(a) Pathways for the synthesis of organic molecules

 Alkanes
 

Organic reactant	Reagent	Conditions	Organic Products
Alkane  ethane  C2H6	halogen  bromine  Br2	UV light	halogenoalkane  bromoethane  CH3CH2Br
Alkane  ethane  C2H6	halogen  chlorine  Cl2	UV light	halogenoalkane  chloroethane  CH3CH2Cl

Alkenes
 

Organic reactant	Reagent	Conditions	Organic Products
Alkene  ethene  C2H4	halogen  bromine  Br2	inert solvent	halogenoalkane  1,2-dibromoethane  CH2BrCH2Br
unsymmetric alkene  prop-1-ene  CH3CHCH2	hydrogen halide  hydrogen bromide  HBr	inert solvent	halogenoalkane  2-bromopropane  CH3CHBrCH3
<FONT FACE="Arial">1. What are the product(s) formed if the following is heated in (i) cold KMnO4; (ii) hot KMnO4? 1. CH<SUB>2</SUB>=CH<SUB>2</SUB>CH<SUB>3</SUB>CH<SUB>2</SUB>=CH<SUB>2</SUB>CH<SUB>3</SUB> 2. CH4 </FONT> <BR><FONT FACE="Arial">3. CH<SUB>3</SUB>-CH<SUB>2</SUB>=CH<SUB>2</SUB>=CH<SUB>2</SUB>-CH<SUB>3 </SUB></FONT> Alkene  ethene  C2H4	potassium manganate(VII)  KMnO4           Ht / KMnO4	alkaline solution             acidfied solution	ethane-1,2-diol  CH2OHCH2OH     carboxylic acid, ketone or CO2 if acid is HCOOH.

Arenes
 

Organic reactant	Reagent	Conditions	Organic Products
arene  benzene  C6H6	nitric acid  sulphuric acid	heat under reflux  below 60oC  concentrated acids	nitrobenzene  C6H5NO2
arene  methylbenzene  C6H5CH3	potassium manganate VII	alkaline conditions  heat under reflux	benzoic acid  C6H5COOH
arene  benzene  C6H6	chloroalkane  chloromethane  CH3Cl	anhydrous aluminium chloride as catalyst	arene  methylbenzene  C6H5CH3
arene  benzene  C6H6	acid chloride  ethanoyl chloride  CH3COCl	anhydrous aluminium chloride as catalyst	ketone  methylphenylketone  C6H5COCH3

Primary alcohols
 

Organic reactant	Reagent	Conditions	Organic Products
primary alcohol  ethanol  C2H5OH	aqueous potassium dichromate VI  dilute sulphuric acid	distil product	aldehyde  ethanal  CH3CHO
primary alcohol  ethanol  C2H5OH	aqueous potassium dichromate VI  dilute sulphuric acid	heat under reflux	carboxylic acid  ethanoic acid  CH3COOH
primary alcohol  ethanol  C2H5OH	hydrogen halide  hydrogen bromide  HBr	heat under reflux HBr formed in situ from KBr and conc. H2SO4	halogenoalkane  bromoethane  C2H5Br
primary alcohol  ethanol  C2H5OH	carboxylic acid  ethanoic acid  CH3COOH	concentrated H2SO4	ester  ethyl ethanoate  CH3COOC2H5
primary alcohol  ethanol  C2H5OH	acid chloride  ethanoyl chloride  CH3COCl		ester  ethyl ethanoate  CH3COOC2H5
primary alcohol  ethanol  C2H5OH	phosporus pentachloride		halogenoalkane  chloroethane  C2H5Cl

Secondary alcohols
 

Organic reactant	Reagent	Conditions	Organic Products
secondary alcohol  propan-2-ol  CH3CH(OH)CH3	aqueous potassium dichromate VI  sulphuric acid	conc. acid  heat under reflux	ketone  propanone  CH3COCH3
secondary alcohol  propan-2-ol  CH3CH(OH)CH3	hydrogen halide  hydrogen bromide  HBr	heat under reflux HBr formed in situ from KBr and conc. H2SO4	halogenoalkane  2-bromopropane  CH3CH2(Br)CH3
secondary alcohol  propan-2-ol  CH3CH(OH)CH3	carboxylic acid  ethanoic acid  CH3COOH	concentrated H2SO4	ester  2-propylethanoate  CH3COOCH(CH3)2
secondary alcohol  propan-2-ol  CH3CH(OH)CH3	acid chloride  ethanoyl chloride  CH3COCl		ester  2-propylethanoate  CH3COOCH(CH3)2
secondary alcohol  propan-2-ol  CH3CH(OH)CH3	phosporus pentachloride		halogenoalkane  2-chloropropane  CH3CH2(Cl)CH3

Tertiary alcohols
 

Organic reactant	Reagent	Conditions	Organic Products
tertiary alcohol  2-methylpropan-2-ol  (CH3)3OH	hydrogen halide  hydrogen bromide  HBr	heat under reflux HBr formed in situ from KBr and conc. H2SO4	halogenoalkane  2-bromo-2-methylpropane  (CH3)3Br
tertiary alcohol  2-methylpropan-2-ol  (CH3)3COH	carboxylic acid  ethanoic acid  CH3COOH	heat  concentrated H2SO4	ester  CH3COOC(CH3)3
tertiary alcohol  2-methylpropan-2-ol  (CH3)3OH	acid chloride  ethanoyl chloride  CH3COCl		ester  CH3COOC(CH3)3
tertiary alcohol  2-methylpropan-2-ol  (CH3)3OH	phosporus pentachloride	dry	(CH3)3Cl

Carboxylic acids
 

Organic reactant	Reagent	Conditions	Organic Products
carboxylic acid  ethanoic acid  CH3COOH	alcohol  ethanol  C2H5OH	heat  concentrated H2SO4	ester  ethyl ethanoate  CH3COOC2H5
carboxylic acid  ethanoic acid  CH3COOH	lithium aluminium hydride	dissolved in dry ether	alcohol  ethanol  C2H5OH
carboxylic acid  ethanoic acid  CH3COOH	phosphorus pentachloride	dry	acid chloride  ethanoyl chloride  CH3COCl

Primary amines
 

Organic reactant	Reagent	Conditions	Organic Products
primary amine  ethylamine  C2H5NH2	acid  hydrochloric acid  HCl	aqueous solution	salt  alkyl ammonium chloride  C2H5NH3+Cl-

Halogenoalkanes
 

Organic reactant	Reagent	Conditions	Organic Products
halogenoalkane  bromoethane  C2H5Br	hydroxide ion  sodium hydroxide  NaOH	aqueous solution	alcohol  ethanol  C2H5OH
halogenoalkane  bromoethane  C2H5Br	hydroxide ion  potassium hydroxide  KOH	heat and distil off product  ethanolic solution	alkene  ethene  C2H4
halogenoalkane  bromoethane  C2H5Br	cyanide ion  potassium cyanide  KCN	heat under reflux in ethanolic solution	nitrile  propanonitrile  C2H5CN
halogenoalkane  bromoethane  C2H5Br	ammonia	heat with concentrated ammonia in a sealed tube	amine  ethylamine etc  C2H5NH2 ; (C2H5)2NH etc

Nitrobenzene
 

Organic reactant	Reagent	Conditions	Organic Products
nitrobenzene  C6H6NO2	concentrated hydrochloric acid and tin HCl and Sn	heat under reflux	phenylamine  C6H6NH2

Phenylamine
 

Organic reactant	Reagent	Conditions	Organic Products
phenylamine  C6H5NH2	nitrous acid  HNO2	below 5oC  NaNO2 and dil HCl	diazonium salt  benzen diazonium chloride C6H5N2+Cl-

Diazonium salt
 

Organic reactant	Reagent	Conditions	Organic Products
diazonium salt  benzen diazonium chloride C6H5N2+Cl-	phenol  C6H5OH	below 5oC	azo dye  C6H5N2C6H5OH
diazonium salt  benzene diazonium chloride C6H5N2+Cl-	2-naphthol	below 5oC	azo dye  C10H6(OH)N2C6H5

Ketones
 

Organic reactant	Reagent	Conditions	Organic Products
ketone  propanone  (CH3)2CO	hydrogen cyanide	in alkaline conditions  potassium cyanide used as source of HCN	2-hydroxy -2-methylpropanonitrile  CH3C(OH)(CH3)CN
ketone  propanone  (CH3)2CO	2,4-  dinitrophenylhydrazine  C6H3(NO2)2NHNH2	dil. sulphuric acid	2,4-  dinitrophenyhydrozone  C6H3(NO2)2NHNC(CH3)2
ketone  propanone  (CH3)2CO	iodine or sodium iodide and chloate(I)	alkaline conditions	tri-chloromethane  (iodoform)
ketone  propanone  (CH3)2CO	sodium borohydride  NaBH4	aqueous solution	secondary alcohol  propan-2-ol  CH3CH(OH)CH3

Aldehydes
 

Organic reactant	Reagent	Conditions	Organic Products
aldehyde  ethanal  CH3CHO	hydrogen cyanide	in alkaline conditions  potassium cyanide used as source of HCN	2-hydroxypropanonitrile  CH3CH(OH)(CN)
aldehyde  ethanal  CH3CHO	2,4-  dinitrophenylhydrazine  C6H3(NO2)2NHNH2	dilute sulphuric acid	2,4-  dinitrophenyhydrozone  C6H3(NO2)2NHNCHCH3
aldehyde  ethanal  CH3CHO	ammoniacal silver nitrate solution  (Tollen's reagent)	warm in water bath	carboxylic acid  ethanoic acid  CH3COOH
aldehyde  ethanal  CH3CHO	iodine or sodium iodide and chloate(I)	alkaline conditions	tri-chloromethane  (iodoform)
aldehyde  ethanal  CH3CHO	sodium borohydride  NaBH4	aqueous solution	alcohol  ethanol  C2H5OH

Acid chlorides
 

Organic reactant	Reagent	Conditions	Organic Products
acid chloride  ethanoyl chloride  CH3COCl	water  H2O		carboxylic acid  ethanoic acid  CH3COOH
acid chloride  ethanoyl chloride  CH3COCl	carboxylic acid  ethanoic acid  CH3COOH	no water	ester  ethyl ethanoate  CH3COOC2H5
acid chloride  ethanoyl chloride  CH3COCl	ammonia  NH3	conc. ammonia	amide  ethanamide  CH3CONH2
acid chloride  ethanoyl chloride  CH3COCl	primary amine  phenylamine  C6H5NH2		N-phenylethanamide  CH3CONHC6H5

Nitriles
 

Organic reactant	Reagent	Conditions	Organic Products
nitrile  ethanonitrile  CH3CN	water	acidic	carboxylic acid  ethanoic acid  CH3COOH
nitrile  ethanonitrile  CH3CN	water	alkaline	salt  sodium ethanoate  CH3COONa
nitrile  ethanonitrile  CH3CN	lithium aluminium hydride	dry ether solution	amine  ethylamine  CH3CH2NH2

Amides
 

Organic reactant	Reagent	Conditions	Organic Products
amide  ethanamide  CH3CONH2	phosphorus V oxide		nitrile  ethanonitrile  CH3CN
amide  ethanamide  CH3CONH2	bromine	aqueous alkali	amine  methylamine  CH3NH2

Esters
 

Organic reactant	Reagent	Conditions	Organic Products
ester  ethyl ethanoate  CH3COOC2H5	water	conc. sulphuric acid	ethanol, ethanoic acid  C2H5OH, CH3COOH

 Polymers
 

Organic reactant	Reagent	Conditions	Organic Products
monomer  ethene   C2H4		O2 catalyst  200oC  2000 atm. P	polymer  polyethene  -(-CH2-CH2-)n-
monomer  propene		AlR3+TiCl3  catalysts  100oC10atm  in heptane	polymer  polypropene  -(-CH(CH3)-CH2-)n-
monomer  chloroethene		heat in inert  solvent  with initiator	polymer  polychloroethene  -(-CHCl-CH2-)n-
monomer  tetrafluroethene		heat + press  (NH4)2S2O8  catalyst	polymer  polytetrafluroethene  -(-CF2-CF2-)n-
monomer  phenylethene		initiator	polymer  polyphenylethene  -(-CH(C6H5)-CH2-)n-
monomer  benzene-  1,4-dicarboxylic acid  H-O-COC6H5-CO-O-H	monomer  ethane-1,2-diol  H-O-CH2-CH2-O-H		polyester  terylene  H-O-(COC6H5-CO-O-  CH2-CH2-O)n-H
monomer  hexanedioic acid  HOOC-(CH2)4-COOH	monomer  1,6-diaminohexane  H2N-(CH2)6-NH2		polymer  polyamide (nylon-6.6)  HO-(OC-(CH2)4-CO-  HN-(CH2)6-NH)n-H

(b) Practical Techniques used in Organic Chemistry "

Heating under reflux
Simple distillation
Fractional distillation
Steam distillation
recrystallisation
 
 

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Newly revised: January 17, 2000.

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(Notes on Organic Synthesis: A Summary)