2. Unit 2: Organic Chemistry I. Saturated Hydrocarbons

3. Hydrocarbons fuel compounds Solid: coal Liquids: crude oil Gas: methane Extracted from underground oil fields Created by fossilization of plants billions of years ago

4. Carbonification: special fossilization where carbon is preserved C 6 H 12 O 6 from photosynthesis pressure time absence of Oxygen Hydrocarbons

5. Organic Compounds Must be made of C, H, (hydrocarbons) may also contain O, S, N,P… Simplest: CH 4 methane - main component of natural gas Draw the Lewis Dot structure of methane Draw the Stick Model of methane Remember every stick is one shared electron pair!!!

6. Hydrocarbon Groups Alkanes – single bonds between Carbons (saturated HC) Alkenes – double bonds “ Alkynes – triple bonds “ Naming: Number of Carbons indicated by molecular prefixes followed by –ane, -ene, - yne Note: the first 4 Hydrocarbon prefixes are different from molecular prefixes (historical reasons)

7. Mnemonic for First Four Prefixes First four prefixes Meth- Eth- Prop- But- Monkeys Eat Peeled Bananas

8. Homologous Series of the First 10 Straight Chain Alkanes Methane (meth=1) CH 4 Ethane (eth =2)C 2 H 6 Propane (prop=3)C 3 H 8 Butane (but=4) C 4 H 10 Pentane (pent=5) C 5 H 12 Hexane (hex=6) C 6 H 14 Heptane (hept=7) C 7 H 16 Octane (oct=8) C 8 H 18 Nonane (non=9) C 9 H 20 Decane (dec=10) C 10 H 22

9. Warm-up What is the summative formula for Dodecane (12 Carbon Alkane) Eicosane (20 Carbon Alkane)

10. How to find Alkane Formulas? use: n(CH 2 ) + 2H CH 2 – methylene unit Plus 2 Terminal carbons

11. Ways of Drawing Alkanes 1.Expanded structure (stick model) Shows all Carbons, Hydrogens and bonds Ex: Butane

12. Simplified Structures of Butane 2. Condensed structure A CH 3 -CH 2 -CH 2 -CH 3 3. Condensed structure B CH 3 CH 2 CH 2 CH 3 4. Condensed structure C CH 3 (CH 2 ) 2 CH 3

13. Kekulé or Line Angle Structure Problem: the 4 covalent bonds of Carbon are not arranged in a cross (2D) but in a tetrahedral (3D)

14. 2D drawing vs 3D reality 2-D 3-D

15. Kekulé or Line-Angle Structures Help display 3D-structures Butane in Kekule: Each endpoint, every corner symbolizes a C H are understood Always start drawing in an upward direction

16. Practice What is the name of What is the formula of the structure above? Redraw above structure in condensed A

17. Practice Draw the following alkanes in Kekule and a condensed version of your choice 1.Ethane 2.Pentane 3.Octane

18. Branched Chain Alkanes C 4 H 10 is a summative formula with different possible structures: straight or branched Different structures have different characteristics!

19. Naming of complex organic compounds Governed by IUPAC –International Union of Pure and Applied Chemistry

20. 1. Parent alkane 1.Find the longest line of carbons in any direction C C – C – C – C – C 5 Carbons=pentane

21. 2. Name the Branch 2. A branch is called an alkyl, same prefixes… One carbon side chain is methyl- Two carbon side chain is ethyl- Three …….. C methyl group C – C – C – C – C.

22. Warning There are rarely side chains longer than a propyl! Why? Long side chains are usually part of the parent alkane!

23. 3. Location of the Alkyl Branch Number all carbons of parent chain Choose starting point, so alkyl is attached to lowest number C Name: Carbon number, hyphen, alkyl+parent (one word) C C 5 – C 4 – C 3 – C 2 – C 1 Name: 2-Methylpentane

24. 4. Several Alkyl Branches List alpha, separated by hyphens (b,e,m) Carbon numbering in a way that it give the lowest Ethyl C C C 1 -C 2 -C 3 -C 4 -C 5 -C 6 -C 7 C Methyl 4-Ethyl-3-methylheptane

25. 5. Several identical alkyl sidechain Use di-,tri-, tetra-….prefixes Followed by alkyl (methyl, ethyl, propyl…) C C C-C-C-C-C 2,4-dimethylpentane Name conventions multiple carbon numbers are separated by a comma Carbon number is attached to alkyl by a hyphen Last alkyl and parent alkane are written as one word Prefixes do not change alphabetical order!!!

26. Practice A C C C – C – C – C – C – C - C C 4-Ethyl-3-methylheptane

27. Practice B CH 3 CH 2 CH 3 -CH-CH 2 -CH 2 -CH 3 3-Methylhexane

28. Practice C

29. Practice D

30. Practice E 2,2-dimethylbutane

31. Branched alkyl sidechains 1.Isopropyl – sort according to red letter 2.Secbutyl 3.Tertbutyl 1. 2. 3. parent

32. Cyclical Alkanes Alkanes can form rings Smallest one is Cyclopropane Cyclical alkane formulas have 2 H less than linear due to ringclosure Butane: C 4 H 10 Cyclobutane: C 4 H 8 The most stable alkane rings are cyclopentanes and cyclohexanes Rings larger or smaller are rare (instability)

33. Redraw condensed structures in kekule

34. Cycloalkanes with substituents Cycloalkane is the parent Side chains are attached to lowest carbon number, C1 depends on alpha of sidechain Move clockwise or counterclockwise

35. Haloalkanes Alkanes that have substituents in form of halogens: F, Cl, Br, I Naming: Halogen-ending o: Fluoro, Chloro, Bromo, Iodo…. Sort alpha with other substituents

36. Practice C Cl C Br C – C – C – C – C – C - C C 5-Bromo-2-chloro-4-ethyl-3-methylheptane

37. Alpha List of all Substituents 1.Bromo 2.Butyl 3.Chloro 4.Ethyl 5.Fluoro 6.Iodo 7.Isopropyl 8.Methyl 9.Phenyl 10.Propyl 11.Secbutyl 12.Tertbutyl