Introduction to Organic Chemistry and Biochemistry Instructor Dr. Upali Siriwardane (Ph.D. Ohio State) Office: 311 Carson Taylor Hall ; Phone: ; Office Hours: MTW 8: :00 am; ThF 9: :00 am 1:00 - 2:00 pm. December 19, 2014: Test 1 (Chapters 12-13) January 26, 2015: Test 2 (Chapters 14-16) February 13, 2015: Test 3 (Chapters 17-19) March 2, 2015: Test 4 (Chapters 20-22) March 3, 2015: Make Up Exam: Chapters 12-22) Bring Scantron Sheet 882-E Chemistry 121(001) Winter CHEM 121 Winter 15

Chapter 14 and GHW#4 Questions Introduction Alcohols, Phenols, and Ethers:

Chapter 14. Alcohols, Phenols, and Ethers 14.1 Bonding Characteristics of Oxygen Atoms in Organic Compounds, Structural Characteristics of Alcohols, Nomenclature for Alcohols, Isomerism for Alcohols, Important Commonly Encountered Alcohols, Physical Properties of Alcohols, Preparation of Alcohols, Classification of Alcohols, Chemical Reactions of Alcohols, Polymeric Alcohols, Structural Characteristics of Phenols, Nomenclature for Phenols, Physical and Chemical Properties of Phenols, Occurrence of and Uses for Phenols, Structural Characteristics of Ethers, Nomenclature for Ethers, Isomerism for Ethers, Physical and Chemical Properties of Ethers, Cyclic Ethers, Sulfur Analogs of Alcohols, Sulfur Analogs of Ethers, 457

Alcohols, Phenols, and Ethers Functional groups: alcohol: R-O-H phenols: Ar-OH ether: R-O-R' thiol: R-S-H Phenyl, Ar = C 6 H 5 Alkyl, R = CH 3 Mehtyl etc.

1. Bonding Characteristics of Oxygen Atoms in Organic Compounds

Structural Characteristics of Alcohols

Alcohols - Nomenclature IUPAC names IUPAC names – the parent chain is the longest chain that contains the -OH group – number the parent chain in the direction that gives the -OH group the lower number -eol – change the suffix -e to -ol Common names Common names alcohol – name the alkyl group bonded to oxygen followed by the word alcohol

Nomenclature of compounds containing functional groups The IUPAC system deals with functional groups two different ways. Modification of the hydrocarbon name to indicate the presence of a functional group. alcohol, -OHuse -ol ending. ether: CH 3 CH 2 -O-CH 3 use methoxy methoxy ethane thiol thiol: R-S-H use -thiol ending.

Alcohols - Nomenclature Problem: Write the IUPAC name of each alcohol

Alcohols - Nomenclature Compounds containing diols – two -OH groups are named as diols, triols – three -OH groups are named as triols, etc.

Alcohols - Nomenclature Examples:

1. Identify the Alcohols, Phenols, and Ethers from the following and give their common and/or IUPAC names.

2. Circle the constitutional isomers of 1- hexanol among following alcohols.

Classification of alcohols Primary Secondary Tertiary.

3. Classify each of the following as 1', 2', or 3' alcohols. a) b) c) d)

Physical Properties of Alcohols Alcohols are polar compounds – both the C-O and O-H bonds are polar covalent

Hydrogen Bonding Alcohols associate in the liquid state by hydrogen bonding Hydrogen bonding Hydrogen bonding: the attractive force between a partial positive charge on hydrogen and a partial negative charge on a nearby oxygen, nitrogen, or fluorine atom – the strength of hydrogen bonding in alcohols is approximately 2 to 5 kcal/mol – hydrogen bonds are considerably weaker than covalent bonds (for example, 110 kcal/mol for an O-H bond) – nonetheless, hydrogen bonding can have a significant effect on physical properties

Hydrogen Bonding – Figure shows the association of ethanol molecules in the liquid state (only two of the three possible hydrogen bonds to the upper oxygen are shown here).

Boiling Points – alcohols have higher boiling points and are more soluble in water than hydrocarbons

Chemical Reactions of Alcohols 1) Combustion: Alcohol are very flammable and the combustion products are carbon dioxide and water. 2) Substitution Reactions: OH group is replaced by a another group such as halogen. 3) Elimination Reactions : Intarmolecular dehydration : Water is removed from a alcohol molecule and a alkene is produced. ( H 2 SO 4 at 180  ) Intermolecular dehydration : Water is removed from two alcohol molecules and an ether is produced. ( H 2 SO 4 at 140  ) Williamson Ether synthesis. 4) Oxidation Reactions : Oxygen is added to 1ry and 2ry alcohols

Dehydration of Alcohols  -elimination An alcohol can be converted to an alkene by elimination of H and OH from adjacent carbons (a  -elimination) – 1° alcohols must be heated at high temperature in the presence of an acid catalyst, such as H 2 SO 4 or H 3 PO 4 – 2° alcohols undergo dehydration at somewhat lower temperatures – 3° alcohols often require temperatures only at or slightly above room temperature

Zaitsev’s rule (or the opposite of Markovnikov’s rule) Dehydration of an alcohol can result in more than one alkene product, because hydrogen loss can occur from either of the neighboring carbon atoms. Hydrogen is removed from the carbon with lowest hydrogen atoms ( poor get poorer)

Dehydration of Alcohols – examples:

4a. Complete the following reactions of alcohol. a) Dehydration:

4b) What is Zaitsev Rule?

5) Complete the following reactions of alcohol oxidation:

6) Draw condensed formula of each of the following: a.3-Hexanol b.1,2,3-Pentanetriol c.2-Methyl-2-pentanol d. Cyclohexanol e. 3,4-dimethyl-3-heptanol

7) Draw the alkene products of the dehydration of the following alcohols: a)2-Pentanol: b)3-Methyl-1-pentanol: c)2-Butanol: d)4-Chloro-2-pentanol: e)1-Propanol:

Oxidation of Alcohols Oxidation of a 1° alcohol gives an aldehyde or a carboxylic acid, depending on the oxidizing agent and experimental conditions – the most common oxidizing agent is chromic acid – chromic acid oxidation of 1-octanol gives octanoic acid

Oxidation of Alcohols – to oxidize a 1° alcohol to an aldehyde, use PCC – PCC oxidation of geraniol gives geranial Tertiary alcohols are not oxidized by either of these reagents; they are resistant to oxidation

8) Give the oxidation products of the following alcohols. If no reaction occurs, write N.R.