chem organic 18 Flashcards
(25 cards)
benzene + oxygen =
what are the products?
carbon dioxide + water
benzene —> bromobenzene
reagents, conditions, mechanism
reagents: bromine
conditions: iron (III) bromide catalyst FeBr3
mechanism: electrophilic substitution
benzene —> nitrobenzene
reagents, mechanism, electrophile?
reagents: conc nitric acid in the presence of conc sulfuric acid (catalyst)
mechanism: electrophilic substitution
electrophile: NO2+
why is nitration of benzene reaction important?
it is an important step in synthesising useful compounds
e.g explosive manufacture
benzene —> alkylbenzene
reagents, conditions, mechanism?
reagents: chloroalkane in the presence of anhydrous aluminium chloride catalyst
conditions: heat under reflux
mechanism: electrophilic substitution
benzene —> phenyl ketone
reagents, conditions, mechanism?
reagents: acyl chloride in the presence of anhydrous aluminium chloride catalyst
conditions: heat under reflux (50C)
mechanism: electrophilic substitution
phenol + bromine reaction….
reagent, conditions, product?
reagent: bromine water
conditions: room tem-p
product: 2,4,6- tribromophenol
what are phenols used in the production of…?
plastics, antiseptics, disinfectants and resins for paints
amines as bases react with acids to form…
ammonium salts
acyl chloride —> secondary amide
reagent, conditions
reagent: primary amide
conditions: room temp
how to form a primary amine in a one step reaction of halogenoalkanes with ammonia?
(ammonia dissolved in ethanol)
primary amines can be formed by the nucleophilic substitution reaction between halogenoalkanes and ammonia in a one step reaction. However, the primary amine can react in the same nucleophilic way in a successive series forming 2,3 amines and 4 ammonium salts.
NOT A GOOD METHOD DUE TO FURTHER REACTIONS
preparing amines from nitriles
(higher yield)
disadvantage of this metho
- convert halogenoalkane to nitrile by using KCN in aqueous ethanol (heat under reflux)
- reduce nitrile to amine by using LiAIH4 in ether or by reducing with H2 using a Ni catalyst
disadvantage of this method is that it is a two-step reaction that may therefore have low yield
also KCN is toxic
reducing nitroarenes to aromatic arenes
reagent, conditions, heating
reagent: Sn and HCl or Fe and HCl
conditions: heating
mechanism: reduction
e.g nitrobenzene + 6[H] —> phenylamine + 2H2O
acyl chloride –=-> secondary amide
reagent, conditions
reagent: primary amine
conditions: room temp
what is a zwitterion
the no charge form of an amino acid never occurs
the amino acid exists as a dipolar zwitterion
the ionic interaction between zwitterions explains the relatively high melting points of amino acids as opposed to the weaker hydrogen bonding that would occur in the no charge form
what is a grignard reagent for
to increase the length of the carbon chain
how to prepare a grignard reagent
a halogenoalkane is dissolved in dry ether and reacted with magnesium to produce the reactive grignard reagent
more about the grignard reagent
reactivity? charge?
highly reactive and the alkyl group can be considered to have a negative charge
The R-[+MgI] and so contains a nucleophilic carbon atom
Grignard reagent + methanal =
primary alcohol
grignard reagent + aldehydes (not methanal)
secondary alcohols
grignard reagent + ketones
tertiary alcohol
grignard reagent + CO2 =
carboxylic acid
why are anti-bumping granules used?
prevent vigorous, uneven boiling by making smaller bubbles form instead of larger bubbles
why are electric heaters sometimes used to heat organic chemicals?
organic chemicals are normally highly flammable and could set on fire with a naked flame
