Identification of Alcohols and PhenolsAlcoholsNaming AlcoholsClassifying AlcoholsPractice: Naming and ClassifyingAlcohol Groups are PolarAlcohols Can Hydrogen BondEffects of Hydrogen BondingPhenols are Special AlcoholsChemical Behavior of AlcoholsLucas TestSlide 12Chromic Acid TestOxidation of Primary AlcoholsSecondary AlcoholsPhenolsWhy Aren’t Tertiary Alcohols Oxidized?Visualizing the Chromic Acid TestIodoform TestSlide 20Slide 21Acidity of PhenolIron(III)chloride TestSteam Bath UseProcedural Notes and Safety RemindersIdentification of Alcohols and PhenolsFebruary 14, 2013AlcoholsHydroxyl group (-OH) bonded to CNaming Alcohols1. Find the longest C chain that includes C–OH2. Number it so that C–OH has lowest number possible3. Change the ending of the parent alkane from –e to –ol4. For 3 or more C, include # of C–OH 5. Precede with name and number of other substituents, listed alphabeticallyClassifying AlcoholsPrimary, secondary, tertiary–Depends on the number of C-containing groups attached to the C bearing the -OH groupOHOHHOPractice:Naming and ClassifyingOHOHOHOHAlcohol Groups are Polar-OH groups are polar–Do not share electrons equally–Electrons closer to O; partially negative–Electrons farther from H; partially positiveOH HOC HWaterAlcoholAlcohols Can Hydrogen BondAlcohols can make 3 H-bonds per molecule• 2 bonds through O• 1 bond through HEffects of Hydrogen BondingIncreases boiling point–Must break H bond network to change phaseIncreases water solubility–Can H bond with waterPhenols are Special AlcoholsAll are weak acidspKa values near 10At pH 7, are protonated (phenol)Note: No other alcohols act as weak acids+ H2O + H3O+pKa= 9.95OH O-PhenolPhenoxideChemical Behavior of Alcohols1. Lucas Test2. Chromic Acid Test*3. Iodoform Test4. Acidity of Phenol5. Iron(III)chloride TestReagent: ZnCl2 in concentrated HClResults:–Tertiary OHs: Fast formation of insoluble white layer Lucas TestResults:–Secondary OHs: Slow formation of same white layer with heat–Phenol and Primary OHs: No reactionLucas TestWill NOT perform thistest for safety reasons.Jones Reagent: H2CrO4 in concentrated H2SO4Result:–Primary OHs: Oxidized to carboxylic acid–Secondary OHs: Oxidized to ketone–Tertiary OHs: No reaction–Phenols: Oxidized to benzoquinone (brown tar)Chromic Acid TestOxidation of Primary AlcoholsResult: OH to aldehyde to COOH–Why is this oxidation? Oxidation is the gain of bonds to oxygen and/or the loss of bonds to hydrogen–What gets reduced? ChromiumCr6+ (yellow-orange) Cr3+ (blue)RCH2OHH2CrO4H2SO4RCHOH2CrO4H2SO4RCOOHSecondary AlcoholsResult: OH to ketoneNo further oxidationRCHR'H2CrO4H2SO4RCR'OHOPhenolsConverts phenol into quinoneOH+ H2CrO4OOWhy Aren’t Tertiary Alcohols Oxidized?OHCH3H2CrO4H2SO4No ReactionNo C-H bond attached to the C bearing the -OH group to trade for a new C-O bondVisualizing the Chromic Acid TestQuickTime™ and a decompressorare needed to see this picture.QuickTime™ and a decompressorare needed to see this picture.QuickTime™ and a decompressorare needed to see this picture.QuickTime™ and a decompressorare needed to see this picture.Reagent: I2 in NaOHResults:–Primary and Tertiary OHs: No reaction–Phenols: Forms yellow ppt (not HCl3) Iodoform TestResults:–Secondary OHs: Some form HCI3Those with methyl group attached to the carbon bearing the hydroxyl groupIodoform TestQuickTime™ and a decompressorare needed to see this picture.QuickTime™ and a decompressorare needed to see this picture.Iodoform TestNote: Acetone will produce a positive test result. Make sure to rinse all test tubes thoroughly with water after cleaning them with acetoneSome ketones test positiveReagent: NaOHResult:–Primary, Secondary, and Tertiary alcohols: No reaction –Phenols: Form phenoxide and dissolve Acidity of Phenol+ OH-+ H2OOHO-Reagent: FeCl3Results:–Phenols: Purple-colored complex–All other OHs: No reaction Iron(III)chloride TestSteam Bath UseLucas and Iodoform tests require heatingCannot use Bunsen burners in organic chemistry lab. Why?Covered with concentric rings. Can control “size” of bath by adding or removing rings.Heat water-filled beakerProcedural Notes and Safety RemindersConsider starting with chemical tests instead of physical properties to reduce crowding at hoodChromic acid: Corrosive and carcinogen—so not performed. You must still know results and reactionsPhenol: Toxic and corrosiveReagents for Lucas Test, Iodoform Test, Acidity Test: Contain strong acids or