Chapter 15

Organic Chemistry

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diols alcohols in which two hydroxyl groups are present thiols are compounds that contain an –SH group phenols compounds of the type ArOH 15.1 Sources of Alcohols methanol used to be prepared from production of charcoal no prepared by reduction of carbon monoxide with hydrogen used for preparation of fermaldehyde and MTBE (tert-butyl methyl ether) also used as fuel methanol is colorless, bp at 65°C, miscible with water, poisonous vegetables with yeast ferment to produce ethanol and carbon dioxide max alcohol content is 15% but distillation allows higher ones to be produced (alcohol boils before water) synthetic ethanol produced from petroleum by hydration of ethylene isopropyl alcohol prepared from petroleum by hydration of propene, bp of 82°C major component of rubbing alcohol has weak antibacterial properties a reaction that is characteristic of one functional group often serves as a synthetic method for preparing another SEE TABLE 15.1 FOR PREVIOUSLY DISCUSSED ALCOHOL REACTIONS 15.2 Preparation of Alcohols by Reduction of Aldehydes and Ketones using Pt Pd Ni or Ru as catalyst, hydration of aldehyde or ketone gives alcohol aldehyde produces primary alcohol ketone produces secondary alcohol for lab purposes, sodium boronhydride and lithium aluminum hydride are used as reducing agents (both metal hydrides) sodium boronhydride can just be directly added to an aq or alcoholic solution of aldehyde or ketone lithium aluminum hydride reacts violently with water and alcohols, must be used with solvents like anhydrous diethyl ether or THF, also requires a hydrolysis step reaction of sodium boronhydride and lithium aluminum hydride with carbonyl compounds are a lot like Grignard reactions except they function as hydride donors (not carbanion sources) SEE REACTION MECHANISM ON PAGE 627 at no point H2 is involved H added to C from BH4-, H added to O from solvent (water, methanol, ethanol) same idea with lithium aluminum hydride except reduction done in diethyl ether and hydrolysis done after in aq acid (water counts) neither of the reducing agents will reduce isolated C=C double bonds allows you to selectively reduce a carbonyl group 15.3 Preparation of Alcohols by Reduction of Carboxylic Acids and Esters LiAlH4 must be used to reduce carboxylic acids to primary alcohols (strong enough) esters are easier to reduce, but still use LiAlH4 (otherwise move very slowly and require extreme conditions) produces a primary alcohol and another alcohol
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15.4 Preparation of Alcohols from Epoxides Grignard reagents (RMgX) react with ethylene oxide to produce a primary alcohol which
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Chapter 15 - diolsalcohols in which two hydroxyl groups are...

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