Organic Pathways

Question 1

Alkane -> Halogenoalkane

Answer 1

Free Radical Substitution - Initiation, Propagation, Termination, UV Light

Question 2

Alkene -> Alkane

Answer 2

+ Hydrogen, Nickel Catalyst at 150 Degrees - Margerine (Partial Hydrogenation of liquid oils to make more solid and spreadable)
OR
Cracking - Platinum Catalyst, 500 Degrees

Question 3

Alkene -> Halogenoalkane

Answer 3

+ HBr (major product due to inductive effect is Br goes to carbon with most surrounding carbons)
OR
Br2 (l) (Bubble gas through halogen dissolved in inert solvent) - Dihalogenoalkane
OR
Br2 (aq) Hydroxyhalogenoalkane
Colour change (Orange - Colourless)

Question 4

Halogenoalkane -> Alkene

Answer 4

+ conc KOH in ethanol, Heat under reflux (OH-) acts as base
Forms EZ Isomers +KBR +H2O

Question 5

Alkene -> Alcohol

Answer 5

+H2O with dilute phosphoric acid catalyst at >100 Degrees
OR
For diol +[O] + H2O and acidified KMnO4 - purple to colourless

Question 6

Alcohol -> Alkene

Answer 6

Heat under reflux with conc phosphoric acid -> alkene + H2O

Question 7

Halogenoalkane -> Alcohol

Answer 7

warm with ethanol (common solvent), add nitric acid and silver nitrate which forms precipitate to identify halogen

Question 8

Alcohol -> Chloroalkane

Answer 8

Alcohol + PCl5 -> Chloroalkane + POCl3 + HCl (steamy white fumes)

Question 9

Alcohol -> Bromoalkane

Answer 9

Sulfuric acid + KBr -> HBr + KHSO4
Alcohol + HBr -> Bromoalkane + H2O
Add 50% sulfuric acid then add solid KBr and warm.
Don’t use conc sulfuric, otherwise HBr formed will be oxidised to Br2

Question 10

Alcohol -> Iodoalkane

Answer 10

2P + 3I2 -> 2PI3
3 Alcohol + PI3 -> 3 Iodoalkane + H3PO3 (Phosphorus Acid)

Question 11

1* Alcohol -> Aldehyde

Answer 11

Alcohol + [O] -> Aldehyde (acidified Potassium Dichromate + H2SO4)
Distill immediately
Orange -> Green

Question 12

1* Alcohol -> Carboxylic Acid

Answer 12

Alcohol + 2[O] -> Carboyxlic Acid
Potassium Dichromate + H2SO4
Heat Under Reflux
Orange-> Green

Question 13

2* Alcohol -> Ketone

Answer 13

Alcohol+ [O] -> Ketone
Potassium Dichromate + H2SO4
Heat Under Reflux
Orange -> Green

Question 14

Ketone -> 2* Alcohol

Answer 14

Ketone + 2[H] -> 2* Alcohol
Lithal in dry ether
React with strong dilute acid

Question 15

Aldehyde -> 1* Alcohol

Answer 15

Aldehyde + 2[H] -> 1* Alcohol
Lithal in dry ether
React with strong dilute acid

Question 16

Carboyxlic Acid -> 1* Alcohol

Answer 16

Carboyxlic Acid + 4[H] -> 1* Alcohol + H2O
Lithal in dry ether
React with strong dilute acid

Question 17

Aldehyde -> Hydroxynitrile

Answer 17

+HCN/KCN -> Hydroxynitrile
pH 8
Racemic mix

Question 18

Halogenoalkane -> Amine

Answer 18

+ 2NH3 -> Amine + NH4Br

Question 19

Halogenoalkane -> Nitrile

Answer 19

+KCN -> Nitrile +KBr
Heat under reflux with KCN dissolved in ethanol
increases carbon chain by 1

Question 20

Nitrile -> Amine

Answer 20

+ 4[H] -> Amine
Lithal in dry ether
react with strong dilute acid

Question 21

Nitrile -> Carboyxlic Acid

Answer 21

Acidic ( +2H2O + HCL -> Carboyxlic Acid + NH4Cl)
Alkaline (+H2O + NaOH -> Salt + NH3)
- react salt with HCl to liberate parent acid
Heat under Reflux with dilute acid/strong base

Question 22

Amine -> Amide

Answer 22

+ Acyl Chloride -> Amide +HCl
Steamy White Fumes (Fume Cupboard)
Cold Conc Amine

Question 23

Amide -> Amine

Answer 23

+ 4[H] -> Amine + H2O
Warm with Lithal in dry ether
Hydrolysis with strong dilute acid

Question 24

Carboxylic Acid -> Acyl Chloride

Answer 24

PCl5 -> Acyl Chloride + POCl3 +HCl
Steamy white fumes, test for OH group
To distinguish CA from Alcohols, react with carbonate - if bubbles then CA

Question 25

Acyl Chloride -> Carboxylic Acid

Answer 25

+H2O -> CA + HCl
Steamy white fumes - fume cupboard

Question 26

Amide -> Carboxylic Acid

Answer 26

Acidic - +H2O +HCl -> CA +NH4Cl
Alkaline - +H2O +NaOh -> CA + NH3
Heat under relux with strong dilute acid/strong base

Question 27

Alcohol + Carboxylic Acid -> Ester

Answer 27

Ester + Water
Warm with conc sulfuric acid

Question 28

Ester -> Alcohol + Carboxylic Acid

Answer 28

Acidic - +H2O -> Alcohol + CA
Alkaline - +Na OH -> Alcohol + Salt
Heat under reflux with dilute sulfuric/strong base
React salt with HCl to liberate parent acid

Question 29

Acyl Chloride -> Ester

Answer 29

-> Ester + HCl
steamy white fumes - in fume cupboard

Question 30

Acyl Chloride -> Amide

Answer 30

+NH3 -> Amide (e.g CH3CONH2) + HCl
steamy white fumes (fume cupboard)

Question 31

Halogenoalkane + Benzene -> Alkyl Benzene

Answer 31

Benzene + RCl -> R-Benzene + HCl
Catalyst : AlCl3
Anhydrous
Electrophilic Substitution

Question 32

Benzene -> Halogeno Benzene

Answer 32

+ Br2 -> Bromo-benzene + HBr
Catalyst : FeBr3
Anhydrous
Electrophilic Substitution

Question 33

Benzene + Acyl Chloride -> Acyl Benzene

Answer 33

+ ROCl -> Benzene-OR + HCl
Catalyst : AlCl3
Anhydrous
Electrophilic Substitution

Question 34

Benzene -> Nitrobenzene

Answer 34

+HNO3 -> Benzene-NO2 + H2O
Catalyst : H2SO4
Temp : 50 degrees
Electrophilic Substitution

Question 35

Nitrobenzene -> Phenylamine

Answer 35

+ 6[H] -> Benzene-NH2 +2H2O
Add conc HCl and tin
Warm
Hydrolysis with strong base to liberate strong base from salt intermediate

Question 36

Phenylamine -> Amide

Answer 36

+ Acyl chloride -> CH3CONH-benzene + HCl

Question 37

Make Gringard

Answer 37

halogenoalkane + Mg -> RMgBr
Heat under relfux with dry ether

Question 38

Gringard -> Alcohol

Answer 38

+ Aldehyde
in dry ether
hydrolysis with dilute strong acid

Question 39

Gringard -> Carboxylic Acid

Answer 39

+ CO2 + H2O -> CA + Mg(OH)Br
dry ether
solid CO2
+ strong dilute acid

Question 40

Phenol -> Bromophenol

Answer 40

Phenol + 3Br2 -> 3-bromophenol + 3HBr
orange -> colourless
white precipitate

Question 41

Phenol -> Nitrophenol

Answer 41

Phenol + 2HNO3 -> nitrophenol + H2O

Question 42

Phenol -> Ester

Answer 42

+ Acyl Chloride -> Ester + HCl