Transcript Chapter 9 Organic chemistry: The Infinite Varietyof Carbon

Chapter 12
Organic Chemistry: The Infinite
Variety of Carbon Compounds
Organic Chemistry
• Chemistry of carbon-containing
compounds
• Most of these come from living things
– Not necessarily the case
• ~30 million chemical compounds known
– 95% are compounds made of carbon
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Carbon
• Able to bond strongly to other carbon
atoms
– Forms long chains
– Very few other atoms can form short
chains, let alone long chains
• Capable of forming ring structures
• Bonds strongly to other elements
– In particular, H, O, and N
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Hydrocarbons
• Made of carbon and hydrogen
• Several classes
• Alkanes
– Contain only single bonds
– Saturated hydrocarbons
– Each C atom bonded to maximum number of H
atoms
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Alkanes
• Chemical formula CnH2n+2
n = 1, 2, 3, …
• CH4, methane, simplest
one
• C2H6, ethane
• All have –ane ending
– Follow a pattern
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• Condensed structural formulas
– Show how many hydrogens are attached
to each carbon
CH3-CH3 for ethane
• Structural formulas show how atoms are
bonded together
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Isomerism
• Isomers: compounds with
same molecular formula but
different structural formulas
• Differences in structure may
give rise to differences in
chemical and physical
properties
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• Number of possible isomers increases
rapidly with the number of carbons
– C30H62 – >4 billion possible isomers
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Properties of Alkanes
• Main property: will burn
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Cyclic Hydrocarbons
• Carbon atom chains in form of rings
• Can be represented by structural
formulas or symbolic representations
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Unsaturated Hydrocarbons
• Can have more hydrogen
atoms added
• Very important in biological
systems
• Alkene: hydrocarbon that
contains one or more carbonto-carbon double bonds
– General formula of CnHn
• Simplest: ethylene, C2H4
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• Alkyne: hydrocarbon that
contains one or more
carbon-to-carbon triple
bonds
• General formula of CnH2n–
2
• Simplest: acetylene, C2H2
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Properties of Alkenes and Alkynes
• Similar physical properties to alkanes
• Undergo more reactions than alkanes
– Addition reaction: add compounds across
double bond
– Importantly, they can form polymers
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Aromatic Hydrocarbons
• Contain double or triple bonds, but do
not show the same reactivity as other
unsaturated hydrocarbons
H
• Benzene: C6H6
• Used mainly as solvents H
H
H
H
H
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Chlorinated Hydrocarbons
• Add Cl to hydrocarbons
– Increase reactivity of alkanes
• Dissolve fats, oils, and greases
– Useful for dry cleaning
• Tend to accumulate in fatty tissues
– If toxic, this will be a problem
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Chlorofluorocarbons and
Fluorocarbons
• Tend to be either liquids or gases
• Completely inert
– Except in upper atmosphere
• O2 soluble in fluorinated compounds
– Temporary substitute for hemoglobin
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Functional Groups
• Group of atoms that gives a family of
organic compounds its characteristic
chemical and physical properties
• Alkyl group: derived from alkane by
removing a H
– R stands for alkyl group in general
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Alcohol Family
•
•
•
•
–OH group
Replace -e with -ol
CH3OH, methanol, simplest
Produced industrially
– Mainly a chemical intermediate
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• C2H5OH, ethanol
• Made industrially and by fermentation
– Industrially produced alcohol has noxious
substances added
• Small, simple alcohols tend to be toxic
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Multifunctional Alcohols
• Several common alcohols have more
than one –OH group
• Ethylene glycol: main ingredient in
antifreeze
• Glycerol: used in lotions
– Ingredent in some explosives
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Phenol
• –OH group on benzene ring
– Different chemical properties than other
alcohols
– Behaves more like an acid
• First antiseptic
– Also causes skin irritation
OH
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Ethers
• Two alkyl groups attached to same O
– Example CH3CH2-O-CH2CH3
• Used mainly as solvent
• Little chemical reactivity
– Insoluble in water
– Highly flammable
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Aldehydes and Ketones
• Both contain carbonyl group (C=O)
• Aldehyde: R-CHO
• Ketone: R-CO-R’
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Common Aldehydes
•
•
•
•
Change -e ending to -al
Produced by oxidation of alcohols
Formaldehyde – used as a preservative
Larger ones used as fragrances
– Benzaldehyde – flavor in maraschino
O
cherries
C
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Common Ketones
• Change -e ending to -one
• Acetone most common ketone
– Used primarily as a solvent
• Produced by oxidation of alcohols
O
C
CH3
H3C
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Carboxylic Acid
• Contains C=O and –OH group on same
carbon
• Change -e to -oic acid
• Acetic acid: acid in vinegar
O
R
C
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Esters
• Derived from carboxylic acids and alcohols
• Tend to be fragrant
– Methyl butyrate
– Ethyl butyrate
– Ethyl formate
– Methyl salicylate
apple
pineapple
rum
wintergreen
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Amines
• Contain N
• May have 1, 2, or 3 alkyl or aromatic
groups
• Most biological amines are amino acids
– Building blocks of proteins
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Amides
• N bonded directly to carbonyl group
• Linkage that holds proteins together
O
R''
R
N
R'
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Heterocyclic Compounds
• Ring compounds that have something
other than C in the ring
• Occur in plants
– Alkaloids: basic in solution
– Examples: caffeine, morphine, cocaine
• Form basic structure of DNA
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