Ch. 14Alcohols, Phenols, and Ethers

Milbank High School

Chapter Objectives

1.What is the general structure for an alcohol? A phenol? An ether?  

2.What are functional groups? Why are they useful in the study of organic chemistry? 

3.What structural feature is used to classify alcohols as primary, secondary, or tertiary?  

4.How are alcohols named by the common and IUPAC systems?  

5.Why are the boiling points of alcohols higher than those of ethers and alkanes of similar molar masses?  

Objectives Con’t

6.Why are alcohols and ethers of four carbons or less soluble in water while comparable alkanes are not?  

7.How are alcohols prepared from alkenes? What is Markovnikov's rule?  

8.How do various alcohols affect the human body?    9.What are the major reactions of alcohols? 10.What product is formed by the oxidation of a

primary alcohol? A secondary alcohol? A tertiary alcohol?

Objectives Con’t

11.Describe the structure and uses of some common polyhydric alcohols.

12.Describe the structure and uses of some phenols.

13.How does the structural difference between alcohols and ethers affect their physical characteristics and reactivity?

14.How are simple ethers named? Describe the structure and uses of some ethers.

Sec. 14.1General Formulas and Functional Groups Two of the three families contain a hydroxyl group

(OH) Alcohols Phenols

Ethers Often made from alcohols and phenols

All are considered organic derivatives of water.

General Formulas

Bent molecule Central oxygen atom Hydrogen and alkyl group attached (R) or an aryl

group (Ar)

                              

General Formulas Con’t

Alcohols R-O-H

Phenols Ar-OH Benzene ring with an OH

Ethers R-O-R

Functional Groups

Group of atoms which confers characteristic properties on a family of organic compounds OH COOH Alkanes: none

Sec. 14.2 Classification and Nomenclature of Alcohols Properties of alcohols depend on the

arrangement of the carbon atoms of the molecule

Primary (1°) carbon atom

Secondary (2°) carbon atom

Tertiary (3°) carbon atom

                                                                                                         

                                                                  

Classification and Nomenclature of Alcohols Primary Alcohol

RCH2OH

Secondary Alcohol R2CHOH

Tertiary Alcohol R3COH

IUPAC Naming

Name the longest continous chain of carbons containing the –OH group

Number which carbon the –OH is attached to End name in –ol If more than one hydroxyl group, use suffixes

–diol, -triol, etc.

Physical Properties of Alcohols Replacement of hydrogen with a hydroxyl

group greatly changes properties Not as homologous as alkanes Higher boiling points

Due to strong intermolecular attractions Solubility

The more compact the molecule is, the more soluble it is

4-5 carbons or less—soluble in water

Sec. 14.4Preparation of Alcohols Hydration Reactions

                                                                                 

                                                                                                 

                                                                                             

Markovnikov’s Rule

The hydroxyl group goes on the carbon with fewer hydrogens

                                                                                                        

 

Production of alcohols

Methanol

1.7 billion gallons produced a year Used in formaldehyde, acetic acid, fuels

(MTBE), silicones, refrigerants

                                                                     

Production of Alcohols

Ethanol Produced from sugars or starches by fermentation

C6H10O5 C6H12O6 2CH3CH2OH + 2CO2

(Enzymes as catalysts)

It’s the alcohol that’s found in those certain beverages that people shouldn’t drink

Production of Alcohols Con’t

Wines 12% ethanol

Champagnes 14-20% ethanol

Beers 4% ethanol

Whiskey 50% ethanol

Proof spirit: alcoholic content of a beverage, twice that of the alcohol content by volume (whiskey: 100 proof)

Sec. 14.5Physiological Effects of Alcohols LD50 (Lethal dose to 50% of a population) Tested on animals Varies per species though See table 14.5

Methanol

Can cause permanent blindness or death in high amounts

Vapors are very dangerous as well

Ethanol

Toxic to humans Acute poisoning kills several hundred a year

(drinking contests) Long term poisioning

Most serious drug problem in US 40 times more addicts than heroin

Isopropyl Alcohol

Rubbing alcohol Rapid evaporation Antiseptic More toxic than ethanol, but induces

vomitting Used for the manufacture of acetone

Sec. 14.6Chemical Properties of Alcohols Reactions

Occur on the functional groups May involve hydrogen atoms as well

Dehydration Oxidation

Dehydration

Removal of water Sulfuric acid as a catalyst Produces:

Ether (excess ROH) + water Alkene (excess H2SO4) + water

                                                  

 

Oxidation

Result depends on if alcohol is primary, secondary, or tertiary

Primary Produces an aldehyde Then goes through further oxidation to produce a

carboxylic acid Secondary

Produces a ketone Tertiary

No reaction Can’t break the carbon-carbon bond

Oxidation Con’t

                                                                       

                                                                         

Sec. 14.7 Multifunctional Alcohols: Glycols and Glycerol More than one hydroxyl group Polyhydric groups Dihydric alcohols Trihydric alcohols

Glycols

Dihydric alcohols 1,2 ethanediol (ethylene glycol)

HOCH2CH2OH Two hydroxyl groups—extensive

intermolecular hydrogen bonding Higher boiling point Used as anti-freeze

                                             

                                             

Glycerol

Most important trihydric alcohol Syrupy liquid Nontoxic, product of the hydrolysis of fats and

oils Nitroglycerin

Detonates on slight impact Reaction produces temps of 3000 °C and

pressures above 2000 atm

Sec. 14.8Phenols Slightly acidic Neutralized by strong bases

      

                                                                                                                            

Phenols

Used as: Antiseptic Disinfectants

First used was pure phenol—proved to be too toxic Methyl derivatives

Cresols Creosote

                                           

                             

Phenols

Dihydroxybenzenes

Components of biochemical molecules

                                                                    

Sec. 14.9Ethers Derivatives of water Both hydrogen atoms are replaced

Naming Symmetrical Name groups attached and add ether

                                                 

Properties

Quite inert Although react violently in the air Low boiling points—no hydrogen bonds Diethyl ether

Forms a peroxide in air First general anesthetic