Hydrocarbon Derivatives

AldehydesKetones

Carboxylic AcidsEsters

Carbonyl Group

• >CO

• oxygen attached to carbon by double covalent bond

• strong dipole-dipole forces

AlAldehydes

• general formula: RCH or RCHO

• carbonyl group alwaysalways at end of aldehyde

• find name of alkane with same # of C’s– change the -e (in ane ending) to -alal

• never need #’s for aldehydes – functional group always on end C

O

HCH H

=

OOH

HCH + H2

aldehydes created by

dehydrogenating an alcohol

HCH

Omethanal

H HCCH H

O

ethanalcommon name = acetaldehyde

common name = formaldehyde

Acetaldehyde

• carcinogenic compound

• natural component of many ripe fruits

• contributes to odors such as:

– rosemary, daffodil, bitter orange, camphor, angelica,

fennel, mustard, & peppermint

• component of cigarette smoke

CH3CH2CH2CHO

CHO ending indicates aldehyde

4 carbons so base name is butane

drop -e and add al butanal

Properties of Aldehydes

C=OR

H

C=OR

H

++

-- -

++

aldehydes are polar! ↑ bp over alkane with same C’s

H-bonding with H2O which ↑ solubility in water

H HO

+

-

Ketones

• carbonyl group: >C=O– located onon C in middle of chain instead of at end

• general format:

R and R‘: represent hydrocarbon chain - may or may not be the same

RCR'

=

O

Naming Ketoneones

• nearly always have number

• take corresponding alkane name:

– drop -e (from ane ending) & add -one

• # gives location of functional group: >C=O

– (lowest possible #)

H O HHCCCH H H

= propanonecommon name = acetone

CH3CH2CH2CCH3

=

O

2-pentanone

Aldehydes & Ketones

• known for appealing tastes & smells

– used as flavorings in food & candy– used as fragrances in perfumes– vanilla & cinnamon are aldehydes

Properties of Aldehydes & Ketones

• aldehydes & ketones: – contain C=O group – molecules polar (soluble in water)

• boiling point: – higher than alkanes (same # C’s) – lower than alcohols (same # C’s)

Carboxylic Acids

• general formula: RCOHH

• contains: carbonyl group AND hydroxyl group bonded to same C

• H is acidic; so ionizes in water! – carboxylic acids are electrolytes!carboxylic acids are electrolytes!

=

O Acidic H+

Ionization of Acetic Acid

CH3COOH(l) + H2O(l)

CH3COO-1(aq)+ H3O+1(aq)

Carboxylic Acids

• general format: R-C-OH

or

R-COOH

O

=

Which of the following is an electrolyte?

A. CH3OH

B. CH3COOH

C. CH2O

D. C3H6O

correct answer is B (carboxylic acid)

alcohol

aldehyde

ketone

Which of the following is a non-electrolyte?

A. HCl

B. CH3COOH

C. NaOH

D. CH3OH

Correct answer is D (alcohol)

Naming Carboxylic Acids

• nevernever needs number:– functional group always at end

• find name corresponding hydrocarbon– drop -e (from ane ending) & add -oic + acid

HCOH=

O

1 C methane methanoic acid sting from red ants, bees

HHCCOH H

=

O

ethanoic acid acetic acid

2 C ethane

CH3CH2CH2CH2COOH

5 C’s pentane

so the name is pentanoic acid

Common carboxylic acids• acetic acid – vinegar

– produced in doughs leavened with specific yeast (ex: sourdough bread)

• citric acid• tannic acid• ascorbic acid• lactic acid

– produced in overworked muscles & causes pain– poly(lactic acid) – biodegradable polymers used as

sutures in internal surgery

Properties of Carboxylic Acids

• contain -COOH group

• H bonded to O therefore hydrogen bonding – bp ↑ over corresponding alkane

• form H bonds with water so smaller acids are very soluble in water

Esters

• general format: RCOR‘

• R and R‘ = hydrocarbon branches

– can be same or different• esters contain carbonyl group and an O bridge

– both in middle of chain• esters are POLAR

• no H-bonding

=

O

Esters

• RCOR‘ or RCOOR’

combination of carboxylic acidcarboxylic acid & alcohol:alcohol:

• carbonyl group & “R” come from carboxylic acid

• bridging O & R’ come from alcohol

=O

Esters

• responsible for many distinctive odors

• pineapple

• banana

• orange

• apple

• wintergreen

Naming Esters

• name hydrocarbon branch bonded to O bridge first – branches end in –yl

• base name derived from branch containing carbonyl group – count up all C’s in this branch including the C in

the carbonyl

• find the hydrocarbon base name – drop the -e (from ane ending) & add -oate

CH3CH2C─O─CH3

=

O

carbonyl group

bridge O

name this branch 1st

methyl propanoate

CH3CH2CH2COCH2CH3

=

O

name this branch 1st

ethyl butanoate

bridge O

pineapple

CH3COCH2CH2CH2CH2CH3=

O bridge O

name this branch 1st

pentyl ethanoate

banana

CH3OCCH2CH2CH3

=

O

bridge O

name this branch 1st

4 C’s on the other side: but

methyl butanoate

apple

CH3CH2CH2CH2CH2CH2CH2CH2-O-C-CH3

O=bridge O

name this branch 1st

2 C’s on the other side: eth

octyl ethanoate

orange