Análise Espectral de Compostos

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c) Benzaldehyde has two bands for the aldehyde H at 2830-2700 cm⁻¹ that are not present in the spectrum of the ketone, acetophenone. d) The primary amine has two bands in the 3400-3250 cm⁻¹ region whereas the secondary amine has only one. 13.12 a) The strong absorption at 1715 cm⁻¹ is typical for a carbonyl group of a ketone. The absorption in the region of 3000-2850 cm⁻¹ is indicative of H's bonded to sp³-hybridized C's. There is no evidence for the presence of a C=C bond. b) The strong and broad OH absorption centered at 3000 cm⁻¹ along with the carbonyl absorption at 1716 cm⁻¹ are typical for a carboxylic acid. There is no evidence for the presence of a C=C bond. c) The two bands in the region of 2830-2700 cm⁻¹ and the carbonyl absorption at 1696 cm⁻¹ provide evidence for the presence of an aldehyde. The observed shift of the carbonyl band to a lower wavenumber indicates that it is a conjugated aldehyde. The absorptions in the region of 3100-3000 cm⁻¹ are due to sp²-hybridized C-H bonds, and those in the region of 3000-2850 cm⁻¹ are due to sp³-hybridized C-H bonds. The appearance of four bands in the 1600-1450 cm⁻¹ region and the strong band near 750 cm⁻¹ indicate the probable presence of an aromatic ring. 13.13 a) NH₂, two bands, 3400-3250 cm⁻¹; =CH, 3300 cm⁻¹; -CH, 3000-2850 cm⁻¹; C=C, 2150-2100 cm⁻¹. b) OH, 3000 cm⁻¹, very broad; -CH, 3000-2850 cm⁻¹; -C=N, 2260-2200 cm⁻¹, medium; C=O, 1710 cm⁻¹. c) -CH, 3000-2850 cm⁻¹; C=O, 1740 cm⁻¹; C-O, 1300-1000 cm⁻¹. d) =CH, 3100-3000 cm⁻¹; -CH, 3000-2850 cm⁻¹; C=O, 1695-1675 cm⁻¹; aromatic ring, 1600-1450 cm⁻¹ (four bands), and 900-675 cm⁻¹. 13.14 a) The broad absorption centered at 3300 cm⁻¹ indicates the presence of a hydroxy group. The absorption at 2900 cm⁻¹ suggests the presence of hydrogens on sp³-hybridized C's. The compound is a saturated alcohol. b) The two bands in the 3400-3250 cm⁻¹ region indicate the presence of an NH₂ group. The absorption at 2900 cm⁻¹ shows the presence of hydrogens on sp³-hybridized C's. The compound is a saturated primary amine. c) The absorptions in the region of 3100-3000 cm⁻¹ are due sp²-hybridized C-H bonds, and those at 3000-2850 cm⁻¹ are due to sp³-hybridized C-H bonds. The appearance of four bands in the 1600-1450 cm⁻¹ region and the strong band near 750 cm⁻¹ indicate an aromatic ring. The strong 207