Zusammenfassung der Ressource
ketones
- Suffix '-one'
- Parent chain is longest unbranched Carbon chain
- C=O is numbered to show position so the smallest no. is used
- Reacts
- Different to alkenes as O in C=O is more elecronegative than C
- Creates a Dipole as bonded electrons are drawn towards O
- Reduction
- Reduced to secondary alcohols by naBH4
- By neucleophillic Addition
- BH4- ion acts as hydride ion source (:H-)
- Electron defficient C+ in polar C=O gets attacked by :H-
- At same time C=O breaks producing a negatively charged intermediate
- Intermediate donates electron pair to a H from H2O
- This forms a dative covalent bond and a OH-
- The organic addition product is an alcohol
- C-C=O
- Aromatics
- Pehnylethanone
- Production
- Oxidised from secondary alcohols, CANNOT be oxidised further
- Suitable oxidising agent acidified dichromate; H+/Cr2O7 2-
- Tests
- 2,4-DNP (Brady's reagent)
- Yellow or Orange precipitate is formed
- No precipitate formed with COOH or O=C-O
- Precipitate Is impure so is filtred and recrystallised
to produce a pure sample
- Filtred again and left to dry
- Melting point is measured and recorded
- Melting point compared to known samples on a database
- Confirms C=O functional group
- Tollens' Reagent
- No reaction indicates a Ketone is present
- Made by addition of NaOH(aq) to AgNO3(aq) until brown
silver oxide precipitate is formed
- Dilute NH39aq) added until precipitate dissolves