AS Mechanisms Flashcards
Halogenoalkane + hydroxide ions (aq)
RX + OH^-
Mechanism: Nucleophilic substitution
Product: alcohol and halide
Halogenoalkane + cyanide ions
RX + CN^-
Reactant: KCN or HCN (ethanolic)
Chain lengthens by 1 C
Mechanism: Nucleophilic Substitution
Product: nitrile and halogen ion (halide)
Halogenoalkane + ammonia
RX + NH3
Mechanism: Nucleophilic Substitution
Products: amine and ammonium ion (NH4X)
Conditions: sealed copper tube, excess ammonia
Reactant: warm conc. ethanolic ammonia
Ammonia acts as a Nucleophile and then a base
Halogenoalkane + hydroxide ions (ethanolic)
RX + OH^-
Product: alkene + halide (e.g potassium bromide ) + water
Reactant: NaOH or KOH
Mechanism: Elimination
Conditions: ethanolic
Hydroxide ion acts as a base as it accepts a proton
Alkenes + bromine (halogen)
R1=R2 + X2
Product: dibromoalkane
Reactant: Br2
Mechanism: Electrophilic Addition
Conditions:
Alkenes + sulfuric acid
R1=R2 + H2SO4
Product: alkylhydrogensulfate
Reactant: conc. H2SO4
Mechanism: Electrophilic Addition
Conditions: conc. sulfuric acid
Name of the intermediate
Carbocation
Preference of intermediates
Tertiary>secondary>primary
More stability is created by a tertiary carbocation having more electron donating alkyl groups than a primary carbocation
Alkenes + hydrogen bromide
R1=R2 + HX
Product: bromoalkane (Halogenoalkane)
Reactant: HX
Mechanism: Electrophilic Addition
Conditions:
Free radical sub of ozone
(UV light) Cl2 —> 2Cl’
Alkanes + bromine
Mechanism: Free radical substitution
Conditions: UV light
Free radical step 1
Initiation
Zero radicals —> 2 radicals
Free radical step 2
Propagation
One radical —> one radical
Reaction 1: react with new radical formed from initiation
Reaction 2: Reaction 1 product with original reactant
Alcohols + sulfuric acid or phosphoric acid
R-OH + H2SO4 or H3PO4
Product: Alkenes
Reactant:
Mechanism: Acid catalysed elimination
Conditions:
Catalyst: H2SO2 or H3PO4
Alkene + water
R1=R2 + H20
Product: Alcohol
Reactant: H20
Mechanism: ——- acid catalysed addition, hydration
Conditions:
Catalyst: H3PO4