3. Organic Chemistry Organic Chemistry involves the study of carbon based compounds Organic Chemistry involves the study of carbon based compounds Almost all compounds utilized by living organisms involve carbon hence the name “Organic” chemistry Almost all compounds utilized by living organisms involve carbon hence the name “Organic” chemistry What are some examples of Organic Based compounds? What are some examples of Organic Based compounds? Petrochemicals Petrochemicals Dyes Dyes

4. Why so many C compounds? Carbon atoms can bond with other carbon atoms in chains, rings, and networks. Carbon atoms can bond with other carbon atoms in chains, rings, and networks. These bonds are covalent. These bonds are covalent. Carbon has 4 unpaired electrons & can form 4 covalent bonds. Carbon has 4 unpaired electrons & can form 4 covalent bonds. C C H can only form 1 bond Halogens only form 1 bond O, S can only form 2 N, P can only form 3

5. Condensed Structural Formulas These formulas show type & # of atoms as well as some information regarding what atoms are bonded to what atoms. They do not show bonds Ex: CH 3 CH 2 CH 2 CH 3

6. Molecular Formulas These formulas show type & # of atoms but not necessarily any other information These formulas show type & # of atoms but not necessarily any other information Ex: CH 3 CH 2 CH 2 CH 3 becomes C 4 H 10

7. Terms: Saturated: organic compounds containing only single bonds (carbon bonded to 4 atoms) Unsaturated: organic compounds containing one or more double or triple bonds.

8. More Vocabulary Terms: Hydrocarbons: organic compounds containing only carbon and hydrogen. Hydrocarbons: organic compounds containing only carbon and hydrogen. Straight chain: All C bonded to only 2 other C’s Ex: H 3 c-cH 2 -cH 2 -cH 2 -cH 2 -cH 2 -cH 3 Straight chain: All C bonded to only 2 other C’s Ex: H 3 c-cH 2 -cH 2 -cH 2 -cH 2 -cH 2 -cH 3 Branched: One or more C bonded to 3 or 4 other C’s Branched: One or more C bonded to 3 or 4 other C’s Ex: Ex: CH 3 -CH-C H 2 -C H -CH 3 | | CH 3 CH 3

9. Primary Categories of Hydrocarbons Straight Chain or Branched (n = # of C atoms) Alkanes (Single Bonds) [H = 2n +2] Alkanes (Single Bonds) [H = 2n +2] CH 3 CH 2 CH 2 CH 3 CH 3 CH 2 CH 2 CH 3 Alkenes (Double Bond) [H = 2n] Alkenes (Double Bond) [H = 2n] CH 3 CH 2 CH=CH 2 CH 3 CH 2 CH=CH 2 Alkynes (Triple Bond) [H = 2n – 2] Alkynes (Triple Bond) [H = 2n – 2] CH 3 CH 2 C CH CH 3 CH 2 C CH

10. Alkanes A homologous series of saturated hydrocarbons. A homologous series of saturated hydrocarbons. Homologous meaning that the compounds are strucutres differing by the same repeating unit (-CH 2 -) Homologous meaning that the compounds are strucutres differing by the same repeating unit (-CH 2 -)

11. Prefix # of C atoms Meth Meth1 Eth2 Prop3 But4 Pent5 Hex6 Hept7 Oct8 Non9 Dec10

12. Problem: Draw the structural formula for pentane. Problem: Name CH 3 -CH 2 -CH 2 -CH 3 Practice Problem: What’s the formula for the alkane with 22 carbon

13. Rules for Naming Alkanes 1. Identify the longest continuous chain of carbons. Count the # of C atoms. This is called the root. 2. Find the suffix. Single bonds –ane (there will be others)

14. 3. Give the position numbers of the branches. Number the main chain starting from the end that gives the lowest number to the first location at which the branching occurs

15. 4. Find the prefix Name each branch depending on the number of carbons involved. Each branch will have a position number. These groups will end in “yl” If more than one branch is present, write the names of the branches in alphabetical order (ex methyl or ethyl) not the multiplying prefix (di, tri, tetra, etc) If more than one branch is present, write the names of the branches in alphabetical order (ex methyl or ethyl) not the multiplying prefix (di, tri, tetra, etc)

16. If there is more than one type of the same branch you must use multiplying prefixes to indicate how many are present If there is more than one type of the same branch you must use multiplying prefixes to indicate how many are present Hyphens separate words from numbers Hyphens separate words from numbers Commas separate numbers Commas separate numbers 5. Put the name together prefix + root + suffix

18. Ex. Name

19. Draw the following: Draw the following: (a) 2 – methylpropane (b) 3 – ethyl – 4 -methylnonane (c) 2,2 – dimethylpropane (d) 2,3,4 – trimethyldecane

20. Work on Naming Alkane Practice Sheet Naming Alkane Practice Sheet Read pg 331 - 339 Read pg 331 - 339

22. Naming branched-chain alkanes Find the longest continuous chain or backbone of C atoms. c-c-c-c-c-c-c-c-c-c c c What’s the longest chain? c The base name is derived from the number of C’s in the longest chain. 10 carbons would be decane

23. Naming branched-chain alkanes Branches are added as a prefix and are named by counting the number of C atoms. Branches are added as a prefix and are named by counting the number of C atoms. The “branch” alkane name ends in “yl.” The “branch” alkane name ends in “yl.” Methyl CH 3 — Ethyl CH 3 CH 2 – Propyl CH 3 CH 2 CH 2 – Butyl CH 3 CH 2 CH 2 CH 2 – c-c-c-c-c-c-c-c-c-c c c c c c

24. Naming branched-chain alkanes The location of the branch (or substituent group) is shown by assigning # to the C’s in the backbone. The location of the branch (or substituent group) is shown by assigning # to the C’s in the backbone. Number from the end that gives the lowest # for the first branch. Number from the end that gives the lowest # for the first branch. Substituent groups (branches) are listed alphabetically Substituent groups (branches) are listed alphabetically 7-ethyl-3-methyldecane c-c-c-c-c-c-c-c-c-c c c c c c 1 2 3 4 5 6 7 8 9 10

25. There may be more than one of the same type of branch. There may be more than one of the same type of branch. Use di, tri, tetra etc. for 2, 3, and 4 Use di, tri, tetra etc. for 2, 3, and 4 does not change the alphabetical order. Using these prefixes for multiple branches of the same type does not change the alphabetical order. Number the locations and separate the # with a comma & Number the locations and separate the # with a comma & separate the last # from the name with a dash

26. H H–C–H H H–C–C–C–H H H-C-H | H Longest continuous chain has 3 carbon atoms – propane. 2 branches each have 1 carbon – dimethyl. Branches have to be at C-2. WHY?? (Only give the number if necessary.) Ex:

27. Longest continuous chain has 4 carbon atoms – butane. 2 branches each have 1 carbon – dimethyl. Branches are at C-2. WHY?? 2,2-dimethylbutane CH 3 | H 3 C-C-CH 2 -CH 3 | CH 3 Name this compound

28. H H – C – H H H H H – C – C – C – C – H H H H–C–H H–C–H H H Longest continuous chain has 6 carbon atoms: hexane Branch is 1 carbon long: methyl Branch is located at C-3 3-methylhexane Name this compound:

29. Ex. Name

30. Draw the following: Draw the following: (a) 2 – methylpropane (b) 3 – ethyl – 4 -methylnonane (c) 2,3,4 – trimethyldecane

31. More Naming Problems

32. Problems: Draw the following: Draw the following: (a) 2 – methylpropane (b) 3 – ethyl – 4 - methylnonane (c) 2,2 – dimethylpropane (d) 2,3,4 – trimethyldecane What name does this compound have?

33. Primary Categories of Hydrocarbons Cyclic Cyclic Aromatics (Benzene related compounds) Aromatics (Benzene related compounds) Non-aromatic Non-aromatic Cyclopropane Cyclobutane Cyclopentane Cyclohexane C 3 H 6 C 4 H 8 C 5 H 10 C 6 H 12 C6H6C6H6 The simplest aromatic Hydrocarbon (alternating Double bonds) Cyclopropane is the Simples cyclic hydrocarbon

34. Isomers Compounds with the same molecular formula but different structural arrangement are known as structural isomers. Compounds with the same molecular formula but different structural arrangement are known as structural isomers. The more C atoms there are in the formula, the more structural isomers there will be. The more C atoms there are in the formula, the more structural isomers there will be. 4C (1) 5C(3)6C(5)8C(18) C20(>303,000)

35. Structural Isomers In order to determine if something is an isomer determine the molecular formula In order to determine if something is an isomer determine the molecular formula To the right we have To the right we have pentane (Top) pentane (Top) 2 – methyl butane 2 – methyl butane What is the mol. Formula for each? Are they What is the mol. Formula for each? Are they structural isomers? structural isomers? C 5 H 12 – Yes, they Are isomers

36. Recall that the members of the group of alkanes Forms a homologous series and each member of This series differs from the last by 1 –CH 2 - unit When we draw the structural formulas of the 1 st three members of this group there is only one way each can be drawn. CH 4 CH 3 -CH 3 CH 3 -CH 2 -CH 3 Drawing simple alkanes

37. Branched-chain alkanes Beginning with butane, C 4 H 10, there is more than 1 way to arrange the atoms besides one carbon after another. Beginning with butane, C 4 H 10, there is more than 1 way to arrange the atoms besides one carbon after another. CH 3 -CH 2 -CH 2 -CH 3 & CH 3 | CH 3 -CH-CH 3

38. Branched-chain alkanes In both butane structures we have the same # and kind of atoms namely, C 4 H 10 In both butane structures we have the same # and kind of atoms namely, C 4 H 10 The general formula for each is also C n H 2n+2 so each represents the alkane “Butane” The general formula for each is also C n H 2n+2 so each represents the alkane “Butane” Yet there is a difference. The difference lies in what atoms are joined to what atoms Yet there is a difference. The difference lies in what atoms are joined to what atoms CH 3 -CH 2 -CH 2 -CH 3 & CH 3 *| CH 3 -CH-CH 3 * Are there any other ways to draw 4 carbon butane? No

39. Note that what we have drawn for butane represents real structural changes and not just apparent changes as a result of the rotation of a C-C single bond. Let’s look a pentane to see what we mean by this. Rotation of this bond Leads to this configuration Of pentane And rotation of this Bond leads to this All of these structures however represent the SAME molecule!

40. Pentane Isomers To find new structural isomers of the straight chain alkanes we need to move the point of attachment of the various carbon atoms. Straight chain isomer Remember, carbon must have 4 bonds. No more, No less! So how many structural Isomers does pentane Have?