.9045 81,4789 50 fred

$HNMR - Acid Bean irabeth NEW ACID 5:\n\data\chnos\sep spec Mall 2019 section helda 6.8593 6.8414 6.8025 6.7786 6.7520 15 1$

Answer 1

From 13C spectra, all the 6-aramatic carbons appears at seperate chemical shift indicate unsymmetrical struture. V OH only three trotons in aromatic region, hence neglected 2.5- dichlorobenzoic acid Symmetric structure, and should give a single peak for 2H in aromatic region, hence neglected. 2.4,6-trimethylbenzoic acid 3-chlorobenzoic acid Although unsymmetric structures, and 4H present, but only 3 protons will have ortho-coupling from 1 proton NMR, it is clearly seen that all the four protons showing the ortho coupling in addition to meta coupling. HOLA 3-hydroxybenzoic acid OH Unsymmetric structure, four protons in aromatic region. From 11 proton NMR, it is clearly seen that all the four protons showing the ortho coupling in addition to meta coupling. 2-iodobenzoic acid 28HZ 2-3 Hz -8 H 2-3 Hz

H'NMR - Acid н. на о кон residual solvent peak from CDCI, 5 Hydrogen Types

All the chemical shifts are assigned based on the coupling pattern and roofing effect as observed.