Chapter 12 Hydroxy Compounds (Alcohals, Phenols) and Ethers Part 1 – Chemistry free study material by TEACHING CARE online tuition and coaching classes

 

 

Hydroxy compounds are compounds in which the hydroxy group, – OH is directly linked with the aliphatic or aromatic carbon. Hydroxy compounds can be classified into following three categories.

• Aliphatic hydroxy compounds (alcohols) : Alcohols are regarded as hydroxy derivatives of

 

R – H

¾¾^–¾^H ® R – OH

(R = alkyl group)

 

Hydrocarbon

+OH

Alcohol

 

They can be mono, di or tri-hydric alcohols depending upon whether they contain one, two or three hydroxy groups.

Monohydric alcohols	Dihydric alcohol	Trihydric alcohol	Polyhydric alcohol
CH3OH Methanol  C2H5OH Ethanol	CH2OH | CH2OH Glycol	CH2OH | CHOH | CH2OH Glycerol	CH2OH | (CHOH)4 | CH2OH sorbital or Mannitol

• Aromatic hydroxy compounds (Phenols) : Phenols are regarded as hydroxy derivatives of aromatic hydrocarbons (arenes).

Ar – H ¾¾^–¾^H ® Ar – OH

 

Arene

+OH

Phenol

 

They can be mono, di or tri-hydric phenols depending upon whether they contain one, two or three hydroxy

 

groups.

 

Monohydric phenols :

OH

 

 

Phenol

OH

 

 

o-cresol

CH₃

OH

 

 

m-cresol

 

 

CH₃

OH

 

 

 

CH₃

 

 

 

Dihydric phenols :

 

 

 

 

Trihydric phenols :

OH

OH

 

 

Catechol

 

OH

OH

OH

 

 

OH

Resorcinol

 

OH

OH

OH

 

 

 

OH

OH  Quinol

p-cresol

 

OH

Pyrogallol

OH

Hydroxy quinol

HO Phloroglucinol OH

 

• Aromatic alcohols : Compounds in which the hydroxy group is present in the side chain are termed aromatic

 

CH₂OH

 

 

Benzyl alcohol

CH₂CH₂OH

 

 

2 phenyl ethanol

 

 

 

Alcohols containing one hydroxyl group are known as monohydric alcohols. These alcohols may be saturated or unsaturated depending on the nature of hydrocarbon groups. Saturated monohydric alcohols form a homologous

 

series of the general formula

Cn H 2n+1OH . They are also represented as R – OH where R represents an alkyl group.

 

They may be regarded as derivatives of water, i.e., one hydrogen atom of the water molecule is replaced by an alkyl group.

HOH ¾¾^–¾^H ® R – OH

Water        + R                Alcohol

• Classification : Monohydric alcohols are subdivided into three classes
  • Primary alcohols : In these alcohols, the hydroxyl group is attached with primary (1^o ) carbon They

 

possess a characteristic group – CH ₂OH

and their general formula is

RCH ₂OH . R may be H in the first member

 

and alkyl group in the rest of the members.

 

 

Examples : HCH

₂OH ; CH

₃CH

₂OH ; CH

₃CH

₂CH

OH ; CH3

²       CH

CH – CH

₂OH

 

Methyl alcohol

Ethyl alcohol

n-propyl alcohol

3

isobutyl alcohol

 

• Secondary alcohols : In these monohydric alcohols, the hydroxyl group is attached with secondary (2°)

 

carbon atom. They possess a characteristic group        CHOH and the general formula R

R¢

same or different).

CHOH

(R and R¢ may be

 

Example : CH3OH

CH3OH

CHOH ; C2 H5

CH3

CHOH

 

Isopropyl alcohol                      sec. butyl alcohol

• Tertiary alcohols : In these monohydric alcohols, the hydroxyl group is attached with tertiary (3°) carbon

R¢¢

 

atom. They contain a characteristic group          COH and have the general formula

 

same or different).

R¢    OH R

(R, R¢ and R¢¢ may be

 

CH3

|

CH3

|

 

Examples : CH 3 – C– OH ; C2 H 5  – C– OH

 

|

CH3

tert. Butyl alcohol

(2)  Nomenclature

|

CH3

tert. Amyl alcohol

 

• Common system : Named as alkyl

Note : ® In higher members, it is always indicated whether the – OH group is attached to primary, secondary and tertiary carbon. By prefixing n for primary sec. for secondary and tert. for tertiary.

CH3

|

Example :  CH 3 CH 2 OH ;  CH 3  – CH 2  – CH – CH 3 ;  CH₃ – C– OH

 

Ethyl alcohol

|

OH

sec. butyl alcohol

|

CH3

tert. butyl alcohol

 

• Carbinol system :

CH 3 OH

is called carbinol. All other members are considered its alkyl derivatives.

 

 

 

Example : CH  OH ; CH3          CHOH ;  CH3

CHCH OH

 

3

Carbinol

CH3

CH3                       2

 

Di methyl carbinol

• IUPAC system : Named as

Isopropyl carbinol

 

Example  :  CH 3 OH  ;  CH3CH2CH2OH ;  CH3CH2CH2CH2OH

 

Methanol

Propanol -1

Butanol -1

 

• Structure : Oxygen of – OH group is bonded to

sp³

hybrid carbon by a sigma bond.

 

 

 

 

 

 

 

 

 

 

 

 

(4)  Isomerism

 

• Chain isomerism :

 

 

 

 

 

 

 

 

CH3

|

CH3CH2CH2CH2OH « CH3 – CH– CH2OH

 

Butanol -1                                2 Methyl propanol -1

 

• Positional isomerism :

CH3 CH 2 CH 2 OH « CH3 CH CH3

 

Propanol-1

|

OH

Propanol-2

 

• Functional isomerism :

CH3CH2OH  «  CH3OCH3

 

Ethanol                Methoxy methane

(5)  General methods of preparation of monohydric alcohols

 

• From alkyl halide :

C2 H5 Br +

Bromoethane

KOH

(Aqueous)

® C2 H5OH+ KBr ;

Ethanol

C2 H5 Br

Bromoethane

+     AgOH       ®

Moist silver oxide

C₂H₅OH+ AgBr

Ethanol

 

Note : ® 1° alkyl halide gives good yield of alcohols.

• 2° alkyl halide gives mixture of alcohol and
• 3° alkyl halide gives alkenes due to

 

CH3

|

CH₃ – C– CH₃ +

|

Br

KOH

(Aqueous)

CH3

|

® CH₃ – C = CH₂ + KBr + H₂O

• Methylpropene (Major product)

 

• Oxidation number of carbon in different organic compounds are given below in increasing order,

¾¾Alk¾an¾e,¾al¾ken¾e,¾al¾ky¾ne¾, al¾ky¾l h¾ali¾de¾, al¾co¾ho¾l, c¾ar¾bo¾ny¾l co¾m¾po¾un¾ds¾, a¾cid¾s a¾n¾d a¾cid¾d¾eri¾va¾tiv¾e¾s ®

Oxidation number of carbon in increasing order

• Alkanes and alkenes can be converted into alcohols by oxidation method while carbonyl compounds, acid and their derivatives can be converted into alcohol by
• Oxidation of carbon in RX and ROH is same hence RX converts into R–OH by displacement reaction.

 

 

 

 

• From alkenes

• Hydration

Direct process :

 

 

C = C

 

 

 

|      |

HOH

¾¾¾® –     –    –

 

C C

Alkene                               |      |

 

 

Indirect process :

OH H

Alcohol

CH2  = CH2 + HOSO2OH ® CH3 CH2OSO2OH ¾¾^H2¾^O ® CH3 CH2OH+ H2 SO4

 

Ethene

Sulphuric acid

Ethyl hydrogen sulphate

Boil

Ethanol

 

In case of unsymmetrical alkenes

CH3 CH  = CH 2 + HOSO2 OH ¾¾^Mar¾^kow¾^niko¾^f¾^f”s ® CH3  – CH– CH3  ¾¾^H2¾^O ® CH3  – CH – CH3

 

Propene

CH3

rule

|

OSO2OH

CH3

Boil

|

OH

Propan-2-ol

CH3

 

|

• = CH

+ H ⁺ ¾¾^{H S}¾^O¾®

|

• – CH

¾¾^H¾^O ®

|

• – CH

 

3

2

3

C                                     2      4                                     C                       2                                      C

Å                                                                            |

 

• Oxymercuration-demercuration

OH

Alcohol

 

C = C

• H O + Hg(OAc)

Oxymercuration              |      |           NaBH

–  C– C–

 

¾¾¾¾¾¾® –   –    – ¾¾¾¾4  ®

2                            2

Mercuric acetate

C  C

|       |           Demercuration       |      |

 

OH HgOAc

OH H

Alcohol

 

This reaction is very fast and produces the alcohol in high yield. The alcohol obtained corresponds to Markownikoff’s addition of water to alkene.

• Hydroboration oxidation (HBO) : (Antimarkownikoff’s orientation)

 

C = C

• H – B

|      |                                     |      |

–

H2O2 , OH                          –   –

 

® – C – C– ¾¾¾¾¾® – C   C

|      |                                     |      |

H   B                                   H OH

Alcohol

Diborane is an electron defficient molecule. It acts as an electrophile reacting with alkenes to form alkyl boranes

R3 B .

R – CH = CH 2  + H – BH 2  ® R – CH – C H 2  ¾¾^RCH¾^=C¾^H¾2  ®(R CH 2  CH 2 )2  BH ¾¾^RCH¾2 =¾^CH¾2  ®(RCH 2 CH 2 )3 B

 

|           |

H        B H2

Dialkyl borane

Trialkyl borane

 

Alkyl borane

 

 

 

Other examples :

(B₂H₆)                               (CH₂ – CH₂)₃B ¾¾¾H¾2O  ¾¾®

Antimarkownikoff’s rule

 

 

 

• Alkanol

CH₂ – CH₂OH

 

CH –––– CH₂

|                     |

OCOCH₃ HgOCOCH₃

¾¾¾^H¾+       ¾®

Markownikoff’s rule

CH – CH₃

|

OH

• Alkanol

 

 

Å

CH₂ – CH₃

        Å

CH – CH₃

¾¾^H2¾^O ®

CH₂ – CH₃ OH

 

 

Less stable

 

Note : ® Carbocation are not the intermediate in HBO hence no rearrangement take place.

• By reduction of carbonyl compounds : Bouveault Blanc

 

 

RCHO  + H ₂ ¾¾^P¾^d ® RCH ₂OH ;         RCOR¢+ H 2  ¾¾^NaB¾^H¾4  ® R – CH – R¢

 

Aldehyde

LiAlH4

Primary alcohol

Ketone

or Ni / Pt

|

OH

Secondary alcohol

 

 

 

 

CH₂               CH₂

H₃O⁺

CH₃    Å

Å           CH₃

¾¾^H¾2O ® CH3

HO

CH₃ OH

 

HO – CH₂                CH₂OH

 

 

LiAlH4

also reduces epoxides into alcohol :

CH2 – CH2 + LiAlH4 ® CH3 – CH2OH O

 

Hydride selectively attacks the less alkylated carbon of the epoxide.

 

 

CH3

CH3

|

• C– CH

O

¾¾^LiA¾^lH¾4  ® CH H –                      H +                   3

CH3

|

• C– CH3

|

OH

 

• By reduction of carboxylic acids and their derivatives

 

R – COOH ¾¾^{(i) L}¾^iAlH¾4  ® RCH 2 OH ;

RCOOH

® RCOOR¢ ¾¾^H¾2  ® RCH 2 OH + R¢OH

 

Carboxylic acid

• H₂O

primary alcohol

Carboxylic acid

Ester

Catalyst

 

Esters are also reduced to alcohols

 

(Bouveault Blanc reaction) CH

 

O

||

• – OCH

 

 

• 4[H] ¾¾^{Na /}¾^C2 ¾^H5 O¾^H ® CH CH  OH + CH  OH

 

3      C                3

3        2                   3

 

Methyl acetate (Ester)

Ethanol

Methanol

 

Note : ® Reduction with aluminium isopropoxide is known as Meerwein-Ponndorff verley reduction (MPV) reduction.

 

Me2

C = O + (CH₃ )₂

CHOH ¾¾^Al(O¾^CH¾^Me¾2 ) ® Me

CHOH + CH3

²            CH

C = O

 

Isopropyl alcohol                                                                           3

O                                                           O

||                                                            ||

• By hydrolysis of ester : R – C– OR¢+ HO / Na(aq) ® R – C– ONa + R¢OH .

Sod. salt of acid             Alcohol

 

• From primary amines :

CH3 CH2 NH2 + HONO ¾¾^NaN¾^O2¾^{/ H}¾^Cl ® CH3 CH2OH  + N 2  + H2O

 

Aminoethane                                                               Ethanol

Note : ® It is not a good method of preparation of alcohols because number of by product are formed like alkyl chloride alkenes and ethers.

• From Grignard reagent

 

• With oxygen :

2R – Mg – X + O2  ¾¾^D ® 2R – O – Mg – X ¾¾^2HO¾¾^H ® 2ROH + 2Mg(X)OH

Al2O3

 

• With ethylene oxide

 

 

 

d +               d +

R^{d –} – Mg^{d +} – X + CH2 – CH2  ® RCH 2CH2  – OMgX ¾¾^H2¾^O ® RCH 2CH2OH + Mg(X)OH Od –

 

Other examples

With cyclic ester

O

+ CH₃Mg – Br ®

 

OMgBr CH₃ CH₃

 

HO

H₂O

 

OH

C CH₃ CH₃

 

 

 

Cl                               Br

+  Mg ® Cl                               Mg Br

¾¾^CH¾2¾^O ® Cl                              CH₂OMg Br

 

 

 

 

Cl                              CH₂OH

 

H                        H                                       H

d –              d +                                       |                           |                                          |

 

• With carbonyl compounds :

R ¬ Mg– X + R¢ – C^{d +}

||

Od –

® R¢ – C – R

|

OMgX

¾¾^H2¾^O ® R¢ – C – R

|

OH

 

Note : ® If R¢ = H, product will be 1°alcohol.

• If R¢ = R, product will be 2°alcohol.
• If carbonyl compound is ketone, product will be 3°
• It is the best method for preparation of alcohol because we can prepare every type of
  • The oxo process : It is also called carbonylation or hydroformylation reaction. A mixture of alkene carbon monoxides and hydrogen. Under pressure and elevated temperature in the presence of catalyst forms

 

Catalyst is cobalt carbonyl hydride

[CoH(CO)₄ ]

product is a mixture of isomeric straight chain (major) and

 

branched chain (minor) aldehydes. Aldehydes are reduced catalytically to the corresponding alcohols.

CH₃ – CH – CHO

3

|

 

 

2CH3 – CH = CH 2 + 2CO + 2H 2  ® CH3 – CH 2 – CH 2 – CHO

CH₃             CH

– CH – CH₂OH

|

CH₃

 

 

(6)  Physical properties of monohydric alcohols

H₂

Zn – Cu

CH₃ – CH₂ – CH₂ – CH₂ – OH

 

• Character : Alcohols are neutral These have no effect on litmus paper. This is analytical test for alcohols.
• Physical state : The lower alcohols (upto C₁₂) are colourless alcohol with characteristic smell and burning The higher members with more than 12-carbon atoms are colourless and odourless solids.
• Polar character : Oxygen atom of the – OH group is more electronegative than both carbon and Thus the electron density near oxygen atom is slightly higher. Hydrogen bonding shown below

 

 

 

H – O– – – –H – O– – – H – O—– H – O . This gives polar character to OH bond.

|                     |                   |                     |

R                   R                  R                   R

 

• Solubility : The lower alcohols are miscible in

 

H – O :^{d –} – – – – –^{d +} H – O :         Solubility µ               1

|                                     |                                             Size of alkyl groups

R                                   H

 

Increase in carbon–chain increases organic part hence solubility in water decreases. Isomeric 1°, 2°, 3° alcohols have solubility in order 1° > 2° > 3°.

• Boiling points : Due to intermolecular hydrogen bonding boiling points of alcohols are higher than hydrocarbon and

 

 

B.P. µ

1

 

No. of branches

 

; B.P. follows the trends : 1° alcohols > 2° > 3° alcohol

 

• Density : Alcohols are lighter than Density µ Molecular masses.
• Intoxicating effects : Methanal is poisonous and is not good for drinking It may cause blindness and even death. Ethanal is used for drinking purposes.

• Chemical properties : Characteristic reaction of alcohol are the reaction of the – OH The reactions of the hydroxyl group consists of either cleavage of C – O bond or the cleavage of O – H bond.

 

|

– Cd +

|

d –

® O ¬ H^{d +}

Polar bond

 

C – O bond is weaker in the case of tertiary alcohols due to +I effect of alkyl groups while – OH bond is weaker in primary alcohols as electron density increase between O – H bond and hydrogen tends to separates as a proton.

 

H weaker bond

|

R ® C – O – H    ;

|

H

Primary

R      CH – OH ;

R

Secondary

R

R C – O – H R   weaker bond Tertiary

 

 

Thus primary alcohols give the most of reaction by cleavage of O – H bond while tertiary alcohols are most reactive because of cleavage of C – O bond. Hence – O – H cleavage reactivity order : Primary > Secondary >

Tertiary and C – O – cleavage reactivity order : Tertiary > Secondary > Primary alcohol

• Reaction involving cleavage of with removal of ‘H’ as proton

Alcohols are stronger acids than terminal acetylene but are not acidic enough to react with aqueous NaOH or

 

KOH. Acidic nature is in the order

HOH > ROH > CH º CH > NH ₃ > RH .

 

Acidic nature of alcohol decrease with increase of alkyl groups on – OH bonded carbon due to +I (inductive) effect of alkyl group.

 

 

 

 

H

|

R ® – C – O

|

H

R

¯

H > R ® C – O

|

H

R

¯

H > R ® C– O            H

­

R

 

• Reaction with Na : (Active metals)

2RO – H + 2M ® 2ROM + H ₂ (M = Na, K, Mg, Al, etc.)

Evolution of H ₂ shows the presence of –OH and reaction show that alcohols are acidic in nature. Alcohols acts as Bronsted acids because they donate a proton to a strong base (: B^– ) .

 

 

Example :

..

R – O– H+ : B^– ®

..

..

R – O :^–

..

• B – H

Conjugate acid

 

Alcohol (acid)

Base

Alkoxide (conjugate base)

 

 

On reaction of alkoxide with water, starting alcohol is obtained.

..          ..

H – O– H + RO : ® R – O – H        +     OH^–

 

..

Acid

..

Base

Conjugate acid

Conjugate base

 

This is the analytical test for alcohols.

• Reaction with carboxylic acid [Esterification] :

 

RCO– OH + H – OR¢

 

  Conc. H₂SO₄

RCOOR¢+ H ₂O

 

acid

Alcohol

Ester

 

When HCl gas is used as catalyst, the reaction is called fischer-speier esterification.

Presence of bulky group in alcohol or in acid decreases the rate of esterification. This is due to steric hinderence

 

of bulky group. Reactivity of alcohol in this reaction is 1^o

• 2^o

• 3^o .

 

• Reaction with acid derivatives : (Analytical test of alcohol)

 

O

||

CH  –    – Cl + H– O – CH  CH

¾¾Pyri¾di¾ne ® CH

O

||

• – OCH CH

• HCl

 

3      C                                      2        3                                3     C                2        3

 

Ethanoyl chloride

Ethanol

 

 

O            O

||             ||

Ethyl ethanoate (Ethyl acetate)

 

O

||

 

Acylation : CH3 – C– O – C– CH3 + H – OCH2 CH3  ® CH3  – C– OCH2 CH3 + CH3 COOH

Acetic anhydride                                                                          Ethyl ethanoate

 

• Reaction with grignard reagents : CH3 OH+ C2 H5 MgBr ® C2 H6 + CH3 OMgBr

 

Methyl alcohol

Ethyl magnesium br omide

Ethane

 

 

d –     d +                                d +         d –

 

• Reaction with ketene :

R – O– H+ CH 2  = C = O ® CH 2  = C – O – R ® CH3 – C– O – R

 

 

 

 

d –     d +

|

H–O

(enol form)

 

d +

||

O

(Keto form)

 

• Reaction with isocyanic acid :

R – O– H+ H – N = C       ® H – N = C – O – R ® H – NH – C– O – R

 

||                                |

Od –                                        OH

||

O

amino ester (Urethane)

 

 

 

 

• Reaction with ethylene oxide :

R – O – H + CH2  – CH2  ® CH2 – CH2  ¾¾^RO¾^H ® CH2 – CH2

 

|             |

O                     OH       OH

– H2O

|             |

OR       OR

 

 

• Reaction with diazomethane :

R – OH + CH 2 N 2  ® R – O – CH3  + N 2

(Ether)

1, 2-dialkoxyethane

 

• Alkylation :

ROH + R¢2 SO4  ® ROR¢ + R¢HSO4

 

| |

 

• Reaction involving cleavage of

• C – OH

with removal or substitution of –OH group

 

| |

• Reaction with hydrogen halides : Alcohols give alkyl halide. The reactivity of HX is in the order of HI > HBr > HCl and the reactivity of ROH is in the order of allyl, benzyl > 3° > 2°> 1°. The reaction follows a nucleophilic substitution

 

Grove’s process :

ROH + HX ¾¾^ZnC¾^l2  ® R – X + H2 O anhydrous D

 

If alcohols react with HI and red phosphorus, alkane will be formed.

C2 H5 OH + 2HI ¾¾^Red¾^P ® C2 H6  + I 2  + H2O heat

Primary alcohols follow SN ² mechanism . R – OH ⁺ + X ^– ® ^{d –} X – – – R – – – OH^{d +} ® R – X + H O

2                                                       2                               2

Protonated

1^o alcohol

In secondary and tertiary alcohols, the SN¹ mechanism operates

H+                                  –H O                         X –

2

R – OH          R – OH⁺    2           R⁺ ¾ ¾® R – X

• Reaction with PCl₅ : ROH + PX₅ ® RX + POX₃ + HX ; X = Cl (Analytical test for alcohols)

 

• Reaction with PCl₃ :

3ROH

• PCl3

® 3RCl+ H₃ PO₃

 

Alcohol

Phosphorus trichloride

Alkyl chloride

Phosphorus acid

 

• Reaction with thionyl chloride [SOCl₂] :

ROH + SOCl2  ¾¾^Pyri¾^di¾^ne ® RCl + SO2  + HCl

 

• Reaction with ammonia :

ROH + NH3  ¾¾^Al2O¾3  ® RNH2  ¾¾^RO¾^H ® R2 NH  ¾¾^RO¾^H ® R3 N

 

360^o C

Primary amine

Al2O3

Secondary amine

Al2O3

Tertiary amine

 

 

• Reaction with HNO : R – OH + HNO

® R – O – N      O+ H  O

 

3

 

 

3

Mechanism : HNO3 ® H ⁺ + NO^–

3                                 O         2

alkyl nitrite

 

–    –

R – O – H + H ⁺ ® R       Å        H ¾¾¾® R^Å ; R^Å + NO^ ® R – O – N    O

 

|

O               – H2O

H

3                                   O

alkyl nitrite

 

• Reaction with H₂SO₄ [Dehydration of alcohol] : The elimination of water from a compound is known as The order of case dehydration is Tertiary > Secondary > primary alcohol. The products of dehydration of alcohols are depend upon the nature of dehydrating agents and temperature.

 

CH₂ = CH₂

–(H⁺)

 

CH 3  – CH 2  – OH ¾¾^H2S¾^O¾4  ®

Ethylene

C₂H₅HSO₄

Ethyl hydrogen sulphate

C₂H₅O – C₂H₅

Diethyl ether

CH3 OH CH3

|        |        |

CH₃ – C – C – C – CH₃

|        |        |

CH3 CH3 CH3

 

Shifting                 +

 

 

 

 

 

 

Alcohol leading to conjugated alkene are dehydrated to a greater extent than those of alcohols leading to nonconjugated alkene. Thus dehydration is in order CH2 = CH – CH – CH3 > CH3 – CH 2 – CH – CH3

 

 

CH3

CH3

|

OH

CH3 CH3

|

OH

CH 3

 

|                                  H SO                                     |

|        |                          –H +                                                        /

 

CH 3  – C – CH – CH 3  ¾¾2 ¾¾4  ® CH 3  – C– CH – CH 3  ® CH 3  – C  – CH – CH 3  ¾¾¾® CH 3  – C = C

 

|       |                          – H₂O                                    |      Å                                                              Å

^|         \ CH

 

CH3 OH

CH3

CH3                 3

Å

2-alkene

 

• CH 2

• CH – CH ₂

|

OH

• CH 3

¾¾^H¾+   ®

H2SO4

–H2O

• CH ₂ – CH– CH ₂ – CH₃

• CH ₂ – CH = CH – CH₃

 

 

• CH = CH – CH ₂ – CH₃

More amount

 

• General reaction of alcohols

 

• Reduction :

R – OH + 2HI ¾¾^D ® R – H

 

• Oxidation : Difference between 1°, 2° and 3°

 

1° ®

RCH ₂OH ® R – C = O ® R – C = O

 

|

H

Aldehyde

|

OH

Carboxylic acid

 

2° ®

R – CH – R¢ ¾¾^CrO¾3  ® R – C– R¢ ¾¾¾^O ¾® RCOOH + CO2  + H 2 O

 

|

OH

Secondary alcohol

CH3

|

||           Drastic conditions

O

CH3

|

 

3° ®  CH3  – C– OH ¾¾^4[O¾^] ® CH3  – C = O ¾¾^4[O¾^] ® CH3COOH+ CO2  + H2O

 

|

CH3

Tert. butyl alcohol (Tertiary)

(Under strong condition)

Acetone (Lesser number of carbon atoms)

(Under strong condition)

Acetic acid (Lesser number of carbon atoms)

 

Note :® 3° alcohols are resistant to oxidation, but on taking stronger oxidising agent they form ketone.

• Catalytic oxidation/dehydrogentaion

H                                                      H

1°        |                     Cu, 573K                                     |

CH3 C – O H ¾¾¾¾® CH3 – C = O+ H 2

 

|

H

Ethanol (Pri. alcohol)

 

CH3

Ethanal (Acetaldehyde)

 

 

CH3

 

2° CH3

|

Cu, 573K

– C – O H ¾¾¾¾® CH₃

|

• C = O + H ₂

 

|

H

2-Propanol (Sec. alcohol)

 

CH3

|

3°

 

 

 

 

 

Cu, 573K

Propanone (Acetone)

 

 

CH3

|

 

CH3 – C– OH ¾¾¾¾® CH3 – C = CH 2 + H 2 O

 

|

CH3

2-Methylpropan-2-ol (Tert. alcohol)

2-Methylpropene (Alkene)

 

This is dehydration process and difference between 1°, 2° and 3°alcohols.

 

 

• Oxidation through Fenton’s reagent : [FeSO4 + H 2 O2 ]

Mechanism

CH3                                                      CH3

 

Fe ⁺² + H  O

• |

® Fe ⁺³ + OH ^– +        ;     CH

• | ·
• + ® CH

+ H O

 

_{2  2}                       O H

₃ – C– CH ₂    H     O H

|

OH

₃ – C– C H 2            2

|

OH

 

CH3

CH3

CH3

CH3

 

|      ·                                         |                                      |                                  |

CH3 – C– CH2 + CH2 – C– CH3 ® CH3 – C– CH2 – CH2 – C– CH3

 

|                                   |

OH                             OH

|                                  |

OH                            OH

 

2, 5-dimethyl hexandiol – 2, 5

 

• Self condensation : Guerbet’s reaction

R

 

R – CH2

• CH2

• OH + H – CH– CH₂

– OH ¾¾^NaO¾^C2¾^H5¾^,D ® R – CH2

• CH 2

|

• CH

• CH 2

• OH

 

|

R

• Reaction with cerric ammonium nitrate :

complex. This is analytical test for alcohols.

higher alcohol

 

Cerric ammonium nitrate + ROH ®

Yellow colour

Red colour solution of

 

• Iodoform test : When a few drops of alcohol are warmed with iodine and KOH yellow precipitate of

 

iodoform with characteristic smell is obtained. Any alcohol consists CH₃ CHOH

Example : CH3 CH 2 OH , CH3  – CHOH – CH3 , C6 H5  – CHOH – CH3

group give iodoform test.

 

Since reaction takes place with alkali solution as one of the reagents hence alkyl halide like CH₃ – CH ₂Cl

and

 

CH₃ – CH– R

|

Cl

will also give this test.

 

2NaOH + I 2 ® NaI + NaOI + H 2 O ;  CH3 CH 2 OH + 2NaOI ® CH3 CHO + 2NaOH + 2HI

 

CH3 CHO + 3NaOH ® CI 3 CHO + 3NaOH ;

CI 3 – CHO + NaOH ® CHI 3 + HCOONa

Iodofiorm

 

 

CI 3 – CHO + HCl ® CHI 3 + HCOOH

 

 

Other example

CHOH – CH₃

 

(O)

COCH₃

 

KOH/I₂     CHI3 +

COONa

 

 

 

 

O                                                        O

2

CHOHCH₃ I  /NaOH

 

COCH₃

I

2

O

COCI₃

HCl H₂O

O

COOH

+ CHI₃

 

 

• Individual members of monohydric alcohols

 

Methanol

 

 

(i)  Preparation

• By destructive distillation

 

 

Volatile products

Passed into condenser

 

 

Non-volatile residue (Charcoal)

 

 

 

Uncondensed gases (Wood gas)

Distillate allowed to settle

 

 

 

 

Lower coloured layer (Wood tar)

Upper layer (Pyroligneous acid)

Acetic acid 10%, methanol 2.5%

and acetone 0.5%

Passed through milk of lime and distilled

 

 

 

Distillate (Methanol and acetone)

Residue (Calcium acetate)

 

 

 

Fractionally distilled

Distilled with

H₂SO₄

 

 

 

Acetone (impure) (b.pt. 56° C)

Purified by sodium bisulphite

Methanol (impure) (b.pt. 64.5° C)

Purified by anhydrous Calcium chloride

CH₃COOH

Acetic acid

 

 

 

• From water gas :

C + H

O ¾¾¹³⁰¾⁰o¾^C ® CO + H   ;

CO + 2H 2

¾¾^ZnO¾^+C¾^r2O¾3  ® CH

300^o C

₃OH

 

 

2

2

• From natural gas :

water gas

 

2CH4 + O2 ® 2CH3OH

(9:1) by volume

Compressed gases

Methyl alcohol

 

• Physical properties

 

 

 

• It is a colourless liquid and boils at 5° C.
• It is miscible in water, good solvent for fats and
• It is inflammable and burns with a faint luminous
• It has pleasant smell and burning
  • Uses
• For the manufacture of formaldehyde and formaline. CH3 OH ¾¾^K2C¾^r2O¾7 ® CH 2 O + H 2 O
• A 20% mixture of methyl alcohol and gasoline is a good motor
• Use as an antifreeze for automobile
• To denaturate ethyl alcohol, mixture is called methylated
• In the preparation of dyes, medicines and perfumes.

Ethanol

• Preparation
• From Ethylene : C2 H4 + H 2 O ¾¾^H3 P¾^O¾4  ® C2 H5 OH Yield of ethyl alcohol is 95%.

300^o C,70atm

 

 

 

• From acetylene :

CH

|||

+ H 2 O ¾¾H¾2SO¾4 (4¾0%¾)

éCH2

® ê ||

ù

ú ® CH3 CHO

 

CH

Acetylene

1% HgSO₄ , 60^o C

êëCHOH úû

Vinyl alcohol (Unstable)

Acetaldehyde

 

 

CH3CHO + H2  ¾¾^N¾ⁱ  ® C2 H5 OH

 

110-140^o C

Ethyl alcohol

 

 

• Fermentation : This word is given by Fermentation process is exothermic. Ethanol is prepared by molasses and invert sugar molasses is the waste product in sugar industry. It is a mixture of sugar (30%) and invert sugar (32-40%) combine form of glucose and fructose called invert sugar. Temperature should be 25-30°C. low concentration (8-10%) is favourable.

C12 H22O11  + H2O ¾¾ye¾ast c¾e¾ll  ® C6 H12O5 + C6 H12O6  ; C6 H12O6  ¾¾yea¾st c¾ell ® C2 H5 OH + CO2  + H2O

 

invertase enzyme

glucose

fructose

zymase enzyme

 

 

Certain amounts of inorganic compound such as ammonium sulphate, phosphate should be added. Oxygen is necessary for the growth of ferments. Boric acid, mercury salts etc. should not be present in the solution as these retards the fermentation.

 

• From starch :

2(C6 H10 O5 )n + nH 2 O ¾¾dias¾ta¾se ® nC12 H 22 O11 ;

C12 H22O11 + H 2O ¾¾mal¾to¾se ® 2C6 H12O6

 

starch

maltose (wort)

maltose

glucose

 

 

 

2C6 H12O6  ¾¾^zym¾^a¾^se ® C2 H6 OH + CO2  + H2O + energy

By this method ethanol prepared is 10-12% called wash. Raw spirit

¾¾Frac¾tion¾al ® C2 H5 OH+ H2O

 

distillation

95.5%

4.5%

 

rectified spirit

 

 

 

Manufacturing of ethyl alcohol (absolute) from rectified spirit called Azeotrophic distillation.

• Properties : Same as monohydric
• Uses
• In the manufacture of alcoholic
• As a preservative for biological
• As a low freezing and mobile liquid in scientific apparatus such as thermometers and spirit
• In hospitals as an
• As a petrol substitute (power alcohol).

(9)  Interconversion of monohydric alcohols

• Primary alcohol into secondary alcohols

C3 H7 OH ¾¾^SOC¾¾^l2  ® C3 H7 Cl ¾¾^{alc K}¾^O¾^H ® CH 3 CH = CH 2  ¾¾^H¾^Br ® CH 3  CH CH 3  ¾¾^aq. ¾^KO¾^H ® CH 3  CH CH 3

 

Propan-1-ol (1° alcohol)

Propene                                          |

Br

|

OH

Propan- 2-ol (2° alcohol)

 

• Secondary alcohol into tertiary alcohol

 

 

CH  –

OH

|

– CH

¾¾^[¾^O] ®  CH

O

||

–    – CH

¾¾^CH¾3 Mg¾¾^Br ® CH

OMgBr

|

–    – CH

¾¾^H+ ,¾^H2¾^O ® CH

OH

|

–    – CH

 

₃   CH             3

3     C            3

3     C            3

3     C            3

 

Propan-2-ol

(Iso-propyl alcohol) (2° alcohol)

K2Cr2O7 / H ⁺

|

CH3

|

CH3

2-Methtylpropan-2-ol (3°)(tert. butyl alcohol)

 

• Primary alcohol into tertiary alcohol

 

CH3

|

 

H  SO  , Heat

CH3

|

 

HBr

CH3

|

 

1. KOH

CH3

|

 

CH3 CH CH2 OH ¾¾2 ¾4 ¾¾® CH3  – C = CH2  ¾¾¾¾® CH3  – C– CH3  ¾¾¾¾® CH3  – C– CH3

 

2-Methylpropan-1-ol (1°) (Iso butyl alcohol)

Dehydration

Markownikoff’s                | rule   Br

|

OH

2-Methylpropan-2-ol (3°) (tert. butyl alcohol)

 

 

• Lower alcohol into higher alcohol (ascent of series)

CH 3 OH   ¾¾^HI ® CH3 I ¾¾^KC¾^N ® CH3 CN ¾¾⁴⁽¾^H) ® CH3 CH2 NH2  ¾¾^HO¾^N¾^O ® CH3 CH2OH

 

Methanol

(1 carbon atom)

Reduction

Ethanol

(2 carbon atoms)

 

• Higher alcohol into lower alcohol [Descent series]

 

 

 

+

C  H  OH  ¾¾^K2C¾^r2O¾7 , H¾® CH  COOH ¾¾^NaO¾^H ® CH  COONa ¾¾^NaO¾^{H +}¾^Ca¾^O ® CH    ¾¾^C¾^l2 ® CH  Cl ¾¾^aq. ¾^KO¾^H ®   CH  OH

2    5                     [O]                    3                                           3                            Heat                   4                         3                                       3

 

Ethanol

(2 carbon atoms)

Methanol (one carbon atom)

 

• Alcoholic beverages : Liquors used for drinking purposes containing ethyl alcohol as the principal constituent are called alcoholic Besides alcohol, these contain large amounts of water, colouring and flavouring materials. Alcoholic beverages are of two types :
• Undistilled beverages : These are prepared from fruit juices and grains. Those prepared from grapes and other fruit juices are known as wines. Wines contain 18-20% of ethyl alcohol and are used as such after fermentation, e., with distillation. The natural wines when made stronger by the addition of rectified alcohol are known as fortified wines.

Name	Undistilled	Percentage	of alcohol	Source
Beer	3-6		Barley
Cider	2-6		Apples
Wine (Champagne)	8-10		Grapes
Claret	7-13		Grape juice
Port and Sherry (Fortified)	14-24		Grape juice

• Distilled beverages : These are prepared by the fermentation of molasses, barley, maize, etc. The fermented liquor is then These contain a higher percentage of ethyl alcohol which may be as high as 50%.

Name	Distilled	Percentage	of alcohol	Source
Whisky	35-40		Malt
Rum	45-55		Molasses
Gin	40-45		Maize
Brandy	40-45		Grape juice
Cognac	40-50		Grape juice

• Alcoholometry : The process of determining the percentage of alcohol in a given sample is known as An alcohol water mixture having specific gravity 0.91976 at 15°C and containing 57.1% of ethyl alcohol by volume or 49.3% by mass is called proof-spirit. A sample having higher percentage of ethyl alcohol in comparison to proof-spirit is referred to as over-proof (O.P.) and the one having lower alcohol content than proof- spirit is known as under-proof (U.P.). Thus 15 U.P. means that 100 ml of the sample contains as much alcohol as 85 ml of proof spirit. Similarly, 15 O.P. means that 100 ml of the sample contains as much of alcohol as 115 ml of proof spirit.
• Power alcohol : Alcohol used for the generation of power is called power alcohol. Generally it is a mixture of 80% petrol and 20% absolute alcohol with cosolvent It is cheaply obtained from waste petrol.
• Methylated spirit : Ethyl alcohol containing 5 to 10% of methyl alcohol is known as methylated spirit or denatured spirit. Denaturing can also be done by adding 0.5% pyridine, petroleum naptha, rubber distillate (caoutchoucine) or CuSO₄ .
• Toxicity of alcohols : The toxicity of alcohols is mainly due to their biological to oxidation takes place in living Methyl alcohol is highly toxic and its consumption causes, blindness and death. Ethyl alcohol is non toxic but produces physiological effect disturbing brain activity on drinking. The commercial alcohol is made unfit for drinking by mixing in it copper sulphate (which gives its colour) and pyridine (which makes it foul smelling liquid). It is known as denaturation of alcohol.

 

 

 

(15)  Distinguish between primary, secondary and tertiary monohydric alcohols

 

 

• Lucas test : A mixture of anhydrous

ZnCl ₂ + conc. HCl

is called as Lucas reagent.

 

 

• Victor mayer test : Also known as RBW RBW ® Red, Blue, White test.

Difference between methanol and ethanol

 

 

 

 

• When CH₃OH is heated on Cu coil it gives formalin like
• When CH₃OH is heated with salicylic acid in H₂SO₄ (conc.) then methyl salicylate is formed which has odour like winter green

• It does not give formalin like

 

 

• No such odour is

 

• It does not give haloform or iodoform (iii) It gives haloform test

 

These are compound containing two hydroxyl groups. These are dihydroxy derivatives of alkanes. Their

 

general formula is

Cn H 2n+ 2 O2 . The simplest and most important dihydric alcohol is ethylene glycol. They are

 

classified as a, b, g….. glycols, according to the relative position of two hydroxyl groups. a is 1, 2 glycol, b is 1, 3 glycol.

 

 

 

(1)  Preparation

• From ethylene : (a) Through cold dilute alkaline solution of Bayer’s reagent

|         |

– C = C –

|         |

 

|      |

– C=C –

OH  OH

(Syn-hydroxylation)                                    ;

OH

|       |                         |         |

 

– C – C –

H₂O H+

– C – C –

|         |

OH          OH

 

O                           OH

(Anti-hydroxylation)

 

OH

Alkaline

KmnO₄

 

 

 

cis

OH         Syn-addition (cis)

 

OH

 

Conc. H₂SO₄

 

HCO₃H/H⁺

OH

 

trans          OH

 

CH2      1

 

Catalyst

CH2

H O            CH2OH

 

• With O₂ in presence of Ag : ||

+    O₂ ¾¾¾¾¾® |

O ¾¾2¾®   |

 

CH2      2

Ethylene

Ag,200 – 400°C

CH2

Ethylene oxide

dil. HCl

CH2OH

Ethylene glycol

 

• With HOCl followed by hydrolysis : (Industrial method)

 

CH2

CH2OH

NaHCO

CH2OH

 

||

CH2

• HOCl ®

|

CH2Cl

Ethylene chlorohydrin

¾¾¾¾3  ®|

CH2OH

Glycol

• NaCl + CO₂

 

CH2Br

 

CH2OH

 

• From 1, 2 dibromo ethane [Lab method]:

|

CH2Br

• Na2CO3 + H2O ® |

CH2OH

• 2NaBr + CO₂

 

CH2Br

CH3COOH

CH2OOCCH3

NaOH

CH2OH

 

|           + 2CH₃COOK ¾¾¾¾¾® |

¾¾ ¾® |

• 2CH₃COONa

 

CH2Br

– 2KBr

CH2OOCCH3

Glycol diacetate

CH2OH

 

Note : ® Vinyl bromide is formed as by product.

• Best yield of glycol can be obtained by heating 1, 2-dibromo ethane with CH₃COOK

(2)  Physical properties

• It is a colourless, syrupy liquid and sweet in Its boiling point is 197°C.
• It is miscible in water and ethanol in all proportions but is insoluble in
• It is toxic as methanol when taken
• It is widely used as a solvent and as an antifreeze

in glacial acetic acid.

 

 

 

 

 

 

(3)  Chemical properties

 

 

Na

50°C

 

 

 

PCl₅

 

 

 

PBr₃

CH₂ ONa

|

CH₂ OH

 

CH₂Cl

|

CH₂ OH

 

CH₂Br

|

CH₂ OH

Na

160°C

 

 

 

PCl₅

 

 

 

PBr₃

CH₂ ONa

|

CH₂ ONa

Dialkoxide

CH₂ Cl

|

CH₂ Cl

1,2 Dichloroethane

CH₂Br

|

CH₂Br

 

 

PI₃

 

 

 

HCl

160°C

CH₂I

|

CH₂I

Ethylene iodide

CH₂Cl

|

CH₂OH

I₂

 

 

 

HCl

200°C

CH₂

||

CH₂

CH₂Cl

|

CH₂Cl

 

 

CH₃COOH

CH₂OOCCH₃

CH COOH   CH₂OOCCH₃

 

|

CH₂OH

CH ONO

3                    |

CH₂OOCCH₃

Glycoldiacetate

 

CH₂OH

|

Conc. HNO₃              |    2             2

 

CH₂OH

Conc. H₂SO₄

CH₂ONO₂

Ethylene dinitrate

 

heat 600°C

CH  – CH₂

 

 

 

 

Conc. HNO₃

[O]

 

KMnO₄/H⁺

 

HIO₄ or (CH₃COO)₄Pb

 

Conc. H₂SO₄

O

Ethylene oxide

COOH

|

COOH

Oxalic acid

 

HCOOH

Formic acid

HCHO

Formaldehyde

CH₂ – CH₂ – OH

O

 

 

 

 

 

 

 

CH₂ – CH₂

O

 

CH₂ – CH₂ – OH

Diethylene glycol

CH₂ – CH₂

Dioxane

 

 

Dehydration

ZnCl₂

 

 

CH₃CHO

(HCl)

CH₂

||

CH₂OH

Unstable

CH₂O

|

CH O

Isomerisation

 

 

 

CHCH₃

CH₃CHO

Acetaldehyde

 

 

CH3

O = C

CH

2

Cyclic acetal

C

CH₂O

CH₃

 

3

(HCl)                |

2 Cyclic ketal

CH O               CH3

(1,3 Dioxalane)

 

 

 

 

Dioxalane formation provides a path of protecting a carbonyl group in reaction studied in basic medium in which acetals are not affected. The carbonyl compound may be regenerated by the addition of periodic acid to aqueous solution of the dioxalane or by acidic hydrolysis.

 

R                         C H

C = O + |

R

₂OH ®

O – CH 2

C                |

¾¾^HIO¾4  ® R – CO – R + 2HCHO

 

R                         CH 2 OH         R

O – CH 2

 

Aldehyde is more reactive than ketone in dioxalane formation.

 

O                                                                                 O                                             O

This part does not react due to steric hindrance

 

 

+ CH₂OH – CH₂OH CHO

 

(4)  Uses

H₃C

H ;

C

O         O                          O

CH₃

CH₂ – OH

|

CH₂ – OH

H₃C

CH₃

 

 

 

 

(i) Used as an antifreeze in car radiators.             (ii) Used in the manufacture of dacron, dioxan etc.

(iii) As a solvent and as a preservatives.              (iv) As a cooling agent in aeroplanes.

• As an explosives in the form of

The only important trihydric alcohol is glycerol (propane-1, 2, 3-triol). It occurs as glycosides in almost all animal and vegetable oils and fats.

(1)  Preparation

• From oils and fats

 

CH₂OOCR

|

CH2OH

|

CH₂OOCR

|

NaOH

CH2OH

|

 

CH OOCR + 3H ₂O ® CH OH  + 3RCOOH ; CH OOCR + NaOH ¾¾^Hyd¾^roly¾¾^sis ® CH OH   +

3RCOONa

 

|

CH₂OOCR

Oil or fat

steam

|

CH2OH

Glycerol

Fatty acids

|

CH₂OOCR

Oil or fat

NaOH

|

CH2OH

Sodium salt of higher fatty acids

 

• By fermentation of sugar : C6 H12 C6  ¾¾^Yea¾^st ® C3 H8 O3 + CH3 CHO  + CO2

 

Glucose

• From propene [Modern method]

Na2SO3

Glycerol

Acetaldehyde

 

CH3

CH2Cl

CH2OH

CH2OH

CH2 –OH

 

|                            |

CH    ¾¾^C¾^l2  ®  CH

||            600^o C            ||

¾¾NaO¾H(¾d¾il) ®  |

CH

||

¾¾HO¾Cl  ®

|

CH  Cl

|

¾¾aq. ¾NaO¾H  ® |

CH

|

• OH

 

CH2

propene

CH2

Allyl chloride

CH2

Allyl alcohol

CH2 –OH

b -monochlorohydrin

CH2 –OH

Glycerol

 

 

• From propenal :



CH 2  = CHCHO ¾¾^H¾2  ® CH 2  = CHCH 2 OH ¾¾^H2O¾2 /¾^O¾^H ® HOCH2 CHOHCH2 OH

 

 

(2)  Physical properties

catalyst

Glycerol

 

• It is a colourless, odourless, viscous and hygroscopic
• It has high boiling point e., 290°C. The high viscosity and high boiling point of glycerol are due to association through hydrogen bonding.
• It is soluble in water and ethyl alcohol but insoluble in

 

 

 

• It is sweet in taste and non toxic in

(3)  Chemical properties

 

CH2 –OH

CH2ONa

CH2ONa

 

• Reaction with sodium :

|

CH– OH

|

¾¾^Na¾®

Room

|

CH– OH

|

¾¾^Na¾®

Room

|

CH– OH

|

 

CH2 –OH

• Reaction with PCl₅, PBr₃ and PI₃

temperature

CH2 –OH

Monosodium glycerol

temperature

CH2ONa

Disodium glycerolate

 

 

(a)

CH2OH

|

CH OH

|

CH2OH

• 3PCl5

CH2Cl

|

®    CH Cl

|

CH2Cl

• 3POCl₃ +

3HCl

 

 

CH2OH

|

Glyceryl trichloride (1, 2, 3-Trichloropropane)

CH2Br

|

 

(b) CH OH

|

CH2OH

• PBr3

®    CH Br

|

CH2Br

• H3 PO3

 

1, 2, 3-Tribromopropane

 

CH2OH

éCH2I ù         CH2

 

|

(c)

• PI

® ê |         ú ®    ||          + I

 

CH OH

₃     ê CH I ú        CH               2

 

|                                         ê |         ú        |

 

CH2OH

êëCH2I úû

(Unstable)

CH2I

Allyl iodide

 

• Reaction with HCl or HBr

 

CH2OH

|

CH OH

|

CH2OH

¾¾¹¹⁰o¾^C ®

+ HCl

CH2Cl

|

CH OH      +

|

CH2OH

a -Glycerol monochlorohydrin (66%)

CH2OH

|

CH Cl

|

CH2OH

b -Glycerol monochlorohydrin (34%)

¾¾Exc¾ess o¾f H¾Cl ®

110^o C

CH2Cl

|

CH Cl         +

|

CH2OH

Glycerol

a , b -dichlorohydrin (56%)

CH2Cl

|

CH OH

|

CH2Cl

Glycerol

a ,a ¢-dichlorohydrin (44%)

 

• Reaction with HI

CH2OH

|

CH2I

|

CH2

||

 

(a) CH OH + 3HI

|

CH2OH

¾¾War¾m ®

CH I        ®

|

CH2I

CH       +    I 2

|

CH2I

 

1,2,3-Tri-iodopropane (Unstable)

Allyl iodide

 

 

(b)

CH2

||

CH

|

CH2I

Allyl iodide

• HI ®

CH3

|

CH I

|

CH2I

Unstable

CH3

CH

¾¾^–¾^I2  ® |

||

CH2

Propene

¾¾^H¾^I ®

CH3

|

CH I

|

CH3

Isopropyl iodide

 

• Reaction with oxalic acid

• At 110°C Glycerol is formed

 

 

 

 

CH2OH

|

 

 

 

100-110^o C

CH₂OOCCOOH

|

 

 

 

 

–CO

O

||

CH₂O–C–H

|

CH2OH

H O            |

 

CH OH + HOOC – COOH ¾¾¾¾¾® CH OH

¾¾¾2  ®

CH– OH

¾¾2¾® CH OH + H COOH

 

|

CH2OH

Oxalic acid

–H2O

|

CH2OH

Glycerol mono-oxalate

|

CH2 –OH

Glycerol mono formate

|

CH2OH

Glycerol

Formic acid

 

• At 260°C, allyl alcohol is formed

 

CH2OH

CH2OOC

CH2

 

|                    HOOC

– 2H  O              |

|         -2CO              ||

 

CH OH  +

| ¾¾¾2¾® CH OOC  ¾¾¾¾2  ® CH– CH 2 OH

 

|

CH2OH

HOOC

CH2OH

|

CH2OH

Allyl alcohol

 

 

CH2

 

|

• Dehydration :

||

¾¾con¾c. H¾SO¾/ P¾O ¾/ K¾HSO¾®

• 2H O

 

CH OH

|

CH2OH

2      4     2 5

D

4               CH                     2

|

CHO

Acrolene or allyl aldehyde

 

• Oxidation

 

 

[O]

dil. HNO₃

CHO

|

CHOH      Cl

|

CH₂OH

Glyceraldehyde

COOH

|

CHOH

|

CH₂OH

Glyceric acid

 

 

[O]

COOH

|

CHOH

|

COOH

Tartronic acid

 

 

 

 

CH₂OH

|

CHOH

|

 

Fenton’s reagent

CHO

|

CHOH  +

|

CH₂OH

Glyceraldehyde

CH₂OH

|

C = O

|

CH₂OH

Dihydroxy acetone

 

CH₂OH

 

 

 

[O]

KMnO₄

acidified

 

 

 

 

 

2HIO

CH₂OH

|

CO

|

CH₂OH

Dihydroxy acetone

 

2CH₂O

Glycerose

 

 

 

[O]

CH₂OH

|

CO

|

COOH

Hydroxy Pyruvic acid

 

 

 

2

[O]

COOH

|

CO

|

COOH

Mesoxalic acid

 

[O]        COOH

|

COOH

Oxalic acid

 

[O]      CO

 

+ H₂O

 

D   4                   +

COOH

+ 2HIO₃

+ H₂O

 

 

 

 

• Reaction with nitric acid :

CH2OH

|

CH OH

|

CH2OH

• 3HNO3

CH2ONO2

CH ONO2

¾¾con¾c. H¾2SO¾4  ® |

|

CH2ONO2

• 3H 2 O

 

Glyceryl trinitrate (T.N.G.)

 

 

 

Dynamite is prepared from T.N.G.