STPM Chemistry Topic 17 Hydroxyl Compound (Short notes)

Chapter 17 Hydroxyl Compound

SMK Sacred Heart, Sibu

1. Preparation of hydroxyl compound (i) LiAlH4 in dry ether, (ii) H3O+, ∆ Na in C2H5OH H2, Ni, 180oC ,(Not suitable for aromatic compounds) (i)NaBH4, ethanol (ii)H3O+, ∆ (For aldehyde & ketone) Alkaline hydrolysis of haloalkanes, R-X + NaOH(aq) +H2O(g), conc H3PO4, 300oC, 60atm Hydration of alkenes, C=C (i) Conc H2SO4, rtp (ii)H2O, ∆ Reduction of C=O bond

Reaction of Grignard reagent

2. Reactions of Aliphatic alcohol

RMgX + H2C=O RMgX + RCH=O RMgX + R’RC=O 2. Reactions of Aromatic alcohol (Phenol)

n e o –w +HX SCl i n e

o

-w

+HX

Na metal, r.t.p R-OH + Na → R-ONa + H2 Esterification (a) RCOOH, ∆, conc H2SO4 (b) RCOCl, rtp Remove H2 A)Oxidation C-OH→C=O Insert O btw C-H KMnO4/H+ 1o → RCOOH 2o → RCOR 3o → No reaction Remove H2 B) Dehydrogenation C-OH→C=O Cu, 300oC 1o → RCHO 2o → RCOR 3o → C=C (Remove H2O) Dehydration Remove H2O (a) Conc H2SO4, 180oC C-OH→C=O (b) Al2O3, ∆ Lucas reagent (Conc HCl, ZnCl2) (a) Conc H2SO4, 180oC (b) Al2O3, ∆ R-OH + HCl → R-Cl + H2O

SCl i

1o → no cloudiness at rtp 2o → cloudiness after 5 min 3o → cloudiness immediately Cl substitution (Conc HCl, ZnCl2) R-OH → R-Cl (a) PCl5 / SOCl2 Iodoform test (I2 in NaOH(aq), warm) H R

C CH3

OH

R

C

O

ONa

+NaOH(aq)

ONa

+Na

ONa

+RCOCl

OCOR

-OH group is Ortho and Para director +Cl2, dry AlCl3 Conc H2SO4, ∆ +RX, dry AlCl3 +RCOCl, dry AlCl3 +HNO3

OH

dilute OH +

Concentrated OH O 2N NO2

NO2

NO2

NO2

Chemical test for phenol

Add Br2(aq) or Cl2(aq) Observation: White solid Br

OH Br

Br Fission of RO-H bond Fission of R-OH bond

neo -w +HX SCl i