• Phenol also named as carbolic acid & hydroxybenzene

• Industrial preparation of phenol

I) From coal tar distillation $\rightarrow$ light oil,middle oil,heavy oil $\rightarrow$ Phenol,Naphthalene

• Middle oil $\rightarrow$ pure phenol boiling point (180-182°C)

II) From chloro benzene $\rightarrow$ (Dow’s process)

III) From cumene (isopropyl benzene)

IV) From sulfonic acid: Alkali fusion of sulfonate

• $ArSO_2OH+NaOH \rightarrow ArSO_2ONa$ (Sodium aryl sulfonate)$+H_2O$

• $ArSO_2ONa \xrightarrow [{300^oC}]{NaOH / H_2O} ArONa+Na_2SO_3$

• $ArONa \xrightarrow {dil. H_2SO_4}ArOH+Na_2SO_4$

V) Hydrolysis of diazonium salts:

• $ArN_2^+X^- +H_2O \xrightarrow [{\Delta}]{dil. acid} ArOH+N_2 \uparrow +HX$

• $C_6H_6 \xrightarrow{NO_2^+} C_6 H_5 NO_2$ $\xrightarrow [{HCl}]{SnCl_2} C_6H_5NH_2$ $\xrightarrow {HCl 0-5^oC } { NaNO_2}$

• $C_6H_5N_2^+Cl^- \xrightarrow {H_2O / \Delta} C_6H_5OH+N_2 \uparrow +HCl$

VI) From Grignard’s Reagent +air $\xrightarrow [{by}] {followed}$ dil. acid hydrolysis

• $C_6H_5MgX+\frac{1}{2}O_2 \rightarrow C_6H_5OMgX \xrightarrow [{H^+/H_2O}] C_6H_5OH+Mg(OH)X$

• $C_6H_5-O-H——O-H-H_5C_6$ (Hydrogen bonding)

• Physical properties

• Colourless liquids or low-melting solids phenol melting point is 43°C & boiling point is $182^oC$

• Carbolic odour

• Moderately soluble in water

• Soluble in organic solvents

• Get oxidized easily

(I) Due to OH group

(II) Due To aryl nucleus

(I) Due to OH group

(A) Resemble alcohols

(B) Do not resemble alcohols

(A) Resemblance to alcohols-(H-is replaced)

(ii) Acyclation: $RCOCl, (RCO)_2O \rightarrow$ phenyl esters

$CH_3-CO-Cl+C_6H_5-O-H \xrightarrow {Py} C_6H_5-O-CO-CH_3 (phenyl \hspace{1mm} acetate)+HCl$

(iii) Benzoylation: $C_6H_5COCl$ in $aq. NaOH$ (SCHOTTEN-BAUMANN REACTION)

$C_6H_5COCl+H-O-C_6H_5 \xrightarrow {NaOH} C_6H_5-CO-O-C_6H_5 (phenyl \hspace{1mm} benzoate)+NaCl+H_2O$

(iv) With benzene sulfonyl chloride - Tosylates

$C_6H_5SO_2Cl+HOC_6H_5 \rightarrow C_6H_5SO_2OC_6H_5+HCl$ (Tosylates phenge benzene sulfonate)

(v) With alliye halides: WILLIAMSON’S SYNTHESIS

Formation of allyl anyl ethers Nuc. Sub. Кап

$C_6H_5O^-Na^++ClCH_3 \xrightarrow [{aq.}]{NaOH} C_6H_5OCH_3(anisole)+NaCl$

• $H_2C-H_2C-H_2C-O-C_6H_5 (phenyl-n-propyl \hspace{1mm} ether) \leftarrow CH_3CH_2CH_2Br+Na^+O^–C_6H_5$

• $H_2C-H_2C-H_2C-O-C_6H_5 (phenyl-n-propyl \hspace{1mm} ether) \leftarrow CH_3CH_2CH_2O^-Na^++Br-C_6H_5$ (low reactivity towards SN.)

• OH gp is replaced

(VI) $PCl_5$

$C_6H_5-OH-(NO_2)_2 \xrightarrow {PCl_5} C_6H_5-Cl-(NO_2)_2+POCl_3+HCl$

• Nuc sub on angl rasing is v.sl

(VII) Ammonia : heat at ~250c in presence of anhydrous $ZnCl$

• $C_6H_5OH+HNH_2 \xrightarrow [{angl. ZnCl_2}]{-H_2O, 250^oC} C_6H_5NH_2+H_2O$

(B) Phenols don’t resemble alcohale OH gp is attached to angle core (1) Action of $FeCl_3$ coln

• violet, green, purple, red color

• due to formation formation of of ferric complexes

• $-C(OH)=C-(enols)$ $C_6H-5-OH$ | +ve $FeCl_3$ test

(ii) With zinc dust heat $\rightarrow$ arenes as product $C_6H_5OH \xrightarrow [{\Delta}]{Zn} C_6H_6+ZnO$

(iii) Acidic nature of phenols(Pha in $H_2O$ at $25^oC$) $\rightarrow$ blue litmus Red, Dissolves in alkali, No effervesence with $NaHCO_3$ soln

$RCOOH>ArOH(Weak \hspace{1mm} acid)>ROH$ (million times more acidic)

$C_6H_5-OH (Weak \hspace{1mm} acid)+H_2O \rightleftharpoons C_6H_5-O^-+H_3^+O$

$C_6H_5- \ddot O:-H \leftrightarrow C_6H_5-O^+H \leftrightarrow C_6H_5-O^+ \leftrightarrow C_6H_5=O \leftrightarrow —-$

(i) Hydrogenation $\rightarrow H_2 / Ni, \triangle \rightarrow$ cycloalkanols

(ii) Electrophilic substitution reaction

${}^{-}OH -$ activating gp$\left\{\begin{array}{l} O^{-} \\ P^{-} \end{array}\right.$

(a) Halogenation

• $Br_2$ (bromate - bromide method)

• Water (potassium bromate + potassium bromide)

• Lewis acid is not neq for bromination

(b) Sulfonation

(C) Nitration 4 poor yield of products because of oxidation of S.M. asa sodium

• $SO_3H$ - good leaving gp

• Deactivates benzene nucleus. & prevents oxidate

• Easily replaced by $NO_2$

(d) Friedel Craft’s alkylation $RX/AlCl_3 \rightarrow$ alkyl phenols