Organic synthesis chp 28

Question 1

what is a nitrile group

Answer 1

• CN

Question 2

how can nitriles be formed from haloalkanes

Answer 2

• by reacting haloalkanes with sodium/potassium cyanide in ethanol

Question 3

draw the reaction mechanism for the formation of a nitrile via a reaction with haloalkane

what type of reaction is this

Answer 3

nuelcophilic substituion

Question 4

How can nitriles be formed from aldehydes and ketones

what is used in industry to improve safety

Answer 4

• aldehyde/ketone reacts with mixture of NaCN and sulfuric acid in nucleophilic addition reaction
• product is a hydroxynitrile

Question 5

draw reaction mechanism of formation of nitrile group from ketone

Answer 5

Question 6

when can nitrile compounds act as intermediates

Answer 6

• in synthesis of organic compounds such as amines and carboxylic acids

Question 7

what conditions are needed for the reduction of nitriles

Answer 7

by reacting nitrile with hydrogen with nickel catalyst

Question 8

what is the product of hydrolysing nitrile compounds

what conditions are needed for reaction

Answer 8

• form carboxylic acids via heating with dilute aq acid

Question 9

define alkylation

Answer 9

• reaction that transfers alkyl group from haloalkane to benzene ring

Question 10

what conditions are needed for alkylation reactions to occur

Answer 10

occur in presence of halogen carrier

Question 11

define acylation

Answer 11

• benzene reacts with acyl chloride in present of AlCl3
• forms ketone

Question 12

How to filter under reduced pressure

Answer 12

• connect pressure tubing to tap and buchner flask
• Secure Buchner funnel to flask using rubber bung
• Turn on tap
• Test suction by placing hand over funnel to feel force
• wet filter paper with solvent, observe it being drawn against funnel holes.
• Slowly pour reaction mixture onto filter paper in funnel.
• Use solvent to ensure all crystals collect in funnel.
• Wash crystals with solvent in funnel, allow to dry under suction

Question 13

process of recrystallisation from crystal product of filteration

Answer 13

• pour quantity of chosen solvent into conical flask
• warm using water bath or bunsen burner
• tip impure sample into 2nd conical flask
• slowly add solvent to impure sample until dissolves
  ^add minimum amount needed to
• once solid dissolves, allow solution to cool
• crystals of desired product should form
• filter crystals under reduced pressure

Question 14

how to determine melting point

Answer 14

• ensure solid is dry and free flowing
• flame neck of melting tube, allow to cool
• fill tube with 3cm^3 crystals
• measure melting point

Question 15

how can melting point be determined using electrically heated apparatus

Answer 15

• place capillary tube containing sample into apparatus
• observe sample through magnifying window
• once melting record melting point
• allow to cool
• test again but as reach rough point slow temp rise to get more exact point

Question 16

How can an oil bath/thiele tube be used to measure melting point

Answer 16

• set up oil bath
• attach capillary tube containing sample to thermometer
• insert thermometer & tube into oil bath/thiele tube
• using micro-burner slowly heat side of oil bath/thiele tube
• when solid starts melting record temp at which all is melted
• repeat and slow when reaching temp to get more exact result

Question 17

Draw the mind map of the reactions of phenol

Answer 17