organic nomenclature alkanes

Organic NomenclatureAlkanesSWBAT: Name alkanes with alkyl groups

Organic Chemistry The study of the structure,

properties, composition, reactions, and preparation (synthesis) of carbon-based compounds, hydrocarbons and their derivatives

Organic Molecules Organic molecules are compounds

consisting of nonmetals (hydrogen, nitrogen, oxygen, the halogens, phosphorus, silicon and sulfur) with carbon

Due to carbon’s hybrid bonding orbitals, organic molecules have a variety of configurations

The types of atoms bonded to the carbon atoms will ultimately determine function and properties of the compound

Organic vs. InorganicGeneral Comparison

Organic Compounds Mostly covalent

bonding Low boiling pt Low melting pt High flammability Most are nonpolar Not soluble in water

unless a polar group is present

Do not conduct electricity

Inorganic Compounds Many ionic, some

covalent High boiling pt High melting pt Low flammability Most are ionic or

polar covalent Most are soluble in

water unless nonpolar

Conduct electricity

Hydrocarbons A hydrocarbon chain is a series of

carbons bonded together with numerous hydrogen's attached

Includes Alkanes, Alkenes, Alkynes and Cyclical HC

Use certain prefixes for naming to indicate chain length

Alkane Formulas and Names Strings, branches of carbons with

single bonds between C Essentially many CH4 reacted

together Formula rules: CnHn+2 CH2 – methylene unit Names: Prefixes indicate # of C

followed by -ane

Homologous series of the first 12 linear alkanes Methane (meth=1) CH4 Ethane (eth =2) C2H6 Propane (prop=3) C3H8 Butane (but=4) C4H10 Pentane (pent=5) C5H12 Hexane (hex=6) C6H14 Heptane (hept=7) C7H16 Octane (oct=8) C8H18 Nonane (non=9) C9H20 Decane (dec=10) C10H22 Undecane (undec = 11) C11H24 Dodecane (dodec= 12) C12H26

1-10 Alkane Prefix QuizJust the prefix…not the -ane

1.CH42.C2H63.C3H84.C4H10 5.C5H12

6.C6H14 7.C7H168.C8H18 9.C9H20 10.C10H22

Mnemonic for First 8 Prefixes Mrs. Edwards Plays Basketball,

Please Hold Her Overcoat Methane CH4

Ethane C2H6 Propane C3H8 Butane C4H10 Pentane C5H12  Hexane C6H14 Heptane C7H16 Octane C8H18

Alkane Naming and Drawing1. Expanded structure

1. Make string of carbons (prefix= # of C)

Ex: Butane (but=4)

Butane2. Condensed structure A

CH3-CH2-CH2-CH3

3. Condensed structure BCH3CH2CH2CH3

4. Condensed structure CCH3(CH2)2CH3

Butane5. Carbon skeleton: C-C-C-C

*all H are understood

6. Kekulé or Line-angle formula(most reduced form)

• Each endpoint, every corner symbolizes a C

• H are understood

Alkanes

methane

CH4

hexane

C6H14

ethane

C2H6

heptane

C7H16

propane

C3H8

octane

C8H18

butane C4H10

nonane

C9H20

pentane

C5H12

decane

C10H22

Alkyl Groups Substituent – element or group of

elements that branch off parent chain (replace a H)

methyl group

ethyl group

propyl group

Alkyl Groups isopropyl

butyl groups butyl secbutyl tertbutyl isobutyl

Only iso- is alphabetized,tert, sec are not.

Haloalkanes Haloalkanes have a halogen that has

replaced a hydrogen The halogens are substituent groups

treated the same as the alkyl groups. Alpha without prefixes

F = fluoroCl = chloroBr = bromoI = iodo

Rules to Naming Hydrocarbon Chains

1. Number the longest continuous chain of carbons

1. Carbons attached to double/triple bonds receive the smallest number possible

2. If no double/triple bonds are present, carbons with groups attached, receive the smallest number possible

2. Use prefixes for repeating groupsdi, tri, tetra, penta, hexa, ….

3. Alphabetize groups without prefixes4. All lowercase, commas between numbers,

dashes between numbers and words5. Use appropriate ending

ane, ene, yne or functional group ending

Find The Longest Continuous Chain of Carbons

Number the Carbons so that the groups receive the smallest number possible

Use prefixes with same multiple substituent groups

7 – ethyl – 3,5 - dimethyl – 6 - tertbutylundecane

Naming Hydrocarbon Chains

Naming Hydrocarbon Chains

Naming Hydrocarbon Chains

If more than one type of substituent group, alpha. the groups without prefixes

5 – secbutyl - 3,6 – dimethylnonane

4 – tertbutyl - 5 - ethylnonane

Cycloalkanes1. Start at noon and go clockwise until you get to first carbon with a substituent group this is # 12. Go clockwise or counterclockwise so substituent groups receive the smallest number possible

Cyclical Alkaneshave 2 H less from ring closure

cyclopropane

C3H6 cyclooctaneC8H16

cyclobutane

C4H8

cyclononane

C9H18

Alkanes cyclodecaneC10H20

cycloundecaneC11H22

cyclododecaneC12H24

Practice

1,1-dimethylcyclopentane

methylcyclopentane

Practice

1,3-dimethylcyclopentane

1,2-dimethylcyclopentane

Practice

2-ethyl,1-methylcyclohexane

Practice

2-cyclopropyl-4-ethyl-1-methylcyclohexane