Today: Hand in MiniQuiz Nitro compounds and inert compounds IR; UV Next time, 11/18 (no class on 11/11): Mass spectrometry Bring your Unknown 3 spectra if you have them

Nitro Compounds Typical properties? Classification test: Practice 5) Always do with a known compound to compare! Derivatives: Reduce to amine and then prepare amine derivatives Preliminary tests? Solubility Classification tests Derivatives Spectra

“Inert Compounds” Alkanes Aromatic Hydrocarbons Alkyl halides

What information do we get from an IR spectrum? What is the cause for the typical absorptions? Spectroscopy Infrared Spectroscopy (IR) IR region = cm -1 (cm -1 unit is the wave number scale and is given by 1/wavelength in cm) E= h

butyl acetate Fingerprint region

Aromatics aromatic overtones

Alcohols Gas phase!

Phenol

Ketones

Carboxylic Acids

See Chapter in your Lecture text (conjugated systems)  to  * HOMO to LUMO A =  x C x l A = absorbance;  = molar absorptivity C = concentration in mol/L; l = sample pathlength in cm UV/Visible Spectrophotometry Which compounds generally absorb in the UV? Which compounds absorb in the visible range? CH 4 ? CH 3 (CH 2 ) 10 CH 3 ? Ethanol? Benzene? Naphtalene?  -Carotene? FeCl 3 ?

UV/Visible Spectrophotometry

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Next time: Mass Spectrometry Bring you Unknown 3 Spectra to class!