1.2 Hydrocarbons Naming Alkanes

Organic Chemistry Hydrocarbons Aliphatic Aromatic (Arenes) benzene Alkanes (single bonds) Alkenes (double bonds) Alkynes (triple bonds) benzene propane propene propyne Saturated Unsaturated

Hydrocarbons Are made of only C & H Saturated hydrocarbons (alkanes) are the simplest of the  hydrocarbons and are composed entirely of single bonds and are “saturated” with hydrogen.  Unsaturated hydrocarbons have one or more double or triple  bonds between carbon atoms. Those with double bond are  called alkenes.Those containing triple bonds are called alkynes. Cycloalkanes/Cycloalkenes are hydrocarbons containing one or  more carbon rings. Aromatic hydrocarbons, also known as arenes, are  hydrocarbons that have at least one benzene ring.

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

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

Types of Hydrocarbons

THE SUFFIX: Type of Bonds Family Suffix Single Alkane -ane Double Indicates the family Type of Bonds Family Suffix Single Alkane -ane Double Alkene -ene Triple Alkyne -yne

THE ROOT: How long is the Main Chain? Number of C Atoms Root 1 Methane 2 Ethane 3 Propane 4 Butane 5 Pentane 6 Hexane 7 Heptane 8 Octane 9 Nonane 10 Decane

ALKANES ALKENES ALCOHOLS CH4 CH2 =CH2 CH3OH Homologous series This is a series of compounds which all contain the same functional group, and have similar chemical properties.  ALKANES ALKENES ALCOHOLS CH4 CH2 =CH2 CH3OH CH3-CH3 CH2 =CH –CH3 CH3CH2OH Each has a general formula: ALKANES: CnH2n+2 ALKENES: CnH2n ALKYNES: CnH2n-2 The members of the series differ by the number of CH2 units. CH3-CH3, CH3-CH2-CH3, CH3-CH2-CH2-CH3 Graduation in physical properties:  eg: boiling points. CH4 (GAS), C8H18 (LIQUID), C30H62 (SOLID)

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

NOMENCLATURE OF ORGANIC COMPOUNDS Prefix + Root + Suffix Indicates the name and location of each branch of functional group Tells you how many carbons are in the main chain Indicates the family

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

Naming Branched Alkanes Based off the number of C atoms in the longest chain Count the number of C’s in the longest chain Determine the appropriate root Use the numbered C’s to give the branches a position number add “yl” suffix Add the suffix “ane”

Hydrocarbon Root Names # of Carbons Root Name 1 Methyl 2 ethyl 3 propyl 4 butyl 5 pentyl 6 hexyl 7 heptyl 8 octyl 9 nonyl 10 decyl

Naming Branched Alkanes Important Rules: Start numbering from the end that will give you the lowest number of branches If there is more than one type of branch, name the branches in alphabetical order If there is more than two of the same type of branch, give the branch a position number and prefixes “di”, “tri” “tetra” etc. Put commas between numbers and hyphens between numbers and letters

Rules for Naming Alkanes (Nomenclature) When alkane groups appear as substituents, they are named by dropping the -ane and adding -yl. —CH3 Methyl —CH2CH3 Ethyl —CH2CH2CH3 Propyl —CH2CH2CH2CH3 Butyl Methyl

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. 1 2 3 4 Methyl

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. 1 2 3 4 Name: 2-methylbutane Methyl

Nomenclature Practice Name this compound 1 9 carbons = nonane 2 4 3 5 6 7 8 9 Step #1: For a branched hydrocarbon, the longest continuous chain of carbon atoms gives the root name for the hydrocarbon

Nomenclature Practice Name this compound 9 carbons = nonane 1 2 4 3 5 6 CH3 = methyl 7 chlorine = chloro 8 9 Step #2: When alkane groups appear as substituents, they are named by dropping the -ane and adding -yl.

Nomenclature Practice Name this compound 9 carbons = nonane 1 2 4 3 5 6 CH3 = methyl 7 chlorine = chloro 8 9 1 9 NOT 9 1 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.

Nomenclature Practice Name this compound 9 carbons = nonane 1 2 4 3 5 6 CH3 = methyl 7 chlorine = chloro 8 9 2-chloro-3,6-dimethylnonane 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.

Cyclic Alkanes Cyclopropane, C3H6 Cyclobutane, C4H8 Cyclopentane, C5H10 Cyclohexane, C6H12 Cycloheptane, C7H14 Remember, explicit hydrogens are left out

Practice Makes Perfect

THE SUFFIX: Type of Bonds Family Suffix Single Alkane -ane Double Indicates the family Type of Bonds Family Suffix Single Alkane -ane Double Alkene -ene Triple Alkyne -yne

THE ROOT: How long is the Main Chain? Number of C Atoms Root 1 Meth- 2 Eth- 3 Prop- 4 But- 5 Pent- 6 Hex- 7 Hept- 8 Oct- 9 Non- 10 Dec-

butane Example 1 Longest chain has 4 carbons: Root is But Single bonds main chain (Alkane family) : Suffix is ane Name: but + ane butane 1 2 3 4

2-methylpropane Example 2 Longest Chain has 3 carbons: Root = Prop Branching chain on carbon # 2 Prefix: 2-methyl Single Bonds main chain (Alkane): Suffix- ane 2-methylpropane

Example 3 Longest chain has 7 carbons: Root is Hept Branching chain on Carbon 3 Prefix: 3-methyl Single bonds main chain (Alkane) : Suffix is ane 3-methylheptane

4-ethyl-2-methylhexane Example 4 Longest chain has 6 Carbons: Root is Hex Two branching chains: 2 carbons (ethyl) & 1 carbon (methyl) Single bonds main chain (Alkane) Suffix: ane Use lowest numbering for the branching chain and place in alphabetic order 4-ethyl-2-methylhexane Prefixes

Naming Alkenes & Alkynes 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 Identify the position numbers of branches Same rules as before Write the branches in alphabetical order Write the root, including a prefix that identifies the position of the double/triple bond Add the prefix “cyclo” if its cyclic Add the suffix “ene” or “yne”

Naming Alkenes & Alkynes

THE SUFFIX: Type of Bonds Family Suffix Single Alkane -ane Double Indicates the family Type of Bonds Family Suffix Single Alkane -ane Double Alkene -ene Triple Alkyne -yne

THE ROOT: How long is the Main Chain? Number of C Atoms Root 1 Meth- 2 Eth- 3 Prop- 4 But- 5 Pent- 6 Hex- 7 Hept- 8 Oct- 9 Non- 10 Dec-

butane Example 1 Longest chain has 4 carbons: Root is But Single bonds main chain (Alkane family) : Suffix is ane Name: but + ane butane 1 2 3 4

2-methylpropane Example 2 Longest Chain has 3 carbons: Root = Prop Branching chain on carbon # 2 Prefix: 2-methyl Single Bonds main chain (Alkane): Suffix- ane 2-methylpropane

Example 3 Longest chain has 7 carbons: Root is Hept Branching chain on Carbon 3 Prefix: 3-methyl Single bonds main chain (Alkane) : Suffix is ane 3-methylheptane

4-ethyl-2-methylhexane Example 4 Longest chain has 6 Carbons: Root is Hex Two branching chains: 2 carbons (ethyl) & 1 carbon (methyl) Single bonds main chain (Alkane) Suffix: ane Use lowest numbering for the branching chain and place in alphabetic order 4-ethyl-2-methylhexane Prefixes

Example 5 Longest chain has 4 carbons: Root name: But One double bond in main chain (ALKENE) Suffix: ene Give the lowest number to the double bond 2- butene

Example 6 2-methyl-3-pentene Longest chain has 5 carbons: Root is pent One double bond in main chain (Alkene) suffix: -ene Branching chain (1 carbon) at carbon 2 Prefix is methyl 2-methyl-3-pentene

Example 7 2,5-heptadiene Longest chain has 7 carbons: Root is Hept 1 3 4 7 6 5 Longest chain has 7 carbons: Root is Hept Two double bonds in main chain (Alkene) Suffix: diene (because there are 2 double bonds) 2,5-heptadiene

Example 8 2,5-dimethyl-3-heptene Longest chain has 7 carbons: Root is Hept One double bond in main chain (Alkene) suffix: -ene Two branching chain with one carbon each (at C2 and C5): Prefix is dimethyl 2,5-dimethyl-3-heptene

Example 9 cyclopentane Number of carbons in ring is 5: Root name: pent 4 3 2 5 1 Number of carbons in ring is 5: Root name: pent Single bonds in ring (alkane) suffix: ane Ring: cyclo cyclopentane

Priority List -OH -NH2 -F, -Cl, -Br, -I -CH2CH2CH3 -CH2CH3 -CH3 

Naming Aromatics Same rules If benzene is the parent chain “benzene” suffix If benzene is a branch group “phenyl”

Example 10 Number the carbons in the benzene ring. If more than 1 type of branch is attached to the ring, start C1 where there is the most complex substituent. If only 1 branch is found you do not need to use the suffix -1.