CHEMISTRY 122

Alcohols and Ethers

Alcohols

An alcohol is an organic compound that contains the functional group – OH (hydroxyl)

They can be organized into groups depending on the number of R groups attached to the carbon with the hydroxyl group If only 1 R group is attached, it is a primary alcohol 2 R groups = secondary alcohol 3 R groups = tertiary alcohol

Naming Alcohols

Both IUPAC and common names exist When using the IUPAC naming system, both

straight-chain as well as substituted alcohols require dropping the ending of “e” and adding the suffix

“-ol”When identifying the numbering of carbon

from the continuous chain, give the lowest number to the carbon attached to the hydroxyl group

Alcohols containing more than one hydroxyl group are named diols, triols, and tetrols…

Common Names of Alcohols

Similar to the naming system of halocarbonsThe alkyl group associated with the parent

chain is identified, following by the word ‘alcohol’

Compounds with more than one hydroxyl group are called glycols

Phenols are those alcohol compounds that contain an aromatic ring

It is the parent compound Cresol is the common name for o, m, and p positions

within a ring

Properties of Alcohols

Capable of intermolecular hydrogen bonding They are derivatives of water (hydroxyl comes from

water), they are somewhat solubleAlcohols that contain up to four carbons are

completely soluble (because they form hydrogen bonds with water); those containing more than four have much lower solubilities

The carbon chain is not polar so not attracted to water; the hydroxyl group is polar and so, attracted to water

Uses of Alcohol

Antiseptic

Used as a base for cosmetics

Present in anti-freezes

Ethyl alcohol is an important industrial chemical Derived from the fermentation of sugar through the

action of yeast or bacteria Ethanol used in labs has been denatured by adding

methyl alcohol

Addition Reactions

The double bonds that exist between carbon can be easier to break than single covalent bonds

As a result, it is possible for a reaction to occur from an alkene or even alkyne

This advantage allows other functional groups to attach to carbon-based compounds

The addition of water to an alkene is called a hydration reaction A strong acid, usually HCl, is used as a catalyst

Other types of reactions…

When a halogen reacts with an alkene, the product is a disubstituted halocarbon

Hydrogen halides can also react with alkenes – which produces a monosubstituted halocarbon

The addition of hydrogen to an alkene to produce an alkane (or halocarbon) is called a hydrogenation reaction

Ethers

An oxygen bonded to two carbon groups is called an ether

Its general structure is R – O – RThe alkyl groups attached are named

alphabetically followed by the word etherWhen both R groups are the same, the ether

is said to be symmetricThe prefix di- is often used but can be

dropped

Properties of Ethers

Low boiling points compared to alcohols but higher than the boiling points of hydrocarbons and halocarbons.

More soluble in water than hydrocarbons and halocarbons but less than alcohols

Section Review 23.2, questions 7 – 12, p. 736