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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
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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
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“Inert Compounds” Alkanes Aromatic Hydrocarbons Alkyl halides
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What information do we get from an IR spectrum? What is the cause for the typical absorptions? Spectroscopy Infrared Spectroscopy (IR) IR region = 4000 - 400 cm -1 (cm -1 unit is the wave number scale and is given by 1/wavelength in cm) E= h http://www.chem.ucla.edu/~webspectra/index.html
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butyl acetate Fingerprint region
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http://www.chem.ucla.edu/~webspectra/index.html
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Aromatics aromatic overtones
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http://www.chem.ucla.edu/~webspectra/index.html
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Alcohols Gas phase!
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Phenol
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Ketones
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Carboxylic Acids
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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 ?
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UV/Visible Spectrophotometry
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max
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Next time: Mass Spectrometry Bring you Unknown 3 Spectra to class!
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