Hydroxyl compounds A. Classification: 1. alkanol: primary alcohol (1( alkanol)butan-1-ol secondary alcohol (2( alkanol) butan-2-ol tertiary alcohol (3( alkanol)2-methylbutan-2-ol 2. phenol Classify by number of hydoxyl groups per molecule: 1. monohydric alkanol ethanol 2. polyhydric alkanolethane-1,2-diol B. IUPAC name: [pic][pic][pic] pent-4-en-2-ol3-bromocyclohexanol but-3-yn-1-ol [pic][pic][pic] hex-2-ene-1,6-diol 2-methylphenol1,4-dihydroxybenzene o-methylphenol p-dihydroxybenzene C. Preparation: Industrial process: 1. Fermentation of carbohydrates: [pic] 2.
Hydration of alkene: [pic] 3. Formation of methanol: [pic] Laboratory method: 1. Nucleophilic substitution: [pic] 2. Reduction of carbonyl compounds a. By lithium tetrahydrioaluminate LiAlH4: Li AlH4 in ether is a strong reducing agent which can reduce acid, ester, carbonyl group (containing O atom) but not alkene and alkyne. [pic] b. By hydrogenation: Hydrogenation can also be used to convert alkene and alkyne to alkane. [pic] 3. Oxidation of alkenes: Oxidize alkene by strong oxidizing agent, acidified potassium permanganate. [pic] Phenol: 1. Sulphonation [pic][pic] 2. Diazo salt pic] 3. Physical properties of alkanol: a. Intermolecular H-bond b. High boiling point, melting point and solubility in water 4. Chemical properties of alkanol: Principle of reaction: R(O(H Breakage of C(O bond to form C+ ion Breakage of O(H bond to form R(O( ion Favour stable carbonium ion favor 1((alkanol or R with electron withdrawing group a. Intramolecular dehydration (Elimination, alkene formation) By dehrating agent: Condition: high temperature 180(C, Conc. sulphuric acid, mole ratio of alkanol:acid = 1:1 [pic] By catalyst:
Condition: Aluminium oxide as catalyst, 350(C [pic] b. Intermolecular dehydration Condition: high temperature 140(C, Conc. sulphuric acid, mole ratio of alkanol:acid = 2:1 [pic] c. Halogenation Lucas Test: [pic] Reagent: zinc chloride + Conc. HCl Procedure: Mix the Lucas reagent with alkanol; observe the rate of the appearance of the turbidity. (Chloroalkane oil droplets are insoluble in aqueous phase. ) Result: Turbidity forms immediately. 3( alkanol Turbidity forms slowly (5 minutes). 2( alkanol Turbidity does not form. ( alkanol Other reagents for halogenation: PX3, PX5, SOCl2 [pic] [pic] white fumes [pic] d. React with sodium [pic] sodium methoxide, a strong organic alkali Application of sodium alkoxide: Formation of ether: [pic] Formation of alkene: [pic] e. Esterification (Condensation) [pic] ethyl ethanoate f. Oxidation Oxidizing agents: KMnO4/H+/neutral/OH( Mild oxidizing agent: CuO [pic] aldehyde Strong oxidizing agent: KMnO4/H+ [pic] acid Different alkanols are refluxed with acidified potassium permanganate: Primary alkanol: [pic] Secondary alkanol: pic] ketone Tertiary alkanol: [pic] g. Haloform reaction (Iodoform test) [pic] iodoform, yellow solid 5. Physical properties of phenol: Colouless solid (slightly pink) at room temperature, high vapour pressure at room temperature, slightly soluble in water, highly toxic, high melting point and boiling point due to intermolecular hydrogen bonding 6. Chemical properties of phenol: a. Acidic [pic] phenoxide ion Reasons: O in phenol becomes slightly electron deficient [pic] Phenoxide ion is stabilized by resonance effect [pic]
React with NaOH: [pic] [pic] b. Act as nucleophile in nucleophilic substitution [pic] [pic] [pic] c. Electrophilic substitution Phenol is an activating group, o,p-directing, explain by resonance effect Nitration: [pic] major [pic] 2,4,6-trinitrophenol (a kind of explosive) Halogenation: [pic] a product in the experiment involving rate order Sulphonation: [pic] benzenesulphonic acid d. Complex formation React with iron (III) ion to form a blue/violet coloration. [pic]