1. Hydrocarbons The basis for organic chemistry

2. Organic Compounds Contain C bonded to other elements, commonly H, O, N, S, and halogens Carbon –Can form many different compounds due to its hybrid orbitals –Has intermediate electonegativity, so its most likely to form molecular compounds (Recall: molecular compounds have diverse properties) –Can make single, double, and triple bonds –Can form isomers (same molecular formula but different arrangement of atoms)

3. Types of Hydrocarbons Saturated: Contain the maximum number of hydrogens, single bonds between all carbons Unsaturated: Contain 1 + double or triple bonds

4. Aliphathic Carbons are arranged in chains Cyclic: Carbons are arranged in rings Aromatic: Contain a benzene ring Types of Hydrocarbons

5. Benzene Ring Does not act as 3 single bonds and 3 double bonds It’s 6 identical bonds of intermediate length Due to hybridization (delocalized, shared electrons)

6. Types of Hydrocarbons

7. Naming Alkanes Based off the number of C atoms in the longest chain 1.Count the number of C’s in the longest chain 2.Determine the appropriate root 3.Add the suffix “ane”

8. Hydrocarbon Root Names # of CarbonsRoot Name 1meth- 2eth- 3prop- 4but- 5pent- 6hex- 7hept- 8oct- 9non- 10dec-

9. Structural Shorthand Explicit hydrogens (those required to complete carbon’s valence) are usually left off of drawings of hydrocarbons Line intersections represent carbon atoms C1C1 C1C1 C2C2 C2C2 C3C3 C3C3 C4C4 C4C4

10. Rules for Naming Alkanes (Nomenclature) For a branched hydrocarbon, the longest continuous chain of carbon atoms gives the root name for the hydrocarbon 1 2 3 4 4 carbon chain = butane

11. Naming Branched Alkanes Based off the number of C atoms in the longest chain 1.Count the number of C’s in the longest chain, and number the chain so that the lowest possible number is given to the first branching location. 2.Determine the appropriate root 3.Use the numbered C’s to give the branches a position number add “yl” suffix 4.Add the suffix “ane” if all single bonds

12. Naming Branched Alkanes Important Rules: 1.If there is more than one type of branch, name the branches in alphabetical order (irrespective of any prefix) 2.If there is more than two of the same type of branch, give the branch a position number and prefixes “di”, “tri” “tetra” etc. 3.Put commas between numbers and hyphens between numbers and letters

13. Rules for Naming Alkanes (Nomenclature) When alkane groups appear as substituents, they are named by dropping the -ane and adding -yl. —CH 3 Methyl —CH 2 CH 3 Ethyl —CH 2 CH 2 CH 3 Propyl —CH 2 CH 2 CH 2 CH 3 Butyl Methyl

14. Rules for Naming Alkanes (Nomenclature) The positions of substituent groups are specified by numbering the longest chain of carbon atoms sequentially, starting at the end closest to the branching. Methyl 1 23 4

15. Rules for Naming Alkanes (Nomenclature) The location and name of each substituent are followed by the root alkane name. The substituents are listed in alphabetical order (irrespective of any prefix), and the prefixes di-, tri-, etc. are used to indicate multiple identical substituents. Methyl 1 23 4 Name:2-methylbutane

16. Nomenclature Practice Name this compound Step #1: For a branched hydrocarbon, the longest continuous chain of carbon atoms gives the root name for the hydrocarbon 1 5 24 3 9 6 8 7 9 carbons = nonane

17. Nomenclature Practice Name this compound 1 5 24 3 9 6 8 7 9 carbons = nonane Step #2: When alkane groups appear as substituents, they are named by dropping the -ane and adding -yl. CH 3 = methyl chlorine = chloro

18. Nomenclature Practice Name this compound 1 5 24 3 9 6 8 7 9 carbons = nonane CH 3 = methyl chlorine = chloro Step #3: The positions of substituent groups are specified by numbering the longest chain of carbon atoms sequentially, starting at the end closest to the branching. 19 NOT 91

19. Nomenclature Practice Name this compound 1 5 24 3 9 6 8 7 9 carbons = nonane CH 3 = methyl chlorine = chloro Step #4: The location and name of each substituent are followed by the root alkane name. The substituents are listed in alphabetical order (irrespective of any prefix), and the prefixes di-, tri-, etc. are used to indicate multiple identical substituents. 2-chloro-3,6-dimethylnonane

20. Try the examples on the sheet!

21. Naming Alkenes & Alkynes 1.Count the number of C’s in the longest chain containing the double/triple bond. This is the parent chain, determine the root Number the parent chain so that the double/triple bond has the lowest possible position number 2.Identify the position numbers of branches Same rules as before 3.Write the branches in alphabetical order 4.Write the root, including a number that identifies the position of the double/triple bond 5.Add the suffix “ene” or “yne”

22. Naming Alkenes & Alkynes

23. Cyclic Alkanes Cyclopropane, C 3 H 6 Remember, explicit hydrogens are left out Cyclobutane, C 4 H 8 Cyclopentane, C 5 H 10 Cyclohexane, C 6 H 12 Cycloheptane, C 7 H 14

24. Naming Cyclic Hydrocarbons 1.Number the carbons in the ring, in either direction, so that the multiple bond is between the two lowest numbers, and the branches get the lowest possible position numbers. 2. Identify branches.. Prefixes are the same di, tri, prop etc. and are written alphabetically. 3.The root is –cyclo- plus the name for the number of carbon atoms in the ring. 4.The suffix is –ane for cycloalkanes –ene for cycloalkenes and –yne for cycloalkynes.

25. Naming Cyclic Hydrocarbons

26. Naming Aromatics Contains benzene: Same rules apply If benzene is the parent chain “benzene” suffix If benzene is a branch group “phenyl”

27. Naming Aromatic Hydrocarbons Practice!!

28. Properties of Hydrocarbons Made up of mostly C and H Relatively nonpolar –Low solubility in polar solvents (e.g. water) –Good solvents for other nonpolar molecules Mostly london-dispersion forces (weak) –Low boiling and melting points

29. Reactivity of Hydrocarbons Alkanes are generally less reactive than alkenes or alkynes Aromatic compounds are more reactive than alkanes, but less reactive than alkenes and alkynes. Alkanes < aromatics < alkenes < alkynes

30. Reactions of Hydrocarbons Combustion: –Hydrocarbons burn readily in air to produce carbon dioxide and water. Incomplete Combustion: –Produces carbon and poisonous carbon monoxide. C 3 H 8(g) + 5 O 2(g) --> 3CO 2(g) + H 2 O (g) C 3 H 8(g) + 7/2 O 2(g) --> C (s) + CO (g) CO 2(g) + 4 H 2 O (g)

31. Reactions of Alkanes Single bonds between carbon atoms are difficult to break. (This is why alkanes are relatively unreactive) Can undergo combustion reactions and substitution reactions

32. Reactions of Alkanes Substitution Reactions: Hydrogen atoms may be substituted by a halogen. The product is a halogenated alkane (alkyl halides)

33. Reactions of Alkenes and Alkynes Addition Reactions: Reactions in which a molecule is added to a double or triple bond. No loss of hydrogen atoms from the hydrocarbon

34. Types of Addition reactions

36. Markovnikov’s Rule “The rich get richer” When a hydrogen halide is added to an alkene or alkyne, the hydrogen atom bonds to the carbon atom that already has more hydrogen atoms. Carbon 1 has 2 H’sCarbon 2 has 1 H

37. Reactions of Aromatic Hydrocarbons Less reactive than alkenes and do not undergo addition reactions unless under conditions of extreme temperature or pressure Do undergo substitution reactions (more reactive than alkanes)