Alchohols, Phenols and Ethers

studied byStudied by 40 people
5.0(1)
get a hint
hint

Alcohols and Phenols

1 / 50

51 Terms

1

Alcohols and Phenols

Alcohols and phenols are formed when a hydrogen atom in a hydrocarbon, aliphatic and aromatic respectively, is replaced by –OH group.

New cards
2

Name a substance that can be used as an antiseptic as well as a disinfectant

Phenol : 0.2% solution of phenol is an antiseptic while 2% solution is used as disinfectant.

New cards
3

Classification
i) Based on Number of OH groups

  • Monohydric Alcohols/Alkanols

  • Dihydric Alcohols/Diols

  • Polyhydric Alcohols

New cards
4

ii) Based on Molecular Structure

  • Alkyl Alcohols

    Both α and β carbon are single-bonded

    R-CH₂OH

  • Allyl Alcohols

    β carbon is double-bonded

    CH₂=CH-C(R)(R’)-OH

  • Benzyl Alcohols

    α carbon is attached to the benzene ring/β carbon is part of the benzene ring
    C₆H₆-CH₂OH

  • Vinyl Alcohols

    α carbon is double-bonded

    CH₂=CH-OH

  • Anyl Alcohols

    OH is attached to benzene

    C₆H₅OH

New cards
5

Common and IUPAC Names of Some Alcohols

knowt flashcard image
New cards
6

Preparation of Alcohols

  1. From alkenes

  2. From carbonyl compounds

  3. From Grignard reagents

New cards
7

1.1) From Alkenes - acid catalysed hydration

i) How do you convert Propene to propane-2-ol?

ii) How do you convert 2-methyl-1-pentene to 2-methyl pentan-2-ol?

markonikov’s addition

<p></p><p><em>markonikov’s addition</em></p><p></p>
New cards
8

1.2) From Alkenes - By hydroboration–oxidation

insert how last step works

<p><em>insert how last step works</em></p>
New cards
9

From Carbonyl Compounds (compounds with C=O) and Carboxylic Acids

i) How do you convert Primary alcohol to carboxylic acid?

ii) How do you convert Butan-2-one to Butan-2-ol?

iii) How do you convert ethanol to ethanal?

iv) Draw the structure and name of the product formed if the following alcohols are oxidized:
a) CH₃CH₂CH₂CH₂OH b) 2-butenol c) 2-methyl-1-propanol
Assume that an excess of oxidising agent is used.

1° Alcohol → [O (removal of hydrogen)] Aldehyde → [O (addition of oxygen)] Carboxylic Acid

R-OH → [O] R-CHO → [O] R-COOH

Carboxylic Acid → [H (removal of oxygen)] 1° Alcohol and Aldehyde → [H (addition of hydrogen)] 1° Alcohol

R-COOH → [H] R-OH and R-CHO → R-OH

carboxylic acids cannot directly be reduced to aldehydes

2° Alcohol → [O (removal of hydrogen)] Ketone

R-CH(OH]-R’ → [O] R-C(O)-R’

Ketone → [H (addition of hydrogen)] 2° Alcohol

R-C(O)-R’ → [H] Ketone

New cards
10

2) From Carbonyl Compounds

i) By reduction of aldehydes and ketones:

RCHO → [H-Pd] RCH₂OH

RCOR’ → [NaBH₄] R-CH(OH)-R’

ii) By reduction of carboxylic acids and esters:

RCOOH → [LiAlH₄,H₂O] RCH₂OH

However, LiAlH4 is an expensive reagent, and therefore, used for preparing special chemicals only. Commercially, acids are reduced to alcohols by converting them to esters, followed by their reduction using hydrogen in the presence of a catalyst (catalytic hydrogenation).

reaction in image
insert explanation here

<p>i) By reduction of aldehydes and ketones:</p><p>RCHO → [H-Pd] RCH₂OH</p><p>RCOR’ → [NaBH₄] R-CH(OH)-R’</p><p>ii) By reduction of carboxylic acids and esters:<br><br>RCOOH → [LiAlH₄,H₂O] RCH₂OH</p><p>However, LiAlH4 is an expensive reagent, and therefore, used for preparing special chemicals only. Commercially, acids are reduced to alcohols by converting them to esters, followed by their reduction using hydrogen in the presence of a catalyst (catalytic hydrogenation).<br><br><em>reaction in image</em><br><em>insert explanation here</em></p>
New cards
11

3) From Grignard Reagents

i) Give the structure and IUPAC name of the product formed when propanone is reacted with methyl magnesium bromide followed by hydrolysis.

ii) How are the following alcohols prepared by the reaction of a suitable grignard reagent on methanal

a) 2-Methly Propanol b) C6H5CH2OH

Formaldehyde → [Grignard Reagent, H3O+] 1° Alcohol

Aldehyde → [Grignard Reagent, H3O+] 2° Alcohol

Ketone → [Grignard Reagent, H3O+] 3° Alcohol

<p>Formaldehyde → [Grignard Reagent, H3O+] 1° Alcohol</p><p>Aldehyde → [Grignard Reagent, H3O+] 2° Alcohol</p><p>Ketone → [Grignard Reagent, H3O+] 3° Alcohol</p>
New cards
12

Preparation of Phenols

  1. From haloarenes

  2. From benzenesulphonic acid

  3. From diazonium salts

  4. From cumene

New cards
13

1) From Haloarenes (Dow’s Process)

note has simpler reaction

<p><em>note has simpler reaction</em></p>
New cards
14

2) From Benzenesulphonic Acid

Oleum - fuming sulphuric acid

H2S2O7 (or) H2SO4(SO3) (or) H2SO4 heating

<p>Oleum - fuming sulphuric acid</p><p>H2S2O7 (or) H2SO4(SO3) (or) H2SO4 heating</p><p></p>
New cards
15

3) From Diazonium Salts

i) How do you convert Aniline to phenol?

note has simpler reaction

<p><em>note has simpler reaction</em></p>
New cards
16

4) From Cumene

note has simpler reaction

<p><em>note has simpler reaction</em></p>
New cards
17

Physical Properties

  • The boiling point of alcohols and phenols increases with the increase in molecular mass due to an increase in van der Waal’s forces

  • Isomeric alcohols show a decrease in boiling point with an increase in branching. This is because branching decreases surface area which in turn decreases van der Waal’s forces

  • Alcohols have higher boiling points than ethers, haloalkanes and hydrocarbons of comparable masses due to the presence of intermolecular hydrogen bonding

  • Alcohols are soluble in water as they form hydrogen bonds with the water molecules. Their solubility decreases with an increase in molecular size. This is due to an increase in the size of the hydrophobic alkyl group.

New cards
18

Order of Boiling Point

carboxylic acids > alcohols > amines }- Hydrogen Bonding

> ketones > aldehydes}- Strong dipole dipole interactions

> ethers > haloalkanes }- Weak dipole dipole interactions

> hydrocarbons }- Van der waal’s forces

always write answers for B.P questions in terms of the one with higher B.P

New cards
19

Acidic Character of Alcohols and Phenols

  • Alcohol is less acidic than water due to the presence of an electron-donating alkyl group (+I effect), the electron density of oxygen increases which decreases the ability to donate a proton.

  • Phenols are more acidic than water because phenoxide ion is stabilized by resonance.

ROH < H₂O < C₆H₅OH

  • Among 1°, 2°, and 3° alcohols, 1° alcohol > 2° alcohol > 3° alcohol because 3° has more +I = more electron density.

  • Among substituted phenols or phenol derivatives, phenols with electron-withdrawing groups are more acidic than phenols with electron-donating groups.

    phenol (e.w.g) > phenol > phenol (e.d.g)

New cards
20

Order of Acidic Character

3° Alcohol < 2° Alcohol < 1° Alcohol < H₂O < phenol (e.d.g) < phenol < phenol (e.w.g)

New cards
21

Chemical Properties of Alcohols
a) Reactions involving cleavage of O–H bond

  1. Reaction with metals

  2. Reaction with Alkali

  3. Reaction with Grignard Reagent

  4. Esterification

New cards
22

1) Reaction with Metals

knowt flashcard image
New cards
23

2) Reaction with Alkali

R-OH + NaOH → No reaction

<p>R-OH + NaOH → No reaction</p><p></p>
New cards
24

3) Reaction with Grignard Reagent

R-OH + R’MgX → R-H +Mg(X)(OR)

New cards
25

4) Esterification (Preparation of Esters)

i) How do you convert Propan-1-ol to 1-propoxypropane? (i think it comes under this topic)

Model 1: Alcohol + Carboxylic Acid → [conc.H₂SO₄] Ester + Water

  • R-OH + R’COOH → [conc.H₂SO₄] R’-C(O)-OR +H₂O

  • CH₃CH₂-OH + CH₃COOH → [conc.H₂SO₄] CH₃-C(O)-O-CH₂CH₃ +H₂O

Model 2: Alcohol + Acid A

New cards
26

Acetylation of Salicylic Acid

knowt flashcard image
New cards
27

Reactions involving cleavage of carbon – oxygen (C–O) bond

  1. Lucas Test

  2. With Chlorinating Agents

  3. Dehydration

  4. Test for Phenol

  5. Haloform Reaction

  6. Catalytic Dehydrogenation

New cards
28

1) Lucas Test (Reaction with Hydrogen Halides)

i) Give a chemical test to distinguish between 2-Pentanol and 3-Pentanol

ii) Give a chemical test to distinguish between 1-Propanol and 2-Propanol.

  • Test is used to distinguish 1ᵒ, 2ᵒ and 3ᵒ alcohols

  • Depends on order of reactivity ( 3ᵒ>2ᵒ>1ᵒ )

Turbidity → Formation of precipitate

General Formula:

ROH + HX → R–X + H₂O

Reactions:
1ᵒ Alcohol:

R-CH₂-OH + HCl → [ZnCl₂] R-Cl + H₂O

No turbidity at room temperature

2ᵒ Alcohol:

R-CH(R)-OH + HCl → [ZnCl₂] R-CH(R)-Cl + H₂O

Turbidity after 5-10 minutes

3ᵒ Alcohol:

R-CH(R)(R)-OH + HCl → [ZnCl₂] R-CH(R)(R)-Cl + H₂O

Immediate Turbidity

New cards
29

2) With Chlorinating Agents

  1. ROH + PCl₅ → RCl + POCl₃ + HCl

  2. ROH + SOCl → RCl + SO + HCl

  3. 3ROH + PCl₃ → 3R-Cl + H₃PO₃

New cards
30

3) Dehydration

i) How do you convert Propan-2-ol to propane?

ii) How would you convert ethanol to ethene?

knowt flashcard image
New cards
31

Mechanism of Dehydration of Alcohol

use note

Step 1: Protonation

Step 2: Elimination of water

Step 3: Deprotonation

<p><em>use note</em></p><p>Step 1: Protonation</p><p>Step 2: Elimination of water</p><p>Step 3: Deprotonation</p>
New cards
32

4) Test for Phenol (neutral FeCl₃ Test)

i) Give a chemical test to distinguish between Benzoic acid and Phenol

ii) Give a chemical test to distinguish between Ethanol and Phenol

C₆H₅OH + FeCl₃ → (C₆H₅O)₃Fe violet precipitate + 3HCl

New cards
33

5) Haloform Reaction (Iodoform Test)

i) Give a chemical test to distinguish between 2-Pentanol and 3-Pentanol

ii) Give a chemical test to distinguish between 2-propanol and 2-methyl-2-propanol.

iii) Give a chemical test to distinguish between 1-Propanol and 2-Propanol.

The test only identifies alcohol with (CH₃-CH(OH)-)


CH₃-CH(OH)-R → [NaOI, NaOH + I₂] CHIyellow precipitate + R-COONa

New cards
34

6) Catalytic Dehydrogenation (Oxidation)

i) How do you convert Propan-2-ol to propanone?

ii) How do you convert Hexan-1-ol to hexanal?

R-CH₂OH → [Cu,573K] R-CHO

R-CH(R’)-OH → [Cu,573K] R-C(R’)=O

(CH₃)C(CH₃)(CH₃)(OH) → [Cu, 573K] CH₃-C(CH₃)=CH₃

New cards
35

Chemical Properties of Phenol

  1. Oxidation

  2. Reduction

  3. Bromination

  4. Nitration

  5. Reimer Tiemann Reaction

  6. Kolbe’s Reaction

  7. Acetylation of Salicylic Acid

New cards
36

1) Oxidation

i) How do you convert Phenol to Benzoquinone?

knowt flashcard image
New cards
37

2) Reduction (Reaction Of Phenol With Zinc Dust)

i) How do you convert Phenol to Benzene?

ii) How is toluene obtained from phenol?

iii) How would you obtain acetophenone from phenol?

C₆HOH → [Zn dust] C₆H₆

<p><span>C₆H</span>₅<span>OH → [Zn dust] C</span>₆H₆</p>
New cards
38

3) Bromination

i) How to convert Phenol to 2, 4, 6-tribromophenol?

knowt flashcard image
New cards
39

4) Nitration

i) How do you convert Phenol to 2,4,6-trinitrophenol(picric acid)?

ii) Which of the following isomers is more volatile: o-nitrophenol or p-nitrophenol?

  • It is named picric acid because of its bitter taste

  • Picric acid is used to make explosives

  • o-Nitrophenol is more steam volatile than p-Nitrophenol due to the presence of intramolecular

    H-bonding.

  • p-nitrophenol shows intermolecular H–bonding.

<ul><li><p>It is named picric acid because of its bitter taste</p></li><li><p>Picric acid is used to make explosives</p></li><li><p>o-Nitrophenol is more steam volatile than p-Nitrophenol due to the presence of intramolecular</p><p>H-bonding. </p></li><li><p>p-nitrophenol shows intermolecular H–bonding.</p><p></p></li></ul>
New cards
40

5) Reimer Tiemann Reaction

C₆H₅OH → [CHCl₃, NaOH, H₃O⁺] C₆HOH CHO

<p>C₆H₅OH → [CHCl<span>₃, NaOH, H₃O⁺] </span>C₆H<span>₄</span>OH CHO</p><p></p>
New cards
41

6) Kolbe’s Reaction

C₆H₅OH → [CO₂, NaOH, H₃O⁺] C₆H₄OH COOH

<p>C₆H₅OH → [CO₂, NaOH, H₃O⁺] C₆H₄OH COOH</p>
New cards
42

Commercially Important Alcohols

  1. Methanol

    • aka wood spirit bc it was produced by destructive distillation of wood

    • Can cause blindness and large quantities causes even death

  2. Ethanol

    • Glucose and fructose undergo fermentation in the presence of another enzyme, zymase, which is found in yeast to form ethantol

    • The commercial alcohol is made unfit for drinking by mixing in it some copper sulphate (to give it a colour) and pyridine (a foul smelling liquid).

  • 100% pure ethanol is called absolute alcohol

  • 95% ethanol is called rectified spirit/surgical spirit/rubbing alcohol

  • Methylated spirit - Mixture of methanol and ethanol

New cards
43

Ethers

R-O-R

OR - Alkoxy group

Simple ethers - Symmetric (R-O-R)

Mixed ethers - Asymmetric (R-O-R’)

New cards
44

Preparation of Ethers

  1. By Dehydration of Alcohols

  2. Williamson Synthesis

New cards
45

Preparation of Ethers
1) By Dehydration of Alcohols

  • Can only make simple/symmetric ethers, mixed ethers cannot be prepared

  • The reaction follows the SN₂ mechanism (substitution) and not the elimination

  • Branched alkyl ethers cannot be prepared since this reaction follows SN₂ mechanism and branched alkyl ethers show more steric hindrance

  • Aromatic ethers cannot be prepared as they are less reactive towards nucleophilic substitution due to partial double bond character by C-O bond resonance

<ul><li><p>Can only make simple/symmetric ethers, mixed ethers cannot be prepared </p></li><li><p>The reaction follows the SN<span>₂ mechanism (substitution) and not the elimination</span></p></li><li><p>Branched alkyl ethers cannot be prepared since this reaction follows SN₂ mechanism and branched alkyl ethers show more steric hindrance</p></li><li><p>Aromatic ethers cannot be prepared as they are less reactive towards nucleophilic substitution due to partial double bond character by C-O bond resonance</p></li></ul>
New cards
46

Preparation of Ethers
2) Williamson Synthesis

R-O-Na + R’-X → R-O-R’ + NaX

CH₃-CH₂-O-Na + CH₃-Cl → CH₃-CH₂-O-CH₃ + NaCl

  • Can make both simple and mixed ethers

  • Better results are obtained if the alkyl halide is primary. In case of secondary and tertiary alkyl halides, elimination competes over substitution.

New cards
47

Physical Properties of Ethers

  • The large difference in boiling points of alcohols and ethers is due to the presence of hydrogen bonding in alcohols.

  • The miscibility of ethers with water resembles those of alcohols of the same molecular mass.

New cards
48

Chemical Properties of Ethers

  1. Reaction with HX

  2. Electrophilic Substitution

New cards
49

Chemical Properties of Ethers

1) Reaction with HX

New cards
50

Phenol to Anisole

knowt flashcard image
New cards
51

Chemical Properties of Ethers

2) Electrophilic Substitution

i) How do you convert Anisole to p-bromoanisole?

knowt flashcard image
New cards

Explore top notes

note Note
studied byStudied by 12 people
Updated ... ago
5.0 Stars(1)
note Note
studied byStudied by 236 people
Updated ... ago
5.0 Stars(1)
note Note
studied byStudied by 11 people
Updated ... ago
5.0 Stars(1)
note Note
studied byStudied by 12 people
Updated ... ago
5.0 Stars(1)
note Note
studied byStudied by 20 people
Updated ... ago
5.0 Stars(1)
note Note
studied byStudied by 15 people
Updated ... ago
5.0 Stars(1)
note Note
studied byStudied by 8 people
Updated ... ago
5.0 Stars(1)
note Note
studied byStudied by 36 people
Updated ... ago
5.0 Stars(1)

Explore top flashcards

flashcards Flashcard57 terms
studied byStudied by 69 people
Updated ... ago
4.8 Stars(4)
flashcards Flashcard279 terms
studied byStudied by 2 people
Updated ... ago
5.0 Stars(1)
flashcards Flashcard40 terms
studied byStudied by 10 people
Updated ... ago
5.0 Stars(1)
flashcards Flashcard37 terms
studied byStudied by 173 people
Updated ... ago
5.0 Stars(1)
flashcards Flashcard40 terms
studied byStudied by 15 people
Updated ... ago
5.0 Stars(1)
flashcards Flashcard113 terms
studied byStudied by 6 people
Updated ... ago
5.0 Stars(1)
flashcards Flashcard61 terms
studied byStudied by 131 people
Updated ... ago
5.0 Stars(3)
flashcards Flashcard77 terms
studied byStudied by 19 people
Updated ... ago
4.0 Stars(1)