11

Functional Groups:

- Carboxylic Acids - Esters - Amides

- Aldehydes- Ketones- Amines

Mr. Shields Regents Chemistry U17 L02

22

Organic AcidsOrganic Acids

Condensed form is written –COOHCondensed form is written –COOH– A A carbonyl groupcarbonyl group and a and a hydroxyl grouphydroxyl group bonded to same C bonded to same C– Known as aKnown as a carboxyl groupcarboxyl group– An organic acidAn organic acid

The Carboxyl group is always a terminal functional The Carboxyl group is always a terminal functional groupgroup

33

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

A Weak Acid

44

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 no need to give it a number. It’s always on C #1C #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

55

Naming Organic AcidsNaming Organic Acids

Name this compound:

hexanoic acid

C-C-C-C-C-COOH

66

- Sharp or noxious smells

- polar molecule that can form 2 hydrogen bonds with themselves or 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

77

EstersEsters

Esters are derivatives of Carboxylic acidsEsters are derivatives of Carboxylic acids

– Combination of an Acid and an AlcoholCombination of an Acid and an Alcohol

– The The alcohol portionalcohol portion provides the “Alkyl” part of the ester provides the “Alkyl” part of the ester namename

88

Naming EstersNaming Esters

Esters are not a terminal group but the carbonyl carbon Esters are not a terminal group but the carbonyl carbon is considered to be C #1is considered to be C #1

Name the group attached to the hydroxyl oxygen first Name the group attached to the hydroxyl oxygen first (the alkyl group)(the alkyl group)

Next name the carboxylate Next name the carboxylate carbon chaincarbon chain, dropping the –, dropping the –e and adding –oatee and adding –oate

Written condensed format is RCOOR’Written condensed format is RCOOR’

99

PropertiesProperties

Esters have Esters have distinctive odorsdistinctive odors (flowers, flavors etc.) (flowers, flavors etc.)- It’s a f- It’s a function of which alcohol is combined withunction of which alcohol is combined with

which acidwhich acid

Alcohol Acid Ester Fragrance

EthanolEthanol Butanoic acidButanoic acid Ethyl butanoateEthyl butanoate Pineapple

PentanolPentanol Ethanoic acidEthanoic acid Pentyl ethanoatePentyl ethanoate Banana

OctanolOctanol Ethanoic acidEthanoic acid Octyl ethanoateOctyl ethanoate Orange

MethanolMethanol Salicylic acidSalicylic acid Methyl salicylateMethyl salicylate wintergreen

MethanolMethanol Butanoic acidButanoic acid Methyl butanoateMethyl butanoate apple

1010

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

butyl ethanoate

Ethyl butanoate

Name this compound:

Name this compound:

1111

AmideAmide

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

1212

Amide Physical PropertiesAmide Physical Properties

-Amides have very high BP’s due to strong H-bonding-Intermolecular hydrogen bonding possible

- H-bonding can occur between N, H and O

CH3 – C=O NH2

CHCH33COOCHCOOCH33 CHCH33COOHCOOH CH3CONHCH3CONH22

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

- BP’s are higher than similar esters and acids

1313

AmideAmide

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

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

Ethanamide

1414

AldehydesAldehydes

This group is always on a terminal C – so no need to This group is always on a terminal C – so no need to specify location by numberspecify location by number

Condensed 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 formula

Aldehydes have characteristic scents and tastesAldehydes have characteristic scents and tastes– Cinnamon, bannana, apple, raspberry flavors are Cinnamon, bannana, apple, raspberry flavors are

examplesexamples

1515

AldehydesAldehydes

To name aldehydes drop the –e To name aldehydes drop the –e from the end of the alkane and from the end of the alkane and add –al; C=O is C #1add –al; C=O is C #1

Name these two compounds:

Methanal(formaldehyde)

Butanal

1616

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

1717

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 o3-hexanone

2-pentanone

1818

AminesAmines

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

Nitrogen can form three covalent bonds (just like NHNitrogen can form three covalent bonds (just like NH33))– One must be to a carbon chainOne must be to a 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 C-C-N-H or C

C-C-N-C C

1919

Physical properties of AminesPhysical properties of Amines

Like ammonia, amines are polar compounds

And like ammonia, amines are Bronsted-Lowery Bases

- i.e they’re Proton acceptors H:N-R H

H+

2020

Physical properties of AminesPhysical properties of Amines

-Since amines can act as proton acceptors the reaction with a proton donor like HCl leads to an Ionic Compound

H:N-R H

HCl + H:N-R H

Cl- H +

2121

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

2222

Naming AminesNaming Amines

Need #’s to designate the location of the amineNeed #’s to designate the location of the amine

Name your carbon chain as an alkane, drop the –Name your carbon chain as an alkane, drop the –e and add –aminee and add –amine

2-butanamine

2323

Some nasty DIAMINES …Yuk!

2424

Amino AcidsAmino Acids

If you have an “-NHIf you have an “-NH22” and a COOH in one molecule it is an amino ” and a COOH in one molecule it is an amino acidacid

Related to both amines and acids are the Amino Acids

GLYCINE(Gly or G)

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

+ and COO-.

Smallest of the20 amino acidsCommonly Found in ProteinsAminoethonaoic acid

2525

Another Amino AcidAnother Amino Acid

Alanine (Ala; A)Alanine (Ala; A)

O O

HH33C-CH-C-OHC-CH-C-OH

NH2

2-aminopropanoic acid