Chapter 20: Organic Chemistry The chemistry of carbon compounds. Mainly carbon and hydrogen atoms....
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Chapter 20: Organic Chemistry The chemistry of carbon compounds. Mainly carbon and hydrogen atoms. Many organic compounds occur naturally. Thousands more can be synthesized by man. 1
Chapter 20: Organic Chemistry The chemistry of carbon compounds. Mainly carbon and hydrogen atoms. Many organic compounds occur naturally. Thousands more
Chapter 20: Organic Chemistry The chemistry of carbon
compounds. Mainly carbon and hydrogen atoms. Many organic compounds
occur naturally. Thousands more can be synthesized by man. 1
Slide 2
NaCl versus Butane NaCl, 58.5 g/mol Bonding is ionic M.P. = 801
o C B.P. = 1413 o C Dissolves in water Will not burn C 4 H 10, 58.1
g/mol Bonding is covalent M.P. = -138 o C B.P. = 0 o C Not soluble
in water Will burn in air 2
Slide 3
Molecular Geometry There are three hybridization states and
geometries found in organic compounds: sp 3 Tetrahedral sp 2
Trigonal planar sp Linear 3
Slide 4
Classes of Organic Compounds 4 AliphaticAromatic
SaturatedUnsaturated AlkanesCycloalkanesAlkenesAlkynes Benzene
Ring
Slide 5
Alkanes Saturated hydrocarbons All C-C single (sigma) bonds
Formula = C n H 2n+2 5
Slide 6
Formulas Structure is very important in organic chemistry.
Propane = C 3 H 8, chemical formula Complete structural drawing
shows every single bond. H H H H C C C H H H H 6
Slide 7
Formulas Condensed structural drawing collapses the H atoms
that are bonded to EACH carbon atom. CH 3 CH 2 CH 3, condensed
formula. This is how a formula is written. 7
Slide 8
Formulas The molecule is really NOT linear, though. The sigma
bonds in the alkanes have free rotation. 8
Slide 9
First Ten Alkanes: Base Names 9
Slide 10
Structural Isomers For four carbons, there are two ways to
arrange. For five carbons, there are three ways to arrange. 10
Slide 11
IUPAC Nomenclature A name of a compound consists of three
parts. Prefix, Base, and Suffix 11 prefixbasesuffix substituents
longest chain (how many Cs) family
Slide 12
IUPAC Nomenclature A substituent is any group that is attached
to the longest chain of carbon atoms. CH 4 = methane, -CH 3 =
methyl CH 3 CH 3 = ethane, -CH 2 CH 3 = ethyl Cl = chloro, Br =
bromo, I = iodo 12
Slide 13
IUPAC Nomenclature 1. Find the longest chain in the molecule.
2. Number the chain from the end nearest the first substituent
encountered. 3. List the substituents as a prefix along with the
number(s) of the carbon(s) to which they are attached. LEP #1
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Slide 14
Cycloalkanes A ring structure can be constructed from alkanes
of three or more carbons by removing two hydrogen atoms. Because
they form a geometric shape, a shorthand method for their structure
is that shape. Rings with 5 and 6 carbons are the most stable.
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Slide 15
IUPAC Nomenclature For ring structures, a mono-substituted ring
does not need a number. Why??? For di-substituted ring structures,
number starting from the location of one the substituents and then
go CW or CCW to give the next one the lowest number. 15
Slide 16
Haloalkanes A haloalkane is placing a halogen (group 7A) atom
in place of a hydrogen atom. Naming uses the fluoro, chloro, bromo,
and iodo names. Haloalkanes are used as refrigerants (CF 3 CH 2 F)
and anesthetic agents (CF 3 CHClBr). 16
Slide 17
Stereoisomerism and Optical Isomerism Stereoisomers = molecules
in which the atoms have the same connectivity, but have a different
spatial arrangement. Geometric = cis / trans (alkenes) Optical
isomers = are two molecules that are non-superimposable. Optical
isomers are much like your hands they are not superimposable!
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Slide 18
Chirality Any carbon with four unique groups bonded to it are
said to be chiral. 18
Slide 19
Chirality 19 If one of the two optical isomers is present, then
it will rotate plane-polarized light to the left or to the right.
An equal amount of both isomers will not rotate the light and is
said to be a racemic mixture.
Slide 20
Chirality Many important biochemical molecules are chiral. Many
important pharmaceuticals have at least one chiral carbon. Ex)
Ibuprofen 20 Chiral Carbon
Slide 21
Properties and Reactions of Alkanes Alkanes are non-polar and,
thus, do NOT dissolve in water. Alkanes typically have a density of
0.65 0.70 g/mL and will float on the surface of water. Alkanes are
relatively unreactive. They burn in air, though, to produce energy.
Halogenation: CH 3 CH 3 + Cl 2 21
Slide 22
Alkenes Called unsaturated Contain at least one C=C double bond
Simplest alkene = C 2 H 4 22
Slide 23
Alkenes The double bond does not allow for free-rotation.
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Slide 24
IUPAC Nomenclature Naming an alkene. 1. Find the longest chain
that includes the double bond. Suffix name uses ene ending. 2.
Number the chain so that the double bond gets the lowest numbers
(has priority over other substituents). Only four carbons or longer
will need a number for the double bond position. Use only the
lowest number for start of double bond. 3. Number substituents
based on this numbering. 4. Cycloalkenes the double bond is ALWAYS
position #1 and #2. 24
Slide 25
Geometric Isomers Some alkenes can have geometric isomers due
to rigid shape around double bond. Requires two different sets of
groups on each side of the double bond one large and one small. AB
C = C BA Opposite = trans, Same side = cis 25
Slide 26
Addition Reactions Alkenes undergo an addition reaction by
adding a small molecule across the double bond. Hydrogenation
Halogenation Hydration 26
Slide 27
Aromatic Hydrocarbons Benzene, C 6 H 6, is a ring structure
like the cycloalkanes. However, it is very different from the
cycloalkanes, whose ring structures are fairly easy to break open.
Benzene is VERY stable and found in many important molecules like
aspirin, vanillin, and acetaminophen. What makes it unique? 27
Slide 28
IUPAC Nomenclature Mono-substituted benzene needs no number.
Some have special (common) names. Toluene, Phenol, and Aniline.
Di-substituted benzene rings are numbered like the cycloalkanes.
Substituted toluenes, phenols, and anilines have those groups as
the first position. 28
Slide 29
Functional Groups Addition of atoms like O, N, and S add
reactivity and polarity to the alkanes. Can occur in many different
ways. Will need to know the nomenclature and reactions of some and
be able to identify all. The letter R is a generic designation for
an alkyl group. 29
Slide 30
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Slide 31
Alcohols Alcohols contain the hydroxyl (OH) group. R-OH
Alcohols are classified as primary, secondary, and tertiary. 31
Primary (1 ) Secondary (2 ) Tertiary (3 ) 1 group 2 groups 3 groups
H CH 3 CH 3 | | | CH 3 C OH CH 3 C OH CH 3 C OH | | | H H CH 3
Slide 32
IUPAC Nomenclature Alcohols get an ol suffix. The OH group MUST
have the lowest number it has priority. On a cycloalkane, it is
carbon #1. On benzene it is called phenol. 32
Slide 33
Properties of Alcohols The OH group can make the molecule
soluble in water due to HB force. C 1 to C 4 are very soluble in
water. More than five carbons, though, is virtually insoluble. CH 3
CH 2 CH 2 CH 2 CH 2 CH 2 - OH 33 long chain is non-polar
(dominates)
Slide 34
Reactions of Alcohols Oxidation = loss of two Hs or gain of O.
Depends on primary, secondary or tertiary. Primary Alcohol Aldehyde
Carboxylic Acid Secondary Alcohol Ketone Tertiary No Reaction
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Slide 35
Ethers An O atom separating two alkyl groups. R O R Oxygen atom
is polar, so smaller ones are soluble in water. CH 3 CH 2 O CH 2 CH
3 MTBE 35
Slide 36
Thiols A sulfur atom usually with an H attached. R SH CH 3 CH 2
SH, Ethanethiol These compounds smell BAD! One amino acid has this
thiol group. 36
Slide 37
Carbonyl Group Many functional groups contain a C = O group.
Aldehyde = the C = O group is terminal. R-CHO CH 3 CH 2 C H O
37
Slide 38
Carbonyl Group Aldehydes use the al suffix. The carbonyl carbon
is automatically the first position. Ketone = the carbonyl group is
in the middle of the chain. Smallest ketone has three carbons
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Slide 39
Carbonyl Group Ketones use an one suffix. Number is needed for
five or more Cs. Carboxylic Acid = carbonyl group with a hydroxyl
group attached. R COOH Are many of the weak acids seen in Ch. 16.
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Slide 40
Carbonyl Group 40 Formulas are written differently! Ex) Acetic
Acid
Slide 41
Carbonyl Group Naming acids use the oic suffix plus the name
acid. Like aldehydes, the COOH group is terminal, so it is C #1.
Esters = has both the carbonyl and the ether type O atom. R COO R
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Slide 42
Carbonyl Group An ester is made by the reaction of an alcohol
and a carboxylic acid. R C OH + HO R R C O R O O The OH and H
produce water. 42
Slide 43
Amine An amine contains the N atom. These can be primary,
secondary, or tertiary. R NH 2, R 2 NH, and R 3 N. The N group has
a lone pair that will accept a proton Therefore, these are the weak
bases from Ch. 16. 43
Slide 44
Amide Contain the carbonyl group AND the amine group. R (C=O)
NH 2 The N group can also have an R group. Made by the reaction of
a carboxylic acid plus an amine. Similar to ester reaction. 44
Slide 45
Polymers A polymer is a long chain of repeating units called
monomers. Monomers are typically small alkenes. Reaction is called
an addition reaction and are referred to as addition polymers
Initiated by organic peroxide, R-O-O-R, which is split into two
fragments, 2 R-O 45 Benzoyl peroxide
Slide 46
Common Monomers CH 2 =CH 2, ethylene makes polyethylene. Two
forms low density and high density Uses: CH 2 =CHCl, vinyl chloride
makes PVC. Uses: CH 2 =CHCH 3, propene makes polypropylene. Uses:
CF 2 =CF 2, tetrafluoroethene makes Teflon. Uses: 46
Slide 47
Common Monomers CH 2 =CCl 2, 1,1-dichloroethene makes Saran.
Uses: CH 2 =CH(C 6 H 5 ), phenylethene makes polystyrene. Uses:
Recycling uses a series of symbols and numbers to identify the
type. 47
Slide 48
Condensation Polymers Polyurethanes, Nylons, Rayons, etc. are
produced using the ester and/or amide reaction. Monomer units have
two functional groups per molecule. PETE = ethylene glycol +
terephthalic acid Nylon 6,6 = adipic acid + hexamethylenediamine
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