Chemistry 121(01) Winter 2009 Introduction to Organic Chemistry and Biochemistry Introduction to Organic Chemistry and Biochemistry Chapter 12. Saturated Hydrocarbons Chapter 12. Saturated Hydrocarbons Instructor Dr. Upali Siriwardane (Ph.D. Ohio State) E-mail: upali@chem.latech.edu Office: 311 Carson Taylor Hall ; Phone: 318-257-4941; Office Hours: MTW 9:00 am - 11:00 am; TR 9::00 - !0:00 am & 1:00-2:00 pm. December 19, Test 1 (Chapters 12-14) Sections Sections 12.4 12.4- -12.14 & 12.6 12.14 & 12.6 January 2 Test 1 (Chapters 15-16) February 6 (Chapters 17-19) February 27, (Chapters 20-22) March 2, 2009, Make Up Exam: Bring Scantron Sheet 882-E Chemistry 121, Winter 2008, LA Tech Chemistry 121, Winter 2008, LA Tech 1-1 Chemistry 121, Winter 2008, LA Tech Chemistry 121, Winter 2008, LA Tech 1-2 Chapter 12. Saturated Hydrocarbons Chapter 12. Saturated Hydrocarbons Types of formula for organic compounds Types of formula for organic compounds 12.4 12.4 Alkanes: Acyclic Saturated Hydrocarbons Alkanes : Acyclic Saturated Hydrocarbons 12.6 12.6 Alkane Isomerism Alkane Isomerism Chemical formula: Indicate the kind and number of each : Indicate the kind and number of each Chemical formula 12.7 12.7 Conformations of Alkanes Conformations of Alkanes type of atom in the molecule. type of atom in the molecule. 12.8 IUPAC Nomenclature for Alkanes Alkanes 12.8 IUPAC Nomenclature for 12.10 12.10 Classification of Carbon Atoms Classification of Carbon Atoms Condensed formula: Shows skeletal atoms in a molecule Condensed formula : Shows skeletal atoms in a molecule 12.11 12.11 Branched- Branched -Chain Alkyl Groups Chain Alkyl Groups and places them in a sequential order that indicates and places them in a sequential order that indicates 12.12 12.12 Cycloalkanes Cycloalkanes 12.13 12.13 IUPAC Nomenclature for Cycloalkanes IUPAC Nomenclature for Cycloalkanes bonding. bonding. 12.14 12.14 Isomerism in Cycloalkanes Isomerism in Cycloalkanes Structural formula: Shows each atom and bonds in a Structural formula : Shows each atom and bonds in a 12.15 12.15 Sources of Alkanes Sources of Alkanes and and Cycloalkanes Cycloalkanes 12.16 Physical Properties of Alkanes Alkanes and and Cycloalkanes Cycloalkanes molecule. 12.16 Physical Properties of molecule. 12.17 Chemical Properties of Alkanes Alkanes and and Cycloalkanes Cycloalkanes 12.17 Chemical Properties of Line- Line -angle formula angle formula: T : The hydrogen atoms are removed from he hydrogen atoms are removed from 12.18 12.18 Nomenclature and Properties of Halogenated Alkanes Nomenclature and Properties of Halogenated Alkanes Chemical Connections: Chlorofluorocarbons and the Chemical Connections: Chlorofluorocarbons and the carbon chains, leaving just a carbon line skeleton with carbon chains, leaving just a carbon line skeleton with functional groups attached to it. Ozone Layer Ozone Layer functional groups attached to it. Chemistry 121, Winter 2008, LA Tech Chemistry 121, Winter 2008, LA Tech 1-3 Chemistry 121, Winter 2008, LA Tech Chemistry 121, Winter 2008, LA Tech 1-4
Alicyclic Alicyclic Alkanes Alkanes Organic Nomenclature Organic Nomenclature Are saturated hydrocarbons: Organic molecules can be very complex. Organic molecules can be very complex. •Noncyclic Noncyclic alkanes alkanes: : General molecular formula, C n H 2n+2 • Naming system must be able to tell Naming system must be able to tell Structural formula: Structural formula: • • Number of carbons in the longest chain Number of carbons in the longest chain • • The location of any branches The location of any branches • • Which functional groups are present and where Which functional groups are present and where they are located. they are located. The The IUPAC IUPAC Nomenclature System provides a Nomenclature System provides a uniform set of rules that we can follow. uniform set of rules that we can follow. Chemistry 121, Winter 2008, LA Tech Chemistry 121, Winter 2008, LA Tech 1-5 Chemistry 121, Winter 2008, LA Tech Chemistry 121, Winter 2008, LA Tech 1-6 Naming Naming alkanes alkanes Alkanes Alkanes 1 1 Find the longest carbon chain. Find the longest carbon chain. Use as base name with an ane Use as base name with an ane ending. ending. First four members of the alkanes alkanes First four members of the 2 Locate any branches on chain. 2 Locate any branches on chain. Name # of C Condensed formula Use base names with a yl Use base names with a yl ending. ending. Name # of C Condensed formula 3 For multiple branch of the same type, For multiple branch of the same type, Methane Methane 1 1 CH 4 CH 3 4 modify name with di di, tri, ... , tri, ... modify name with Ethane Ethane 2 2 CH CH 3 3 CH CH 3 3 4 Show the location of each branch with Show the location of each branch with 4 Propane Propane 3 3 CH CH 3 3 CH CH 2 2 CH CH 3 numbers. numbers. 3 5 5 List multiple branches alphabetically List multiple branches alphabetically Butane Butane 4 4 CH 3 CH 3 CH CH 2 2 CH CH 2 2 CH CH 3 3 - - the di the di, tri, ... don , tri, ... don’ ’t count.. t count.. Called a Called a homologous series homologous series • “Members differ by number of CH 2 groups” Chemistry 121, Winter 2008, LA Tech Chemistry 121, Winter 2008, LA Tech 1-7 Chemistry 121, Winter 2008, LA Tech Chemistry 121, Winter 2008, LA Tech 1-8
Isomerism Isomerism Nomenclature: Nomenclature: Unbranched Unbranched or straight chain or straight chain alk alkanes anes Isomers - Isomers - different compounds having the same molecular different compounds having the same molecular General molecular formula: C n H 2n+2 formula but different structural formulas formula but different structural formulas All bond angles about tetrahedral carbon are approximately 109.5° There are two type of Isomers: There are two type of Isomers: Molecular Molecular Constitutional isomerism: : Different connections Different connections among among Constitutional isomerism Name Name Formula Formula atoms in the atoms in the methane CH 4 nonane C 9 H 2 0 • Skeleton ethane C 2 H 6 decane C 10 H 2 2 • Position propane • Functional group C 3 H 8 dodecane C 12 H 2 6 Stereoisomerism: Stereoisomerism : Same connectivity Same connectivity among atoms, but among atoms, but butane C 4 H 10 tetradecane C 14 H 3 0 these atoms differ in spatial orientation these atoms differ in spatial orientation pentane C 5 H 12 hexadecane C 16 H 3 4 • geometric hexane C 6 H 14 octadecane C 18 H 3 8 • conformational • optical heptane C 7 H 16 eicosane C 20 H 4 2 octane C 8 H 1 8 Chemistry 121, Winter 2008, LA Tech Chemistry 121, Winter 2008, LA Tech 1-9 Chemistry 121, Winter 2008, LA Tech Chemistry 121, Winter 2008, LA Tech 1-10 Constitutional Isomers Constitutional isomers in butane Constitutional isomers in butane Skeletal (Chp. 12) CH 3 Constitutional isomers: Constitutional isomers : compounds with the same compounds with the same molecular formula but a different connectivity of their molecular formula but a different connectivity of their CH 3 CH 2 CH 2 CH 3 CH 3 CHCH 3 atoms in the skeleton. Functional (Chp. 14) atoms in the skeleton. Positional (Chp. 12) There are two constitutional isomers with molecular There are two constitutional isomers with molecular CH 3 CH 2 CH 2 CH 3 CH CH 3 CH 3 CH 2 OH CH 3 O CH 3 formula C formula C 4 4 H H 10 Br Br 10 Stereoisomers Stereoisomers Geometric (Chp. 13) Conformational (Chp.12) CH 3 CH 3 CH 3 H H H Br H CH 3 C C C C H Br Br Br H H H H H H H Enantiomers (Optical) (Chp. 16) CH 3 CO 2 H CO 2 H CH 3 CH 2 CH 2 CH 3 CH 3 CHCH 3 C C Butane 2-Methylpropane H OH HO H (bp -0.5°C) (bp -11.6°C) CH 3 CH 3 Chemistry 121, Winter 2008, LA Tech Chemistry 121, Winter 2008, LA Tech 1-11 Chemistry 121, Winter 2008, LA Tech Chemistry 121, Winter 2008, LA Tech 1-12
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