1 unit 4 + 5 (2008- syllabus). paper details 4u4 exam 1h 40m. 3 sections. (90 mks??). section a,b...

1

Unit 4 + 5 (2008- syllabus)

Paper details

• U44 Exam 1h 40m. 3 sections. (90 mks??). Section A,B & C

• A = multiple choice (objective Q's)

• B = Short answers & extended Q's inc. analysis and evaluation of practical work

• C = Data questions and use of data

Paper details• U5 Exam 1h 40m. 90 marks. Section A,B & C

• A = multiple choice (objective Q's)• B = Short answers & extended Q's inc. analysis and evaluation of

practical work• C = Questions requiring extended answers. 'Senarios' may be given

and students expected to answer Q's based on the chemistry presented. “Contemporary context questions”.“Contemporary context questions”.

• Sections B & C will be where a students can show their full ability. Knowledge from previous units required.

• QWC considered. Data book can be used.

Unit 2.10(Organic I)

Reaction summary

Followed by Unit 4.8 Further organic chemistry (Organic II)

Mike Allan Hamzah. INTEC 2010. My information here is free of all restrictions

Recall of function groups…Recall of function groups…Functional groups.• Atoms or sequences of atoms causing

deviations in electron density to that of its hydrocarbon equivalent. E.g ethanol & ethane

(C=C, -X, -OH, -COOH <<< Unit 2.10)

CMgBr, -COOH, COOR, CMgBr, -COOH, COOR, CHO, COCHO, CO, -NH, -NH22,,

-NHR, -NR-NHR, -NR22, -COX, CONR, -COX, CONR22, CN,, CN,

Ether: REther: R33C-O-CRC-O-CR33(R=H or carbon)(R=H or carbon)

Unit 2.10 summary

Alkanes

CO2 + H2O

As fuelsAs fuels

Halogenoalkanes

FunctionalizationFunctionalizationvia halogen radicalsvia halogen radicals(need X(need X22 and U.V.) and U.V.)

PyrolysisPyrolysis(thermal cracking)(thermal cracking)not on syallabusnot on syallabus

Alkanesof differenttypes andalkenes

Alkenes

KMnOKMnO44(aq)(aq)

& OH& OH--(aq)(aq)

C=C

A diolA diol

C-C

HO OH

polymerizationpolymerization

C-C-C

poly(ethene) - PEpoly(ethene) - PEpoly(propene) – PPpoly(propene) – PPpoly(vinylchloride) - PVCpoly(vinylchloride) - PVCpoly(tetrafluoroethene) – PTFEpoly(tetrafluoroethene) – PTFE

HydrogenationHydrogenationHH22(g) + (g) +

Rayney nickelRayney nickel

AlkenesAlkenes

ADDITION REACTIONS !!!ADDITION REACTIONS !!!cis-cis- and and trans-trans- isomers possible isomers possible

due to restricted C=C bonddue to restricted C=C bond

PolymersPolymers

H X

HydrogenHydrogenhalogenationhalogenation

Use MarkovnikovUse MarkovnikovIf If unsymmetricalunsymmetrical

HalogenationHalogenation(X(X22))

C-C X X

C-X

Halogenoalkanes

C-NH2

KKCNCNRefluxReflux

under heatunder heat(ethanol solvent)(ethanol solvent)

Nucleophilic substitutionNucleophilic substitution

andand

Elimination reactionsElimination reactions

KOH(ethanolic)KOH(ethanolic)Reflux under heatReflux under heat

(dehydrohalogenation)(dehydrohalogenation)Elimination!Elimination!

C=C

C chainC chainextended !!!extended !!!

PolysubstitutionPolysubstitutionpossible. To 2possible. To 200 and 3 and 300 amine amine

C-C≡N

KOH(aq)KOH(aq)Reflux under heatReflux under heat

C-OH

Displaced XDisplaced X--

This can thereforeThis can thereforebe uses to testbe uses to test

for the (halogen)type of R-Xfor the (halogen)type of R-X

After reflux add HNOAfter reflux add HNO33 (aq) (aq)

THEN Ag(NO3)(aq)THEN Ag(NO3)(aq)

Excess c.NHExcess c.NH33

Reflux under heatReflux under heat

C-OH

Alcohols

NaX and c.HNaX and c.H22SOSO44

Reflux under heatReflux under heat

HalogenoalkaneHalogenoalkane(alkyl halide)(alkyl halide)

C-X

oxidationoxidation

C-O-Na+

KK22CrCr22OO77 (aq) + H (aq) + H22SOSO44(aq)(aq)

Distill for aldehydeDistill for aldehydeReflux for carbox. acid.Reflux for carbox. acid.

PClPCl55 / PCl / PCl33 / SOCl / SOCl22

2P + 3Br2P + 3Br22

2P + 3I2P + 3I22

Nucleophilic substitution, Nucleophilic substitution,

elimination, andelimination, and

oxidation reactionsoxidation reactions

Na(s)Na(s)c. Hc. H22SOSO44

170 170oo

(elimination)(elimination)

C=C sodium alkoxidesodium alkoxide

C

AldehydesAldehydes&&

ketonesketones

COOH

O

RR’

Carbox. acidsCarbox. acids

If aldehydeIf aldehyde

oxidationoxidationAlAl22OO33(s) 300(s) 300ooC C

andandPP44OO1010

can alsocan alsobe usedbe used

N.B. Initial alcoholN.B. Initial alcoholmust be drymust be dry

4.8 Further 4.8 Further OrganicOrganic

4.8 Further Organic4.8 Further Organic

enantiomers

4.8 Further Organic4.8 Further Organic4.8.1 Chirality4.8.1 Chirality a) recall the meaning of structural and a) recall the meaning of structural and E-ZE-Z isomerism (geometric/cis-trans isomerism) isomerism (geometric/cis-trans isomerism)

Zis is cis

BA

D G

E = trans

• Identify largest group by atomic number Identify largest group by atomic number (or mass) on one side of db (e.g A & B)(or mass) on one side of db (e.g A & B)

• Do the same on other sideDo the same on other side (D and G) (D and G)

• Atoms of greatest at# on same side of Atoms of greatest at# on same side of the db, then compound = the db, then compound = ZZ isomer. isomer.

4.8.1 Chirality4.8.1 Chirality b) demonstrate an understanding of the existence of optical b) demonstrate an understanding of the existence of optical isomerism resulting from chiral centre(s) in a molecule with isomerism resulting from chiral centre(s) in a molecule with asymmetricasymmetric carbon carbon atom(s) and understand optical isomers as object and non-superimposable atom(s) and understand optical isomers as object and non-superimposable mirror imagesmirror images

• Chiral = Chiral = nonnon superimposable on its mirror superimposable on its mirror image. A pair of enantiomers is the result.image. A pair of enantiomers is the result.

• Asymetric = no element of symmetry Asymetric = no element of symmetry (reflection, rotation, reflection & inversion)(reflection, rotation, reflection & inversion)

http://astrobiology.berkeley.edu/Mars101/definitions.htm

http://chemed.chem.purdue.edu/genchem/topicreview/bp/1organic/chirality.html

• A substance is optically active if it rotates the plane of polarisation of monochromatic plane polarised light (ppl). [ poppop of monomono pplppl ] ]

• One enantiomer will rotate light by some angle, say +x degrees, but the other enantiomer will rotate the plane of monochromatic ppl by the same magnitude but in the opposite direction, say –x degrees.

4.8.1 Chirality4.8.1 Chirality c) recall optical activity as the ability of a single optical isomer to c) recall optical activity as the ability of a single optical isomer to rotate the plane of polarization of plane-polarized monochromatic light in rotate the plane of polarization of plane-polarized monochromatic light in molecules containing a single chiral centre and understand the nature of a molecules containing a single chiral centre and understand the nature of a racemic mixtureracemic mixture

Huh?...Huh?...

http://www.denhartog-scientific.nl/Producten/Polarimeter/Polarisg[1].jpg

http://andromeda.rutgers.edu/~huskey/images/polarimeter.jpg

Huh?...Huh?...

• One sourceOne source of chirality (the property of being of chirality (the property of being chiral) is in aliphatics with chiral) is in aliphatics with 4 different gps on 4 different gps on the same Cthe same C atom… but 4 diff gps isn’t the atom… but 4 diff gps isn’t the only way u can get chiral molecules. E.g. only way u can get chiral molecules. E.g. DNA helix, spirenes…DNA helix, spirenes…

http://chemistry.umeche.maine.edu/CHY251/Chirality.gif

• Different optical isomers can have radically different BIOLOGICAL properties. Phys props (other than optical rotation) usually the same.

http://waynesword.palomar.edu/images/limonene.jpg

• Thalidomide – enantiomers showing different biological effects

http://en.wikipedia.org/wiki/File:Thalidomide-structures.png

4.8.1 Chirality4.8.1 Chirality d) use data on optical activity of reactants and d) use data on optical activity of reactants and products as evidence for proposed mechanisms, as in SN2 and products as evidence for proposed mechanisms, as in SN2 and SN1 and addition to carbonyl compounds.SN1 and addition to carbonyl compounds.

• SN2 (animation page) (OR video1 vid2) rxns involve inversion of centre of chiraity (stereocentre). Product is optically active – will cause plane of polarisation of monochromatic ppl to rotate. Transition state.Transition state.

SSN2N2

“Stereochemistry at a glance By Jason Eames, Josephine Peach. Google books P42

4.8.1 Chirality4.8.1 Chirality d) use data on optical activity of reactants and d) use data on optical activity of reactants and products as evidence for proposed mechanisms, as in SN2 and products as evidence for proposed mechanisms, as in SN2 and SN1 and addition to carbonyl compounds.SN1 and addition to carbonyl compounds.

• SN1 (animation page) rxns have the substrate give racemic mixtures (mixtures of both enantiomer products). Product mixture is optically inactive – no effect of plane of polarisation of monochromatic ppl. Carbocation intermediate (may rearrange).Carbocation intermediate (may rearrange).

“Mechanisms in organic reactions” By Richard A. Jackson.Google books P104

SSN1N1

• AldehydesAldehydes RCHO R can be H or hydrocarbon. Methanal, ethanal, propoanal… benzaldehyde

• KetonesKetones RCOR’ R cannot be H, must be hydrocarbon (no methanone or ethanone) propanone(acetone), cyclohexanone

4.8.2 4.8.2 Carbonyl compoundsCarbonyl compounds a) a) give examples of give examples of molecules that contain the aldehyde or ketone functional molecules that contain the aldehyde or ketone functional groupgroup

Ald’s and ket’s with larger more complicated perfumes and flavourings. VolatilityVolatility is important.

4.8.2 4.8.2 Carbonyl compoundsCarbonyl compounds b) e b) explain the physical xplain the physical properties of aldehydes and ketones relating this to the properties of aldehydes and ketones relating this to the lack of hydrogen bonding between molecules and their lack of hydrogen bonding between molecules and their solubility in water in terms of hydrogen bonding with the solubility in water in terms of hydrogen bonding with the waterwater

MethanalMethanal(polar)(polar)

gasgas

Propanone Propanone (polar)(polar)

Volatile Volatile liquidliquid

Can H bond with water.!! & both polar, so soluble in Can H bond with water.!! & both polar, so soluble in water up to a few C’s long.water up to a few C’s long.

Electron density maps Red = Electron density maps Red = --

Ethanal Ethanal (not shown)(not shown) is the first aldehyde to be liquid at RTP. is the first aldehyde to be liquid at RTP.

Bpt > corresponding alkanes, but < than corresponding alcohols.Bpt > corresponding alkanes, but < than corresponding alcohols.

http://www.mhhe.com/physsci/chemistry/carey/student/olc/graphics/carey04oc/ch17/figures/acetoneepot2.jpg

http://www.mhhe.com/physsci/chemistry/carey/student/olc/graphics/carey04oc/ch17/figures/methanalepot.jpg

Aldehydes ‘n KetonesAldehydes ‘n Ketones

..O

C

C

:

C

..O

H

C

:

C

ketonealdehyde

Aldehydes tend to be more reactive than ketones because, sterically, of the lack of extra alkyl chain

as present in ketones. Also the alkyl chain, by inductive effect (+I), releases e- density to carbonyl and lowering charge on carbonyl, delocalizing the

charge over the nearby area.

4.8.2 4.8.2 Carbonyl compoundsCarbonyl compounds c) describe and carry out, where appropriate, the reactions of carbonyl compounds. This will be limited to:

i. oxidation with Fehling’s or Benedict’s solution, Tollens’ reagent and acidified dichromate(VI) ions

ii. reduction with lithium tetrahydridoaluminate (lithium aluminium hydride) in dry ether


1O Alcohol

2O Alcohol

3O Alcohol

aldehyde

carboxylicacid

ketone

LiAlHLiAlH44 in dry etherin dry ether

(esters can be reduced too!!!)(esters can be reduced too!!!)

OXIDATIONOXIDATION

ReductionReduction

AlcoholsAlcohols CarbonylsCarbonyls Carbox. acidsCarbox. acids

NaBHNaBH44 (can be aq too!)(can be aq too!)

Aldehydes Aldehydes can

undergo oxidn and

Redn

Ketones Ketones undergo

Redn

Acts as if a source of HActs as if a source of H-- (a (a nucleophile)nucleophile)

Aldehydes can be oxidised by a number of compounds, some are employed as a TEST to TEST to discriminate aldehydes from ketonesdiscriminate aldehydes from ketones

1) Fehlings solution (Cu2+ complex)

2) Tollens reagent / test (ammoniacal silver nitrate – [Ag(NH3)2]+ complex

3) Acidified K2Cr2O7(aq) or acidified KMnO4(aq)

OXIDATIONOXIDATIONAldehydes ‘n KetonesAldehydes ‘n Ketones

Fehlings A is a solution of CuSO4(aq)

Fehlings B sodium tartrate solutionand NaOH

Both solutions mixed together toform the chelated Cu2+ after intitial Cu(OH)2 ppte seenby the bidentate tartrate ions surrounding the Cu2+

- deprotonation of hexaaqua ligand does not occur – tartrate is a stronger ligand.

Cu2+ only reacts in one way and that is to gain electrons! It causes the loss of e- from a different species is an O.A.


On heating (to inc. rate of rxn), a red Cu(I) oxide precipitate forms

1) Fehlings sol1) Fehlings solnn

AgNO3(aq) + few drops of NaOH(aq) Ag(OH)(s)

Add NH3(aq) until black ppte just dissolves.[Ag(NH3)2]+ forms {counter ion = - OH}


2) Tollens reagent2) Tollens reagent

Heat with aldehyde andAg(s) is deposited

on walls of glass container.A silver mirror is formed.

If solution or container is dirty grey / black Ag2O(s) ppte can form.

INTERVALINTERVAL

• In rxn with of cyanide anionscyanide anions with halogenoalkaneshalogenoalkanes,(nucleophilic substitution), X substitutes (leaves) with :C≡N, so simply use KCN in a mix of ethanol and water solvent and refluxing under heat.

• However in the addition reactions with carbonyls, nucleophilic additionnucleophilic addition takes place. HCN(a gas) adds rapdily to carbonyls,

• e.g ethanal + HCN(g) 2-hydroxypropanenitrile. CH3 CH(OH)-CN

• HCN made by adding dil H2SO4 with KCN(in excess to allow sufficient –’ve CN ions

4.8.2 4.8.2 Carbonyl compoundsCarbonyl compounds c) describe and carry out, where appropriate, the reactions of carbonyl compounds. This will be limited to:

iii. nucleophilic addition of HCN in the presence of KCN, using curly arrows, relevant lone pairs, dipoles and evidence of optical activity to show the mechanism

-

--


HCN H+ + -:CN⇁↼

• Alkaline conditions don’t allow for the protonation of the carbonyl gp but do give high (:CN)- concentration. A compromise of about pH 5 gives the best results. Animation page.


O

H

CH3C :CN

-O:

H

CH3C CN

-H+

OH

H

CH3C CN

A CYANOHYDRIN (an -hydroxy nitrile) is produced.These compounds are useful for (further) synthesis.

Q: State a property of cyanohydrins…Q: State a property of cyanohydrins…

• Alkaline conditions don’t allow for the protonation of the carbonyl gp but do give high (:CN)- concentration. A compromise of about pH 5 gives the best results. Animation page


O

H

CH3C :CN

-O:

H

CH3C CN

-H+

OH

H

CH3C CN

A CYANOHYDRIN (an -hydroxy nitrile) is produced.These compounds are useful for (further) synthesis.

(or H-CN)

(Generates H+)

*

Q: State a property of cyanohydrins…Q: State a property of cyanohydrins…


Nitriles (CYANOHYDRINs) can undergo hydrolysis reactions

OH

H

CH3C CN

OH

H

CH3C

O

OH

C

Dilute acid(H2SO4)

Heat underreflux

An hydroxyacid

Dilute NaOH can also be used. Heat under reflux but like base

hydrolysis of esters, the anion of the carboxylic acid will form!!!

Each hydrazine reacts with carbonyls to form a hydrazone. Hydrazine itself is very toxic and so is no

longer used. The dinitrophenyl version is employed instead.

Aldehydes ‘n KetonesAldehydes ‘n Ketones TESTTEST

SpecificSpecific for carbonyl…!!! for carbonyl…!!!

..N N

H

H

H

O2N

NO2

..

2,4-dinitrophenylhydrazine (2,4-dnp)

N N

H

H

H

H

....

hydrazine

The 2,4-dnp test

This lone pair is the active one and attacks the carbonyl carbon

..N N

H

H

H

O2N

NO2

..

N N

H

H

O2N

NO2

..

N N

H

H

H

O2N

NO2

..+

H

Aldehydes ‘n KetonesAldehydes ‘n Ketones TESTTEST

The 2,4-dnp test

O

H

CH3C

(1)(2)

lp on N actsas a nucleophile

..O

HC

:

H3C

:-N & O undergo proton

exchange

..O

HC

:

H3C

N N

H

O2N

NO2

C

CH3

H

..ck

A

hyd

razo

ne

ckorange Yellow

ppte

(3)

(4)

(5)

(6)

(7)

++

http://www.chem.ucalgary.ca/courses/351/Carey/Ch17/ch17-3-3-2.html

48 propanal 14856 acetone 12663 2-methylpropanal 187(183)75 butanal 12380 2-butanone 11791 3-methylbutanal 12392 2-methylbutanal 120100 2-pentanone 143102 3-pentanone 156103 pentanal 107(98)115 4-methyl-2-pentanone 95128 5-hexen-2-one 1081294-methyl-3-penten-2-one 205131 cyclopentanone 146131hexanal 104(107)145 4-heptanone 75145 5-methyl-2-hexanone 95

Bp ofStartingCarbonylUnknown

mp of2,4-DNPDerivative

131 hexanal 104(107)145 4-heptanone 75145 5-methyl-2-hexanone 95146 2-heptanone 89147 3-heptanone 81153 heptanal 108156 cyclohexanone 162169 3-methylcyclohexanone 155173 2-octanone 58179 benzaldehyde (PhCHO) 237200 o-methylbenzaldehyde 194204 p-methylbenzaldehyde 34202 ethanoylbenzene 244216 1-phenyl-2-propanone 156217 (2-methylpropanoyl)benzene 163218 propanoylbenzene 191226 p-methylacetophenone 258232 butanoylbenzene 191235 4-phenyl-2-butanone 127248 p-methoxybenzaldehyde 253

mp of2,4-DNPDerivative

Bp ofStartingCarbonylUnknown

SomeSome aldehydes, aldehydes, some some ketones and ketones and somesome alcohols… alcohols…

Specific reaction…

Triiodomethane rxn

(iodoform precipitation reaction)DOES NOT:a) Identify carbonyls from alcohols

b) Identify aldehydes from ketones

Triiodomethane rxn(iodoform precipitation reaction)

So what does it do?

a) Tests for methyl carbonylsmethyl carbonyls

b) Tests for methyl alcoholswhich can be oxidised to methyl carbonyls.

Note: cannot be tertiary alcohols in that case!

C

H

H

H

CO

Acyl group(abbreviation Ac)

C

H

H

H

C

OH

H


Required reagents:

• I2(aq) + NaOH(aq)

or

• KI(aq) + NaClO(aq)(ClO- is an O.A. and ‘dynamically

converts I- into I2 )

C

H

H

H

CO

Acyl group(abbreviation Ac)

C

H

H

H

C

OH

HAll these alpha H’sget replaced by I


C

I

I

I

CO Forms rapidly

C

I

I

I

H

Triiodomethane (ioodoform), an unpolar SOLID, ends up breaking away.

(appropriate alcohol versions get oxidised to this acyl gp first)

Carboxylate anion on

other fragment

dissolves in soln


The triiodomethane smells like antiseptic or a dry cleaners (dry cleaners used to use trichloromethane – a compound (probably toxic: carconogenic, tetragenic and mutagenic – not that nice really and it’s said to destroy ozone.)

Always better to ID iodoform from the ppte rather than the smell !!!

Test may be problematical – my guess [I2] is too low in the ‘bench’ test solution.

Further Organic revision.Source: http://www.rod.beavon.clara.net/Problem 1.

Compound A, C3H80, gives steamy fumes when reacted with phosphorus pentachloride. On oxidation with acidified potassium dichromate solution A gives B, C3H60. This, with a source of H3C:- nucleophile, gives C upon addition of acid, C4H10O. C does not react with acidified potassium dichromate solution. Treatment of C with excess hot concentrated sulphuric acid gives D, C4H8, which on reaction with hydrogen bromide gives mainly 2-bromo-2-methylpropane. Find the structures of A to D, giving reasons and equations for the reactions which occur.

Further Organic revision.Source: http://www.rod.beavon.clara.net/Problem 2.

Benzene C6H6 and chloromethane CH3Cl react in the presence of aluminium chloride to give A, C7H8. A reacts with chlorine in sunlight to give B, C7H7Cl, which reacts with aqueous sodium hydroxide to give C, C7H8O. Mild oxidation of C gives D, C7H6O, which with 2,4-dinitrophenylhydrazine gives an orange precipitate. Further oxidation of D gives E, C7H6O2, which can also be produced from A by vigorous oxidation with alkaline potassium manganate(VII) solution.

The reaction of B with potassium cyanide under suitable conditions gives F, C8H7N, which in turn can be reduced to G, C8H11N.Identify the substances A to G, giving reasons for your choice and writing equations for the reactions that occur. Write the mechanism for the reaction between benzene and chloromethane. Suggest another series of reactions by means of which you could convert F to G.

4.8.3. Carboxylic acids • a. give some examples of molecules that contain the carboxylic acid

functional group• b. explain the physical properties of carboxylic acids in relation to

their boiling temperatures and solubility due to hydrogen bonding

Palmitic acid C16 H32 O2 benzoic acid C16 H32 O2

R-COOH&

bptCarboxylic acids have much higher boiling points than hydrocarbons, alcohols, ethers, aldehydes, or ketones of similar molecular weight. Even the simplest carboxylic acid, formic acid, boils at 101 °Cformic acid, boils at 101 °C which is considerably higher than the boiling point of ethanol (ethyl alcohol), C2H5OH, which boils at 78.5 °C, although the two have nearly identical molecular weights. The difference is that two molecules of a carboxylic acid form two hydrogen bonds with each other (two alcohol molecules can only form one). Thus, carboxylic acids exist as dimers (pairs of molecules), not only in the liquid state but even to some extent in the gaseous state. Therefore, boiling a carboxylic acid requires the addition of more heat than boiling the corresponding alcohol, because (1) if the dimer persists in the gaseous state, the molecular weight is in effect doubled; and, (2) if the dimer is broken upon boiling, extra energy is required to break the two hydrogen bonds. Carboxylic acids with higher molecular weights are solids at room temperature (e.g., benzoic and palmitic acids). Virtually all salts of carboxylic acids are solids at room temperature, as can be expected for ionic compounds.

http://www.britannica.com/EBchecked/topic/95261/carboxylic-acid/277734/Boiling-point

Name Formula Melting Point (oC) Boiling Point (oC)

formic HCOOH 8 100.5

acetic CH3COOH 16.6 118

propionic CH3CH2COOH -22 141

butyric CH3(CH2)2COOH -6 164

valeric CH3(CH2)3COOH -34 187

caproic CH3(CH2)4COOH -3 205

lauric CH3(CH2)10COOH 44 225

myristic CH3(CH2)12COOH 54 251

palmitic CH3(CH2)14COOH 63 269

stearic CH3(CH2)16COOH 70 287

oleic cis-9-Octadecenoic 16 223

cyclohexanecarboxylic cyclo-C6H11COOH 31 233

phenylacetic C6H5CH2COOH 77 266

benzoic C6H5COOH 122 250

o-toluic o-CH3C6H4COOH 106 259

m-toluic m-CH3C6H4COOH 112 263

p-toluic p-CH3C6H4COOH 180 275

http://wwwchem.csustan.edu/CHEM3022/Table_CbxlcAcid.htm

A look at the COOHA look at the COOHfunctional groupfunctional group

O

O

C

H

Because both functional Because both functional groups are on the groups are on the same same

carboncarbon, each group strongly , each group strongly affects the properties of the affects the properties of the other group, therefore other group, therefore each each

part produces: a unique whole.part produces: a unique whole. So do So do NOTNOT consider the COOH consider the COOH group as showing properties of group as showing properties of

alcohol or of carbonyls.alcohol or of carbonyls.

carbonyl

alcohol

At first sight…At first sight…

c. describe the preparation of carboxylic acids to include oxidation of alcohols and carbonyl compounds and the hydrolysis of nitrilesd. describe and carry out, where appropriate, the reactions of carboxylic acids. This will be limited to:i. reduction with lithium tetrahydridoaluminate (lithium aluminium hydride) in dry ether (ethoxyethane)ii. neutralization to produce salts, eg to determine the amount of citric acid in fruitiii. phosphorus(V) chloride (phosphorus pentachloride) iv. reactions with alcohols in the presence of an acid catalyst, eg the preparation of ethyl ethanoate as a solvent or as pineapple flavouring.

KK22CrCr22OO77 (aq) (aq)

++ HCl (aq) HCl (aq)

Unit 4.8.3 Carboxylic acidsUnit 4.8.3 Carboxylic acids

11oo alcohols alcohols

O

O

C

H

aldehydesaldehydes

KK22CrCr22OO77 (aq) (aq)

++ HCl (aq) HCl (aq)

GrignardsGrignards1)1) COCO22

2)2) HCl (aq)HCl (aq)

Acid halidesAcid halidesHH22O (l)O (l)

EstersEsters

( Inc. polyesters )( Inc. polyesters )

Hydrolysis ofHydrolysis ofamides andamides and

acidic workupacidic workup

PClPCl55

AcidAcidhalideshalides

1O Alcohol

2O Alcohol

3O Alcohol

aldehyde

carboxylicacid

ketone

LiAlHLiAlH44 in dry ether in dry ether

(esters can be reduced too!!!)(esters can be reduced too!!!)

OXIDATIONReductionReduction

AlcoholsAlcohols CarbonylsCarbonyls Carbox. acidsCarbox. acids

NaBHNaBH44 (can be aq too!) (can be aq too!)

Memory aid.Memory aid.AlcoholsAlcohols

and related and related compoundscompounds

Carbox.acids

http://www.mhhe.com/physsci/chemistry/carey/student/olc/graphics/carey04oc/ref/ch19reactioncarboxylicacids.html

Nitriles

http://www.chem.uic.edu/web1/OCOL-II/WIN/CH21/RXNS.HTM

Acidchlorides

http://users.ox.ac.uk/~mwalter/web_05/year1/year1_notes/carbonyl_chemistry/acid_chlorides.shtml

Fatty acids

http://www.hidden-diabetes-cures.com/fats-and-oils.htm

http://www.rsc.org/images/44---feature-fat-structure_tcm18-34671.jpg

http://www.raw-milk-facts.com/images/FatTrio.gif

Margarine

Margarine (?)

• Unsaturated oil + H2(g) -> saturated fat

• Add vitamins, colour…http://www.rsc.org/images/Fig2_pp109_Hargreaves_July09_tcm18-154953.jpg

http://www.quitehealthy.com/nutrition-facts/food-labels/label046131.gif

Soap:

Where you getfatty acids, youcan get esters!

Esters Production of Biodiesel (esters) and base hydrolysis of esters to Make Soap

Transesterification - BoidieselTransesterification - Boidiesel

TransesterificationTransesterification

• Biodiesel.

TransesterificationTransesterification

http://ezbiodiesel.com/News.htm

http://scienceprofonline.googlepages.com/chemistryhelp-organicandinorganic

1 unit 4 + 5 (2008- syllabus). paper details 4u4 exam 1h 40m. 3 sections. (90 mks??). section a,b...

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