Effect of the Degree of Unsaturation of Biodiesel Fuels on the Exhaust
Where necessary, the position of the unsaturation is numbered…
description
Transcript of Where necessary, the position of the unsaturation is numbered…
The diversity of organic compounds leads to ...
Organic NomenclatureTrivial (historic) names...
CH3CO2H
CH3OH
HCO2H
HO2CCH2CO2H
Compound names have four fields:
Root Unsaturations Functional GroupSubstituents
Systematic IUPAC Nomenclature:
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The compound root name is based on the number of carbon atoms in the longest continuous chain or ring.
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CnH2n+2CH4CH3CH3CH3CH2CH3CH3(CH2)2CH3CH3(CH2)3CH3CH3(CH2)4CH3CH3(CH2)5CH3CH3(CH2)6CH3CH3(CH2)7CH3CH3(CH2)8CH3CH3(CH2)9CH3CH3(CH2)10CH3CH3(CH2)11CH3CH3(CH2)12CH3CH3(CH2)13CH3CH3(CH2)14CH3CH3(CH2)15CH3CH3(CH2)16CH3CH3(CH2)17CH3CH3(CH2)18CH3
AlkaneMethaneEthanePropaneButanePentaneHexaneHeptaneOctaneNonaneDecaneUndecaneDodecaneTridecaneTetradecanePentadecaneHexadecaneHeptadecaneOctadecaneNonadecaneEicosane
Cycloalkanes...
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The presence of multiple bonds is indicated by changing the "a" of the "ane" into "ene" or "yne" in the third field of the name.
H2C CHCH3CH3CH2CH3 HC CCH3
1,3-cyclopentadiene
Where necessary, the position of the unsaturation is numbered…
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COH
O
CO2H Carboxylic acid -anoic acid
The presence of functional groups is indicated using the suffixes of Table 1.1Functional groups are given the smallest possible number of the longest chain.
H3CC
OH
O
CH3CH3
N
H
H
Amine -amineNH2
NH2
NH2
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H3CH2CC
CH2CH3
O
H3CC
CH2CH2CH3
O
H C CH2CH2CH2CH3
O
pentan-3-one
pentan-2-one
pentanal
HC
O
H
CH2CH3
H pentenal
pent-2-enal
trans-pent-2-enal
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H3C C C CH2 CH2 CH2 OH
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Hex-4-yn-1-ol
O
Cyclopent-2-enone
O
Cl5-chlorocyclopent-2-enone
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SubstituentsStructural elements (sometimes functional groups) that are not part of the longest chain, but attached to it.
• appear first in the name of a compound
• each is numbered with respect to their position.
• where there is a choice of numbering possibilities, that with the smallest first number is used.
• the substituent name is prefixed with an indication of the number of such substituents if more than one is present (di, tri, tetra, penta etc.)
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• Some common substituents include:
Name Name Name
-CH3 methyl -OCH3 methoxy -F fluoro
-CH2CH3 ethyl -OCH2CH3 ethoxy -Cl chloro
-CH2CH2CH3 propyl -OCH2CH2CH3 propoxy -Br bromo
-CH2CH2CH2CH3 butyl -OCH2CH2CH2CH3 butoxy -I iodo
etc. etc. -NO2 nitro
-CH(CH3)2 isopropyl -OCH(CH3)2 isopropoxy -C6H5 phenyl
-C(CH3)3 t-butyl -OC(CH3)3 t-butoxy -CH2C6H5 benzyl
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• In summary, to name an organic molecule, work back-to-front:– Find the principal functional group.– Find the longest chain (or ring) including the principal functional group
and all double/triple bonds.– Number the chain starting at whichever end gives the principal functional
group the lower number. (For a ring, start numbering at the principal functional group.)
– Name the principal functional group, numbering if necessary.
– Name the main chain (or ring), numbering the C=C or CC bonds if necessary. If this gives a name in which the next letter after the ‘e’ of ‘ane’, ‘ene’ or ‘yne’ is a vowel, drop the ‘e’.
– Name and number the substituents on the main chain. If a substituent appears more than once, use a prefix to indicate how many there are and include a number for each appearance. List the substituents in alphabetical order (not counting prefixes i.e. trichloro comes before dimethyl because c comes before m) followed by the main chain (or ring) name.
– Finally, add cis- or trans- to the front of the name if necessary.
OBr
Br
CH3O1
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OBr
Br
CH3O
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CH3CHCH2CHCH2CH2CH3
CH2
CH3
OH
O
OH
O
OH
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CHO
Br
F Cl
F
Ph
Ph
O
O2N CO2H CF3CH2OH
O
OCH2CH3
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C
CC
C
CC
H
H
H
H
H
H
Benzene
Molecules with this substructure are treated as a class - the arenes.
CH3 NH2 OH OCH3 CO2H
Toluene Aniline Phenol Anisole Benzoic Acid
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CH3
Cl
O2N
C(CH3)3
OH
H3CO
Cl
Cl
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• Esters can be made by reacting a carboxylic acid with an alcohol:
• Their names reflect this. The chain from the alcohol is named as a substituent followed by a space. Then the carboxylic acid is named, changing the suffix from ‘–oic acid’ to ‘–oate’.e.g. The ester above was made from ethanol and benzoic acid.
It is called ethyl benzoate.
• What is the structure of octyl ethanoate?
O
OO
OH OH
OH H+ +
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• Amides are made by reacting a carboxylic acid with an amine:
• Their names reflect this. The chain from the amine is named as a substituent followed by a space. Then the carboxylic acid is named, changing the suffix from ‘–oic acid’ to ‘–amide’.
e.g. The amide above was made from ethanamine and benzoic acid.
It is called ethyl benzamide.
• What is the structure of propyl hexanamide?
N
O
H
O
OH N
H
HO
H H+ +
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Organic chemical reactions can be classified into several basic categories:
Proton-transfer reactions (Brønsted acid/base reactions)SubstitutionAddition and EliminationOxidation and Reduction
Proton-transfer reactions...
N + HCl N H + Cl
H3CC
OH
O
+ NaOHH3C
CO
O
Na + H2O
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Substitution
OH + NaBrH2SO4
Br
Br + NaCN CN
H3CC
Cl
O
+ NH3
H3CC
NH2
O
Br2, FeBr3
Br
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Elimination Reactions ... the reverse of addition, forms a pi bond.
Br + KOH
H3CH2CC
CH3
H3CO OH
H3CH2CC
CH3
O
+ CH3OH
Addition Reactions ...to a pi bond.
H2CC
CH3
H
Br2
CH2
CCH3
H
Br
Br
H3CC
CH3
O 1) NaCN2) H2SO4
H3CC
CH3
HO CN
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Oxidation ...the addition of O or removal of H2
CH2OHPCC
C
O
H
KMnO4 C
O
OH
Reductions ...the addition of hydrogen, H2
C
O
HCH2OH C
O
OH
NaBH4, CH3OH
LiAlH4, ethyl ether
Ph
H
H
CO2H H2, Pd/C
Ph
H
H
CO2H
H
H
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CH3C
CH3
CH3
BrCH3OH C
H3C
CH3
CH3
OCH3
Practice!
O
O
H3COH2C
O
O 1) CH3Li, ethyl ether, 0°C2) H2O
O
HO
H3COH2C
O
O
H3C
H3C
H
H
CH3MCPBA
H3C
H
H
CH3O
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H3C
H
H
CH3 Br2CH3CHBrCHBrCH3
NO2HNO3, H2SO4
OHPBr3
Br
CN LiAlH4, ethyl ether
CH2NH2
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Kinetics and Reaction Mechanism
•Reactions take place as a result of collisions between molecules/ions.•These collisions are are called “elementary processes”.•In these processes, bonds are broken and/or formed if the collision is sufficiently energetic (to overcome ∆G‡) and the collision geometry is appropriate. •The overall conversion of reactants to products may involve several elementary processes.
Understanding electron movement is a critical part of understanding chemical reactions.
BrC
CH2
H3C CH3
C
CH3
CH3H3C
H Br
BrC
CH3
CH3H3C
C
CH3
CH3H3C
Br
1)
2)
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Electrophiles and Nucleophiles - the components of polar reactions.
Nucleophiles are species that seek positiveness. They can be anionic, negatively polarized or electron-rich…
Electrophiles are species that seek negativeness. They can be cations, positively polarized, or electron deficient.
Br
O
H
H
C
CH2
H3C CH3C
O
H3C CH3O
H
C
O
H3C CH3
Br BrO
H
HH C
CH3
CH3H3C
H Br
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Arrow Pushing...
Organic chemists use arrows to indicate the flow of electrons during reactions. The importance of this formalism cannot be overstated.
Arrows always start at electron pairs (either lone pairs or bonds).
ARROWS NEVER INDICATE THE MOVEMENT OF AN ATOM.
C
O
H NH2 HC
NH2
O
When pushing electrons, remember that period 2 elements (including C, N and O) can NEVER have more than 8 electrons
H2CC
CH2
H
CH2C
H2C
H
C
O
H O HC
O
O
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N C H S
H
N C H S
H
N C H O
H
HN C H
H
O
H
H O NCH NCH
OH
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B
F
F FN
CH3
H3C CH3
B N
F
F
F
CH3
CH3
CH3
C
O
HH
B
F
F F C
O
HH
B
FF
F
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CH2
CH3C CH3
H2C
CH3C CH3
H O
H
H
H
O
H
H O
H
HH O
H
H
H
CH2
CH3C CH3
H Br
CH3
CH3C CH3
Br
H
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CN
H
C Cl
HH
H
CC
H H
N Cl
H3C
C Br
HH
H
CI
H H
BrI
CN
H3C
C O
H3C
H3C
CC
H3C
ON
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CH3
CH3C CH3
+Br
H3C
CH3C
CH3
Br
C
O
HH
H
OH
H
H3C
CH3C
CH3
Br CH3
CH3C CH3
+Br
C
O
HH
H
H
OH
H
O
H
C
O
HH
H
C
O
HH
H
H
OH