Introductory Organic Chemistry Chem 212 & Chem 211
Dr. Laura PavelkaDepartment of Chemistry
Pulp & Paper [email protected]
ORGANIC BITES 2A: BASIC ALKANES
CHEM 212/211 Organic Bites 2A ‐ Chapter 4 2
LET’S REVIEW ALKANE NOMENCLATURE...
Section 2 – Alkanes and CycloalkanesChapter 4 – Nomenclature and Conformations
Simple Alkanes and CycloalkanesNaming Branched AlkanesNaming Branched Cycloalkanes
Overview of Alkanes and Cycloalkanes
CHEM 212/211 Organic Bites 2A ‐ Chapter 4 3
CYCLOALKANES: rings, all σ‐bonds, tetrahedral, sp3
H
H
H
H
H
H
H
H
H H
H
H
H
HH H
ALKANES: “saturated”, all σ bonds, tetrahedral, sp3
H
CH H
H
CHEM 212/211 Organic Bites 2A ‐ Chapter 4 4
Alkanes: “saturated”, only σ‐bonds (CnH2n+2)
CH4 METHANE bp = ‐164 °CCH3CH3 ETHANE C2H6 bp = ‐ 89 °CCH3CH2CH3 PROPANE C3H8 bp = ‐ 42 °C
CC
CH H
HHHH
HH
≡
CHEM 212/211 Organic Bites 2A ‐ Chapter 4 5
Alkanes: “saturated”, only σ‐bonds (CnH2n+2)
CH4 METHANE bp = ‐164 °CCH3CH3 ETHANE C2H6 bp = ‐ 89 °CCH3CH2CH3 PROPANE C3H8 bp = ‐ 42 °CCH3CH2CH2CH3 BUTANE C4H10 bp = 0 °C
≡
CHEM 212/211 Organic Bites 2A ‐ Chapter 4 6
Alkanes: “saturated”, only σ‐bonds (CnH2n+2)
CH4 METHANE bp = ‐164 °CCH3CH3 ETHANE C2H6 bp = ‐ 89 °CCH3CH2CH3 PROPANE C3H8 bp = ‐ 42 °CCH3CH2CH2CH3 BUTANE C4H10 bp = 0 °CCH3CH(CH3)2 ISOBUTANE bp = ‐11 °C
≡
≡STRUCTURAL ISOMERS(same formula, different connectivity)
CHEM 212/211 Organic Bites 2A ‐ Chapter 4 7
Alkanes: “saturated”, only σ‐bonds (CnH2n+2)
CH4 METHANE bp = ‐164 °CCH3CH3 ETHANE C2H6 bp = ‐ 89 °CCH3CH2CH3 PROPANE C3H8 bp = ‐ 42 °CCH3CH2CH2CH3 BUTANE C4H10 bp = 0 °CCH3(CH2)3CH3 PENTANE C5H12 bp = 36 °CCH3CH2CH(CH3)2 ISOPENTANE bp = 28 °CCH3C(CH3)3 NEOPENTANE bp = 10 °C
CC
CH C
HHHH
HH
C
HH
H
HH
≡STRUCTURAL ISOMERS
CHEM 212/211 Organic Bites 2A ‐ Chapter 4 8
Alkanes: “saturated”, only σ‐bonds (CnH2n+2)
CH4 METHANE bp = ‐164 °CCH3CH3 ETHANE C2H6 bp = ‐ 89 °CCH3CH2CH3 PROPANE C3H8 bp = ‐ 42 °CCH3CH2CH2CH3 BUTANE C4H10 bp = 0 °CCH3(CH2)3CH3 PENTANE C5H12 bp = 36 °CCH3(CH2)4CH3 HEXANE C6H14 bp = 69 °CCH3(CH2)2CH(CH3)2 ISOHEXANE bp = 60 °CCH3CH2C(CH3)3 NEOHEXANE bp = 50 °CCH3CH2CH(CH3)CH2CH3 bp = 63 °C(CH3)2CHCH(CH3)2 bp = 58 °C
STRUCTURAL ISOMERS
CHEM 212/211 Organic Bites 2A ‐ Chapter 4 9
Alkanes: “saturated”, only σ‐bonds (CnH2n+2)
CH4 METHANE bp = ‐164 °CCH3CH3 ETHANE C2H6 bp = ‐ 89 °CCH3CH2CH3 PROPANE C3H8 bp = ‐ 42 °CCH3CH2CH2CH3 BUTANE C4H10 bp = 0 °CCH3(CH2)3CH3 PENTANE C5H12 bp = 36 °CCH3(CH2)4CH3 HEXANE C6H14 bp = 69 °CCH3(CH2)5CH3 HEPTANE C7H16 bp = 98 °CCH3(CH2)6CH3 OCTANE C8H18 bp = 125 °CCH3(CH2)7CH3 NONANE C9H20 bp = 151 °CCH3(CH2)18CH3 EICOSANE C20H42 bp = 343 °C
366 319 structural isomers!
CHEM 212/211 Organic Bites 2A ‐ Chapter 4 10
Alkanes: “saturated”, only σ‐bonds (CnH2n+2)
GASES
LIQUIDS
CH4 METHANE bp = ‐164 °CCH3CH3 ETHANE C2H6 bp = ‐ 89 °CCH3CH2CH3 PROPANE C3H8 bp = ‐ 42 °CCH3CH2CH2CH3 BUTANE C4H10 bp = 0 °CCH3(CH2)3CH3 PENTANE C5H12 bp = 36 °CCH3(CH2)4CH3 HEXANE C6H14 bp = 69 °CCH3(CH2)5CH3 HEPTANE C7H16 bp = 98 °CCH3(CH2)6CH3 OCTANE C8H18 bp = 125 °CCH3(CH2)7CH3 NONANE C9H20 bp = 151 °CCH3(CH2)18CH3 EICOSANE C20H42 bp = 343 °C
Cycloalkanes: rings, only σ‐bonds (CnH2n)
CHEM 212/211 Organic Bites 2A ‐ Chapter 4 11
ALKANES = CnH2n+2 CYCLOALKANES = CnH2n
DIFFERENCE IN # HYDROGENS = (2n+2) ‐ 2n = 2UNITS OF UNSATURATION = 1 (1 per 2 Hs)
Cycloalkanes: rings, only σ‐bonds (CnH2n)
CHEM 212/211 Organic Bites 2A ‐ Chapter 4 12
cyclopropaneC3H6
cyclobutaneC4H8
cyclopentaneC5H10
cyclohexaneC6H12
ALKANES = CnH2n+2 CYCLOALKANES = CnH2n
DIFFERENCE IN # HYDROGENS = (2n+2) ‐ 2n = 2UNITS OF UNSATURATION = 1 (1 per 2 Hs)
cycloheptaneC7H14
cyclooctaneC8H16
cyclononaneC9H18
cyclodecaneC10H20
Alkanes: Boiling/Melting Point Trends
CHEM 212/211 Organic Bites 2A ‐ Chapter 4 13
ALKANE BOILING/MELTING POINT INCREASES WITH # CARBONS
Alkanes: Solubility
CHEM 212/211 Organic Bites 2A ‐ Chapter 4 14
ALKANES ARE HYDROPHOBIC AND DO NOT dissolve in water (uncharged/non‐polar)
Alkanes: Density
CHEM 212/211 Organic Bites 2A ‐ Chapter 4 15
ALKANES ARE THE LEAST DENSE OF ALL ORGANIC COMPOUNDS (weak intermolecular forces)
LIQUID ALKANES ~ 0.6‐0.8 g/mL
CHEM 212/211 Organic Bites 2A ‐ Chapter 4 16
5‐10
carbons
“gasoline”
C5H12 to C10H22
Alkanes: Gasoline
CHEM 212/211 Organic Bites 2A ‐ Chapter 4 17
C12H26 to C18H38
“kerosene”
12‐18
carbons
Alkanes: Kerosene
CHEM 212/211 Organic Bites 2A ‐ Chapter 4 18
ROOFING
20‐50
carbons
“tar” or “wax”
C20H42 to C50H102
Alkanes: Tar and Wax
CHEM 212/211 Organic Bites 2A ‐ Chapter 4 19
VASELINE
20‐50
carbons
“tar” or “wax”
C20H42 to C50H102
Alkanes: Petroleum Jelly
CHEM 212/211 Organic Bites 2A ‐ Chapter 4 20
10,000
carbons
“polyethylene”PLASTIC BOTTLES
Alkanes: Hydrocarbon Polymers
THOSE ARE THE NAMES AND ISOMERS OF THE SIMPLE ALKANES...
BUT, HOW DO YOU NAME MORE COMPLEX
OR SUBSTITUTED ALKANES?
CHEM 212/211 Organic Bites 2A ‐ Chapter 4 21
CHEM 212/211 Organic Bites 2A ‐ Chapter 4 22
LET’S REVIEW ALKANE NOMENCLATURE...
Section 2 – Alkanes and CycloalkanesChapter 4 – Nomenclature and Conformations
Simple Alkanes and CycloalkanesNaming Branched AlkanesNaming Branched Cycloalkanes
1. Select the longest continuous chain of carbon atoms for the basic name. (not necessarily “linear”)
2. Number the carbons in the chain from the end nearest the first branch/substituent.
3. Identify substituents (e.g. methyl, ethyl, bromo, chloro). If more than one substituent of the same kind is present, use the prefixes “di,” “tri”or “tetra.”
4. Locate the numbered carbon to which the substituents are attached.
5. Put substituents in alphabetical order (multiplier prefixes do not count).
6. Separate numbers from letters by a dash and write the whole name as one word with the basic name at the end.
CHEM 212/211 Organic Bites 2A ‐ Chapter 4 23
IUPAC System of Naming Alkane Derivatives
Methyl & Primary Alkyl Substituents
CHEM 212/211 Organic Bites 2A ‐ Chapter 4 24
CH3 H
CH3CH2CH2 H
CH3
CH3CH2CH2
Methyl
Ethyl
Propyl
Butyl
Methane
Ethane
Propane
Butane
1° carbon
1° carbon
1° carbon
Naming Practice – Alkanes
CHEM 212/211 Organic Bites 2A ‐ Chapter 4 25
1. Longest continuous chain – basic name2. Number carbons 3. Identify substituents4. Number substituents5. Alphabetize substituents6. Whole name as one word (numbers/letters divided by dashes)
3 2
3
2 2 3
2 2 3
2 3
Naming Practice – Alkanes
CHEM 212/211 Organic Bites 2A ‐ Chapter 4 26
1. Longest continuous chain – basic name2. Number carbons 3. Identify substituents4. Number substituents5. Alphabetize substituents6. Whole name as one word (numbers/letters divided by dashes)
2,2,4,4‐tetramethylpentane
Naming Practice – Alkanes
CHEM 212/211 Organic Bites 2A ‐ Chapter 4 27
1. Longest continuous chain – basic name2. Number carbons – if a tie (two # options), alphabet wins3. Identify substituents4. Number substituents5. Alphabetize substituents6. Whole name as one word (numbers/letters divided by dashes)
CHEM 212/211 Organic Bites 2A ‐ Chapter 4 28
Naming Practice – Alkanes1. Longest continuous chain – basic name2. Number carbons – if a tie, most substituted chain wins3. Identify substituents4. Number substituents5. Alphabetize substituents6. Whole name as one word (numbers/letters divided by dashes)
Naming Practice – Alkanes
CHEM 212/211 Organic Bites 2A ‐ Chapter 4 29
1. Longest continuous chain – basic name2. Number carbons – if a tie, lowest total numbering wins3. Identify substituents4. Number substituents5. Alphabetize substituents6. Whole name as one word (numbers/letters divided by dashes)
2,3,5‐trimethylhexane
OK... THAT’S NAMING BRANCHED ALKANES...
... WHAT ABOUT RING SYSTEMS?
CHEM 212/211 Organic Bites 2A ‐ Chapter 4 30
CHEM 212/211 Organic Bites 2A ‐ Chapter 4 31
LET’S REVIEW ALKANE NOMENCLATURE...
Section 2 – Alkanes and CycloalkanesChapter 4 – Nomenclature and Conformations
Simple Alkanes and CycloalkanesNaming Branched AlkanesNaming Branched Cycloalkanes
1. Determine the number of carbon atoms in the ring.
2. Add the prefix cyclo‐ to the name of the corresponding alkane.
3. If only one substituent: not necessary to designate number.
4. If two substituents: assign C1 to substituent first in the alphabet and number in the direction that gives next substituent the lowest number.
5. If three substituents or more: begin at the substituent that leads to the lowest overall (total) numbering of the other substituents.
6. If ring is attached to a linear chain with more carbons than the ring system or if more than one ring system is attached to a single chain, name ring(s) as the substituent (cycloalkyl group).
IUPAC System of Naming Cycloalkanes
CHEM 212/211 Organic Bites 2A ‐ Chapter 4 32
CHEM 212/211 Organic Bites 2A ‐ Chapter 4 33
Naming Practice – Cycloalkanes1. Determine ring size – basic name with prefix “cyclo”2. 1 sub: no numbers3. 2 sub: alphabet winner/alcohol assigned C14. 3 sub: lowest overall numbering5. Name as cycloalkyl group if longer linear chain present
CHEM 212/211 Organic Bites 2A ‐ Chapter 4 34
Naming Practice – Cycloalkanes1. Determine ring size – basic name with prefix “cyclo”2. 1 sub: no numbers3. 2 sub: alphabet winner/alcohol assigned C14. 3 sub: lowest overall numbering5. Name as cycloalkyl group if longer linear chain present
1‐ethyl‐3‐propylcycloheptane
CHEM 212/211 Organic Bites 2A ‐ Chapter 4 35
Naming Practice – Cycloalkanes1. Determine ring size – basic name with prefix “cyclo”2. 1 sub: no numbers3. 2 sub: alphabet winner/alcohol assigned C14. 3 sub: lowest overall numbering5. Name as cycloalkyl group if longer linear chain present
2‐ethyl‐1,4‐dipropylcyclohexane
CHEM 212/211 Organic Bites 2A ‐ Chapter 4 36
Naming Practice – Cycloalkanes1. Determine ring size – basic name with prefix “cyclo”2. 1 sub: no numbers3. 2 sub: alphabet winner/alcohol assigned C14. 3 sub: lowest overall numbering5. Name as cycloalkyl group if longer linear chain present
Organic Bites 2A: Main Objectives
CHEM 212/211 Organic Bites 2A ‐ Chapter 4 37
1. Identify/name simple alkanes and cycloalkanes based on structure or condensed formula.
2. Understand the trends in boiling/melting points.3. Rationalize alkane solubility and density.4. Name alkanes/cycloalkanes with simple hydrocarbon
substituents, given a structure.5. Draw structures for alkanes/cycloalkanes with simple
hydrocarbon substituents, given a name.