Organic III Flashcards
Arenes are …
• Aromatic compounds that contain a benzene ring
What is the first evidence that benzene doesn’t have the same structure as cyclohexatriene?
• Enthalpy change of hydrogenation was less exothermic (negative) than expected, indicating benzene is more stable
Is bond breaking endothermic or exothemric?
• Endothermic because energy is required to break the bond
What is the second evidence that benzene has a delocalised ring?
• X ray diffraction experiments showed that all the bond lengths between carbon atoms in benzene are the same
Why is benzene resistant to bromination?
• this is Electrophilic addition
• this would involve breaking up the stable delocalised ring of electrons
• it therefore undergoes Electrophilic substitution reactions
What catalysts can be used in the halogenation of benzene?
FeCl3
FeBr3
AlCl3
AlBr3
amines can be produced by…
this requires…
• the reduction of nitriles by hydrogenation
• reducing agent LiAlH4 and acidic conditions OR hydrogen and nickel catalyst
Amines react with water to form … because…
• an alkaline solution
• lone pair on nitrogen of the amine accept a hydrogen from the water, leaving an OH
amines react with acids to form… because…
• ammonium salt
• the amine accepts a proton and becomes positively charged, bonding with the negative ion left behind from the acid
