copyright © houghton mifflin company. all rights reserved.3–13–1 13 hydrocarbon derivatives ii...

Copyright © Houghton Mifflin Company. All rights reserved. 3–1

13 Hydrocarbon Derivatives II

Compounds with carbon-oxygen double bonds

Aldehydes

KetonesCarboxylic Acids

Esters

Amides



The carbon-oxygen double bond is called a carbonyl group, and occurs in different functional groups.

R1C

O

R2



The carbon of the carbonyl group has trigonal planar electronic and molecular geometry.

The carbonyl group is polar.

R1C

O

R2


13.2 Naming AldehydesAldehydes have at least one hydrogen

substituent on the carbonyl group. The other substituent can be any hydrocarbon.

HC

H

O

H3CC

H

O

CO

HN

H3C

H3C


13.2 Naming Aldehydes

Suffix is “-al”

1. Find longest chain that bears carbonyl

2. Number carbon chain so carbonyl is #1

3. Locate and name any other substituents

4. Final “e” on name of hydrocarbon is dropped



Common names are frequently used too.

HC

H3C

O

HC

H

O

IUPAC methanal ethanal propanal

Common formaldehyde acetaldehyde propionaldehyde

H3C CH2C

O

H



Aromatic aldehydes are named as benzaldehydes.

CH

O

Benzaldehyde

CH

O

Cl

Cl

2,4-dichlorobenzaldehyde


13.4 Naming Ketones

Ketones have two hydrocarbon substit-uents on the carbonyl group. The carbonyl group can be in a ring.

H3CC

CH3

OC

O

C

O


13.4 Naming Ketones

Suffix is “-one”

1. Find longest chain that bears carbonyl

2. Number carbon chain so carbon bearing C=O has lowest possible number; it cannot be #1




13.4 Naming KetonesCommon names are frequently used.

They are formed by naming the alkyl substituents on the carbonyl, usually in alphabetical order.

IUPAC

Common

H3CC

CH3

O

H3CC

CH2

O

CH3

2-propanone 2-butanone

acetone methyl ethyl ketone (MEK)


13.4 Naming Ketones

Compounds with carbonyl groups in rings are named as cycloalkanones. The carbonyl carbon is #1; this locant is understood and not given.

C

O

C

OCH3

CH3

Cl

cyclohexanone 4-chloro-2,2-dimethylcyclopentanone


13.4 Naming Ketones

Aromatic ketones are named as phenones, or as ketones with phenyl and alkyl substituents.

C

O

CCH3

O

benzophenone acetophenone

diphenyl ketone methyl phenyl ketone


13.4 Naming Ketones

Acetyl groups are carbonyl groups bonded to methyl groups. “Acet-” and “aceto-” appear often in names of carbonyl compounds.

H3CC

O

acetylgroup

H3CC

H

O

acetaldehyde

H3CC

CH3

O

acetone

H3CC

OH

O

aceticacid


13.3,5 Properties of Aldehydes and Ketones

Aldehydes and ketones have similar prop-erties and undergo similar reactions. These will be considered together.

Aldehydes and ketones are polar, but are not hydrogen bond donors. Their boiling points are intermediate between alcohols and alkanes/ethers.


13.3,5 Properties of Aldehydes and Ketones

Aldehydes and ketones have similar prop-erties and undergo similar reactions. These will be considered together.


13.3,5 Properties

Aldehydes and ketones can act as hydrogen bond acceptors. Small compounds are appreciably soluble in water.

Formaldehyde, acetaldehyde, and acetone are completely soluble in water.

C O H OH


13.3,5 Reactions

Aldehydes are generally more reactive than ketones, and can undergo some reactions that ketones do not. There are more sim-ilarities than differences.


13.3,5 Reactions

Aldehydes are easily oxidized to carboxylic acids.

Ketones are not easily oxidized.

C

O

H O2C

O

OH

benzaldehyde,viscous liquid,

almond fragrance

benzoic acid,white solid,

no fragrance


13.3,5 Reactions

Tollens’ test is an oxidation of aldehydes by Ag1+, which is reduced to silver metal.

RC

H

O+ Ag1+ NH3

H2O RC

OH

O+ Ag(metal)


13.3,5 Reactions

Aldehydes and ketones can be reduced to alcohols.

RC

H

O[H2]

OH

CHR

H 1° alcohol

R1CR2

O[H2]

OH

CR2R1

H 2° alcohol


13.3,5 Reactions

Catalytic hydrogenation works, but more often NaBH4 or LiAlH4 is used. These compounds behave as sources of hydride anion, H1–.

B

H

H

H

HNa Al

H

H

H

HLi


13.3,5 ReactionsHydration is addition of water across the

C=O bond. It is similar to addition across a C=C bond.

Aldehydes hydrate more readily than ketones. Formaldehyde hydrates completely. Formalin is a solution of hydrated formaldehyde.

R1 CO

H+ H2O R1 C

H

OH

OH

hydrated aldehyde


13.3,5 Reactions

Alcohols can add across a C=O bond. The product is called a hemiacetal.

Ketones undergo the same reaction, but less readily. The product is sometimes called a hemiketal. We’ll call both types hemiacetals.

R1 CO

H+ HO R2 R1 C

H

OH

O R2

hemiacetal


13.3,5 Reactions

Hemiacetals have ether and hydroxyl groups on the same carbon.

The two structures are in equilibrium, and the hemiacetal can be difficult to isolate.

R1C

R2

O+ R3OH

O

CR2R1

O

R3

HR2 can be H


13.3,5 Reactions

Carbonyl compounds with hydroxyl groups three or four carbons away readily form cyclic hemiacetals.

R1C

CH2

O

CH2 CH2 O HO

OHR1

R1C

CH2

O

CH2 CH2 CH2 OO

H

OHR1


13.3,5 ReactionsIn the presence of excess alcohol, acetals

form. Acetals of ketones may be called ketals.

The equilibrium is not favorable for the reac-tion. Catalysis speeds it up, and water removal drive it to completion.

R1C

R2

O+ 2 R3OH

O

CR2R1

O

R3

R3

R2 can be H

H3O1+ catalyst+ H2O

heat− H2O


13.3,5 Reactions

Acetals have two ether groups on the same carbon. Like ethers, they are not very reactive.

O

CR2R1

O

R3

R3


13.3,5 Reactions

Acetals can be converted back to the parent aldehydes or ketones with water and an acid catalyst.

O

CR2R1

O

R3

R3

+ H2OH3O1+ catalyst

R1C

R2

O+ 2 R3OH


13.3,5 Reactions

Diols give cyclic acetals.

C

O

+ HO CH2 CH2 OHheat− H2O

H3O1+ OO

ethylene glycol


Common AldehydesFormaldehyde, the simplest aldehyde, is used

for sterilizing apparatus and as an embalm-ing fluid.

It is also a component of synthetic resins, e.g. phenol-formaldehyde (Bakelite), and melamine-formaldehyde (Formica).

HC

H

O

formaldehyde

+ H2OH

CH

OHHO

formalin


Common AldehydesAldehydes are components of flavors and odors.

CO

H

benzaldehyde,almond oil

CO

HHO

OH3Cvanillin

CC

C

O

H

H

H

CO

HCH

H3C

H3C

cinnamaldehyde cuminaldehyde


Common Ketones

Simple ketones are solvents and degreasers.

Simple aldehydes are too reactive and toxic to be used as solvents.

H3CC

CH3

O

H3CC

CH2

O

CH3

acetone methyl ethyl ketone (MEK)


Common Ketones

Aromatic ketones are used as photoinitiators for resin that cure in ultraviolet light, such as those in dental sealants.

C

O

benzophenone

C

OOH

hydroxycyclohexyl-phenyl ketone


Common Ketones

Ketones are functional groups in some steroid hormones.

O

O OH

O

cortosone

OH

O

O

progesterone


13.6 Carboxylic Acids

Carboxylic acids have a carboxyl group (COOH) on a hydrocarbon chain; R–COOH

The carboxyl group has a hydroxyl group on a carbonyl carbon.

RC

OH

O


13.6 Naming Carboxylic Acids

Suffix is “-oic acid”

1. Find longest chain that bears –COOH

2. Number carbon chain so –COOH is #1




13.6 Naming Carboxylic AcidsSimple carboxylic acids are often known by

common names.

OHC

H3C

O

HC

OH

O

IUPAC methanoic acid ethanoic acid

butanoic acid

Common formic acid acetic acid

butyric acid

H3C CH2 CH2C

O

OH

IUPAC

Common



Aromatic carboxylic acids are named as derivatives of benzoic acid.

C

O

OHC

O

OH

benzoic acid

OH

2-hydroxybenzoic acida.k.a. salicylic acid



Aromatic dicarboxylic acids are named as phthalic acids, because the ortho isomer was originally made from naphthalene.

C

O

OH

C

O

OH

phthalic acid,ortho-phthalic acid

C

O

HOC

O

OH

isophthalic acid,meta-phthalic acid

C

O

OH

C

O

HO

terephthalic acid,para-phthalic acid


13.7 Properties of Carboxylic Acids

Carboxylic acids with up to nine carbon atoms are liquids with pungent odors.

Acetic acid, in vinegar, is a good example. “Acet” comes from “vinum acetum,” sour wine.

Larger molecules are waxy solids, as are aromatic carboxylic acids.



Carboxylic acids with up to nine carbon atoms are liquids with pungent odors.

H3C-CH2-CH2 CO

OH

H3C CO

OH

H3C-(CH2)4 CO

OH

Acetic acid

Butyric acid

Caproic acid

Vinegar

Rancid butter

Goat cheese


13.7 Properties of Carboxylic AcidsCarboxylic acids are polar, and form dimers

through hydrogen bonding. They have have quite high melting and boiling points.


13.7 Properties Carboxylic

Acids



Carboxylic acids are slightly more sol-uble in water than alcohols with the same number of carbons.


13.7 Acidity of Carboxylic Acids

Carboxylic acids are proton donors.

When R is alkyl, Keq is about 10–5.

Keq = [H3O1+][RCOO1–]

[RCOOH][H2O]

Less than 5% of the molecules are ionized.

R CO

O+ R C

O

OH

OHH

OHH

+H

Carboxylateanion

Hydroniumcation



In organic chemistry, we often show ionic charges on specific atoms. These are called “formal charges.”

CH3 CO

OO

HH

H

Acetateanion

Hydroniumcation

OHH

H

1+

CH3 CO

O

1−



In strong base, ionization is complete.

Carboxylate anions are stabilized by resonance.

R CO

O+ R C

O

OHO +

Carboxylateanion

H

Hydroxideanion

OHH

R CO

OR C

O

O



In strong acid, the carboxylate is completely protonated.

+ OHH

R CO

O

OHH

+H

R CO

O H


13.7 Naming Carboxylate Salts

Carboxylate anions are named as the “-ate” anion of the conjugate acid.

CH3 CO

O

acetate

CH3 CH2 CH2 CO

OC

O

O

butanoate(butyrate)

benzoate


13.7 Naming Carboxylate Salts

Ionic compounds are also called “salts.” Those that contain carboxylate anions are named with the cation (usually a metal) followed by the name of the carboxylate.

C

C

O

O

O

OCu2+CH3 C

O

ONa C

O

OK1+

Sodium acetate Potassium benzoate Copper (II) phthalate


13.7 Reactions of Carboxylic AcidsAcid-base reactions:

Carboxylic acids equilibrate with their conjugate bases in water.

RCOOH + H2O RCOO1– + H3O1+

Carboxylic acids deprotonate to carboxylate salts in strong bases.

RCOOH + OH1– RCOO1– + H2O

Carboxylate anions are protonated in strong acids.

RCOO1– + H3O1+ RCOOH + H2O


13.7 Reactions of Carboxylic AcidsCondensation reactions:

Condensation reactions are reactions in which two molecules combine into one, with the expulsion of a small molecule such as water.

The dehydration of alcohols to form ethers is a condensation reaction.

R CH2 O H + H O CH2 RH2SO4

140° C

R CH2 O CH2 R + H2O


13.7 Reactions of Carboxylic Acids

Esters are produced by the condensation of a carboxylic acid and an alcohol.

Keq is often near 1. In the classic Fischer Esterification, H2SO4 is the catalyst.

CO

OH+ HO CH3 C

O

O CH3

+ H2OH1+



Lactones are cyclic esters. They are formed by intramolecular conden-sations of hydroxy acids.

HO CH2 CH2 CH2 CO

OH

catalyst

OC O + H2O

γ-butyrolactone

HO CH2 CH2 CH2 CH2 CO

OH

catalyst+ H2O

δ-valerolactoneOC O



Amides are produced by the condensation of a carboxylic acid and ammonia or an amine.

The amine must have at least one hydrogen, or water cannot form.

CO

OH+ C

O

N CH3

+ H2OH1+

HNCH3

CH3

CH3

heat



Direct formation of amides from carboxylic acids and amines is complicated by the acid-base reaction between reactants.

“Heat” means > 200C (>400F) to decompose the salt and form the amide.

mild

conditionsC

O

O+

HC

O

ON

CH3

HCH3

+ NCH3

HCH3

H


Important Carboxylic Acids



H3C CO

OH

H CO

OH

Formic acid, simplest carboxylicacid, used in antimicrobials andleather tanning

Acetic acid, the most commoncarboxylic acid, found in vinegarand widely used in industry.

C CO

OH

H

CHH

C CO

OH

H3C

CHH

Acrylic acid, simplest unsaturatedcarboxylic acid, used to makewater-soluble polymers

Methacrylic acid, used to makeesters and polymeric derivatives





CO

OH

C

C

O

OH

O

OH

CO

HO

O

OH

Benzoic acid, simplest aromaticcarboxylic acid, used as a foodpreservative and industrial feed.

o-Phthalic acid, generally usedas its anhydride, in plasticisersand dyes

Terephthalic acid, used in polyester plastics and fibers





CH3 CH

OH

CO

OH

Lactic acid, "milk acid," is importantin metabolism in its anionic form

CH3 C

O

CO

OH

Pyruvic acid is a metabolite of glucosethat enters the Citric Acid Cycle. The name comes from "pyrolysis of grapes."

Salicylic acid, "willow acid," is anantiinflammatory and antipyretic; esters are aspirin and wintergreen

C

O

OH

OH





C

O

OH

Stearic acid, "typical" saturated fatty acid

Oleic acid, from olives, monounsaturated fatty acid

O

OH

Linoleic acid, from vegetable oils, polyunsaturatedfatty acid. Essential in diet; used in oil paints

O

OH

Linolenic acid, from vegetable oils, polyunsaturatedfatty acid. Essential in diet; used in oil paints

O

OH


13.8 Esters

Esters are derivatives of carboxylic acids.

They have an alkoxy group (–OR) on a carbonyl carbon.

R1C

O

OR2


13.8 Naming Esters

Esters are condensation products of alcohols and carboxylic acids. They are named as alkyl alkanoates. The alkyl group is de-rived from the alcohol; the alkanoate is de-rived from the acid. The -oic acid suffix or the acid is replaced by -ate.

CO

OH+ HO CH3 C

O

O CH3

+ H2OH1+

Benzoic acid Methanol Methyl benzoate


13.8 Naming Esters

Esters are condensation products of alcohols and carboxylic acids. They are named as alkyl alkanoates. The alkyl group is de-rived from the alcohol; the alkanoate is de-rived from the acid. The -oic acid suffix or the acid is replaced by -ate.

CH3 C

O

OH + H2O CH2 CH3 CH3 C

O

O CH2 CH3 + H2O

Ethanoicacid, a.k.a.Acetic acid

Ethanol Ethyl ethanoate, a.k.a.Ethyl acetate

+ HO CH3 + H2O

Methanol

CH3 CH2 C

O

OH

Propanoic acid

CH3 CH2 C

O

O CH3

Methyl propanoate


13.9 Properties of Esters

Esters are polar, but cannot form hydrogen bonds. They are slightly soluble in water. Boiling points are somewhat lower than those of structurally similar ketones.

CH3−CH−CH2−CH3

CH3

CH3−CH−CH2−CH3

OH

CH3−C−CH2−CH3

O

CH3−C−O−CH3

O

bp = 28oC bp = 57oC bp = 80oC bp = 99oC

OO

O

bp = 218oCbp = 199oC


13.9 Properties of Esters

Most simple esters are liquids. Many have fruity or floral fragrances.

H3CC

O

O

CH2 CH2 CH

CH3

CH3

Isoamyl acetateBanana scent

C

O

OCH3

OH

Methyl salicylateWintergreen scent


13.9 Reactions of EstersHydrolysis:

The main reaction of esters is hydrolysis (breaking with water). It is the reverse of the condensation reaction.

Like formation of the ester, Keq is ~1. Excess water increases the amount of hydrolyzed product.

CO

OH+ HO CH3C

O

O CH3

+ H2OH1+

Benzoic acid MethanolMethyl benzoate


13.9 Reactions of Esters

Hydrolysis of esters in base is called saponification, a.k.a. soap-making!

One uses at least an equivalent of OH1–, and the acid is isolated as its carbox-ylate salt. Formation of the salt drives the reaction to completion.

CO

O+ HO CH3C

O

O CH3

+ NaOHH2O

Sodiumbenzoate

Methanol

+ Na


13.9 Reactions of Esters

Transesterification:It is often easier to prepare complex esters or amides from simple esters than from the acids.

C CO

O

H3C

CHH

2 + HO CH2 CH2 OHSnO(C4H9)2

C CO

O

H3C

CHH

CCO

O

CH3

C HH

CH2 CH2

+ 2 CH3OH

Ethylene glycol dimethacrylate

CH3


13.9 Reactions of EstersTransesterification:

It is often easier to prepare complex esters or amides from simple esters than from the acids.

CH3(CH2)16 CO

O CH3

2

methyl stearate

+ H2N CH2 CH2 NH2heat

CH3(CH2)16 CO

N CH2

ethylene diamine

HCH2 N

H

CO

(CH2)16CH3 + 2 CH3OH

ethylene bis stearamide


Important Esters


H3C CO

O CH2 CH3

Ethyl acetate, industrial solvent, found in nail polish remover

CHOO

O CO

CH3

Acetylsalicylic acid, Aspirin, acetateester of salicylic acid; antiinflammatoryand antipyretic, not as irritating to thestomach as salicylic acid

C

O

O

OH

CH3 Methyl salicylate, rubifacient (causesreddening of skin by dilating capillaries)for topical pain relief; oil of wintergreen


Important Esters


CH O

CH2 O

CH2 O

C

O

R2

C

O

R1

C

O

R3

Triglyceride esters,important lipids


13.10 Amides

Amides are derivatives of carboxylic acids.

They have an amine group on a carbonyl carbon. Any of the R’s can be H.

R1C

O

NR2

R3


13.10 Amides

Amines are classified by the number of carbon atoms bonded to the nitrogen atom.

Primary (1°) Secondary (2°) Tertiary (3°)

R1C

O

N

H

HR1

C

O

N

H

R2 R1C

O

N

R3

R2


13.10 Naming Amides

Suffix is “amide”

1. Root is derived from carboxylic acid

2. IUPAC names for secondary and tertiary amides involve use of the prefix “N-” for the amine substituents. If the same group appears twice, use “di-” and prefix.

3. IUPAC names for amides of simple acids allow the acid’s common name to be used.


13.10 Naming Amides

Suffix is “amide”

1. Root is derived from carboxylic acidH

CNH2

O

Methanamide,Formamide

H3CC

N

O

CH2 CH3

H

N-ethylethanamide,N-ethylacetamide

C

O

NCH3

CH3

N,N-dimethyl-benzamide

CH3 CH2 CO

NH

2-methylbutanamide


13.10 Naming Amides

Compounds in which a carbonyl group is flanked by two nitrogen atoms are called ureas.

N

NN

NOON

CN

O

H

H

H

H

H

H H

H

Urea Glycouril


13.10 Naming Amides

Compounds in which carbonyl groups appear on either side of the nitrogen are called imides. Cyclic imides are more common than straight-chain molecules.

CN

C

O

O

H

Phthalimide

CN

C

O

O

Br

N-bromosuccinimide,NBS (Br2 source)

CN

C

O

O

CH2 CH3

N-ethylmaleimide,NEM, used in enzyme

research


13.11 Properties of Amides

Amides have resonance structures that cause the nitrogen atom to be trigonal planar, sp2.

Rotation about the CN bond is restricted.

R1C

O

N

H

R2 R1C

O

N

H

R2


13.11 Properties of Amides1 and 2 amides have

strong dipoles and hydrogen bonds.

For 2 amides, the fa-vored conformation has the H atom op-posite the O atom. The dipole-dipole forces and hydro-gen bonds are quite strong.

R1C

O

N

H

R2

R1C

O

N

H

R2


13.11 Properties of Amides1 and 2 amides have the highest melting and

boiling points of common compounds. 3 amides are usually high-boiling liquids.

RC

OH

O

RC

N

O

H

H

RC

N

O

CH3

H

RC

N

O

CH3

CH3

101° 8°

210° 3°

199° −3°

153°−61°

BPMP

119° 17°

222° 81°

206° 28°

166°−20°

BPMP

BPMP

249°123°

N/A128°

N/A 78°

N/A 45°

R = H

R = CH3

R = C6H5


13.11 Properties of AmidesAll amides are hydrogen-bond acceptors.

Those with fewer than 6 carbons are freely soluble with water.


13.11 Reactions of Amides

Hydrolysis:The main reaction of amides is hydrolysis. The reaction always requires acid or base.

R1C

O

N

R3

R2 + H2OR1

C

O HN

R3

R2

OH+

slow,Keq << 1


13.11 Reactions of Amides

Formation of the ammonium cation in acid or the carboxylate anion in base drives the equilibrium to the right.

R1C

O

N

R3

R2 + H3O1+ + H2OR1

C

ON

R3

R2

OH+

H

H

R1C

O

N

R3

R2 + OH1− + H2OR1

C

O

O+

HN

R3

R2


Important AmidesSimple amides: various small molecules

HC

N

O

CH3

CH3

Dimethyl formamide, DMFhigh-boiling polar solvent

NC

O

CH3

N-methylpyrrolidone, NMP,high-boiling polar solvent

NC

N

O

H

H

H

H

Urea, metabolite of aminoacids, fertilizer


Important Amides-lactam antibiotics:

Penicillins, cephalosporins, and related antibiotics contain the -lactam group.

R2

OHO

N

NR1

O

O

HS

C N

S CH3

CH3

CO

OH

HH

NC

H

O

R

Cephalosporin

O

Penicillin

C NO H

-lactam


Important Amides

Barbiturates:

Barbituric acid is the parent compound for many central nervous system depressants. They are used as sedatives and anesthetics.

Barbituric Acid

N

O

N

O O

HH N

O

N

O O

HH

Phenobarbital

CH3CH2 C6H5


13.12 Condensation Polymers

Condensation reactions between polyfunctional carboxylic acids and alcohols or amines produce a wide variety of polymers. They are called condensation polymers or step-growth polymers because of how they form.

Polymers formed from alkenes are called chain-growth polymers or addition polymers.



Polyesters are formed in reactions between diacids and diols.

Polyamides are formed in reactions between diacids and diamines.





C

O

HO

C

O

OH+ HO CH2 CH2 OH

catalyst− H2O

terephthalic acid

ethyleneglycol

C

O

HO

C

O

O CH2 CH2 OC

O

C

O

O CH2 CH2 OH

n

Poly(ethylene terephthalate), PETE


Important Polyesters



C

O

C

O

O CH2 CH2n

Polyethylene terephthalate, PETE, "polyester" in plastics and fiber, Dacron

CH2 C

CH3

CO OH3C n

Poly(methyl methacrylate),PMMA, polymer used asglass, Lucite , Plexiglas

C

CH3

O C

O

O

CH3 n

Polycarbonate, polymerused as glass, very highimpact resistance



Synthetic and natural polyamides are important.Nylon 6,6 was developed by Wallace Carothers

of DuPont as a silk replacement in 1935.

HOC

(CH2)4C

OH

O O+ H2N (CH2)6 NH2

− H2O

HOC

(CH2)4C

N

O O

H

(CH2)6 NH

C

O

(CH2)4C

O

N

H

(CH2)6 NH

H

Adipic acid

Nylon 6,6

n

Hexane Diamine

285°



In the “nylon rope trick” polymer forms at the interface of a water solution of hexane di-amine and an organic solution of adipoyl chloride (adipic acid on steroids!).



Nylon 6 was developed in Germany. It is made by ring-opening, rather than condensation.

Nylons are very strong fibers because of inter-chain hydrogen bonding. There are regions of microcrystallinity, highly or-dered chain segments, in the material.

NC

O

H260°CN2

C(CH2)5

O

NC

H

O

(CH2)5 NH n

Caprolactam



From Wikipedia



Aramids are polyamides with aromatic com-ponents. They are even stronger than Nylon 6,6, and are used for demanding applications, such as armor.

CO

NH

NH

CO

C

n

Kevlar , high strength aramid Nomex , heat-resistant aramid

O

NH

C C

O

N

O

H

N

H n



Polyurethanes are polymeric carbamates. They are resilient, elastomeric, and can be made into foams. There are many structures, but most involve reactions between diisocyan-ates and diols.

+ HO R OH

Methylene diphenylisocyanate (MDI)

CH2

NC

O

NC

O

CH2

NC

NC

HH

O

O R O

O

O

n



Proteins and peptides are naturally-occurring polyamides formed from amino acids.

There are ~20 amino acids with different R’s.

Proteins are long polymers, n > 50 Peptides are short polymers, n < 50

HN

H

CH

R

C

O

OH HN

H

CH

R

C

O

N

H

CH

R

C

O

N

H

CH

R

C

O

OH

n


Important Polyamides

Proteins and peptides are naturally-occurring polyamides formed from amino acids.

NC

H

O

(CH2)5 N

H

C

n

O

NC

(CH2)4C

N

O O

H

(CH2)6 N

H

C

O

Nylon 6,6

nH

Nylon 6

C

O

N

H

CH

R

C

O

N

Hn

Polypeptides,Proteins

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