How to Identify Organic Compounds
Organic compounds are carbon-based molecules (C–H backbone, often with O, N, S, P, halogens). They’re classified mainly by their functional groups. Each group gives the compound its chemical properties.
1. Hydrocarbons (C + H only)
Simplest organic compounds.
Subgroups:
Alkanes (single bonds) – C–C, C–H only.
Example: Methane (CH₄), Ethane (C₂H₆), Propane (C₃H₈).
Structure: CH₃–CH₃
Alkenes (double bonds) – contain C=C.
Example: Ethene (C₂H₄), Propene (C₃H₆).
Structure: CH₂=CH₂
Alkynes (triple bonds) – contain C≡C.
Example: Ethyne (acetylene, C₂H₂).
Structure: HC≡CH
Aromatic hydrocarbons (benzene ring)
Example: Benzene (C₆H₆), Toluene (C₆H₅CH₃).
2. Alcohols (–OH group)
Contain hydroxyl group bonded to carbon.
Examples:
Methanol (CH₃OH) – toxic, solvent.
Ethanol (C₂H₅OH) – drinking alcohol.
Isopropanol (C₃H₇OH) – rubbing alcohol.
Structure: R–OH
3. Phenols (–OH attached to aromatic ring)
Examples:
Phenol (C₆H₅OH) – antiseptic.
Thymol – in mouthwash.
4. Ethers (R–O–R)
Oxygen linking two carbons.
Examples:
Diethyl ether (CH₃CH₂–O–CH₂CH₃) – early anesthetic.
MTBE – fuel additive.
5. Amines (–NH₂, –NHR, –NR₂)
Derived from ammonia (NH₃).
Examples:
Methylamine (CH₃NH₂).
Aniline (C₆H₅NH₂).
Epinephrine (neurotransmitter).
6. Aldehydes (–CHO)
Carbonyl group at end of chain.
Examples:
Formaldehyde (H–CHO) – preservative.
Acetaldehyde (CH₃CHO) – alcohol metabolism intermediate.
7. Ketones (C=O in middle of chain)
Examples:
Acetone (CH₃COCH₃) – nail polish remover.
Butanone (CH₃COCH₂CH₃).
8. Carboxylic Acids (–COOH)
Acidic organic group.
Examples:
Formic acid (HCOOH) – ant stings.
Acetic acid (CH₃COOH) – vinegar.
Citric acid (C₆H₈O₇) – citrus fruits.
9. Esters (R–COO–R)
Formed from acid + alcohol. Sweet/fruity smells.
Examples:
Ethyl acetate (CH₃COOCH₂CH₃) – solvent.
Isoamyl acetate – banana smell
10. Amides (R–CONH₂, R–CONHR, R–CONR₂)
Found in proteins (peptide bonds).
Examples:
Acetamide (CH₃CONH₂).
Urea – major component in urine.
11. Nitriles (–C≡N)
Carbon triple-bonded to nitrogen.
Examples:
Acetonitrile (CH₃CN) – solvent.
Benzonitrile (C₆H₅CN).
12. Halogenated Compounds (R–X, X = F, Cl, Br, I)
Examples:
Chloroform (CHCl₃) – anesthetic.
Dichloromethane (CH₂Cl₂) – solvent.
Freons (CFCs).
13. Biological Macromolecules
Built from organic groups above.
Carbohydrates – glucose (C₆H₁₂O₆), sucrose.
Lipids – triglycerides (glycerol + 3 fatty acids).
Proteins – polymers of amino acids (amines + carboxylic acids).
Nucleic Acids – DNA/RNA (sugars, bases, phosphate).
Tips for Identifying Compounds
Look for functional groups: OH, COOH, NH₂, C=O, C≡N.
Name based on parent chain + suffix:
–ane (alkane), –ene (alkene), –yne (alkyne).
–ol (alcohol), –al (aldehyde), –one (ketone), –oic acid (carboxylic acid).
Examples in real life: Medicines, fuels, plastics, food molecules.
No comments:
Post a Comment