1. Organic Chemistry

2. Organic Chemistry – the study of compounds containing carbon
Organic chemistry was thought to be the study of products made from organisms
Chemists obtain organic compounds in two principal ways:
isolation from nature
synthesis in the laboratory.
 Compounds made in the laboratory are identical in both chemical and physical properties to those in nature.

3. 85% of all known compounds are organic compounds.
Why Organic Chemistry?
Organic compounds are found everywhere around us (foods, flavors, fragrances, medicines, toiletries, cosmetics, plastic, paints, our body, and etc.).
85% of all known compounds are organic compounds.
Chemists have discovered or synthesized more than 10 million organic compounds.

4. Typical properties of organic compounds
They contain carbon atom.
They have covalent bonds.
They have low boiling point and melting point.
They are flammable (almost all burn).
They are soluble in nonpolar compounds.
They can be gas, liquid or solid.
Can form large molecules.

5. It is important to know:
•Carbon: normally forms 4 covalent bonds and has no unshared pairs of electrons.
•Hydrogen: forms 1 covalent bond and no unshared pairs of electrons.
•Nitrogen: normally forms 3 covalent bonds and has one unshared pair of electrons.
•Oxygen: normally forms 2 covalent bonds and has two unshared pairs of electrons.
•Halogen: normally forms 1 covalent bond and has three unshared pairs of electrons.

6. Hydrocarbons are the large family of organic compounds and they contain only carbon and hydrogen atoms. Hydrocarbons are divided into the two groups: 1. Saturated hydrocarbon: a hydrocarbon that contains only carbon-carbon single bonds (alkanes) 2. Unsaturated hydrocarbon: a hydrocarbon that contains one or more carbon-carbon double bonds, triple bonds, or benzene rings.

7. Alkanes
Alkanes are saturated hydrocarbon (they have only carbon-carbon single bonds).
The molecular formula of this group is CnH2n+2 (n is number of carbon atoms).
Chemical properties of alkanes:
in general, they have low reactivity.

8. Physical properties of alkanes
They are nonpolar.
They are insoluble in water.
They have a lower density than water.
They have low boiling point and melting point.
They can be gas (with 1 to 4 carbon atoms), liquid (with 5 to 17 carbon atoms) or solid (with 18 or more carbon atoms).

9.  The boiling point and the melting point of alkanes increase by increasing the number of carbon atoms.
The boiling point and the melting point of alkanes decrease by increasing the number of branches.

10. IUPAC Names Name # carbons Structural Formula Methane 1 CH4
Ethane 2 CH3CH3
Propane 3 CH3CH2CH3
Butane 4 CH3CH2CH2CH3
Pentane 5 CH3CH2CH2CH2CH3
The names of organic compounds are determined by the IUPAC rules (International Union of Pure and Applied Chemistry). The stem of the name states the number of carbon atoms in the carbon chain of the compounds. The suffix, in this case –ane, indicates the alkane family.

11. IUPAC NAMES Name # carbons Structural Formula
Hexane CH3CH2CH2CH2CH2CH3
Heptane CH3CH2CH2CH2CH2CH2CH3
Octane CH3CH2CH2CH2CH2CH2CH2CH3
Nonane CH3 CH2 CH2CH2CH2CH2CH2CH2CH3
Decane CH3CH2CH2CH2CH2CH2CH2CH2CH2CH3

12. Mnemonic for first four prefixes
Monkeys
Eat
Peeled
Bananas
First four prefixes
Meth-
Eth-
Prop-
But-

13. Complete Structural Formulas
Show the bonds between each of the atoms
H H
 
H  C  H H C H
H H
CH4 , methane
In methane, CH4 the four valence electrons of carbon are shared with the single electrons of four hydrogen (H) atoms. Each pair of electrons is a single bond, which can be drawn as a line. When a structure is drawn to show each bond, it is called a complete structural formula.

14. More Alkanes H H Condensed Structural Formulas H C C H CH3 CH3
H H Ethane
H H H
H C C C H CH3 CH2 CH3
H H H Propane
The complete structural formula for ethane shows the single bonds between two carbon atoms and six H atoms. The complete structural formula of propane shows the 3-carbon chain with single bonds to the attached H atoms. To write a condensed structural formula, the H atoms are written as a group next to their respective C atoms.

15. Learning Check A. What is the condensed formula for H H H H
H C C C C H
B. What is its molecular formula?
C. What is its name?

16. Naming the unbranched alkanes
The IUPAC name consists of two parts:
A prefix that shows the number of carbon atoms (meth-, eth-, prop-, but-, pent-, hex-, hept-, oct-, non- and dec-).
2. The suffix “-ane”.
CH4 Methane C2H6 Ethane
C3H8 Propane C4H10 Butane

18. Substituent group: they are the branches in the organic compounds.
They are derived from an alkane by removal of a hydrogen atom.
They are named by dropping the
“-ane” from the name of the alkane and adding the suffix “-yl” (we call them alkyl group).
CH3- Methyl C2H5- Ethyl C3H7- Propyl
Note: some substituents are made from other elements:
  -F Fluoro -Cl Chloro

19. Naming branched alkanes
Write the alkane name of the longest continuous chain of carbon atoms.
Number carbon atoms starting from the end nearest substituent.
Give the location and name of each substituent (alphabetical order) as a prefix to the name of the main chain.

20. Naming side chains Names are made up of: side chains, root3
Names are made up of: side chains, root
2,3-dimethylpentane
Root is the longest possible HC chain
Must contain multiple bonds if present
Add -yl to get name of side chain

21. Naming side chains 3-methylhexane 4-ethyl-2,3-dimethylheptane
5-ethyl-2,4,6-trimethyloctane

22. Alkyl branches
Branches on carbon chains
CH3 methyl
CH3CH2 ethyl

23. Branched Alkanes CH3 CH3CHCH3 methyl groups CH3 CH3 CH3CHCH2CHCH3
In the structural formula of an alkane, the alkyl group is typically attached vertically above or below the carbon chain.

24. Naming Branched Alkanes
CH methyl branch
CH3CH2CH2CHCH2CH3
Count
A branched-chain alkane is named by indicating the attached groups on the longest carbon chain. In this example, the longest carbon chain has 6 carbon atoms.

25. Naming Branched Alkanes
CH methyl branch
CH3CH2CH2CHCH2CH3
Count
3-Methylhexane
on third C CH six carbon chain
group
The chain is numbered to give the side group or methyl group a location on carbon 3 in the chain.

26. Naming Summary 1. Count the C’s in the longest chain
2. Name each attached group
3 Count the longest carbon chain to give the first attached group the smallest number
4. Name and locate each group

27. Learning Check A. CH3 CH3 CH3CHCH2CHCH3 B. CH3 CH3 CH3CH2CHCH2CCH2CH3

28. Solution A. CH3 CH3 CH3CHCH2CHCH3 2,4-dimethylpentane B. CH3 CH3
CH3CH2CHCH2CCH2CH3
CH ,3,5-trimethylheptane

29. Learning Check Write a condensed structure for A. 3,4-dimethylheptane
B. 2,2-dimethyloctane

30. Solution A. 3,4-dimethylheptane CH3 CH3CH2CHCHCH2CH2CH3 CH3
2,2-dimethyloctane CH3
CH3CCH2CH2CH2CH2CH2CH3

31. Isomers Same molecular formula Same number and types of atoms
Different arrangement of atoms
Structural isomers are compounds that have the same molecular formula with different arrangements of the atoms.

32. Isomers Isomers: compounds with the
same molecular formula but a different
connectivity of their atoms.
Cycloalkane: a saturated hydrogen that contains carbon atoms bonded to form a ring. A hydrocarbon that contains carbon atoms joined to form a ring is called a cyclic hydrocarbon.

33. Examples of Isomers CH3 The formula C4H10 has two different structures
CH3CH2CH2CH3 CH3CHCH3
Butane methylpropane
When a CH3 is used to form a branch, it makes a new isomer of C4H10.

34. Learning Check
Write 3 isomers of C5H12 and name each.

35. Solution CH3 CH3CH2CH2CH2CH3 pentane CH3CHCH2CH3 2-methylbutane
CH3CCH3 2,2-dimethylpropane

36. Alkene
An unsaturated hydrocarbon that contains a carbon-carbon double bond.
The molecular formula of this group is CnH2n (n is number of carbon atoms).
They have less hydrogen atoms than alkanes.
C2H4 CH2=CH4 C3H6 CH2=CH-CH3

37. Numbering carbons 1-pentene Q- draw pentene A- Where’s the bond?
We number C atoms
Thus, naming compounds with multiple bonds is more complex than previously indicated
Always give double bond the lowest number
Q - Name these
C2H4
2-butene
Ethene
3-nonyne

38. Naming side chains Be sure multiple bond is in your longest chain
Rule 1: choose the correct ending
ene

39. Naming side chains
ethyl
methyl
methyl
2-ethyl-4,4-dimethyl 1-hexene

40. Naming side chains Name the structures below 3-ethyl-2-methylpentane
3-ethyl-1,5,5-trimethylcyclohexene

41. Alkynes
An unsaturated hydrocarbon that contains a carbon-carbon triple bond.
The molecular formula of this group is CnH2n-2 (n is number of carbon atoms).
They have less hydrogen atoms than alkanes and alkenes.

42. Naming unbranched alkenes and alkynes
Use the IUPAC names for alkanes.
For alkenes, we replace the suffix “-ane” of alkanes by “-ene”.
For alkynes, we replace the suffix “-ane” of alkanes by “-yne”.

44. Naming branched alkenes and alkynes
Name the longest carbon chain with a double or triple bond.
Number the carbon chain starting from the end nearest a double or triple bond.
Give the location and name of each substituent (alphabetical order) as a prefix to the name.

45. Aromatic Compounds
Aromatic compounds: contains one or more benzene rings.
Benzene: is an unsaturated compound and it has the molecular formula C6H6 (six carbon atoms and six hydrogen atoms).
Benzene has a ring structure
Benzene as a branch is named
phenyl.

46. Naming aromatic compounds
1. When one substituent group is attached to benzene, we write the name of group in front of benzene.

47. Naming aromatic compounds
2. When two or more substituents are attached to benzene, the ring is numbered to the lower numbers to the side groups.

48. Naming: common vs. IUPAC
Common names used in the 1800’s are still used for some compounds today:
Acetone
Formic acid
Acetylene
The International Union of Pure and Applied Chemistry (IUPAC) was established in 1900s
Frequent revisions to nomenclature
Systematic method allows an infinite number of compounds to be named given a few rules

49. Drawing structures: it’s all good
2-butene
CH3CH=CHCH3

50. Functional groups
alcohol
alkene
ester
ketone
carboxylic acid

51. carboxylic acid
ester
ether
aldehyde
amine
nitrile

53. Alcohols OH
CH3-CH2-CH2OH
Propanol

54. Functional Groups aldehyde O CH3CH2CH2C butanal H O ketone
CH3CH2CCH2CH3 O
ketone
3-pentanone
Diethyl ketone

55. Functional Groups CH3 carboxylic acid O CH3CHCH2COH
CH3
carboxylic acid
3-methylbutanoic acid
CH3CH2C O
OCH2CH3
ester
ethylpropanoate
diethyl ester

56. Functional Groups
ether
CH3CH2
-O-CH2CH3
Diethyl ether
ethoxyethane

57. Polymerization
Polymers are huge molecules made by combining small molecules called monomers
Example: Compounds with double bonds add on to each other, end-to-end forming cross-linked chains
CH2 =CH2 + CH2 =CH2  -CH2-CH2-CH2-CH2-