Organic Synthesis Pathways

Question 1

Haloalkanes –> Alcohols*

Answer 1

Nucleophilic substitution. NaOH(aq)/heat under reflux. Alkaline hydrolysis.

Question 2

Haloalkanes –> Nitriles*

Answer 2

Nucleophilic substitution. KCN/heat under reflux.

Question 3

Primary Chlororalkanes –> Primary Amines

Answer 3

Two-step synthesis. 1. Nucleophilic substitution. 2. Base displacement. Excess NH3 dissolved in methanol and add NaOH(aq)

Question 4

Benzene –> Nitrobenzene*

Answer 4

Electrophilic substitution. Concentrated HNO3 and H2SO4, at 50 degrees to prevent further subsitution.

Question 5

Nitrobenzene –> Phenylamine

Answer 5

Reduction. Tin and concentrated HCl/heat under reflux.

Question 6

Phenylamine –> Phenylammonium ion

Answer 6

Nuetrilisation. HCl and rtp.

Question 7

Benzene –> Halobenzene*

Answer 7

Electrophilic substitution. Anhydrous AlX3 and rtp.

Question 8

Benzene + Chloroalkane –> Alkyl Benzene*

Answer 8

Electrophilic substitution. Anhydrous AlCl3/FeCl3

Question 9

Benzene + Acyl Chloride –> Phenylketone*

Answer 9

Electrophilic substitution. Anhydrous AlCl3/FeCl3

Question 10

Phenol to 2,4,6 tribromophenol

Answer 10

Electrophilic substitution. 3Br2 and rtp. White ppt forms.

Question 11

Phenol to 2-nitrophenol and 4-nitrophenol

Answer 11

Electrophilic substitution. HNO3 and rtp

Question 12

Phenol –> phenoxide ion

Answer 12

salt formation/neutrislation/acidity reaction. NaOH and rtp.

Question 13

Phenol –> phenyl ester

Answer 13

Esterfication. rtp.

Question 14

Aldehydes –> carboxylic acids

Answer 14

Oxidation. K2Cr2O7/H2SO4/heat under reflux.

Question 15

Aldehydes –> primary alcohols*

Answer 15

Reduction. Nucleophilic addition. NaBH4/H20 and heat.

Question 16

Aldehydes –> secondary alcohols*

Answer 16

Reduction. Nucleophilic addition. NaBH4/H20 and heat.

Question 17

Aldehydes –> 2-hydroxy nitriles*

Answer 17

Nucleophilic addition. NaCN/H2SO4 and heat

Question 18

Ketones –> 2-hydroxy nitriles*

Answer 18

Nucleophilic addition. NaCN/H2SO4 and heat

Question 19

Nitriles (including 2-hydroxynitriles) –> primary amines)

Answer 19

Reduction. H2/Ni/ heat

Question 20

Nitriles (including 2-hydroxynitriles) –> carboxylic acids)

Answer 20

Acid hydrolysis. Strong acid ie HCl.

Question 21

Carboxylic acid –> carboxylate ion

Answer 21

Neutralisation. NaOH (aq)

Question 22

Carboxylic acid + alcohol –> ester

Answer 22

Esterification. Concentrated H2SO4 and heat

Question 23

Carboxylic acid –> acyl chloride

Answer 23

Preparation of an acyl chloride. rtp in a fume cupboard.

Question 24

Dicarboxylic acid + diol –> polyester

Answer 24

Condensation polymerisation.

Question 25

Acid anhydride + alcohol --> ester

Answer 25

Esterification. rtp

Question 26

Acyl chloride --> carboxylic acid

Answer 26

Hydrolysis. rtp

Question 27

Acyl chloride + alcohol --> ester

Answer 27

Esterfication. rtp

Question 28

Acyl chloride --> primary amide

Answer 28

Preparation of amide (neutralisation of HCL). rtp

Question 29

Acyl chloride + primary amine --> secondary amide

Answer 29

Preparation of amide (neutralisation of HCL). rtp

Question 30

Acyl chloride + secondary amine --> tertiary amide

Answer 30

Preparation of amide (neutralisation of HCL). rtp

Question 31

Ester --> carboxylic acids + alcohol

Answer 31

Acid Hydrolysis. HCl (aq) and heat

Question 32

Ester --> carboxlyate ion + alcohol

Answer 32

Alkaline Hydrolysis. NaOH (aq) and heat

Question 33

Amide --> carboxylic acid + alkylammonium ion

Answer 33

Acid Hydrolysis. HCl (aq) and heat

Question 34

Amide --> carboxylate ion and amine

Answer 34

Alkaline Hydrolysis. NaOH (aq) and heat

Question 35

Amine --> Alkyl ammonium ion

Answer 35

Neutralisation. HCl (aq) and rtp.

Question 36

Diamine + dicarboxylic acid --> polyamide

Answer 36

Condensation reaction.

Question 37

Amino acid + acid --> (NH3+)COOH

Answer 37

neutralisation

Question 38

Amino acid + alkali --> (NH2)COO-

Answer 38

neutralisation

Question 39

Amino acid --> polyamide (protien)

Answer 39

Condensation Polymerisation

Question 40

Alkane --> Haloalkane*

Answer 40

Free radical substitution. UV light/rtp. Excess X2

Question 41

Alkene --> Alkane

Answer 41

Reduction/Hydrogenation. H2/Ni catalyst/150 degrees

Question 42

Alkene --> Alcohol

Answer 42

Addition/Hydration. Steam and concentrated H3PO4 catalyst.

Question 43

Alkene --> Haloalkanes/Dihaloalkanes*

Answer 43

Electrophilic addition.(X2/XH). rtp

Question 44

Alkene --> Polyalkene

Answer 44

Addition Polymerisation. Ni catalyst/high pressure and temperature

Question 45

Primary Alcohol --> Aldehydes

Answer 45

Oxidation. excess alcohol. K2Cr2O7/H2SO4 (aq). Heat under distillation to remove aldehyde as it forms.

Question 46

Primary Alcohol --> Carboxylic acid

Answer 46

Oxidation. excess K2Cr2O7/H2SO4 (aq). Heat under reflux to oxidise aldehyde as it forms.

Question 47

Secondary Alcohol --> Ketone

Answer 47

Oxidation. K2Cr2O7/H2SO4 (aq). Heat under reflux

Question 48

Alcohols --> Alkene

Answer 48

Elimination/Dehydration. Conc H2SO4 or H3PO4. Heat under reflux. (the dehydration of unsymmetrical secondary or tertiary alcohols will give mixtures of alkenes)

Question 49

Alcohols --> Haloalkanes

Answer 49

Substitution. NaX/H2SO4 (aq). heat under reflux.

Question 50

electrophilic addition

Answer 50

alkenes, HCl/Cl2, HBr/Br2

Question 51

electrophilic substitution

Answer 51

benzene, NO2+, R+, RCO+, Cl+/Br+

Question 52

nucleophilic addition

Answer 52

carbonyl groups, CN- or H-

Question 53

nucleophilic substitution

Answer 53

halogenoalkanes, NH3, H2O, OH-, CN-

Question 54

Oxidation

Answer 54

primary alcohols --> aldehydes --> carboxylic acids secondary alcohols --> ketones K2Cr2O7/H2SO4