Mari Do Now: – Take out HW – Any questions on the handout from yesterday? Agenda: – Alkenes and Alkynes – Ethers, Ketones, Esters HW: – #4-9,30,31,38-41.

Mari Mari

• Do Now:– Take out HW– Any questions on the handout from yesterday?

• Agenda:– Alkenes and Alkynes– Ethers, Ketones, Esters

• HW:– #4-9,30,31,38-41

IUPAC rules

1. Find the longest straight chain = parent chain

2. Number the parent chain in the direction that gives the lowest number to the substituents at the first point of difference.

3. Two or more identical groups are indicated by di, tri, tetra, etc.

CH3 CH2 CH2 CH2 CH

CH2 CH3

CH3Longest chain is 7 (not 6).This is 3-methylheptane.

.

2,3,6-trimethylheptane (not 2,5,6-trimethyl heptane)

2,2,6,6,7-pentamethyloctane (not 2,3,3,7,7-pentamethyloctane)

4. Different groups are listed in alphabetical order (di, tri, tetra, etc. don’t count; n, sec, tert don’t count; iso does).

5. If the numbering is the same in both directions, choose the numbering to follow the alphabetical order.

IUPAC rules

6-ethyl-5-isopropyl-2,2-dimethyloctane

5-ethyl-6-methyldecane

cyclic molecules

CC

C

H H

H

H

H

H

CH2

CH2

CH2

Cyclopropane

C

C C

C

H

H

H

H

H

H

H

H

CH2

CH2 CH2

CH2

Cyclobutane

C

C

C

C

C

H HH H

HH

HH

HH

CH2

CH2

CH2

CH2

CH2

Cyclopentane

C

CC

C

CC

H HH

H

H

H

HH

H

H

H

HCH2

CH2

CH2

CH2

CH2

CH2

Cyclohexane

Nomenclature for Cyclic Alkanes For compounds with a single ring, add the

prefix “cyclo-” to the root name for the alkane comprising the ring.

Nomenclature of the Substituted Cycloalkanes

If there is only one substituent, do not use the “1”.

If there is more than one substituent, you must use all numbers, including “1”

Number around the ring in a direction to get from the first substituent to the second substituent by the shorter path.

For equivalent degrees of substitution, number in a direction that follows the alphabetical sequence.

A carbon with greater substitution has precedence in numbering.

2. EthersIn an ether, an oxygen atom is bonded to two carbon atoms.

–C–O–C– .

has a common name that gives the alkyl names of the attached groups followed by ether.

Copyright © 2005 by Pearson Education, Inc.Publishing as Benjamin Cummings

7

Diethyl ether

anesthetic perfume solvent industrial solvent

Ether Practice R-O_R Draw the condensed structural formula of

methoxy propane:

4. KetonesIn a ketone, the carbon of the carbonyl group is attached to two other carbon atoms.

Copyright © 2005 by Pearson Education, Inc.Publishing as Benjamin Cummings

10

Acetone

Chapter 18 11

IUPAC Names for Ketones Replace -e with -one. Indicate the position

of the carbonyl with a number.

Number the chain so that carbonyl carbon has the lowest number.

For cyclic ketones the carbonyl carbon is assigned the number 1.

=>

Chapter 18 12

Examples

CH3 C

O

CH

CH3

CH3

O

Br

CH3 C

O

CH

CH3

CH2OH

3-methyl-2-butanone

3-bromocyclohexanone

4-hydroxy-3-methyl-2-butanone =>

Chapter 18 13

Boiling Points More polar, so higher boiling point than

comparable alkane or ether. Cannot H-bond to each other, so lower

boiling point than comparable alcohol.

=>

Chapter 18 14

Solubility Good solvent for alcohols. Lone pair of electrons on oxygen of

carbonyl can accept a hydrogen bond from O-H or N-H.

Acetone and acetaldehyde are miscible in water.

=>

Ketones Practice R-C-R Draw the condensed structural formula for

3-pentanone

14 | 16

Esters Ester – a compound that

has the following general formula RCOOR’

In the general formula for an ester the R and R’ can be any alkyl group.• Although R and R’ can be identical, they are

usually different.

Most esters have pleasant odors.• Many flowers and ripe fruits have fragrances

and tastes due to one or more esters.Section 14.4

NamingNamed after alcohol & carboxylic acid from which

they are derived.

Names of esters end in –oate.

CH3C

CH2 O

O

CH3

ethyl ethanoate

this part from the acid and is named after it

this part comes from the alcohol & is named after it

let’s name some esters!

Structural formulaeAlthough the previous structural formula are the

clearest way of showing esters, they can draw out in a shortened form.

ethyl ethanoate

CH3CCH2 O

O

CH3

Either…Or…

CH3C CH2O

O

CH3

In this version the acid part has been

written first

Identify the group attached to the C=O – this is from the acid

The group attached to the –O- is from the alcohol.

Esters Practice R-O-C-R

Draw the condensed structure for butyl hexanoate

Wait! What’s that smell?

Esters have strong, sweet smells.

Their bouquet is often floral or fruity.

This means they are used in food flavourings & perfumes.

Also, very good at dissolving organic compounds so often used as solvents.

ester fragranceethyl methanoate raspberries3-methylbutyl ethanoate pearsethyl 2-methylbutanoate applesphenylmethyl ethanoate jasmine