Chapter 11: Reactions of Alcohols – Vocabulary Review

A comprehensive set of vocabulary flashcards summarizing the major reagents, mechanisms, and concepts presented in the Chapter 11 lecture on reactions of alcohols.

Dehydration (of alcohols)

Acid-catalyzed removal of water from an alcohol to give an alkene; favored for 2°/3° alcohols at higher temperatures (≈180 °C with H₂SO₄).

Bimolecular condensation (ether formation)

Acid-mediated SN2 reaction where two 1° alcohol molecules form a symmetrical ether (e.g., diethyl ether) at ≈140 °C.

Esterification (Fischer)

Reversible acid-catalyzed reaction between a carboxylic acid and an alcohol to produce an ester and water.

Oxidation (of alcohols)

Process that increases the number of C–O bonds at the carbinol carbon, converting 1° alcohols → aldehydes → acids and 2° alcohols → ketones.

Tosylation

Conversion of an alcohol into a p-toluenesulfonate ester (ROTs) using TsCl/pyridine, creating an excellent leaving group.

Substitution of alcohols

Replacement of the –OH group by a halide (R–X) via SN1 or SN2 mechanisms using HX, PX₃, SOCl₂, etc.

Reduction to alkanes (alcohols)

Two-step sequence: convert –OH to a tosylate (or dehydrate to an alkene) then reduce with LiAlH₄ or H₂/Pd to give an alkane.

Primary alcohol (1°)

Alcohol in which the carbinol carbon is attached to one other carbon; oxidizes first to an aldehyde, then to a carboxylic acid.

Secondary alcohol (2°)

Alcohol whose carbinol carbon is attached to two carbons; oxidizes to a ketone.

Tertiary alcohol (3°)

Alcohol with the carbinol carbon attached to three carbons; generally resistant to oxidation without C–C bond cleavage.

Chromic acid (H₂CrO₄)

Strong chromium(VI) oxidant generated from CrO₃ or Na₂Cr₂O₇/H₂SO₄; converts 1° alcohols to acids and 2° alcohols to ketones.

Pyridinium chlorochromate (PCC)

Mild Cr(VI) oxidant (CrO₃·pyridine·HCl) that stops at the aldehyde stage when oxidizing 1° alcohols.

Sodium hypochlorite (NaOCl)

Household bleach; in HOAc and with TEMPO it acts as a mild, chromium-free oxidant for alcohols.

TEMPO

Stable nitroxyl radical (2,2,6,6-tetramethylpiperidinyl-1-oxy) used catalytically with NaOCl to selectively oxidize 1° alcohols to aldehydes or acids.

Chromate ester

Intermediate formed when an alcohol oxygen bonds to Cr(VI); its E2-type elimination gives the oxidized carbonyl compound.

Swern oxidation

Oxidation of 1°/2° alcohols using DMSO, (COCl)₂, and Et₃N at −60 °C, yielding aldehydes or ketones without heavy metals.

Dess–Martin periodinane (DMP)

Hypervalent iodine reagent that cleanly oxidizes 1° alcohols to aldehydes and 2° alcohols to ketones under mild conditions.

Sodium borohydride (NaBH₄)

Selective hydride donor that reduces aldehydes and ketones (not most esters or acids) to primary and secondary alcohols.

Lithium aluminum hydride (LiAlH₄)

Powerful hydride reducing agent that converts carbonyl compounds, epoxides, tosylates, etc., to alcohols or alkanes.

Tosyl chloride (TsCl)

Reagent used with pyridine to form tosylate esters from alcohols; introduces the –OTs leaving group.

Tosylate ester (ROTs)

Alcohol derivative where –OH is replaced by p-toluenesulfonate; excellent leaving group in SN2/E2 reactions.

Chromic acid test

Qualitative assay: 1°/2° alcohols oxidize Cr(VI) (orange) to Cr(III) (green/blue), while 3° alcohols give no color change.

Williamson ether synthesis

SN2 reaction of an alkoxide ion with a 1° alkyl halide or tosylate to form an ether.

Alkoxide ion

Conjugate base of an alcohol (RO⁻); a strong nucleophile and base generated by Na, K, or NaH.

Carbocation

Positively charged carbon intermediate; formed during E1 dehydration and SN1 substitution of 2°/3° alcohols with HX.

Fischer esterification

Acid-catalyzed equilibrium reaction between an alcohol and carboxylic acid producing an ester.

Diethyl ether (industrial route)

Formed by acid-catalyzed condensation of two ethanol molecules at 140 °C; classic example of bimolecular dehydration.

Pinacol rearrangement

Acid-induced migration in vicinal diols (e.g., pinacol) producing a carbonyl compound (pinacolone).

Periodic acid cleavage (HIO₄)

Oxidative cleavage of 1,2-diols to carbonyl fragments via a cyclic periodate intermediate.

Pinacolone

3,3-Dimethyl-2-butanone; product of acid-catalyzed rearrangement of pinacol.

Glyceryl trinitrate (nitroglycerin)

Explosive tri-ester formed from glycerol and nitric acid; example of an inorganic nitrate ester.

Phosphate ester

Product of phosphoric acid reacting with an alcohol; key linkage in DNA backbones.

Phosphorus tribromide (PBr₃)

Reagent that converts 1°/2° alcohols to alkyl bromides via an SN2 mechanism with inversion of configuration.

Thionyl chloride (SOCl₂)

Reagent that converts alcohols to alkyl chlorides, releasing SO₂ and HCl; often retains stereochemistry via SOCl₂/pyridine variant.

Phosphorus triiodide (PI₃)

Generated in situ from P and I₂; converts 1°/2° alcohols to alkyl iodides.

HX conversion (SN1)

Use of strong haloacids (HBr, HCl) to replace –OH with halide via a carbocation; fastest with 3° alcohols.

Lucas reagent

Mixture of HCl and ZnCl₂; promotes substitution of 2°/3° alcohols to chlorides, useful for classifying alcohols.

Methanol poisoning

Metabolic oxidation of methanol to formaldehyde and formic acid, leading to toxicity; treated with excess ethanol.

Ethylene glycol poisoning

Metabolism of antifreeze to oxalic acid; competitive treatment with ethanol blocks the toxic pathway.

E1 dehydration

Acid-catalyzed elimination where an alcohol forms a carbocation that loses a proton to give an alkene plus water.

Tosic acid (p-TsOH)

Strong organic sulfonic acid; conjugate acid of the tosylate ion and useful acid catalyst.

Tosylate leaving group

Resonance-stabilized p-toluenesulfonate anion (TsO⁻); an excellent leaving group in nucleophilic substitutions.

Alkyl hypochlorite

Intermediate formed when an alcohol reacts with HOCl; its elimination of HCl oxidizes the carbon.

Carbinol carbon

Carbon atom bearing the –OH group in an alcohol; site of oxidation state changes.

Oxidation state of carbon

Measure of electron ownership; rises as C forms more bonds to electronegative atoms (O) and fewer to H or C.

Hypochlorous acid (HOCl)

Protonated form of NaOCl in HOAc; active oxidizing species with alcohols.

Sodium dichromate (Na₂Cr₂O₇)

Source of Cr(VI); with H₂SO₄ forms chromic acid for strong oxidations.

Periodate (IO₄⁻)

Anion in HIO₄ that cleaves vicinal diols to carbonyl compounds.

Osmium tetroxide (OsO₄)

Reagent that converts alkenes to cis-diols, which can then be cleaved by HIO₄.