1) Refer to the posted IR spectra of pure dibenzalacetone andidentify the C=O and C=C stretching bands of dibenzalacetone (givethe frequencies)

2) An IR spectrum of a student dibenzalacetone product will beposted, compare it to the pure dibenzalacetone, acetone andbenzaldehyde spectra and comment on

(i) whether it shows product

(ii) whether it is pure product or contaminated withreactants.

3) Why does the dibenzalacetone C=O stretching vibration occurat a lower frequency than the 1720 cm^-1 ketone C=O peakin acetone?

2.5 2.6 2.7 2.8 2.9 3 100 90 80 70 60 50 40 30 20 10 0 4000 % A N S T C 3800 3600 3400 Pure DBA 3.5 4.5 3200 3000 2800 2600 2400 2200 5 2000 5.5 1800 MICRONS 6 1600 WAVENUMBERS 7 1400 8 9 10 1200 1000 11 12 800 13 14 15 NICOLET 20SX FT-IR 16 17 18 19 21 22 +0.0 600 ABSORBANUE C .05 0.1 0.2 0.3 -0.4 0.5 -0.6 0.7 0.8 0.9 1.0 2.0 450