Copyright © Houghton Mifflin Company. All rights reserved.3–13–1 12 Hydrocarbon Derivatives I Compounds with carbon-heteroatom single bonds Alkyl halides.

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

12 Hydrocarbon Derivatives I

Compounds with carbon-heteroatom single bonds

Alkyl halides

Alcohols

Phenols

Ethers

Thiols

Amines


12.2 Halogenated Hydrocarbons

Halogenated hydrocarbons have halogen atoms (–F, –Cl, –Br, –I) on a hydrocar-bon skeleton; R–X

1-bromobutane

H C C C C Br

H

HH

H

H

H

H

H


12.2 Naming Halogenated Hydrocarbons

Halogens are treated as substituents, like alkyl substituents. The prefixes are fluoro–, chloro–, bromo–, iodo–.

C C

H

H

H Cl

Cl

Cl

1,1,1-trichloroethane

H3C C CH3

CH3

Br

2-bromo-2-methylpropane


12.2 Properties of Halogenated Hydrocarbons

Many halogenated hydrocarbons are liquids with densities greater than 1.00 g/mL.

Halogenated hydrocarbons are not very polar, and are not soluble in water. They are good solvents for hydrocarbons, and are used to remove grease.

Halogenated hydrocarbons are not flammable, and are used in fire extinguishers (halons).


Common Halogenated Hydrocarbons

Some halogenated hydrocarbons are used as inhalation anesthetics.

C

H

Cl Cl

Cl

trichloromethane,a.k.a chloroform

F C C H

F

F

Cl

Br

2-bromo-2-chloro-1,1,1-trifluoroethane,a.k.a halothane



Some halogenated hydrocarbons are used as refrigerants. The chlorofluorocarbons destroy atmospheric ozone. All are green-house gases.

C

F

Cl F

Cl

C C

F

F

F H

H

F

1,1,1,2-tetrafluoroethane,a.k.a. R-134a

dichlorodifluoromethane,a.k.a. R-12



Several halogenated hydrocarbons have been used as pesticides. Many have adverse environmental effects.

C

ClCl

H CCl Cl

Cl 4,4'-(2,2,2-trichloroethane-1,1-diyl)bis(chlorobenzene)

a.k.a. DDT, dichlorodiphenyltrichloroethane


12.3 Alcohols

Alcohols have a hydroxy(l) group (–OH) on an alkyl chain; R–OH

Ethanol, Ethyl alcohol

HOCC

H

HH

H

H HOC

CC

C

C C

HH

H

H H

C

C C

C

CC

O C

H

H

H H

HH

H

H


12.3 Naming Alcohols

Suffix is “-ol”

1. Find longest chain that bears –OH

2. Number carbons on chain so carbon bearing –OH has lowest possible number

3. Locate –OH by number of carbon

4. Locate and name any other substituents

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



H C C C C OH

H

HH

H

H

H

H

H

Name these:

H3C C CH3

CH3

OH

Draw structures for:

2-methyl-1-propanol 2-butanol



Name this!

C

OH

CH2 CH2 CH3CH2

CH2

CH2 CH2 CH2 CH3

CH3


12.4 Properties of Alcohols

Properties are driven by hydrogen bonding and polarity.

Alcohols up with up to 6 carbons are at least somewhat soluble in water.

Alcohols have higher melting and boiling points than alkanes of

similar molar mass.


12.4 Properties of AlcoholsHydrogen bonding among alcohol molecules





As alkyl chain on alcohol gets larger, properties become more alkane-like


12.4 Properties of AlcoholsMelting and Boiling Points of Alkanes and Alcohols

-200

-100

0

100

200

300

400

0 5 10 15 20Number of Carbons

Temperature, °C

Alkane MP, °CAlkane BP, °CAlcohol MP, °CAlcohol BP, °C



Classification of alcohols

Primary (1)

Secondary (2)

Tertiary (3)

R CH2 O H

CH O HR1

R2

C O H

R1

R2

R3


12.4 Reactions of Alcohols

Alcohols can dehydrate (lose H2O) to produce alkenes.

Tertiary alcohols don’t react.

C C C

H3C

H3C

H

H

OH

H

H

H

H2SO4

180o CC

H3C

H3CC

C

H

HH

H + CC C

H

H

C

C

HH H

H H

HH H

+ H2O

Major Minor



Alcohols can dehydrate to produce ethers

This is most useful with primary alcohols; the alkene may also form.

H3C CH2 O H + H O CH2 CH3

H2SO4

140o C

H3C CH2 O CH2 CH3 + H2O



Alcohols oxidize to form C=O bonds.

The reaction is formally loss of H2.

Oxidizing agents:

KMnO4, K2Cr2O7

C

H

O H

R1

R2[O]

C O

R1

R2

H2O+



Different classes of alcohol react differently.

Primary alcohols:

AldehydeCarboxylic

acid

It can be hard to stop at aldehyde stage.

CR O

H

H

H[O]

CR H

O[O]

CR O

O

H



To make aldehyde, use CrO3 in pyridine. Keep water out of the reaction!

C

H

R

H

C

H

H

O H[O]

RC

H

O




Secondary alcohols:

Ketone

C O H

R1

R2

H

[O]C

O

R1R2




Tertiary alcohols:

Can’t react, no H on C!

C O H

R1

R2

R3

[O] No RXN


Common Alcohols

Methanol CH3–OH Wood alcohol; used as solvent, reactant

Ethanol CH3–CH2–OH Grain alcohol; used as solvent, reactant, beverage!

2-Propanol CH3–CH(OH)–CH3

Isopropanol Rubbing alcohol; usedfor sterilization of in-jection sites


Common Alcohols

Ethanediol HO–CH2–CH2–OH

Ethylene glycol Antifreeze; poisonous

Cholesterol Important biomolecule

OH

CH3

H H

CH3

CH3


12.3 a Phenols

Alcohols have a hydroxy group on an aromatic ring; –OH

Phenol, a.k.a carbolic acid

HOCC

H

HH

H

H HOC

CC

C

C C

HH

H

H H

C

C C

C

CC

O C

H

H

H H

HH

H

H


12.3 a Naming Phenols

Suffix is “phenol”

1. Carbon bearing hydroxyl is #1

2. Number carbons on ring so carbon bearing substituent has lowest possible number

OH

H3C CH3

Cl

OH


12.3 a Naming Phenols

Phenols with several hydroxyls have cool names

Catechol Resorcinol Hydroquinone

Pyrogallol Phloroglucinol 1,2,4 Benzenetriol

OH

OH

OH

OHOH

HO

OH

OH

OH

OH

OHHO HO

OH

OH


12.4 a Properties of Phenols

Properties are driven by hydrogen bonding, polarity, and aromaticity

Most phenols are solids

Phenols are weak acids


12.4 a Properties of Phenols

OH

O

H


12.4 a Reactions of Phenols

Phenols are weak acids and undergo acid- base reactions.

Phenoxide Hydronium

anion cation

OH

O +H

OH

H



Dihydroxyphenols oxidize to form quinones.

Hydroquinone Benzoquinone

Hydroquinones are antioxidants; they react with oxidizing agents and protect other com-pounds from oxidation.

OHHO[O]

O O H2O+



Dihydroxyphenols oxidize to form quinones.

Vitamin C (ascorbic acid) acts like hydroquinone.

O

OHHO

OR [O]O

O O

OR+ H2O


Common Phenols

OH

Phenol, a.k.a.Carbolic acid

Disinfectant,Local anesthetic

C

O

OH

OH

Salicylic acidAnalgesic, basisfor aspirin andBen-Gay

OHButylatedhydroxy-toluene, a.k.a. BHT

Preservative,antioxidant


Common Phenols

CH3H3C

HO OH

Bisphenol-A

HO

H H

CH3 OH

Estradiol

Used in epoxides andpolycarbonate plastics,has estrogenic properties

A major component ofestrogen


12.5 Ethers

Ethers have oxygen atoms bonded to two carbon atoms.

CH3 CH2 O CH2 CH3

Diethyl ether


12.5 Naming Ethers

Common names of ethers are formed by naming the hydrocarbon group on either side of the oxygen atom and adding the word “ether.” The hydrocarbons are named in alphabetical order.

CH3 CH2 O

Ethyl phenyl ether

CH3 O CH3

Dimethyl ether


12.5 Naming Ethers

Cyclic ethers have interesting names; these turn up in carbohydrates.

C C

CO

CC C

CO

C C

CC

C

CO

H

H H

HH

H

HHH

H

H

H H H

HHH H

Furan Tetrahydro-furan (THF)

Pyran


12.5 Naming Ethers

Ethylene oxide and propylene oxide, cyclic ethers with three-membered rings, are important oddities. Such ethers are called epoxides.

O O CH3

ethylene oxide propylene oxide


12.5 Naming Ethers

Cyclic di- and tri-ethers:

OO

O

O

O O

O OO

Dioxolane Dioxane Trioxane Dioxepane


12.5 Properties of Ethers

Ethers have boiling points similar to those of hydrocarbons with similar structures.

Like hydrocarbons, they are flammable.

CH3 CH2 O CH2 CH3 CH3 CH2 CH2 CH2 CH3

Boiling point 35°C Boiling point 36°C


12.5 Properties of EthersEthers have water solubilities similar to those

of isomeric alcohols. They are hydrogen bond acceptors.


12.5 Reactions of EthersEthers are not particularly reactive. They are

good solvents for certain reactions.

Ethers form explosive hydroperoxides in the presence of oxygen. Ethers are treated with antioxidants to prevent this.

C C

CO

CH

H

HHH

H

H

H

+ O2 C C

CO

CH

O

HHH

H

H

HO H


12.5 Reactions of Ethers

Polymeric ethers are made from ring-opening reactions of epoxides, which are much more reactive than most ethers.

HO [CH2 CH2 O]n H HO [CH2 CH O]n H

CH3

Poly(ethylene glycol) (PEG)Carbowax

Poly(propylene glycol) (PPG)


Common Ethers

Diethyl ether and chloroform were used as anesthetics in the 1840’s. Fluorinated ethers are not flammable and have fewer side effects than either of these.

CC

OC

F FF

FCl

F

F

H

Enflurane

CC

OC

F ClF

FF

F

F

H

Isoflurane

CC

OC

F HF

FF

F

F

H

Desflurane

CC

OC

C HF

FF

H

F

HFF F

Sevoflurane


Common Ethers

Diethyl ether and tetrahydrofuran (THF) are very useful solvents. Unlike most ethers, THF is freely soluble in water.

CH3 CH2 O CH2 CH3

Diethyl ether

C C

CO

CH

H

HHH

H

H

H

Tetrahydrofuran (THF)


Common Ethers

Bisphenol-A diglycidyl ether (BADGE) is the “resin’ in most epoxy glues.

CH3H3C

O OOO


12.6 Thiols

Thiols are the sulfur analogs of alcohols. The SH is called a sulfhydryl group.

Another name for thiols is mercaptans, from “mercury capture.” Thiols and sulfide ions react with heavy metals.

R OH

R SH

Alcohol Thiol


12.6 NamingThiols

Thiols are named like alcohols. The suffix for the sulfhydryl group is “-thiol.” The -e at the end of the alkane name is retained.

CH3 CH2 CH

OH

CH3 CH3 CH2 CH

OH

CH3

2-butanol 2-butanethiol


12.6 Properties of Thiols

Thiols are polar, but are not capable of hydrogen bonding.

Boiling points of thiols are lower than those of analogous alcohols.

Small thiols are often have strong odors.


12.6 Properties of Thiols

1-butanethiol is added to nat-ural gas as an odorant, so leaks can be detected.

Skunk odor is due to thiols.


12.6 Reactions of Thiols

Thiols are weak acids and undergo acid-base reactions.

ethanethiol thiolate anion

+ OH1– + H2OCH3 CH2 S H CH3 CH2 S

CH3 CH2 S + H2O CH3 CH2 S + H3OH



Thiols undergo oxidative coupling to form disulfides.

This reaction is important in protein chemistry.

R S H + H S R[O]

R S S R + H2O

thiols disulfide



Oxidative coupling is reversible. Reducing agents, [H2], restore the thiols.

These reactions are involved in “permanents” and straightening agents for hair.

R S S R

disulfide

[H2]R S H + H S R

thiols


12.7 Amines

Amines contain nitrogen. They are organic derivatives of ammonia.


12.7 Naming AminesCommon names of amines are formed by

naming the alkyl groups attached to the nitrogen in alphabetical order and adding the suffix “amine.”

CH3 CH2 NH2

ethylamine

CH3 CH2 N

H

CH2 CH3

diethylamine

NCH3

CH2 CH3ethylmethylphenylamine


12.7 Naming AminesAromatic amines are called anilines.

The prefix “N-” locates alkyl groups on nitrogen.

NH H

NH CH2 CH3 N

H3C CH3

aniline N-ethylaniline N,N-dimethyl-aniline


12.7 Naming AminesCyclic aromatic amines with nitrogen in the

ring are common in biological molecules.

N

N

N

N

N

N N

N

pyridine pyrimidine pyrazine triazine

N

N

N

H H

pyrrole imidazole


12.7 Naming Amines

Fused aromatic rings that contain nitrogen are also common.

N

N

N

N

N

H

quinoline purine


12.7 Naming Amines

Aliphatic rings that contain nitrogen are also common.

N

N

N

O

N N

H H

H

H H

piperidine piperazine morpholine pyrrolidine

O OHHO

N CH3

morphine


12.8 Structures of Amines

Aliphatic amines have tetrahedral electronic geometry and trigonal pyramidal molecular geometry at the nitrogen atom.

R1N

R2

R3


12.8 Structures of Amines

Aromatic amines have trigonal planar electron-ic geometry and trigonal planar or angular molecular geometry at the nitrogen atom.

The lone pair on pyrrole’s nitrogen is part of the aromatic electron system.

NN

H


12.8 Properties of Amines

Amines are polar molecules. 1 and 2 amines are hydrogen-bond donors. 3 amines are hydrogen-bond acceptors.


12.8 Properties of AminesNitrogen is less electronegative than oxygen,

so amines are less polar than alcohols. Melting points and boiling points are lower than those of alcohols of similar structure.

H3C NH2

Name Formula BP, °C

Methylamine -6.3

Methanol H3C OH

Ethylamine

Ethanol

H3C CH2 NH2

65

17

H3C CH2 OH 78



Aromatic amines follow the same trends.

Amines with 6 or fewer carbon atoms are at least somewhat water-soluble.

Name Formula BP, °C

Aniline C6H5 NH2

MP, °C

C6H5 OHPhenol

-6

41

184

182



Odors are prominent and unpleasant.

Small amines smell like ammonia.

Slightly larger amines smell like dead fish.

H2N CH2 CH2 CH2 CH2 NH2

H2N CH2 CH2 CH2 CH2 CH2 NH2

putrescine

cadaverine


12.8 Reactions of Amines

Amines are weak bases and undergo acid-base reactions.

ammonium ion

R1 N

R2

R3 + H2O R1 N

R2

R3

H

+ OH1−

R1 N

R2

R3 + H3O1+ R1 N

R2

R3

H

+ H2O


12.8 Reactions of Amines

Amines undergo alkylation when reacted with alkyl halides.

Even tertiary amines do this. The prod-ucts are called quaternary amine or ammonium salts or just “quats.”

R1 N

R2

R3 + R4Cl R1 N

R2

R3

R4

+ Cl1−


Common AminesSimple alkyl amines, e.g. methylamine,

have already been mentioned.

Amines from plants are called “alkaloids” because they are basic. They often have physiological effects.

N

NH

CH3

Nicotine, a stimulantfrom tobacco

N

N N

N

CH3OH

O

CH3

H3C

Caffeine, a stimulantfrom coffee and tea


Common Amines

The “bases” in DNA and RNA are amines. They interact by hydrogen bonding.

N

NN

N

sugar

NHH

O

HN N

O

sugar

CH3Adenine

Thymine N

NN

N

O

H

sugarN

H

H

N N

O

N

H

H

sugar

Guanine

Cytosine

Copyright © Houghton Mifflin Company. All rights reserved.3–13–1 12 Hydrocarbon Derivatives I Compounds with carbon-heteroatom single bonds Alkyl halides.

Documents

alcohols alcohols

properties of alcohols

naming alcohols slide

bromobutane slide

ethyl alcohol slide

naming alcohols suffix

alkyl substituents

number of carbon