Organic Synthesis

Question 1

Alkene to Alkane

Answer 1

H₂

Nickel Catalyst

150°C

Question 2

Alkane to Halogenoalkane

Answer 2

UV light

Hydrogen Halide

Free Radical Substitution

Question 3

Alkene to Halogenoalkane

Answer 3

Hydrogen Halide

Question 4

Halogenoalkane to Alkene

Answer 4

Potassium Hydroxide

Ethanol

Heat

Question 5

Alkene to Alcohol

Answer 5

H₂O (steam)

300°C

60-70 atm

Phosphoric (V) acid catalyst

Question 6

Alcohol to Alkene

Answer 6

Sulfuric Acid

High temperature

Question 7

Halogenoalkane to Alcohol

Answer 7

Potassium Hydroxide

Reflux

Question 8

Alcohol to Halogenoalkane

Answer 8

PCl₅/HCl

KBr - Reflux

HI

Question 9

Halogenoalkane to Amine

Answer 9

Conc Ammonia (NH₃)

Ethanol

Sealed Tube

Question 10

Primary Amine to Secondary/Tertiary Amine

Answer 10

React with a halogenoalkane

Question 11

Amine to Polyamide

Answer 11

Dicarboxylic acid and diamine

Question 12

Amine to Amide

Answer 12

Acyl Chloride

Ammonia

Question 13

Alcohol to Ketone

Answer 13

Potassium Dichromate

Reflux

Question 14

Ketone to Secondary Alcohol

Answer 14

LiAlH₄

Dry Ether

Question 15

Primary Alcohol to Aldehyde

Answer 15

Potassium Dichromate

Reflux and Distill product off

Question 16

Aldehyde to Primary Alcohol

Answer 16

LiAlH₄

Dry Ether

Question 17

Alcohol/Aldehyde to Carboxylic Acid

Answer 17

Potassium Dichromate

Reflux and Distill off later

Question 18

Carboxylic Acid to Alcohol

Answer 18

LiAlH₄

Question 19

Carboxylic Acid to Ester

Answer 19

Conc Sulfuric Acid

Alcohol

Warm in a bath

Question 20

Alcohol to Ester

Answer 20

Acyl Chloride

Question 21

Halogenoalkane to Nitrile

Answer 21

Potassium Cyanide

Reflux

Question 22

Nitrile to Carboxylic Acid

Answer 22

HCl and water

NaOH and water

Question 23

Nitrile to Amine

Answer 23

LiAlH₄

Dry ether

Question 24

Nitrile to Amide

Answer 24

H₂O

Question 25

Amide to Nitrile

Answer 25

Phosphor Oxide P₄O₁₀

Question 26

Grinards Reagent

Answer 26

Used to extend carbon chain **Preparation** Halogenoalkane is dissolved in dry ether and reacted with magnesium **CH3CH2Br + Mg → CH3CH2MgBr** **Reactions** Methanal produces a primary alcohol **CH3CH2MgBr + HCHO → CH3CH2CH2OH + Mg(OH)Br** Longer aldehydes produce a secondary alcohol **CH3CH2MgBr + CH3CHO → CH3CH2CH(OH)CH3 + Mg(OH)Br** Ketones produce a tertiary alcohol **Ch3CH2MgBr + CH3COCH3 → CH3CH2C(CH3)(OH)CH3 + Mg(OH)Br** Carbon dioxide produces carboxylic acids **CH3CH2MgBr + CO2 → CH3CH2COOH + Mg(OH)**

Question 27

Refluxing

Answer 27

When you want to ensure that none of the products can escape from the reflux vessel All gases are condensed back into a liquid and run back into pear shaped flask Water in at the bottom Water out at the top

Question 28

Ketone to HydroxyNitrile

Answer 28

Hydrogen Cyanide Potassium Cyanide and Sulfuric Acid

Question 29

Aldehyde to Hydroxynitrile

Answer 29

Hydrogen Cyanide Potassium Cyanide and Sulfuric Acid

Question 30

Ester to Carboxylic Acid

Answer 30

Water with Dilute Acid Reflux

Question 31

Acyl Chloride to Ester

Answer 31

Cold Ethanol

Question 32

Acyl Chloride to Amide

Answer 32

Concentrated Ammonia

Question 33

Filtration

Answer 33

If the product is a solid, it can be separated by filtration using a buchner finnel with suction from a water pump

Question 34

Steam Distillation

Answer 34

Distillation with steam at 100°C allows for the separation of compounds that decompose if heated at their boiling temperatures Only works for compounds that do not mix with water Leaves behind reagents and products that are soluble in water

Question 35

Solvent Extraction

Answer 35

1. add mixture to separating funnel and mix with water 2. add organic solvent and shake 3. add salt to organic product 4. open tap and separate 5. remove water by adding anhydrous salt such as calcium chloride

Question 36

Recrystallisation

Answer 36

1. dissolve solid in minimum volume of hot solvent 2. filter through fluted paper and funnel 3. cool to allow crystals to form 4. filter using buchner funnel 5. dry

Question 37

Washing and Drying to Purify Organic Liquids

Answer 37

1. wash with water 2. dry 3. wash again 4. leave in warm place or mix with a drying agent

Question 38

Fractional Distillation

Answer 38

* column packed with glass beads to give maximum surface area * there is a vent in system to prevent pressure build up * flask may need to be surrounded with ice if liquid has a low boiling point * mixture heated so that the thermometer is at the temperature of the boiling point