Describe the structural Describe the structural formulae and reactions formulae and reactions

of compounds of compounds containing selected containing selected functional groupsfunctional groups

4 credits4 credits

• HaloalkaneHaloalkane

• AlcoholAlcohol

• AlkeneAlkene

• AlkyneAlkyne

• EsterEster

• Carboxylic acidCarboxylic acid

Selected organic functional groups are Selected organic functional groups are limited to:limited to:

Compounds are limited to:Compounds are limited to:

Those containing no more than 8 Those containing no more than 8 carbons. Larger organic molecules may carbons. Larger organic molecules may be used in Qs linking structure & be used in Qs linking structure & reactivity.reactivity.

Acid Acid reactions of reactions of carboxylic carboxylic

acidacid

DistinguishinDistinguishing testsg tests

Structural Structural and and

geometric geometric isomersisomers

Knowledge Knowledge of primary, of primary, secondary secondary & tertiary & tertiary alcohols & alcohols &

haloalkaneshaloalkanes

Naming Naming compouncompoun

dsds

ClCl22

HH22O/HO/H++ & HCl & HCl identify identify major & major & minor minor

productsproducts

BrBr22

MnOMnO44-- Oxidation of Oxidation of

primary primary alcohols to alcohols to carboxylic carboxylic

acidacid

polymerisatipolymerisationon

HH22/Pt/Pt

HalogenatioHalogenation of alkanesn of alkanes

Elimination Elimination of water of water

from alcoholfrom alcohol

Organic ChemistryOrganic ChemistryReactions of Reactions of

alkenesalkenes

Formation & Formation & hydrolysis of hydrolysis of esters e.g. esters e.g.

triglyceridestriglycerides

Fats, oils and Fats, oils and soapssoaps•Triglyceride is a fat that contains 3 ester Triglyceride is a fat that contains 3 ester

linkslinks

•Made from 3, long-chain carboxylic acids Made from 3, long-chain carboxylic acids + glycerol (triol)+ glycerol (triol)

•In the esterfication reaction, 3HIn the esterfication reaction, 3H220 is 0 is formed (OH from acid + H from glycerol)formed (OH from acid + H from glycerol)

Beware; Beware; they can they can change change

the the orientatioorientatio

nn

Divide Divide between C between C and O, add and O, add Hs to form Hs to form

triol and OHs triol and OHs to form acidto form acid

Fats, oils and Fats, oils and soapssoapsLike all esters, triglycerides undergo Like all esters, triglycerides undergo

hydrolysis. This reaction can be catalysed hydrolysis. This reaction can be catalysed by either acid or base.by either acid or base.

1.1.With acidWith acid

An acid catalyst is used (not conc. acid) to An acid catalyst is used (not conc. acid) to form glycerol (triol) and carboxylic acid form glycerol (triol) and carboxylic acid again:again:

2.With alkali (OH2.With alkali (OH--))

If NaOH is used, it reacts with the If NaOH is used, it reacts with the carboxylic acid to form a sodium salt and carboxylic acid to form a sodium salt and glycerol. The sodium salt in this case is glycerol. The sodium salt in this case is called ‘soap’ and the reaction is called called ‘soap’ and the reaction is called ‘saponification’‘saponification’

Acid conditions: glycerol and palmitic Acid conditions: glycerol and palmitic acid formed.acid formed.

Alkali conditions: glycerol and the Alkali conditions: glycerol and the sodium salt of palmitic acid formedsodium salt of palmitic acid formed

Notice Notice there are there are

3 diff. 3 diff. acidsacids

In basic conditions: glycerol would In basic conditions: glycerol would still form but instead of the acid a still form but instead of the acid a sodium salt would form.sodium salt would form.

Na

PolymerisatiPolymerisationon•A polymer is a large molecule made of A polymer is a large molecule made of

small molecules called monomerssmall molecules called monomers

•In addition polymerisation, nothing else In addition polymerisation, nothing else is madeis made

•All monomers are alkenesAll monomers are alkenes

•Could be asked to draw monomers from Could be asked to draw monomers from polymers or vice versapolymers or vice versa

OH

CH=CH2

Isolate 2 Isolate 2 carbons to form carbons to form the basis of the the basis of the

alkene alkene monomermonomer

Break the Break the double bond, double bond, attach to next attach to next

monomermonomer

Isolate 2 Isolate 2 carbons, carbons,

straighten them straighten them and put the and put the

double bond indouble bond in

Naming Naming compoundscompoundsLearn functional groups and endings!Learn functional groups and endings!

GroupGroup StructureStructure Name endingName ending

AlkaneAlkane C-CC-C -ane-ane

AlkeneAlkene C=CC=C -ene-ene

AlkyneAlkyne C=CC=C -yne-yne

AlcoholAlcohol -OH-OH -anol -anol

HaloalkanHaloalkanee

e.g. –Cle.g. –Cl e.g Chloro-e.g Chloro-aneane

Carboxylic Carboxylic acidacid

OHOH

C=OC=O-anoic acid-anoic acid

EsterEster -C=O-C=O

OO-thyl-anoate-thyl-anoate

1-1-chloropropchloropropaneanemethylpropmethylpropanoateanoate

Crocodiles! Crocodiles! What is eaten What is eaten first is named first is named

first!first!Numbering Numbering

begins at ene begins at ene endend

-anoic grp is -anoic grp is always on always on carbon 1carbon 1

Structural Structural isomersisomersSame number of atoms in a different Same number of atoms in a different

arrangementarrangement

Geometric Geometric isomersisomers• Different arrangements of atoms in Different arrangements of atoms in

spacespace

• Cis (same side) & trans (across) Cis (same side) & trans (across)

• Due to double bond being unable to Due to double bond being unable to rotaterotate

• Can have different properties e.g. Can have different properties e.g. polarity & boiling pointpolarity & boiling point

methylpromethylpropenepene

cyclobucyclobutanetane

Don’t need to give Don’t need to give number placing for number placing for methyl and ene. methyl and ene.

They can be They can be nowhere else!nowhere else!

But-1-But-1-eneene

But-2-But-2-eneene

Cannot Cannot form cis & form cis & trans trans because the because the groups on groups on each C are each C are not not differentdifferent

Can form cis & trans Can form cis & trans because the groups because the groups on each C are on each C are different and the different and the double bond doesn’t double bond doesn’t allow rotationallow rotation

Base the drawing Base the drawing around the double around the double

bond to examine the bond to examine the groupsgroups

Remember this! It’s Remember this! It’s the stock answer for the stock answer for

explaining explaining geometric isomersgeometric isomers

Reactions of Reactions of alkenesalkenes

Reaction Reaction typetype

ReagentReagent ConditioConditionsns

ProductProduct

HydrogenatiHydrogenationon

HydrogenHydrogen Pt/HPt/H22 or or Ni/HNi/H22

AlkaneAlkane

HydrationHydration WaterWater HH++/H/H2200 AlcoholAlcohol

HalogenatioHalogenationn

HalogenHalogen BrBr22 or Cl or Cl22 HaloalkaHaloalkanene

HalogenatioHalogenationn

Hydrogen Hydrogen halidehalide

HCl or HCl or HBrHBr

HaloalkaHaloalkanene

OxidationOxidation Potassium Potassium permanganpermanganateate

HH++/MnO/MnO44-- DiolDiol

All types of All types of addition addition reactionsreactions

Watch out for Watch out for Markovnikov’s! Markovnikov’s! Asymmetrical Asymmetrical

alkene = 2 alkene = 2 productsproducts

Watch out for Watch out for Markovnikov’s! Markovnikov’s! Asymmetrical Asymmetrical

alkene = 2 alkene = 2 productsproducts

Primary, secondary & Primary, secondary & tertiarytertiary• Classifications in alcohols and Classifications in alcohols and

haloalkaneshaloalkanes

• Look at the Carbon the alcohol/halogen Look at the Carbon the alcohol/halogen is attached to. Is this attached to 1, 2 or 3 is attached to. Is this attached to 1, 2 or 3 carbons?carbons?

• Form straight line (!), T-shape or crossForm straight line (!), T-shape or cross

primaprimaryry

seconsecondarydary

primaprimaryry

tertiartertiaryy

Reactions of Reactions of alcoholsalcohols• Elimination of water (dehydration):Elimination of water (dehydration):

alcohol alcohol Alkene + water Alkene + water

• Oxidation of 1Oxidation of 1° alcohol:° alcohol:

11° alcohol ° alcohol (aldehyde) (aldehyde) Carboxylic Carboxylic acidacid

Can use HCan use H++/MnO/MnO44- - as oxidising agent instead. Purple to as oxidising agent instead. Purple to

colourlesscolourless

• Esterfication:Esterfication:

alcohol + Carboxylic acid alcohol + Carboxylic acid ester ester

Conc. HConc. H22SOSO44

HH++/Cr/Cr22OO772-2-

Dichromate turns from Dichromate turns from orange to greenorange to green

Conc. HConc. H22SOSO44

This is a This is a dehydration dehydration

reaction reaction (elimination)(elimination)

Alcohol + acid…Alcohol + acid…

Oxidation of a Oxidation of a primary primary alcohol…alcohol…

Potassium permanganate will Potassium permanganate will turn from purple to colourlessturn from purple to colourless

Reactions of carboxylic Reactions of carboxylic acidsacids• Normal acid reaction e.g. fizzing with Normal acid reaction e.g. fizzing with

metal metal H H22 & fizzing with carbonates & fizzing with carbonates COCO2 2 & litmus turning red& litmus turning red

• Form metal salts involving the organic Form metal salts involving the organic acid e.g. sodium methanoateacid e.g. sodium methanoate

• Form esters when reacted with alcoholsForm esters when reacted with alcohols

Distinguishing testsDistinguishing testsGroupGroup DamDam

p p litmulitmuss

HH++/Cr/Cr22OO772-2- Sodium Sodium

carbonacarbonate sol.te sol.

SmellSmell Warm Warm HH++/MnO/MnO44

--

BrominBromine e waterwater

AlcoholAlcohol 11° turns ° turns from from orange to orange to greengreen

Forms 1 Forms 1 layerlayer

11° turns ° turns from from purple purple to to colourlecolourlessss

Stays Stays orangorangee

HaloalkaHaloalkanene

Stays Stays orangeorange

Forms 2 Forms 2 layerlayer

Stays Stays purplepurple

Stays Stays orangorangee

Carbox. Carbox. AcidAcid

TurnTurns reds red

Stays Stays orangeorange

Forms 1 Forms 1 layer layer that that fizzesfizzes

pungepungentnt

Stays Stays purplepurple

Stays Stays orangorangee

EsterEster Stays Stays orangeorange

Forms 2 Forms 2 layerslayers

fruityfruity Stays Stays purplepurple

Stays Stays orangorangee

AlkaneAlkane Stays Stays orangeorange

Forms 2 Forms 2 layerslayers

Stays Stays purplepurple

Slowly Slowly decolodecolour w/ ur w/ uVuV

AlkeneAlkene Stays Stays orangeorange

Forms 2 Forms 2 layerslayers

strongstrong Purple Purple to to colourlecolourlessss

Quickly Quickly decolodecolourur

Acidified potassium Acidified potassium dichromate dichromate (H(H++/Cr/Cr22OO77

2-2-))Propan-1-ol will turn acidified Propan-1-ol will turn acidified potassium dichromate from orange potassium dichromate from orange to green. Propanoic acid will remain to green. Propanoic acid will remain orange.orange.

There are other There are other possible possible

answers, see answers, see how many you how many you can come up can come up

with!with!

hexhexaneane

hex-1-hex-1-eneeneDecolourises Decolourises

bromine slowly bromine slowly with UV lightwith UV light

Decolourises Decolourises bromine quicklybromine quickly

Saturated so Saturated so undergoes a undergoes a substitution substitution reactionreaction

unsaturated so unsaturated so undergoes an undergoes an addition reactionaddition reactionForms 1-Forms 1-

bromohexanebromohexaneForms 1,2-Forms 1,2-dibromohexanedibromohexaneCHCH33CHCH22CHCH22CHCH22CHCH22CHCH3 3

+ Br+ Br22

CHCH22BrCHBrCH22CHCH22CHCH22CHCH22CHCH

33 + HBr + HBr

CHCH22CHCHCHCH22CHCH22CHCH22CHCH3 3 + + BrBr22

CHCH22BrCBrCHBrCBrCH22CHCH22CHCH22CHCH

33 + HBr + HBr

Adding water Adding water to an to an

asymmetric asymmetric alkene…but alkene…but

which product which product goes where?goes where?

End product End product = ester. = ester.

Reagent = Reagent = alcohol. So C alcohol. So C

must be…must be…

Propanoic Propanoic acidacid

So B must be So B must be a primary a primary

alcohol and alcohol and reagent D reagent D

must be an must be an oxidantoxidant

Propan-1-Propan-1-olol HH++/Cr/Cr22OO77

2-2-Propan-2-Propan-2-olol

To form a To form a sodium salt sodium salt of an ester…of an ester…

NaOHNaOH