10B.3 Flashcards
what are the 4 substitution reactions that are required to know and their nucleophile
reaction 1: RX ——-H2O/warm—–> ROH + HX
nucleophile = (OH-)
reaction 2: RX —KOH(aq)/heat under reflux—-> ROH + KX
nucleophile = (OH-)
reaction 3: RX –KCN/heated under reflux–> RCN + KX
nucleophile = CN-
reaction 4: RX –NH3/heated in sealed tube–> RNH2 + HX
nucleophile = NH3-
what are nitrile
they are organic compounds containing the C-CN group
the potassium cynide in the substitution reaction is
dissolve in ethanol under reflux
why do we substitute KCN with halogenoalkanes
- to make the carbon chain longer (since there is an extra carbon
- an important way to synthesize more complex compounds
what is the risk with KCN
very toxic
what is a primary amine
a compound containing C-NH2 group
why does the substitution reaction between ammonia and RX need to be in a sealed tube
to stop the ammonia gas from escaping
what is the 3 steps of the substitution reaction of NH3 with R to form a primary amine
step one:
RX + NH3 ——-> RNH2 (base) + HI (acid)
step two:
RNH2 + HI ——–> RNH3+ + I-
step 3:
RNH3^+I^- + NH3(excess) —–> RNH2 + NH4^+I^-
final equation:
RX + 2NH3 ——> RNH2 + NH4^+I^-
how do we get a high yield of RNH2
using excess ammonia
what is nucleophile substitution
it is when the attacking nucleophile replaces an atom or a group in a molecule
what is a mechanism for the substitution of RX by KOH
page 269
what is a mechanism for the substitution of RX by NH3
page 269
if we change the solvent in the substitution of RX by KOH with ethanol instead of water what happens
an elimination instead of a nucleophile substitution would occur since the OH- would act as a base rather than a nucleophile, reaction with the hydrogen that’s attached to the c that’s next to the c bearing the halide
what is ethanolic
it is a solution in which the solvent is ethane
