Functional Groups:

- Aldehydes- Ketones- Organic Acids- Esters- Amines- Amides

AldehydesAldehydes

Group is always on a terminal C – no need to specify Group is always on a terminal C – no need to specify location by numberlocation by numberCondensed it is symbolized by a -CHO group at the Condensed it is symbolized by a -CHO group at the end of the formulaend of the formulaC = O is known as a carbonyl groupC = O is known as a carbonyl group– Drives the physical and chemical properties of these Drives the physical and chemical properties of these

compoundscompounds

Aldehydes have characteristic scents and tastesAldehydes have characteristic scents and tastes– Cinnamon is an exampleCinnamon is an example

AldehydesAldehydes

Drop the –e from the end of the Drop the –e from the end of the alkane and add –al; C=O is C #1alkane and add –al; C=O is C #1

Name these two compounds:

Methanal(formaldehyde)

Butanal

KetonesKetones

Like the aldehydes the Functional group is the Like the aldehydes the Functional group is the carbonyl group C=Ocarbonyl group C=O

Contains an alkyl group on either side of the C=OContains an alkyl group on either side of the C=O– In aldehydes one side is an alkyl group the other is HIn aldehydes one side is an alkyl group the other is H

Often used as a solventOften used as a solvent– Acetone is one exampleAcetone is one example

Naming KetonesNaming Ketones

Number the C chain so C=O has the lowest #Number the C chain so C=O has the lowest #

Drop the final e from the alkane name and add -oneDrop the final e from the alkane name and add -one

Name these compounds:

C-C-C-C-C

C

o3-hexanone

4-methyl-2-pentanone

PropertiesPropertiesBoth aldehydes & ketones haveA carbonyl functional group.

C=O is polar & their compounds Are polar. This leads to:

-Higher B.P’s than non-polar molecules

-Lower than alcohols that can H-bond w/ each other

-Can not H-bond between each other but can H-bond to solvents like water - Lower MW compounds are appreciably soluble in water

Propanone Propanal

PropertiesProperties

ButaneButane DiethylDiethyl

etherether

PropanalPropanal PropanonePropanone 1-propanol1-propanol

M.W.M.W. 5858 5858 5858 5858 6060

B.P (deg.C)B.P (deg.C) 00 3535 4949 5656 9797

SolubilitySolubility

g/100g Hg/100g H22OO

Insol.Insol. 88 1616 FullyFully

misciblemiscible

Fully Fully misciblemiscible

Organic AcidsOrganic Acids

Condensed form is written –COOHCondensed form is written –COOH– A carbonyl group and a hydroxyl group bonded to CA carbonyl group and a hydroxyl group bonded to C– Known as a Known as a carboxyl groupcarboxyl group

A terminal functional groupA terminal functional groupThe carboxyl group is an organic acid. The carboxyl group is an organic acid. – It is the H on the end of COOH that is donated as a It is the H on the end of COOH that is donated as a

proton (Hproton (H++))– What is left is the anion What is left is the anion R-COOR-COO--

Carboxylic acids ionize in water to form a proton andA carboxylate anion

Naming Organic AcidsNaming Organic Acids

The carboxyl group is a The carboxyl group is a terminalterminal group group– no need to give it a number. It’s always on C #1no need to give it a number. It’s always on C #1

Drop the –e from the alkane name and add Drop the –e from the alkane name and add –oic–oic acidacid

Name this compound:

Butanoic acid

Naming Organic AcidsNaming Organic Acids

Name this compound:

Butanoic acid

Name this compound: 2,4-dimethylhexanoic acid

C-C-C-C-C-COOH C C

Some Common Carboxylic acidsSome Common Carboxylic acids

HC=O OH

Methanoic acid“formic acid”

CH3C=O OH

Ethanoic Acid“Acetic Acid”

The sting of ants Vinegar

C-C-C-COOH

Butanoic acid

Rancid butter smell

- Sharp or noxious smells

- polar and can form 2 hydrogen bonds with themselves and with water

Physical propertiesPhysical properties

C-C=O OH

HOO=C- C

C-C=O OH

HO H

This leads to high B.P. and high solubility in water- 1st four acids are totally miscible in water

Comparison of propertiesComparison of properties

Butane Diethyl

ether

Propanal Propanone 1-propanol ethanoic

M.W.M.W. 5858 5858 5858 5858 6060 6060

B.P B.P (deg.C)(deg.C)

00 3535 4949 5656 9797 118118

SolubilitySolubility

g/100g g/100g HH22OO

Insol.Insol. 88 1616 FullyFully

misciblemiscible

Fully Fully misciblemiscible

FullyFully

misciblemiscible

EstersEsters

Esters are derivatives of Carboxylic acidsEsters are derivatives of Carboxylic acids– Combination of an Alcohol and an AcidCombination of an Alcohol and an Acid– The The alcohol alcohol provides the alkyl portion of the ester nameprovides the alkyl portion of the ester name– Esters are polar but can not form hydrogen bonds with Esters are polar but can not form hydrogen bonds with

one anotherone another– BP’s of esters are lower than alcohols or acids with BP’s of esters are lower than alcohols or acids with

similar masssimilar mass

Physical propertiesPhysical properties

Butanal Butanone Methyl ethanoate

1-butanol Propanoic

Acid

M.W.M.W. 7272 7272 7474 7474 7474

B.P (deg.C)B.P (deg.C) 7676 8080 57.557.5 118118 141141

PropertiesProperties

Esters have Esters have distinctive odorsdistinctive odors (flowers, flavors etc.) (flowers, flavors etc.)- - Function of which alcohol is combined with which acidFunction of which alcohol is combined with which acid

AlcoholAlcohol AcidAcid EsterEster FragranceFragrance

EthanolEthanol Butanoic acidButanoic acid Ethyl butanoateEthyl butanoate PineapplePineapple

PentanolPentanol Ethanoic acidEthanoic acid Pentyl ethanoatePentyl ethanoate BananaBanana

OctanolOctanol Ethanoic acidEthanoic acid Octyl ethanoateOctyl ethanoate OrangeOrange

MethanolMethanol Salicylic acidSalicylic acid Methyl salicylateMethyl salicylate wintergreenwintergreen

MethanolMethanol Butanoic acidButanoic acid Methyl butanoateMethyl butanoate appleapple

Naming EstersNaming Esters

Esters are not a terminal group but they are Esters are not a terminal group but they are unique because of the carboxyl group therefore unique because of the carboxyl group therefore the carbonyl carbon is considered to be C #1the carbonyl carbon is considered to be C #1Name the group attached to the hydroxyl oxygen Name the group attached to the hydroxyl oxygen first (the alkyl group)first (the alkyl group)Next name the carboxylate carbon chain, Next name the carboxylate carbon chain, dropping the –e and adding –oatedropping the –e and adding –oateWritten condensed format is RCOOR’Written condensed format is RCOOR’

O CH3-C-O-CH2-CH2-CH-CH3 CH3

3-methylbutyl ethanoate

Ethyl butanoate

Name this compound:

Name this compound:

2-methylbutyl ethanoate

(Not IUPAC)

What alcohols and acids produce the above esters?

(Not IUPAC)

AmideAmide

Like esters the amide functional group is a Like esters the amide functional group is a derivative of carboxylic acidsderivative of carboxylic acids– OH replaced by the amine groupOH replaced by the amine group

The amide group is a terminal groupThe amide group is a terminal group

Important biological moleculesImportant biological molecules– Links amino acids together to form proteinsLinks amino acids together to form proteins

Amide Physical PropertiesAmide Physical Properties

-Amides have very high BP’s due to strong intermolecular hydrogen bonding

- higher than similar esters and acids- H-bonding can occur between N, H and O

CH3 – C=O NH2

CHCH33COOCHCOOCH33 CHCH33COOHCOOH CH3COONHCH3COONH22

B.P. (deg. C)B.P. (deg. C) 57.557.5 118118 221221

AmideAmide

Take the name of the alkane with the same number of Take the name of the alkane with the same number of carbon atomscarbon atoms

Drop the –e from the alkane name and add –amideDrop the –e from the alkane name and add –amide

Amide carbon is carbon #1 when naming side chainesAmide carbon is carbon #1 when naming side chaines

Ethanamide

Name this compound:

C-C-C=O C NH2

2-methylpropanamide

AminesAmines

Nitrogen is the functional part of an amineNitrogen is the functional part of an amine

Nitrogen can form three bonds (just like NHNitrogen can form three bonds (just like NH33))– One must be to the carbon chainOne must be to the carbon chain

– The other two bonds can be to Carbon and/or HThe other two bonds can be to Carbon and/or H22

C-C-NH2 or

PrimaryAmine

C-C-N-H or CSecondaryAmine

C-C-N-C CTertiaryAmine

Physical properties of AminesPhysical properties of Amines

Like ammonia, amines are polar compounds

H:N-H H

H can also be CarbonBased groups

And like ammonia, amines are Bronsted-LoweryBases

- both are Proton acceptors

H+

Physical properties of AminesPhysical properties of Amines

H:N-H H

- Since amines can act as proton acceptors reaction With a proton donor like HCl will lead to a salt, i.e. an ionic compound

HCl + H:N-H H

Cl- H +

Physical Properties of AminesPhysical Properties of Amines

Amines can hydrogen bond like alcohols or Carboxylic acids

- Contains N and H- H-bonding raises the B.P. but it is not

as high as the alcohols or acids

HC-C-N H

HN-C-CH

Ethanoic Ethanoic acidacid

EthanolEthanol Ethyl Ethyl amineamine

B.P. (deg B.P. (deg C)C)

118118 7878 1717

Tertiary amines have higher BP’s than secondary and secondary is higher than primary

Physical properties of AminesPhysical properties of Amines-Amines can H-bond with water

-Leads to high water solubility up to about 6C

Methyl

Amine

Ethyl

Amine

Propyl

Amine

Butyl

Amine

Sol

(g/100g H20)

v. Sol Totally

miscible

Totally

Miscible

v. sol

-Amines have very strong odors- Methyl and ethyl amine smells like ammonia-Higher MW amines often have a fishy smell

-Aromatic amines are generally toxic-Readily absorbed through skin often with fatal results

AminesAmines

Need #’s to designate the location of the amineNeed #’s to designate the location of the amineName your carbon chain as an alkane, drop the –Name your carbon chain as an alkane, drop the –e and add –aminee and add –amineIf there are 2 amines indicate their location and If there are 2 amines indicate their location and add –diamine to the alkane nameadd –diamine to the alkane name

2-butanamine

Name this compound:

C-C-C-C-C-CN N

1,3-hexadiamine

Amino AcidsAmino Acids

If you have a “N” and a COOH it is an amino acidIf you have a “N” and a COOH it is an amino acid

Related to amines are the Amino Acids

GLYCINE

Since the amino group is a proton acceptor and theCarboxylic acid is a proton donor amino acids areActually NH3

+ and COO-.