Organic Organische Funktionen

Each organic function is defined by a specific functional group — the set of atoms that gives the molecule its characteristic chemical behavior. Pick a function below to see the definition, general formula, naming rule, properties, applications and worked examples.

Schnell erkennen

Suche nach dem wiederkehrenden Strukturmuster. C=C steht für ein Alken; C≡C für ein Alkin; C=O am Kettenende für ein Aldehyd und C=O zwischen Kohlenstoffen für ein Keton. Heteroatome helfen ebenfalls: -OH deutet auf einen Alkohol hin, -COOH eine Carbonsäure, -COO- einen Ester, -O- einen Ether, -NH₂ ein Amin, and -CONH₂ ein Amid.

Vergleichsübersicht

A molecular formula can be shared by different compounds. What defines the function is connectivity: which atoms are bonded, and what type of bond connects them.

FunktionCharacteristic groupUseful behavior clueKnown example
Alkanesingle C–Cnonpolar and relatively unreactivepropane
AlkeneC=Caddition and polymerizationethene
AlkyneC≡Clinear geometry and additionethyne
AlcoholR–OHhydrogen bondingethanol
AldehydeR–CHOterminal carbonyl and easy oxidationethanal
KetoneR–CO–R'internal carbonyl and solvent behaviorpropanone
Carboxylic acidR–COOHacidity and hydrogen-bonded dimersethanoic acid
EsterR–COO–R'hydrolysis and characteristic aromasethyl ethanoate
EtherR–O–R'accepts, but does not donate, Hethoxyethane
AmineR–NH₂ / R₂NH / R₃Nbasicity and protonationmethanamine
AmideR–CONH₂resonance and peptide bondsethanamide
HalideR–Xsubstitution and eliminationchloromethane

Warum die Funktion wichtig ist

Die funktionelle Gruppe verändert Polarität, Siedepunkt, Löslichkeit, Säuregrad, Basizität und Reaktivität. That is why ethanol and ethyl ethanoate, even though both contain carbon, hydrogen, and oxygen, differ greatly in odor, miscibility, and reactions.

Lernweg
  1. Identify the functional group in the structure.
  2. Compare its polarity and intermolecular interactions.
  3. Learn the suffix when it is principal and prefixes when it is not.
  4. Test a structure in the simulator and inspect the name breakdown.

Prioritätsreihenfolge (IUPAC)

When a molecule has more than one functional group, only one becomes the suffix (the "main group") — the others become prefixes. The priority order, from highest to lowest, is:

  1. Carboxylic acids
  2. Esters
  3. Amides
  4. Nitriles
  5. Aldehydes
  6. Ketones
  7. Alcohols / Phenols
  8. Amines
  9. Ethers

Sulfonic acids and acyl halides are also important acid derivatives. Simple halides are always prefixes, never suffixes. See the full detail in IUPAC-Nomenklatur.

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