mechanisms

Question 1

how do we get from an alkane to a halogenoalkane?

Answer 1

free radical substitution
condition: UV light
reagent: X2
Fission: homolytic

Question 2

what is a radical?

Answer 2

unpaired electron

Question 3

what is meant by ‘substitution’ in free rad?

Answer 3

replace H atom for x atom

Question 4

what is the mechanism for converting a haloalkane into an alcohol, nitrile or amine?

Answer 4

nucleophilic substitution

replacing X for nucleophile

Question 5

what acts as a nucleophile in nucleophilic substitution?

Answer 5

alcohol; OH-
amine; NH3
nitrile; CN-

Question 6

what are the reagents and conditions for nucleophilic sub to make alcohols?

Answer 6

warm, aqueous sodium hydroxide

Question 7

what are the reagents and conditions for nucleophilic sub to make amines?

Answer 7

excess ammonia, warm, ethanol, sealed container

Question 8

what are the reagents and conditions for nucleophilic sub to make nitriles?

Answer 8

potassium cyanide, warm, ethanol

Question 9

what is the OTHER product made during nucleophilic substitution for alcohols, amines and nitriles?

Answer 9

alchohol; NaX

amine; NH4+X-

nitrile; KX

Question 10

what mechanism gives an alkene from a haloalkane?

Answer 10

elimination (losing H atom and X atom)

Question 11

what are the reagents and conditions for elimination of haloalkanes?

Answer 11

reflux in ethanol/ hot ethanolic potassium/ sodium hydroxide

Question 12

what does the OH- act as in elimination of haloalkanes?

Answer 12

base (proton acceptor)

Question 13

what mechanism do alkenes mainly undergo?

Answer 13

electrophilic addition

Question 14

how can alkanes be made from alkenes?

Answer 14

hydrogenation (adding 2 H atoms)

condition; Ni catalyst

Question 15

how can alkenes be used to make haloalkanes or dihaloalkanes?

Answer 15

electrophilic addition
add 2X atoms for dihaloalkane
add HX for haloalkane

Question 16

how can alkenes be used in industry to produce alcohols?

Answer 16

hydrated in 300 degrees, 60 atm and using a concentrated phosphoric acid catalyst

Question 17

how can alkenes get organic hydrogen sulphates?

Answer 17

electrophilic addition
reagent; conc H2SO4
condition; room temp

Question 18

how can organic hydrogen sulfates produce alcohols?

Answer 18

hydrolysed using water

sulfuric acid is regenerated so acts as a catalyst

Question 19

how can alcohols go to alkenes?

Answer 19

elimination

reagent; conc sulfuric acid
conditions; heat

there must be a H on an adjacent C to be removed