chapter 9 organic chemistry: the infinite variety of carbon compounds daniel fraser university of...
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Chapter 9 Organic Chemistry: The Infinite Variety of Carbon Compounds
Daniel Fraser
University of Toledo, Toledo OH
©2004 Prentice Hall
Chemistry for Changing Times 10th editionHill/Kolb
Chapter 9 2
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
Chapter 9 3
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
Chapter 9 4
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
Chapter 9 5
Alkanes
• Chemical formula CnH2n+2 n = 1, 2, 3, …
• CH4, methane, simplest one
• C2H6, ethane
• All have –ane ending– Follow a pattern
Chapter 9 6
• Condensed structural formulas– Show how many hydrogens are attached to
each carbon
CH3-CH3 for ethane
• Structural formulas show how atoms are bonded together
Chapter 9 7
Isomerism• Isomers: compounds with
same molecular formula but different structural formulas
• Differences in structure may give rise to differences in chemical and physical properties
Chapter 9 8
• Number of possible isomers increases rapidly with the number of carbons– C30H62 – >4 billion possible isomers
Chapter 9 9
Chapter 9 10
Properties of Alkanes• Main property: will burn
Chapter 9 11
Cyclic Hydrocarbons• Carbon atom chains in form of rings
• Can be represented by structural formulas or symbolic representations
Chapter 9 12
Unsaturated Hydrocarbons
• Can have more hydrogen atoms added
• Very important in biological systems
• Alkene: hydrocarbon that contains one or more carbon-to-carbon double bonds– General formula of CnHn
• Simplest: ethylene, C2H4
Chapter 9 13
• Alkyne: hydrocarbon that contains one or more carbon-to-carbon triple bonds
• General formula of CnH2n–2
• Simplest: acetylene, C2H2
Chapter 9 14
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
Chapter 9 15
Aromatic Hydrocarbons• Contain double or triple bonds, but do
not show the same reactivity as other unsaturated hydrocarbons
• Benzene: C6H6
• Used mainly as solvents
H
H
H
H
H
H
Chapter 9 16
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
Chapter 9 17
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
Chapter 9 18
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
Chapter 9 19
Chapter 9 20
Alcohol Family• –OH group
• Replace -e with -ol
• CH3OH, methanol, simplest
• Produced industrially– Mainly a chemical intermediate
Chapter 9 21
• C2H5OH, ethanol
• Made industrially and by fermentation– Industrially produced alcohol has noxious
substances added
• Small, simple alcohols tend to be toxic
Chapter 9 22
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
Chapter 9 23
Phenol
• –OH group on benzene ring – Different chemical properties than other
alcohols– Behaves more like an acid
• First antiseptic– Also causes skin irritation
OH
Chapter 9 24
Ethers
• Two alkyl groups attached to same O– Example CH3CH2-O-CH2CH3
• Used mainly as solvent
• Little chemical reactivity– Insoluble in water– Highly flammable
Chapter 9 25
Chapter 9 26
Aldehydes and Ketones• Both contain carbonyl group (C=O)
• Aldehyde: R-CHO
• Ketone: R-CO-R’
Chapter 9 27
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
cherries
C
O
H
Chapter 9 28
Common Ketones• Change -e ending to -one
• Acetone most common ketone– Used primarily as a solvent
• Produced by oxidation of alcohols
CH3
C
H3C
O
Chapter 9 29
Chapter 9 30
Carboxylic Acid• Contains C=O and –OH group on same
carbon
• Change -e to -oic acid
• Acetic acid: acid in vinegar
R C
OH
O
Chapter 9 31
Chapter 9 32
Esters• Derived from carboxylic acids and alcohols
• Tend to be fragrant– Methyl butyrate apple– Ethyl butyrate pineapple– Ethyl formate rum– Methyl salicylate wintergreen
Chapter 9 33
Amines• Contain N
• May have 1, 2, or 3 alkyl or aromatic groups
• Most biological amines are amino acids– Building blocks of proteins
Chapter 9 34
Amides• N bonded directly to carbonyl group
• Linkage that holds proteins together
R N
R''
O
R'
Chapter 9 35
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
Chapter 9 36
End of Chapter 9