Download Chapter 2: Nomenclature and Structure

Chemistry 241
Chapter 2: An Intro to Organic Compounds
Homework: 45 a-j, o, 46, 48, 51 a-d, 54 a-i, 55, 58, 60, 61, 62 a-c, f, 66, 69 a-c, 73
I.
Terms
A. Generic
1.
2.
3.
4.
alkane: all single bonds
hydrocarbon: carbon and hydrogen
substituent: something hanging off of chain; not part of chain
straight chain vs branched chain
5. homologous series: add a carbon to chain to continue series
a. methylene –(CH2)6. isomer
a. constitutional isomers: same formula, different connectivity
i.
butane vs isobutene, 1-chloro vs 2-chloropropane
ii.
isomers of C4H10 (2), C5H12 (3), C6H14 (5)
b. stereo isomers (chapter 3 and later)
7. conformers
a. same molecule drawn from different perspective
B. Nomenclature
1. systematic (IUPAC) vs common
a. every name is unique to one molecule
b. IUPAC gives one name to every molecule, though it may have
several common names
c. IUPAC has prefix-stem (or root)-suffix
i.
prefixes are substituent(s) (may be more than one)
ii.
root/stem is parent molecule
iii.
suffix functional group of parent (alkane, alcohol,
etc)
d. Common names almost always are without numbers
2. alkanes
a. longer table on p 72
# C’s
Parent name
Substituent name
1
methane
methyl
2
ethane
ethyl
3
propane
propyl
4
butane
butyl
5
pentane
pentyl
6
hexane
hexyl
7
heptane
heptyl
1
8
9
10
octane
nonane
decane
octyl
nonyl
decyl
3. drawings (for butane)
a. condensed
CH3CH2CH2CH3
Structure
Functional grp
alcohol
amine
Alkyl halide
ether
b. line diagrams (skeletal structures)
4. branched
Common name
IUPAC name
isobutene
2-methylpropane
isopentane
2-methylbutane
isohexane
2-methylpentane
5. functional groups (IUPAC)
Structure
Prefix
-OH
hydroxy-NH2
amino-F
fluoro-Cl
chloro-Br
bromo-I
iodoC-O-C
methoxyethoxyetc
Suffix
-ol
-amine
C. miscellaneous
1. Types of carbons, hydrogens, amines
a. primary (1º)
i.
C, N connected to one other C
ii.
H attached to C which is connected to one other C
b. secondary (2º)
i.
C, N connected to two other C’s
ii.
H attached to C which is connected to two other C’s
c. tertiary (3º)
i.
C, N connected to three other C’s
ii.
H attached to C which is connected to three other C
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d. quaternary (4º)
i.
C, N connected to four other C
ii.
H not possible
2. more alkyl substituents
R
a. butyl-, n-butylb. isobutyl-, (IUPAC = (2-methylpropyl))
R
R
c. sec-butyl
R
II.
d. tert-butyl
Alkane Nomenclature
A. IUPAC system
1. prefix – stem (or root) - suffix
B. Straight and branched chains
p78
1. find longest carbon chain
a. longest carbon chain with parent (chain includes alcohol, for ex)
2. if a tie, parent chain (two or more possible), parent is one that
has more substituents (more substituents = easier to name)
3. name and number substituents
a. substituent is prefix
b. number from side that gives smaller number
c. common names almost never have number
4. if more than one substituent
a. if more than one of same substituent, use di-, tri-, tetra-, penta-,
hexa-, heptai. 1,1 dichloroethane
b. for every substituent, there is a number
c. substituents are put into alphabetical order
i.
di, tri, tetra, (etc), sec, and tert ignored for
alphabetizing
ii.
iso and cyclo count for alphabetizing
iii.
cyclopentyl before isobutyl, dibromo before chloro
5. numbering more than one substituent
a. number from side that gives lowest first substituent number
b. if tie, keep going until tie-breaker reached (1st point of
difference)
3
C.
D.
E.
F.
G.
6. can use “iso-,” “sec-,” or “tert-,” but IUPAC substituent on a
substituent method preferred
7. moosh entire thing into one word
a. dashes separate words and numbers
b. commas separate numbers
Cyclics
p82
1. count the carbons and add “cyclo” in front
2. if one substituent, no need for numbers
3. if alkyl substituents, either can be parent
4. if more than one substituent, give both numbers, 1st in alphabet
is number 1
Alkyl halides
p85
1. common names
a. no numbers
b. sec, iso indicate location of halogen
2. IUPAC already covered
Ethers
p86
1. common
a. carbon chains on either side are substiuents
b. two words
c. parent and suffix is ether
d. sec, iso indicate location of oxygen
e. ethyl isobutyl ether, dimethyl ether
2. IUPAC
a. smaller, less complicated carbon chain and oxygen are
substituent
b. name change of substituent: drop “yl” and “oxy”
i. CH3- methyl becomes CH3O- methoxy
Alcohols
p87
1. common
a. carbon chain is substituent, parent and suffix = alcohol
b. two words
c. sec, iso indicate location of halogen
d. methyl alcohol, isopropyl alcohol
2. IUPAC
a. longest carbon chain containing the –OH functional grp
b. suffix is “ol” instead of “ane”
c. straight chains: number from side that gives lowest number to
-OH
d. where to put number
i.
can put it immediately before “ol”
ii.
or immediately before root
iii.
2-butanol or butan-2-ol
e. cyclics: alcohol is number 1, no need to give number if more
than one substituent
Amines
p89
4
1.
a.
2.
a.
b.
III.
IV.
common
name all alkyl substituents in front, parent and suffix = amine
IUPAC
if primary, can name amine as “amino” substituents
or, if primary, can name amine as parent
i. drop “e” from “ane,” and add amine
c. if 2º, 3º, additional chains, alkyl substituents on nitrogen given
“N” designation
d. alphabetize substituents (N treated as number, not for alphabet)
e. if 4º, = quaternary ammonium salt
i.
name as salt (cation, then anion)
ii.
list four alkyl groups, then ammonium
H. Summary
p91
Physical Properties
A. Boiling
1. What is it/ what happens
2. Intermolecular forces
a. H-bonding
b. dipole-dipole attractions
c. induced dipole- induced dipole, London dispersion, Van der
Waals forces
3. Tables of physical properties of different functional grps in
Appendix I
B. Melting/Freezing
1. crystal packing
C. Solubility
1. like dissolves like
2. polar solvents like polar molecules
3. non-polar solvents like non-polar solutes
4. if immiscible, less dense floats
sp3 carbon bonds
A. Properties
1. 109.5º
2. free rotation, unlike sp2 or sp
B. Newman projections
1. sawhorse projections
2. ethane
a. eclipsed
b. staggered (conformers)
c. 60º clicks
3. butane
a. looking down C2-C3 bond
b. anti
c. gauche
d. steric strain
4. energy diagrams p102, and p104
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C. Cyclohexane
1. chair
a. my drawing
b. book
c. Newman
2. axial and equatorial
a. axial
b. equitorial
3. ring flip
a. what was axial is now equatorial and verse-visa
4. boat
5. strains (p109 table of energies)
a. chair lower in energy than boat
b. cyclic strain of propane, butane
6. energy diagrams p110
7. axial groups interact
a. larger groups prefer equatorial so no interference
b. ring flip to get there
8. disubstituted cyclohexanes
a. 1,2 or 1,3 or 1,4
b. cis
c. trans
d. energy of cis, trans, ringflips
Objectives
Knowledge
Memorize the terms for the first ten alkanes (methane  decane) (p72)
Recall how to name alcohols (drop “-e” on alkane, add “-ol”) and amines
Remember the common names isopropyl, isobutyl, tertiary (tert-, or t-) butyl, n- (normal)
Recall the rules for IUPAC naming of alcohols, amines, alkyl halides, ethers, and alkanes
(including cyclic compounds)
Define the terms anti and gauche, eclipsed and staggered, boat and chair, axial and
equatorial, cis and trans, Newman and sawhorse projections
Comprehension
Explain how inter- and intramolecular forces affect physical properties (mp, solubility..)
Understand the classification system for carbons, hydrogens, and amines (1°, 2°, 3°, 4° )
Recognize the contributions to the stability of ring size, anti and gauche, eclipsed and
staggered, boat and chair, axial and equatorial, cis and trans,
Application
Use IUPAC rules to name Lewis structures and line diagrams
From the IUPAC name, be able to draw the structure
Employ energy diagrams to show relative energy of conformers (eclipsed/staggered, etc.)
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