Alcohols, Phenols and Ethers — MHT-CET Chemistry

Formulas (2)

• Allylic, Benzylic and Vinylic Alcohols, and 1°/2°/3° · Two labels on the OH carbon
  $$\text{degree: } 1^\circ/2^\circ/3^\circ \text{ by carbons attached};\quad \text{allylic: C=C next door};\ \text{benzylic: ring next door};\ \text{vinylic: OH on C=C}$$
• Molecular Formula and the Preparations of Alcohols · The two hydrations
  $$\text{RCH=CH}_2 \xrightarrow{\text{B}_2\text{H}_6;\ \text{H}_2\text{O}_2/\text{OH}^-} \text{RCH}_2\text{CH}_2\text{OH};\qquad \text{RCH=CH}_2 \xrightarrow{\text{H}_2\text{SO}_4;\ \text{H}_2\text{O}} \text{RCH(OH)CH}_3$$

Reference tables (1)

Watch out for (3)

• Calling but-3-en-1-ol allylic
  → Allylic, Benzylic and Vinylic Alcohols, and 1°/2°/3°
• Reading '-ol' endings as OH counts
  → Monohydric, Dihydric, Trihydric: the Named Diols and Phenols
• Putting the OH on the wrong carbon in hydroboration
  → Molecular Formula and the Preparations of Alcohols

Formulas (3)

• Carbinol Names and the Butyl Alcohols · Carbinol rule
  $$\text{R}_1\text{R}_2\text{R}_3\text{C-OH} \to \text{(R}_1\text{ R}_2\text{ R}_3\text{) carbinol, alphabetical}$$
• IUPAC Names From a Drawing: Ring Alcohols, Ring Ethers, Alkenols · Locant rules
  $$\text{OH carbon} = \text{C1} \to \text{lowest locant SET for substituents} \to \text{alphabetical tie-break}$$
• Isomer Pairs: Alcohol–Ether, Position, Metamers · Same formula, or no isomerism
  $$\text{C}_4\text{H}_{10}\text{O}: \text{ butanols (alcohol)} \leftrightarrow \text{ethoxyethane / methoxypropane (ethers)}$$

Reference tables (1)

Watch out for (4)

• Naming isobutyl alcohol 'isobutyl carbinol'
  → Carbinol Names and the Butyl Alcohols
• Swapping pyrogallol and phloroglucinol
  → The Named Phenols: Common Name ↔ IUPAC Name
• Numbering the ring the short way
  → IUPAC Names From a Drawing: Ring Alcohols, Ring Ethers, Alkenols
• Assuming any two ethers are metamers
  → Isomer Pairs: Alcohol–Ether, Position, Metamers

Formulas (3)

• Boiling Points: H-Bonding, Chain Length, Branching · Boiling-point levers
  $$\text{H-bonding} \uparrow,\ \text{chain length} \uparrow \Rightarrow \text{b.p.} \uparrow;\qquad \text{branching} \uparrow \Rightarrow \text{b.p.} \downarrow$$
• Solubility in Water and the Kinds of Hydrogen Bond · Solubility order
  $$\text{R-OH} > \text{R-NH}_2 > \text{R-H} \quad (\text{H-bonding with water decides})$$
• p-Nitrophenol Melts Highest: Inter- Versus Intramolecular H-Bonds · Which H-bond
  $$\text{ortho: intramolecular} \Rightarrow \text{low m.p., volatile};\qquad \text{para: intermolecular} \Rightarrow \text{high m.p.}$$

Watch out for (3)

• Ranking iso-butyl above sec-butyl
  → Boiling Points: H-Bonding, Chain Length, Branching
• Ranking the amine above the alcohol
  → Solubility in Water and the Kinds of Hydrogen Bond
• Picking o-nitrophenol for the highest melting point
  → p-Nitrophenol Melts Highest: Inter- Versus Intramolecular H-Bonds

Formulas (3)

• Lucas Reagent and the HX Reactivity Order · Lucas test
  $$\text{R-OH} \xrightarrow{\text{conc. HCl / ZnCl}_2} \text{R-Cl}\ (\text{turbid});\quad 3^\circ \text{ instant} > 2^\circ \text{ minutes} > 1^\circ \text{ none}$$
• Dehydration (Saytzeff, With Rearrangement) and Oxidation · Dehydration
  $$\text{R}_2\text{CH-CH(OH)R} \xrightarrow{\text{conc. H}_2\text{SO}_4,\ \Delta} \text{R}_2\text{C=CHR} + \text{H}_2\text{O} \quad (\text{Saytzeff, after any hydride shift})$$
• Alcohols From Grignard Reagents; Acidity of Alcohols and Phenols · Grignard to alcohol
  $$\text{HCHO} \to 1^\circ;\quad \text{RCHO} \to 2^\circ;\quad \text{R}_2\text{CO} \to 3^\circ \quad (\text{then H}_3\text{O}^+)$$

Watch out for (3)

• Marking esterification as C–O cleavage
  → Lucas Reagent and the HX Reactivity Order
• Eliminating from the carbon that carried the OH
  → Dehydration (Saytzeff, With Rearrangement) and Oxidation
• Counting the Grignard carbon into the wrong place
  → Alcohols From Grignard Reagents; Acidity of Alcohols and Phenols

Formulas (3)

• Making Phenol: Cumene and Dow · Cumene route
  $$\text{C}_6\text{H}_5\text{CH(CH}_3)_2 \xrightarrow{\text{O}_2} \text{C}_6\text{H}_5\text{C(CH}_3)_2\text{OOH} \xrightarrow{\text{H}^+} \text{C}_6\text{H}_5\text{OH} + (\text{CH}_3)_2\text{CO}$$
• Nitration and Bromination of Phenol · How far the reaction goes
  $$\text{dil. HNO}_3 \to o/p\text{-nitrophenol};\quad \text{HNO}_3/\text{H}_2\text{SO}_4 \to \text{picric acid};\quad \text{Br}_2(\text{aq}) \to 2,4,6\text{-tribromophenol}$$
• Kolbe, Reimer–Tiemann, Oxidation and Reduction of Phenol · Kolbe and Reimer–Tiemann
  $$\text{ArONa} + \text{CO}_2 \to o\text{-HOC}_6\text{H}_4\text{COONa} \to \text{salicylic acid};\qquad \text{ArOH} + \text{CHCl}_3/\text{NaOH} \to o\text{-HOC}_6\text{H}_4\text{CHO}$$

Reference tables (1)

Watch out for (4)

• Stopping at cumene hydroperoxide
  → Making Phenol: Cumene and Dow
• Trinitrating with dilute acid
  → Nitration and Bromination of Phenol
• Starting Kolbe from phenol itself
  → Kolbe, Reimer–Tiemann, Oxidation and Reduction of Phenol
• Confusing the 1,2,3 and 1,3,5 triol drawings
  → Phenols in Nature: Eugenol, Gallic Acid, Curcumin and the Polyols

Formulas (2)

• Williamson Synthesis: Alkoxide Plus Primary Halide · Williamson synthesis
  $$\text{R-O}^-\text{Na}^+ + \text{R'-X} \xrightarrow{\text{SN2}} \text{R-O-R'} + \text{NaX} \quad (\text{R'X primary; never aryl})$$
• Reactions of Ethers: Oxonium Salts, HI Cleavage, Anisole · Cleavage by HI
  $$\text{Ar-O-R} + \text{HI} \xrightarrow{\Delta} \text{Ar-OH} + \text{R-I} \quad (\text{aryl-O bond survives})$$

Watch out for (2)

• Expecting isobutylene from methyl bromide and tert-butoxide
  → Williamson Synthesis: Alkoxide Plus Primary Halide
• Cleaving the aryl side with HI
  → Reactions of Ethers: Oxonium Salts, HI Cleavage, Anisole