Alcohols and Thiols

8/6/2019 Alcohols and Thiols

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ALCOHOLPHENOLSETHERS


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OBJECTIVES

Name alcohol compound

Understand the importance of

alcohol Compare and contrast alcohol,

phenol and ether


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Importance

Ethanol is a fuel additive, an

industrial solvent and a

beverage Methanol is a flavoring agent

BHT ( butylated

hydroxytoluene) an

antioxidant food additive

Diethyl ether - anesthetic


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ALCOHOLS

can be classified as primary,

secondary and tertiary

Simple alcohols are namedusing the suffix ol


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ALCOHOLS

Alcohols are compounds in

which an OH group has

replaced one of the hydrogen ofan alkane.

Yet they do not behave like

bases such as sodium

hydroxide and potassiumhydroxide.


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NAMINGALCOHOL

Step 1

Select the longest carbon chain

containing the hydroxyl group,and replace thee ending of

the corresponding alkane with -

ol


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NAMINGALCOHOL

Step 2

Name the carbons of the parent

chain beginning at the endnearer the hydroxyl group


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NAMINGALCOHOL

Step 3

Number all substituents

according to their position onthe chain, and write the name

listing the substituents in

alphabetical order


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Common or Radicofunctional

Nomenclature

The common name of an

alcohol is derived by specifying

the alkyl group to which the

OH group is attached, followed

by the separate word alcohol.

CH OH

Methyl alcohol

CH CH CH

OH

Isopropyl alcohol


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Try this!

OH

CH2

CH2

CH2

CH2

CH2

CH3OH


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Nomenclature

Several organic compounds

contains two or more OH

groups.

If compounds contains two

hydroxyl group on adjacent

carbon atoms - glycols


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Nomenclature

CH 2 C H C H 2

HH H

CH 2 C H C H

HH 1,2-propanediol (propylene glycol)

1,2, -propanetriol

(glycerol, glycerin)

1,2-ethanediol (ethylene glycol)H CH2

CH2 H


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PHENOL

used to both as the name of

specific substance

( hydroxybenzene) and as thefamily name for all hydroxy-

substituted aromatic

compounds


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Ethers

Simple ethers that contain no

other functional groups are

named by identifying the two

organic groups and adding the

word ether


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Ethers

If more than one ether linkage is

present, or if other functional

groups are present, the ether

part is named as alkoxy

substiuent on the parent

compound


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SubstitutiveNomenclature

The substitutive nomenclature

of alcohols and thiols involves

an important concept of

nomenclature called the

principal group.

The principal group is the

chemical group on which thename is based, and is always

citedas a suffix in the name.


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For alcohol, theOH is the

principal group and the suffix is

ol while for simple thiols, the

SH is the principal group and its

suffix is thiol.

Note that only certain groups

are cited as principal groups. Ifa compound does not contain a

principal group, it is named as a

substituted hydrocarbon.


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CH3 CH OH Ethane + ol = ethanol

CH3 CH SHEthane + thiol = ethanethiol

Because the suffix of SH begins with a consonant,

the final e of the alkane is retained


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IUPAC Rules

The parent hydrocarbon isthe longest continuouschain containing thefunctional group.

The parent hydrocarbon isnumbered in the direction

that gives the functional group suffix the lowestpossible number.


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IUPAC Rules

CH31

CH CH3

CH34

OH

CH35

CH4

CH3

CH CH1

CH CH3

OH


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IUPAC Rules

CH3 1

CH2

CH3

CH4

OH

CH5

CH3

CH26

CH27

H


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IUPAC Rules

If there is a functional group

suffix and a substituent, the

functional group suffix gets the

lowest possible number.

Notice that a number is not

needed to designate the

position of a functional groupsuffix in a cyclic compound

because it is assumed to be at

the 1-position.


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IUPAC Rules

OH CH21

CH22

CH23

CH24

CH25

Br

CH 3 1 C H2 C H 23 C H 24

OH

C l

2

1

3

CH 3

O H


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IUPAC Rules

CH3 1

C H2

C H23

CH4

CH 3

C H25 C H 26 C H 37

O H


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IUPAC Rules

If there is more than onesubstituent, the substituents arecited in alphabetical order.

Remember that the name of asubstituent is stated before thename of the parenthydrocarbon, and the functionalgroup suffix is stated afterthename of the parenthydrocarbon.


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IUPAC Rules

CH 3 CH CH CH4

CH3

CH CH 31

B r O H

CH CH3


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IUPAC Rules

1

2

3

4

H CH3

CH3

1

2

3

5

4

H

CH2

CH3

CH3


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General Rules for SubstitutiveNomenclature of Organiccompound

Identify the principal groupWhen a structure has severalcandidates for principal group, thegroup chosen is the one given thehighest priority by the IUPAC:

Carboxylic acid > a nhydride > ester >acid halide > Amide > nitrile > aldehyde> Ketone > alcohol, phenol > thiol >

amine


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Identify the principal carbonchain.

The principal chain is the carbon chainon which the name is based. Theprincipal chain is identified by applyingthe following criteria in order until adecision can be made:

greatestnumber ofprincipal groups

greatest number of double and triplebonds

greatestlength

greatestnumber ofothersubstituents


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Number the principal chain

consecutively from one end.

In numbering the principal chain, apply

the f ollowing criteria in order until thereis no ambiguity:

lowest numbers for the principal groups

lowest numbers for multiple bonds, with

double bonds having priority over triplebonds

lowest numbers for other substituents

lowest number for substituent cited first

in the name.


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Begin construction of the name

with the name of the hydrocarbon

corresponding to the principal

chain. Cite the principal group by its suffix and

number; its number is the last one cited

in the name.


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Begin construction of the name

with the name of the hydrocarbon

corresponding to the principal

chain. If there is no principal group, name the

compound as a substituted

hydrocarbon.

Cite the names and numbers of theother substituents in alphabetical order

at the beginning of the name.


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Nomenclature ofEthers and Sulfides

Ethers are compounds in which

oxygen is bonded to two alkyl

substituents while sulfides are

compounds in which the sulfur

is bonded to two alkyl

substituents.


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If the alkyl substituent are

identical, the ether/sulfide is a

symmetrical ether/sulfide,

otherwise, it is an

asymmetrical ether/sulfide.


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R O R R S R

Symmetricalether symmetricalsulfide

R O R R S R

Asymmetricalether Asymmetricalsulfide


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Common Nomenclature

The common name of ether isconstructed by citing asseparate words the two groups

attached to the ether oxygen inalphabetical order, followed bythe word ether.


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Common Nomenclature

CH3CH2 O CH2CH3Diethyl ether

CH3 CH2 O CH 3ethyl methyl ether


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Common Nomenclature

CH3 CH

CH3

O CH CH2 CH3

CH3

CH CH2 O C CH3

CH3

CH3

CH3 CH3


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Common Nomenclature

CH CH2

CH3

CH3 CH2 O


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Common Nomenclature

A sulfide is named in a similarmanner, using the word sulfide.( In older literature, the word

thioether was also used


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Common Nomenclature

CH3CH2 S CH3Ethyl methylsulfide

(CH3)2CH S CH(CH3)2diisopropylsulfide


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Substitutive

Nomenclature

CH3O- CH3CH2O - CH3C(CH3)HO-

Methoxy ethoxy isopropoxy

CH3CH2C(CH3)HO - CH3C(CH3)2O

sec-butoxy tertbutoxy


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Substitutive

Nomenclature

C H C HCH 3

O

C H C H C H 3

C H C H 3

CH 3

CH CH3

CH31

CH4

CH CH3

S CH3 -(methylthio) hexane

The parentheses in the name of the sulfide are usedto indicate

that thio is associatedwith methylratherthanwith hexane.


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HeterocyclicNomenclature

A number of important ethers

and sulfides contain an oxygen

or sulfur atom within a ring.

Cyclic compounds with rings

that contain more than one type

of atom are called heterocyclic

compounds.


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O

CH2CH2

ethylene

oxide

CH2 CH2

ethylene

O

CH2CHPh

styrene oxide

CH CH2Ph

styrene


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The IUPAC for tetrahydrofuran,

oxolane, is not commonly used

except in indexes such as

Chemical AbstractO

fura

O

ra r furar THF

S

p


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Oxirane is the parent compound

of a special class of heterocyclic

ethers, called epoxides,that

contain three membered-rings.

A few epoxides are named

traditionally as oxides of the

corresponding alkenes:


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O

O

1 , 4 - d o x n e

o r s m yd o x n e

O

o x r n e

o r

e h y e n eo x d e


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However, most epoxides are

named substitutively as

derivatives of oxirane. The

atoms of the epoxide ring are

numbered consecutively with

the oxygen receiving the

number 1 regardless of thesubstituentpresent.


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O1

CH3

CH22

CH2 CH3

2-ethyl i e


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Properties OfAlcohols,Phenols

And Ethers: Hydrogen Bonding

Alcohols, phenols, and etherscan be thought of as organicderivatives of water in whichone or both of the hydrogenshave been replaced by organicparts: HOH becomes ROH or ROR.


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And Ethers: Hydrogen Bonding

Thus all three compounds havenearly the same geometry aswater.

Alcohols have higher boilingpoints than alkanes orhaloalkenes of similar molecular

weight.


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And Ethers:Acidity

Alcohols and phenols, likewater, are both weakly basicand weakly acidic.

As weak acids, alcohols andphenols dissociate to a slightextent in dilute aqueous solution

by donating a proton to water,generating H2O and alkoxideion (RO-) or a phenoxide ion(ArO-).


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Alcohols

Alcohols react with alkali metals

just as water does to yield metal

alkoxides that are themselves

strong bases.


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Methanol

Or methyl alcohol, CH3OH, is

produced commercially from

either carbon monoxide or

carbon dioxide.

It is a colorless liquid, which

boils at 650C

Smells and tastes like ethylalcohol


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Methanol

Is poisonous- breathing the

vapor or drinking the liquid may

cause blindness or death.

Is used in the manufacture of

formaldehyde and other organic

products; as solvent for resins,gums and shellac


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Ethanol

C2H5OH

Called ethyl alcohol, grain

alcohol is the most important

alcohols.

prepared by fermentation of

starch, cellulose, and various

sugars


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Ethanol

Large quantities of ethanol are

synthesized from ethylene and

acetylene

Is a colorless liquid with a

characteristic and somewhat

pleasant odor

It is miscible with water in allproportions


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Ethanol

Boiling point of pure alcohol is

78.370C

It is the least toxic of all the

alcohols and is found in all

alcoholic beverages


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Ethanol

Used as a solvent in tinctures,

essences, and extracts

Preparation of iodoform, ether,

dyes, perfumes, and collodion

Solvent in the lacquer industry

and as motor fuel

Used as additive in some

brands of unleaded gasoline.


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APPLICATION

Ethanol is classified for medical

purposes as a depressant as a

central nervous system (CNS)

depressant.

Increase excitability and

increase in social behavior, but

this results from depression ofinhibition rather than from

stimulation


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APPLICATION

At a blood alcohol concentration

of 0.1% to 0.3%, motor

coordination is affected,

accompanied by loss of balance, slurred speech and

amnesia.


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Application

When blood alcohol

concentration rises to 0.3% to

0.4%,nausea and loss of

consciousness occur.

At concentrations greater than

0.6%, spontaneous respiration

and cardiovascular regulationare affected, ultimately leading

to death.


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Application

The passage of ethanol through

the body begins with its

absorption in the stomach and

small intestines, followed byrapid distribution to all body

fluids and organs.


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Application

In the pituary gland, ethanol

inhibit the production of

hormone that regulates urine

flow, causing increased urineproduction and dehydration.


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Application

In the stomach ethanol, ethanol

stimulates production of acid.

Throughout the body, ethanol

causes blood vessels to dilate,

resulting in flushing of the skin

and a sensation of warmth as

blood moves into capillariesbeneath the surface.


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Application

The result is not warming of the

body, but an increased loss of

heat at the surface.


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Phenols

Aromatic counterparts of alcohol.

The word phenol is used both as

the name of a specific substance

(hydroxyl-benzene) and as the

family name for all hydroxyl-

substituted aromatic compounds.

Phenols are named with phenolused as the parent name rather

than benzene.


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Phenols

Phenols have higher boilingpoints than aromatichydrocarbons.

Phenol itself, for example, boilsat 182oC, whereas toluene boilsat 110.6oC.

Alcohols and phenols haveunusually high boiling pointsbecause, like water, they fromhydrogen bonds in the liquid

state.


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Phenols

Phenols are about a milliontimes more acidic than alcohols.

In fact, some nitro-substituted

phenols approach or surpassthe acidity of carboxylic acids.

One practical consequence ofthis acidity is that phenols aresoluble in dilute aqueousNaOH, but alcohols are not.


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Ethers

Simple ethers that contain no

other functional groups are

named by identifying the two

organic groups and adding theword ether.


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Ethers

If more than one ether linkage is

present, or if other functional

groups are present, the ether

part is named as alkoxysubstituent on the parent

compound.


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Ethers

Ethers, because they lack

hydorxyl groups, cant form

hydrogen bonds and therefore

have lower boiling points.

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Alcohols and Thiols