R3.2 Flashcards
(19 cards)
oxidation and reduction
oxidation ⇒ species loses electrons
reduction ⇒ species gains electrons
oxidizing and reducing agents
def+examples
oxidizing agents cause other species to be oxidized, itself becoming reduced (K2Cr2O7, H2SO4, KMnO4)
reducing agents cause other species to be reduced, itself becoming oxidized (LiAlH4 strong ⇒ for all; NaBH4 weak ⇒ not for carboxylic acids)
colour change of KMnO4 when reduced (comp is oxidized)
purple => brown (reduced) => transparent (complete reduction)
colour change of Cr2O7¯ when reduced (comp is oxidized)
not reduced orange, reduced green
acid catalyzed dehydration
def, how, characteristic, catalyst, mechanism
- alcohols → alkenes by removing a molecule of water from adjacent carbons in the carbon chain (the hydroxyl group from one carbon, a hydrogen from a carbon next to the carbon holding the hydroxyl group)
- reaction is reversible (acid catalyzed hydration of alkenes)
- acid is a catalyst
- mechanism: electrophilic addition of water
oxidation of org compounds by elements
oxygen is added or H is removed
which is more acidic - alcohol or carboxylic acid? why?
alcohols < carboxylic acid (since carboxyl group has resonance ⇒ more stable ⇒ stronger acid)
alcohols in acid-base reactions
alcohols lose the hydrogen atom from the hydroxyl group
R-OH + B: → RO¯ + BH+
oxidation of 1° alcohols
products, how to specify them through excess
alcohol → aldehyde → carboxylic acid
oxidation of a primary alcohol to a carboxylic acid requires excess oxidizing agent
to form an aldehyde, the alcohol must be used in excess
oxidation of 2° alcohols
alcohol → ketone
oxidation of 3° alcohols
cannot be oxidized since the carbon bonded to the -OH is bonded to 3 other carbons (cannot form an additional double bond)
phenoxide ion
what is it, created by
benzene ring with O¯ bonded instead of a hydrogen
phenol + OH¯ → phenoxide ion + water (no redox)
oxidation of alkenes
alkene => alcohol
methods of oxidation
- reflux
- distillation
reduction in organic compounds by elements
oxygen is removed or hydrogen is added
reduction reactions
ketone, carb. acid, aldehyde
ketone → secondary alcohol
carboxylic acid → aldehyde
aldehyde → primary alcohol
alkene + H2
product, oxidation/reduction
alkane
reduction
alkyne + H2
product, oxidation/reduction
alkene
alkyne + excess H2 →
product, oxidation/reduction
alkane
