Alcohols and Phenols 1435-1436 2014-2015 1

know the difference in structure between alcohols and phenols Learning Objectives Chapter six concerns alcohols and phenols and by the end of this chapter the student will: know the difference in structure between alcohols and phenols Know the different classes of alcohols Know how to name alcohols and phenols Know the physical properties (solubility, boiling and melting points) Know how hydrogen bonds are formed and its effect on boiling points of alcohols Know the acidic properties of alcohols and phenols know the different methods that can be used to prepare alcohols and phenols. Know the chemical reactions of these compounds ( some reactions are review, others are extensions of the chemistry that will be discussed on chapters 8, 9 & 10 145 Chem.

H-O-H R-O-H or PhCH2OH Ph-O-H Alcohols and Phenols Structure Of Alcohols and Phenols Alcohols and phenols may be viewed as organic derivatives of water. H-O-H R-O-H or PhCH2OH Ph-O-H Water Alcohol Phenol Alcohols and phenols have a common functional group, the hydroxyl group, —OH. - In alcohols the hydroxyl group is attached to an alkyl group, —R. - In phenols the hydroxyl function is directly attached to benzene ring 145 Chem. 3

Classification and Nomenclature of Alcohols Alcohols and Phenols Classification and Nomenclature of Alcohols Alcohols are classified according to the type of the carbon atom connected to the hydroxyl group (carbinol carbon) into: 145 Chem. 4

NOMENCLATURE OF ALCOHOLS Alcohols and Phenols NOMENCLATURE OF ALCOHOLS IUPAC Nomenclature Of Alcohols Alcohols are named according to the following rules: Select the longest continuous carbon chain that contains the -OH group. Replace the ending e of the alkane by the suffix –ol 2. If a molecule contains both an -OH group and a C=C or cΞc bond; Choose the chain that include both of them even if this is not the longest chain. The name should include suffixes indicate presence of both the OH group and the unsaturated groups. The OH group takes precedence over the double or triple bonds in getting the lower number. Cyclic alcohols are named using the prefix cyclo-, the carbon bearing the hydroxyl group is assumed to take number 1. 3. The suffix diol is added to the name of the parent hydrocarbon when there are two OH groups. 4. The suffix triol is added when there are three OH groups. 145 Chem. 5

Common Nomenclature Of Alcohols Alcohols and Phenols Common Nomenclature Of Alcohols List the names of alkyl substituents attached to the hydroxyl group, followed by the word alcohol. If two OH groups present on two adjacent carbons these known as glycols Primary alcohols CH3OH CH3CH2OH CH2=CHCH2OH Common Methyl alcohol Ethyl alcohol Allyl alcohol IUPAC Methanol Ethanol 2-Propen-1-ol 145 Chem. 6

Secondary and tertiary alcohols Alcohols and Phenols Secondary and tertiary alcohols Common Isopropyl alcohol Cyclopentyl alcohol Methylcyclohexyl alcohol IUPAC 2-Propanol Cyclopentanol 1-Methyl-1-cyclohexanol 145 Chem. 7

Examples Alcohols and Phenols 1-Phenylmethanol 2-Phenylethanol Benzyl alcohol (common name) 2-Phenylethanol 4-Methyl-2-cyclohexen-1-ol Ethan-1,2-diol Ethelene glycol (common name) 145 Chem. 8

Alcohols and Phenols Examples 145 Chem.

Physical Properties of Alcohols Alcohols and Phenols Physical Properties of Alcohols 1) Boiling Points of Alcohols The boiling points increase with increase in molecular weights. Alcohols have higher boiling points(b .p.) than alkanes of similar weight this is due to the presence of hydrogen bonds between molecules of alcohols. hydrogen bond 145 Chem. 10

Homework 2) Solubility Of Alcohols and Phenols Alcohol and water contain hydroxyl group that can form hydrogen bonds. The hydroxyl group is hydrophilic “water loving” The alkyl group of alcohols is hydrophobic “ water hating” As the number of the –OH group in alcohol increases, the solubility in water increases. Diols and triols are more soluble in water than monohydroxyalcohols. The lower alcohols are completely miscible with water As the number of carbons in the alcohol increases, the solubility in water decreases. Homework 145 Chem. 11

3) Acidic Properties of Alcohols: Alcohols are very weak acids Alcohols and Phenols 3) Acidic Properties of Alcohols: Alcohols are very weak acids The hydroxyl proton of an alcohol is weakly acidic A strong base can abstract the hydroxyl proton to give an alkoxide ion. Electron-withdrawing group (-I) increase acidity Electron-releasing group (+I) decrease acidity 145 Chem.

Synthesis (Preparation) of Alcohols 1- Hydration From Alkenes Alcohols and Phenols Synthesis (Preparation) of Alcohols 1- Hydration From Alkenes 1- Oxidation of Alkenes 2- From alkyl halide (elimination of HX using base gives alkene) nucleophilic substitution or aq. KOH 145 Chem. 13

3- Reduction of aldehydes, ketones and carboxylic acids Alcohols and Phenols 3- Reduction of aldehydes, ketones and carboxylic acids 145 Chem. 14

4- Addition of Grignard compounds to aldehydes & ketones Alcohols and Phenols 4- Addition of Grignard compounds to aldehydes & ketones Tertiary alcohol Ketone Secondary alcohol Primary alcohol Methanal formaldehyde 145 Chem. 15

1. Dissociation of O-H Bond Alcohols and Phenols Reaction of Alcohols 1. Dissociation of O-H Bond Reaction as acids (Breaking of oxygen- Hydrogen bond CO ـــــH) A. Formation of Salt (Alkoxide formation) Sodium ethoxide B. Formation of Esters H+ H+/ H2O 145 Chem. 16

2. Dissociation of C-O Bond Reaction with CــــOH bond cleavage Alcohols and Phenols 2. Dissociation of C-O Bond Reaction with CــــOH bond cleavage A. Elimination Reactions B. Substitution Reaction 145 Chem. 17

Alcohols and Phenols C. Oxidation Reactions 145 Chem 18

Nomenclature and acidity of Phenols Alcohols and Phenols Nomenclature and acidity of Phenols Phenols (compounds having hydroxyl group directly attached to a benzene ring ) are generally named as derivatives of the simplest member of the family, phenol Acidity : Alcohols and phenols have weak acidic properties. Phenols are much stronger acids than alcohols. Introduction of electron-withdrawing groups, such as NO2 or CN, on the ring increases the acidity of phenols. 145 Chem. 19

Alcohols and Phenols 145 Chem. 20

Alcohols and Phenols Synthesis of Phenols 145 Chem. 21

Alcohols and Phenols Reactions Phenols Ethers formation 145 Chem. 22

2. Electrophilic Substitution Reactions Alcohols and Phenols 2. Electrophilic Substitution Reactions 145 Chem. 23

Alcohols and Phenols Home Work 145 Chem. 24

4) The IUPAC name of is: A) 4-Ethyl-5-heptyn-3-ol Alcohols and Phenols 4) The IUPAC name of is: A) 4-Ethyl-5-heptyn-3-ol B) 4-Ethyl-5-heptan-3-ol C) 4-Ethyl-5-hepten-3-ol D) 4-Etyl-2-hepten-5-ol 5) The IUPAC name of is: A) 3-Methyl-1-bromocyclohexanol B) 2-Bromo-3-methylcyclohexanol C) 4-Bromo-2-methylcyclohexanol D) 3-Bromo-1-methylcyclohxanol 6) The most acidic compound is: 145 Chem. 25

7) The common name of 2-methyl-2-propanol is: A) Allyl alcohol Alcohols and Phenols 7) The common name of 2-methyl-2-propanol is: A) Allyl alcohol B) Isopropyl alcohol C) tert-Butyl alcohol D) Benzyl alcohol 8) The following reaction gives A) 4-Ethylphenol B) 2-Ethylphenol C) Ethylphenyl ether D) Ethylphenyl ketone 145 Chem. 26

Alcohols and Phenols 9) The major product for the following reaction is 10) The product of the reaction shown below is 11) Which of the following compounds has the highest boiling point?

Thank You for your kind attention ! Alcohols and Phenols Thank You for your kind attention ! Questions? Comments