Chapter 12 Organic Chemistry: The Infinite Variety of Carbon Compounds

1. Chapter 12 Organic Chemistry: The Infinite Variety of Carbon Compounds

2. Organic Chemistry • Chemistry of carbon-containing compounds • Most of these come from living things • Not necessarily the case • ~30 million chemical compounds known • 95% are compounds made of carbon Chapter 9

3. Carbon • Able to bond strongly to other carbon atoms • Forms long chains • Very few other atoms can form short chains, let alone long chains • Capable of forming ring structures • Bonds strongly to other elements • In particular, H, O, and N Chapter 9

4. Hydrocarbons • Made of carbon and hydrogen • Several classes • Alkanes • Contain only single bonds • Saturated hydrocarbons • Each C atom bonded to maximum number of H atoms Chapter 9

5. Alkanes • Chemical formula CnH2n+2 n = 1, 2, 3, … • CH4, methane, simplest one • C2H6, ethane • All have –ane ending • Follow a pattern Chapter 9

6. Condensed structural formulas • Show how many hydrogens are attached to each carbon CH3-CH3 for ethane • Structural formulas show how atoms are bonded together Chapter 9

7. Isomerism • Isomers: compounds with same molecular formula but different structural formulas • Differences in structure may give rise to differences in chemical and physical properties Chapter 9

8. Number of possible isomers increases rapidly with the number of carbons • C30H62 – >4 billion possible isomers Chapter 9

9. Chapter 9

10. Properties of Alkanes • Main property: will burn Chapter 9

11. Cyclic Hydrocarbons • Carbon atom chains in form of rings • Can be represented by structural formulas or symbolic representations Chapter 9

12. Unsaturated Hydrocarbons • Can have more hydrogen atoms added • Very important in biological systems • Alkene: hydrocarbon that contains one or more carbon-to-carbon double bonds • General formula of CnHn • Simplest: ethylene, C2H4 Chapter 9

13. Alkyne: hydrocarbon that contains one or more carbon-to-carbon triple bonds • General formula of CnH2n–2 • Simplest: acetylene, C2H2 Chapter 9

14. Properties of Alkenes and Alkynes • Similar physical properties to alkanes • Undergo more reactions than alkanes • Addition reaction: add compounds across double bond • Importantly, they can form polymers Chapter 9

15. Aromatic Hydrocarbons • Contain double or triple bonds, but do not show the same reactivity as other unsaturated hydrocarbons • Benzene: C6H6 • Used mainly as solvents Chapter 9

16. Chlorinated Hydrocarbons • Add Cl to hydrocarbons • Increase reactivity of alkanes • Dissolve fats, oils, and greases • Useful for dry cleaning • Tend to accumulate in fatty tissues • If toxic, this will be a problem Chapter 9

17. Chlorofluorocarbons and Fluorocarbons • Tend to be either liquids or gases • Completely inert • Except in upper atmosphere • O2 soluble in fluorinated compounds • Temporary substitute for hemoglobin Chapter 9

18. Functional Groups • Group of atoms that gives a family of organic compounds its characteristic chemical and physical properties • Alkyl group: derived from alkane by removing a H • R stands for alkyl group in general Chapter 9

19. Chapter 9

20. Alcohol Family • –OH group • Replace -e with -ol • CH3OH, methanol, simplest • Produced industrially • Mainly a chemical intermediate Chapter 9

21. C2H5OH, ethanol • Made industrially and by fermentation • Industrially produced alcohol has noxious substances added • Small, simple alcohols tend to be toxic Chapter 9

22. Multifunctional Alcohols • Several common alcohols have more than one –OH group • Ethylene glycol: main ingredient in antifreeze • Glycerol: used in lotions • Ingredent in some explosives Chapter 9

23. Phenol • –OH group on benzene ring • Different chemical properties than other alcohols • Behaves more like an acid • First antiseptic • Also causes skin irritation Chapter 9

24. Ethers • Two alkyl groups attached to same O • Example CH3CH2-O-CH2CH3 • Used mainly as solvent • Little chemical reactivity • Insoluble in water • Highly flammable Chapter 9

25. Chapter 9

26. Aldehydes and Ketones • Both contain carbonyl group (C=O) • Aldehyde: R-CHO • Ketone: R-CO-R’ Chapter 9

27. Common Aldehydes • Change -e ending to -al • Produced by oxidation of alcohols • Formaldehyde – used as a preservative • Larger ones used as fragrances • Benzaldehyde – flavor in maraschino cherries Chapter 9

28. Common Ketones • Change -e ending to -one • Acetone most common ketone • Used primarily as a solvent • Produced by oxidation of alcohols Chapter 9

29. Chapter 9

30. Carboxylic Acid • Contains C=O and –OH group on same carbon • Change -e to -oicacid • Acetic acid: acid in vinegar Chapter 9

31. Chapter 9

32. Esters • Derived from carboxylic acids and alcohols • Tend to be fragrant • Methyl butyrate apple • Ethyl butyrate pineapple • Ethyl formate rum • Methyl salicylate wintergreen Chapter 9

33. Amines • Contain N • May have 1, 2, or 3 alkyl or aromatic groups • Most biological amines are amino acids • Building blocks of proteins Chapter 9

34. Amides • N bonded directly to carbonyl group • Linkage that holds proteins together Chapter 9

35. Heterocyclic Compounds • Ring compounds that have something other than C in the ring • Occur in plants • Alkaloids: basic in solution • Examples: caffeine, morphine, cocaine • Form basic structure of DNA Chapter 9